Anatomy USMLE Practice Questions
Gross anatomy, embryology, and clinical correlations.
5 free anatomy practice questions
Pick an answer and check it. After each question you get the same explanation StepGenie students see: the stem decoded clue by clue, the reasoning chain with its infographic, why every wrong option is wrong, and the trap the question was built around. Step 1 questions test mechanism; Step 2 CK questions ask for the next step.
A 42-year-old woman, gravida 5 para 5, presents with a 6-month history of intermittent involuntary urine loss that occurs with coughing, sneezing, and laughing. She denies urinary urgency, frequency, or dysuria. Pelvic examination shows normal external genitalia, vagina, and cervix. During Valsalva maneuver, urine leakage is observed. The physician recommends pelvic floor (Kegel) exercises. Which of the following muscles is primarily strengthened by these exercises?
Correct answer · D
Levator ani
Decoding the stem
Step-by-step reasoning
Step 1 of 5
Urine loss with coughing/sneezing/laughing indicates stress urinary incontinence, not urge or overflow.
Step 2 of 5
Stress incontinence in multiparous women typically results from pelvic floor weakness and loss of urethral support.
Step 3 of 5
The levator ani (pubococcygeus, puborectalis, iliococcygeus) forms the main pelvic floor supporting bladder, urethra, and pelvic organs.
Step 4 of 5
Weak levator ani → urethra/bladder neck descend with ↑ intra-abdominal pressure → sphincter can’t stay closed → leakage on Valsalva.
Step 5 of 5
Kegel exercises are designed to selectively strengthen the levator ani muscles, improving urethral support and reducing stress incontinence.
Why not the others?
A. Compressor urethrae
This option implies strengthening an accessory external urethral sphincter muscle in the deep perineal pouch, which aids continence, BUT Kegel exercises are classically aimed at the pelvic floor (levator ani), the main support for the urethra and pelvic organs in stress incontinence.
B. Internal urethral sphincter
This option implies targeting the smooth muscle sphincter at the bladder neck (sympathetic control), BUT voluntary Kegel exercises train skeletal muscle, not smooth muscle; the key structure is levator ani, not the internal sphincter.
C. Sphincter urethrae
This option implies focusing on the external urethral sphincter in the deep perineal pouch, which provides active closure, BUT the primary defect in postpartum stress incontinence is loss of pelvic floor support (levator ani) rather than isolated sphincter weakness.
E. Deep transverse perineal muscles
This option implies strengthening muscles that stabilize the perineal body and support pelvic viscera, BUT they are minor contributors compared with the levator ani, which is the main pelvic diaphragm muscle targeted by Kegel exercises for stress incontinence.
Exam trap
Students may associate “urinary incontinence” with urethral sphincters and pick sphincter urethrae, but the key buzzwords (multiparity + cough/sneeze leakage + Kegels) point to pelvic floor (levator ani) weakness, not primary sphincter dysfunction.
The bottom line
Stress urinary incontinence from pelvic floor weakness is treated with Kegel exercises, which primarily strengthen the levator ani muscle group supporting urethra and pelvic organs.
A 13-year-old boy is brought to the emergency department by his parents due to severe left groin pain that began 4 hours ago while he was playing basketball. Physical examination shows a swollen, tender, and high-riding left testis. The cremasteric reflex is absent on the affected side. Urology is consulted, and the patient is scheduled for emergent surgery. An abnormality in which of the following anatomical structures is most likely responsible for this patient’s condition?
Correct answer · E
Tunica vaginalis
Decoding the stem
Step-by-step reasoning
Step 1 of 6
Peripubertal boy with sudden, severe unilateral testicular/groin pain and high-riding testis strongly suggests testicular torsion.
Step 2 of 6
Absent cremasteric reflex is a key distinguishing feature of testicular torsion versus epididymitis or other scrotal pathology.
