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Cross-section of shoulder joint. The shoulder joint is a ball-and-socket joint between the scapula and the humerus. The socket of the glenoid fossa of the scapula is itself quite shallow, but it is made deeper by the addition of the glenoid labrum. The glenoid labrum is a ring of cartilaginous fibre attached to the circumference of the cavity.
Joint From To Description Humeroulnar joint: trochlear notch of the ulna: trochlea of humerus: Is a simple hinge-joint, and allows of movements of flexion and extension only. Humeroradial joint: head of the radius: capitulum of the humerus: Is a ball-and-socket joint. Superior radioulnar joint: head of the radius: radial notch of the ulna
The shoulder joint is the main joint of the shoulder. It is a ball and socket joint that allows the arm to rotate in a circular fashion or to hinge out and up away from the body. The joint capsule is a soft tissue envelope that encircles the glenohumeral joint and attaches to the scapula , humerus , and head of the biceps .
As a whole the action is to adduct and medially rotate the humerus. It also draws the scapula anteriorly and inferiorly. The pectoralis major has four actions which are primarily responsible for movement of the shoulder joint. [7] The first action is flexion of the humerus, as in throwing a ball underhand, and in lifting a child.
The large muscles acting at this joint perform multiple actions and seemingly simple movements are often the result of composite antagonist and protagonist actions from several muscles. For example, pectoralis major is the most important arm flexor and latissimus dorsi the most important extensor at the glenohumeral joint, but, acting together ...
Muscles which flex the elbow joint such as the biceps brachii muscle, brachialis muscles and brachioradialis muscle are active to improve leverage. [1] As the biceps originate on the scapula unlike the other two which originate on the humerus, the biceps are inclined to serve a role as a dynamic stabilizer, much as the hamstrings would during a ...
The shoulder joint also known as the glenohumeral joint is a synovial ball and socket joint. The shoulder joint involves articulation between the glenoid cavity of the scapula (shoulder blade) and the head of the upper arm bone and functions as a diarthrosis and multiaxial joint. Due to the very loose joint capsule that gives a limited ...
The subscapularis stabilises the shoulder joint by contributing to the fixation of the proximal humerus during movements of the elbow, wrist, and hand. [1] It is a powerful defense to the front of the shoulder-joint, preventing displacement of the head of the humerus. [citation needed]