Fig. 5

Drawings illustrate the classification scheme for PAES. (a) Type 1: the medial head of the gastrocnemius muscle has normal insertion, displacing the popliteal artery around and beneath the muscle. (b) Type II: the medial head of the gastrocnemius arises from an abnormal position, displacing the popliteal artery medially. (c) Type III: entrapment is caused by an abnormal slip of the gastrocnemius muscle. (d) Type IV: entrapment is caused by a fibrous band or by the popliteal muscle