Peripheral Nerves

  >  Ulnar Nerve
 Ulnar nerve

The ulnar nerve is a mixed nerve (motor and sensory). The motor and sensory parts of the nerve innervate the ring and little finger. It runs it through the ulnar canal  formed between the olecranon and medial epicondyle. At this point it is protected and supported by a powerful ligament.

The nerve can be entrapped as it runs through the canal by:

  • thickening of the ligament
  • Bone deformity due to sprain or old fracture
  • tumors of the same nerve
  • synovial cyst pushing the nerve
  • Injury to the nerve itself


Symptoms:

Patients whose ulnar nerve is pressured during its path display:

  • Abnormal sensations and paresthesias and/or sensory loss of the ring finger and little finger
  • Inability  to stretch the ring finger and little finger
  • Difficulty to grasp objects and antithetical  movement of the thumb and index fingers

Diagnosis:

The clinical diagnosis is given by the symptoms already described. Usually patients are unable to hold a sheet of paper between thumb and forefinger.

Additionally, electromyography is indicative of the transfer of information from nerves to muscles and locates the exact point of nerve compression and severity of the condition.

To assist, evaluation of simple  x-rays of the elbow joint (in the case of bone deformation ), CT and MRI of the same joint in order to identify the pathological conditions affecting the nerve may be needed.

Treatment:

Conservative treatment is limited and  applied only in cases of nerve injury. If the symptoms persist beyond three months and the electromyography reveals deterioration, surgical nerve decompression is the only permanent solution. Tendon transfer surgery is necessary in cases of paralysis of the finger tips.

Depending on the cause, incising the ligament, resection of bone deformation which is pressing the nerve, removal of cysts and/or tumors of the nerve may be required.

Transfer of the ulnar nerve is chosen in cases where the nerve is easily dislocated and trapped in front of the medial epicondyle.