Hand muscle atrophy

Introduction In the movement and sensory examination of the ulnar tube syndrome, the little finger and the ring finger sensation of the ulnar side of the palmar surface and the atrophy of the hand muscle. Compression of the fracture piece, nerve traction or scar compression can cause neuropathy. Ulnar artery embolization can cause sensory disturbance alone, and such factors account for 7% of the ruler syndrome. Tapered tube syndrome caused by repetitive trauma accounts for about 6% of the total number of patients.

Cause

(1) Causes of the disease

The most common cause of ulnar nerve compression is nodular compression. It has been reported in the literature that 29% to 34% of cases are caused by nodule compression. Among the cases without obvious trauma, 86% of patients were caused by nodular compression, and most of the nerve compression sites were located at the joints of the triangular bone and the hook bone. Muscle variability, such as the deformation of the little finger flexor, the small finger muscles and the extension of the palm length to the Gunyon tube, is also the main cause of the ulnar tube syndrome, accounting for about 16% of the total number of patients. Other factors, such as lipoma, giant cell tumor, ganglion cyst, ligament thickening, soy bone hook joint, etc., can also cause ulnar nerve compression.

The ruler syndrome caused by fracture is the main factor of compression. The ulnar side fracture, especially the hook bone fracture, can occur in about 14% of patients with ulnar nerve compression. Compression of the fracture piece, nerve traction or scar compression can cause neuropathy. Ulnar artery embolization can cause sensory disturbance alone, and such factors account for 7% of the ruler syndrome. Tapered tube syndrome caused by repetitive trauma accounts for about 6% of the total number of patients. Rheumatoid bursitis, especially the ulnar wrist flexor and the superficial flexor tendon bursitis, are also associated with the occurrence of ulnar tube syndrome.

(two) pathogenesis

The ulnar tube is also known as the Guyon tube. The entrance is a triangle consisting of the lateral surface of the pea ulnar side, the superficial ligament of the carp ligament and the posterior side of the transverse ligament of the wrist. At the bottom of the Guyon tube, the bean ligament is located in the center, the transverse ligament fiber is located on the temporal side, and the pea ligament is located on the ulnar side and distal end. The top is composed of the transverse ligament of the wrist, the fiber bundle at the proximal end of the palmar aponeurosis and the distal end of the palmar short muscle. The Guyon tube is divided into two pipes by the hook bone at the exit. The distal hole is composed of a fiber arch composed of the small finger muscle and the small finger flexor, and the pea bone is connected with the hook bone. The ulnar nerve movement is pierced from the deep part of the hole, and the sensory branch is worn out from the shallow side.

Shea and McClain divide the ruler into three zones. In zone 1, the nerve compression is located in the proximal or ulnar tube. Because the nerve movement and sensory branch are in this area, the clinical manifestations include the weakening or atrophy of the intramuscular muscles in the ulnar nerve innervation area, and the feeling of the palmar side and the ulnar side of the small fish. Variety. In zone 2, motor nerve compression occurs and the anatomical region is located between the exit of the ruler, the hook of the hookbone, the muscle of the little finger and the origin of the flexor of the little finger. The ulnar nerve is stuck when the movement branch passes through the little finger to the metacarpal muscle, or when the trans-shoulder reaches the flexor tendon and the metacarpal metacarpal. In zone 3, the sensation of the sensory branch occurs, and the anatomical position of the compression is located at the distal end of the ulnar tube outlet or within the ulnar tube. The clinical manifestations are sensory disturbances of the small fish and the ring finger and the little finger.

an examination

Related inspection

Electromyogram biceps reflex

1. History and clinical manifestations are often referred to as ring finger, small finger numbness, intramuscular muscle weakness for the patient's complaint, history of hand ulnar fall, long-term use of vibration tools, rheumatoid history, osteoarthritis and other medical history for reference value.

2. Physical inspection

(1) tenderness or mass in the wrist hook area: The most common cause of compression in the 1st and 2nd areas is the hook fracture of the hook bone. Therefore, such patients often have tenderness near the hook bone.

(2) Tinel sign: Tinel sign positive in the ulnar tube area has certain value for diagnosis.

(3) Exercise and sensation examination: the little finger and the ring finger side of the ulnar side of the palm face feel abnormal and the hand muscle atrophy.

According to medical history, clinical manifestations, physical examination, electromyography examination of muscle strength and sensory disturbance, X-ray examination can exclude fractures, MRI examination can exclude local space-occupying lesions, and then establish a diagnosis.

Differential diagnosis

Because the ulnar nerve back of the ulnar nerve is issued before entering the ulnar ulnar, the ulnar tube syndrome only shows a sensation of the palmar side of the ulnar side. If the sensation of the dorsal side of the finger is simultaneously decreased, the ulnar nerve is also affected. The compression should be on the elbow rather than the wrist. If the patient has a sensation of skin on the medial side of the forearm, indicating that the medial cutaneous nerve of the forearm is involved, the thoracic outlet syndrome may be greater.

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