Step 3 of 6
In testicular torsion, the testis twists around the spermatic cord, cutting off venous (then arterial) blood flow → acute pain and swelling.
Step 4 of 6
This twisting occurs due to a congenital bell-clapper deformity, where the testis is inadequately fixed within the scrotum.
Step 5 of 6
In the bell-clapper deformity, the tunica vaginalis completely surrounds the testis and part of the spermatic cord, allowing abnormal rotation.
Step 6 of 6
Therefore, an abnormality in the tunica vaginalis is responsible for this patient’s torsion.
Why not the others?
A. Tunica albuginea
This option implies a defect in the dense fibrous capsule of the testis, which is involved in testicular rupture, not torsion. Torsion is due to abnormal fixation by the tunica vaginalis, and there is no mention of trauma causing rupture or hematocele.
B. Cremasteric muscle
This option implies a problem with the muscle that elevates the testis and mediates the cremasteric reflex. The reflex is absent here because the testis is twisted and ischemic, not because the muscle itself is abnormal. The underlying predisposition is the bell-clapper deformity of the tunica vaginalis.
C. Tunica vasculosa
This option implies a problem with the vascular connective tissue layer deep to the tunica albuginea, which would affect testicular perfusion directly. In torsion, the initial issue is mechanical twisting of the spermatic cord due to abnormal tunica vaginalis attachment, not an intrinsic defect of the tunica vasculosa.
D. Tunica dartos
This option implies a defect in the smooth muscle layer of the scrotal wall responsible for temperature regulation of the testes. Dartos abnormalities would not cause acute severe pain or a high-riding testis. The key pathology here is intra-scrotal testicular rotation due to tunica vaginalis malfixation.
Exam trap
Students may pick any ‘tunica’ structure by name recognition. The key is to link testicular torsion with the bell-clapper deformity, specifically involving the tunica vaginalis encasing the testis and cord, not the tunica albuginea or dartos.
The bottom line
Testicular torsion from a bell-clapper deformity due to abnormal tunica vaginalis attachment → sudden severe testicular pain, high-riding testis, absent cremasteric reflex.
A 55-year-old man presents to the clinic with a 2-month history of progressive difficulty swallowing solid foods. His wife reports that his voice has become hoarse during this time, which they initially attributed to a recent episode of influenza. He has a history of type 2 diabetes mellitus managed with metformin and reports multiple childhood illnesses due to limited medical care. Vital signs are within normal limits. Cardiac auscultation reveals an opening snap best heard at the cardiac apex. Transthoracic echocardiography demonstrates an enlarged cardiac chamber compressing the esophagus. Changes in which of the following structures are most likely responsible for this patient’s symptoms?
Correct answer · B
Left atrium
Decoding the stem
Step-by-step reasoning
Step 1 of 5
An opening snap at the apex indicates mitral stenosis, most often due to chronic rheumatic heart disease.
Step 2 of 5
Chronic mitral stenosis causes pressure overload of the left atrium, leading to left atrial enlargement.
Step 3 of 5
The left atrium lies directly anterior to the esophagus; when enlarged, it can compress the esophagus, causing dysphagia to solids.
Step 4 of 5
The enlarged left atrium can also stretch/compress the left recurrent laryngeal nerve in the aortopulmonary window, causing hoarseness (Ortner syndrome).
Step 5 of 5
Thus, the patient’s dysphagia and hoarseness are best explained by left atrial enlargement secondary to mitral stenosis.
Why not the others?
A. Left ventricle
This option implies left ventricular hypertrophy/dilation, which causes heart failure or arrhythmias, BUT the LV does not lie directly against the esophagus and would not typically cause dysphagia/hoarseness from compression.
C. Right atrium
This option implies right atrial enlargement, which may be seen in pulmonary hypertension or tricuspid disease, BUT the right atrium is anterior and does not compress the posteriorly located esophagus.
