Shoulder Anatomy and Muscle Testing

Shoulder Anatomy

• Bones: Clavicle, scapula, humerus; form the shoulder girdle.
• Joints:
  • Glenohumeral Joint (ball-and-socket)
  • Acromioclavicular Joint (AC)
  • Sternoclavicular Joint (SC)
• Labrum: Cartilage that deepens the glenoid cavity.
• Bursae: Fluid-filled sacs to reduce friction.
• Muscles:
  • Rotator Cuff: Supraspinatus, Infraspinatus, Teres Minor, Subscapularis
  • Deltoid, Pectoralis Major, Biceps Brachii, Triceps Brachii.

Muscle Strength Testing

• Rotator Cuff Strength:
  • External Rotation: Infraspinatus and Teres Minor.
  • Internal Rotation: Subscapularis.
• Deltoid Strength: Shoulder abduction testing.
• Biceps and Triceps Strength: Arm flexion and extension.
• Procedure:
  • Isolate each muscle group.
  • Use a graded scale (0-5) for strength assessment.

Special Tests For Shoulder Injuries

• Apprehension Test: Assesses anterior instability.
• Sulcus Sign: Evaluates inferior glenohumeral instability.
• Jobe's Test (Empty Can Test): Checks supraspinatus muscle function.
• Drop Arm Test: Indicates rotator cuff tears.
• Speed's Test: Tests for biceps tendon pathology.

Impingement Tests

• Neer Test: Evaluates subacromial impingement.
• Hawkins-Kennedy Test: Assesses supraspinatus impingement.
• Cross-Body Adduction Test: Tests for AC joint problems.
• Painful Arc Test: Identifies pain during arm elevation (60-120 degrees).

Range Of Motion Assessment

• Active Range of Motion (AROM): Patient moves the shoulder voluntarily.
  • Flexion: 180 degrees
  • Extension: 50 degrees
  • Abduction: 180 degrees
  • Internal Rotation: 70 degrees
  • External Rotation: 90 degrees
• Passive Range of Motion (PROM): Examiner moves the shoulder; helps identify restrictions.
• Functional Testing: Assess daily activities and overhead activities to evaluate limitations.

Shoulder Anatomy

• The shoulder joint is comprised of three bones: clavicle, scapula, and humerus.
• The shoulder joint has three main articulations: glenohumeral joint, acromioclavicular joint, and sternoclavicular joint.
• Glenohumeral joint is a ball-and-socket joint that allows for extensive range of motion.
• Labrum, a cartilaginous structure, deepens the glenoid cavity, enhancing stability.
• Bursae are fluid-filled sacs that minimize friction during motion.
• Rotator cuff muscles: supraspinatus, infraspinatus, teres minor, and subscapularis; they contribute to shoulder stability and movement.

Muscle Strength Testing

• Rotator cuff muscles are assessed for external rotation (infraspinatus and teres minor) and internal rotation (subscapularis).
• Deltoid strength is tested by assessing shoulder abduction.
• Biceps and triceps strength is evaluated through arm flexion and extension.
• Muscle strength assessment involves isolating each muscle group and using a graded scale.

Special Tests for Shoulder Injuries

• Apprehension test is used to identify anterior instability.
• Sulcus sign helps determine inferior glenohumeral instability.
• Jobe's test (Empty Can Test) evaluates supraspinatus muscle function.
• Drop arm test is indicative of rotator cuff tears.
• Speed's test investigates biceps tendon pathology.

Impingement Tests

• Neer test assesses subacromial impingement.
• Hawkins-Kennedy test examines supraspinatus impingement.
• Cross-body adduction test investigates AC joint problems.
• Painful arc test highlights pain during arm elevation between 60 and 120 degrees.

Range of Motion Assessment

• Active range of motion (AROM) measures the patient's voluntary shoulder movement.
  • Flexion: 180 degrees
  • Extension: 50 degrees
  • Abduction: 180 degrees
  • Internal rotation: 70 degrees
  • External rotation: 90 degrees
• Passive range of motion (PROM) involves examiner moving the shoulder, aiding in identifying limitations.
• Functional testing is essential to assess daily activities and overhead movements, identifying functional limitations.

This quiz covers the anatomy of the shoulder, including key bones, joints, and muscles involved. It also evaluates your understanding of muscle strength testing and special tests for shoulder injuries. Test your knowledge on the structure and function of the shoulder girdle!