Elbow canal syndrome: Chronic injury at the elbow is one of the common sites and causes of the lesion. The pathogenesis is a lesion of injury to the ulnar nerve in the elbow. The main manifestations are: indentation, thinning, enlargement of its proximal end, congestion; adhesions of varying degrees; abnormal position of the ulnar nerve groove; slippage of the ulnar nerve; and neoplasia within the ulnar nerve. The symptoms were relieved by surgical relocation of the ulnar nerve to the front and back of the elbow, indicating that the cause of the ulnar nerve lesion behind the elbow was mainly long-term compression, strain and abrasion. The causes of these lesions are as follows: 1. Elbow valgus, increased carry angle, relative shortening of the ulnar nerve, when the elbow joint is flexed, the ulnar nerve is stretched, compressed and worn; 2. Ulnar nerve slippage In normal people about 2-16% of the ulnar nerve slippage exists, of which there are few symptomatic people. When flexing the elbow, the ulnar nerve leaves the ulnar nerve groove, or moves to the front of the elbow through the inner ankle, and then returns to the original place when extending the elbow. With such a long-term round trip, the ulnar nerve is constantly rubbed, stretched and compressed. 3.The ulnar nerve is compressed in the elbow canal The ulnar nerve is located in the elbow canal behind the elbow. The bottom of the canal is the medial ligament of the elbow joint, the outer part is the eccrine process, the inner part is the medial ankle, and the top is a tendon membrane. When the elbow joint is flexed, the medial ligament protrudes and the tendon membrane is stretched, resulting in narrowing of the canal lumen and easy compression of the ulnar nerve. There is often a fascia under the tendon membrane, thus making the ulnar nerve more susceptible to compression. In addition, any change in the anatomical relationship of the elbow or hyperplasia of the elbow canal structure can cause narrowing of the canal lumen and compression of the ulnar nerve. 4, deformed healing of elbow fracture Most common in childhood are humeral epicondylar fracture, medial condyle fracture, flexor head fracture, elbow dislocation, etc., all can be produced by deformed healing when exostosis or other deformities, resulting in chronic injury to the ulnar nerve. 5, new organisms in the elbow canal Rarely. For example, tendon sheath cysts, osteophytes, etc. 6.Other unknown reasons. Zheng Weihao, Department of Traumatology, Shenzhen Pingle Orthopaedic Hospital Symptoms and diagnosis: The main symptom of this disease is chronic incomplete ulnar nerve palsy. The typical manifestation of ulnar nerve paralysis is claw-shaped hand deformity, with the ring finger and little finger as the most important, the thumb is often in an abducted state, the fingers are restricted to separate and combine movements, and the little finger movements are lost. The sensory loss area is mainly on the ulnar side of the dorsum of the hand, the ulnar half of the small fissure, little finger and ring finger. The onset of the disease is slow, the duration of the disease is long, the symptoms are mild, and it is not easy to diagnose and manage early. In the ulnar nerve distribution area of the hand, there is numbness or decreased skin sensation, which is often the earliest symptom of the disease, followed by the disappearance of skin tingling, generally the skin sensory disorder at the end of the finger is more severe, the more proximal the lighter the sensory disorder, and the complete disappearance of skin sensation in the ulnar half of the hand is rare. Sometimes there is radiating pain in the ulnar half of the hand. The interosseous muscles and interosseous muscles may have different degrees of atrophy and paralysis, generally light, but in severe cases there may be ulnar claw shape, limited adduction and abduction, reduced paper clamping force and reduced grip strength. There may also be varying degrees of atrophy of the ulnar side of the forearm, but there is no significant abnormality in the function of the 4th and 5th finger deep flexors and ulnar carpal flexors. Anyone who has the following conditions should undergo ulnar nerve anterior transposition of the elbow and ulnar nerve decompression if necessary. After the diagnosis is clear, the symptoms can be relieved by surgically cutting the carpal ulnar nerve canal bean hook canal and the little finger to palmar canal longitudinally, and it is better to do the nerve decompression at the same time.