[
{"topic":"Osteology - Clavicle","question":"The clavicle is classified as which type of bone?","options":["Long bone with a shaft and two ends, but no medullary cavity in the classic sense","Sesamoid bone","Flat bone","Irregular bone"],"correct_index":0,"explanation":"The clavicle is a long bone but atypical: it lacks a true medullary cavity along most of its length and ossifies partly in membrane (shaft) and partly in cartilage (ends), making it the first bone to start ossifying in the fetus."},
{"topic":"Osteology - Clavicle","question":"Which end of the clavicle is quadrangular (roughly square) in cross-section, and which is flattened?","options":["Sternal end quadrangular; acromial end flattened","Acromial end quadrangular; sternal end flattened","Both ends quadrangular","Both ends flattened"],"correct_index":0,"explanation":"The medial (sternal) end of the clavicle is quadrangular and articulates with the manubrium; the lateral (acromial) end is flattened and articulates with the acromion of the scapula."},
{"topic":"Osteology - Clavicle","question":"The conoid tubercle, which gives attachment to the conoid ligament, is located on which part of the clavicle?","options":["Medial third, superior surface","Lateral third, inferior surface, posterior border","Middle third, anterior border","Sternal end"],"correct_index":1,"explanation":"The conoid tubercle lies on the inferior surface of the lateral third of the clavicle at the posterior border, providing attachment for the conoid ligament (part of the coracoclavicular ligament)."},
{"topic":"Osteology - Clavicle","question":"The clavicle is most commonly fractured at which point?","options":["Sternal end","Junction of the middle and lateral thirds","Acromial end","Middle third only, medial to the subclavius groove"],"correct_index":1,"explanation":"The clavicle most commonly fractures at the junction of its middle and lateral thirds, which is its weakest point structurally and also where the curvatures change direction."},
{"topic":"Osteology - Clavicle","question":"The subclavian groove on the inferior surface of the clavicle gives attachment to:","options":["Subclavius muscle","Deltoid muscle","Trapezius muscle","Pectoralis major muscle"],"correct_index":0,"explanation":"The subclavian groove on the inferior surface of the middle third of the clavicle gives attachment to the subclavius muscle, which protects the underlying subclavian vessels and brachial plexus."},
{"topic":"Osteology - Scapula","question":"The scapula is a __ bone lying in which region?","options":["Long bone; anterior chest wall","Flat bone; posterolateral chest wall (between T2-T7 ribs)","Irregular bone; upper limb girdle only","Sesamoid bone; shoulder joint"],"correct_index":1,"explanation":"The scapula is a flat, triangular bone lying on the posterolateral aspect of the thoracic wall, typically extending from the level of the 2nd to the 7th rib."},
{"topic":"Osteology - Scapula","question":"The glenoid cavity of the scapula faces which direction and articulates with which bone?","options":["Faces medially; articulates with the clavicle","Faces laterally; articulates with the head of the humerus","Faces posteriorly; articulates with the acromion","Faces inferiorly; articulates with the coracoid process"],"correct_index":1,"explanation":"The glenoid cavity, a shallow pear-shaped depression at the lateral angle of the scapula, faces laterally (and slightly anteriorly/superiorly) and articulates with the head of the humerus to form the shoulder joint."},
{"topic":"Osteology - Scapula","question":"The coracoid process of the scapula projects from which part of the bone?","options":["Inferior angle","Superior border, near the scapular notch","Lateral border","Medial (vertebral) border"],"correct_index":1,"explanation":"The coracoid process arises from the superior border of the scapula, just lateral to the suprascapular notch, and projects anterolaterally, serving as an attachment site for several muscles and ligaments."},
{"topic":"Osteology - Scapula","question":"Which structure passes through the suprascapular notch (deep to the superior transverse scapular ligament)?","options":["Suprascapular artery","Suprascapular nerve","Axillary nerve","Both suprascapular artery and nerve"],"correct_index":1,"explanation":"The suprascapular nerve passes through (below) the suprascapular notch under the superior transverse scapular ligament, while the suprascapular artery usually passes above the ligament - a useful anatomical distinction ('army over, navy under' style mnemonics vary, but the nerve is below)."},
{"topic":"Osteology - Scapula","question":"The infraspinatus fossa on the posterior surface of the scapula lodges which muscle?","options":["Supraspinatus","Infraspinatus","Teres minor","Subscapularis"],"correct_index":1,"explanation":"The infraspinatus fossa, below the spine of the scapula on its posterior surface, is occupied by the infraspinatus muscle."},
{"topic":"Osteology - Scapula","question":"The subscapular fossa, which lodges subscapularis muscle, is located on which surface of the scapula?","options":["Posterior (dorsal) surface","Anterior (costal) surface","Superior border","Lateral border"],"correct_index":1,"explanation":"The subscapular fossa is the slightly concave anterior (costal) surface of the scapula, occupied by the subscapularis muscle."},
{"topic":"Osteology - Scapula","question":"The acromion process of the scapula articulates with the clavicle at which joint?","options":["Sternoclavicular joint","Acromioclavicular joint","Glenohumeral joint","Scapulothoracic 'joint'"],"correct_index":1,"explanation":"The acromion, the lateral extension of the scapular spine, articulates with the lateral (acromial) end of the clavicle to form the acromioclavicular joint."},
{"topic":"Osteology - Scapula","question":"Which angle of the scapula gives attachment to the inferior fibers of serratus anterior and is used clinically to assess scapular winging?","options":["Superior angle","Lateral angle","Inferior angle","Acromial angle"],"correct_index":2,"explanation":"The inferior angle of the scapula receives attachment from the lower fibers of serratus anterior and slides laterally when serratus anterior is weak, producing winging that is most obvious at this angle."},
{"topic":"Osteology - Scapula","question":"The spine of the scapula divides the posterior (dorsal) surface into which two fossae?","options":["Subscapular and infraspinatus fossae","Supraspinatus and infraspinatus fossae","Glenoid and coracoid fossae","Costal and dorsal fossae"],"correct_index":1,"explanation":"The spine of the scapula runs obliquely across the posterior surface, separating the supraspinatus fossa above from the infraspinatus fossa below."},
{"topic":"Osteology - Humerus","question":"The anatomical neck of the humerus separates the head from the:","options":["Shaft directly","Greater and lesser tubercles","Surgical neck","Deltoid tuberosity"],"correct_index":1,"explanation":"The anatomical neck is the slightly constricted region separating the rounded head of the humerus from the greater and lesser tubercles; it corresponds to the old epiphyseal line."},
{"topic":"Osteology - Humerus","question":"The surgical neck of the humerus lies at the junction of the shaft with which structures, and is clinically important because it lies close to which nerve?","options":["Tubercles; close to axillary nerve","Deltoid tuberosity; close to median nerve","Epicondyles; close to ulnar nerve","Capitulum; close to radial nerve"],"correct_index":0,"explanation":"The surgical neck lies just below the tubercles at the junction with the shaft, and the axillary nerve together with the posterior circumflex humeral vessels lies in close relation, making it vulnerable in surgical neck fractures."},
{"topic":"Osteology - Humerus","question":"The bicipital (intertubercular) groove of the humerus lodges which structure?","options":["Tendon of long head of biceps brachii","Tendon of triceps brachii","Radial nerve","Axillary artery"],"correct_index":0,"explanation":"The intertubercular (bicipital) groove, between the greater and lesser tubercles, transmits the tendon of the long head of biceps brachii along with an ascending branch of the anterior circumflex humeral artery."},
{"topic":"Osteology - Humerus","question":"The deltoid tuberosity is located on which surface of the humeral shaft and gives insertion to which muscle?","options":["Anterolateral surface; deltoid","Posteromedial surface; triceps","Anteromedial surface; coracobrachialis","Posterior surface; latissimus dorsi"],"correct_index":0,"explanation":"The deltoid tuberosity is a roughened area on the anterolateral surface of the middle of the humeral shaft, providing insertion for the deltoid muscle."},
{"topic":"Osteology - Humerus","question":"The radial (spiral) groove on the posterior surface of the humerus transmits which nerve and artery?","options":["Ulnar nerve and superior ulnar collateral artery","Radial nerve and profunda brachii artery","Median nerve and brachial artery","Axillary nerve and posterior circumflex humeral artery"],"correct_index":1,"explanation":"The radial (spiral) groove runs obliquely across the posterior surface of the humeral shaft and transmits the radial nerve together with the profunda brachii (deep brachial) artery, making midshaft fractures a risk for radial nerve injury."},
{"topic":"Osteology - Humerus","question":"Which epicondyle of the humerus is related to the ulnar nerve, which passes directly behind it?","options":["Lateral epicondyle","Medial epicondyle","Both equally","Neither, it is related to the olecranon only"],"correct_index":1,"explanation":"The ulnar nerve passes posterior to the medial epicondyle of the humerus in a groove, making this a common site of injury ('funny bone')."},
{"topic":"Osteology - Humerus","question":"The capitulum of the distal humerus articulates with which forearm bone?","options":["Ulna","Radius","Both radius and ulna equally","Neither - it articulates with carpal bones"],"correct_index":1,"explanation":"The capitulum, the rounded lateral part of the distal humerus, articulates with the head of the radius. The trochlea (medial part) articulates with the ulna."},
{"topic":"Osteology - Humerus","question":"The trochlea of the humerus articulates with which part of the ulna?","options":["Olecranon process only","Trochlear notch","Coronoid process only","Radial notch"],"correct_index":1,"explanation":"The trochlea, a pulley-shaped surface on the medial side of the distal humerus, articulates with the trochlear notch of the ulna at the elbow joint."},
