Lunate

A crescent-shaped bone located in the wrist that plays a critical role in wrist movement and stability.

The lunate is one of the eight carpal bones of the wrist, shaped like a crescent moon, hence its name. It is located in the proximal row of carpal bones, situated between the scaphoid and the triquetral bones. This bone connects the wrist to the forearm and is considered key in facilitating various wrist movements.

Terminologia Anatomica

os lunatum

System

Skeletal system

Function

The lunate bone is crucial for the intricate motions of the wrist, allowing for a wide range of motion including flexion, extension, and some degree of rotation. Its concave surface articulates with the distal end of the radius, contributing to the stability and functionality of the wrist joint. This bone not only serves as a crucial pivot point in wrist movement but also helps in transferring the load from the forearm to the wrist. Damage or misalignment of the lunate can significantly affect hand and wrist functionality, emphasizing its critical role in daily activities such as gripping and lifting.

Location

The lunate is situated within the wrist, found in the proximal row of carpal bones. It lies between the scaphoid bone on the lateral side and the triquetral bone on the medial side. Anteriorly, the lunate articulates with the capitate bone and is also involved in the articular surface where it meets the radius of the forearm. This positioning allows it to play a pivotal role in connecting the forearm to the hand.

Did You Know?

The lunate is prone to a condition called avascular necrosis, where the bone loses its blood supply, potentially leading to collapse.
In some studies, the lunate has been shown to be a key player in the diagnosis of various wrist injuries.
The shape of the lunate not only resembles a crescent moon but also hints at its functional significance in movement.
Variations in the shape and size of the lunate can affect how the wrist operates in different individuals.