What are the force couples of the scapula?


What are the force couples of the scapula?

A scapular force couple is produced by the trapezius and serratus anterior during upward rotation of the scapula with arm elevation. Though the trapezius and serratus anterior are producing linear opposing forces, there is no linear translation of the scapula. Upward rotation of the scapula assists arm elevation.

Which muscles are part of the force couple that work together to downward rotate the scapula or rotate the glenoid fossa downward?

The rhomboids and lower trapezius assist in depression and downward rotation of the scapula in relation to the trunk (Table 8). The shoulder abductors and rotator cuff muscles act as stabilizers, controlling scapulohumeral alignment.

What causes downward rotation of scapula?

Downward rotation is accomplished by the force of gravity as well as the latissimus dorsi, levator scapulae, rhomboids, and the pectoralis major and minor muscles. Through these six motions, the scapula allows full function of the shoulder joint, one of the most mobile and versatile joints in the human body.

What is the prime mover of scapular downward rotation?


Action of the Scapula What the Action Looks Like (Try It Yourself) Primary Muscles
Upward rotation Lift the arms overhead; scapulae will follow and rotate upward Upper and middle trapezius
Downward rotation Return the arms downward from the overhead Rhomboids

What are force couple relationships?

Force couples are when 2 or more muscles on opposing sides of a joint work together to provide joint stability or create movement.

What muscles abduct the scapula?

The trapezius and serratus anterior muscles work in tandem to coordinate rotation and movement of the scapula to accommodate the full range of motion of the arm. Specifically, they facilitate abduction of the arm from 90 degrees and further upwards.

What are the 5 scapular stabilizing muscles?

The muscles that comprise the scapular stabilizers are the:

  • Serratus anterior– Which upwardly rotates the scapula.
  • Trapezius – Upper fibers that elevate and upwardly rotate the scapula.
  • Middle fibers – Adduct or retract the scapula.
  • Lower fibers – Which depress and rotate the scapula.
  • Levator Scapula and Rhomboids.