Brachial Plexus Structures Flashcards
7 cards from real Anatomy Exam practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Brachial Plexus Structures flashcards as text
A 'waiter's tip' deformity results from injury to which brachial plexus component?
Answer: Upper trunk (C5–C6)
Upper trunk injury (Erb's palsy) causes the arm to hang in adduction, medial rotation, and forearm pronation — the waiter's tip position.
Injury to the posterior cord of the brachial plexus would spare which movement?
Answer: Elbow flexion
Elbow flexion (primarily musculocutaneous nerve) arises from the lateral cord, not the posterior cord.
The nerve to the subclavius arises from which part of the brachial plexus?
Answer: Upper trunk
The nerve to subclavius (C5–C6) branches from the upper trunk of the brachial plexus.
Which cord of the brachial plexus splits into the musculocutaneous nerve and the lateral root of the median nerve?
Answer: Lateral cord
The lateral cord divides into the musculocutaneous nerve and contributes the lateral root to the median nerve.
A crutch placed too high in the axilla compresses which nerve structure, typically injuring which nerve first?
Answer: Posterior cord / Radial nerve
Crutch palsy most often affects the radial nerve via compression of the posterior cord in the axilla.
C7 nerve root contributes most heavily to which terminal nerve of the brachial plexus?
Answer: Radial nerve
The radial nerve (C5–T1) receives its largest contribution from C7, which forms the middle trunk.
Which brachial plexus branch provides motor innervation to the coracobrachialis, biceps brachii, and brachialis?
Answer: Musculocutaneous nerve
The musculocutaneous nerve (C5–C7) from the lateral cord innervates all three anterior arm muscles.