Trapezium (bone)

Trapezium (bone)

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The trapezium bone in the human hand.

The trapezium is a small bone located in the wrist of the human hand. It is one of the eight carpal bones, which form the wrist joint. The trapezium is situated on the radial side of the wrist, between the scaphoid and the first metacarpal bone.

Anatomy

The trapezium bone is roughly quadrilateral in shape, hence its name. It has four surfaces: superior, inferior, anterior, and posterior. The superior surface is smooth and articulates with the scaphoid bone, forming the scaphotrapezial joint. The inferior surface is rough and provides attachment for ligaments and muscles. The anterior surface is concave and forms part of the saddle-shaped joint with the first metacarpal bone. The posterior surface is rough and serves as an attachment site for ligaments.

The trapezium bone also has four borders: radial, ulnar, dorsal, and palmar. The radial border is convex and articulates with the first metacarpal bone. The ulnar border is concave and forms the joint with the trapezoid bone. The dorsal border is rough and provides attachment for ligaments. The palmar border is smooth and forms part of the joint with the first metacarpal bone.

Function

The trapezium bone plays a crucial role in the movement and stability of the wrist joint. It acts as a pivot point for the thumb, allowing for opposition and precision grip. The saddle-shaped joint between the trapezium and the first metacarpal bone enables a wide range of thumb movements, including flexion, extension, abduction, adduction, and opposition.

Clinical Significance

Injuries or conditions affecting the trapezium bone can lead to significant functional impairment of the hand. Some common conditions include:

- Trapezium fracture: Trapezium fractures usually occur due to direct trauma or repetitive stress. They can cause pain, swelling, and limited thumb movement. Treatment may involve immobilization, physical therapy, or in severe cases, surgical intervention.

- Osteoarthritis: Osteoarthritis can affect the trapezium joint, leading to pain, stiffness, and reduced grip strength. Conservative management options include pain medication, splinting, and hand exercises. In advanced cases, surgical procedures such as trapeziectomy may be necessary.

See Also

• Carpal bones
• Wrist joint
• Scaphoid bone
• First metacarpal bone
• Trapeziectomy