Anatomy
Summary
The primary function of the breast is lactation. Lactation starts in the lobules, also known as alveoli, where milk-creating cuboidal cells produce breast milk. The flow of breast milk continues through the lactiferous ducts, pooling momentarily in the lactiferous sinus before exiting via the nipple. Due to the density of breast tissue, the upper outer quadrant is the most frequent site for occurences of breast cancer, which is the most commonly diagnosed cancer in females. In advanced cases, cancerous cells may infiltrate axillary lymph nodes and cause skin changes like peau d'orange or skin dimpling due to the infiltration of suspensory ligaments.
Surgical intervention often involves axillary lymph node dissection, which comes with its own set of complications, primarily nerve injuries. Damage to the long thoracic nerve can result in a winged scapula and abduction weakness. Thoracodorsal nerve injury impairs arm adduction and internal rotation, while injury to both medial and lateral pectoral nerves results in weakened arm movements including adduction, internal rotation, flexion, and extension. Finally, an intercostobrachial nerve injury can cause sensory dysfunction in the axilla and the medial upper arm.
Lesson Outline
Don't stop here!
Get access to 51 more Anatomy lessons & 13 more medical school learning courses with one subscription!
FAQs
The mammary glands are essential components of the breast anatomy that produce milk after pregnancy. Each breast contains 15 to 20 lobes of glandular tissue, which further divides into lobules containing alveoli. The alveoli are responsible for milk production. The milk is then transported to the lactiferous sinus and through a network of tiny tubes called lactiferous ducts that lead to the nipple.
The axilla, or armpit, is closely associated with the breast as it contains the axillary lymph nodes, which filter lymph fluid from the breast and upper limb. The axilla also houses structures like the intercostobrachial nerve, major blood vessels and various muscles, which have a direct or indirect impact on the breast's anatomical and functional aspects. Cancer or surgery in this aread can therefore lead to a wide variety of complications.
"Peau d'orange," french for "orange peel skin," is a term used to describe a particular appearance of the skin overlying the breast where it resembles the rough, dimpled surface of an orange peel. It is often a sign of inflammatory breast cancer, a rare but aggressive type of breast cancer. This symptom occurs due to blockage of the lymphatic vessels in the skin by cancer cells, leading to swelling and redness.
Axillary lymph node dissection is a surgical procedure commonly performed when breast cancer has spread to the axillary, or underarm, lymph nodes. It involves removing anywhere from a small cluster to a large number of these nodes, which are then examined for signs of cancer. This helps to determine the stage of the cancer and guide subsequent treatment options.
The intercostobrachial nerve arises from the upper thoracic spinal nerves and passes through the axilla. It provides sensory innervation to the skin of the upper lateral part of the arm but may also send some sensory branches to the skin over the upper lateral part of the breast. Consequently, damage to this nerve during axillary surgery may lead to numbness and tingling in its area of innervation.
