Upward rotation of the glenoid cavity during overhead abduction of shoulder occurs by -

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Upward rotation of the glenoid cavity during overhead abduction of shoulder occurs by -

  1. Trapezius and serratus anterior

  2. Latissimus dorsi and trapezius

  3. Trapezius and deltoid

  4. Pectoralis minor and serratus anterior

Explanation:

Muscles responsible for abduction of the shoulder joint

  •    Supraspinatus- first 15 degrees of abduction

  •    Deltoid (Acromial fibers)- it is responsible for abduction from 15 to 90 degrees.

  •    Trapezius and serratus anterior- They are responsible for upward rotation of the glenoid cavity.

The trapezius originates from the back of the skull and the spine of the neck and ribcage. It inserts onto the outer collarbone and shoulder blade. The upper part of the trapezius lifts the outer corner of the shoulder blade, while the lower part pulls the inner shoulder blade down. When both parts work together, they upwardly rotate the shoulder blade.

The serratus anterior originates along the inner edge of the shoulder blade. It passes under the shoulder blade and inserts onto the upper nine ribs. Its job is to pull the scapula around the side of the ribcage, assisting the trapezius with upward rotation.