Neuromuscular and Nervous Systems Flashcards

A patient presents with foot drop, weakness of ankle dorsiflexion, and sensory loss over the dorsum of the foot. Which nerve is most likely injured?

Answer: Common peroneal nerve

The common peroneal nerve innervates the muscles responsible for ankle dorsiflexion and eversion, and provides sensation to the dorsum of the foot.

Which reflex arc component is responsible for detecting changes in muscle length?

Answer: Muscle spindle

Muscle spindles (intrafusal fibers) are stretch-sensitive receptors that detect changes in muscle length and rate of length change.

A patient recovering from a stroke demonstrates hyperreflexia and increased muscle tone in the right upper extremity. Which descending pathway is most likely damaged?

Answer: Corticospinal tract

Damage to the corticospinal (pyramidal) tract causes upper motor neuron signs including hyperreflexia, spasticity, and increased muscle tone.

Which cranial nerve is tested when a patient is asked to shrug their shoulders against resistance?

Answer: CN XI

The accessory nerve (CN XI) innervates the trapezius and sternocleidomastoid muscles, which are tested with shoulder shrugging and head rotation.

During gait analysis, a patient shows excessive lateral trunk lean toward the stance leg. This compensatory strategy is most likely due to weakness of which muscle?

Answer: Gluteus medius

Gluteus medius weakness causes the Trendelenburg gait, where the trunk leans toward the weak side to shift the center of mass and reduce the hip abductor moment demand.

A patient with a C6 spinal cord injury would retain which of the following motor functions?

Answer: Wrist extension

The C6 myotome includes wrist extensors (extensor carpi radialis), which remain intact in a C6 complete spinal cord injury.

Which term describes the phenomenon where repeated stimulation of a reflex leads to a diminished response over time?

Answer: Habituation

Habituation is the progressive decrease in reflex response amplitude with repeated, non-noxious stimulation of the same pathway.

A patient demonstrates an inability to oppose the thumb and has wasting of the thenar eminence. Which nerve is most likely compressed?

Answer: Median nerve at the wrist

Carpal tunnel syndrome involves median nerve compression at the wrist, causing thenar wasting and loss of thumb opposition due to opponens pollicis weakness.

Which area of the brain is primarily responsible for the learning and coordination of skilled, sequential movements?

Answer: Cerebellum

The cerebellum coordinates the timing, sequencing, and precision of skilled voluntary movements and is critical for motor learning.

A patient presents with a positive Romberg test. What does this finding indicate?

Answer: Proprioceptive deficit with visual compensation

A positive Romberg test indicates that the patient can maintain balance with eyes open (using vision) but loses balance with eyes closed, suggesting proprioceptive or dorsal column impairment.

Which type of motor neuron disease is characterized by both upper and lower motor neuron signs occurring simultaneously?

Answer: Amyotrophic lateral sclerosis

ALS (amyotrophic lateral sclerosis) is characterized by simultaneous degeneration of both upper motor neurons (corticospinal tract) and lower motor neurons (anterior horn cells).

A therapist observes fasciculations and muscle atrophy in a patient's right quadriceps. These findings are most consistent with a lesion of which structure?

Answer: Lower motor neuron

Fasciculations and muscle atrophy are classic lower motor neuron signs resulting from denervation of the muscle.

A patient with Parkinson's disease demonstrates difficulty initiating movements. This symptom is referred to as:

Answer: Akinesia

Akinesia refers to difficulty or absence of voluntary movement initiation, a hallmark motor symptom of Parkinson's disease due to dopamine depletion in the basal ganglia.

The Tinel's sign at the medial elbow (cubital tunnel) tests for entrapment of which nerve?

Answer: Ulnar nerve

Tinel's sign at the cubital tunnel (medial elbow) reproduces paresthesias in the ulnar nerve distribution when the nerve is tapped at the site of entrapment.

Which spinal cord tract carries conscious proprioception and vibration sense to the brain?

Answer: Dorsal columns (posterior funiculus)

The dorsal columns (medial lemniscal pathway) carry fine touch, vibration, and conscious proprioception to the sensory cortex via the thalamus.

A patient who had a right middle cerebral artery stroke now has left-sided hemiplegia and left homonymous hemianopia. The hemianopia is caused by damage to which structure?

Answer: Right optic radiation

The right optic radiation carries visual information from the left visual field; damage causes left homonymous hemianopia contralateral to the side of the MCA stroke.

Which finding would differentiate a peripheral vestibular disorder from a central vestibular disorder in a patient with dizziness?

Answer: Nystagmus that changes direction with gaze

Direction-changing nystagmus with gaze is a hallmark of central vestibular pathology; peripheral vestibular nystagmus is unidirectional and suppressed by visual fixation.

A patient with a T10 complete spinal cord injury would be expected to have intact function at which level?

Answer: Both A and B

T10 is above the lumbar plexus, so hip flexors (L1-L3) and knee extensors (L2-L4) would both be paralyzed; however, T10 and above innervated trunk muscles are intact.

Which assessment tool is most appropriate for measuring functional mobility and fall risk in a patient with neurological deficits?

Answer: Berg Balance Scale

The Berg Balance Scale is a validated 14-item functional balance assessment widely used to quantify balance ability and predict fall risk in neurological populations.

A patient demonstrates athetosis. Which structure is most likely damaged?

Answer: Basal ganglia (putamen)

Athetosis (slow, writhing, involuntary movements) results from damage to the putamen component of the basal ganglia and is commonly seen in cerebral palsy.