Axillary Fascia

fascia axillaris

The axillary fascia is the deep fascia that forms the floor of the armpit, stretching between the lower borders of pectoralis major in front and latissimus dorsi behind. It is pulled upward into the familiar hollow of the armpit by the suspensory ligament of the axilla, a continuation of the clavipectoral fascia.

Anatomical Data

Boundaries & Contents

Location	The floor (base) of the axilla, deep to the armpit skin.
Boundaries	Pectoralis major lower border in front Latissimus dorsi lower border behind Continuous with the pectoral, brachial and serratus fasciae Suspensory ligament of the axilla attaching it to the clavipectoral fascia above

Biomechanics

Function & Actions

Closes the base of the axilla and, through the suspensory ligament, maintains the armpit hollow.

Clinical Relevance

Clinical Notes

This fascia lies just under the hair-bearing skin of the armpit and is crossed by lymphatics from the breast and arm, so it is opened in axillary node dissection. Inflamed sweat glands (hidradenitis suppurativa) and abscesses lie superficial to it. Its upward pull explains why the armpit hollows out when the arm is abducted.

Pathology

Common Injuries & Conditions

Axillary Abscess

A collection of pus in the armpit, often from infected hair follicles or sweat glands, lying superficial to or tracking through the axillary fascia and needing drainage.

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