USMLE Step 1 questions with complete solutions
What gland is found in the muscular triangle of the neck? - ANSWER Thyroid gland
Is an afferent or efferent pupillary defect described as B/L pupillary constriction when
light is shined in the unaffected eye and B/L paradoxical dilation when light is shined in
the affected eye? - ANSWER Afferent pupillary defect (CN II lesion); in an efferent
pupillary defect (CN III), B/L constrict when light is shined in the unaffected eye and
consentual pupil constriction occurs when light is shined in the affected eye.
What is the name of the spinal cord passing within the subarachnoid space and forming
the spinal nerves that exit the lumbar and sacral foramina? - ANSWER Cauda equina
Name the laryngeal muscle described by the following: • Pulls the arytenoids cartilages
closer to the thyroid, relaxing the vocal ligaments and thereby decreasing the pitch -
ANSWER Thyroarytenoid muscles
Name the laryngeal muscle described by the following: • Tenses the vocal ligaments,
increasing the distance between the cartilages, thereby increasing the pitch - ANSWER
Cricothyroid muscles
Name the laryngeal muscle described by the following: • Adducts the vocal ligaments,
closes the air passageway during swallowing, and allows phonation - ANSWER Lateral
cricoarytenoid muscles
Name the laryngeal muscle described by the following: • Only muscle to abduct the
vocal cords - ANSWER Posterior cricoarytenoid muscles
Where does the parotid (Stensen's) duct enter the oral cavity? - ANSWER Opposite the
second upper molar tooth
From what aortic arch are the following structures derived? • Common and internal
carotid arteries - ANSWER Third aortic arch MS CARD is my mnemonic for the aortic
arch derivatives
From what aortic arch are the following structures derived? • Degenerates - ANSWER
Fifth MS CARD is my mnemonic for the aortic arch derivatives
From what aortic arch are the following structures derived? • Stapes artery - ANSWER
Second MS CARD is my mnemonic for the aortic arch derivatives
From what aortic arch are the following structures derived? • Maxillary artery - ANSWER
First MS CARD is my mnemonic for the aortic arch derivatives
,From what aortic arch are the following structures derived? • Arch of the aorta and right
subclavian artery - ANSWER Fourth MS CARD is my mnemonic for the aortic arch
derivatives
From what aortic arch are the following structures derived? • Right and left pulmonary
arteries and the ductus arteriosus - ANSWER Sixth MS CARD is my mnemonic for the
aortic arch derivatives
What abdominal muscle contributes to the anterior layer of the rectus sheath, forms the
inguinal ligament, and in men gives rise to the external spermatic fascia of the
spermatic cord? - ANSWER External abdominal oblique
Name the compartment of the lower extremity and the nerve based on its movements. •
Adduct the thigh and flex the hip - ANSWER Medial compartment of the thigh, obturator
nerve
Name the compartment of the lower extremity and the nerve based on its movements. •
Plantar flex the foot, flex the toes, and invert the foot - ANSWER Posterior compartment
of the leg, tibial nerve
Name the compartment of the lower extremity and the nerve based on its movements. •
Dorsiflex the foot, extend the toes, and invert the foot - ANSWER Anterior compartment
of the leg, deep peroneal nerve
Name the compartment of the lower extremity and the nerve based on its movements. •
Flex the hip and extend the knee - ANSWER Anterior compartment of the thigh, femoral
nerve
Name the compartment of the lower extremity and the nerve based on its movements. •
Extend the hip and flex the knee - ANSWER Posterior compartment of the thigh, tibial
nerve
Name the compartment of the lower extremity and the nerve based on its movements. •
Plantar flex the foot and evert the foot - ANSWER Lateral compartment of the leg,
superficial peroneal nerve
What are the five branches of the posterior cord of the brachial plexus? - ANSWER
STARS 1. Upper Subscapularis 2. Thoracodorsal 3. Axillary 4. Radial 5. Lower
Subscapularis
Name the correct artery. • The right recurrent laryngeal nerve passes around it. -
ANSWER Right brachiocephalic artery
Name the correct artery. • The left recurrent laryngeal nerve passes around it. -
ANSWER Arch of the aorta
,The inferior mesenteric artery drains into it. - ANSWER The splenic vein
Are the quadrate and caudate lobes of the liver functionally part of the left or right lobe?
