What Is the Extensor Carpi Ulnaris?

Wrist joint is a complex joint composed of multiple joints, including radial wrist joint, intercarpal joint, and carpal metacarpal joint. All three joints are related to each other (except the carpal and palm joints of the thumb), which are collectively referred to as the wrist joint. In a narrow sense, the wrist joint refers to the joint between the lower end of the radius and the first row of wrist bones (except the pea bone), that is, the radial wrist joint; but from the perspective of function, the wrist joint should actually include the radial wrist joint, the intercarpal joint, and the ulnar distance. Lateral joints, which are uniform in movement, and the wrist joint is located deep in the carpal tunnel. The wrist joint is the main part to complete the function of the upper limbs, and it is easy to cause damage in daily life.

Wrist joint is a complex joint composed of multiple joints, including radial wrist joint, intercarpal joint, and carpal metacarpal joint. All three joints are related to each other (except the carpal and palm joints of the thumb), which are collectively referred to as the wrist joint. In a narrow sense, the wrist joint refers to the joint between the lower end of the radius and the first row of wrist bones (except the pea bone), that is, the radial wrist joint; but from the perspective of function, the wrist joint should actually include the radial wrist joint, the intercarpal joint, and the ulnar distance. Lateral joints, which are uniform in movement, and the wrist joint is located deep in the carpal tunnel. The wrist joint is the main part to complete the function of the upper limbs, and it is easy to cause damage in daily life.

Chinese name

s

Foreign name

wrist joint

nickname

Radial wrist joint

Foreign name

radiocarpal joint

Wrist joint anatomy and composition

The radial wrist joint is composed of the triangular cartilage disc of the distal radius, the distal ulna, and the scaphoid, moon, and triangular bones in the proximal row of carpal bones. The intercarpal joint is composed of the proximal and distal carpal bones. The carpal metacarpophalangeal joint is composed of the far row carpal bone and the second to fifth metacarpal base, and the thumb carpal metacarpal joint consisting of most of the horn bones and the first metacarpal bone is an independent joint. The distal end of the radius is enlarged and the styloid process of the radius is extended downward. The dorsal side of the ulna head protrudes downward into the ulnar styloid process. The radial styloid process of a normal person is 1 to 1.5 cm longer than the ulnar styloid process. The ulnar head is completely extra-articular structure with respect to the wrist bone, but the outer semi-annular articular surface and the radius form the distal ulnar radial joint, and its distal side is related to the joint disc-related segment. The articular disc (triangular cartilage disc) is located between the ulnar and radial bones and separates the ulna from the wrist joint. It is attached to the ulnar styloid process, the medial side of the radius and the wrist capsule. The role of maintaining the stability of the distal ulnar radial joint.

Wrist joint structure

Each carpal bone forms a concave, approximately arched cavity on the palm side, called a carpal tunnel. It is covered by the carpal palmar ligament, which contains the flexor tendon and median nerve passing through. The ulnar nerve passes from the superficial surface of the carpal tunnel. by. Under normal circumstances, the pressure in the carpal tunnel is not high, but any joint changes can cause nerve compression. The wrist flexor tendon is surrounded by a synovium-lined tendon sheath, and the extensor tendon is also surrounded by a tendon sheath.

The wrist capsule is attached to the edge of the wrist, with ligaments strengthening on all sides. The main wrist ligaments are: Carpal palmar ligament: The radial carpal palmar ligament is the strongest, starting from the radial styloid process and the distal anterior edge of the radius, and ending at the near-line wrist and skull. dorsal carpal ligament: It is not as strong as the carpal palmar ligament, mainly the dorsal radial ligament, starting from the dorsal margin of the distal radius and ending at the proximal carpal bone (mainly the triangular bone). Carpal radial collateral ligament: from the radial styloid process to the scaphoid tubercle and most horns. ulnar collateral ligament: from the ulnar styloid process to the triangular and bean bones. Carpal transverse ligament: from the scaphoid tubercle and most horn bones to the leg bones and hooks. Carpal bone ligament: There is a series of ligaments that are closely connected to the carpal bones, and there is blood supply to the carpal bone at the attachment point.

