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Surface Markings - Anatomy Practical (MBBS)

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1. Arch of Aorta

• Extent: Begins behind the right half of the sternal angle (manubriosternal junction, 2nd costal cartilage level) and ends to the left of the body of T4 vertebra.
• Surface projection: The convexity of the arch reaches up to the midpoint of the manubrium (roughly the level of the upper border of the 2nd right costal cartilage).
• Key landmark: The arch lies entirely within the superior mediastinum and is demarcated on the chest wall by an inverted "U" shape traced from the right 2nd costal cartilage, curving up to the suprasternal notch level, then down to the left 2nd costal cartilage.

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2. C7 Vertebra (Vertebra Prominens)

• Surface marking: The most prominent spinous process palpable at the base of the neck when the neck is flexed.
• Clinical note: C7 spinous process is NOT bifid (unlike C3-C6). It is the reference point for counting vertebral levels downward.
• Quick test: When the neck is bent forward, C7 is the most prominent bony point at the nape; T1 is immediately below it and slightly less prominent.

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3. Radial Nerve

• In the arm: Enters the posterior compartment by winding around the radial groove (spiral groove) of the humerus. A line drawn from the junction of the upper 1/3 and middle 1/3 of the posterior arm (where it enters the groove) to the lateral epicondyle represents its course in the spiral groove.
• In the forearm: From the lateral epicondyle, it divides into:
  • Superficial radial nerve: runs along the lateral border of the forearm under brachioradialis.
  • Deep branch (posterior interosseous nerve): winds around the neck of the radius to reach the posterior compartment.
• Key point: The nerve lies against bone in the spiral groove - hence it is injured in mid-shaft humeral fractures ("Saturday night palsy" / wrist drop).

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4. Frontal Eminence (Frontal Tuber)

• Location: The most prominent rounded elevation on each side of the frontal bone, approximately 3 cm above the midpoint of the supraorbital margin.
• Surface identification: Easily palpated as a smooth convex bulge on the forehead, one on each side of the midline (separated by the frontal suture/metopic suture line region).
• Significance: More prominent in children; site of reference in craniometric measurements.

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5. Anatomical Snuff Box

• Boundaries:
  • Medially (ulnar/posterior border): Tendon of extensor pollicis longus
  • Laterally (radial/anterior border): Tendons of extensor pollicis brevis and abductor pollicis longus
  • Floor: Styloid process of radius proximally, then scaphoid and trapezium
• Roof: Skin with the cephalic vein and superficial branch of radial nerve crossing it.
• Contents: Radial artery (crossing the floor deep)
• Clinical: Tenderness in the snuff box on pressure = suspect scaphoid fracture (even if X-ray is normal initially)

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6. Brachial Artery

• Course: Continuation of axillary artery from the lower border of teres major.
• Surface line: Draw a line from the medial epicondyle of the humerus to the midpoint of the anterior axillary fold (or from the junction of the anterior and middle thirds of the axilla). More precisely: a line joining the apex of the axilla to the midpoint between the bicipital tendon and the medial epicondyle in the cubital fossa.
• Practical method: The artery lies on the medial side of the arm along the medial bicipital groove (medial to the biceps tendon), accompanying the median nerve.
• Palpation: Felt in the cubital fossa, medial to the biceps tendon - the standard site for blood pressure measurement and brachial artery pulse.
• Bifurcation: Divides into radial and ulnar arteries at the level of the neck of the radius (about 2.5 cm below the medial epicondyle).

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7. Radial Artery

• Course: From the bifurcation of the brachial artery (neck of radius / cubital fossa) to the wrist.
• Surface line: A line from the midpoint of the cubital fossa (just medial to the biceps tendon) to the medial side of the styloid process of the radius.
• Pulse point: Felt between the tendons of flexor carpi radialis and brachioradialis at the wrist - the standard site for pulse examination.
• At the wrist: Lies on the distal radius lateral to the tendon of flexor carpi radialis.
• Beyond wrist: Passes through the anatomical snuff box, then between the two heads of first dorsal interosseous to enter the palm and form the deep palmar arch.

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8. Flexor Retinaculum

• Location: A fibrous band bridging the carpal bones on the anterior (palmar) aspect of the wrist, converting the carpal groove into the carpal tunnel.
• Surface marking:
  • Proximal border: A line along the distal wrist crease
  • Distal border: A line approximately 2.5 cm distal to the proximal border
• Attachments:
  • Medially: Pisiform and hook of hamate
  • Laterally: Scaphoid tubercle and ridge of trapezium
• Contents of carpal tunnel: 4 tendons of FDS, 4 tendons of FDP, tendon of FPL, and the median nerve (most superficial on the radial side)
• Clinical: Compression of the median nerve here = Carpal Tunnel Syndrome

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9. Extensor Retinaculum

• Location: A fibrous band on the posterior (dorsal) aspect of the wrist, holding extensor tendons in place.
• Surface marking: An oblique band running from the lateral margin of the radius (anterolaterally) to the pisiform and triquetrum (posteromedially), about 2 cm wide, crossing the posterior wrist.
• It has 6 compartments (from radial to ulnar):
  1. APL + EPB
  2. ECRL + ECRB
  3. EPL
  4. EDC + EI
  5. EDM
  6. ECU

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10. Glabella

• Location: The smooth, flattened triangular area on the frontal bone between the two superciliary arches (eyebrow ridges), just above the root of the nose (nasion).
• Surface identification: Palpable as the flat bony area between the eyebrows, above the bridge of the nose.
• Use: Reference point in craniometry; the glabellar tap reflex (Myerson's sign) is tested here - repeated tapping causes persistent blinking in Parkinson's disease.

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11. Median Nerve

• Arm: Runs with the brachial artery, initially lateral then crosses to the medial side of the artery at about the level of the mid-arm (insertion of coracobrachialis).
• Cubital fossa: Lies medial to the brachial artery, just behind the bicipital aponeurosis.
• Forearm: Passes between the two heads of pronator teres, then runs between FDS and FDP in the middle of the forearm.
• Wrist: Emerges at the medial side of the palmaris longus tendon (or between palmaris longus and flexor carpi radialis). Enters the carpal tunnel under the flexor retinaculum.
• Surface line: From the medial side of the cubital fossa to the midpoint of the wrist (between palmaris longus and FCR tendons). At the wrist, it lies superficially just above the retinaculum.

