MBBS First Professional (CBME) – Anatomy Paper I (August 2025)

Model Answers

I. Essay (10 Marks)

Question 1

A 62-year-old bus conductor came to the surgery OPD with complaints of pain in his right leg for the past 6 months. Clinical examination revealed dilated, tortuous veins in the medial aspect of the right lower limb and was diagnosed to have varicose veins.

a) Describe the formation, course and relations, tributaries and termination of the great saphenous vein. (1+2+3+1 Marks)

Answer

Formation

  • Formed by the union of the medial marginal vein with the medial end of the dorsal venous arch of the foot.
  • Begins in front of the medial malleolus.

Course

  • Passes anterior to the medial malleolus.
  • Ascends along the medial side of the leg.
  • Passes behind the medial condyle of the femur.
  • Ascends along the medial side of the thigh.
  • Pierces the cribriform fascia at the saphenous opening.
  • Terminates in the femoral vein.

Relations

In the Leg

  • Lies in superficial fascia.
  • Accompanied by the saphenous nerve.

At the Knee

  • Passes behind the medial condyle.

In the Thigh

  • Lies superficial to fascia lata.
  • Pierces the cribriform fascia before entering the femoral vein.

Tributaries

  • Superficial epigastric vein
  • Superficial circumflex iliac vein
  • Superficial external pudendal vein
  • Posterior arch vein
  • Numerous cutaneous veins

Termination

  • Opens into the femoral vein through the saphenous opening.

b) Explain the anatomical basis of varicose veins. (3 Marks)

Answer

Varicose veins are permanently dilated, elongated and tortuous superficial veins.

Anatomical Basis

  • Failure of venous valves.
  • Weakening of vein wall.
  • Increased venous pressure.
  • Blood refluxes from deep veins into superficial veins through incompetent perforators.
  • Great saphenous vein is commonly affected.

Predisposing Factors

  • Prolonged standing
  • Pregnancy
  • Obesity
  • Old age

Clinical Features

  • Dilated tortuous veins
  • Pain and heaviness
  • Edema
  • Venous ulcers near medial malleolus

II. Reasoning Out Short Notes (5 Marks Each)

Question 2

Intramuscular injection in the arm may lead to inability to abduct the arm. Give reasons for the above statement.

Answer

  • Intramuscular injection given incorrectly in the deltoid region may injure the axillary nerve.
  • The axillary nerve winds around the surgical neck of the humerus through the quadrangular space.
  • It supplies:
    • Deltoid
    • Teres minor
  • Deltoid is responsible for abduction of the arm from 15° to 90°.
  • Injury causes:
    • Loss of abduction
    • Flattening of shoulder
    • Wasting of deltoid
    • Loss of sensation over the regimental badge area.

Question 3

Haematemesis occurs in portal hypertension – Reason out.

Answer

Portal hypertension increases pressure in the portal venous system.

Portosystemic Anastomosis

Occurs at:

  • Lower end of oesophagus
  • Umbilicus
  • Anal canal

At the lower end of oesophagus:

  • Portal vein → Left gastric vein
  • Systemic vein → Oesophageal veins → Azygos vein

Raised portal pressure produces:

  • Oesophageal varices
  • Rupture of varices
  • Massive haematemesis

III. Short Notes (6 Marks Each)

Question 4

Write a short note on Anatomical Snuff Box and its applied aspects.

Answer

Boundaries

Lateral

  • Abductor pollicis longus
  • Extensor pollicis brevis

Medial

  • Extensor pollicis longus

Floor

  • Scaphoid
  • Trapezium

Roof

  • Skin
  • Superficial fascia

Contents

  • Radial artery
  • Cephalic vein
  • Superficial branch of radial nerve

Applied Anatomy

  • Scaphoid fracture
  • Radial artery palpation
  • Tenderness in anatomical snuff box

Question 5

Write a short note on Cadaver as the First Teacher.

Answer

  • Provides three-dimensional understanding of anatomy.
  • Helps correlate anatomy with clinical practice.
  • Develops surgical skills.
  • Improves manual dexterity.
  • Teaches professionalism and ethics.
  • Encourages respect for the human body.
  • Forms the foundation of medical education.

Question 6

Write a short note on Midgut Rotation.

Answer

Midgut rotates around the superior mesenteric artery.

