Humeroulnar joint

A pivotal joint that allows movement of the arm and elbow.

The humeroulnar joint is a synovial hinge joint formed between the distal end of the humerus and the proximal end of the ulna. It plays a critical role in enabling flexion and extension of the forearm relative to the upper arm. This joint is one of the main articulations of the elbow, characterized by its structural stability and essential contribution to upper limb mobility.

Terminologia Anatomica

articulatio humeroulnaris

System

Musculoskeletal system

Function

The primary function of the humeroulnar joint is to facilitate the bending and straightening of the elbow, allowing for various movements critical to everyday activities. This joint's hinge-like structure enables a wide range of movements, particularly flexion, which involves bringing the forearm closer to the upper arm, and extension, which straightens the arm. These actions are pivotal for tasks such as lifting, throwing, and pushing, where precise control and movement of the arm are necessary. Furthermore, the humeroulnar joint also contributes to the functional biomechanics of the arm during complex activities that involve combined motions of the shoulder and forearm.

Location

The humeroulnar joint is located in the elbow region, specifically where the upper arm meets the forearm. It is formed by the larger bone of the upper arm, the humerus, and the inner bone of the forearm, the ulna. The joint is situated posteriorly to the bicep muscles and is protected superficially by the overlying skin and fascia, while deeper structures include ligaments and tendons that stabilize the joint during movement. Its proximity to the radius, another bone of the forearm, enables an intricate coordination of movements in the elbow joint area, contributing to the overall dexterity of the arm.

Did You Know?

The humeroulnar joint is responsible for about 140 degrees of flexion and 0 degrees of extension.
The ligaments surrounding the joint, such as the ulnar collateral ligament, play a crucial role in preventing dislocation during strenuous activities.
The unique structure of the joint allows it to withstand significant forces, making it vital for athletes who engage in throwing sports.