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12. Frankfurt Plane (Frankfort Horizontal Plane)

• Definition: A standard anatomical reference plane passing through the lower margin of the left orbit (infraorbital margin) and the upper margin of the external acoustic meatus (EAM) on both sides.
• Also called: Orbitomeatal plane or auriculo-orbital plane.
• Use: Standard position for the skull in anatomical and radiological descriptions; when the head is in the Frankfurt plane, it represents the natural horizontal head posture.
• Practical: Used in craniometry, forensic anthropology, and setting up lateral skull X-rays.

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13. Apex Beat

• Normal location: 5th left intercostal space, in the midclavicular line (approximately 9 cm from the midsternal line), just medial to the midclavicular line.
• In children: May be in the 4th ICS.
• Surface marking: Located at the intersection of the 5th left ICS and the left midclavicular line - felt as the outermost and lowermost point of definite cardiac pulsation.
• Abnormal shifts:
  • Shifted left + downward: Left ventricular enlargement (volume overload - AR, MR)
  • Shifted to the right: right-sided pleural effusion, left-sided collapse
  • Not felt: Obesity, emphysema, pericardial effusion

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14. Angle of Mandible

• Location: The junction of the posterior border (ramus) and the inferior border (body) of the mandible, at the posteroinferior corner of the mandible.
• Surface marking: Palpated just below and behind the ear at the gonion - where the jaw makes a right angle.
• Significance:
  • Site of masseter muscle attachment
  • Level of the facial artery as it winds around the lower border of the mandible (pulsation felt at anterior border of masseter)
  • Parotid gland overlies this region
  • Used for regional nerve blocks and airway assessment

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15. Sternal Angle (Angle of Louis / Manubriosternal Joint)

• Location: Junction of the manubrium and the body of the sternum - felt as a horizontal bony ridge/transverse ridge on the anterior chest wall.
• Level: Corresponds to the disc between T4 and T5 vertebrae.
• Key relationships at this level:
  • Articulation of the 2nd rib / 2nd costal cartilage (start counting ribs from here!)
  • Upper border of the pericardium
  • Bifurcation of the trachea (carina)
  • Beginning and end of the arch of the aorta
  • Azygos vein joins the SVC
  • Division between superior and inferior mediastinum

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16. Deep Palmar Arch

• Formation: Formed mainly by the terminal part of the radial artery + deep branch of the ulnar artery (smaller contribution).
• Level: Lies across the bases of the metacarpals, approximately 1 cm distal to the proximal transverse palmar crease (or about 1 fingerbreadth distal to the superficial arch).
• Surface marking: A curved line (convex distally) at the level of the proximal ends of the metacarpal bones (bases of metacarpals), under the thenar eminence.
• It lies deeper than the superficial arch - beneath the long flexor tendons.

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17. Superficial Palmar Arch

• Formation: Formed mainly by the ulnar artery + superficial branch of the radial artery (smaller contribution - or sometimes digital branch to thumb).
• Level: Lies across the palm at the level of the distal border of the extended thumb - a line drawn across the palm at the level of the thumb web space when the thumb is fully abducted, corresponding approximately to the proximal transverse palmar crease.
• Classic teaching: The arch lies at the level of Kaplan's cardinal line (a line drawn from the apex of the first web space to the hook of the hamate).
• More superficial than deep arch - lies just beneath the palmar aponeurosis.
• Mnemonic - Arch composition: "SUlnar, Uradial" - Superficial = Ulnar dominant; deep = Radial dominant.

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18. Zygomatic Arch

• Location: The bony bridge formed by the zygomatic process of the temporal bone and the temporal process of the zygomatic bone, stretching from the zygomatic bone anteriorly to the temporal bone posteriorly.
• Surface marking: A horizontal bony bar palpated from the posterior border of the zygomatic bone (below the lateral angle of the eye) to the anterior root of the zygoma in front of the tragus of the ear.
• It lies at the level of the Frankfurt plane.
• Significance:
  • Forms the superior limit of the infratemporal fossa
  • Gives origin to the masseter muscle (from its lower border)
  • Landmark for temporal fossa and auriculotemporal nerve blocks
  • Site of a common facial fracture ("tripod fracture")

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19. Ulnar Artery

• Course: From bifurcation of the brachial artery (at neck of radius) through the forearm to the wrist.
• Surface line: A line from a point 2.5 cm below the medial epicondyle to the lateral side of the pisiform bone at the wrist.
• Note: In the proximal forearm the ulnar artery is deep and cannot be easily palpated; in the distal forearm it becomes superficial between FCU and FDS, just lateral to the tendon of FCU.
• At the wrist: The ulnar artery and ulnar nerve pass superficial to the flexor retinaculum (through Guyon's canal = between pisiform and hook of hamate), NOT through the carpal tunnel.
• In the palm: Contributes the main trunk to the superficial palmar arch.

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Quick Summary Table

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• All 19 structures laid out in a 3-column card grid on a single A3 page
• Each card is colour-coded by region (Head, Thorax, Spine, Upper Limb subdivisions)
• Every card contains 4 rows:
  • Landmark - the key bony/surface reference point
  • Marking - exactly how to draw/palpate it
  • Relations - important neighbouring structures
  • Clinical - the exam-relevant clinical pearl
• Category legend at the top for quick colour orientation

• All 19 in one compact table with columns: Structure / Category / Landmark / How to Mark / Clinical Pearl
• Alternating row colours with category-coded number column
• Perfect for last-minute revision before practicals

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Surface Markings - Complete Anatomy Practical Guide (70 Items)

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HEAD & NECK

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1. Anatomical Snuff Box

• Boundaries: Medially - EPL tendon; Laterally - APL + EPB tendons; Floor - styloid process of radius → scaphoid → trapezium
• Roof: Cephalic vein + superficial radial nerve
• Contents: Radial artery (deep to floor)
• Clinical: Tenderness = scaphoid fracture; radial pulse palpable here

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2. Suprameatal Triangle (Macewen's Triangle)

• Location: Posterosuperior to the external acoustic meatus, on the lateral surface of the skull
• Boundaries:
  • Anterior: Posterosuperior wall of the EAM
  • Superior: Supramastoid crest (horizontal line from the upper border of EAM)
  • Posterior: Vertical tangent to the posterior wall of EAM
• Significance: This triangle overlies the mastoid antrum (tympanic antrum), which lies approximately 1.5 cm deep to this surface
• Clinical: Cortical mastoidectomy - the drill enters here to access the mastoid antrum; Macewen's triangle = safe entry zone for mastoid surgery

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5. C7 Vertebra (Vertebra Prominens)

