axillary fascia axillary fascia the pectoral fascia is very thin over the upper part of the pectoralis major, but thicker in the interval between it and the latissimus dorsi, where it closes in the axillary space and forms the axillary fascia. axillary fascia, together with the skin, forms the base of the axilla. axillary fasciadetailsidentifierslatinfascia axillarista98a04.6.03.002ta22537fma37329anatomical terminology