D. Right ventricle
This option implies right ventricular hypertrophy/dilation, often from pulmonary hypertension, BUT the right ventricle is anterior and would not compress the esophagus or cause recurrent laryngeal nerve palsy.
E. Patent ductus arteriosus
This option implies a PDA, which can cause a continuous murmur and pulmonary overcirculation, BUT it is not described on exam/echo and classically does not present with isolated dysphagia and hoarseness from esophageal compression in adults.
Exam trap
Students may focus only on the valve (mitral stenosis) and forget the 3D cardiac anatomy: the left atrium sits directly anterior to the esophagus and can compress it when enlarged.
The bottom line
Left atrial enlargement from mitral stenosis compresses the esophagus and recurrent laryngeal nerve, causing dysphagia and hoarseness (Ortner syndrome).
A 51-year-old woman comes to the physician with progressively worsening low back pain that radiates down the posterior aspect of the right leg to the lateral side of the foot. She denies trauma, urinary incontinence, and fever. MRI of the lumbar spine shows disc degeneration and herniation at the L5–S1 level. Which of the following is the most likely finding on physical examination?
Correct answer · D
Weak achilles tendon reflex
Decoding the stem
Step-by-step reasoning
Step 1 of 5
Pain radiating from low back down the posterior leg to lateral foot localizes to the S1 dermatome → think S1 radiculopathy.
Step 2 of 5
MRI confirms L5–S1 disc herniation, which typically compresses the S1 nerve root.
Step 3 of 5
S1 nerve root supplies plantarflexors (gastrocnemius/soleus) and mediates the Achilles tendon reflex.
Step 4 of 5
Damage/compression of S1 → weakness of plantarflexion and decreased/absent Achilles reflex.
Step 5 of 5
Therefore, the most likely physical exam finding is a weak Achilles tendon reflex on the affected (right) side.
Why not the others?
A. Difficulty walking on heels
This option implies L5 radiculopathy (dorsiflexion weakness: heel walking), BUT this patient’s pain distribution (posterior leg, lateral foot) and L5–S1 herniation point to S1, not L5.
B. Exaggerated patellar tendon reflex
This option implies hyperreflexic L4 involvement or UMN lesion, which would cause brisk knee jerk, BUT radiculopathy from a lumbar disc herniation causes decreased, not increased, reflexes, and involves S1 here, not L4.
C. Diminished sensation of the anus and genitalia
This option implies saddle anesthesia from cauda equina syndrome, which would usually have urinary symptoms or severe neurologic deficits, BUT she denies urinary incontinence and has a focal S1 pattern instead.
E. Diminished sensation of the anterior lateral thigh
This option implies L2–L3 (or lateral femoral cutaneous nerve) involvement, BUT her sensory symptoms localize to posterior leg/lateral foot (S1), not anterior lateral thigh.
Exam trap
Students may focus only on the disc level L5–S1 and confuse L5 vs S1 findings. Always map pain distribution → dermatome → root → reflex/motor deficit explicitly.
The bottom line
S1 radiculopathy from L5–S1 disc herniation causes posterior leg/lateral foot pain with weak Achilles reflex and impaired plantarflexion.
A 56-year-old man is brought to the emergency department 30 minutes after falling from a height of 3 feet onto a sharp metal fence pole. He is unconscious on arrival. Physical examination reveals a 3-cm-deep penetrating wound located along the upper border of the right clavicle in the parasternal line. Which of the following is the most likely consequence of this injury?
Correct answer · B
Pneumothorax due to pleural injury
Decoding the stem
Step-by-step reasoning
Step 1 of 5
Upper border of clavicle in the parasternal line corresponds to the thoracic inlet region, just above the 1st rib and lung apex.
Step 2 of 5
The cervical pleura (cupola) and apex of the right lung project above the clavicle into the root of the neck.
Step 3 of 5
A 3‑cm‑deep penetrating wound here can lacerate the cervical/parietal pleura and underlying lung tissue.