Stages

  • Physiological herniation.
  • 90° anticlockwise rotation.
  • Return to abdominal cavity.
  • Additional 180° anticlockwise rotation.

Total rotation = 270° anticlockwise.

Applied Anatomy

  • Malrotation
  • Volvulus
  • Internal hernia

Question 7

Write a short note on Histological differences between lymph node and spleen.

Answer

Lymph NodeSpleen
Filters lymphFilters blood
Cortex and medullaWhite pulp and red pulp
Afferent lymphatics presentNo afferent lymphatics
Medullary cords presentSplenic cords present
Hilum presentHilum present

Question 8

Write a short note on Synovial Joint.

Answer

Features

  • Articular cartilage
  • Synovial membrane
  • Joint cavity
  • Synovial fluid
  • Fibrous capsule
  • Ligaments

Types

  • Plane
  • Hinge
  • Pivot
  • Condyloid
  • Saddle
  • Ball-and-socket

Functions

  • Free movement
  • Shock absorption
  • Stability

Question 9

Write a short note on Superficial Perineal Pouch.

Answer

Boundaries

  • Roof – Perineal membrane
  • Floor – Colles’ fascia

Contents in Male

  • Root of penis
  • Bulb of penis
  • Crura
  • Bulbospongiosus muscle
  • Ischiocavernosus muscle
  • Superficial transverse perineal muscle
  • Pudendal vessels and nerves

Contents in Female

  • Clitoris
  • Vestibular bulbs
  • Greater vestibular glands
  • Associated muscles

Question 10

Write a short note on the Anatomical basis of Carpal Tunnel Syndrome.

Answer

Cause

Compression of the median nerve beneath the flexor retinaculum.

Causes

  • Rheumatoid arthritis
  • Pregnancy
  • Diabetes mellitus
  • Repetitive wrist movements

Clinical Features

  • Pain
  • Tingling
  • Numbness
  • Thenar muscle wasting
  • Ape thumb deformity

Question 11

Write a short note on Lymphatic drainage of the stomach and its applied aspects.

Answer

Lymphatic Drainage

  • Left gastric lymph nodes
  • Right gastric lymph nodes
  • Left gastroepiploic lymph nodes
  • Right gastroepiploic lymph nodes
  • Pancreaticosplenic lymph nodes
  • Pyloric lymph nodes

All ultimately drain into the coeliac lymph nodes.

Applied Anatomy

  • Spread of gastric carcinoma through lymphatics.
  • Enlargement of Virchow’s (left supraclavicular) node may occur in advanced gastric cancer.

Question 12

Write a short note on Longitudinal arch of foot and factors maintaining it.

Answer

Types

  • Medial longitudinal arch
  • Lateral longitudinal arch

Factors Maintaining the Arch

Passive Factors

  • Shape of bones
  • Plantar aponeurosis
  • Spring ligament
  • Long plantar ligament

Active Factors

  • Tibialis anterior
  • Tibialis posterior
  • Flexor hallucis longus
  • Flexor digitorum longus

Applied Anatomy

  • Flat foot (Pes planus)

Question 13

Write a short note on Prostate gland and its applied aspects.

Answer

Situation

  • Lies below the urinary bladder.
  • Surrounds the prostatic urethra.

Lobes

  • Anterior lobe
  • Median lobe
  • Posterior lobe
  • Two lateral lobes

Blood Supply

  • Inferior vesical artery
  • Middle rectal artery

Venous Drainage

  • Prostatic venous plexus

Applied Anatomy

  • Benign prostatic hyperplasia (BPH)
  • Carcinoma of the prostate
  • Urinary retention
  • Digital rectal examination (DRE)
  • Transurethral resection of the prostate (TURP)

MBBS First Professional (CBME) – Anatomy Paper II (August 2025)

Essay & Short Notes – Model Answers

Based on the uploaded question paper.

I. Essay (10 Marks)

Question 1

A 67-year-old male, known case of uncontrolled hypertension and diabetes, was brought to the hospital with complaints of sudden onset of slurred speech and inability to move the right side of the body and limbs. Clinical examination revealed increased muscle tone and tendon reflexes and positive Babinski sign on the affected side. MRI showed a vascular lesion on white matter of the left cerebral hemisphere. He was diagnosed with internal capsule lesion.

a) Describe the parts and relations of the internal capsule, arrangement of fibres and arterial supply of the internal capsule. (2+3+3 Marks)

Answer

Definition

The internal capsule is a compact band of projection fibers situated between the basal ganglia and thalamus, carrying ascending and descending nerve fibers between the cerebral cortex and lower centers.

