Answer:
The upper lateral quadrant.
Step-by-step explanation:
The breast is a glandular and fatty tissue that lies on the top of the pectoral muscles of the chest. It is made up of fatty tissues, glands, and connective tissue ligaments that attach it to the muscles.
The glands are the functional units as they are where the milk is produced. These glands are divided into 15 to 20 lobes of glands demarcated by fatty and connective tissues. Each lobe is made up of lobules where milk is produced. They are various ducts that carry the milk and they open up on the nipple.
The breast is usually divided into four imaginary quadrants during clinical examination. The upper lateral quadrant has an extension of breast tissues into the armpit. This is referred to as the Tail of Spence or axillary tail.
The tail of Spence has axillary lymph nodes around it and plays a key role in the diagnosis of breast cancer.