- ANSWER Functionally they are part of the left lobe of the liver because they receive
their blood supply from the left hepatic artery. Anatomically they are considered part of
the right lobe of the liver.
What bones make up the acetabulum? - ANSWER Pubis, ilium, and ischium
What is the anatomic positioning of the right and left gastric nerve plexus of the
esophagus as they pass through the diaphragm? - ANSWER LARP: Left goes Anterior
and Right goes Posterior (because of the rotation of the gut; remember your
embryology!)
What vessel is lacerated in an epidural hematoma? - ANSWER Middle meningeal artery
True or false? Below the arcuate line, all the aponeurotic fibers run anterior to the rectus
abdominis. - ANSWER TRUE
What ocular muscle • Adducts the eyeball and is involved in horizontal conjugate gaze?
- ANSWER Medial rectus (CN III) (LR6 SO4)3
What ocular muscle • Elevates and adducts the eyeball? - ANSWER Superior rectus
(CN III) (LR6 SO4)3
What ocular muscle • Depresses and abducts the eyeball? - ANSWER Superior Oblique
(CN IV) (LR6 SO4)3
What ocular muscle • Elevates and abducts the eyeball? - ANSWER Inferior Oblique
(CN III) (LR6 SO4)3
What ocular muscle • Abducts the eyeball and is involved in horizontal conjugate gaze?
- ANSWER Lateral rectus (CN VI) (LR6 SO4)3
What ocular muscle • Depresses and adducts the eyeball? - ANSWER Inferior rectus
(CN III) (LR6 SO4)3
Which muscles of the eye are under parasympathetic control? - ANSWER Constrictor
pupillae and ciliary muscles
Which direction does the uvula deviate in a left vagus nerve lesion? - ANSWER A left
CN X lesion results in the uvula deviating to the right. (Uvula points away from the
affected side.)
Is a subdural hematoma an arterial or venous bleed? - ANSWER Subdural hematoma is
a rupture of the cerebral veins where they enter the superior sagittal sinus.
, Which CNs are found in the midline of the brainstem? - ANSWER CN I, II, III, VI, and XII
Add 1 + 1 = 2, 1 + 2 = 3, 1 + 2 + 3 = 6, 1 + 2 + 3 + 6 = 12
What muscles insert in or on the intertubercular groove of the humerus? - ANSWER
"Lady between two Majors": latissimus dorsi, pectoralis major, and teres major
What nerve supplies taste sensation to the anterior two-thirds of the tongue? -
ANSWER Chorda tympani of CN VII
What part of the heart forms • The right border? - ANSWER Right atrium
What part of the heart forms • Left border? - ANSWER Left ventricle and auricle of left
atrium
What part of the heart forms • Apex? - ANSWER Tip of the left ventricle
What part of the heart forms • Base? - ANSWER Left atrium and tip of the right atrium
What part of the heart forms • Superior border? - ANSWER Conus arteriosus of the right
ventricle and right and left auricles
What part of the heart forms • Anterior wall? - ANSWER Right ventricle
What part of the heart forms • Posterior wall? - ANSWER Left atrium
What part of the heart forms • Diaphragmatic wall? - ANSWER Left ventricle and tip of
right ventricle
What nerves carry the sensory and motor components of the blink reflex? - ANSWER
CN V1 carries the sensory and CN VII carries the motor component of the blink reflex.
What muscle keeps the stapes taut against the oval window? - ANSWER Stapedius
muscle
Name the components of the femoral canal, working laterally to medially. - ANSWER
NAVEL: Femoral Nerve, Artery, Vein, Empty space, and Lymphatics/Lacunar ligament
What muscle is most superior in the orbit? - ANSWER Levator palpebrae superioris
What portion of the pericardium adheres to the tunica adventitia of the great vessels? -
ANSWER Fibrous pericardium
What two veins form the portal vein? - ANSWER The superior mesenteric vein and the
splenic vein (after it receives the inferior mesenteric vein) join to form the portal vein.