• Surface marking: Most prominent spinous process palpable at the nape of the neck when the neck is flexed
• Not bifid (unlike C3-C6 spinous processes)
• Relations: First rib at same level; T1 immediately below (slightly less prominent)
• Clinical: Reference point for counting thoracic vertebrae downward; cervical rib arises from C7

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6. Paranasal Sinuses

• Frontal sinus is divided by a septum and is NOT symmetrical
• Clinical: Maxillary sinus floor is related to roots of upper premolar/molar teeth (sinusitis vs dental pain)

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9. Sternocleidomastoid (SCM)

• Origin: Sternal head - anterior surface of manubrium sterni; Clavicular head - medial 1/3 of clavicle
• Insertion: Mastoid process + superior nuchal line
• Surface marking: A prominent oblique strap muscle running from the sternoclavicular joint to the mastoid process - palpable when head is turned to the opposite side
• Divides the neck into: Anterior triangle (medial) and Posterior triangle (lateral)
• Relations: Carotid sheath structures lie deep to it; external jugular vein crosses it superficially
• Clinical: Torticollis (wry neck); SCM hematoma after birth trauma; guide for carotid artery pulsation

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10 & 67. Internal Jugular Vein (IJV)

• Course: From the jugular foramen (base of skull, posterior to carotid canal) to behind the sternoclavicular joint (where it joins the subclavian vein to form the brachiocephalic vein)
• Surface line: A line from the tragus of the ear (or the lobule of the ear) to the medial end of the clavicle (sternoclavicular joint)
• Relations: Runs within the carotid sheath with common carotid artery medially and vagus nerve posteriorly; overlapped by SCM
• Right IJV is preferred for central line insertion (more direct route to right atrium, no thoracic duct)
• Clinical: Central venous catheterization; JVP assessment; NOT pulsatile (unlike carotid)

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12. Facial Nerve (CN VII)

• Exits skull: Stylomastoid foramen (deep to mastoid process)
• Parotid gland course: Enters the posteromedial surface of the parotid, divides into 5 terminal branches within the gland
• Surface marking of main trunk: A point 1 cm below the tip of the mastoid process (or midway between the mastoid process and the angle of mandible)
• 5 terminal branches (mnemonic: "Two Zebras Bit My Cheek" / "To Zanzibar By Motor Car"):
  • Temporal - above zygomatic arch → frontalis, orbicularis oculi upper
  • Zygomatic - across zygomatic arch → orbicularis oculi lower
  • Buccal - parallel to parotid duct (at level of ala of nose)
  • Marginal mandibular - along lower border of mandible
  • Cervical - below angle of mandible → platysma
• Clinical: Parotid surgery risk; Bell's palsy; parotid malignancy invasion

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19. Glabella

• Location: Smooth triangular bony area on the frontal bone between the two superciliary arches, just above the root of the nose (nasion)
• Palpation: Flat bony prominence between the eyebrows above the bridge of the nose
• Clinical: Glabellar tap reflex (Myerson's sign) - tapping here causes persistent blinking in Parkinsonism (normal: blinking stops after a few taps)

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22. Parotid Gland

• Shape: Irregular wedge-shaped gland
• Surface marking:
  • Anterior border: Vertical line from the tragus of ear to the anterior border of masseter, reaching the lower border of mandible
  • Superior border: From the tragus to the zygomatic arch
  • Posterior border: From behind the EAM down to the mastoid process
  • Inferior border: 1 cm below the angle of mandible
• Parotid duct (Stensen's duct): A line from the tragus of the ear to the midpoint between the ala of nose and the upper lip (= midpoint of a line from ala to angle of mouth). Duct opens opposite the upper 2nd molar tooth.
• Relations: Facial nerve traverses it (extraglandularly); retromandibular vein, external carotid artery within gland
• Clinical: Parotitis, calculi, pleomorphic adenoma (most common benign tumor), facial nerve palsy after parotidectomy

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40. Facial Artery

• Origin: External carotid artery (in carotid triangle)
• Enters face: Winds around the lower border of the mandible at the anterior border of the masseter (pulsation felt here)
• Course on face: From the anteroinferior border of masseter → runs tortuously upward and medially toward the angle of the mouth → along the side of the nose (as angular artery) → terminates at the medial angle of the eye
• Surface line: From the lower border of mandible at the anterior masseter border → lateral side of nose → medial canthus of eye
• Pulse: Felt at the lower border of mandible, anterior to masseter - "facial pulse"
• Clinical: Ligation for facial hemorrhage; angiography; angular artery anastomoses with ophthalmic artery (ICA territory)

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43. Angle of Mandible

• Location: Gonion - the posteroinferior corner where the ramus meets the body of the mandible
• Palpation: Just below and anterior to the ear lobule
• Relations: Masseter inserts here; parotid gland overlies; facial artery curves around lower border of mandible at anterior masseter
• Clinical: Parotid swelling fills the angle; masseter hypertrophy; Mallampati/jaw assessment for intubation; mandibular nerve block landmark

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44. Frankfurt Plane

• Definition: Horizontal reference plane passing through the lower margin of the left orbit (infraorbital margin) and the upper margin of both external acoustic meatuses (EAM)
• Also known as: Orbitomeatal plane / auriculo-orbital plane
• Used for: Standard skull radiograph positioning, craniometry, forensic anthropology
• Practical significance: When the skull is in the Frankfurt plane, it represents the natural horizontal head posture when standing

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46. Zygomatic Arch

• Formed by: Temporal process of zygomatic bone (anteriorly) + zygomatic process of temporal bone (posteriorly)
• Surface marking: Horizontal bony bar palpated from below the lateral canthus of the eye to in front of the tragus of the ear
• Lies at the level of the Frankfurt plane
• Relations: Forms the roof of the infratemporal fossa; masseter arises from its lower border; temporalis passes deep to it
• Clinical: Tripod (malar/zygomatic) fracture; landmark for temporal fossa surgery; zygoma underlies "cheekbone" prominence

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48. Frontal Eminence (Frontal Tuber)

• Location: ~3 cm above the midpoint of the supraorbital margin on each side of the frontal bone
• Palpation: Smooth convex bulge on the forehead, one on each side of the midline
• More prominent in children
• Clinical: "Frontal bossing" in rickets, thalassemia major, hydrocephalus, Paget's disease

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50. Jugular Notch (Suprasternal Notch)

