Understanding the Shoulder Joint
The shoulder is a complex structure formed by three bones:

Clavicle (Collarbone)

Scapula (Shoulder Blade)

Humerus (Upper Arm Bone)

A prominent part of the scapula, called the acromion, forms the top of the shoulder.

The Four Shoulder Joints
The shoulder actually consists of four separate joints working together, allowing an extensive range of movement. The main joint, known as the glenohumeral joint, is a ball-and-socket joint where the rounded head of the humerus fits into the shallow socket of the scapula, called the glenoid.

Unlike the hip, the shoulder socket is shallow, making it less stable but highly mobile. To enhance stability, the socket is deepened by a ring of firm tissue called the labrum, which surrounds the joint. This, combined with ligaments, muscles, and tendons, keeps the shoulder stable during complex movements such as throwing.

The Rotator Cuff
The rotator cuff is a group of four muscles and their tendons that surround the shoulder joint. These muscles originate from the scapula and attach to the humerus, helping move and stabilize the shoulder. Additionally, one of the biceps tendons passes through the shoulder joint, providing extra support.

Bursae and Smooth Movement
Between the rotator cuff and the acromion lies two small fluid-filled sacs called bursae. These act as cushions to reduce friction and allow smooth gliding of tendons over bone.

Common Shoulder Problems
Because of its unique anatomy, the shoulder is the most frequently dislocated major joint. Most shoulder problems involve the muscles, ligaments, and tendons rather than the bones.

Causes of Shoulder Injuries
Sports requiring overhead motions, such as swimming, tennis, and cricket.

Daily activities like painting, hanging curtains, or gardening.

Symptoms and Impact
Shoulder injuries can cause pain, disturb sleep, and limit the ability to perform everyday tasks or sports.

Diagnosis
The arthroscope — a small camera inserted into the joint — is the most accurate tool for diagnosing shoulder problems.