Question 1

Which cranial nerve is the only one that extends beyond the head and neck region?

Accepted Answer

Vagus nerve (X)

Question 2

A patient presents with numbness in the medial aspect of the hand and difficulty flexing the wrist. Which nerve is most likely affected?

Accepted Answer

Ulnar nerve

Question 3

Which of the following statements about spinal nerves is CORRECT?

Accepted Answer

All spinal nerves are mixed nerves containing both sensory and motor fibers.

Question 4

The phrenic nerve, which innervates the diaphragm, arises from which spinal nerve roots?

Accepted Answer

$C_3$ to $C_5$

Question 5

Which nerve plexus is responsible for innervating the anterior thigh muscles, including the quadriceps?

Accepted Answer

Lumbar plexus

Question 6

A patient steps on a sharp object and immediately withdraws their foot while the opposite leg extends to support their weight. Which reflex is being demonstrated?

Accepted Answer

Crossed extensor reflex

Question 7

Damage to the motor cortex or corticospinal tracts can cause a positive Babinski sign. What is the expected response in an adult with this lesion when the lateral aspect of the sole is stroked?

Accepted Answer

Upward extension (dorsiflexion) of the big toe and fanning of other toes

Question 8

Which of the following best describes a dermatome?

Accepted Answer

An area of skin innervated by cutaneous branches of a single spinal nerve

Question 9

Which law states that any nerve serving a muscle that produces movement at a joint also innervates that joint and the skin over it?

Accepted Answer

Hilton's law

Question 10

Which of the following is TRUE regarding the stretch reflex?

Accepted Answer

It is monosynaptic and ipsilateral.

Question 11

If the dorsal root of a spinal nerve is damaged, which function would be most affected?

Accepted Answer

Sensory input from peripheral receptors

Question 12

Which nerve is the longest and thickest in the body, serving the lower limb and composed of tibial and common fibular nerves?

Accepted Answer

Sciatic nerve

Question 13

A patient has lost sensation in the skin over the lateral forearm and has difficulty flexing the elbow. Which nerve is most likely damaged?

Accepted Answer

Musculocutaneous nerve

Question 14

Which of the following is NOT a component of the reflex arc?

Accepted Answer

Cerebral cortex

Question 15

Which spinal nerve roots contribute to the brachial plexus?

Accepted Answer

$C_5$ to $T_1$

Question 16

Which of the following is a function of the tendon reflex?

Accepted Answer

Prevents excessive muscle stretch and damage

Question 17

Which nerve innervates most of the flexors in the forearm, pronators, and muscles for thumb opposition?

Accepted Answer

Median nerve

Question 18

If a patient has a lesion in the corticospinal tract, which superficial reflex is most likely to be absent?

Accepted Answer

Abdominal reflex

Question 19

Which of the following best explains why damage to a single spinal nerve does NOT usually result in complete numbness of a dermatome?

Accepted Answer

Most dermatomes overlap, so adjacent nerves also supply the area.

Question 20

Which of the following is TRUE regarding the organization of the brachial plexus?

Accepted Answer

It gives rise to major nerves such as the musculocutaneous, median, ulnar, radial, and axillary.

Peripheral Nervous System: Cranial and Spinal Nerves, Plexuses, and Reflexes

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