• Location: The U-shaped notch at the superior border of the manubrium sterni, between the two clavicles
• Surface: Easily palpable in the midline at the base of the neck
• Level: Corresponds to the lower border of T2 vertebra (or the disc between T2-T3)
• Relations: Trachea lies just behind it; brachiocephalic artery bifurcates just above this level on the right; left brachiocephalic vein crosses here

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58. Superciliary Arch

• Location: Ridge of bone on the frontal bone above each orbit, just above the medial eyebrow
• Palpation: Curved bony ridge above the orbit, more prominent in males
• Overlies: Frontal sinus (medially) and frontal lobe (laterally)
• Between the two superciliary arches lies the Glabella
• Clinical: Prominent superciliary arches (brow ridging) = acromegaly, Neanderthal-like habitus

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61. Carotid Pulse

• Common carotid artery pulse: Felt by pressing the fingertips gently against the side of the trachea at the level of the thyroid cartilage (C4-C5 level), between the trachea and the SCM
• Surface marking of common carotid: Line from the sternoclavicular joint to the level of the upper border of the thyroid cartilage (where it bifurcates into internal and external carotid at the level of C3-C4 disc / upper border of thyroid cartilage)
• Carotid sinus: Slight dilatation at the bifurcation, at the level of C3-C4
• Clinical: Carotid massage for SVT; carotid endarterectomy; carotid sinus hypersensitivity; arteriosclerosis causes diminished pulse

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63. Trachea

• Begins: Lower border of cricoid cartilage = C6 vertebra
• Ends (bifurcation/carina): T4-T5 intervertebral disc level (sternal angle / angle of Louis)
• Length: ~12 cm
• Surface marking: A midline structure from C6 downward; passes slightly to the right at its lower end
• Palpation: Felt as a firm tubular structure in the midline of the neck; tracheal ring cartilages palpable
• Clinical: Tracheal deviation (effusion/collapse); tracheal tug (aortic aneurysm); tracheostomy at 2nd-3rd ring

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64. Thyroid Gland

• Isthmus: Lies across tracheal rings 2, 3, and 4, at the level of C5-C6 vertebrae. Surface marked across the midline just below the cricoid cartilage.
• Lateral lobes: Extend from the lower border of the thyroid cartilage (C4) superiorly to the 5th or 6th tracheal ring inferiorly
• Surface marking: A "butterfly/H-shape" centered on the isthmus; each lobe is roughly 5 cm long x 3 cm wide
• Pyramidal lobe: When present, extends upward from the isthmus to the left of the midline toward the hyoid bone
• Relations: Isthmus anterior to 2nd-4th tracheal rings; lobes lateral to trachea and thyroid cartilage; recurrent laryngeal nerve lies in the tracheoesophageal groove
• Clinical: Goitre, thyroidectomy, recurrent laryngeal nerve injury

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65. Cavernous Sinus

• Location: On each side of the body of the sphenoid bone and the sella turcica, in the middle cranial fossa
• Extent: From the superior orbital fissure (anteriorly) to the apex of the petrous temporal bone (posteriorly)
• Surface projection: Deep to the temporal fossa and orbit - approximately corresponds to an area 1 cm lateral to the sella turcica, centered on the sphenoid body
• Contents (lateral wall, superior to inferior): CN III, CN IV, V1 (ophthalmic), V2 (maxillary); CN VI and internal carotid artery run within the sinus itself
• Clinical: Cavernous sinus thrombosis (danger triangle of face - veins drain here); pituitary tumour compression; carotid-cavernous fistula; painful ophthalmoplegia

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66. External Jugular Vein (EJV)

• Course: Formed by the confluence of the posterior auricular vein and the posterior division of the retromandibular vein, just below the ear
• Surface line: From the angle of the mandible (or just behind the earlobe) to the midpoint of the clavicle
• Runs obliquely across the SCM muscle (superficial to it), becoming more visible when the patient strains or the venous pressure is raised
• Drains into: Subclavian vein (passes through deep fascia just above the clavicle)
• Clinical: EJV reflects right atrial pressure (though less reliable than IJV); used for venous access; visible in raised JVP

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68. Submandibular Gland

• Location: Submandibular (digastric) triangle
• Surface marking: An almond-shaped gland filling the submandibular triangle, extending both above and below the mylohyoid muscle
• Boundaries of submandibular triangle: Anterior belly of digastric (anteriorly), posterior belly of digastric + stylohyoid (posteriorly), lower border of mandible (superiorly)
• Wharton's duct: Runs from the deep lobe forward to open at the sublingual papilla (beside the frenulum of tongue)
• Clinical: Submandibular calculi (commonest site for salivary calculi - Wharton's duct); submandibular swelling differential; Ludwig's angina

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70. Jugular Venous Arch

• Location: Connects the two anterior jugular veins just above the jugular notch (suprasternal notch), running transversely in the suprasternal space (of Burns)
• Surface marking: A transverse venous connection passing across the midline, approximately 2 cm above the jugular notch, within the suprasternal space
• Drains into: External jugular vein or directly into the subclavian vein on each side
• Clinical: At risk during low tracheostomy and midline neck incisions; can bleed profusely if cut

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THORAX

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4. Arch of Aorta

• Begins: Behind the right half of the sternal angle (manubriosternal junction) - level of T4 upper border / 2nd right costal cartilage
• Ends: Left side of T4 vertebral body (becomes descending thoracic aorta)
• Surface projection: Inverted U-shape - from the right 2nd costal cartilage, curving upward to the midpoint of the manubrium (reaching as high as the suprasternal notch), then downward to the left 2nd costal cartilage
• Convexity reaches: Level of the upper border of 1st right sternocostal joint (midmanubrium)
• Relations: Trachea bifurcation (carina) posteriorly at T4-T5; left recurrent laryngeal nerve hooks under it; left vagus crosses it; left phrenic nerve crosses it anteriorly
• Clinical: Aortic aneurysm causes tracheal tug, hoarseness (recurrent laryngeal palsy), dysphagia

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13. Sternal Angle (Angle of Louis / Manubriosternal Joint)

• Location: Junction of manubrium and body of sternum
• Palpation: A transverse bony ridge/step in the midline of the anterior chest
• Vertebral level: T4-T5 intervertebral disc
• Key relationships at T4-T5 level:
  • Articulation of 2nd costal cartilage (start counting ribs from here)
  • Upper border of the pericardium
  • Tracheal bifurcation (carina)
  • Beginning and end of the arch of the aorta
  • Azygos vein joins the SVC
  • Division between superior and inferior mediastinum
• JVP reference: Sternal angle lies ~5 cm above the midpoint of the right atrium (used as reference for JVP measurement)

