Nocturnal pain on the outside of the elbow

Introduction The interosseous dorsal nerve compression syndrome can cause lateral elbow pain, which is characterized by rest pain and nighttime pain.

Cause

Etiology

The lesions are located in some specific anatomical parts, bone-fiber tube, or inelastic muscle fiber edge, zygomatic arch and other critical points of the nerve channel, where the compressed nerve is difficult to avoid and buffer. The causes can be grouped into three categories:

1 intra-tube compression: ganglion cyst, neurofibromatosis, chronic chronic inflammation of the nerve.

2 External compression: osteophytes, bones and key injuries, ligament injuries.

3 systemic diseases: rheumatoid arthritis, mucous edema, obesity, diabetes, hyperthyroidism, Reynaud disease, pregnancy, etc. can be combined with nerve compression.

[pathological changes]

The causative factors of nerve compression lesions are neuro-ischemia and mechanical damage. Acute short-term compression can cause nerve ischemia, blocked axial flow of the axonal axis, hypoxia, and edema. Severe and persistent compression can cause demyelination of nerve fibers, even the distal axonal disintegration, Waller degeneration of myelin. During limb movement, nerve fibers in the stenotic channel undergo chronic inflammatory inflammation under mechanical stimulation and aggravate the vicious circle of edema-ischemia. However, the general pathological changes are in the Seddon functional paralysis stage and the Sunderland grade 5 classification of the first and second grades. Most are reversible damage.

an examination

Related inspection

Joint examination electromyogram

(1) Muscular atrophy: Patients diagnosed with posterior interosseous nerve compression often have atrophy of the forearm extensor muscle group.

(2) Local tenderness: tenderness is often limited to 2 to 4 cm below the iliac crest, which is the posterior interosseous nerve of the compression. The external epithelium may also have tenderness. A double-sided examination should be performed during the examination to compare the response of the same anatomical position on both sides to the compression. Because of the normal pressure of the place, it is also sore.

(3) Induced pain: The anti-resistance when the elbow is stretched can induce pain. Because the supinator muscle is stretched before pronation, and the anti-resistance is rotated, the contraction of the supinator muscle is aggravated by the contraction of the interosseous nerve, and the sacral margin of the short wrist is also strong in the forearm. Contraction strengthens the compression of the nerves. Stretching the elbow, wrist extension, resistance to the middle finger, can induce lateral elbow pain, this is the middle finger test. Mainly to induce strong contraction of the short wrist muscles at the base of the third metacarpal, and stimulate the dorsal nerve of the bone to cause pain in the lateral elbow.

(4) Drowning test: bending the wrist position, repeatedly rotating the forearm, like rubbing off the water on the hand, can also induce pain. It is actually pulling the supinator and the iliac crest, and compressing the posterior interosseous nerve.

(5) local mass: a small number of patients with muscle atrophy, can be placed in the Frohse bow to a cord-like mass, the block has tenderness.

(6) Extension of the thumb and extension of the thumb: In advanced patients, the thumb can not stretch, can not be lateral abduction, 2 to 5 finger can not extend.

Differential diagnosis

Severe pain in the elbow, tenderness and swelling: localized swelling, pain and tenderness of the clavicle fracture are more obvious.

Swelling and tenderness of the elbow: intercondylar fracture of the humerus, severe pain after trauma to the elbow joint, extensive tenderness, obvious swelling, and may be accompanied by subcutaneous congestion.

Elbow pain: external humeral epicondylitis, iliac crest nerve vascular bundle is embedded in the elbow can cause elbow pain.

Abdominal elbow swelling and dysfunction: half of the radial head fracture is also called Hahn-steinthal fracture, symptoms and signs: elbow lateral swelling, elbow flexion and extension dysfunction.

Elbow sprain: The elbow sprain is mostly under the action of external force, causing the elbow to have an abnormal range of motion, causing damage to the medial and lateral collateral ligaments of the elbow.

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