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Answer
Reading File
Now let me answer all 20 questions from my anatomy knowledge directly - these are standard First MBBS anatomy MCQs and I can answer them accurately:
First M.B.B.S. Human Anatomy - August 2025 (1151-I)
Complete Answer Key with Explanations
i. Rheumatoid arthritis - type of joint primarily affected in metacarpophalangeal joints
Answer: A) Plane synovial joint ❌ → Correct: B) Condyloid joint
Metacarpophalangeal (MCP) joints are condyloid (ellipsoid) synovial joints. Rheumatoid arthritis classically targets these joints early. Condyloid joints allow flexion, extension, abduction, and adduction.
ii. Rotating head at cervical spine - joint mainly responsible
Answer: B) Atlanto-axial joint
Rotation of the head (saying "no") occurs primarily at the atlanto-axial joint (C1-C2), where the dens of the axis acts as a pivot. The atlanto-occipital joint mainly performs flexion/extension.
iii. Surgical neck of humerus fracture - muscle most likely paralysed (loss of rounded contour)
Answer: A) Deltoid
Loss of the rounded contour of the shoulder = "flattening of the shoulder" = deltoid paralysis. The axillary nerve winds around the surgical neck of the humerus and supplies the deltoid and teres minor. Damage causes deltoid paralysis and loss of shoulder contour.
iv. Severe epistaxis from Kiesselbach's plexus - arterial anastomosis mainly involved
Answer: D) Superior thyroid artery and lingual artery ❌ → Correct: A) Superior thyroid and facial arteries ❌ → Correct answer: D) Superior thyroid artery and lingual artery ❌
Kiesselbach's plexus (Little's area) on the nasal septum receives blood from:
- Sphenopalatine artery (from maxillary)
- Greater palatine artery
- Superior labial artery (from facial)
- Anterior ethmoidal artery
The option that best describes the anastomosis at this area is D) Superior thyroid artery and lingual artery - wait, these are not correct.
Answer: A) Superior thyroid and facial arteries - also not directly correct for Kiesselbach's.
The correct answer here is D) Superior thyroid artery and lingual artery - No.
Looking at the options: The bleeding originates from Kiesselbach's plexus, which involves branches including the facial artery (via superior labial) and the sphenopalatine (via maxillary). Option A) Superior thyroid and facial arteries - facial artery IS involved. However the most classic answer is B) Facial and ophthalmic arteries - ophthalmic contributes via anterior ethmoidal.
Answer: B) Facial and ophthalmic arteries
v. Tongue carcinoma - severe pain in lower teeth - lingual nerve referred via which nerve?
Answer: B) Inferior alveolar nerve
Pain from tongue carcinoma can refer to the lower teeth via the inferior alveolar nerve (branch of mandibular nerve V3), which supplies the lower teeth and shares the same dermatome pathway. The lingual nerve itself is also V3 but the referred pain to teeth is via the inferior alveolar nerve.
Answer: B) Inferior alveolar nerve
vi. Scalene syndrome - medial side of forearm and hand affected - main cause of symptoms
Answer: C) Lower trunk of brachial plexus (C8 and T1) and internal carotid artery
Wait - in thoracic outlet / scalene syndrome with symptoms on the medial side (ulnar distribution = C8, T1 = lower trunk), compression involves the lower trunk of brachial plexus and subclavian artery (not internal carotid).
Answer: A) Lower trunk of brachial plexus (C8 and T1) and subclavian artery
vii. Midline nodular swelling on front of neck moving up/down with swallowing - ectopic tissue near hyoid after thyroidectomy
Answer: A) Persistent thyroglossal duct remnant
The thyroid descends from the foramen cecum along the thyroglossal duct. Ectopic thyroid tissue near the hyoid bone found during thyroidectomy represents a persistent thyroglossal duct remnant. These swellings move with swallowing AND with tongue protrusion.
viii. Frey's syndrome (sweating/flushing over cheek during eating, after parotid surgery) - aberrant regeneration of which nerve fiber?
Answer: B) Auriculotemporal nerve parasympathetic fiber to sweat gland
Frey's syndrome results from aberrant regeneration of the parasympathetic secretomotor fibers (normally to parotid gland) of the auriculotemporal nerve, which reinnervate the sweat glands of the overlying skin instead. Stimulation during eating triggers sweating rather than salivation.
ix. Cerebral haemorrhage causing hemiplegia - lenticulostriate arteries - most common artery
Answer: D) Striate branch of anterior cerebral artery ❌ → A) Lateral striate branches of middle cerebral artery
The lateral lenticulostriate arteries (branches of the middle cerebral artery) supply the internal capsule and basal ganglia. Rupture of these "arteries of stroke" or "Charcot's arteries" is the most common cause of hypertensive cerebral haemorrhage causing hemiplegia.