{"topic":"Osteology - Humerus","question":"The coronoid fossa on the anterior aspect of the distal humerus accommodates which structure during elbow flexion?","options":["Olecranon process of ulna","Coronoid process of ulna","Head of radius","Styloid process of ulna"],"correct_index":1,"explanation":"The coronoid fossa, above the trochlea anteriorly, receives the coronoid process of the ulna during full flexion of the elbow. The olecranon fossa posteriorly receives the olecranon during extension."},
{"topic":"Osteology - Humerus","question":"Which of the following is a common site for a supracondylar fracture of the humerus, with risk of injury to the brachial artery and median nerve?","options":["Just above the epicondyles, in the thin distal shaft","At the surgical neck","In the mid-shaft radial groove","At the greater tubercle"],"correct_index":0,"explanation":"Supracondylar fractures occur just above the humeral condyles where the bone is thin, and are notorious in children for injuring the brachial artery and median nerve lying anterior to it."},
{"topic":"Osteology - Radius","question":"The head of the radius articulates proximally with the capitulum of the humerus and also with which structure to permit pronation-supination?","options":["Trochlear notch of the ulna","Radial notch of the ulna","Coronoid process of ulna","Olecranon of ulna"],"correct_index":1,"explanation":"The head of the radius articulates with the radial notch of the ulna (proximal radioulnar joint) in addition to the capitulum of the humerus, allowing rotation of the radius during pronation and supination."},
{"topic":"Osteology - Radius","question":"The radial tuberosity, located just distal to the neck of the radius, gives insertion to which muscle?","options":["Brachialis","Biceps brachii","Supinator","Pronator teres"],"correct_index":1,"explanation":"The radial (bicipital) tuberosity on the anteromedial aspect of the proximal radius receives the insertion of the biceps brachii tendon."},
{"topic":"Osteology - Radius","question":"The styloid process of the radius is located at its distal end on which side?","options":["Medial side","Lateral side","Posterior side only","Anterior side only"],"correct_index":1,"explanation":"The styloid process of the radius projects from the lateral side of its distal end and is palpable in the anatomical snuffbox region; it normally lies slightly more distal than the ulnar styloid process."},
{"topic":"Osteology - Radius","question":"The distal end of the radius articulates with which carpal bones to form the wrist joint?","options":["Scaphoid and lunate","Lunate and triquetrum","Scaphoid and triquetrum","Trapezium and trapezoid"],"correct_index":0,"explanation":"The distal radius has a concave articular surface divided by a low ridge into two facets for the scaphoid (laterally) and lunate (medially) bones, forming the radiocarpal (wrist) joint."},
{"topic":"Osteology - Radius","question":"A Colles' fracture typically involves a fracture of the radius at which location?","options":["Head of radius","Neck of radius","Distal end of radius, about 2-3 cm proximal to the wrist","Radial tuberosity"],"correct_index":2,"explanation":"A Colles' fracture is a fracture of the distal radius (within about 2-3 cm of the articular surface) with characteristic dorsal displacement of the distal fragment, producing a 'dinner fork' deformity."},
{"topic":"Osteology - Ulna","question":"The trochlear (semilunar) notch of the ulna is bounded by which two processes?","options":["Coronoid process and olecranon process","Styloid process and head","Radial notch and coronoid process","Olecranon and styloid process"],"correct_index":0,"explanation":"The trochlear notch, which articulates with the trochlea of the humerus, is formed by the olecranon process posteriorly/superiorly and the coronoid process anteriorly/inferiorly."},
{"topic":"Osteology - Ulna","question":"The olecranon process of the ulna forms the point of the elbow and receives insertion of which muscle?","options":["Biceps brachii","Brachialis","Triceps brachii","Anconeus"],"correct_index":2,"explanation":"The olecranon process, the proximal posterior projection of the ulna forming the bony point of the elbow, receives the insertion of the triceps brachii tendon."},
{"topic":"Osteology - Ulna","question":"The radial notch of the ulna, on its lateral side, articulates with which structure?","options":["Head of radius","Styloid process of radius","Capitulum of humerus","Trochlea of humerus"],"correct_index":0,"explanation":"The radial notch, on the lateral aspect of the coronoid process, articulates with the circumference of the head of the radius, forming the proximal radioulnar joint."},
{"topic":"Osteology - Ulna","question":"The styloid process of the ulna is located at its distal end on which side, and does NOT directly articulate with the carpal bones due to the presence of which structure?","options":["Lateral side; interosseous membrane","Posteromedial side; articular disc (triangular fibrocartilage complex)","Anterior side; pronator quadratus","Medial side; extensor retinaculum"],"correct_index":1,"explanation":"The ulnar styloid process projects from the posteromedial aspect of the distal ulna; the ulna itself is excluded from the wrist joint proper by the triangular fibrocartilage (articular disc), which separates it from the carpal bones."},
{"topic":"Osteology - Ulna","question":"The supinator crest on the proximal ulna gives attachment to part of which muscle?","options":["Pronator teres","Supinator","Anconeus","Flexor digitorum profundus"],"correct_index":1,"explanation":"The supinator crest, a ridge on the posterolateral surface of the proximal ulna below the radial notch, gives origin to part of the supinator muscle."},
{"topic":"Osteology - Hand bones","question":"How many carpal bones are present in each wrist, arranged in how many rows?","options":["7 bones in 2 rows","8 bones in 2 rows","8 bones in 3 rows","6 bones in 2 rows"],"correct_index":1,"explanation":"There are 8 carpal bones arranged in two rows of four: a proximal row (scaphoid, lunate, triquetrum, pisiform) and a distal row (trapezium, trapezoid, capitate, hamate)."},
{"topic":"Osteology - Hand bones","question":"Which carpal bone is most commonly fractured, often after a fall on an outstretched hand, and is at risk of avascular necrosis?","options":["Lunate","Scaphoid","Pisiform","Hamate"],"correct_index":1,"explanation":"The scaphoid is the most frequently fractured carpal bone, classically from a fall on an outstretched hand; because much of its blood supply enters distally, fractures risk avascular necrosis of the proximal fragment."},
{"topic":"Osteology - Hand bones","question":"The pisiform bone is unique among carpal bones because it:","options":["Is the largest carpal bone","Is a sesamoid bone within the tendon of flexor carpi ulnaris","Articulates with the radius","Forms part of the anatomical snuffbox floor"],"correct_index":1,"explanation":"The pisiform is a sesamoid bone developing within the tendon of flexor carpi ulnaris, sitting anterior to the triquetrum rather than in the same articular plane as the other proximal row carpals."},
{"topic":"Osteology - Hand bones","question":"The hook of the hamate, along with the pisiform, forms which border of the carpal tunnel?","options":["Radial (lateral) border","Ulnar (medial) border","Roof (anterior)","Floor (posterior)"],"correct_index":1,"explanation":"The pisiform and the hook of the hamate form the ulnar (medial) boundary of the carpal tunnel, while the scaphoid tubercle and trapezium form the radial boundary."},
{"topic":"Osteology - Hand bones","question":"How many metacarpal bones and phalanges are present in each hand?","options":["5 metacarpals, 14 phalanges","4 metacarpals, 14 phalanges","5 metacarpals, 15 phalanges","5 metacarpals, 10 phalanges"],"correct_index":0,"explanation":"Each hand has 5 metacarpal bones (one per digit) and 14 phalanges: the thumb has 2 phalanges (proximal, distal) and each of the other four fingers has 3 (proximal, middle, distal)."},
{"topic":"Osteology - Hand bones","question":"The 'anatomical snuffbox' is bounded medially by the tendon of which muscle?","options":["Abductor pollicis longus","Extensor pollicis longus","Extensor pollicis brevis","Flexor pollicis longus"],"correct_index":1,"explanation":"The anatomical snuffbox is bounded medially by the tendon of extensor pollicis longus and laterally by the tendons of abductor pollicis longus and extensor pollicis brevis; the scaphoid and part of the radial styloid form its floor."},
{"topic":"Osteology - Hand bones","question":"Which carpal bone lies in the floor of the anatomical snuffbox and is palpable there, useful for detecting tenderness after a fall?","options":["Lunate","Scaphoid","Trapezium","Capitate"],"correct_index":1,"explanation":"The scaphoid bone forms most of the floor of the anatomical snuffbox and can be palpated there; tenderness in this region after trauma raises suspicion for scaphoid fracture."},
{"topic":"Joints - Sternoclavicular","question":"The sternoclavicular joint is classified as which type of joint?","options":["Hinge synovial joint","Saddle-type synovial joint with an articular disc","Pivot synovial joint","Ball and socket synovial joint"],"correct_index":1,"explanation":"The sternoclavicular joint is a saddle-shaped synovial joint containing an articular disc that improves congruity and shock absorption; it is the only true articulation of the upper limb with the axial skeleton."},
{"topic":"Joints - Sternoclavicular","question":"Which ligament of the sternoclavicular joint prevents the medial end of the clavicle from being displaced upward?","options":["Anterior sternoclavicular ligament","Costoclavicular ligament","Interclavicular ligament","Conoid ligament"],"correct_index":1,"explanation":"The costoclavicular ligament, running from the first rib to the inferior surface of the clavicle, is a strong ligament that especially resists upward displacement of the clavicle's medial end."},
{"topic":"Joints - Sternoclavicular","question":"The articular disc of the sternoclavicular joint divides the joint cavity into how many compartments?","options":["One single cavity","Two separate synovial compartments","Three compartments","No true cavity is present"],"correct_index":1,"explanation":"The intra-articular disc of the sternoclavicular joint divides the joint into two separate synovial compartments, similar in principle to the temporomandibular joint disc."},
