Cranial Nerves
An inability to abduct the eye laterally indicates a palsy of this specific cranial nerve.
What is CN VI (Abducens nerve)?
If a patient presents with a resting posture of a "claw hand" (hyperextension at the MCP joints and flexion at the IP joints of digits 4 and 5), they have lost the function of these intrinsic hand muscles.
What are the lumbricals (specifically the medial two lumbricals)?
Dr. Lei points to the deltoid tuberosity on a humerus. To get full credit, you must name the muscle that has its distal attachment here, its primary nerve, and its nerve roots.
What are the deltoid muscle, axillary nerve, and C5–C6?
The anterior divisions of the superior and middle trunks unite to form this cord.
What is the lateral cord?
A patient suffers from an arteriovenous malformation in the right occipital lobe, which function will MOST likely be compromised
What is Vision?
This cranial nerve innervates the superior oblique muscle, and its injury causes vertical diplopia that worsens when looking down and in (such as walking down stairs).
What is CN IV (Trochlear nerve)?
A displaced fracture of the olecranon process of the ulna will result in an absolute inability to actively extend the elbow joint due to the loss of this muscle's attachment.
What is the triceps brachii?
Dr. Lei taps the lesser tubercle of the humerus. You must identify the muscle making its distal attachment here, its specific upper/lower subscapular innervation, and its nerve roots.
What are the subscapularis, subscapular nerves, and C5–C6?
Arising from the root level (C4-C5), this nerve innervates the levator scapulae and both rhomboid muscles.
What is the dorsal scapular nerve?
These two major muscles of the posterior abdominal wall pass beneath the medial and lateral arcuate ligaments of the diaphragm, respectively.
What are the Psoas major and Quadratus lumborum?
A complete lesion of this nerve causes complete ptosis, a "down and out" eye position, and a fixed, dilated pupil.
What is CN III (Oculomotor nerve)?
Penetrating trauma to the mid-shaft of the humerus threatens the radial nerve within its groove, requiring you to screen this muscle to rule out an impending complete wrist drop.
What is the extensor carpi radialis longus (or brachioradialis)?
Dr. Lei points to the infraglenoid tubercle of the scapula. He asks the proximal attachment of a certain bifurcated muscle, and then list its nerve and roots.
What are the triceps brachii, radial nerve, and C6–C8?
During an upper extremity screen, a therapist notes shoulder internal rotation weakness and inability to initiate the first 15° of glenohumeral abduction. Damage to nerves arising from this single trunk accounts for these deficits.
What is the superior trunk (suprascapular nerve supplying supraspinatus/infraspinatus & nerve to subclavius)?
A patient presenting with their chin rotated down and to the left is suffering from a spasm of this specific muscle.
What is the right sternocleidomastoid?
When a patient is asked to protrude their tongue, it strays to the right side. This indicates a lower motor neuron lesion on this right side of the brain due to this nerve.
What is CN XII (hypoglossal)
A dominant-hemisphere stroke in the territory of this artery classicially presents with aphasia, contralateral hemiplegia, and sensory loss affecting the upper extremity and face more than the leg
What is the Middle Cerebral Artery (MCA)?
Dr. Lei holds your hand and finds the pisiform bone and the hook of the hamate. You must state the muscle that makes its distal attachment here, its motor nerve, and its exact spinal cord root origins.
What are the flexor carpi ulnaris (FCU), ulnar nerve, and C8–T1?
A patient following a MVA presents with the arm hanging extended at the side, internally rotated, and forearm pronated ("waiter's tip" posture). This clinical picture signifies an isolated traction injury to these two spinal roots.
What are C5-C6?
A patient with contralateral lower limb weakness and urinary incontinence likely has damage to this specific cerebral artery.
What is the anterior cerebral artery (ACA)?
Loss of taste on the posterior one-third of the tongue, along with an absent gag reflex sensory response, signals damage to this nerve.
What is CN IX (Glossopharyngeal nerve)?
An impacted fracture at the surgical neck of the humerus poses a high risk of injury to this nerve, leading to deltoid paralysis and loss of sensation over the lateral shoulder.
What is the axillary nerve?
Dr. Lei decides to ask you one last time about the medial lip of the intertubercular sulcus. You must name the muscle making its distal attachment here, its specific subscapular nerve branch, and its nerve roots.
What are the teres major, lower subscapular nerve, and C5–C6?
A cyclist complains of weakness during thumb adduction and numbness over the hypothenar eminence after long rides. Compression of the ulnar nerve is occurring within this specific wrist boundary.
What is Guyon's canal (or the ulnar tunnel)?
A patient suffers from acoustic schwannoma with the nerves coursing through the internal acoustic meatus severely impinged. Functions of this muscle will most likely be impaired.
Digastric (posterior belly)