Describe the rotator cuff muscles, including their origins, insertions, and actions.

Here is a description of the rotator cuff muscles:

The rotator cuff is a group of four muscles that surround the shoulder joint, providing stability and enabling a wide range of motion. They originate from the scapula and insert onto the humerus.

• Supraspinatus:
  • Origin: Supraspinous fossa of the scapula.
  • Insertion: Greater tubercle of the humerus.
  • Action: Initiates abduction of the arm (first 15 degrees).
• Infraspinatus:
  • Origin: Infraspinous fossa of the scapula.
  • Insertion: Greater tubercle of the humerus.
  • Action: Laterally rotates the arm.
• Teres Minor:
  • Origin: Lateral border of the scapula.
  • Insertion: Greater tubercle of the humerus.
  • Action: Laterally rotates the arm.
• Subscapularis:
  • Origin: Subscapular fossa of the scapula.
  • Insertion: Lesser tubercle of the humerus.
  • Action: Medially rotates the arm.

Collectively, these muscles work to stabilize the head of the humerus within the glenoid cavity of the scapula, forming a "cuff" around the shoulder joint. They are crucial for overhead movements and preventing dislocation.