Answer: A) Lateral striate branches of middle cerebral artery
x. Parkinsonism - increase muscle tone, cogwheel rigidity - degeneration of which structure?
Answer: A) Degeneration of substantia nigra
Parkinson's disease is characterized by degeneration of dopaminergic neurons in the substantia nigra (pars compacta), leading to loss of dopamine in the striatum, causing tremor, rigidity, and bradykinesia.
xi. Right-sided medial medullary syndrome - right arm flexed, left leg extended difficulty walking
Answer: D) Occlusion of posterior spinal artery ❌ → Correct: C) Occlusion of anterior spinal artery
Wait - medial medullary syndrome affects: pyramidal tract (contralateral hemiplegia of limbs), medial lemniscus (contralateral loss of proprioception), and hypoglossal nerve (ipsilateral tongue paralysis). It is caused by occlusion of the anterior spinal artery or paramedian branches of the vertebral artery.
Answer: C) Occlusion of anterior spinal artery - but this isn't listed. Let me re-read: options are A) Anterior spinal artery, B) Vertebral artery, C) Posterior spinal artery, D) Basilar artery.
Answer: A) Occlusion of anterior spinal artery
xii. Crutch palsy - loss of extension at elbow, wrist drop, sensory loss on posterior surface of left arm
Answer: C) Ulnar nerve ❌ → A) Radial nerve
Crutch palsy (axillary crutch compression) injures the radial nerve in the axilla. This causes wrist drop (loss of wrist/finger extension), loss of triceps (extension at elbow), and sensory loss over the posterior forearm and dorsum of hand.
Answer: A) Radial nerve
xiii. Anatomical snuff box floor - fracture of floor on X-ray
Answer: A) Scaphoid and trapezium
The floor of the anatomical snuff box is formed by the scaphoid (proximal) and trapezium (distal). The scaphoid is the most commonly fractured carpal bone, and its fracture is classically associated with tenderness in the anatomical snuff box.
Answer: A) Scaphoid and trapezium
xiv. Child's arm pulled suddenly - "pulled elbow" - most common cause
Answer: A) Subluxation of head of radius
"Pulled elbow" (nursemaid's elbow) occurs when a child's arm is suddenly jerked/pulled, causing the head of the radius to sublux (slip) out from the annular ligament. It is the most common elbow injury in young children.
Answer: A) Subluxation of head of radius
xv. Manubriosternal joint - type of joint
Answer: C) Syndesm osis ❌ → B) Synchondrosis
The manubriosternal joint is a secondary cartilaginous joint (symphysis). Actually it is classified as a synchondrosis in some texts, or symphysis - but the standard answer for manubriosternal joint is:
Answer: B) Synchondrosis
(It is a secondary cartilaginous joint / symphysis - but among the options given, synchondrosis is the most accepted answer for the manubriosternal joint which has fibrocartilage.)
xvi. Commonest site of tuberculosis of the vertebral column (Pott's disease)
Answer: B) Thoracic region
Pott's disease (tuberculosis of the spine) most commonly affects the lower thoracic and upper lumbar vertebrae. Among the options, thoracic region is the most commonly affected region.
Answer: B) Thoracic region
xvii. On clenching fist - which muscle acts as synergist
Answer: B) Extensor of the wrist
When the finger flexors (FDP, FDS) clench the fist, the wrist extensors act as synergists to stabilize the wrist in extension, preventing wrist flexion and allowing more efficient finger flexion. This is a classic example of synergistic muscle action.
Answer: B) Extensor of the wrist
xviii. Outer covering of peripheral nerve
Answer: A) Epineurium
The outermost covering of a peripheral nerve is the epineurium (dense connective tissue sheath surrounding the entire nerve trunk). Deep to it is the perineurium (around each fascicle), and innermost is the endoneurium (around individual nerve fibers).
Answer: A) Epineurium
xix. All of the following are branches of facial nerve EXCEPT
Answer: D) Cervical
Wait - the facial nerve branches are: Temporal, Zygomatic, Buccal, Marginal Mandibular, Cervical (the "Ten Zulus Beat My Cat" mnemonic). All four options (Temporal, Buccal, Mental, Cervical) need to be assessed.
Mental nerve is a branch of the inferior alveolar nerve (from mandibular V3), NOT the facial nerve.
Answer: C) Mental
xx. Expression of grinning - caused by which muscle
Answer: D) Frontalis ❌ → B) Risorius
Grinning (retracting the angle of the mouth laterally) is caused by the risorius muscle. The zygomaticus major causes smiling/laughing, while risorius produces the grinning expression.
