The Shoulder Joint Pain
There are two shoulder joints in the human body that serve as connectors between each arm and the torso. It is a ball and socket joint where the top (or head) of the upper arm bone (medically known as the humerus) is located in a groove in the shoulder blade (also known as the scapula) of the human back. The socket or groove in which it is located is known as the glenoid. The acromion is another bone of the human body that is located directly above this ball and socket joint. The acromioclavicular joint is located adjacent to this and is more simply known as the AC joint. The acromion is a space in the body that is prone to the formation of bone spurs while the acromioclavicular joint is the common place where shoulder separations are formed. There are a group of four muscles attached to these joints that ensure seamless movement of the arm in terms of raising and rotating it. This group of muscles is known as the rotator cuff. This part of the body is slightly more prone to injury as the ball of the joint which is the top end of the upper arm is much larger than the socket it sits in.
A dislocation of the shoulder is usually when the ball and socket joint comes apart as is the case when extreme rotation forces the ball out of the socket or a strong force pushes the shoulder outward (known as abduction). The shoulder joint is the most frequently dislocated joint and while it is painful it can be put back into place and repaired well.
When the scapula (or shoulder blade) is not joined to the collar bone (medically known as a clavicle) it results in the separation of the shoulder. This usually occurs when the ligaments of the shoulder joint are partially or fully torn or ruptured.
When the structures surrounding the 4 rotator cuff muscles pinch or squeeze the muscles in some way it causes a certain degree of damage. This results in the inflammation, redness, soreness and swelling of the tendons that hold the shoulder in place. There are also bursa sacs that protect the shoulder in the area that can get inflamed. When the tendons are inflamed it is known as tendonitis and when the bursa sacs are inflamed it is known as bursitis.
There are 2 types of arthritis that affect the shoulder joint – osteoarthritis and rheumatoid arthritis. The former occurs due to damage caused by wear and tear of the cartilage and the latter due to the inflammation of the joint. Arthritis does not affect the bones in the joint alone but also harms the surrounding muscles, tendons and ligaments.