Anatomy
4 questionsName the muscle marked as colour blue in the extensor compartment of forearm. (Recent NEET Pattern 2019)
Identify the structure shown. (Recent NEET Pattern 2019)
The dermatome level of the structure indicated in the image is: (Recent NEET Pattern 2019)
Which nerve supplies the highlighted muscle? (Recent NEET Pattern 2019)
NEET-PG 2019 - Anatomy NEET-PG Practice Questions and MCQs
Question 291: Name the muscle marked as colour blue in the extensor compartment of forearm. (Recent NEET Pattern 2019)
- A. Extensor carpi radialis
- B. Brachioradialis (Correct Answer)
- C. Extensor digitorum
- D. Extensor carpi ulnaris
Explanation: ***Brachioradialis*** - The **brachioradialis** muscle is a prominent superficial muscle in the lateral compartment of the forearm, shown in **blue** in the diagram, originating from the **lateral supracondylar ridge of the humerus** and inserting into the **radial styloid process**. - It primarily functions to **flex the elbow** and helps to bring the forearm into a midprone position. *Extensor carpi radialis* - The extensor carpi radialis muscles (longus and brevis) are located deep to the brachioradialis and extend the wrist, often distinguishable by their more distal insertion on the **metacarpals**. - They are typically not the most superficial and most lateral muscle spanning the entire forearm length as depicted in blue. *Extensor digitorum* - The **extensor digitorum** is located more medially than the brachioradialis and its tendons diverge to attach to the four medial fingers, a configuration not shown by the blue muscle. - This muscle is responsible for **extending the medial four digits**. *Extensor carpi ulnaris* - The **extensor carpi ulnaris** is situated on the **ulnar side** of the forearm, furthest from the blue-highlighted muscle, and its primary action is **wrist extension and ulnar deviation**. - It would be found along the posterior medial aspect of the forearm, not in the relatively lateral position shown in blue.
Question 292: Identify the structure shown. (Recent NEET Pattern 2019)
- A. Cerebellum (Correct Answer)
- B. Pons
- C. Medulla
- D. Occipital cortex
Explanation: ***Cerebellum*** - The arrow in the sagittal MRI view points to the posterior cranial fossa, where the **cerebellum** is located, characterized by its distinctive folia and fissures. - The cerebellum is critical for **motor control**, balance, coordination, and learning motor skills. *Pons* - The **pons** is located anterior to the cerebellum, appearing as a prominent bulge on the brainstem, superior to the medulla. - It primarily acts as a communication bridge between the **cerebrum and cerebellum** and contains nuclei important for sleep, respiration, and bladder control. *Medulla* - The **medulla oblongata** is the lowest part of the brainstem, continuous with the spinal cord, situated inferior to the pons. - It contains vital autonomic centers for **cardiac, respiratory, and vasomotor functions**. *Occipital cortex* - The **occipital cortex** is part of the cerebrum, located at the posterior pole of the brain, superior to the cerebellum, and is responsible for **visual processing**. - It is identifiable by its characteristic gyri and sulci, distinctly different from the highly folded cerebellar folia.
Question 293: The dermatome level of the structure indicated in the image is: (Recent NEET Pattern 2019)
- A. T10 (Correct Answer)
- B. T12
- C. L1
- D. L3-L4
Explanation: ***T10*** - The dermatome for **T10** corresponds to the level of the **umbilicus**. - This is a crucial anatomical landmark for dermatomal assessment, neurological examination, and clinical correlation. - The T10 dermatome is consistently tested in NEET-PG examinations. *T12* - The dermatome for **T12** is located just inferior to the umbilicus, typically corresponding to the **suprapubic region** or inguinal area. - It does not correspond to the umbilicus itself. *L1* - The dermatome for **L1** is generally located in the **inguinal region** and upper anterior thigh. - This is significantly lower than the umbilicus. *L3-L4* - **L3-L4** refers to a **vertebral level**, not a dermatomal level. - While the umbilicus is anatomically located at approximately the L3-L4 vertebral level, the question asks for the **dermatome**, which is T10. - Dermatomes and vertebral levels should not be confused.
Question 294: Which nerve supplies the highlighted muscle? (Recent NEET Pattern 2019)
- A. Median Nerve
- B. Ulnar nerve
- C. Radial Nerve
- D. Anterior interosseous nerve (Correct Answer)
Explanation: ***Anterior interosseous nerve*** - The highlighted muscle is the **flexor pollicis longus**, which is innervated by the **anterior interosseous nerve**, a branch of the **median nerve**. - This muscle is responsible for **flexion of the interphalangeal joint of the thumb**. *Median Nerve* - While the anterior interosseous nerve is a branch of the median nerve, the median nerve itself innervates most of the **forearm flexors** and thenar muscles, but not directly the flexor pollicis longus by its main trunk. - Damage to the median nerve would affect the flexor pollicis longus, but the direct innervation is via its specific branch. *Ulnar nerve* - The ulnar nerve supplies most of the **intrinsic hand muscles** (except for the thenar muscles and first two lumbricals) and the **flexor carpi ulnaris** and medial half of the **flexor digitorum profundus**. - It does not innervate the flexor pollicis longus. *Radial Nerve* - The radial nerve primarily innervates the **extensor muscles** of the arm and forearm. - It has no role in the innervation of the flexor pollicis longus or other anterior compartment forearm muscles.