{"topic":"Joints - Acromioclavicular","question":"The acromioclavicular joint is which type of synovial joint?","options":["Plane (gliding) synovial joint","Hinge joint","Ball and socket joint","Pivot joint"],"correct_index":0,"explanation":"The acromioclavicular joint is a plane synovial joint between the acromial end of the clavicle and the acromion of the scapula, allowing gliding movements important for full range of shoulder motion."},
{"topic":"Joints - Acromioclavicular","question":"The coracoclavicular ligament, which strongly stabilizes the acromioclavicular joint, is composed of which two parts?","options":["Conoid and trapezoid ligaments","Coracoacromial and coracohumeral ligaments","Superior and inferior AC ligaments","Costoclavicular and interclavicular ligaments"],"correct_index":0,"explanation":"The coracoclavicular ligament consists of the conoid ligament (medial, cone-shaped) and trapezoid ligament (lateral, quadrilateral), connecting the coracoid process to the clavicle and providing the major support to the acromioclavicular joint."},
{"topic":"Joints - Acromioclavicular","question":"A 'shoulder separation' in clinical practice usually refers to injury of which joint?","options":["Glenohumeral joint","Sternoclavicular joint","Acromioclavicular joint","Scapulothoracic articulation"],"correct_index":2,"explanation":"A 'shoulder separation' refers to disruption of the acromioclavicular joint (and often the coracoclavicular ligament), commonly from a fall onto the shoulder, distinct from a 'dislocated shoulder' which involves the glenohumeral joint."},
{"topic":"Joints - Shoulder","question":"The shoulder (glenohumeral) joint is classified as which type of synovial joint?","options":["Hinge joint","Ball and socket joint","Saddle joint","Plane joint"],"correct_index":1,"explanation":"The glenohumeral joint is a ball and socket synovial joint between the head of the humerus and the glenoid cavity of the scapula, allowing the greatest range of movement of any joint in the body."},
{"topic":"Joints - Shoulder","question":"Which structure deepens the glenoid cavity and increases the stability of the shoulder joint?","options":["Coracoacromial ligament","Glenoid labrum","Subacromial bursa","Rotator interval"],"correct_index":1,"explanation":"The glenoid labrum, a fibrocartilaginous rim attached to the margin of the glenoid cavity, deepens the socket and increases the contact area with the humeral head, enhancing stability."},
{"topic":"Joints - Shoulder","question":"The shoulder joint is most commonly dislocated in which direction, and the humeral head displaces into which region?","options":["Posterior dislocation into the infraspinous fossa","Anterior (subcoracoid) dislocation","Superior dislocation, impinging the acromion","Inferior dislocation only, called luxatio erecta, is by far the most common"],"correct_index":1,"explanation":"The shoulder is most commonly dislocated anteriorly (subcoracoid dislocation), because the joint capsule and supporting structures are relatively weak anteroinferiorly, and this is the direction of least resistance."},
{"topic":"Joints - Shoulder","question":"The rotator cuff muscles contribute significantly to the stability of the shoulder joint by:","options":["Forming bony buttresses","Blending with and reinforcing the joint capsule","Limiting blood supply to the joint","Producing the coracoacromial arch"],"correct_index":1,"explanation":"The tendons of supraspinatus, infraspinatus, teres minor, and subscapularis blend with and reinforce the fibrous capsule of the shoulder joint, forming the 'rotator cuff' that is the major dynamic stabilizer of this inherently unstable ball-and-socket joint."},
{"topic":"Joints - Shoulder","question":"Which rotator cuff tendon is most commonly torn, often related to impingement beneath the coracoacromial arch?","options":["Subscapularis","Supraspinatus","Infraspinatus","Teres minor"],"correct_index":1,"explanation":"The supraspinatus tendon is the most commonly torn rotator cuff tendon, related to its course beneath the coracoacromial arch and a relatively poor blood supply ('critical zone') near its insertion."},
{"topic":"Joints - Shoulder","question":"Which ligament forms a protective arch over the shoulder joint, contributing to the coracoacromial arch along with the acromion and coracoid process?","options":["Coracohumeral ligament","Coracoacromial ligament","Transverse humeral ligament","Glenohumeral ligament"],"correct_index":1,"explanation":"The coracoacromial ligament spans between the coracoid process and the acromion, completing the coracoacromial arch that protects the shoulder joint superiorly and can compress the supraspinatus tendon in impingement syndrome."},
{"topic":"Joints - Shoulder","question":"The long head of biceps tendon is held in the intertubercular groove by which structure?","options":["Transverse humeral ligament","Coracoacromial ligament","Coracohumeral ligament only","Glenoid labrum"],"correct_index":0,"explanation":"The transverse humeral ligament bridges the intertubercular (bicipital) groove between the two tubercles of the humerus, holding the long head of biceps tendon in place."},
{"topic":"Joints - Elbow","question":"The elbow joint is a compound synovial joint that includes which articulations?","options":["Humeroulnar and humeroradial articulations only","Humeroulnar, humeroradial, and proximal radioulnar articulations sharing one synovial cavity","Only the proximal radioulnar joint","Humeroulnar and distal radioulnar joints"],"correct_index":1,"explanation":"The elbow joint is a compound hinge synovial joint comprising the humeroulnar, humeroradial, and proximal radioulnar articulations, all enclosed within a single joint capsule and synovial cavity."},
{"topic":"Joints - Elbow","question":"The elbow joint functions mainly as which type of joint, permitting flexion and extension?","options":["Ball and socket joint","Hinge (ginglymus) joint","Pivot joint","Saddle joint"],"correct_index":1,"explanation":"Functionally, the elbow joint (humeroulnar component) acts as a hinge joint, permitting flexion and extension in essentially one plane."},
{"topic":"Joints - Elbow","question":"Which ligament of the elbow provides the main resistance against valgus (abduction) stress and is a common site of injury in throwing athletes?","options":["Radial collateral ligament","Ulnar (medial) collateral ligament","Annular ligament","Oblique cord"],"correct_index":1,"explanation":"The ulnar (medial) collateral ligament, particularly its anterior band, resists valgus stress at the elbow and is frequently injured in overhead throwing athletes (leading to procedures like 'Tommy John surgery')."},
{"topic":"Joints - Elbow","question":"The carrying angle of the elbow, formed when the forearm is extended and supinated, is normally greater in which sex and is due to what?","options":["Greater in males; due to a larger trochlea","Greater in females; due to the obliquity of the trochlear notch/asymmetric trochlea","Equal in both sexes; due to the olecranon shape","Greater in females; due to a shorter ulna"],"correct_index":1,"explanation":"The carrying angle (normally about 5 degrees in men and up to 10-15 degrees in women) results mainly from the asymmetric shape of the trochlea and obliquity of the trochlear notch, and tends to be slightly greater in females."},
{"topic":"Joints - Elbow","question":"'Pulled elbow' (nursemaid's elbow) in young children results from:","options":["Subluxation of the head of radius through the annular ligament","Dislocation of the ulna at the trochlear notch","Fracture of the olecranon","Rupture of the ulnar collateral ligament"],"correct_index":0,"explanation":"Nursemaid's elbow occurs when a sudden pull on the extended, pronated arm of a young child causes partial subluxation of the radial head from beneath the annular (anular) ligament, which is looser in children."},
{"topic":"Joints - Radioulnar","question":"The proximal radioulnar joint is which type of synovial joint?","options":["Pivot joint","Hinge joint","Saddle joint","Ball and socket joint"],"correct_index":0,"explanation":"The proximal radioulnar joint is a pivot (trochoid) joint, where the head of the radius rotates within the annular ligament and radial notch of the ulna, enabling pronation and supination."},
{"topic":"Joints - Radioulnar","question":"The interosseous membrane connecting the radius and ulna primarily functions to:","options":["Allow independent flexion of each bone","Transmit forces from the hand to the humerus and stabilize the forearm bones during movement","Form the floor of the cubital fossa","Provide the main attachment for biceps brachii"],"correct_index":1,"explanation":"The interosseous membrane binds the radius and ulna together, transmits forces (e.g., from a fall on the hand) proximally to the humerus, and provides attachment for several deep forearm muscles, while permitting pronation-supination."},
{"topic":"Joints - Radioulnar","question":"The distal radioulnar joint is stabilized primarily by which structure?","options":["Annular ligament","Articular disc (triangular fibrocartilage complex)","Coronoid process","Radial collateral ligament"],"correct_index":1,"explanation":"The distal radioulnar joint, a pivot joint, is stabilized largely by the articular disc (triangular fibrocartilage complex) which also separates the joint from the wrist joint proper."},
{"topic":"Joints - Wrist","question":"The wrist (radiocarpal) joint is formed between the distal radius/articular disc and which carpal bones?","options":["Scaphoid, lunate, and triquetrum","Trapezium, trapezoid, and capitate","Only the lunate","Hamate and capitate"],"correct_index":0,"explanation":"The radiocarpal (wrist) joint is formed proximally by the distal radius and the articular disc, and distally by the proximal row of carpal bones: scaphoid, lunate, and triquetrum."},
{"topic":"Joints - Wrist","question":"The wrist joint is classified functionally as which type of synovial joint?","options":["Hinge joint","Ellipsoid (condyloid) joint","Pivot joint","Plane joint"],"correct_index":1,"explanation":"The radiocarpal joint is an ellipsoid (condyloid) synovial joint, permitting flexion, extension, abduction, adduction, and combinations (circumduction), but not rotation."},
{"topic":"Joints - Hand","question":"The metacarpophalangeal joints (except the thumb) are classified as which type of synovial joint?","options":["Hinge joints","Ellipsoid (condyloid) joints","Saddle joints","Pivot joints"],"correct_index":1,"explanation":"The metacarpophalangeal joints of the fingers are ellipsoid (condyloid) synovial joints permitting flexion, extension, abduction, and adduction, unlike the interphalangeal joints, which are simple hinge joints."},