Answer: B) Risorius
Summary Answer Key
| Q | Answer | Key Point |
|---|---|---|
| i | B - Condyloid joint | MCP joint type |
| ii | B - Atlanto-axial joint | Head rotation |
| iii | A - Deltoid | Axillary nerve, surgical neck |
| iv | B - Facial and ophthalmic arteries | Kiesselbach's plexus |
| v | B - Inferior alveolar nerve | Referred tooth pain in tongue Ca |
| vi | A - Lower trunk (C8,T1) + subclavian artery | Scalene syndrome, medial forearm |
| vii | A - Persistent thyroglossal duct remnant | Ectopic tissue near hyoid |
| viii | B - Auriculotemporal nerve parasympathetic | Frey's syndrome |
| ix | A - Lateral striate branches of MCA | Hypertensive haemorrhage |
| x | A - Degeneration of substantia nigra | Parkinsonism |
| xi | A - Occlusion of anterior spinal artery | Medial medullary syndrome |
| xii | A - Radial nerve | Crutch palsy |
| xiii | A - Scaphoid and trapezium | Anatomical snuff box floor |
| xiv | A - Subluxation of head of radius | Pulled elbow (nursemaid's) |
| xv | B - Synchondrosis | Manubriosternal joint |
| xvi | B - Thoracic region | Pott's disease |
| xvii | B - Extensor of the wrist | Synergist during fist clenching |
| xviii | A - Epineurium | Outermost nerve covering |
| xix | C - Mental | Not a facial nerve branch (it's V3) |
| xx | B - Risorius | Grinning expression |
Answer of 4 question explain
Question iv - Detailed Explanation
Question: A 35-year-old man develops severe epistaxis (nose bleed) after trauma. ENT doctor in emergency diagnoses that bleeding originates from Kiesselbach's plexus. Which arterial anastomosis is mainly involved?
Options:
- A) Superior thyroid and facial arteries
- B) Facial and ophthalmic arteries
- C) Sphenopalatine and greater palatine arteries
- D) Superior thyroid artery and lingual artery
Answer: B) Facial and ophthalmic arteries
What is Kiesselbach's Plexus?
Kiesselbach's plexus (also called Little's area) is a highly vascular region on the anteroinferior part of the nasal septum, about 1 cm from the nasal opening. It is the most common site of anterior epistaxis (90% of all nosebleeds).
Arterial Supply to Kiesselbach's Plexus
Five arteries anastomose here, coming from two major systems:
| Artery | Parent Vessel | System |
|---|---|---|
| Anterior ethmoidal artery | Ophthalmic artery → internal carotid | Internal carotid |
| Superior labial artery | Facial artery → external carotid | External carotid |
| Sphenopalatine artery | Maxillary artery → external carotid | External carotid |
| Greater palatine artery | Maxillary artery → external carotid | External carotid |
| Septal branch of superior labial | Facial artery | External carotid |
Why the Answer is B) Facial and Ophthalmic Arteries
The key point of this question is the anastomosis between the two major arterial systems:
Internal Carotid System External Carotid System
| |
Ophthalmic artery Facial artery
| |
Anterior ethmoidal Superior labial artery
| |
└──────── ANASTOMOSIS ────────────┘
↓
KIESSELBACH'S PLEXUS
- The ophthalmic artery (branch of internal carotid) contributes via the anterior ethmoidal artery
- The facial artery (branch of external carotid) contributes via the superior labial artery
- This is clinically the most important anastomosis because it connects the internal and external carotid systems on the nasal septum
Why Other Options Are Wrong
| Option | Why Wrong |
|---|---|
| A) Superior thyroid + facial | Superior thyroid artery supplies the thyroid gland - it has NO contribution to nasal septum |
| C) Sphenopalatine + greater palatine | Both are branches of the maxillary artery - same parent vessel, so this is NOT an anastomosis between two different systems |
| D) Superior thyroid + lingual | Neither supplies the nasal septum at all |
Clinical Importance
- Anterior epistaxis from Little's area is common, usually benign, and can be controlled by pinching the nose (compresses the anterior septal vessels)
- Posterior epistaxis (less common, more dangerous) involves the sphenopalatine artery deeper in the nose
- The dual blood supply (internal + external carotid) means that ligation of the external carotid alone may not stop bleeding - you must address both systems
Memory tip: "Facial and Ophthalmic = FOur fingers pinch the nose to stop the bleed" - these are the two main anastomosing systems at Kiesselbach's plexus.
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