Patient/caregiver was instructed regarding anatomy of shoulder joint as follows:
- The shoulder joint is formed by three bones: upper arm bone (humerus), shoulder blade (scapula), and the collar bone (clavicle).
- The shoulder joint is mainly a ball and socket joint, in which the ball of the joint is formed by the round head of humerus. The socket is a hollow in the scapula or shoulder blade, which is called glenoid. The head of humerus sits in the hollow glenoid forming the shoulder joint.
- Clavicle, the third bone in the shoulder joint, meets the scapula on one end forming the roof of the shoulder joint. On the other end, collar bone meets the sternum or breastbone on front of the chest and supports the connection of the arm to the main skeleton.
- The ball and socket arrangement of shoulder joint offers some stability and wide range of motion to the shoulder joint.
- The shoulder joint is enclosed in or surrounded by a joint capsule, which is known as a synovium. This joint capsule is a watertight sac surrounding the shoulder joint, formed by the strong ligaments of the joint.
- The synovium has fluid called synovial fluid, which lubricates the joint and helps with the smooth rolling of bones in the joint on one another during movement.
- The head of humerus is covered by articular cartilage and has a soft, smooth, and rubbery consistency. The hollow of the glenoid is also lined by the same soft, smooth articular cartilage.
- The smooth and soft articular cartilage lining the glenoid and covering the head of humerus helps with easy sliding of the bones against each other and allows an easy range of motion.
- Also, the articular cartilage helps as a shock absorber and helps to prevent the friction due to rubbing of the bones against each other.
- Various connective tissue bands, such as, ligaments and tendons, add more stability and reinforce the shoulder joint in the body.
- In the upper limb, arteries & veins providing blood supply & venous drainage and nerves providing nerve supply to the upper limb travel in close relation to the shoulder joint. These structures can be at risk for injury, secondary to injury to the shoulder joint, thus compromising the blood and nerve supply to the upper limb.
