ABEM Anatomy & Neurophysiology Flashcards
6 cards from real ABEM practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 ABEM Anatomy & Neurophysiology flashcards as text
In the neuromuscular junction, acetylcholine binds to receptors on which structure?
Answer: Postsynaptic muscle endplate
Acetylcholine released from the presynaptic terminal diffuses across the synaptic cleft and binds to nicotinic receptors on the postsynaptic muscle endplate.
The fibular (peroneal) nerve winds around which bony landmark, making it vulnerable to compression?
Answer: Fibular head
The common peroneal nerve wraps superficially around the fibular head, making it highly susceptible to external compression injury.
Which electrophysiologic parameter primarily reflects the number of functional axons in a nerve?
Answer: CMAP or SNAP amplitude
CMAP (compound muscle action potential) and SNAP (sensory nerve action potential) amplitudes reflect the number of conducting axons contributing to the response.
The C8 nerve root primarily contributes to sensation in which dermatome?
Answer: Ring and little fingers
The C8 dermatome covers the ring and little fingers and the medial hand, and C8 radiculopathy commonly causes sensory symptoms in this distribution.
Ephaptic transmission refers to:
Answer: Abnormal cross-talk between adjacent nerve fibers
Ephaptic transmission is abnormal electrical cross-talk between adjacent demyelinated nerve fibers, which can produce spontaneous or stimulus-evoked ectopic discharges.
Which muscle is innervated by the deep fibular (peroneal) nerve and tested to assess L4-L5 function?
Answer: Tibialis anterior
The tibialis anterior is innervated by the deep peroneal nerve and is the primary muscle tested for L4-L5 nerve root function on EMG.