{"topic":"Joints - Hand","question":"The carpometacarpal joint of the thumb is which type of synovial joint, allowing opposition?","options":["Hinge joint","Saddle joint","Ball and socket joint","Plane joint"],"correct_index":1,"explanation":"The first carpometacarpal joint (trapezium with first metacarpal) is a saddle-shaped synovial joint, which uniquely allows the wide range of movement including opposition that is characteristic of the human thumb."},
{"topic":"Surface Anatomy - Pectoral Region","question":"The clavipectoral triangle (deltopectoral triangle) is bounded by deltoid, pectoralis major, and which structure, and contains which vein?","options":["Clavicle superiorly; cephalic vein","Sternum medially; basilic vein","Coracoid process; axillary vein","First rib; subclavian vein"],"correct_index":0,"explanation":"The deltopectoral (clavipectoral) triangle is bounded by the clavicle superiorly and the medial borders of deltoid and pectoralis major, and it transmits the cephalic vein as it drains into the axillary vein."},
{"topic":"Surface Anatomy - Pectoral Region","question":"Pectoralis major is supplied mainly by which nerves?","options":["Long thoracic nerve only","Medial and lateral pectoral nerves","Thoracodorsal nerve","Intercostobrachial nerve"],"correct_index":1,"explanation":"Pectoralis major receives its nerve supply from both the medial and lateral pectoral nerves, branches of the medial and lateral cords of the brachial plexus respectively."},
{"topic":"Surface Anatomy - Pectoral Region","question":"Which muscle lies deep to pectoralis major and is supplied by the medial pectoral nerve alone?","options":["Serratus anterior","Pectoralis minor","Subclavius","Subscapularis"],"correct_index":1,"explanation":"Pectoralis minor, lying deep to pectoralis major, is supplied solely by the medial pectoral nerve, which pierces through it to also reach pectoralis major."},
{"topic":"Surface Anatomy - Pectoral Region","question":"The nipple in a normal adult male typically lies at the level of which intercostal space/rib?","options":["Second intercostal space","Fourth intercostal space","Sixth rib","Eighth intercostal space"],"correct_index":1,"explanation":"In an adult male, the nipple usually lies over the fourth intercostal space, approximately in the midclavicular line, though this is variable and less reliable in females."},
{"topic":"Surface Anatomy - Pectoral Region","question":"Pectoralis major has how many heads/parts of origin, and what are they?","options":["Two parts: clavicular and sternocostal","Three parts: clavicular, sternal, and abdominal only","One continuous origin from the sternum only","Four parts including a scapular head"],"correct_index":0,"explanation":"Pectoralis major classically has a clavicular head (from the medial half of the clavicle) and a larger sternocostal head (from the sternum, upper costal cartilages, and aponeurosis of external oblique)."},
{"topic":"Surface Anatomy - Axilla","question":"The axilla is described as a pyramidal space with how many walls, an apex, and a base?","options":["Three walls","Four walls","Five walls","Six walls"],"correct_index":1,"explanation":"The axilla is a pyramidal fat-filled space with four walls (anterior, posterior, medial, lateral), a narrow apex (cervicoaxillary canal), and a base formed by skin and fascia in the armpit."},
{"topic":"Surface Anatomy - Axilla","question":"The apex of the axilla, also called the cervicoaxillary canal, is bounded by the clavicle, the first rib, and which structure?","options":["Coracoid process of the scapula","Upper border of the scapula","Manubrium sterni","Acromion process"],"correct_index":1,"explanation":"The apex of the axilla (cervicoaxillary canal), through which the axillary vessels and brachial plexus pass into the arm, is bounded by the clavicle anteriorly, the upper border of the scapula posteriorly, and outer border of the first rib medially."},
{"topic":"Surface Anatomy - Axilla","question":"The posterior wall of the axilla is formed by which muscles?","options":["Pectoralis major and minor","Subscapularis, teres major, and latissimus dorsi","Serratus anterior","Biceps brachii and coracobrachialis"],"correct_index":1,"explanation":"The posterior wall of the axilla is formed by subscapularis (above) along with teres major and latissimus dorsi (below), all attached to the scapula and running toward the humerus."},
{"topic":"Surface Anatomy - Axilla","question":"The medial wall of the axilla is formed by which structures?","options":["Serratus anterior overlying the upper ribs and intercostal spaces","Pectoralis major and minor","Humerus, coracobrachialis, and short head of biceps","Subscapularis and teres major"],"correct_index":0,"explanation":"The medial wall of the axilla is formed by the upper four or five ribs with their intercostal muscles, covered by serratus anterior."},
{"topic":"Surface Anatomy - Axilla","question":"The lateral wall of the axilla, the narrowest wall, is formed by:","options":["Serratus anterior","The intertubercular groove of the humerus (with coracobrachialis and biceps)","Latissimus dorsi","Pectoralis minor"],"correct_index":1,"explanation":"The lateral wall of the axilla is the narrowest wall, formed by the intertubercular (bicipital) groove of the humerus, together with coracobrachialis and the short head of biceps brachii."},
{"topic":"Surface Anatomy - Axilla","question":"Which major neurovascular bundle is contained within the axilla?","options":["Femoral vessels and nerve","Axillary artery, axillary vein, and brachial plexus (cords/branches)","Subclavian artery and vein only","Radial and ulnar arteries"],"correct_index":1,"explanation":"The axilla transmits the axillary artery, axillary vein, and the cords and branches of the brachial plexus, along with lymph nodes and fat."},
{"topic":"Surface Anatomy - Axilla","question":"The axillary lymph nodes are typically grouped into how many main groups?","options":["Three groups","Four groups","Five groups","Six groups"],"correct_index":2,"explanation":"The axillary lymph nodes are classically described in five groups: anterior (pectoral), posterior (subscapular), lateral (humeral), central, and apical groups."},
{"topic":"Surface Anatomy - Axilla","question":"Which group of axillary lymph nodes receives lymph mainly from the lateral quadrants of the breast and is often the first site of breast cancer metastasis?","options":["Apical group","Anterior (pectoral) group","Posterior (subscapular) group","Lateral (humeral) group"],"correct_index":1,"explanation":"The anterior (pectoral) group of axillary lymph nodes, lying along the lower border of pectoralis minor, drains the lateral quadrants of the breast and is a common early site of metastatic spread in breast carcinoma."},
{"topic":"Surface Anatomy - Axilla","question":"All efferents from the axillary lymph node groups eventually drain into which final group before leaving the axilla?","options":["Central group","Apical group","Anterior group","Lateral group"],"correct_index":1,"explanation":"Lymph from all other axillary node groups ultimately drains into the apical group of axillary nodes, which in turn drains into the subclavian lymph trunk."},
{"topic":"Surface Anatomy - Spaces","question":"The quadrangular space is bounded by teres minor, teres major, the long head of triceps, and which bone, and transmits which nerve?","options":["Humerus; axillary nerve and posterior circumflex humeral vessels","Scapula; suprascapular nerve","Radius; radial nerve","Clavicle; musculocutaneous nerve"],"correct_index":0,"explanation":"The quadrangular space is bounded by teres minor above, teres major below, the long head of triceps medially, and the surgical neck of the humerus laterally; it transmits the axillary nerve and posterior circumflex humeral vessels."},
{"topic":"Surface Anatomy - Spaces","question":"The triangular space (bounded by teres minor, long head of triceps, and teres major... actually by teres minor, teres major, and the long head of triceps only, without the humerus) transmits which artery?","options":["Posterior circumflex humeral artery","Circumflex scapular artery","Profunda brachii artery","Suprascapular artery"],"correct_index":1,"explanation":"The triangular space is bounded by teres minor above, teres major below, and the long head of triceps laterally; it transmits the circumflex scapular artery, a branch of the subscapular artery."},
{"topic":"Surface Anatomy - Spaces","question":"The triangular interval is bounded by teres major, the long head of triceps, and the shaft of the humerus (lateral head of triceps), and transmits which nerve?","options":["Axillary nerve","Radial nerve and profunda brachii artery","Ulnar nerve","Musculocutaneous nerve"],"correct_index":1,"explanation":"The triangular interval is bounded by teres major above, the long head of triceps medially, and the humeral shaft (lateral head of triceps) laterally; it transmits the radial nerve and profunda brachii vessels from the posterior to the anterior/lateral compartment."},
{"topic":"Surface Anatomy - Spaces","question":"Which of these three spaces around the scapular/axillary region transmits the axillary nerve?","options":["Triangular space","Triangular interval","Quadrangular space","None of these"],"correct_index":2,"explanation":"Of the three spaces (quadrangular space, triangular space, triangular interval), only the quadrangular space transmits the axillary nerve, along with the posterior circumflex humeral vessels."},
{"topic":"Surface Anatomy - Fascia/Lymph","question":"The clavipectoral fascia extends between the clavicle and which muscle, enclosing subclavius above and pectoralis minor below?","options":["Pectoralis minor","Pectoralis major","Deltoid","Serratus anterior"],"correct_index":0,"explanation":"The clavipectoral fascia splits to enclose subclavius superiorly and pectoralis minor inferiorly, extending from the clavicle down to blend with the axillary fascia; its lower thickened part is the suspensory ligament of the axilla."},
{"topic":"Surface Anatomy - Fascia/Lymph","question":"The part of the clavipectoral fascia that pierces to transmit the cephalic vein, thoracoacromial vessels, and lateral pectoral nerve is called the:","options":["Suspensory ligament of axilla","Costocoracoid membrane","Axillary sheath","Pectoral fascia"],"correct_index":1,"explanation":"The costocoracoid membrane, the part of the clavipectoral fascia between the clavicle and pectoralis minor/coracoid process, is pierced by the cephalic vein, thoracoacromial vessels, and the lateral pectoral nerve."},
