USMLE Step 1 Qs (3)
Questions from various sources for practicing
- 1.The process of unlocking the fully extended knee in preparation for flexion requires initial contraction of which of the following muscles?
- A.
Gastrocnemius, soleus, and plantaris muscles
- B.
Hamstring muscles
- C.
Popliteus muscle
- D.
Quadriceps femoris muscle
- E.
Sartorius muscle and short head of the biceps femoris muscle
- 2.
A 22-year-old male who belongs to a weekend football league presents in the ER. He was running with the ball when a defender tackled him in the midthigh. The patient reports that when he got up, his thigh hurt, so he sat out the rest of the game. When walking to the car, his posterior thigh was extremely painful and swollen. After his shower, he noticed it was becoming discolored with increased swelling. You are concerned about the presence of a hematoma and a disruption of the arterial blood flow to the hamstring muscles. An arteriogram is performed and the vessels in question (arrows) show good filling by contrast. These blood vessels are- A.
Descending branches of the inferior gluteal artery
- B.
Perforating branches of the deep femoral artery
- C.
Perforating branches from the obturator artery
- D.
Perforating branches of the femoral artery
- E.
Posterior femoral artery
- 3.The muscles of the anterior compartment of the leg are innervated primarily by which of the following nerves?
- A.
Deep fibular
- B.
Lateral sural cutaneous
- C.
Saphenous
- D.
Superficial fibular
- E.
Sural
- 4.The tendon of which of the following muscles is involved when the tuberosity of the fifth metatarsal bone is avulsed in an inversion fracture?
- A.
Abductor digiti minimi
- B.
Peroneus brevis
- C.
Peroneus longus
- D.
Tibialis anterior
- E.
Tibialis posterior
- 5.In a presurgical patient, the great saphenous vein was cannulated in the vicinity of the ankle. During the procedure, the patient experienced severe pain that radiated along the medial border of the foot. Which of the following nerves was accidentally included in a ligature during this procedure?
- A.
Medial femoral cutaneous nerve
- B.
Saphenous nerve
- C.
Superficial fibular nerve
- D.
Sural cutaneous nerve
- E.
Tibial nerve
- 6.
A 22-year-old male who belongs to a weekend football league was running with the ball when a defender tackled him mid-lower limb from the side. After the tackle, he felt that the knee was hurt and went to the emergency room. From an MRI of the knee, the lateral meniscus is uniformly black; however, the medial meniscus has a tear (lucent area within the meniscus). Which of the following is the reason why the medial meniscus is more susceptible to damage than the lateral meniscus?
- A.
The medial meniscus is attached to the popliteus muscle tendon, which can move into a position making it more susceptible.
- B.
The medial meniscus is attached to the medial (tibial) collateral ligament, which holds it relatively immobile, making it more susceptible.
- C.
The medial meniscus is attached to the anterior cruciate ligament, which holds it relatively immobile, making it more susceptible.
- D.
The only reason the medial meniscus is more susceptible to damage is that the knee usually gets hit laterally, causing more torsion on the medial meniscus.
- 7.A physician examines a patient who complains of pain and paresthesia in the left leg. The distribution of the pain—running down the medial aspect of the leg and the medial side of the foot and including the great toe—is suggestive of a herniated intervertebral disk. The physician links the distribution of symptoms with nerve L4 and concludes that herniation has occurred at which location?
- A.
L3–L4 intervertebral disk
- B.
L4–L5 intervertebral disk
- C.
L5–S1 intervertebral disk
- D.
S1–S2 intervertebral disk
- E.
Insufficient data to determine
- 8.
Refer to the photomicrographs below in answering these questions. The low-magnification micrograph is on top and is from the same organ as the high-magnification micrograph located below it. In the top panel, the cells located in the region marked with the asterisk and those in the region delineated with the star and dashes have which of the following characteristics in common?
- A.
Embryologic origin from intermediate mesoderm
- B.
Storage of appreciable quantities of product
- C.
Dependence on anterior pituitary regulation
- D.
Are essential for life
- E.
Release of stress-related hormones
- 9.
Refer to the photomicrographs below in answering these questions. The low-magnification micrograph is on top and is from the same organ as the high-magnification micrograph located below it. In Addison's disease, which of the following would be a direct effect of the disease?
- A.
Hypertrophy of zone A only
- B.
Hypertrophy of zones A, B, and C only
- C.
Hypotrophy of zones A, B, and C only
- D.
Hypotrophy of zones A, B, C, and D only
- E.
Hypertrophy of zones A and B only
- 10.
