Radiology, Vol 158, 119-123, Copyright © 1986 by Radiological Society of North America
The cubital tunnel in ulnar entrapment neuropathy
JN St. John and JC Palmaz
Anteroposterior radiographs of the fully flexed and slightly externally
rotated elbow were obtained in 122 cases of cubital tunnel syndrome (CUTS)
and in 33 normal elbows. Medial trochlear lip osteophytes were not found in
the studies of normal elbows but were noted in 20% of ulnar nerve
entrapment cases. Medial incongruity between the trochlea and the olecranon
greater than or equal to 5 mm was found in 29% of CUTS cases and in 6% of
normal elbows. The presence of posttraumatic elbow-joint deformities seen
on radiographs correlated significantly with the degree of clinical
involvement. Depth and area measurements of ulnar nerve compression,
performed using a line-art representation of the radiographs, showed a
significant (P less than .0001) correlation between decrease in the area of
the cubital tunnel and ulnar innervated muscle atrophy. These findings
confirm the importance in this syndrome of both osteoarthritis and
incongruity of the medial structures of the elbow joint.
