Axillary process
Processus axillaris
- Latin synonym: Processus lateralis
- Synonym: Axillary tail
- Eponym: Tail of Spence
- Related terms: Axillary process; Axillary tail
Definition
The axillary process of the mammary gland (Axillary tail of Spence) is an extension of breast tissue that projects superolaterally from the upper outer quadrant of the breast toward the axilla. It passes through an opening in the deep fascia called the foramen of Langer to enter the axillary fossa.
Key anatomical features:
It represents a prolongation of the glandular tissue of the breast that extends along the inferolateral edge of the pectoralis major muscle into the axilla
It is clinically significant because it may be mistaken for axillary lymphadenopathy or a lipoma on physical examination
It is the most common site of accessory breast tissue and the most frequent location for breast pathology, as the upper outer quadrant (including the axillary tail) contains the greatest proportion of glandular tissue (~50%)
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