What gland is found in the muscular triangle of the neck? - ANSWER Thyroid gland
Is an afferent or efferent pupillary defect described as B/L pupillary constriction when
light is shined in the unaffected eye and B/L paradoxical dilation when light is shined in
the affected eye? - ANSWER Afferent pupillary defect (CN II lesion); in an efferent
pupillary defect (CN III), B/L constrict when light is shined in the unaffected eye and
consentual pupil constriction occurs when light is shined in the affected eye.
What is the name of the spinal cord passing within the subarachnoid space and forming
the spinal nerves that exit the lumbar and sacral foramina? - ANSWER Cauda equina
Name the laryngeal muscle described by the following: • Pulls the arytenoids cartilages
closer to the thyroid, relaxing the vocal ligaments and thereby decreasing the pitch -
ANSWER Thyroarytenoid muscles
Name the laryngeal muscle described by the following: • Tenses the vocal ligaments,
increasing the distance between the cartilages, thereby increasing the pitch - ANSWER
Cricothyroid muscles
Name the laryngeal muscle described by the following: • Adducts the vocal ligaments,
closes the air passageway during swallowing, and allows phonation - ANSWER Lateral
cricoarytenoid muscles
Name the laryngeal muscle described by the following: • Only muscle to abduct the
vocal cords - ANSWER Posterior cricoarytenoid muscles
Where does the parotid (Stensen's) duct enter the oral cavity? - ANSWER Opposite the
second upper molar tooth
From what aortic arch are the following structures derived? • Common and internal
carotid arteries - ANSWER Third aortic arch MS CARD is my mnemonic for the aortic
arch derivatives
From what aortic arch are the following structures derived? • Degenerates - ANSWER
Fifth MS CARD is my mnemonic for the aortic arch derivatives
From what aortic arch are the following structures derived? • Stapes artery - ANSWER
Second MS CARD is my mnemonic for the aortic arch derivatives
From what aortic arch are the following structures derived? • Maxillary artery - ANSWER
First MS CARD is my mnemonic for the aortic arch derivatives
,From what aortic arch are the following structures derived? • Arch of the aorta and right
subclavian artery - ANSWER Fourth MS CARD is my mnemonic for the aortic arch
derivatives
From what aortic arch are the following structures derived? • Right and left pulmonary
arteries and the ductus arteriosus - ANSWER Sixth MS CARD is my mnemonic for the
aortic arch derivatives
What abdominal muscle contributes to the anterior layer of the rectus sheath, forms the
inguinal ligament, and in men gives rise to the external spermatic fascia of the
spermatic cord? - ANSWER External abdominal oblique
Name the compartment of the lower extremity and the nerve based on its movements. •
Adduct the thigh and flex the hip - ANSWER Medial compartment of the thigh, obturator
nerve
Name the compartment of the lower extremity and the nerve based on its movements. •
Plantar flex the foot, flex the toes, and invert the foot - ANSWER Posterior compartment
of the leg, tibial nerve
Name the compartment of the lower extremity and the nerve based on its movements. •
Dorsiflex the foot, extend the toes, and invert the foot - ANSWER Anterior compartment
of the leg, deep peroneal nerve
Name the compartment of the lower extremity and the nerve based on its movements. •
Flex the hip and extend the knee - ANSWER Anterior compartment of the thigh, femoral
nerve
Name the compartment of the lower extremity and the nerve based on its movements. •
Extend the hip and flex the knee - ANSWER Posterior compartment of the thigh, tibial
nerve
Name the compartment of the lower extremity and the nerve based on its movements. •
Plantar flex the foot and evert the foot - ANSWER Lateral compartment of the leg,
superficial peroneal nerve
What are the five branches of the posterior cord of the brachial plexus? - ANSWER
STARS 1. Upper Subscapularis 2. Thoracodorsal 3. Axillary 4. Radial 5. Lower
Subscapularis
Name the correct artery. • The right recurrent laryngeal nerve passes around it. -
ANSWER Right brachiocephalic artery
Name the correct artery. • The left recurrent laryngeal nerve passes around it. -
ANSWER Arch of the aorta
,The inferior mesenteric artery drains into it. - ANSWER The splenic vein
Are the quadrate and caudate lobes of the liver functionally part of the left or right lobe?
