Lecture on Rotator Cuff and Shoulder Movement

Rotator Cuff (CU)

• Purpose: Stabilizes the GH (glenohumeral) joint
• Muscles Involved: Four muscles forming around the humeral head
  • Suprasupinatus
  • Infraspinatus
  • Teres Minor
  • Subscapularis
• Acronym: SITS
• Function: Each muscle contributes differently to shoulder movements

Scapular Plane (Scaption)

• Definition: Movement along the scapular plane (30 degrees anterior to the frontal plane)
• Importance: Provides a secure movement pattern, used frequently in rehabilitation
• Application: More common in Occupational Therapy (OT) vs. Physical Therapy (PT)
• Movement Example: Abduction to about 30 degrees and then raising the arm diagonally

Shoulder Complex

Shoulder Girdle and Shoulder Joint

• Combined Movement: Movements measured as a combination of girdle and joint
• Evaluation: Range of Motion (ROM) evaluation must consider both GH joint and scapular movement

Scapulohumeral Rhythm

• Ratio: 2:1 ratio between GH joint and scapula
• Movement: Initial 30 degrees purely GH joint; thereafter, combination of GH and scapula
• Example: Shoulder abduction
  • 120 degrees by GH joint
  • 60 degrees by scapula (30 degrees AC joint + 30 degrees SC joint)

Common Shoulder Pathologies

• Bone Fracture
• Dislocation: Common in stroke patients with hypo/hypertonia
• Impingement Syndrome: Compression between acromion arch and humeral head
• Rotator Cuff Injuries: Supraspinatus often involved
• Bicipital Tendonitis: Affects the biceps long head

Summary

• Key Points Covered: Shoulder girdle, joint structure, muscle functions, common injuries
• Importance: Understanding the complex interactions between ligaments, muscles, and joints

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