ABEM ABEM Anatomy & Neurophysiology 2

Question 1

Which muscle is the primary abductor of the thumb and is commonly tested in thenar EMG?

Accepted Answer

Abductor pollicis brevis

Answer

The abductor pollicis brevis is the most superficial thenar muscle and is the primary target for median nerve EMG assessment.

Question 2

The sural nerve is formed by contributions from which two nerves?

Accepted Answer

Tibial and common peroneal nerves

Answer

The sural nerve is formed by the medial sural cutaneous nerve (from tibial) and the peroneal communicating branch (from common peroneal nerve).

Question 3

Which segment of the spinal cord is responsible for the Achilles tendon reflex?

Accepted Answer

S1-S2

Answer

The Achilles tendon reflex is mediated primarily by the S1 nerve root, with S2 contribution in some individuals.

Question 4

The lateral femoral cutaneous nerve exits the pelvis near which anatomical landmark?

Accepted Answer

Inguinal ligament near ASIS

Answer

The lateral femoral cutaneous nerve passes under or through the inguinal ligament near the anterior superior iliac spine, where it can be compressed.

Question 5

What is the functional consequence of demyelination on nerve conduction velocity?

Accepted Answer

Conduction velocity decreases

Answer

Demyelination disrupts saltatory conduction, forcing the action potential to travel continuously along the axon, markedly slowing conduction velocity.

(ABEM) American Board of Electrodiagnostic Medicine Practice Test

(ABEM) American Board of Electrodiagnostic Medicine Practice Test

ABEM ABEM Anatomy & Neurophysiology 2