Cubital

• Leaning on the elbow or prolonged elbow flexion during occupational activities (e.g., leaning on a desk), athletic activities, or surgical procedures (e.g., during general anesthesia)

• Blunt trauma

• Masses (e.g., tumors, hematomas)

• Metabolic abnormalities (e.g., diabetes)

Muscle weakness and atrophy

• Atrophy of the hypothenar muscles

  • Inability to flex the ring finger and little finger when asked to make a fist

  • Results in a hand position that is similar to the “OK sign” (proximal nerve lesions)

• Claw hand deformity (ulnar claw) [1]

  • Mainly in distal nerve injuries

  • Palsy of the 3rd and 4th lumbricals with preserved function of extrinsic flexors

  • Hyperextension at MCP joints and flexion at PIP and DIP joints of the ring finger and little finger

  • Present at rest, increases when the patient is asked to extend the fingers

• Wartenberg sign: little finger in persistent abduction due to weak third palmar interosseous muscle

• Froment sign: The thumb flexes at the interphalangeal joint while pinching a piece of paper to compensate for a weak adductor pollicis muscle.

• Jeanne sign

  • Caused by the loss of function of the adductor pollicis and the predominance of the extensor pollicis longus and the abductor pollicis brevis

  • Leads to hyperextension of the thumb's metacarpophalangeal joint

• Lesions at the elbow

  • Positive Tinel test: marked paresthesias can be reproduced in the ulnar portion of the hand by tapping on the medial epicondyle of the humerus.

  • Elbow lesions typically present with referred pain in the forearm.

• Lesions at the ulnar canal (located in the wrist)

  • The ulnar canal is divided into three zones

    • Zone I: proximal to the bifurcation of the ulnar nerve

      • Motor and sensory symptoms (i.e., sensory loss in the palmar surface of the small finger and medial aspect of the ring finger) possible

      • Sensory features similar to those caused by proximal lesions at the elbow

    • Zone II: lesions at the deep motor branch cause motor symptoms only

    • Zone III: lesions at the distal sensory branch cause sensory symptoms only

• Electrodiagnostic studies

  • Typically involves nerve conduction studies and EMG

  • Identifies the level of nerve compression

• Ultrasound and MRI: used to support the EMG findings and to detect possible causes of compression (e.g., space-occupying lesions)

• X-ray: Consider cervical spine, chest, elbow, and wrist films to rule out other possible causes of symptoms.

• Conservative therapy

  • Modify behavior (e.g., avoid prolonged resting on elbow, repeated flexion of elbow)

  • Bracing at night

  • Analgesia (e.g., NSAIDs)

• Surgical decompression: if clinical features are severe, persistent (i.e., lasting more than 6 to 12 weeks), or progressively worsen despite conservative therapy.