-
Systemic conditions: (may mimic ulnar entrapment syndrome at elbow)
-
Syringomyelia
-
Amyotrophic Lateral Sclerosis
- Entrapment of the ulnar nerve distally at the wrist (
Guyon's canal)
- Snapping Elbow Syndrome:
- syndrome which has yet to be fully described, in which patients note recurrent snapping along
the medial aspect of the elbow;
- may either be due to anomalous triceps muscle insertion or due to recurrent subluxation of
ulnar nerve (which occurs from a deficient cubital tunnel);
- Anatomic Lesions;
- C-spine: (see
clinical exam)
- compression of cervical roots can cause radiating paresthesias in the hand;
-
C-8 (C7-T1 disk) &
T1 root can best be distinguished from ulnar nerve by pattern of muscle weakness;
- the correct diagnosis is made by noting the function of muscles innervated by the
C-8 and T1
portions of the median nerve; (ie, the function of index and long
FDP,
FPL, and thenar muscles);
-
Spinal cord tumor
- Extramedulary spinal lesions
- neurofibroma
- meningioma
- lesions of the brachial plexus or
medial cord
- Thoracic Outlet:
- rarely,
brachial plexus is involved by metastatic tumor or by thoracic outlet syndrome.
- consider Pancoast Tumor;
- Elbow:
-
medial epicondylitis is an associated complication;
-
cubital tunnel syndrome
- potential causes of ulnar entrapment, in approx order of frequency, are as follows:
- cubital tunnel syndrome, external compression, previous frx & scarring, recurrent subluxation of nerve, & entrapment;
-
recurrent ulnar nerve subluxation:
- may occur in upto 16-20% of population;
- as the elbow flexes, the ulnar nerve may sublux anteriorly over the epicondyle;
- references:
- Recurrent ulnar nerve dislocations at the elbow.
HM Childress.
CORR. Vol 108, 1975. p 168-170.
- Ulnar nerve strains at the elbow.
EB Toby et al.
J. Hand Surg. Vol 23-A. 1998. p 992-997.
-
snapping ulnar nerve sydrome:
- snapping of the medial head of the triceps over the medial epicondyle may occur by itself
or may occur along with ulnar nerve subluxation;
- triceps snapping may occur as the elbow is flexed or as it is extended
from a flexed position;
- failure to recognize this syndrome intra-operatively, can lead to clinical failure of ulnar nerve transposition;
- Wrist:
-
ulnar nerve can be compressed at wrist rather than elbow by repeated trauma to palm (often
occupational) or by ganglion or tumor;
- numbness over dorsum of the hand may be seen in Cubital Tunnel Syndrome in contrast to compression within
Guyon's canal (where dorsal sensory numbness would not be expected;
- in addition, ulnar nerve compression at the wrist would not be expected to cause weakness of
the FCU, nor weakness of the little and ring FDP muscles;
Snapping of the medial head of the triceps and recurrent dislocation of the ulnar nerve.
Anatomical and dynamic factors.
RJ Spinner and RD Goldner.
JBJS Vol 80-A. No 2. Feb 1998. p 239.