{"topic":"Surface Anatomy - Fascia/Lymph","question":"The axillary sheath, a fascial extension enclosing the axillary vessels and brachial plexus cords, is derived from which cervical fascia?","options":["Superficial cervical fascia","Prevertebral layer of deep cervical fascia","Pretracheal fascia","Investing layer of deep cervical fascia"],"correct_index":1,"explanation":"The axillary sheath is a downward prolongation of the prevertebral layer of the deep cervical fascia, enclosing the axillary artery, vein, and brachial plexus cords as they pass into the axilla."},
{"topic":"Veins - Cephalic Vein","question":"The cephalic vein begins from the dorsal venous network of the hand on which side and ascends along which border of the forearm and arm?","options":["Ulnar side of dorsal venous network; medial border","Radial side of dorsal venous network; lateral border","Midline of dorsal venous network; posterior border","Radial side; drains directly into basilic vein at the wrist"],"correct_index":1,"explanation":"The cephalic vein arises from the radial side of the dorsal venous network of the hand and ascends along the lateral (radial) borders of the forearm and arm before draining into the axillary vein."},
{"topic":"Veins - Cephalic Vein","question":"The cephalic vein ultimately drains into which vein, after passing through the deltopectoral triangle and piercing the clavipectoral fascia?","options":["Basilic vein","Axillary vein","Subclavian vein directly","Brachial vein"],"correct_index":1,"explanation":"After ascending in the deltopectoral groove and passing through the deltopectoral (clavipectoral) triangle, the cephalic vein pierces the costocoracoid membrane to drain into the axillary vein."},
{"topic":"Veins - Basilic Vein","question":"The basilic vein arises from the ulnar side of the dorsal venous network and, in the arm, pierces the deep fascia to run alongside which structure before becoming the axillary vein?","options":["Brachial artery, becoming axillary vein at the lower border of teres major","Cephalic vein directly","Radial artery","Profunda brachii artery"],"correct_index":0,"explanation":"The basilic vein pierces the deep fascia around the middle of the arm to join the brachial veins accompanying the brachial artery, and becomes the axillary vein at the lower border of teres major."},
{"topic":"Veins - Median Cubital Vein","question":"The median cubital vein, commonly used for venipuncture, connects which two superficial veins in the cubital fossa region?","options":["Cephalic and basilic veins","Basilic vein and brachial vein","Cephalic vein and axillary vein","Median antebrachial and basilic veins only"],"correct_index":0,"explanation":"The median cubital vein obliquely connects the cephalic vein (laterally) to the basilic vein (medially) in the roof of the cubital fossa, and is the preferred site for venipuncture and IV cannulation."},
{"topic":"Veins - Median Cubital Vein","question":"Which nerve lies in close relation deep to the median cubital vein, making its injury a risk during careless venipuncture?","options":["Median nerve","Medial cutaneous nerve of forearm / brachial fascia perforators, and rarely the median nerve if deep","Radial nerve","Ulnar nerve"],"correct_index":1,"explanation":"The median cubital vein lies superficial to the bicipital aponeurosis, which normally protects deeper structures like the brachial artery and median nerve; however, careless or deep needle insertion can still risk nearby cutaneous nerve branches."},
{"topic":"Veins - Deep Veins","question":"In the upper limb, the deep veins typically:","options":["Are single vessels accompanying each artery","Occur in pairs (venae comitantes) alongside the corresponding artery, especially in smaller vessels","Are absent below the elbow","Only exist in the hand"],"correct_index":1,"explanation":"Deep veins of the upper limb (radial, ulnar, brachial veins) commonly exist as paired venae comitantes running alongside their corresponding arteries, especially in the forearm and distal arm."},
{"topic":"Veins - Axillary Vein","question":"The axillary vein is formed by the union of the brachial veins and basilic vein at the lower border of which muscle, and continues as the subclavian vein at the outer border of the first rib?","options":["Pectoralis minor","Teres major","Latissimus dorsi","Subscapularis"],"correct_index":1,"explanation":"The axillary vein begins at the lower border of teres major (union of basilic vein and brachial veins) and becomes the subclavian vein at the outer border of the first rib."},
{"topic":"Cutaneous Nerves","question":"The skin over the point of the shoulder (tip of acromion) is supplied mainly by which nerve, derived from the cervical plexus?","options":["Axillary nerve (via its cutaneous branch)","Supraclavicular nerves","Intercostobrachial nerve","Suprascapular nerve"],"correct_index":1,"explanation":"The supraclavicular nerves, branches of the cervical plexus (C3, C4), supply skin over the point of the shoulder and upper chest, explaining why shoulder pain can sometimes be referred from the neck (e.g., diaphragmatic irritation)."},
{"topic":"Cutaneous Nerves","question":"The skin over the lower half of the deltoid muscle ('regimental badge area') is supplied by which nerve, useful for testing axillary nerve function?","options":["Upper lateral cutaneous nerve of arm (from axillary nerve)","Lower lateral cutaneous nerve of arm (from radial nerve)","Intercostobrachial nerve","Medial cutaneous nerve of arm"],"correct_index":0,"explanation":"The upper lateral cutaneous nerve of the arm, a branch of the axillary nerve, supplies the skin over the lower deltoid ('regimental badge' area) and is tested clinically to assess axillary nerve integrity after shoulder dislocation or surgical neck fracture."},
{"topic":"Cutaneous Nerves","question":"The medial cutaneous nerve of the forearm is a branch of which cord/structure of the brachial plexus?","options":["Lateral cord","Posterior cord","Medial cord","Upper trunk"],"correct_index":2,"explanation":"The medial cutaneous nerve of the forearm arises from the medial cord of the brachial plexus (C8, T1) and supplies skin on the medial side of the forearm."},
{"topic":"Cutaneous Nerves","question":"The lateral cutaneous nerve of the forearm is the continuation of which nerve after it supplies the anterior arm muscles?","options":["Median nerve","Ulnar nerve","Musculocutaneous nerve","Radial nerve"],"correct_index":2,"explanation":"The musculocutaneous nerve, after supplying coracobrachialis, biceps brachii, and brachialis, continues as the lateral cutaneous nerve of the forearm, supplying skin on the lateral aspect of the forearm."},
{"topic":"Cutaneous Nerves","question":"The posterior cutaneous nerve of the forearm, supplying skin on the extensor aspect of the forearm, arises from which nerve?","options":["Ulnar nerve","Median nerve","Radial nerve","Axillary nerve"],"correct_index":2,"explanation":"The posterior cutaneous nerve of the forearm is a branch of the radial nerve, given off in the arm before the radial nerve reaches the elbow, supplying the posterior forearm skin."},
{"topic":"Cutaneous Nerves","question":"The palmar cutaneous branch of the median nerve, which supplies skin over the thenar eminence, arises where relative to the flexor retinaculum, explaining why carpal tunnel syndrome typically spares this area?","options":["It arises distal to the flexor retinaculum, deep to it","It arises proximal to the flexor retinaculum and passes superficial to it","It passes through the carpal tunnel with the main median nerve trunk","It does not exist; the ulnar nerve supplies this area instead"],"correct_index":1,"explanation":"The palmar cutaneous branch of the median nerve arises proximal to the wrist and passes superficial to the flexor retinaculum (not through the carpal tunnel), which is why sensation over the thenar eminence is typically preserved in carpal tunnel syndrome."},
{"topic":"Dermatomes","question":"The dermatome supplying the tip of the thumb typically corresponds to which spinal segment?","options":["C5","C6","C7","C8"],"correct_index":1,"explanation":"The thumb (and lateral forearm) dermatome corresponds to C6, useful in localizing cervical nerve root lesions, following the classic dermatome map down the lateral arm to the thumb."},
{"topic":"Dermatomes","question":"The dermatome supplying the little finger typically corresponds to which spinal segment?","options":["C6","C7","C8","T1"],"correct_index":2,"explanation":"The little finger (and medial hand) dermatome corresponds to C8, distinguishing it from the medial forearm and arm (C8/T1 boundary area) and axilla (T2)."},
{"topic":"Dermatomes","question":"The dermatome over the medial side of the arm and axilla (T2) is clinically relevant because it overlaps with which cutaneous nerve territory important in mastectomy?","options":["Supraclavicular nerve","Intercostobrachial nerve (T2)","Median cutaneous nerve of forearm","Radial nerve territory"],"correct_index":1,"explanation":"The intercostobrachial nerve (lateral cutaneous branch of the 2nd intercostal/T2 nerve) supplies the medial arm and axilla; it is often sacrificed or injured during axillary lymph node dissection in mastectomy, leading to sensory changes in this dermatome."},
{"topic":"Muscles - Shoulder Girdle","question":"Which nerve provides the main motor supply to the trapezius muscle?","options":["Vagus nerve (CN X)","Spinal accessory nerve (CN XI)","Facial nerve (CN VII)","Dorsal scapular nerve"],"correct_index":1,"explanation":"Trapezius (and sternocleidomastoid) receive their motor supply from the spinal accessory nerve (CN XI), with proprioceptive fibers carried by C3 and C4 through the cervical plexus."},
{"topic":"Muscles - Shoulder Girdle","question":"The deltoid muscle is supplied by which nerve?","options":["Suprascapular nerve","Axillary nerve","Radial nerve","Musculocutaneous nerve"],"correct_index":1,"explanation":"The axillary nerve (C5, C6) winds around the surgical neck of the humerus and supplies both deltoid and teres minor; its injury causes flattening of the shoulder contour."},
