Investigations take the form of:

Imaging studies

Radiographs of the elbow and wrist are mandatory in ulnar nerve compression because entrapment of the ulnar nerve may occur at more than one level.

Radiographs of the elbow may reveal abnormal anatomy such as a valgus deformity, bone spurs or bone fragments, a shallow olecranon groove, osteochondromas and destructive lesions (for example tumours, infections and abnormal calcifications).

Radiographs of the wrist may reveal fractures of the hook of the hamate, dislocations of the wrist bones and, to a lesser extent, soft tissue masses and calcifications.

Magnetic resonance imaging (MRI) is not usually necessary unless delineation of soft tissue masses, or visualisation of swelling or other abnormalities in the nerve, is desired.

Diagnostic procedures

Electromyography tests and nerve conduction studies are indicated to confirm the area of entrapment, document the extent of the pathology and detect, or rule out, the possibility of double crush syndrome (compression of nerve in more than one place).

In addition, Tinel’s and Phalen’s tests can also be used:

Fig 1: Tinel’s test Fig 2: Phalens test