Carpel

Carpal

The term "carpal" refers to the anatomical region of the wrist, which is composed of eight small bones known as the carpal bones. These bones form the connection between the forearm and the hand, playing a crucial role in the complex movements and functions of the wrist and hand.

Anatomy of the Carpal Bones

The carpal bones are arranged in two rows:

Proximal Row

• Scaphoid: Located near the base of the thumb, the scaphoid is the largest bone in the proximal row and is crucial for wrist stability.
• Lunate: Situated in the center of the proximal row, the lunate is crescent-shaped and articulates with the radius.
• Triquetrum: Positioned on the ulnar side of the wrist, the triquetrum is pyramid-shaped.
• Pisiform: A small, pea-shaped bone that sits on top of the triquetrum, the pisiform is a sesamoid bone within the tendon of the flexor carpi ulnaris.

Distal Row

• Trapezium: Located at the base of the thumb, the trapezium is important for thumb movement.
• Trapezoid: A small bone that articulates with the second metacarpal.
• Capitate: The largest carpal bone, located in the center of the wrist.
• Hamate: Recognizable by its hook-like projection, the hamate is located on the ulnar side of the distal row.

Function

The carpal bones form the carpal tunnel, a passageway for the median nerve and tendons that control finger movement. The arrangement of the carpal bones allows for a wide range of motion, including flexion, extension, abduction, and adduction of the wrist.

Clinical Significance

Carpal Tunnel Syndrome

Carpal tunnel syndrome is a common condition caused by compression of the median nerve as it passes through the carpal tunnel. Symptoms include numbness, tingling, and weakness in the hand.

Fractures

The scaphoid is the most commonly fractured carpal bone, often due to falls on an outstretched hand. Scaphoid fractures can lead to complications such as avascular necrosis due to its limited blood supply.

Arthritis

Osteoarthritis and rheumatoid arthritis can affect the carpal bones, leading to pain and reduced mobility.

See Also

• Wrist joint
• Hand anatomy
• Orthopedic surgery

References

• Gray's Anatomy: The Anatomical Basis of Clinical Practice.
• Netter's Atlas of Human Anatomy.