The activity of the cell labeled with the star is regulated by which of the following?
- A.
Follicle-stimulating hormone (FSH)
- B.
Luteinizing hormone (LH)
- C.
FSH releasing factor
- D.
Inhibin
- E.
Androgen-binding protein
- 11.
Which of the following statements correctly describes the cells marked with asterisks?
- A.
They divide during each wave of spermatogenic cell division
- B.
They are found in a 1:1 relationship with spermatogonia, spermatocytes, and spermatids
- C.
They undergo spermatocytogenesis to form spermatocytes
- D.
They undergo meiosis and and produce the haploid number associated with the gametes
- E.
They form tight junctions with each other to establish the blood-testis barrier
- 12.A 53-year-old woman has a paralysis of the right side of her face that produces an expressionless and drooping appearance. She is unable to close her right eye, has difficulty chewing and drinking, perceives sounds as annoyingly intense in her right ear, and experiences some pain in her right external auditory meatus. Physical examination reveals loss of the blink reflex in the right eye on stimulation of either cornea and loss of taste from the anterior two-thirds of the tongue on the right. Lacrimation appears normal in the right eye, the jaw-jerk reflex is normal, and there appears to be no problem with balance. The inability to close the right eye is the result of involvement of which of the following?
- A.
Zygomatic branch of the facial nerve
- B.
Buccal branch of the trigeminal nerve
- C.
Levator palpebrae superioris muscle
- D.
Superior tarsal muscle (of Müller)
- E.
Orbital portion of the orbicularis oculi muscle
- 13.A 53-year-old woman has a paralysis of the right side of her face that produces an expressionless and drooping appearance. She is unable to close her right eye, has difficulty chewing and drinking, perceives sounds as annoyingly intense in her right ear, and experiences some pain in her right external auditory meatus. Physical examination reveals loss of the blink reflex in the right eye on stimulation of either cornea and loss of taste from the anterior two-thirds of the tongue on the right. Lacrimation appears normal in the right eye, the jaw-jerk reflex is normal, and there appears to be no problem with balance. Which of the following is the branch of the facial nerve that conveys secretomotor neurons involved in lacrimation?
- A.
Chorda tympani
- B.
Deep petrosal nerve
- C.
Greater superficial petrosal nerve
- D.
Lacrimal nerve
- E.
Lesser superficial petrosal nerve
- 14.A 70-year-old woman is seen in Outpatient Neurology complaining of strange feelings and numbness in both lower extremities below the knees. She walked with a wide-based gait, slamming her right foot down heavily and dragging her left foot. Subsequent examination revealed diminished two-point discrimination, proprioception, and vibratory senses, especially below the knees. Pain and temperature sensations were intact. Motor examination revealed hyperactive knee and ankle-jerk reflexes with spastic weakness most obvious on the left. The patient tended to tilt to the left when standing with her eyes closed. The afferent fibers involved in this case ascend in the spinal cord in which of the following?
- A.
Lateral spinothalamic tract
- B.
Cuneate fasciculus
- C.
Cuneocerebellar tract
- D.
Anterior spinothalamic tract
- E.
Fasciculus gracilis
- 15.A 70-year-old woman is seen in Outpatient Neurology complaining of strange feelings and numbness in both lower extremities below the knees. She walked with a wide-based gait, slamming her right foot down heavily and dragging her left foot. Subsequent examination revealed diminished two-point discrimination, proprioception, and vibratory senses, especially below the knees. Pain and temperature sensations were intact. Motor examination revealed hyperactive knee and ankle-jerk reflexes with spastic weakness most obvious on the left. The patient tended to tilt to the left when standing with her eyes closed. Further studies revealed that the patient's symptoms were due to a chronic vitamin B12 deficiency (pernicious anemia). This results in decreased activity of B12-dependent enzymes, including methylmalonic CoA mutase, essential for maintenance of myelin sheaths. Demyelinization in which of the following motor pathways would produce the observed symptoms?
- A.
Lateral corticospinal tract
- B.
Vestibulospinal tract
- C.
Lower motor neurons (ventral horn cells)
- D.
Rubrospinal tract
- E.
Tectospinal tract
- 16.A mammogram of a woman, age 48, reveals macrocalcification within the right breast, indicating the need for biopsy. The surgeon visually and manually examines the breast with negative results. The surgeon closely examines the nipple for indications of ductal carcinoma. At surgery for the biopsy, a locator needle is inserted into the region of macrocalcification and the position confirmed by mammography. The surgeon incised the skin and dissected a block of tissue about the needle. The pathology report indicated ductal carcinoma with microinvasion necessitating surgery. Both patient and surgeon agreed that a modified radical mastectomy offered the best prognosis in her case. At surgery for mastectomy, the surgeon carries the dissection along the major pathway of lymphatic drainage from the mammary gland. The major lymphatic channels parallel which of the following?