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17. Inferior Vena Cava (IVC)

• Formation: Union of the two common iliac veins at the level of L5 vertebra (just to the right of the midline, at the level of the aortic bifurcation which is at L4)
• Course: Ascends on the right side of the aorta, on the posterior abdominal wall
• Passes through diaphragm: At the caval opening at the level of T8 vertebra (the most anterior, highest diaphragmatic opening - the "8 letters in caval opening" mnemonic)
• Enters right atrium: At the level of T8
• Surface marking: A line just to the right of the midline from L5 upward to T8
• Contents at different levels: At L5 = common iliac veins; at L3 = renal veins; at L2 = gonadal veins; at L1 = hepatic veins

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18. Superior Vena Cava (SVC)

• Formation: Union of the right and left brachiocephalic veins behind the lower border of the right 1st costal cartilage (level of T1 lower border)
• Course: Descends vertically downward on the right side of the mediastinum
• Enters right atrium: At the level of the 3rd right costal cartilage (or lower border of right 2nd costal cartilage)
• Surface marking: A line from the right sternoclavicular joint (or the junction of the 1st right rib with the sternum) running straight down 2-3 cm to the right of the sternal border to the level of the 3rd right costal cartilage / lower border of 2nd costal cartilage
• Azygos vein joins it at the level of the sternal angle (T4)
• Clinical: SVC syndrome (superior mediastinal compression - distended neck veins, facial oedema, arm oedema)

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35. Pleural Reflection

• Both sides: start at the sternoclavicular joints, converge toward the midline at the sternal angle (2nd costal cartilage)
• Right side: continues straight down close to the midline to the 6th right costal cartilage (xiphisternal junction)
• Left side: deviates laterally at the 4th costal cartilage to reach the apex of the cardiac notch at the 4th left costal cartilage, then turns down to the 6th left costal cartilage in the MCL
• Cardiac notch on the left side explains why the heart is accessible for pericardiocentesis without puncturing the pleura

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51. Pleura (Pleural Dome / Cervical Pleura)

• Dome of pleura (cervical pleura): Extends 2.5 cm above the medial end of the clavicle (1st rib level), or 1 cm above the junction of the medial and middle thirds of the clavicle
• Clinical: Apex of lung/pleural dome in the root of the neck = risk in subclavian line insertion, neck surgery, supraclavicular brachial plexus block (pneumothorax)

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52. Apex of Heart

• Location: The tip of the left ventricle
• Surface marking: 5th left intercostal space, at or just medial to the left midclavicular line, approximately 9 cm from the midsternal line
• In children: 4th left ICS

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53. Borders of Heart

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ABDOMEN

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3. Portal Vein

• Formation: Confluence of the superior mesenteric vein (SMV) and the splenic vein behind the neck of the pancreas, at the level of L1-L2 vertebra (approximately at the transpyloric plane)
• Surface marking: Approximately at the transpyloric plane (L1), slightly to the right of the midline, behind the neck of the pancreas
• Ascends in: Free edge of the lesser omentum (hepatoduodenal ligament)
• Tributaries: SMV + splenic vein (main); additionally receives left gastric, right gastric, cystic, and para-umbilical veins
• Clinical: Portal hypertension, portosystemic anastomoses (at gastroesophageal junction, umbilicus, rectum, retroperitoneum)

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8. Morris Parallelogram

• Definition: A surface marking for the kidney described by Morris, also called the "renal parallelogram"
• Construction:
  • Medial vertical line: 2.5 cm lateral to the midline (lateral to spinous processes)
  • Lateral vertical line: 9.5 cm lateral to the midline
  • Upper horizontal line: Level of the 11th thoracic vertebra (T11)
  • Lower horizontal line: Level of the 3rd lumbar vertebra (L3)
• The kidney lies within this parallelogram on each side of the back
• Clinical: Guides renal biopsy, nephrolithotomy positioning; helps locate renal angle (renal punch) tenderness

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11. Kidney

• Upper pole: 2.5 cm lateral to the spine at T12 on the posterior surface
• A line from the 12th thoracic vertebra to the 3rd lumbar vertebra, 2.5-9.5 cm lateral to the midline (posterior)

• Right kidney: between 11th rib and 3rd lumbar spinous process, 2.5-9.5 cm from midline
• Left kidney: slightly higher - between 10th/11th rib and 2nd-3rd lumbar spinous process

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21. Spleen

• Vertebral level: T9 to T11 (posterior surface against 9th, 10th, 11th ribs)
• Long axis: Lies along the 10th rib
• Surface marking:
  • Posterior end: at the T10 spinous process, 4-5 cm from the midline
  • Anterior end: just reaches the midaxillary line (does NOT normally cross the midaxillary line anteriorly - if it does, it is enlarged)
  • Superior border: 9th rib level
  • Inferior border: 11th rib level
• Dimensions: ~12 cm long, 7 cm wide, 3-4 cm thick (1-2-3 rule: 1 lb, 2×4×6 inches in BD Chaurasia)
• Notched superior border is a diagnostic feature of splenomegaly
• Clinical: Not normally palpable; palpable from RIF toward the LIF (patient turned right lateral); percussion dullness in left 9th ICS in MAL (Traube's space obliterated)

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23. Liver

• Upper border:
  • Right side: 5th rib in MCL (level of T8-T9)
  • Left side: 5th intercostal space just to the left of the midsternal line
• Lower border:
  • Right side: follows the costal margin from the 7th rib at the midaxillary line
  • Crosses the midline at the transpyloric plane (L1) - midway between xiphisternum and umbilicus
  • Left side: ends at the 5th left intercostal space in MCL / below the left costal margin
• Exact vertebral levels:
  • Right lobe upper extent: T8 posteriorly (just below right scapular angle)
  • Right lobe lower extent: L1-L2 (lower pole behind 10th-11th rib)
  • Left lobe: extends across to 5th left ICS
• Clinical: Hepatomegaly measured in cm below right costal margin in MCL; liver dullness on percussion; obliterated liver dullness = pneumoperitoneum

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25. Pancreas

• Key level: Transpyloric plane (L1) = neck of pancreas
• Head lies at L2, body at L1, tail reaches the splenic hilum
• Clinical: Pancreatic head carcinoma → obstructive jaundice (compresses CBD); pancreatitis (pain radiates to back at T12-L1)

