The human skeletal system provides the framework that supports the body, allows for movement, and protects internal organs. Bones provide a rigid internal structure, maintaining body shape and serving as muscle attachment points for motion. This system includes various types of bones, each structured to fulfill specific roles.
Identifying Carpal Bones
The carpal bones in the wrist are classified as short bones. These bones are roughly cube-like or irregular in shape. The wrist contains eight carpal bones. They are arranged into two rows: a proximal row closer to the forearm and a distal row closer to the hand.
The proximal row articulates with the radius bone of the forearm, forming the main wrist joint. The distal row connects with the metacarpal bones, the long bones of the hand. This arrangement of multiple small bones, rather than a single large one, is fundamental to the wrist’s complex capabilities.
How Carpal Bones Function
Their irregular, cube-like shapes and numerous articulations contribute to the wrist’s flexibility, strength, and extensive range of motion. Their multiple articular surfaces allow them to form movable joints with adjacent bones, facilitating a wide array of movements including flexion, extension, and rotation. This design enables intricate movements for daily tasks, from grasping to precise manipulations.
Carpal bones also distribute forces across the hand and forearm. When force is applied to the hand, such as during a fall, the carpal bones help to absorb and transmit this stress, protecting the hand and fingers. The stability provided by these tightly connected short bones forms a base for the hand, allowing for controlled and powerful actions.
Common Carpal Conditions
The complex structure and constant use of the carpal bones make them susceptible to various conditions. Fractures are common, with the scaphoid bone being the most frequently fractured carpal bone. These fractures often result from a fall onto an outstretched hand, and delayed diagnosis can lead to complications such as non-union or arthritis.
Dislocations can also occur, disrupting their normal alignment. These injuries result from high-energy trauma, causing pain and instability. Carpal tunnel syndrome involves the carpal bones forming the floor and sides of a narrow passageway in the wrist. Compression of the median nerve within this tunnel leads to symptoms like numbness and tingling in the hand.