- A.
Subcutaneous venous networks to the contralateral breast and abdominal wall
- B.
Tributaries of the axillary vessels to the axillary nodes
- C.
Tributaries of the intercostal vessels to the parasternal nodes
- D.
Tributaries of the internal thoracic (mammary) vessels to the parasternal nodes
- E.
Tributaries of the thoracoacromial vessels to the apical (subscapular) nodes
- 17.A mammogram of a woman, age 48, reveals macrocalcification within the right breast, indicating the need for biopsy. The surgeon visually and manually examines the breast with negative results. The surgeon closely examines the nipple for indications of ductal carcinoma. At surgery for the biopsy, a locator needle is inserted into the region of macrocalcification and the position confirmed by mammography. The surgeon incised the skin and dissected a block of tissue about the needle. The pathology report indicated ductal carcinoma with microinvasion necessitating surgery. Both patient and surgeon agreed that a modified radical mastectomy offered the best prognosis in her case. At surgery for mastectomy, the surgeon carries the dissection along the major pathway of lymphatic drainage from the mammary gland. The surgery appears to have been successful. However, the patient is found to have winging of the scapula when the flexed arm is pressed against a fixed object. This indicates injury to which of the following nerves?
- A.
Axillary
- B.
Long thoracic
- C.
Lower subscapular
- D.
Supraclavicular
- E.
Thoracodorsal
- 18.A firefighter, age 34 and a nonsmoker, complains of bouts of dizziness at times of intense exertion. His history reveals having been exposed to intense smoke six months ago when his breathing apparatus malfunctioned during a job. He is scheduled for a pulmonary function test. Regarding the "pump handle" movement during respiration, which of the following statements is correct?
- A.
There is a decrease in the anterior-posterior diameter of the chest
- B.
No movement occurs at the costovertebral joints
- C.
There is an increase in the superior-inferior diameter of the chest
- D.
Movement occurs at the sternomanubrial joint
- E.
The primary change in dimension of the chest occurs in the transverse diameter
- 19.A firefighter, age 34 and a nonsmoker, complains of bouts of dizziness at times of intense exertion. His history reveals having been exposed to intense smoke six months ago when his breathing apparatus malfunctioned during a job. He is scheduled for a pulmonary function test. When the patient was asked to exhale forcibly and maximally, the volume of expiration was constant but the rate of flow was diminished, indicating airway constriction likely due to bronchospasm. The smooth muscle of the bronchial airways is innervated by which of the following nerves?
- A.
Intercostal nerves
- B.
Phrenic nerves
- C.
Thoracic splanchnic nerves
- D.
Vagus nerve
- 20.A 36-year-old male office worker comes to the clinic complaining of general weakness and shortness of breath. He also relates a rapid, throbbing pulse after climbing a flight of stairs. Which of the following correctly pertains to normal mitral valve function?
- A.
The papillary muscles are rudimentary and have no major function
- B.
It prevents regurgitation of blood during ventricular relaxation
- C.
The chordae tendineae and papillary muscles prevent eversion of the valve cusps
- D.
The papillary muscles contract to close the valve
- 21.A 64-year-old man is brought into the emergency room after experiencing more than 3 h of increasing chest pain that was unrelieved by rest, antacids, or nitroglycerin. He complains of nausea without vomiting. Further questioning reveals a two-year history of exertional angina pectoris (pressing chest pain that often radiated along the inner aspect of the left arm when the patient climbed one flight of stairs). Propranolol, which reduces the response of the heart to stress, and nitroglycerin, which dilates systemic veins as well as coronary arteries, had been prescribed previously. On physical examination he is found to be acyanotic (normal blood oxygenation), tachypneic (rapid breathing), tachycardiac (rapid pulse rate) with a regular rhythm, and diaphoretic (sweating). This patient's tachycardia probably is mediated by reflex arcs associated with decreased cardiac output and possibly reduced blood pressure. The visceral efferent (motor) pathway of this cardiac response is mediated by which of the following?
- A.
Carotid branches of the glossopharyngeal nerves
- B.
Greater splanchnic nerves
- C.
Phrenic nerves
- D.
Sympathetic cervical and thoracic cardiac fibers
- E.