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26. Iliac Crest

• Surface marking: The entire iliac crest is subcutaneous and easily palpable from the ASIS (anterior superior iliac spine) anteriorly to the PSIS (posterior superior iliac spine) posteriorly
• Vertebral level: The highest point of the iliac crest = L4 vertebra / L4-L5 intervertebral disc - used for lumbar puncture (insert needle at L3-L4 or L4-L5 space)
• Jacoby's (intercristal) line: Line joining the highest points of both iliac crests = L4 level
• Clinical: Bone marrow biopsy (PSIS), lumbar puncture reference, iliac crest bone graft harvest

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32. Quadrants of Abdomen

• Vertical plane: Median plane (through umbilicus, midline)
• Horizontal plane: Transumbilical plane (through the umbilicus, level of L3-L4 disc)

• 9-region division (by 2 vertical MCL planes + transpyloric and transtubercular): RH + Epigastric + LH (upper) / R Lumbar + Umbilical + L Lumbar (middle) / R Iliac + Hypogastric + L Iliac (lower)

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36. Root of Mesentery

• Attachment: From the left side of L2 vertebra (duodenojejunal flexure) diagonally downward to the right iliac fossa at the right sacroiliac joint (ileocaecal junction)
• Length of root: ~15 cm
• Crosses (from left-to-right, L2 to right SI joint):
  1. 3rd part of duodenum (at L3)
  2. Aorta and IVC
  3. Right ureter
  4. Right psoas muscle
  5. Right common iliac vessels
• Clinical: Root of mesentery is the axis around which volvulus of small intestine occurs

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37. Caecum

• Location: Right iliac fossa
• Vertebral level: Lies on the iliacus and psoas muscles in the right iliac fossa, at the level of the right inguinal ligament - approximately L5-S1 level
• Surface marking: An oval structure in the right iliac fossa, 6 cm wide and 7.5 cm long, centred roughly at the McBurney's point area, just above the lateral half of the right inguinal ligament
• Ileocaecal junction: At McBurney's point level
• Clinical: Caecal volvulus, carcinoma of caecum (most common right colonic tumour)

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39. McBurney's Point

• Location: On the right side, 1/3 of the way from the ASIS to the umbilicus (i.e., at the junction of the lateral 1/3 and medial 2/3 of a line drawn from the right ASIS to the umbilicus)
• Significance: Overlies the base of the appendix (the appendicular orifice / ileocaecal valve)
• Note: The position of the appendix tip varies (retrocaecal most common = 75%), but the base is constant at McBurney's point
• Lanz point: 1/3 from the right ASIS along a line between the two ASISes (slightly more medial - used for gridiron/McBurney's incision approach)
• Clinical: Maximum tenderness at McBurney's point in appendicitis; site of McBurney's (gridiron) incision

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42. Stomach

• Cardiac orifice (esophagogastric junction): T10-T11 vertebral level, 3-4 cm to the left of the midline (behind 7th left costal cartilage)
• Pyloric orifice: L1 vertebra (transpyloric plane), 1-2 cm to the right of the midline
• Fundus: Reaches the 5th left intercostal space (up to the level of the left dome of diaphragm)
• Body: From the cardiac notch to the incisura angularis
• Curvatures:
  • Greater curvature: Descends to the umbilicus level (L3-L4) when full
  • Lesser curvature: Faces right and upward

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45. Duodenum

• DJ flexure level: L2, to the left of midline, at the level of the transpyloric plane
• Duodenojejunal flexure is held by the ligament of Treitz (suspensory muscle of duodenum)

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54. Intestine

• Jejunum: Upper 2/5 of small intestine; mainly in the umbilical and left lumbar regions (upper left abdomen)
• Ileum: Lower 3/5; mainly in the umbilical, hypogastric, right iliac, and pelvic regions
• Total length: ~6 m (jejunum ~2.4 m, ileum ~3.6 m)

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59. Appendicular Orifice

• Same as McBurney's point - the base of the appendix (and the ileocaecal valve / appendicular orifice) is located at McBurney's point: 1/3 of the way from the ASIS to the umbilicus on the right side
• Exact anatomical position: On the posteromedial wall of the caecum, 2-3 cm below the ileocaecal junction
• Three taeniae coli of the caecum converge at the base of the appendix (surgical guide)

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62. Transpyloric Plane (of Addison)

• Level: L1 vertebra - midway between the jugular notch (suprasternal notch) and the pubic symphysis; also midway between the xiphisternum and the umbilicus
• Palpation: Felt as the level where tensing the rectus abdominis (asking patient to lift head) creates a skin crease at L1 level
• Structures at the transpyloric plane (L1):
  • Pylorus of stomach
  • Fundus of gallbladder (tip of 9th costal cartilage)
  • Neck of pancreas
  • Formation of portal vein
  • First lumbar vertebra (L1)
  • Superior mesenteric artery origin from aorta
  • Hilum of kidneys (left kidney slightly higher)
  • DJ flexure (just below and to the left)
  • Coeliac trunk (just above, at T12/L1)
  • Spinal cord ends (L1-L2 = conus medullaris)
• Mnemonic: "9 × 9 = L1" (9th costal cartilage × 9 structures)

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69. Transtubercular Plane

• Level: L5 vertebra - a horizontal plane passing through the iliac tubercles (the most prominent posterior point of the iliac crest, ~5 cm posterior to the ASIS)
• Structures at L5:
  • Aortic bifurcation (into common iliac arteries) - actually at L4, just above this plane
  • IVC formation - at L5 (just below aortic bifurcation)
  • Beginning of common iliac arteries
• Note: Together with the transpyloric plane (L1) and the subcostal plane (L3), the transtubercular plane forms the standard reference planes for abdominal surface anatomy

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UPPER LIMB

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7 & 30. Brachial Artery

• Course: Continuation of axillary artery from the lower border of teres major
• Surface line: A line from the apex of the axilla (medial to the coracobrachialis tendon) along the medial bicipital groove to the midpoint of the cubital fossa (midpoint between epicondyles, just medial to the biceps tendon)
• Accompaniment: Median nerve runs with it - initially lateral, crosses anterior surface at mid-arm to lie medial in the cubital fossa
• Bifurcation: Into radial + ulnar arteries at the level of the neck of the radius (~2.5 cm below the medial epicondyle)
• BP measurement: Arm at the level of the heart; stethoscope placed over brachial artery in cubital fossa, medial to biceps tendon
• Clinical: Supracondylar fracture → anterior interosseous nerve injury; Volkmann's ischaemic contracture

