The scapula, also known as the shoulder blade, is the bone that connects the humerus with the clavicle. Like their connected bones, the scapulae are paired, with each scapula on either side of the body being roughly a mirror image of the other. The name derives from the Classical Latin word for trowel or small shovel, which it was thought to resemble.
The humerus is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of a rounded head, a narrow neck, and two short processes. The body is cylindrical in its upper portion, and more prismatic below. The lower extremity consists of 2 epicondyles, 2 processes, and 3 fossae. As well as its true anatomical neck, the constriction below the greater and lesser tubercles of the humerus is referred to as its surgical neck due to its tendency to fracture, thus often becoming the focus of surgeons.
The rotator cuff is a group of muscles and their tendons that act to stabilize the human shoulder and allow for its extensive range of motion. Of the seven scapulohumeral muscles, four make up the rotator cuff. The four muscles are the supraspinatus muscle, the infraspinatus muscle, teres minor muscle, and the subscapularis muscle.
The biceps or biceps brachii is a large muscle that lies on the front of the upper arm between the shoulder and the elbow. Both heads of the muscle arise on the scapula and join to form a single muscle belly which is attached to the upper forearm. While the biceps crosses both the shoulder and elbow joints, its main function is at the elbow where it flexes the forearm and supinates the forearm. Both these movements are used when opening a bottle with a corkscrew: first biceps screws in the cork (supination), then it pulls the cork out (flexion).
The coracoid process is a small hook-like structure on the lateral edge of the superior anterior portion of the scapula. Pointing laterally forward, it, together with the acromion, serves to stabilize the shoulder joint. It is palpable in the deltopectoral groove between the deltoid and pectoralis major muscles.
Shoulder problems including pain, are one of the more common reasons for physician visits for musculoskeletal symptoms. The shoulder is the most movable joint in the body. However, it is an unstable joint because of the range of motion allowed. This instability increases the likelihood of joint injury, often leading to a degenerative process in which tissues break down and no longer function well.
The human shoulder is made up of three bones: the clavicle (collarbone), the scapula, and the humerus as well as associated muscles, ligaments and tendons. The articulations between the bones of the shoulder make up the shoulder joints. The shoulder joint, also known as the glenohumeral joint, is the major joint of the shoulder, but can more broadly include the acromioclavicular joint. In human anatomy, the shoulder joint comprises the part of the body where the humerus attaches to the scapula, and the head sits in the glenoid cavity. The shoulder is the group of structures in the region of the joint.
In human anatomy, the infraspinatus muscle is a thick triangular muscle, which occupies the chief part of the infraspinatous fossa. As one of the four muscles of the rotator cuff, the main function of the infraspinatus is to externally rotate the humerus and stabilize the shoulder joint.
The shoulder joint is structurally classified as a synovial ball-and-socket joint and functionally as a diarthrosis and multiaxial joint. It involves an articulation between the glenoid fossa of the scapula and the head of the humerus. Due to the very loose joint capsule that gives a limited interface of the humerus and scapula, it is the most mobile joint of the human body.
The subscapularis is a large triangular muscle which fills the subscapular fossa and inserts into the lesser tubercle of the humerus and the front of the capsule of the shoulder-joint.
The shoulder girdle or pectoral girdle is the set of bones in the appendicular skeleton which connects to the arm on each side. In humans it consists of the clavicle and scapula; in those species with three bones in the shoulder, it consists of the clavicle, scapula, and coracoid. Some mammalian species have only the scapula.
The annular ligament is a strong band of fibers that encircles the head of the radius, and retains it in contact with the radial notch of the ulna.
The coracoclavicular ligament is a ligament of the shoulder. It connects the clavicle to the coracoid process of the scapula.
The glenoid fossa of the scapula or the glenoid cavity is a bone part of the shoulder. The word glenoid is pronounced or and is from Greek: gléne, "socket", reflecting the shoulder joint's ball-and-socket form. It is a shallow, pyriform articular surface, which is located on the lateral angle of the scapula. It is directed laterally and forward and articulates with the head of the humerus; it is broader below than above and its vertical diameter is the longest.
In human anatomy, the glenohumeral ligaments (GHL) are three ligaments on the anterior side of the glenohumeral joint. Reinforcing the anterior glenohumeral joint capsule, the superior, middle, and inferior glenohumeral ligaments play different roles in the stability of the head of the humerus depending on arm position and degree of rotation.
The coronoid process of the ulna is a triangular process projecting forward from the anterior proximal portion of the ulna.
Shoulder replacement is a surgical procedure in which all or part of the glenohumeral joint is replaced by a prosthetic implant. Such joint replacement surgery generally is conducted to relieve arthritis pain or fix severe physical joint damage.
The capsule of the glenohumeral (shoulder) joint is the articular capsule of the shoulder. It completely surrounds the joint. It is attached above to the circumference of the glenoid cavity beyond the glenoidal labrum, and below to the anatomical neck of the humerus, approaching nearer to the articular cartilage above than in the rest of its extent.
Shoulder impingement syndrome is a syndrome involving tendonitis of the rotator cuff muscles as they pass through the subacromial space, the passage beneath the acromion. It is particularly associated with tendonitis of the supraspinatus muscle. This can result in pain, weakness, and loss of movement at the shoulder.
Reverse shoulder replacement is a type of shoulder replacement in which the normal ball and socket relationship of glenohumeral joint is reversed, creating a more stable joint with a fixed fulcrum. This form of shoulder replacement is utilized in situations in which conventional shoulder replacement surgery would lead to poor outcomes and high failure rates.
