USMLE Step 1 Questions and Answers Full Test Bank
with complete solution
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 CNs are responsible for the sensor and motor components of the light reflex? - ANSWER-CN II is
the sensory limb and CN III is the motor component through parasympathetic stimulation.
Arrange the following layers in the correct sequence through which a needle must pass in a lumbar
puncture. • Skin • Subarachnoid space • Interspinous ligament • Dura mater • Deep fascia • Epidural
space • Superficial fascia • Interlaminar space • Supraspinous ligament • Arachnoid mater - ANSWER-
During a lumbar puncture the needle passes through the interlaminar space in the midline of L3-L4,
with the tip of the iliac crest in the flexed position as the landmark. Order of puncture: 1. Skin 2.
Superficial fascia 3. Deep fascia 4. Supraspinous ligament 5. Interspinous ligament 6. Interlaminar
space 7. Epidural space 8. Dura mater 9. Arachnoid mater 10. Subarachnoid space. (They ask this in
some variation every year, so know it.)
What ocular ganglion is affected if the pupil on the affected side sluggishly responds to light with
normal accommodation? - ANSWER-Ciliary ganglion producing a tonic pupil
What is the name for the most prominent spinous process? - ANSWER-Vertebra prominens (C7 in 70%
of cases, C6 in 20%, T1 in 10%)
What muscles make up the rotator cuff? - ANSWER-SITS—Subscapularis, Infraspinatus, Teres minor,
Supraspinatus
What is the function of white rami communicantes? - ANSWER-They are preganglionic sympathetic
axons. They are white because they are myelinated.
What muscle or muscles are innervated by the following nerves? • Suprascapular nerve - ANSWER-
Supraspinatus and infraspinatus
What muscle or muscles are innervated by the following nerves? • Upper subscapularis nerve -
ANSWER-Subscapularis
What muscle or muscles are innervated by the following nerves? • Thoracodorsal nerve - ANSWER-
Latissimus dorsi
What muscle or muscles are innervated by the following nerves? • Long thoracic nerve - ANSWER-
Serratus anterior
What nerve is associated with the following functions? • Flex the wrist and digits, pronate the wrist
and the LOAF (Lumbricales, Opponens pollicis, Abductor pollicis brevis, Flexor pollicis brevis) muscles
of the hand - ANSWER-Median nerve
What nerve is associated with the following functions? • Flex the shoulder, flex the elbow, and
supinate the elbow - ANSWER-Musculocutaneous nerve
What nerve is associated with the following functions? • Innervation of the flexor carpi ulnaris, flexor
digiti profundus (pinky and ring fingers), and the intrinsic muscles of the hand - ANSWER-Ulnar nerve
What nerve is associated with the following functions? • Supinate the wrist, extend the wrist and
digits, extend the shoulder and elbow - ANSWER-Radial nerve
What abdominal muscle runs horizontally, contributes to the posterior rectus sheath, and contributes
to form the conjoint tendon? - ANSWER-Transverse abdominis
Which CNs act as the sensory and motor components of the gag reflex? - ANSWER-The sensory limb is
via CN IX, and the motor limb is from CN X.
Which kidney is lower? Why? - ANSWER-The right kidney is lower in the abdominal cavity because of
the amount of space the liver occupies.
with complete solution
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 CNs are responsible for the sensor and motor components of the light reflex? - ANSWER-CN II is
the sensory limb and CN III is the motor component through parasympathetic stimulation.
Arrange the following layers in the correct sequence through which a needle must pass in a lumbar
puncture. • Skin • Subarachnoid space • Interspinous ligament • Dura mater • Deep fascia • Epidural
space • Superficial fascia • Interlaminar space • Supraspinous ligament • Arachnoid mater - ANSWER-
During a lumbar puncture the needle passes through the interlaminar space in the midline of L3-L4,
with the tip of the iliac crest in the flexed position as the landmark. Order of puncture: 1. Skin 2.
Superficial fascia 3. Deep fascia 4. Supraspinous ligament 5. Interspinous ligament 6. Interlaminar
space 7. Epidural space 8. Dura mater 9. Arachnoid mater 10. Subarachnoid space. (They ask this in
some variation every year, so know it.)
What ocular ganglion is affected if the pupil on the affected side sluggishly responds to light with
normal accommodation? - ANSWER-Ciliary ganglion producing a tonic pupil
What is the name for the most prominent spinous process? - ANSWER-Vertebra prominens (C7 in 70%
of cases, C6 in 20%, T1 in 10%)
What muscles make up the rotator cuff? - ANSWER-SITS—Subscapularis, Infraspinatus, Teres minor,
Supraspinatus
What is the function of white rami communicantes? - ANSWER-They are preganglionic sympathetic
axons. They are white because they are myelinated.
What muscle or muscles are innervated by the following nerves? • Suprascapular nerve - ANSWER-
Supraspinatus and infraspinatus
What muscle or muscles are innervated by the following nerves? • Upper subscapularis nerve -
ANSWER-Subscapularis
What muscle or muscles are innervated by the following nerves? • Thoracodorsal nerve - ANSWER-
Latissimus dorsi
What muscle or muscles are innervated by the following nerves? • Long thoracic nerve - ANSWER-
Serratus anterior
What nerve is associated with the following functions? • Flex the wrist and digits, pronate the wrist
and the LOAF (Lumbricales, Opponens pollicis, Abductor pollicis brevis, Flexor pollicis brevis) muscles
of the hand - ANSWER-Median nerve
What nerve is associated with the following functions? • Flex the shoulder, flex the elbow, and
supinate the elbow - ANSWER-Musculocutaneous nerve
What nerve is associated with the following functions? • Innervation of the flexor carpi ulnaris, flexor
digiti profundus (pinky and ring fingers), and the intrinsic muscles of the hand - ANSWER-Ulnar nerve
What nerve is associated with the following functions? • Supinate the wrist, extend the wrist and
digits, extend the shoulder and elbow - ANSWER-Radial nerve
What abdominal muscle runs horizontally, contributes to the posterior rectus sheath, and contributes
to form the conjoint tendon? - ANSWER-Transverse abdominis
Which CNs act as the sensory and motor components of the gag reflex? - ANSWER-The sensory limb is
via CN IX, and the motor limb is from CN X.
Which kidney is lower? Why? - ANSWER-The right kidney is lower in the abdominal cavity because of
the amount of space the liver occupies.