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14. Median Nerve

• Arm: Lateral to brachial artery proximally; crosses anterior to brachial artery at mid-arm to lie medially in the cubital fossa
• Surface line: From the medial side of the cubital fossa (medial to brachial artery) to the midpoint of the wrist between the palmaris longus tendon and flexor carpi radialis tendon
• Forearm: Between the 2 heads of pronator teres → runs between FDS and FDP in the middle of the forearm
• Wrist: Emerges lateral to the palmaris longus tendon (or medial to FCR); enters carpal tunnel beneath flexor retinaculum
• Clinical: Carpal tunnel syndrome (ape hand, LOAF muscles); pronator teres syndrome; AIN palsy (anterior interosseous nerve)

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16. Flexor Retinaculum (Hand)

• Location: Anterior (palmar) wrist, bridging the carpal groove to form the carpal tunnel
• Surface marking:
  • Proximal border: Distal wrist crease
  • Distal border: ~2.5 cm distal to the proximal border
• Attachments: Pisiform and hook of hamate (medially); scaphoid tubercle and ridge of trapezium (laterally)
• Contents of carpal tunnel (deep to retinaculum): 4 FDS + 4 FDP + FPL tendons + median nerve (superficial, radial side)
• Note: Ulnar nerve and ulnar artery pass superficial to the flexor retinaculum (through Guyon's canal)
• Clinical: Carpal tunnel syndrome; Phalen's test; Tinel's sign at wrist

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20. Superior Extensor Retinaculum (Foot)

• Location: Anterior ankle, above the inferior extensor retinaculum
• Surface marking: A transverse band ~2 cm wide, crossing the anterior aspect of the distal leg just above the ankle joint, from the lower anterior fibula to the lower anterior tibia
• Contents (deep to it): Tibialis anterior, EHL, EDL, EDB (peroneus tertius), anterior tibial vessels, deep peroneal nerve
• Note: The inferior extensor retinaculum (Y-shaped) is just below it, crossing the ankle to the calcaneus and medial cuneiform
• Clinical: Anterior compartment syndrome; extensor tendon injuries

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24. Axillary Artery

• Definition: Continuation of the subclavian artery, from the outer border of the 1st rib to the lower border of the teres major
• Surface marking: Line from the midpoint of the clavicle to the anterior axillary fold (lower border of pectoralis major), or: from the midpoint of the clavicle to the medial epicondyle (the entire upper limb arterial axis line)
• Three parts (divided by pectoralis minor):
  • Part 1 (medial to pec minor): 1 branch (superior thoracic)
  • Part 2 (behind pec minor): 2 branches (thoracoacromial + lateral thoracic)
  • Part 3 (lateral to pec minor): 3 branches (subscapular + anterior + posterior circumflex humeral)
• Clinical: Axillary artery aneurysm; brachial plexus blocks (infraclavicular, axillary); shoulder dislocation can injure axillary nerve (not axillary artery usually)

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28. Superficial Palmar Arch

• Formation: Mainly ulnar artery + superficial branch of radial artery (or sometimes the princeps pollicis)
• Level: At the level of the distal border of the fully abducted/extended thumb - corresponds to the proximal transverse palmar crease
• Surface line: A curved line (convex distally) from the medial side of the palm at the pisiform level, curving to the thenar eminence - at the level of Kaplan's cardinal line
• Lies: Deep to the palmar aponeurosis, superficial to the long flexor tendons
• Branches: 3 common palmar digital arteries + 1 proper palmar digital to the ulnar side of the little finger

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29. Deep Palmar Arch

• Formation: Mainly radial artery (after passing through the first dorsal interosseous space) + deep branch of ulnar artery
• Level: Across the bases (proximal ends) of the metacarpal bones - ~1 cm proximal to the superficial arch
• Surface line: A curved line at the bases of the metacarpals, deep to the long flexor tendons
• Mnemonic: "SUlnar / Uradial" - Superficial = Ulnar dominant; Deep = Radial dominant

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34. Ulnar Nerve

• Arm: Medial to brachial artery, passes through the medial intermuscular septum at the mid-arm
• Posterior to medial epicondyle: Passes in the cubital tunnel / sulcus ulnaris (palpable here - "funny bone" area)
• Surface line: A line from behind the medial epicondyle (palpable) to the lateral side of the pisiform at the wrist
• Wrist: Passes through Guyon's canal (lateral to the pisiform, superficial to flexor retinaculum), with the ulnar artery lateral to it
• Clinical: Cubital tunnel syndrome (ulnar neuropathy at elbow); claw hand (ring + little fingers); ulnar paradox; Guyon's canal compression

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LOWER LIMB

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27. Patella

• Location: Largest sesamoid bone; lies within the quadriceps tendon, anterior to the knee joint
• Surface marking: A flattened ovoid bone palpable on the anterior knee, with:
  • Base (upper border): at the level of the knee joint line minus 2 cm - approximately at the junction of the middle and lower thirds of the femur
  • Apex (lower border): ~6 cm below the base; connected to the tibial tuberosity by the patellar ligament
• Vertebral level: The patella sits anterior to the knee joint; the knee joint line itself is at the level of L3-L4 dermatome
• Clinical: Patella fracture; patellar tap sign (effusion); patellofemoral syndrome; bipartite patella

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33. Radius

• Head of radius: Palpable in a hollow just distal to the lateral epicondyle of the humerus; felt rotating when forearm pronates/supinates
• Shaft surface marking: Lateral aspect of the forearm from the lateral epicondyle distally
• Styloid process: The prominent bony point on the lateral wrist - extends 1 cm more distally than the ulnar styloid (important for clinical examination)
• Radial surface (distal): Broad, triangular articular surface for the wrist joint (radiocarpal joint)
• Clinical: Colles' fracture (distal radius + dinner fork deformity); Smith's fracture; radial styloid = anatomical snuff box floor; lower end of radius most commonly fractured bone in body

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38. Greater Trochanter

• Location: The large bony prominence on the lateral side of the proximal femur, at the junction of the femoral neck and shaft
• Surface marking: Palpable on the lateral thigh, approximately a hand's breadth below the iliac crest at the level of the pubic symphysis (both are at the same horizontal level)
• Vertebral level: Level of the pubic symphysis - both are at the same horizontal plane (useful clinical landmark)
• Relations: Gluteus medius and minimus insert here; piriformis inserts at the medial surface of the greater trochanter; sciatic nerve lies just posterior to it
• Clinical: Trochanteric bursitis; gluteus medius lurch (Trendelenburg gait in hip abductor weakness); greater trochanter fracture; used for surgical approaches to the hip (lateral approach)