Parts

  1. Anterior limb
  2. Genu
  3. Posterior limb
  4. Retrolentiform part
  5. Sublentiform part

Relations

Anterior limb

  • Medial – Head of caudate nucleus
  • Lateral – Lentiform nucleus

Genu

  • Junction of anterior and posterior limbs.

Posterior limb

  • Medial – Thalamus
  • Lateral – Lentiform nucleus

Retrolentiform part

  • Posterior to lentiform nucleus

Sublentiform part

  • Inferior to lentiform nucleus

Arrangement of Fibres

Anterior limb

  • Frontopontine fibres
  • Anterior thalamic radiations

Genu

  • Corticonuclear (corticobulbar) fibres

Posterior limb

  • Corticospinal fibres
  • Sensory fibres (thalamocortical)
  • Corticorubral fibres

Retrolentiform part

  • Optic radiation
  • Parietopontine fibres

Sublentiform part

  • Auditory radiation
  • Temporopontine fibres

Arterial Supply

  • Anterior limb: Medial striate artery (recurrent artery of Heubner) and lateral striate arteries
  • Genu: Lateral striate arteries
  • Posterior limb: Lateral striate arteries and anterior choroidal artery
  • Retrolentiform part: Posterior cerebral artery
  • Sublentiform part: Anterior choroidal artery and posterior cerebral artery

b) Explain the anatomical basis of the clinical features in this condition. (2 Marks)

Answer

The posterior limb of the internal capsule contains corticospinal fibres controlling voluntary movements of the opposite side of the body.

A vascular lesion involving the left internal capsule damages these descending motor fibres, resulting in:

  • Contralateral (right-sided) hemiplegia
  • Upper motor neuron signs
    • Increased muscle tone (spasticity)
    • Hyperactive tendon reflexes
    • Positive Babinski sign
  • Slurred speech (dysarthria) due to involvement of corticobulbar fibres in the genu.

Hypertension commonly causes rupture of lenticulostriate arteries, producing capsular stroke.

II. Reasoning Out Short Notes (5 Marks Each)

Question 2

Genioglossus is the safety muscle of tongue – Reason out.

Answer

The genioglossus is the chief protrusor muscle of the tongue.

  • It arises from the superior mental spine of the mandible.
  • It is supplied by the hypoglossal nerve (CN XII).
  • On contraction, it protrudes and depresses the tongue.

Reason

  • During unconsciousness or general anaesthesia, paralysis of the genioglossus allows the tongue to fall backwards.
  • The tongue may obstruct the airway and cause respiratory difficulty.
  • Contraction of the genioglossus pulls the tongue forward, keeping the airway open.

Hence, the genioglossus is called the “safety muscle of the tongue.”

Question 3

Black eye occurs in injury to scalp – Reason out.

Answer

A black eye (periorbital ecchymosis) is caused by accumulation of blood in the eyelids following scalp injury.

Anatomical Basis

  • Blood from the scalp collects in the loose areolar tissue (dangerous area) of the scalp.
  • It cannot spread posteriorly because the occipitalis muscle is attached to bone.
  • Anteriorly, the frontalis muscle has no bony attachment.
  • Therefore, blood tracks into the eyelids through the loose connective tissue.
  • The eyelids become swollen and discolored, producing a black eye.

III. Short Notes (6 Marks Each)

Question 4

Write a short note on Pharyngeal Arches.

Answer

  • Pharyngeal arches are mesodermal structures that appear during the 4th week of embryonic development.
  • Each arch contains:
    • Cartilage
    • Muscle
    • Cranial nerve
    • Artery (aortic arch)

Derivatives

  • First arch: Muscles of mastication, maxilla, mandible; CN V.
  • Second arch: Muscles of facial expression; CN VII.
  • Third arch: Stylopharyngeus; CN IX.
  • Fourth & Sixth arches: Muscles of pharynx and larynx; CN X.

Applied Anatomy

  • Branchial cyst
  • Branchial fistula
  • Congenital anomalies

Question 5

Write a short note on Principles of Communication.

