The infraspinatus and teres minor muscles lie together beneath a very strong membrane which is firmly attached to bone at the margins of these muscles. It is attached above to the lower border of the scapular spine beneath the deltoid muscle, and medially along the vertebral border of the scapula. It is attached to the axillary border of the scapula along the sinuous ridge that can be seen running down from the infraglenoid tubercle. Examine a scapula and note that this ridge runs back to the dorsal surface of the bone above the origin of teres major. The latter muscle does not lie beneath the fascia.
The importance of the infraspinatus fascia is not confined to its value as a landmark in surgical exposures of this region, but lies in the fact that in fracture of the blade of the scapula the resulting haematoma is confined beneath the fascia. A large rounded swelling that is limited to the margins of the bone is diagnostic of fracture.