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41. Saphenous Opening (Fossa Ovalis)

• Location: An oval aperture in the fascia lata (deep fascia of thigh), ~3.8 cm (1.5 inches) below and lateral to the pubic tubercle
• Surface marking: ~4 cm below and 4 cm lateral to the pubic tubercle, in the anterior upper thigh
• Contents: The great saphenous vein passes through this opening to drain into the femoral vein; also transmits the superficial epigastric, superficial circumflex iliac, and superficial external pudendal vessels
• Covered by: Cribriform fascia (the cribriform plate - a perforated fascia)
• Clinical: Femoral hernia emerges through the femoral ring and may present as a lump at/below the saphenous opening; sapheno-femoral junction ligation at this point

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47. Medial Malleolus

• Location: Bony prominence on the medial side of the ankle, the lower end of the tibia
• Surface marking: Easily palpable on the medial ankle; its lower tip is ~1.5 cm above the sole
• Level: The medial malleolus is approximately 2.5 cm higher than the lateral malleolus
• Relations: Posterior tibial artery, tibial nerve, and tendons (tibialis posterior, FDL, FHL) pass behind it in the tarsal tunnel (under the flexor retinaculum of the foot)
• Clinical: Medial malleolus fracture (bimalleolar/trimalleolar fracture); tarsal tunnel syndrome (medial malleolus to calcaneus); ankle sprain (usually lateral)

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49. Tibial Tuberosity

• Location: Anterior surface of the upper tibia, below the knee joint
• Surface marking: A smooth bony prominence palpable ~5 cm below the apex of the patella, in the midline of the anterior shin
• Level: Just below the knee joint
• Insertion: Patellar ligament (ligamentum patellae) inserts here
• Clinical: Osgood-Schlatter disease (tibial tuberosity apophysitis in adolescents); patellar ligament avulsion; landmark for tibial intramedullary nail insertion; tibial plateau fracture just above this

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55. Femoral Triangle

• Boundaries:
  • Base (superior): Inguinal ligament
  • Medial border: Medial border of adductor longus
  • Lateral border: Medial border of sartorius
  • Apex: Where medial border of sartorius meets adductor longus (~10 cm below inguinal ligament)
  • Roof: Fascia lata + skin
  • Floor: Iliopsoas (lateral) + pectineus (medial) + adductor longus (medially)
• Contents (lateral → medial: NAVL):
  • Nerve (femoral nerve - lateral, outside femoral sheath)
  • Artery (femoral artery - within femoral sheath)
  • Vein (femoral vein - within femoral sheath, medial to artery)
  • Lymphatics + empty space (femoral canal - most medial compartment of femoral sheath)
• Clinical: Femoral hernia (through femoral ring into femoral canal); femoral artery puncture for angiography; femoral nerve block; femoral lymphadenopathy; inguinal lymph node dissection

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56. Mid-Inguinal Point

• Location: Midpoint of the inguinal ligament - midpoint between the ASIS and the pubic symphysis
• Overlies: The femoral artery as it passes under the inguinal ligament (femoral pulse felt here)
• Distinguished from: The midpoint of the inguinal ligament (same), vs. the deep inguinal ring (which is at the midpoint of the inguinal ligament, also ~1.5 cm above this point - "mid-point of inguinal ligament" is a synonym)
• Note: The deep inguinal ring lies 1-1.5 cm above and lateral to the pubic tubercle, at the mid-inguinal point
• Clinical: Femoral pulse palpation; femoral artery cannulation; femoral hernia vs inguinal hernia (inguinal = above and medial to pubic tubercle; femoral = below and lateral)

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57. Flexor Retinaculum (Foot) / Laciniate Ligament

• Location: Medial ankle and foot
• Surface marking: From the medial malleolus to the medial surface of the calcaneus, passing across the medial ankle
• Contents (from anterior to posterior through the tarsal tunnel = THICKLY mnemonic):
  • Tibialis posterior
  • Hallucis longus flexor (FHL) - most posterior
  • Intermediate = between them is FDL
  • Calcaneal branch of posterior tibial nerve
  • tibial artery (posterior) and veins
  • tibial Nerve - most superficial
  • Actually: Tibialis posterior / FDL / posterior tibial vessels + tibial nerve / FHL (Tom, Dick, And Very Nervous Harry)
• Clinical: Tarsal tunnel syndrome (tibial nerve compression) = burning pain + paraesthesia over sole; plantar fasciitis related area

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MISCELLANEOUS / SPECIAL PLANES

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15. Anterior Fontanelle

• Location: At the junction of the coronal, sagittal, and metopic (frontal) sutures = bregma
• Shape: Diamond/rhomboid-shaped, ~4 cm × 2.5 cm at birth
• Closure: Closes between 9-18 months (most commonly ~12-18 months after birth)
• Surface marking: Palpated as a soft, pulsatile, slightly depressed or flat area at the top of the skull in infants, at the intersection of the midline and a coronal line through the ears
• Clinical:
  • Bulging = raised ICP (meningitis, hydrocephalus, subdural hematoma)
  • Depressed = dehydration
  • Delayed closure = hypothyroidism, rickets, Down syndrome, hydrocephalus
  • Used for cranial ultrasound in neonates (acoustic window)

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60. Cubital Fossa

• Boundaries:
  • Lateral border: Brachioradialis
  • Medial border: Pronator teres
  • Base (superior): Imaginary line joining the two epicondyles
  • Floor: Supinator (laterally) + brachialis (medially)
  • Roof: Bicipital aponeurosis + deep fascia + skin
• Contents (lateral → medial: TAN or BENT):
  • Tendon of biceps
  • Artery (brachial artery - bifurcates here into radial + ulnar)
  • Nerve (median nerve - medial to brachial artery)
  • The radial nerve is in the groove between brachioradialis and brachialis (not strictly in the fossa contents)
• Clinical: BP measurement; venipuncture (median cubital vein visible in roof); brachial artery catheterization; cubital tunnel vs. median nerve compression here

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53 (additional). Borders of Heart - Summary

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QUICK VERTEBRAL LEVEL SUMMARY TABLE

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• Structure name + number (colour-coded by region)
• Vertebral level (highlighted in gold for all organ structures)
• Landmark - the bony/surface reference
• Marking - exactly how to draw/identify it
• Relations - key neighbouring structures
• Clinical - exam-relevant pearl (in red)

• Purple = Head & Neck
• Dark blue = Thorax
• Green = Abdomen
• Red = Upper Limb
• Orange = Lower Limb
• Teal = Reference Planes