Wartenberg's sign ( Fig. 2b) is an involuntary abduction (abduction posture) of little finger when asked to hold fingers together, caused by unopposed action of extensor digitiminimi due to weakness of ulnar nerve innervated intrinsic hand muscles-in particular the palmar interossei muscle to the little finger. Inability to hold the paper with adducted thumb and flexion of thumb interphalangeal joint (IPJ) due to flexor pollicis longus recruitment signifies a positive test. It is elicited by asking the patient to grasp a paper between the ulnar border of thumb and radial border of index finger. 9 Froment's sign ( Fig. 2a ) tests the power of adductor pollicis and first dorsal interosseous. Motor involvement manifests as wasting of first dorsal interosseous and clawing of little and ring fingers which is suggestive of severe compression. Hypoesthesia in the ulnar nerve distribution and positiveTinel's test over the cubital tunnel are helpful in establishing the diagnosis. If left untreated, it can progress to weakness and complete loss of sensation distal to the site of compression. Patients initially present with sensory symptoms such as paresthesia, numbness and pain along the distribution of the nerve, predominantly in the little finger and ulnar border of the ring finger.
However, some surgeons advocate anterior transposition if nerve instability is noted intra-operatively. Ulnar nerve subluxation has been reported as a risk factor for nerve entrapment, but without any conclusive evidence. 5 Keeping the arm under the head during sleep with shoulder abducted and elbow acutely flexed, can decrease nerve conduction velocity and cause paresthesias in the ulnar nerve distribution in the hand. 4 Baseball pitchers, truck divers or office workers whose job involve repetitive or prolonged flexion of elbow, are more likely to develop ulnar neuropathy. 3 When the elbow is bent, tensile load on the nerve increases and pressure within the cubital tunnel can be as high as 20 times of that at rest. The ulnar nerve becomes taut in flexion and continues to be stretched as the area in the cubital tunnel decreases beyond 90° of flexion. Ulnar nerve can also be compressed by valgus deformity/olecranon bursitis or synovitis around medial epicondyle in patients of rheumatoid arthritis of elbow.Īmong these, the most common site of compression is between the two heads of FCU. Ulnar nerve entrapment sites around elbow.
We hereby provide an overview of nerve entrapments around the elbow including their applied anatomy, etiology, clinical assessment and overview of the current concepts in surgical treatment.
Ulnar nerve compression trial#
Management should involve a trial of conservative treatment and failing that, surgical treatment should be considered. Electrodiagnostic studies can be a useful adjunct to clinical examination, to help localize the site and quantify the grade of compression. Median and Radial nerve compression around the elbow, albeit less frequent, can also lead to significant morbidity and must be kept in the differential diagnosis when dealing with patients complaining of persistent pain around the elbow and weakness of forearm/hand muscles. Cubital tunnel syndrome leading to ulnar nerve compression can often present with significant pain, paresthesia or weakness. The major nerves that traverse the elbow are ulnar, median and radial nerves and their branches. Entrapment neuropathy around elbow is a common cause of disability across all age groups.
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