Retraction

Retraction and its synonym retrusion have several medical uses:

• general anatomical movement posteriorly e.g. retraction of the shoulders when standing with arms held behind the back; the opposite to protraction or protrusion
• the drawing back of cut skin, muscle or other tissue surgically to obtain better exposure
• the failure of uterine muscle fibre relaxation after successive contractions aiding in the passage of fetus down the birth canal
• the gradual movement of teeth into a more orthodox position with dental appliances