20 December 2010
The shoulder is one of the most amazing joints in the body. Categorized as a ball-and-socket joint, the shoulder has flexibility unlike other joints in the body.
The shoulder is made up of an orchestration of bones, ligaments, muscles and the main joint. There are two specific and main bones that make up the shoulder; the humerus and the scapula – most commonly known to most people as the shoulder blade. The end of the scapula is known as the glenoid, and is the part of the scapula that meets the head, or the ball, of the humerus to form this ball-and-socket joint.
Ligaments and tendons work in the shoulder as well. Ligaments are used to connect the humerus and scapula, and tendons are responsible for adhering the muscle system of the shoulder to the bones. The biceps muscle is also involved in the shoulder – a tendon helps stabilize the joint of the shoulder and connects the muscle to the bone.
In the back of the shoulder (scapula, or shoulder blade), there are four muscles on the scapula that are involved with the formation and function of the rotator cuff. The rotator cuff is the actual attachment of the arm to the shoulder, and is at the crest, or round part of the shoulder.
The scapula, or shoulder blade is an important bone in shoulder anatomy – it is responsible for the attachment of several muscles that play a large part in the movement and stability of the shoulder. The scapula is located at the top of the back of the ribcage, however, it is not connected to the rib cage. It is only connected to the clavicle, which is commonly known as the collarbone, and is attached to the humerus.
The clavicle, while not a major part of shoulder anatomy, is connected to the shoulder joint, and helps with and is essential to shoulder joint support.
The most common shoulder injury is an injury of the rotator cuff, which include tendonitis and tears. Rotator cuff tendonitis comes on gradually, while a tear will happen spontaneously, but may worsen with time.
To prevent shoulder injuries, it is important to properly stretch before exercise or activities involving the shoulder, and to rest when feeling muscle strain or pain.
References:
Raj, (2008) Raj’s Practical Management of Pain.415. (Benzon, Rathmell, Wu, Turk, Argoff Eds.)Philadelphia: Mosby Elsevier
eOrthopod Website at: www.eorthopod.com