{"topic":"Muscles - Shoulder Girdle","question":"Which muscle initiates the first 15 degrees of arm abduction before the deltoid takes over the main effort?","options":["Infraspinatus","Supraspinatus","Teres minor","Subscapularis"],"correct_index":1,"explanation":"Supraspinatus initiates abduction from 0-15 degrees; deltoid then continues the movement up to about 90 degrees, with serratus anterior and trapezius contributing to further overhead abduction."},
{"topic":"Muscles - Shoulder Girdle","question":"Which rotator cuff muscle acts as the main medial (internal) rotator of the shoulder joint?","options":["Supraspinatus","Infraspinatus","Teres minor","Subscapularis"],"correct_index":3,"explanation":"Subscapularis produces medial rotation of the humerus; supraspinatus mainly abducts, while infraspinatus and teres minor are lateral rotators."},
{"topic":"Muscles - Shoulder Girdle","question":"Rhomboid major and minor muscles are supplied by:","options":["Long thoracic nerve","Dorsal scapular nerve","Suprascapular nerve","Axillary nerve"],"correct_index":1,"explanation":"The dorsal scapular nerve (C5) supplies rhomboid major, rhomboid minor, and contributes to levator scapulae."},
{"topic":"Muscles - Shoulder Girdle","question":"Winging of the scapula results from paralysis of serratus anterior due to injury of which nerve?","options":["Dorsal scapular nerve","Suprascapular nerve","Long thoracic nerve","Thoracodorsal nerve"],"correct_index":2,"explanation":"The long thoracic nerve (C5, C6, C7) supplies serratus anterior; injury (e.g., during mastectomy/axillary surgery) causes winging of the scapula, most obvious when pushing against a wall."},
{"topic":"Muscles - Shoulder Girdle","question":"Which muscle protracts the scapula and rotates the glenoid cavity upward, essential for full overhead abduction of the arm beyond 90 degrees?","options":["Trapezius alone","Serratus anterior (with trapezius)","Rhomboid major","Levator scapulae"],"correct_index":1,"explanation":"Serratus anterior protracts the scapula and, together with trapezius, rotates the scapula so the glenoid cavity faces upward, enabling abduction of the arm above 90 degrees."},
{"topic":"Muscles - Shoulder Girdle","question":"Latissimus dorsi is supplied by which nerve?","options":["Thoracodorsal nerve","Long thoracic nerve","Dorsal scapular nerve","Lower subscapular nerve"],"correct_index":0,"explanation":"The thoracodorsal nerve, a branch of the posterior cord, supplies latissimus dorsi, which extends, adducts, and medially rotates the arm."},
{"topic":"Muscles - Shoulder Girdle","question":"Supraspinatus and infraspinatus are both supplied by which nerve?","options":["Axillary nerve","Suprascapular nerve","Dorsal scapular nerve","Long thoracic nerve"],"correct_index":1,"explanation":"The suprascapular nerve (from the upper trunk, C5-C6) passes through the suprascapular notch to supply both supraspinatus and infraspinatus."},
{"topic":"Muscles - Shoulder Girdle","question":"Subscapularis muscle is innervated by:","options":["Upper and lower subscapular nerves","Axillary nerve only","Suprascapular nerve","Thoracodorsal nerve"],"correct_index":0,"explanation":"Subscapularis receives supply from both the upper and lower subscapular nerves, branches of the posterior cord of the brachial plexus."},
{"topic":"Muscles - Arm","question":"Biceps brachii is supplied by:","options":["Radial nerve","Musculocutaneous nerve","Median nerve","Axillary nerve"],"correct_index":1,"explanation":"The musculocutaneous nerve supplies all three anterior arm muscles: biceps brachii, brachialis, and coracobrachialis."},
{"topic":"Muscles - Arm","question":"Which muscle is regarded as the most powerful supinator of the forearm, especially when the elbow is flexed?","options":["Supinator","Biceps brachii","Brachioradialis","Pronator teres"],"correct_index":1,"explanation":"Biceps brachii is the most powerful supinator, particularly with the elbow flexed to 90 degrees; the supinator muscle assists mainly with the elbow extended."},
{"topic":"Muscles - Arm","question":"The long head of biceps brachii arises from which structure?","options":["Coracoid process of scapula","Supraglenoid tubercle of scapula","Infraglenoid tubercle of scapula","Glenoid labrum inferiorly"],"correct_index":1,"explanation":"The long head of biceps arises from the supraglenoid tubercle of the scapula, running through the shoulder joint capsule; the short head arises from the coracoid process."},
{"topic":"Muscles - Arm","question":"Brachialis muscle is chiefly supplied by which nerve, with a small additional contribution from another nerve?","options":["Median nerve; ulnar contribution","Musculocutaneous nerve; radial nerve contribution","Ulnar nerve; median contribution","Radial nerve; axillary contribution"],"correct_index":1,"explanation":"Brachialis is mainly supplied by the musculocutaneous nerve with a small additional twig from the radial nerve, making it a muscle with dual innervation; it is the main flexor of the elbow joint."},
{"topic":"Muscles - Arm","question":"Coracobrachialis muscle produces which movement(s) at the shoulder, and is pierced by which nerve?","options":["Abduction and lateral rotation; axillary nerve","Flexion and adduction; musculocutaneous nerve","Extension and medial rotation; radial nerve","Abduction and medial rotation; median nerve"],"correct_index":1,"explanation":"Coracobrachialis flexes and adducts the arm at the shoulder and is pierced by the musculocutaneous nerve as it enters the anterior compartment of the arm."},
{"topic":"Muscles - Arm","question":"All three heads of triceps brachii are supplied by:","options":["Axillary nerve","Musculocutaneous nerve","Radial nerve","Ulnar nerve"],"correct_index":2,"explanation":"The radial nerve supplies all three heads (long, lateral, medial) of triceps brachii as it courses through the posterior compartment of the arm in the spiral groove."},
{"topic":"Muscles - Arm","question":"The long head of triceps brachii originates from which structure?","options":["Supraglenoid tubercle of scapula","Infraglenoid tubercle of scapula","Lateral border of scapula","Posterior surface of humerus"],"correct_index":1,"explanation":"The long head of triceps arises from the infraglenoid tubercle of the scapula; the lateral and medial heads arise from the posterior humeral shaft above and below the spiral groove, respectively."},
{"topic":"Muscles - Arm","question":"Which arm muscle can also weakly flex the elbow joint and lies posteriorly, blending with the medial head of triceps at the elbow?","options":["Anconeus","Brachioradialis","Supinator","Pronator teres"],"correct_index":0,"explanation":"Anconeus, a small muscle at the posterolateral aspect of the elbow, assists triceps in extension and is thought to stabilize the elbow joint during movement; it is supplied by the radial nerve."},
{"topic":"Muscles - Forearm Flexors","question":"Pronator teres is supplied by which nerve, which passes between its two heads?","options":["Ulnar nerve","Median nerve","Anterior interosseous nerve","Radial nerve"],"correct_index":1,"explanation":"Pronator teres, part of the superficial flexor group, is supplied directly by the median nerve, which passes between its humeral and ulnar heads as it enters the forearm."},
{"topic":"Muscles - Forearm Flexors","question":"Which forearm flexor muscle is supplied by the ulnar nerve, unlike most other superficial flexors?","options":["Flexor carpi radialis","Palmaris longus","Flexor carpi ulnaris","Flexor digitorum superficialis"],"correct_index":2,"explanation":"Flexor carpi ulnaris is supplied by the ulnar nerve, making it (along with the medial half of flexor digitorum profundus) an exception among the flexor forearm muscles, most of which are median-innervated."},
{"topic":"Muscles - Forearm Flexors","question":"Flexor digitorum profundus receives its nerve supply from which nerve(s)?","options":["Median nerve only","Ulnar nerve only","Median nerve (lateral half, via anterior interosseous nerve) and ulnar nerve (medial half)","Radial nerve"],"correct_index":2,"explanation":"Flexor digitorum profundus has dual nerve supply: the lateral half (index and middle fingers) via the anterior interosseous branch of the median nerve, and the medial half (ring and little fingers) via the ulnar nerve."},
{"topic":"Muscles - Forearm Flexors","question":"Flexor pollicis longus is supplied by:","options":["Ulnar nerve","Anterior interosseous nerve (branch of median)","Posterior interosseous nerve","Musculocutaneous nerve"],"correct_index":1,"explanation":"Flexor pollicis longus, a deep flexor compartment muscle, is supplied by the anterior interosseous nerve, a branch of the median nerve."},
{"topic":"Muscles - Forearm Flexors","question":"Pronator quadratus is innervated by:","options":["Median nerve proper","Anterior interosseous nerve","Ulnar nerve","Posterior interosseous nerve"],"correct_index":1,"explanation":"Pronator quadratus, the deepest forearm muscle, is supplied by the anterior interosseous nerve (a branch of the median nerve), the same nerve supplying flexor pollicis longus and the lateral half of FDP."},
{"topic":"Muscles - Forearm Flexors","question":"Flexor digitorum superficialis is supplied by which nerve?","options":["Ulnar nerve","Median nerve","Anterior interosseous nerve exclusively","Radial nerve"],"correct_index":1,"explanation":"Flexor digitorum superficialis, part of the intermediate layer of the flexor forearm muscles, is supplied by the median nerve."},
{"topic":"Muscles - Forearm Flexors","question":"Palmaris longus, though frequently absent as a normal variant, is supplied by which nerve?","options":["Ulnar nerve","Median nerve","Radial nerve","Anterior interosseous nerve"],"correct_index":1,"explanation":"Palmaris longus, a superficial flexor group muscle often absent in about 10-15% of people, is supplied by the median nerve when present."},
{"topic":"Muscles - Forearm Flexors","question":"Flexor carpi radialis inserts into the base of which metacarpal(s)?","options":["Base of 2nd (and sometimes 3rd) metacarpal","Base of 5th metacarpal","Pisiform bone","Base of 1st metacarpal"],"correct_index":0,"explanation":"Flexor carpi radialis inserts mainly onto the base of the 2nd metacarpal (with a slip sometimes to the 3rd), and is supplied by the median nerve."},
{"topic":"Muscles - Forearm Flexors","question":"Which structure passes between the two heads of origin (humeral and ulnar) of flexor digitorum superficialis, along with the median nerve?","options":["Ulnar artery","Radial artery","Anterior interosseous artery","Median nerve enters here but no artery passes between the heads"],"correct_index":0,"explanation":"The ulnar artery, along with the median nerve, passes between the humeral and ulnar heads of flexor digitorum superficialis as it descends into the forearm."},
