Corticospinal tracts Practice Questions

Question 1

A 25-year-old man comes to the physician for severe back pain. He describes the pain as shooting and stabbing. On a 10-point scale, he rates the pain as a 9 to 10. The pain started after he lifted a heavy box at work; he works at a supermarket and recently switched from being a cashier to a storekeeper. The patient appears to be in severe distress. Vital signs are within normal limits. On physical examination, the spine is nontender without paravertebral muscle spasms. Range of motion is normal. A straight-leg raise test is negative. After the physical examination has been completed, the patient asks for a letter to his employer attesting to his inability to work as a storekeeper. Which of the following is the most appropriate response?

Accepted Answer

I understand that you are uncomfortable, but the findings do not match the severity of your symptoms. Let's talk about the recent changes at your job.

Answer

“Yes. Since work may worsen your condition, I would prefer that you stay home a few days. I will write a letter to your employer to explain the situation.”

Answer

You say you are in severe pain. However, the physical examination findings do not suggest a physical problem that can be addressed with medications or surgery. I'd like to meet on a regular basis to see how you're doing.

Answer

The physical exam findings do not match your symptoms, which suggests a psychological problem. I would be happy to refer you to a mental health professional.

Answer

The physical exam findings suggest a psychological rather than a physical problem. But there is a good chance that we can address it with cognitive-behavioral therapy.

Question 2

A 78-year-old woman is accompanied by her family for a routine visit to her primary care provider. The family states that 5 months prior, the patient had a stroke and is currently undergoing physical therapy. Today, her temperature is 98.2°F (36.8°C), blood pressure is 112/72 mmHg, pulse is 64/min, and respirations are 12/min. On exam, she is alert and oriented with no deficits in speech. Additionally, her strength and sensation are symmetric and preserved bilaterally. However, on further neurologic testing, she appears to have some difficulty with balance and a propensity to fall to her right side. Which of the following deficits does the patient also likely have?

Accepted Answer

Truncal ataxia

Answer

Hemiballismus

Answer

Hemispatial neglect

Answer

Intention tremor

Answer

Contralateral eye deviation

Question 3

An epidemiologist is evaluating the efficacy of Noxbinle in preventing HCC deaths at the population level. A clinical trial shows that over 5 years, the mortality rate from HCC was 25% in the control group and 15% in patients treated with Noxbinle 100 mg daily. Based on this data, how many patients need to be treated with Noxbinle 100 mg to prevent, on average, one death from HCC?

Accepted Answer

10

Answer

20

Answer

73

Answer

50

Answer

100

Question 4

A 40-year-old man is brought to the emergency department after sustaining multiple lacerations during a bar fight. The patient’s wife says that he has been showing worsening aggression and has been involved in a lot of arguments and fights for the past 2 years. The patient has no significant past medical or psychiatric history and currently takes no medications. The patient cannot provide any relevant family history since he was adopted as an infant. His vitals are within normal limits. On physical examination, the patient looks apathetic and grimaces repeatedly. Suddenly, his arms start to swing by his side in an uncontrolled manner. Which area of the brain is most likely affected in this patient?

Accepted Answer

Caudate nucleus

Answer

Cerebral cortex

Answer

Cerebellum

Answer

Medulla oblongata

Answer

Substantia nigra

Question 5

A 21-year-old man was involved in a motor vehicle accident and died. At autopsy, the patient demonstrated abnormally increased mobility at the neck. A section of cervical spinal cord at C6 was removed and processed into slides. Which of the following gross anatomic features is most likely true of this spinal cord level?

Accepted Answer

Cuneate and gracilis fasciculi are present

Answer

Least amount of white matter

Answer

Prominent lateral horns

Answer

Absence of gray matter enlargement

Answer

Involvement with parasympathetic nervous system

Question 6

A 80-year-old man is brought to the emergency department with complaints that he "can't control his left leg". His symptoms started a few hours ago. He was outside taking a walk with his wife when suddenly his leg shot out and kicked her. His past medical history is notable for diabetes, hypertension, and a myocardial infarction 5 years ago. He smokes 1-2 cigarettes/day. He does not use alcohol or illicit drugs. On exam, the patient has intermittent wide, flinging movements that affect his proximal left arm and left leg. Which of the following parts of his brain is most likely damaged?

Accepted Answer

Right subthalamic nucleus

Answer

Ventral posterior thalamic nucleus

Answer

Left internal capsule

Answer

Left subthalamic nucleus

Answer

Right internal capsule

Question 7

You are currently employed as a clinical researcher working on clinical trials of a new drug to be used for the treatment of Parkinson's disease. Currently, you have already determined the safe clinical dose of the drug in a healthy patient. You are in the phase of drug development where the drug is studied in patients with the target disease to determine its efficacy. Which of the following phases is this new drug currently in?

Accepted Answer

Phase 2

Answer

Phase 4

Answer

Phase 1

Answer

Phase 0

Answer

Phase 3

Question 8

A 61-year-old man is brought to the emergency department by his son after collapsing to the ground while at home. His son immediately performed cardiopulmonary resuscitation and later the patient underwent successful defibrillation after being evaluated by the emergency medical technician. The patient has a medical history of hypertension, hyperlipidemia, and type II diabetes mellitus. He has smoked one-half pack of cigarettes for approximately 30 years. The patient was admitted to the cardiac intensive care unit, and after a few days developed acute onset right upper extremity weakness. His temperature is 99°F (37.2°C), blood pressure is 145/91 mmHg, pulse is 102/min and irregularly irregular, and respirations are 16/min. On physical examination, the patient is alert and orientated to person, place, and time. His language is fluent and he is able to name, repeat, and read. His strength is 5/5 throughout except in the right hand, wrist, and arm, which is 2/5. Based on this patient's clinical presentation, the affected neuronal fibers decussate at which level of the central nervous system?

Accepted Answer

Caudal medulla

Answer

Pons

Answer

Spinal cord

Answer

Primary motor cortex

Answer

Thalamus

Question 9

Arrange in sequence the structures involved in the direct pathway (1=Striatum, 2=GPi, 3=Thalamus, 4=Cortex output, 5=Cortex input):-

Accepted Answer

5,1,2,3,4

Answer

1,3,4,2,5

Answer

1,2,3,4,5

Answer

5,4,2,3,1

Answer

5,1,3,2,4

Question 10

A 12-year-old boy is brought to his orthopedic surgeon for evaluation of leg pain and positioning. Specifically, over the past several months he has been complaining of thigh pain and has more difficulty sitting in his wheelchair. His medical history is significant for spastic quadriplegic cerebral palsy since birth and has undergone a number of surgeries for contractures in his extremities. At this visit his legs are found to be scissored such that they cross each other at the knees and are difficult to separate. Surgery is performed and the boy is placed into a cast that keeps his legs abducted to prevent scissoring. Overactivity of the muscles innervated by which of the following nerves is most consistent with this patient's deformity?

Accepted Answer

Obturator nerve

Answer

Nerve to the iliopsoas

Answer

Sciatic nerve

Answer

Femoral nerve

Answer

Superior gluteal nerve

Corticospinal tracts

Study Resources

Lessons

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Lessons

Origin and course of lateral corticospinal tract

Origin and course of anterior corticospinal tract

Upper motor neuron anatomy

Lower motor neuron anatomy

Decussation of pyramids

Somatotopic organization

Alternative motor pathways

UMN vs LMN lesions

Spinal cord injury levels and their effects

Clinical testing of corticospinal tract function

Practice Questions

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About Corticospinal tracts for USMLE

Lessons in Corticospinal tracts

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