Function: The wrist joint mainly has flexion and extension functions, as well as radial deflection and ulnar deflection. The wrist and palm joints of the thumb are saddle-shaped joints with two axial surfaces, so they have the functions of flexion, extension, adduction, abduction, rotation and various activities. The far ulnar radial joint and the near ulnar radial joint perform the pronation and supination functions of the forearm together.

Wrist imaging structure

The far row of carpal bones shows that the far row of carpal bones are arranged along the dorsal side of the wrist, and they are concavely curved toward the palm side. There are 9 superficial and deep flexor tendons and long flexor hallucis tendons in the carpal tunnel, with the median nerve at the front. The carpal tunnel and most of the horns are in front of the thumb-to-palm and brachial abductor muscles, and the carpal tunnel is in front of the palmar fascia. The innermost side is the short abductor of the little finger and the little palm to the palm. There are also many extensor tendons on the back of the wrist.

The proximal metacarpal level is similar to the far row carpal level, showing that the 1st to 5th metacarpal bases are arranged in an arcuate order from the inside to the outside, and the carpal tunnel is the cross-section structure below.

Wrist- related diseases and treatment

1. Wrist dislocation is a rare joint injury, but any wrist bone can be dislocated under external force. Because of its complex anatomical structure, misdiagnosis and misdiagnosis often occur.

2. Classification: Type I, simple flexion of the wrist joint dislocation; Type 2, flexion of the wrist and intercarpal joint dislocation.

3. Injury mechanism: Dislocation of the carpal bone. Due to the difference in the direction of the external force and the position of the injured body, it can clinically cause dorsiflexion and flexion injuries.

4. Treatment method

4.1 Manipulation reduction: dislocation within 3 weeks under brachial plexus anesthesia, manipulative reduction with wrist flexion at 30 ° for 2 weeks, and wrist functional position fixation for 4 weeks. Patients with fractures were fixed with plaster for 8 to 10 weeks, and then changed to the neutral position for 2 to 6 weeks. Six patients in this group underwent manual reduction.

4.2 Surgical incision and reduction and internal fixation: The longitudinal S incision of the wrist and palm is surgically taken. After the skin and subcutaneous tissues are cut, the back of the wrist joint capsule is exposed. Cut the switch capsule to expose the radial wrist joint and the celestial wrist joint. See the far row of the carpal bones detached to the back side, revealing the lunar bones and skull bones. Fresh fractures can be directly reduced by manual operation. If the reduction is difficult, a reduction screw can be screwed in the vertical direction of the cephalic bone, and the fold is restored under traction. After reduction, it was fixed with micro cancellous bone screws or Kirschner wires, while repairing the radial volar joint capsule, radial scaphoid ligament, and radial scaphoid ligament. Old scars showed local scar adhesion and disordered carpal bone arrangement. Before reduction, sharp peel adhesion should be performed, and care should be taken not to damage the cartilage surface of the cartilage and blood flow around the scaphoid. The scaphoid fracture end was exposed after reduction and fixation, and the angle, rotation and displacement were corrected. The hardened bone of the scaphoid stump was scraped off, fixed with micro cancellous screws or Kirschner wires, and the radial styloid process was removed and removed. Implant the stump bone defect area. After surgery, the abdomen was externally fixed with the gypsum tray and the abduction of the thumb was performed, and the wrist was neutralized for 4 weeks (the scaphoid Kirschner wire fixation group was cast for 8 weeks). Strengthen functional exercise after removing plaster.

Type I dislocation injury is minor, and its ligament tear is limited to scratching the wrist. This type of dislocation has a good prognosis. Generally, it can be treated with closed reduction and plaster fixation for 6 weeks. Only surgery is performed when the fracture piece hinders the reduction or the osteotomoid process of the fracture needs to be anatomically aligned. Stable, you can consider the use of crossed steel needles to prevent recurrence of subluxation. Type 11 dislocation injuries involve scratching the wrist joint, middle wrist joint, and scaphoid ligament, etc., and it is difficult to close the reduction. The correct treatment should be through open reduction of the carpal palm and dorsal side incision. Firstly, the styloid process of the bone is flexed to stabilize the wrist, and then the boat and moon are fixed with steel needles to stabilize the middle wrist and repair all tears. And repair all the larger fractures. Even so, the prognosis is still not optimistic. If secondary surgery is needed due to poor results, the authors believe that wrist fixation is better than near-row carpal resection.