Answer

Principles of effective communication include:

  • Active listening
  • Empathy
  • Respect
  • Confidentiality
  • Clear and simple language
  • Appropriate verbal and non-verbal communication
  • Feedback
  • Patient-centred approach
  • Professional behaviour

Importance

  • Builds doctor–patient relationship
  • Improves compliance
  • Reduces misunderstandings

Question 6

Write a short note on Interior of Larynx.

Answer

The interior of the larynx extends from the laryngeal inlet to the lower border of the cricoid cartilage.

Divisions

  • Vestibule
  • Ventricle
  • Infraglottic cavity

Important Features

  • Vestibular folds (false vocal cords)
  • Vocal folds (true vocal cords)
  • Rima glottidis
  • Laryngeal ventricle

Applied Anatomy

  • Laryngoscopy
  • Vocal cord paralysis
  • Laryngeal carcinoma

Question 7

Write a short note on Histology of Tongue.

Answer

  • Covered by stratified squamous epithelium.
  • Skeletal muscle fibres arranged in three planes.
  • Papillae:
    • Filiform
    • Fungiform
    • Circumvallate
    • Foliate
  • Taste buds present on fungiform, foliate, and circumvallate papillae.
  • Lingual glands present in submucosa.

Question 8

Write a short note on Phrenic Nerve.

Answer

Origin

  • Ventral rami of C3, C4, C5 (“C3, 4, 5 keep the diaphragm alive”).

Course

  • Descends on the anterior surface of scalenus anterior.
  • Enters the thorax.
  • Passes anterior to the root of the lung.
  • Ends in the diaphragm.

Supply

  • Motor: Diaphragm
  • Sensory: Fibrous pericardium, mediastinal pleura, diaphragmatic pleura, central diaphragmatic peritoneum.

Applied Anatomy

  • Phrenic nerve palsy causes diaphragmatic paralysis.
  • Referred pain to the shoulder (C4 dermatome).

Question 9

Describe the cut section of the medulla at the pyramidal level.

Answer

Structures seen include:

  • Pyramids
  • Corticospinal tracts
  • Inferior olivary nucleus
  • Medial lemniscus
  • Hypoglossal nucleus
  • Dorsal motor nucleus of vagus
  • Medial longitudinal fasciculus
  • Reticular formation
  • Fourth ventricle

Applied Anatomy

  • Medial medullary syndrome
  • Lateral medullary (Wallenberg) syndrome

Question 10

Write a short note on Oesophagus and its applied anatomy.

Answer

Extent

  • C6 to T11

Constrictions

  • Cricopharyngeal junction
  • Arch of aorta
  • Left main bronchus
  • Diaphragmatic hiatus

Blood Supply

  • Inferior thyroid artery
  • Aortic branches
  • Left gastric artery

Applied Anatomy

  • Foreign body impaction
  • Oesophageal varices
  • Carcinoma
  • Hiatus hernia

Question 11

Write a short note on Palatine Tonsil and its clinical importance.

Answer

Situation

  • Tonsillar fossa between the palatoglossal and palatopharyngeal arches.

Blood Supply

  • Tonsillar branch of facial artery (chief)
  • Ascending palatine
  • Ascending pharyngeal
  • Dorsal lingual branches

Clinical Importance

  • Tonsillitis
  • Tonsillectomy
  • Risk of haemorrhage
  • Referred ear pain via glossopharyngeal nerve

Question 12

Write a short note on Thoracic Duct and its applied aspects.

Answer

Origin

  • Cisterna chyli (L1–L2)

Course

  • Passes through the aortic hiatus.
  • Ascends in the posterior mediastinum.
  • Terminates at the junction of the left internal jugular and left subclavian veins.

Areas Drained

  • Entire body except the right upper quadrant.

Applied Anatomy

  • Chylothorax
  • Injury during neck surgery
  • Lymphatic obstruction

Question 13

Write a short note on Blood Supply of the Thyroid Gland and its surgical importance.

Answer

Arterial Supply

  • Superior thyroid artery (external carotid artery)
  • Inferior thyroid artery (thyrocervical trunk)
  • Thyroid ima artery (occasionally)

Venous Drainage

  • Superior thyroid vein
  • Middle thyroid vein
  • Inferior thyroid vein

Surgical Importance

  • Ligate the superior thyroid artery close to the gland to avoid injury to the external laryngeal nerve.
  • Ligate the inferior thyroid artery away from the gland to protect the recurrent laryngeal nerve.
  • Care is required to preserve the parathyroid glands during thyroid surgery.