Step 4 of 5
Air from the lung escapes into the pleural cavity when pleura is breached, causing loss of negative intrapleural pressure.
Step 5 of 5
Loss of negative pressure leads to lung collapse on the affected side → pneumothorax due to pleural injury.
Why not the others?
A. Rotator cuff tear due to supraspinatus muscle injury
This option implies shoulder region/greater tubercle trauma, which causes painful abduction, BUT the wound is parasternal at clavicle, not over the lateral shoulder where supraspinatus runs.
C. Trapezius muscle paresis due to spinal accessory nerve injury
This option implies injury to CN XI in the posterior triangle of the neck, causing shoulder droop, BUT the wound is anterior parasternal, not posterolateral neck where the nerve is superficial.
D. Hemathorax due to azygos vein injury
This option implies damage near the right posterior mediastinum/vertebral column where the azygos runs, BUT the described injury is anterior and high, not deep posterior where the azygos vein lies.
E. Chylothorax due to thoracic duct injury
This option implies injury to the thoracic duct, which ascends on the left side at the thoracic inlet, BUT the wound is on the right parasternal area, away from the duct’s typical location.
F. Traumatic aneurysm due to internal carotid artery injury
This option implies injury within the carotid sheath higher in the neck or skull base, causing neurologic/vascular signs, BUT the wound is over the clavicle/parasternal line, not along the carotid course.
Exam trap
The stem tempts you to think about generic chest trauma (hemothorax, great vessels). The key is precise surface anatomy: wound just above the clavicle in the parasternal line overlies the lung apex and cervical pleura, not the azygos vein, thoracic duct, or carotid artery.
The bottom line
Pneumothorax from parietal pleura puncture: penetrating trauma just above clavicle/1st rib can enter lung apex and cause collapsed lung with air in pleural space.
Source: StepGenie question bank. Questions are written by StepGenie, not taken from NBME or USMLE materials, and are chosen for this page by how students actually performed on them (first-attempt accuracy on StepGenie). Selection last refreshed September 5, 2026.
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Complete anatomical review including regional anatomy, embryological development, and clinical anatomy correlations. Master anatomical relationships essential for surgical and clinical reasoning.
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Anatomy — Frequently Asked Questions
How should you study anatomy for Step 1?
Study it clinically rather than exhaustively. The exam tests anatomy through injury and lesion questions, so prioritise structures with predictable deficits: brachial plexus and peripheral nerve injuries, rotator cuff, carpal tunnel, the inguinal region and hernias, and the vascular territories of the brain. Learn what a lesion looks like, not every named structure.
Which nerve injuries are most commonly tested?
Radial nerve injury from a midshaft humerus fracture causing wrist drop, axillary nerve injury from surgical neck fracture or shoulder dislocation, median nerve compression in the carpal tunnel, ulnar nerve injury at the medial epicondyle or hook of hamate, and common peroneal nerve injury at the fibular neck causing foot drop.
Why does embryology appear in anatomy questions?
Because congenital malformations are explained by which embryological process failed. Knowing that the pharyngeal arches give rise to specific nerves and muscles, or that failure of neural tube closure produces a spectrum of defects, lets you reason to an answer rather than recall it. Embryology also explains adult structures such as ligamentum arteriosum and urachal remnants.
How do you tell a direct from an indirect inguinal hernia?
An indirect hernia passes through the deep inguinal ring lateral to the inferior epigastric vessels, follows the inguinal canal, may reach the scrotum, and results from a patent processus vaginalis, making it the common type in infants. A direct hernia pushes through the weak Hesselbach triangle medial to those vessels and is acquired, typically in older adults.
Are the anatomy practice questions on this page free?
Yes. The 5 questions above come from StepGenie's question bank and can be answered here without an account, with the full explanation shown after each one. From the link under the set you can try three more Anatomy questions in the dashboard preview, also without an account; a free account is what lets you choose the system and keep going.