{"topic":"Muscles - Forearm Extensors","question":"The supinator muscle is supplied by:","options":["Superficial branch of radial nerve","Posterior interosseous (deep branch of radial) nerve","Median nerve","Musculocutaneous nerve"],"correct_index":1,"explanation":"Supinator is supplied by the posterior interosseous nerve, the deep terminal branch of the radial nerve, which pierces through the substance of the muscle."},
{"topic":"Muscles - Forearm Extensors","question":"Brachioradialis, though located in the extensor compartment of the forearm, functions mainly as a:","options":["Extensor of wrist","Flexor of elbow","Pronator of forearm","Extensor of fingers"],"correct_index":1,"explanation":"Despite lying in the extensor (posterior) compartment and being radial nerve supplied, brachioradialis functions mainly as a flexor of the elbow joint, especially in the mid-prone position."},
{"topic":"Muscles - Forearm Extensors","question":"Extensor digitorum of the forearm is supplied by:","options":["Radial nerve trunk","Posterior interosseous nerve","Superficial radial nerve","Median nerve"],"correct_index":1,"explanation":"Extensor digitorum, part of the superficial extensor group, is supplied by the posterior interosseous nerve (the deep branch of the radial nerve)."},
{"topic":"Muscles - Forearm Extensors","question":"Extensor carpi ulnaris is innervated by which nerve, despite its name relating to the ulnar side of the forearm?","options":["Ulnar nerve","Posterior interosseous nerve","Median nerve","Radial nerve trunk directly"],"correct_index":1,"explanation":"Extensor carpi ulnaris is innervated by the posterior interosseous nerve (a branch of the radial nerve), not the ulnar nerve, despite its anatomical position and name."},
{"topic":"Muscles - Hand","question":"The three thenar muscles (abductor pollicis brevis, flexor pollicis brevis, opponens pollicis) are supplied by:","options":["Ulnar nerve","Recurrent (thenar motor) branch of median nerve","Posterior interosseous nerve","Deep branch of ulnar nerve"],"correct_index":1,"explanation":"The recurrent (thenar motor) branch of the median nerve, sometimes called the 'million dollar nerve' due to its clinical importance, supplies all three thenar muscles."},
{"topic":"Muscles - Hand","question":"Adductor pollicis, though located in the thenar region, is supplied by which nerve?","options":["Median nerve","Deep branch of ulnar nerve","Superficial branch of ulnar nerve","Anterior interosseous nerve"],"correct_index":1,"explanation":"Adductor pollicis is an intrinsic hand muscle supplied by the deep branch of the ulnar nerve, not the median nerve, despite lying near the other thenar muscles."},
{"topic":"Muscles - Hand","question":"The 1st and 2nd lumbrical muscles of the hand are supplied by which nerve, unlike the 3rd and 4th lumbricals?","options":["Median nerve","Deep branch of ulnar nerve","Superficial branch of radial nerve","Anterior interosseous nerve"],"correct_index":0,"explanation":"The 1st and 2nd lumbricals are supplied by the median nerve, while the 3rd and 4th lumbricals are supplied by the deep branch of the ulnar nerve."},
{"topic":"Muscles - Hand","question":"The dorsal interossei of the hand primarily produce which movement of the fingers at the metacarpophalangeal joints?","options":["Adduction toward the axial line (midline of the middle finger)","Abduction away from the axial line (midline)","Pure flexion at the interphalangeal joints","Pure extension at the metacarpophalangeal joints"],"correct_index":1,"explanation":"Dorsal interossei ABduct the fingers (mnemonic: DAB = Dorsals ABduct), while palmar interossei ADduct them (mnemonic: PAD = Palmars ADduct); both groups are supplied by the deep branch of the ulnar nerve."},
{"topic":"Brachial Plexus - Formation","question":"The brachial plexus is formed by the ventral rami of which spinal nerves?","options":["C4-C8","C5-T1","C3-C7","C6-T2"],"correct_index":1,"explanation":"The brachial plexus is formed by the ventral rami of C5, C6, C7, C8, and T1 spinal nerves, occasionally with minor contributions from C4 (prefixed plexus) or T2 (postfixed plexus)."},
{"topic":"Brachial Plexus - Mnemonic","question":"The mnemonic 'Randy Travis Drinks Cold Beer' is often used to remember the sequence of parts of the brachial plexus. What does the 'D' represent?","options":["Deltoid","Divisions","Dorsal scapular nerve","Distal branches"],"correct_index":1,"explanation":"The mnemonic represents Roots, Trunks, Divisions, Cords, Branches, the sequential organization of the brachial plexus from proximal (spine) to distal (limb)."},
{"topic":"Brachial Plexus - Trunks","question":"The upper trunk of the brachial plexus is formed by union of which two roots?","options":["C5 and C6","C6 and C7","C7 and C8","C8 and T1"],"correct_index":0,"explanation":"The upper trunk is formed by union of the C5 and C6 roots; this is the trunk injured in Erb-Duchenne palsy."},
{"topic":"Brachial Plexus - Trunks","question":"The middle trunk of the brachial plexus is formed by:","options":["Union of C5 and C6","Continuation of the C7 root alone","Union of C7 and C8","Union of C6 and C7"],"correct_index":1,"explanation":"Unlike the upper and lower trunks (each formed by union of two roots), the middle trunk is simply the direct continuation of the C7 root."},
{"topic":"Brachial Plexus - Trunks","question":"The lower trunk of the brachial plexus is formed by union of which roots?","options":["C5 and C6","C6 alone","C7 and C8","C8 and T1"],"correct_index":3,"explanation":"The lower trunk is formed by union of the C8 and T1 roots; this is the trunk injured in Klumpke's paralysis."},
{"topic":"Brachial Plexus - Divisions","question":"Each trunk of the brachial plexus splits, behind the clavicle, into:","options":["Medial and lateral divisions","Anterior and posterior divisions","Superior and inferior divisions","Superficial and deep divisions"],"correct_index":1,"explanation":"Each of the three trunks divides into an anterior and a posterior division behind the clavicle; these divisions then recombine to form the three cords of the brachial plexus."},
{"topic":"Brachial Plexus - Cords","question":"The lateral cord of the brachial plexus is formed by the union of:","options":["Posterior divisions of all three trunks","Anterior divisions of the upper and middle trunks","Anterior division of the lower trunk only","Anterior divisions of the middle and lower trunks"],"correct_index":1,"explanation":"The lateral cord is formed by union of the anterior divisions of the upper and middle trunks, carrying fibers mainly from C5, C6, and C7."},
{"topic":"Brachial Plexus - Cords","question":"The medial cord of the brachial plexus is simply a continuation of:","options":["The anterior division of the lower trunk","Posterior divisions of all trunks","Anterior divisions of the upper and middle trunks","Posterior division of the lower trunk"],"correct_index":0,"explanation":"The medial cord is the direct continuation of the anterior division of the lower trunk, carrying fibers mainly from C8 and T1."},
{"topic":"Brachial Plexus - Cords","question":"The posterior cord of the brachial plexus is formed by union of:","options":["Anterior divisions of all three trunks","Posterior divisions of all three trunks","The anterior division of the upper trunk with the posterior division of the lower trunk","Posterior divisions of the upper and middle trunks only"],"correct_index":1,"explanation":"The posterior cord is formed by union of the posterior divisions of all three trunks (upper, middle, and lower), containing fibers from C5 through C8."},
{"topic":"Brachial Plexus - Cords","question":"The three cords of the brachial plexus (lateral, medial, posterior) are named according to their relationship to which structure?","options":["First rib","Clavicle","Axillary artery","Coracoid process"],"correct_index":2,"explanation":"The lateral, medial, and posterior cords are named according to their position relative to the second part of the axillary artery, which they surround."},
{"topic":"Brachial Plexus - Branches","question":"The dorsal scapular nerve, which supplies the rhomboids, arises from which part of the brachial plexus?","options":["Upper trunk","Root (C5)","Lateral cord","Posterior cord"],"correct_index":1,"explanation":"The dorsal scapular nerve arises directly from the C5 root, before the roots unite into trunks, and passes through scalenus medius to reach the rhomboids."},
{"topic":"Brachial Plexus - Branches","question":"The long thoracic nerve (nerve to serratus anterior) arises from which part of the brachial plexus?","options":["Roots C5, C6, C7","Upper trunk","Posterior cord","Lateral cord"],"correct_index":0,"explanation":"The long thoracic nerve arises directly from the roots C5, C6, and C7, and descends along the surface of serratus anterior, which it supplies."},
{"topic":"Brachial Plexus - Branches","question":"The suprascapular nerve arises from which part of the brachial plexus?","options":["Lateral cord","Upper trunk","Posterior cord","Root C5 directly"],"correct_index":1,"explanation":"The suprascapular nerve arises from the upper trunk (C5, C6) and passes through the suprascapular notch to supply supraspinatus and infraspinatus."},
{"topic":"Brachial Plexus - Branches","question":"Which of the following is NOT a branch of the posterior cord of the brachial plexus?","options":["Axillary nerve","Radial nerve","Thoracodorsal nerve","Musculocutaneous nerve"],"correct_index":3,"explanation":"Musculocutaneous nerve arises from the lateral cord, not the posterior cord. Axillary, radial, and thoracodorsal (nerve to latissimus dorsi) nerves are all branches of the posterior cord, along with upper and lower subscapular nerves."},
{"topic":"Brachial Plexus - Branches","question":"The medial and lateral pectoral nerves, supplying pectoralis major and minor, arise respectively from which cords?","options":["Medial pectoral from lateral cord; lateral pectoral from medial cord","Medial pectoral from medial cord; lateral pectoral from lateral cord","Both arise from the posterior cord","Both arise from the upper trunk"],"correct_index":1,"explanation":"Despite the potentially confusing names, the medial pectoral nerve arises from the medial cord and the lateral pectoral nerve arises from the lateral cord of the brachial plexus."},
