Hey, everyone. It’s Matt from Kenhub! And this tutorial, we will discuss the glenohumeral joint.
The shoulder joint or glenohumeral joint is the most flexible joint in the human body. Due to its numerous ligaments and muscles, it is also a strong and powerful ball-and-socket joint.
The shoulder joint consists of the humeral head and the socket known as the glenoid cavity. The socket is part of the scapula and is enlarged by the glenoid labrum, a lip of fibrocartilage.
The articular capsule which completely surrounds the cavity is reinforced by several ligaments, including the coracohumeral ligament and the glenohumeral ligaments.
The muscle system is significantly important for the stability and movements in the shoulder joint, especially the rotator cuff.
The rotator cuff consists of the following four muscles: subscapularis muscle, teres minor muscle, infraspinatus muscle, and supraspinatus muscle.
The functions of this muscle group are various. On the one hand, the fix the humeral head to the socket. On the other hand, they execute different movements. They allow both the internal and external rotation of the humeral head, and furthermore, abduction, adduction, and retroversion.
The long tendon of the two-headed biceps brachii muscle originates at the supraglenoid tubercle and passes through the rotator cuff.
The origin of the short tendon of the biceps is the coracoid process or raven’s beak extension.
The contraction of the biceps brachii muscle leads to an abduction, adduction, or anteversion, depending on the particular contracting part.
The acromion (the highest point of the shoulder) is a bony part of the scapula. Together with the coracoid process, it forms a cavity in which the humeral head and the tendon of the supraspinatus muscle moves.
This cavity comprises the subacromial bursa, an important synovial bursa which provides buffer-reducing compression and friction forces.