Anatomy of the female breast

• Structure

The base of a normally developed female mammary gland extends from the 3rd to the 6th rib vertically and from the sternal to the anterior axillary line and horizontally, covering a significant part of the pectoralis major and a section of the anterior serratus muscle.

The glandular body itself consists of 15-20 cone-shaped lobules, which converge radially with their tops toward the nipple. The excretory ducts of one large lobule join into a milky duct, which is capped by a small funnel-shaped opening at the top of the nipple.

The mammary gland is located on the fascia of the pectoralis major muscle, with which it is connected by loose connective tissue. At the level of the II-III rib, the superficial fascia splits and forms a case for the mammary gland. From this case, connective tissue plates extend radially into its thickness, dividing the parenchyma and fatty tissue of the gland into lobes. The fascial case of the mammary gland is fixed to the clavicle by a dense strand of superficial fascia (Cooper's ligament). The mammary gland tissue is divided by localization into intra- and extracapsular. The latter is located most superficially.

• Blood supply

The blood supply to the mammary gland is provided by three different sources: 1) from the posterior intercostal arteries, 2) from the branches of the internal thoracic artery and 3) from the lateral thoracic artery. The branches of the posterior intercostal vessels supply the internal and, to a lesser extent, the lateral part of the gland. The main source of blood supply to the mammary gland is the internal thoracic artery. Its perforating branches exit through the four upper intercostal spaces directly next to the sternum. The largest vessel in 60% of cases is the second perforating branch, in 40% of cases - the third perforating branch. Damage to these vessels during endoprosthetics of the mammary glands leads to severe bleeding. Blood supply to the areola and nipple is provided by a rich network of arterial anastomoses located directly in the skin, formed by branches of all three sources. Venous drainage of the mammary gland is carried out through the deep and superficial veins. Deep veins accompany the arterial trunks, while the superficial venous network is located under the skin and is represented by a network of vessels with wide loops (circulus venosus Halleri).

• Lymphatic system

The lymphatic vessels of the mammary gland form a rich network and drain lymph in the following main directions: from its lateral sections to the axillary nodes, from the posterior section to the supraclavicular and subclavian, and from the superomedial section to the parasternal lymph nodes. As a rule, aesthetic operations on the mammary gland do not lead to significant disruptions in lymph drainage.

• Innervation

Innervation of the skin covering the gland is carried out from three main sources. The outer part of the mammary gland is supplied by the anterolateral cutaneous branches of the III-IV intercostal nerves, the inner part - by the anteromedial branches of the II-IV intercostal nerves, the upper part - by the branches of the supraclavicular nerve originating from the cervical plexus. In addition, branches of the medial and lateral thoracic nerves take part in the innervation of the mammary gland. Sensory innervation of the nipple-areolar complex is provided by the anterolateral cutaneous branch of the IV intercostal nerve, which at the level of the axillary line pierces the intercostal muscles and divides into posterior and anterior sensory branches. The latter continues to run at the level of the fourth intercostal space under the fascia of the anterior serratus muscle to the outer edge of the pectoralis major muscle and then, turning forward, enters the tissue of the gland.

The terminal branches consist of 5 bundles: three innervate the areola, one innervate the nipple, and the last innervate the parenchyma of the gland around the areola. When oriented according to a conventional clock face, the nerve conductors reach the right areola at 7 o'clock, and the left areola at 5 o'clock.

• Shape and size of mammary glands

The size and shape of the mammary glands vary greatly during different periods of a woman's life. During puberty, there are five successive periods of gland formation: initial - flat childhood shape; mound-shaped increase in volume with an increase in the diameter of the areola; general increase in the volume of the gland, as well as the areola, but without a clear formation of the contour of the areola and nipple; the areola and nipple are formed into a distinct secondary elevation; the mature mammary gland has a common contour with the areola and a protruding nipple. The juvenile conical mammary gland becomes mature over time with a gradual flattening of the upper and medial quadrants. The mammary gland is a highly sensitive hormone-dependent organ, which can be reflected in the shape and volume of the gland at different periods of a woman's menstrual cycle. During life, gravity and pregnancy affect the shape of the mammary gland and lead to its ptosis.

The ideal shape and size of a woman's breasts are determined in accordance with racial, national, socio-aesthetic and, to a large extent, individual ideas. The volume of a normal mammary gland, depending on a woman's constitution, height and body weight, can vary from 150 to 600 cm3. The nipple-areolar complex with a normal,

A developed mammary gland should always be located slightly above the projection of the submammary fold, which is usually located at the level of the sixth intercostal space.

The average statistical parameters of the "ideal" breast were calculated for a woman 162 cm tall and 17-18 years old. On average, the areola diameter is 3.7 cm and varies from 2.8 to 4.5 cm. The distance between the jugular notch and the nipple varies from 18 to 24 cm (on average 21 cm). The distance from the submammary fold to the nipple is on average 6.5 cm (from 5 to 7.5 cm). The internipple distance is 2 1 cm (from 20 to 24 cm). The nipple is usually located 1-2 cm lateral to the midclavicular line and 11-13 cm from the midline. Most parameters change significantly when the patient is lying down.

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