MBBS Anatomy 1 — Questions and Answers
Question 1: Which nerve is most commonly injured in a midshaft fracture of the humerus?
- Ulnar nerve
- Radial nerve (Correct answer)
- Median nerve
- Musculocutaneous nerve
Correct answer: Radial nerve
The radial nerve winds around the posterior aspect of the humerus in the spiral groove and is vulnerable to injury in midshaft humeral fractures.
Question 2: The anatomical snuffbox is bounded laterally by which tendons?
- Extensor pollicis longus and brevis
- Abductor pollicis longus and extensor pollicis brevis (Correct answer)
- Flexor pollicis longus and abductor pollicis brevis
- Extensor indicis and extensor pollicis longus
Correct answer: Abductor pollicis longus and extensor pollicis brevis
The lateral border of the anatomical snuffbox is formed by the tendons of abductor pollicis longus and extensor pollicis brevis.
Question 3: Which structure passes through the foramen ovale of the skull base?
- CN V2 (maxillary nerve)
- CN V3 (mandibular nerve) (Correct answer)
- CN VI (abducens nerve)
- Middle meningeal artery
Correct answer: CN V3 (mandibular nerve)
The mandibular division of the trigeminal nerve (CN V3) passes through the foramen ovale.
Question 4: The femoral triangle is bounded superiorly by which structure?
- Inguinal ligament (Correct answer)
- Sartorius muscle
- Adductor longus muscle
- Poupart's ligament
Correct answer: Inguinal ligament
The inguinal ligament forms the superior boundary of the femoral triangle.
Question 5: Which of the following is a content of the carotid sheath?
- Internal jugular vein, common carotid artery, vagus nerve (Correct answer)
- External carotid artery, internal jugular vein, phrenic nerve
- Common carotid artery, subclavian vein, vagus nerve
- Internal carotid artery, external jugular vein, glossopharyngeal nerve
Correct answer: Internal jugular vein, common carotid artery, vagus nerve
The carotid sheath contains the common carotid artery, internal jugular vein, and vagus nerve (CN X).
Question 6: Which dermatome covers the medial aspect of the thigh?
- L1
- L2 (Correct answer)
- L3
- S1
Correct answer: L2
The L2 dermatome covers the medial and anterior aspect of the upper thigh.
MBBS Anatomy 1
Which nerve is most commonly injured in a midshaft fracture of the humerus?