When the arms and shoulders are fixed,by leaning on the elbows or grasping onto a table,this muscle can use its insertion as its origin and facilitate an increase in the A-P diameter of the thorax.

Question

Quizplus · Accepted Answer

When the insertion and origin of the pectoralis muscle are reversed by leaning on a table to fix the arms,the muscle will pull on the anterior chest wall,lifting the ribs and sternum to increase the A-P diameter of the thoracic cage.

When the Arms and Shoulders Are Fixed,by Leaning on the Elbows