Chassaignac bursa

Chassaignac bursa (also known as the retromammary bursa, submammary serous bursa or occasionally Chassaignac bag) is the space behind the breast, lying between the pectoralis fascia posteriorly and deep layer of superficial fascia anteriorly.

It contains loose connective tissue and aids in mobility of the breast on the thoracic wall. Posteriorly it is bound by the pectoral fascia and anteriorly by the deep layer of the superficial fascia.

Radiographic appearance

Mammography

Chassaignac bursa is a lucency in the mammogram and its radiological significance lies in the fact that it must be seen in all optimally performed craniocaudal and mediolateral oblique mammograms.