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VIDEO
CONTENT
QUIZ
MATERIALS
Quick Facts
Key Features
Origin
Insertion
Actions
Clinical Correlates
Quick Facts
- Origin: Posterior aspect of inferior angle of scapula.
- Insertion: Crest of lesser tubercle of humerus.
- Action: Adducts and medially rotates arm at glenohumeral (shoulder) joint.
- Innervation: Lower subscapular nerve (C5-C7).
- Arterial Supply: Circumflex scapular, subscapular, and posterior circumflex humeral arteries.
Key Features & Anatomical Relations
- Type: Thick, fusiform skeletal muscle.
- Location: In the shoulder region.
- Anatomical Relations:
- Anterior to the long head of triceps brachii muscle.
- Posterior to the scapula and coracobrachialis muscle.
- Superior to the latissimus dorsi muscle.
- Inferior to the teres minor and infraspinatus muscles.
- Functional Role: Contributes to the posterior wall of the axilla and formation of the posterior axillary fold.
Origin
- The teres major muscle originates from the posterior aspect of the inferior angle of the scapula and its adjacent area.
Insertion
- The muscle fibers travel superolaterally, inserting onto the crest of the lesser tubercle of the humerus via a flat tendon.
- The insertion site is medial to that of the latissimus dorsi muscle.
Actions & Testing
- Actions:
- Adducts the arm at the glenohumeral joint.
- Medially rotates the arm at the glenohumeral joint.
- Assists in extending the arm at the glenohumeral joint.
- Helps stabilize the glenohumeral joint.
- Testing:
- The muscle is tested by adducting the arm at the glenohumeral joint against resistance
Injury or Rupture of the Rotator Cuff
Definition and Overview
- Rotator Cuff: A group of muscles and tendons surrounding the shoulder joint, maintaining the stability and facilitating movement.
- Injury/Rupture: Can range from inflammation (tendinitis) to tears in the muscles or tendons.
Causes
- Overuse: Repetitive arm activities, especially overhead motions.
- Age: Degenerative changes in older adults.
- Trauma: Acute injuries from falls or accidents.
- Occupation/Sports: Activities requiring repetitive arm motions.
Symptoms
- Pain: Especially when lifting the arm or at night.
- Weakness: Difficulty in lifting or rotating the arm.
- Limited Mobility: Reduced range of motion in the shoulder.
- Swelling and Tenderness: Around the shoulder region.
Diagnosis
- Physical Examination: Assessing range of motion and muscle strength.
- Imaging Tests: MRI, Ultrasound, or X-rays to visualize tears or inflammation.
- Arthroscopy: Invasive procedure for a detailed view, if needed.
Treatment
- Conservative:
- Rest: Avoiding activities that aggravate symptoms.
- Physical Therapy: Strengthening and stretching exercises.
- Medications: Pain relievers and anti-inflammatory drugs.
- Surgical:
- Arthroscopic Surgery: For repairing tears.
- Open Shoulder Surgery: In more severe cases.
- Tendon Transfer: If the torn tendon is irreparable.
Prevention
- Exercise: Regular strengthening and flexibility exercises for shoulder muscles.
- Proper Technique: Using correct form during sports or occupational activities.
- Ergonomics: Adjusting workspace to reduce strain on the shoulder.
- Warm-Up: Before engaging in physical activities.