Vagus and recurrent laryngeal nerves
- 22.A 64-year-old man is brought into the emergency room after experiencing more than 3 h of increasing chest pain that was unrelieved by rest, antacids, or nitroglycerin. He complains of nausea without vomiting. Further questioning reveals a two-year history of exertional angina pectoris (pressing chest pain that often radiated along the inner aspect of the left arm when the patient climbed one flight of stairs). Propranolol, which reduces the response of the heart to stress, and nitroglycerin, which dilates systemic veins as well as coronary arteries, had been prescribed previously. On physical examination he is found to be acyanotic (normal blood oxygenation), tachypneic (rapid breathing), tachycardiac (rapid pulse rate) with a regular rhythm, and diaphoretic (sweating). In angina pectoris, the pain radiating down the left arm is mediated by increased activity in afferent (sensory) fibers contained in which of the following?
- A.
Carotid branch of the glossopharyngeal nerves
- B.
Greater splanchnic nerves
- C.
Phrenic nerves
- D.
Thoracic splanchnic nerves
- E.
Vagus nerve and recurrent laryngeal nerves
- 23.
A 64-year-old man is brought into the emergency room after experiencing more than 3 h of increasing chest pain that was unrelieved by rest, antacids, or nitroglycerin. He complains of nausea without vomiting. Further questioning reveals a two-year history of exertional angina pectoris (pressing chest pain that often radiated along the inner aspect of the left arm when the patient climbed one flight of stairs). Propranolol, which reduces the response of the heart to stress, and nitroglycerin, which dilates systemic veins as well as coronary arteries, had been prescribed previously. On physical examination he is found to be acyanotic (normal blood oxygenation), tachypneic (rapid breathing), tachycardiac (rapid pulse rate) with a regular rhythm, and diaphoretic (sweating). The patient is admitted to a coronary care unit for tests and observation. An electrocardiogram reveals a pattern consistent with a small ventricular posteroseptal infarct from ischemic necrosis that resulted from inadequate blood supply. In the diagram of a normal heart shown below, the coronary artery most likely to be involved in a posteroseptal infarct (as in this patient) is indicated by which letter?
- A.
A
- B.
B
- C.
C
- D.
D
- E.
E
- 24.A 64-year-old man is brought into the emergency room after experiencing more than 3 h of increasing chest pain that was unrelieved by rest, antacids, or nitroglycerin. He complains of nausea without vomiting. Further questioning reveals a two-year history of exertional angina pectoris (pressing chest pain that often radiated along the inner aspect of the left arm when the patient climbed one flight of stairs). Propranolol, which reduces the response of the heart to stress, and nitroglycerin, which dilates systemic veins as well as coronary arteries, had been prescribed previously. On physical examination he is found to be acyanotic (normal blood oxygenation), tachypneic (rapid breathing), tachycardiac (rapid pulse rate) with a regular rhythm, and diaphoretic (sweating). To improve the blood flow to the interventricular septum, a coronary bypass procedure is elected. During surgery the anterior interventricular artery is located and prepared to receive a graft. Which of the following is the vessel lying adjacent to the anterior interventricular artery?
- A.
Anterior cardiac vein
- B.
Coronary sinus
- C.
Great cardiac vein
- D.
Middle cardiac vein
- E.
Small cardiac vein
- 25.A 64-year-old man is brought into the emergency room after experiencing more than 3 h of increasing chest pain that was unrelieved by rest, antacids, or nitroglycerin. He complains of nausea without vomiting. Further questioning reveals a two-year history of exertional angina pectoris (pressing chest pain that often radiated along the inner aspect of the left arm when the patient climbed one flight of stairs). Propranolol, which reduces the response of the heart to stress, and nitroglycerin, which dilates systemic veins as well as coronary arteries, had been prescribed previously. On physical examination he is found to be acyanotic (normal blood oxygenation), tachypneic (rapid breathing), tachycardiac (rapid pulse rate) with a regular rhythm, and diaphoretic (sweating). A section of superficial vein removed from the lower portion of the patient's leg is grafted from the aorta to the coronary artery just distal to the site of occlusion. In coronary bypass surgery, which of the following statements is true?
- A.
The proximal end of the vein is anastomosed to the aorta
- B.
The distal end of the vein is anastomosed to the aorta
- C.
The orientation is unimportant because aortic pressure is always higher than venous pressure
- D.
The orientation is unimportant because the vein is being used as an artery
- E.
The orientation would be important only if a coronary vein were being bypassed
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