Common Shoulder Injuries

1. Rotator Cuff Tendonitis / Tear

• Area of Pain: Deep ache in the front and outer side of the shoulder, often radiating down the upper arm (deltoid area). Pain typically worsens when lifting the arm overhead or sleeping on the affected side.

• Affected Anatomy: The group of four muscles and their tendons—supraspinatus, infraspinatus, teres minor, and subscapularis—that hold the humerus (upper arm bone) head in the glenoid socket. The supraspinatus tendon is most commonly involved.

• Explanation: Micro-tears or full-thickness tears occur due to acute trauma (like a heavy lift or fall) or chronic wear and tear from repetitive overhead movements (overhead pressing, throwing, swimming).

2. Shoulder Impingement Syndrome (Subacromial Bursitis)

• Area of Pain: Top and outer aspect of the shoulder, especially noticeable when reaching overhead, behind the back, or reaching out to the side.

• Affected Anatomy: The subacromial bursa and rotator cuff tendons passing through the narrow subacromial space (the gap between the acromion bone on the shoulder blade and the humerus).

• Explanation: When the arm is raised, the space narrows. Irritation or bone spurs can cause the acromion to pinch (impinge) on the underlying tendons and fluid-filled bursa, leading to inflammation and pain.

3. Glenoid Labrum Tear (SLAP or Bankart Lesion)

• Area of Pain: Deep inside the shoulder joint, often accompanied by a popping, catching, or locking sensation, and a feeling of instability.

• Affected Anatomy: The labrum, a ring of soft fibrocartilage that lines the edge of the socket (glenoid) to deepen it and keep the humerus head centered.

• Explanation:

  • SLAP Tear: Involves the top (superior) part of the labrum where the long head of the biceps tendon attaches. Common in overhead throwers or after sudden pulling movements.

  • Bankart Lesion: Involves the lower (inferior) part of the labrum, typically occurring after an anterior shoulder dislocation.

4. AC Joint Sprain ("Separated Shoulder")

• Area of Pain: Sharp pain localized directly at the top point of the shoulder, often visible as a hard bump or prominence.

• Affected Anatomy: The acromioclavicular (AC) joint and its supporting ligaments, which connect the acromion of the scapula to the clavicle (collarbone).

• Explanation: Resulting from direct trauma, such as landing directly on the point of the shoulder during sports or a fall, tearing the ligaments that hold the collarbone and shoulder blade together.

5. Adhesive Capsulitis ("Frozen Shoulder")

• Area of Pain: Generalized, diffuse ache across the entire shoulder joint accompanied by severe stiffness and loss of both active and passive motion.

• Affected Anatomy: The glenohumeral joint capsule, a thick band of connective tissue surrounding the ball-and-socket joint.

• Explanation: The shoulder capsule becomes thick, stiff, and inflamed, leading to adhesions (bands of scar tissue). It typically progresses through freezing, frozen, and thawing stages over several months.