- ANSWER Functionally they are part of the left lobe of the liver because they receive
their blood supply from the left hepatic artery. Anatomically they are considered part of
the right lobe of the liver.
What bones make up the acetabulum? - ANSWER Pubis, ilium, and ischium
What is the anatomic positioning of the right and left gastric nerve plexus of the
esophagus as they pass through the diaphragm? - ANSWER LARP: Left goes Anterior
and Right goes Posterior (because of the rotation of the gut; remember your
embryology!)
What vessel is lacerated in an epidural hematoma? - ANSWER Middle meningeal artery
True or false? Below the arcuate line, all the aponeurotic fibers run anterior to the rectus
abdominis. - ANSWER TRUE
What ocular muscle • Adducts the eyeball and is involved in horizontal conjugate gaze?
- ANSWER Medial rectus (CN III) (LR6 SO4)3
What ocular muscle • Elevates and adducts the eyeball? - ANSWER Superior rectus
(CN III) (LR6 SO4)3
What ocular muscle • Depresses and abducts the eyeball? - ANSWER Superior Oblique
(CN IV) (LR6 SO4)3
What ocular muscle • Elevates and abducts the eyeball? - ANSWER Inferior Oblique
(CN III) (LR6 SO4)3
What ocular muscle • Abducts the eyeball and is involved in horizontal conjugate gaze?
- ANSWER Lateral rectus (CN VI) (LR6 SO4)3
What ocular muscle • Depresses and adducts the eyeball? - ANSWER Inferior rectus
(CN III) (LR6 SO4)3
Which muscles of the eye are under parasympathetic control? - ANSWER Constrictor
pupillae and ciliary muscles
Which direction does the uvula deviate in a left vagus nerve lesion? - ANSWER A left
CN X lesion results in the uvula deviating to the right. (Uvula points away from the
affected side.)
Is a subdural hematoma an arterial or venous bleed? - ANSWER Subdural hematoma is
a rupture of the cerebral veins where they enter the superior sagittal sinus.
, Which CNs are found in the midline of the brainstem? - ANSWER CN I, II, III, VI, and XII
Add 1 + 1 = 2, 1 + 2 = 3, 1 + 2 + 3 = 6, 1 + 2 + 3 + 6 = 12
What muscles insert in or on the intertubercular groove of the humerus? - ANSWER
"Lady between two Majors": latissimus dorsi, pectoralis major, and teres major
What nerve supplies taste sensation to the anterior two-thirds of the tongue? -
ANSWER Chorda tympani of CN VII
What part of the heart forms • The right border? - ANSWER Right atrium
What part of the heart forms • Left border? - ANSWER Left ventricle and auricle of left
atrium
What part of the heart forms • Apex? - ANSWER Tip of the left ventricle
What part of the heart forms • Base? - ANSWER Left atrium and tip of the right atrium
What part of the heart forms • Superior border? - ANSWER Conus arteriosus of the right
ventricle and right and left auricles
What part of the heart forms • Anterior wall? - ANSWER Right ventricle
What part of the heart forms • Posterior wall? - ANSWER Left atrium
What part of the heart forms • Diaphragmatic wall? - ANSWER Left ventricle and tip of
right ventricle
What nerves carry the sensory and motor components of the blink reflex? - ANSWER
CN V1 carries the sensory and CN VII carries the motor component of the blink reflex.
What muscle keeps the stapes taut against the oval window? - ANSWER Stapedius
muscle
Name the components of the femoral canal, working laterally to medially. - ANSWER
NAVEL: Femoral Nerve, Artery, Vein, Empty space, and Lymphatics/Lacunar ligament
What muscle is most superior in the orbit? - ANSWER Levator palpebrae superioris
What portion of the pericardium adheres to the tunica adventitia of the great vessels? -
ANSWER Fibrous pericardium
What two veins form the portal vein? - ANSWER The superior mesenteric vein and the
splenic vein (after it receives the inferior mesenteric vein) join to form the portal vein.
