VIDEO
CONTENT
QUIZ
MATERIALS
Quick Facts
Key Features
Origin
Insertion
Actions
Clinical Correlates
Arterial Supply
Innervation
Quick Facts:
- Origin: Subscapular fossa of the scapula.
- Insertion: Lesser tubercle of the humerus.
- Action: Medially rotates and stabilizes the arm at the glenohumeral (shoulder) joint.
- Innervation: Upper and lower subscapular nerves (C5-C7).
- Arterial Supply: Subscapular, suprascapular, and lateral thoracic arteries.
Key Features & Anatomical Relations:
- A thick, multipennate skeletal muscle.
- Located:
- Anterior (deep) to the scapula, the glenohumeral joint, and the subtendinous bursa of the subscapularis muscle.
- Posterior to the serratus anterior and teres minor muscles, and the axillary artery and vein.
- Superior to the teres major and latissimus dorsi muscles.
- Lateral to the rhomboid major and minor muscles.
- Contributes to the posterior wall of the axilla.
Origin:
- From the subscapular fossa of the scapula and the aponeurosis surrounding the muscle.
Insertion:
- Fibers travel superolaterally and insert via a broad tendon onto the lesser tubercle of the humerus.
- Part of the tendon merges with the capsule of the glenohumeral joint.
Actions:
- Medially rotates the arm at the glenohumeral joint.
- One of the four rotator cuff (SITS) muscles, working to stabilize the glenohumeral joint by holding the head of the humerus in the glenoid fossa of the scapula during movements.
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.
Arteria Subscapularis
Origin: Arises from the axillary artery (third part).
Course: Runs from the inferior border of the subscapularis muscle to the inferior scapular angle.
Branches: Gives rise to the circumflex scapular and thoracodorsal arteries.
Supplied Structures: Supplies the scapular and deltoid regions.
Arteria Suprascapularis
- Origin: Thyrocervical trunk of the subclavian artery.
- Course: Laterally parallel to the clavicle, inferiorly across the suprascapular notch, and deep to the inferior scapular notch.
- Branches: Acromial, muscular, suprasternal, and articular branches, anastomosis with the thoracoacromial and posterior circumflex scapular arteries.
- Supplied Structures: Sternocleidomastoid, supraspinatus, and infraspinatus muscles, scapula and clavicle, acromioclavicular and glenohumeral joints, cutaneous supply to the superior thorax and shoulder region.
Arteria thoracica lateralis
- Origin: Axillary artery.
- Course: Inferiorly along the lateral thoracic wall.
- Branches: Lateral mammary branches.
- Supplied Structures: Serratus anterior, pectoralis major and minor, and subscapularis muscles, axillary lymph nodes.
Superior and inferior subscapular nerve
Origin: Posterior cord of the brachial plexus. Course: Runs inferiorly along the posterior wall of the axilla.
Branches: No named branches.
Supply: Motor innervation. Supplies the teres major and subscapularis muscles.
