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Chapter 17: median neuropathy, Preston and Shapiro
Terms in this set (32)
in CTS there is little correlation between
clinical symptoms and the abnormalities seen on NCS/EMG
differentials of CTS
1. entrapment of proximal median nerve 2. brachial plexus,3. cervical nerve roots. 4. ulnar
the median nerve is formed by
the medial and lateral cords of the brachial plexus (C6-T1)
what muscles are supplied by the median nerve in the forearm
PT, FCR, FDS, and PL (some patient)
AIN innervates the
FPL, FDP (medial head), and PQ
AIN is considered
pure motor "officially"
what branches off just proximal to the wrist and carpal tunnel
PCS--supplies sensation over the thenar eminence
what forms the roof of the CT
transverse carpal ligament
what is the motor division of the median nerve in the palm
L1, L2 and recurrent thenar motor branch
what does the recurrent thenar motor branch supply?
OP, APB, and FPB
sensory fibers suppy
first 3.5 fingers.
what is not affected in CTS
what symptoms are first in CTS
sensory paresthesias, later motor
what is hypoesthesia
refers to a reduced sense of touch or sensation, or a partial loss of sensitivity to sensory stimuli. In everyday speech this is sometimes referred to as "numbness". Hypoesthesia is one of the negative sensory symptoms associated with cutaneous sensory disorder (CSD).
sensation over what area is spared and why?
thenar area bc of PCS, arises proximally to CT
what is more sensitive..phalen or tinnel
what is median nerve slowing at the wrist w/o symptoms
not CTS-common in polyneuropathy, not uncommon for patients with polyneuropathy to have slowing at entrapment sites w/o symptoms--diagnosis is median neuropathy at wrist superimposed on polyneuropathy w/o ED
most common etiology of CTS
what physiologic changes are seen
edema, vascular sclerosis, and fibrosis c/w repeated stress to connective tissue
compression leads to
ischemia and demyelination that if severe enough can lead to wallerian degeneration and axonal loss
other than idiopathic causes what are 5 common causes
diabetes, hypothyroid, RA, amyloidosis, and pregnancy
what is the most common d/o may be confused with CT
cervical radic, C6 or C7, tease it out with pain associated with neck
what are PE findings can help differentiate CT from Cervical radic
abnml reflexes, diminished power in proximal muscles, especially EF, EE, pronation and sensory abnormalities in the palm or forearm
brachial plexus lesions PE findings
sensory abnormalities in plam or foearm, weakness in forearm muscles (pronation, wrist flexion)
how does BP lesions differ from radics?
weakness or sensory loss is widespread, not in one spinal segmen
What conditions may present with transient paresthesias
focal seizures, migraines, TIAs, and in exceptoina caes some patients have been found to have small lacunar infartsinvolving the lateral thalamus and IC--
If there is either demylionation with conduction block or axonal loss the distal CMAP and SNAP ampl will
be decreased as well as the latencies.
what are the common median versus ulnar comparison tests
1. median-veruss ulnar wrist to digit 4 sensory latencies 2. median vs ulnar palm to wrist mixed nerve latencies 3)median (2nd lumbrical) vs ulnar (INT)distal motor latencies 4. median vs radial comparison
the diagnostic yield improves from a ___ to ___
75% to 95% with comparison studies.
what is measured in the palm to wrist
both cutaneous sensory and muscles sensory (Ia afferents, susceptible to demyelination
what is the distance of the palm to wrist
where are the electrodes placed
median at wrist bw 2nd and 3rd digits
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