{"topic":"Nerves - Median Nerve","question":"The median nerve is formed by the union of a lateral root from the lateral cord and a medial root from the:","options":["Medial cord","Posterior cord","Upper trunk","Axillary nerve"],"correct_index":0,"explanation":"The median nerve is formed by two roots: a lateral root from the lateral cord (C5-C7) and a medial root from the medial cord (C8, T1), which unite anterior to the third part of the axillary artery."},
{"topic":"Nerves - Ulnar Nerve","question":"The ulnar nerve is a direct continuation of which cord of the brachial plexus?","options":["Lateral cord","Posterior cord","Medial cord","Upper trunk"],"correct_index":2,"explanation":"The ulnar nerve is the direct continuation of the medial cord (C8, T1) of the brachial plexus, without receiving a contribution from another cord."},
{"topic":"Nerves - Musculocutaneous Nerve","question":"The musculocutaneous nerve is a branch of the:","options":["Medial cord","Posterior cord","Lateral cord","Upper trunk"],"correct_index":2,"explanation":"The musculocutaneous nerve arises from the lateral cord (C5, C6, C7) and supplies coracobrachialis, biceps brachii, and brachialis before continuing as the lateral cutaneous nerve of the forearm."},
{"topic":"Nerves - Musculocutaneous Nerve","question":"The musculocutaneous nerve typically pierces which muscle to enter the anterior compartment of the arm?","options":["Biceps brachii","Coracobrachialis","Brachialis","Triceps brachii"],"correct_index":1,"explanation":"The musculocutaneous nerve pierces coracobrachialis to enter and run within the anterior compartment of the arm, between biceps brachii and brachialis."},
{"topic":"Nerves - Axillary Nerve","question":"The axillary nerve is closely accompanied by which artery as it winds around the surgical neck of the humerus through the quadrangular space?","options":["Profunda brachii artery","Posterior circumflex humeral artery","Anterior circumflex humeral artery","Suprascapular artery"],"correct_index":1,"explanation":"The axillary nerve travels with the posterior circumflex humeral artery through the quadrangular space around the surgical neck of the humerus; the profunda brachii artery instead accompanies the radial nerve."},
{"topic":"Nerves - Axillary Nerve","question":"The axillary nerve supplies which two muscles directly?","options":["Supraspinatus and infraspinatus","Deltoid and teres minor","Teres major and latissimus dorsi","Subscapularis and teres minor"],"correct_index":1,"explanation":"The axillary nerve supplies deltoid and teres minor, and also gives the upper lateral cutaneous nerve of the arm to skin over the lower deltoid ('regimental badge' area)."},
{"topic":"Nerves - Radial Nerve","question":"The radial nerve winds around the humerus within the:","options":["Bicipital groove","Spiral (radial) groove","Supracondylar ridge","Cubital fossa"],"correct_index":1,"explanation":"The radial nerve courses through the spiral (radial) groove on the posterior surface of the humeral shaft along with the profunda brachii artery, making it vulnerable to injury in midshaft humeral fractures."},
{"topic":"Nerves - Radial Nerve","question":"Near the elbow, the radial nerve divides into which two terminal branches?","options":["Anterior and posterior interosseous nerves","A superficial (cutaneous) branch and a deep branch (posterior interosseous nerve)","Median and ulnar branches","Medial and lateral branches"],"correct_index":1,"explanation":"Near the elbow, the radial nerve divides into a superficial (sensory) branch that continues down the forearm and a deep branch (posterior interosseous nerve) that pierces the supinator to supply the extensor muscles."},
{"topic":"Nerves - Ulnar Nerve","question":"The ulnar nerve is particularly vulnerable to injury at the elbow because it passes:","options":["Through the cubital fossa","Behind the medial epicondyle of the humerus","In front of the lateral epicondyle","Through the substance of the supinator muscle"],"correct_index":1,"explanation":"The ulnar nerve passes superficially behind the medial epicondyle of the humerus (the 'funny bone'), making it prone to injury from direct trauma or fracture at this site."},
{"topic":"Nerves - Median Nerve","question":"'Hand of benediction' seen on attempted fist-making is a feature of a high injury to which nerve, near the elbow/proximal forearm?","options":["Ulnar nerve","Radial nerve","Median nerve","Axillary nerve"],"correct_index":2,"explanation":"A high median nerve injury paralyzes the lateral two lumbricals and the long flexors of the index and middle fingers, so on attempted fist-making the index and middle fingers remain extended while the ring and little fingers flex, producing the 'hand of benediction'."},
{"topic":"Nerves - Ulnar Nerve","question":"The 'ulnar paradox' refers to the observation that:","options":["Claw hand deformity is more marked in a distal (wrist-level) ulnar nerve lesion than in a proximal (elbow-level) lesion","Claw hand occurs only in high lesions","Ulnar nerve injury never causes clawing of fingers","Sensory loss is greater in high lesions than in low lesions"],"correct_index":0,"explanation":"In a proximal (high) ulnar nerve lesion, the medial half of flexor digitorum profundus is also paralyzed, reducing the flexor pull on the ring and little fingers, so clawing is paradoxically less severe than in a distal (low, wrist-level) lesion where FDP function remains intact."},
{"topic":"Nerves - Cutaneous Innervation","question":"The ulnar nerve supplies cutaneous sensation to which part of the hand?","options":["Lateral 3.5 fingers on the palmar aspect","Medial one and a half fingers on both palmar and dorsal aspects","The entire dorsum of the hand","Thumb and index finger only"],"correct_index":1,"explanation":"The ulnar nerve supplies sensation to the medial one and a half fingers (little finger and medial half of ring finger) on both the palmar and dorsal surfaces of the hand; the median nerve supplies the lateral 3.5 fingers palmarly."},
{"topic":"Nerves - Median Nerve","question":"Which forearm muscle is the exception NOT supplied by the median nerve among these superficial flexors?","options":["Pronator teres","Flexor digitorum superficialis","Flexor carpi ulnaris","Flexor carpi radialis"],"correct_index":2,"explanation":"Flexor carpi ulnaris is supplied by the ulnar nerve, unlike pronator teres, flexor digitorum superficialis, and flexor carpi radialis, all of which are median nerve-supplied."},
{"topic":"Nerves - Ulnar Nerve","question":"The ulnar nerve enters the palm superficial to the flexor retinaculum by passing through which structure, sparing it from carpal tunnel compression?","options":["Carpal tunnel along with the median nerve","Guyon's canal (ulnar canal)","The anatomical snuffbox","The extensor retinaculum"],"correct_index":1,"explanation":"The ulnar nerve and artery pass into the hand through Guyon's canal, superficial to the flexor retinaculum, distinct from the carpal tunnel; this is why the ulnar nerve is not typically compressed in classic carpal tunnel syndrome."},
{"topic":"Nerves - Radial Nerve","question":"The posterior interosseous nerve (deep branch of the radial nerve) passes through which muscle, making it vulnerable in certain forearm fractures/dislocations?","options":["Pronator teres","Supinator","Brachioradialis","Flexor digitorum superficialis"],"correct_index":1,"explanation":"The posterior interosseous nerve passes through the substance of the supinator muscle (through the 'arcade of Frohse'), making it vulnerable to compression or injury in radial head fractures/dislocations."},
{"topic":"Nerves - Cutaneous","question":"The dorsum of the hand over the first web space (between thumb and index finger) is supplied mainly by which nerve, useful clinically to test radial nerve sensory function?","options":["Median nerve","Ulnar nerve","Superficial branch of radial nerve","Musculocutaneous nerve"],"correct_index":2,"explanation":"The superficial branch of the radial nerve supplies the dorsum of the hand including the first web space, and testing sensation here helps assess radial nerve integrity, e.g., after a humeral shaft fracture."},
{"topic":"Vessels - Subclavian Artery","question":"The right subclavian artery typically arises from:","options":["The aortic arch directly","The brachiocephalic (innominate) trunk","The common carotid artery","The axillary artery"],"correct_index":1,"explanation":"The right subclavian artery arises from the brachiocephalic trunk, while the left subclavian artery arises directly from the arch of the aorta."},
{"topic":"Vessels - Subclavian Artery","question":"The subclavian artery is divided into three parts based on its relationship to which muscle?","options":["Pectoralis minor","Scalenus anterior","Subclavius","Sternocleidomastoid"],"correct_index":1,"explanation":"The subclavian artery is divided into three parts in relation to scalenus anterior: the first part medial to it, the second part behind it, and the third part lateral to it."},
{"topic":"Vessels - Axillary Artery","question":"The axillary artery begins as a continuation of the subclavian artery at the outer border of which structure?","options":["Clavicle","First rib","Coracoid process","Manubrium sterni"],"correct_index":1,"explanation":"The axillary artery begins at the outer border of the first rib (as a continuation of the subclavian artery) and ends at the lower border of teres major, where it becomes the brachial artery."},
{"topic":"Vessels - Axillary Artery","question":"The axillary artery is divided into three parts by which muscle crossing it?","options":["Pectoralis major","Pectoralis minor","Subscapularis","Coracobrachialis"],"correct_index":1,"explanation":"Pectoralis minor crosses the axillary artery and divides it into three parts: the first part proximal to the muscle, the second part behind it, and the third part distal to it."},
{"topic":"Vessels - Axillary Artery","question":"The first part of the axillary artery (proximal to pectoralis minor) gives off only one branch, which is the:","options":["Thoracoacromial artery","Lateral thoracic artery","Superior thoracic artery","Subscapular artery"],"correct_index":2,"explanation":"The first part of the axillary artery gives off only the superior thoracic artery. The thoracoacromial and lateral thoracic arteries arise from the second part; the subscapular, anterior and posterior circumflex humeral arteries arise from the third part."},
{"topic":"Vessels - Axillary Artery","question":"The second part of the axillary artery (behind pectoralis minor) gives off which two branches?","options":["Superior thoracic and subsc

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