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Head of the humerus. The head (caput humeri), is nearly hemispherical in form. It is directed upward, medialward, and a little backward, and articulates with the glenoid cavity of the scapula to form the glenohumeral joint (shoulder joint). The circumference of its articular surface is slightly constricted and is termed the anatomical neck, in ...
The greater tubercle of the humerus is the outward part the upper end of that bone, adjacent to the large rounded prominence of the humerus head. It provides attachment points for the supraspinatus, infraspinatus, and teres minor muscles, three of the four muscles of the rotator cuff, a muscle group that stabilizes the shoulder joint.
In dinosaurs the main bones of the pectoral girdle were the scapula (shoulder blade) and the coracoid, both of which directly articulated with the clavicle. The place on the scapula where it articulated with the humerus (upper bone of the forelimb) is called the glenoid. The glenoid is important because it defines the range of motion of the ...
Around the joint space are muscles - the rotator cuff, which directly surrounds and attaches to the shoulder joint - and other muscles that help provide stability and facilitate movement. Two filmy sac-like structures called bursae permit smooth gliding between bone, muscle, and tendon. They cushion and protect the rotator cuff from the bony ...
Animation of the shoulder joint. The muscles shown are subscapularis muscle (at right), infraspinatus muscle (at top left), teres minor muscle (at bottom left) The movement of the scapula across the rib cage in relation to the humerus is known as the scapulohumeral rhythm, and this helps to achieve a further range of movement. This range can be ...
The supraspinatus muscle performs abduction of the arm, and pulls the head of the humerus medially towards the glenoid cavity. [5] It independently prevents the head of the humerus from slipping inferiorly. [5] The supraspinatus works in cooperation with the deltoid muscle to perform abduction, including when the arm is in an adducted position. [5]
The greater tubercle projects as the most lateral structure of the humeral head. Medial to this, in turn, is the lesser tubercle of the humeral head. The subscapularis muscle origin is divided from the remainder of the rotator cuff origins as it is deep to the scapula. The four tendons of these
A SLAP lesion (superior labrum, anterior to posterior) is a tear where the glenoid labrum meets the tendon of the long head of the biceps muscle. Symptoms include increased pain with overhead activity, popping or grinding, loss of strength, and trouble localizing a specific point of pain. [ 3 ]