Axillary region

On the upper limb, which includes its belt (humeral) and the free part of the upper limb, a number of bone and muscle orientations are easily determined. This is the shoulder of the scapula, the acromial process, the medial and lateral margins, and the lower angle of the scapula. In the subclavian region, the clavicle and the coracoid scapula of the scapula are visible. The deltoid region, delimited in front of the large pectoral muscle by the deltoid-thoracic furrow, is occupied by a massive deltoid muscle. The axillary region corresponds to the axillary fovea, which is clearly visible in the retracted arm, the anterior border of which is defined along the lower edge of the large pectoral muscle, and the posterior border is defined along the lower edge of the latissimus muscle of the back. The medial and lateral grooves are seen on the shoulder, passing distally to the ulnar fossa and delimiting the anterior muscle group of the shoulder from the posterior one. Near the ulnar fold, the medial and lateral epicondyle of the humerus is easily felt, and the elbow process extends on the dorsal side of the elbow joint. On the front surface of the forearm slightly contoured radial and ulnar fissures, as well as the flexor tendon of the wrist and hand. Slightly proximal to the line of flexion - extension of the wrist joint is probed the styloid process of the radial and ulnar bones. The palms of the thumb and thumb are visible on the palm of your hand, and between them is the palm depression of a triangular shape, the base of which is turned towards the fingers. The places of the articular lines between the phalanges and the pads of the fingers are well marked. The back surface of the hand is convex. At the base of the thumb, when it is withdrawn between the sinews of the long and short extensors of the big toe, a fossa, called the anatomical snuff-box, is visible. Here, in the depth, under the fascia, the radial artery goes in an oblique direction, going to the palm through the first interdigital space.

The skin in the scapula is thick, closely welded to the subcutaneous tissue and with the superficial fascia by numerous fibrous fibers. Above the deltoid muscle, the skin is also thick, inactive. In the subclavian area, the skin is thin, here subcutaneous tissue is well developed, especially in women.

The axillary region opens with the upper limb withdrawn. It has the shape of an axillary fossa, bounded by the lower edge of the large pectoralis muscle (front) and the latissimus muscle of the back (behind). The medial border passes along the line connecting the lower edges of these muscles, which corresponds to the third edge. The lateral border is located on the medial surface of the shoulder along a line connecting the edges of the muscles attached to the humerus of the muscles mentioned above. The skin of the axillary fossa, beginning with the period of puberty, has a scalp. There are a lot of sweat and sebaceous glands in the skin. Subcutaneous fat is weakly expressed. In the shoulder area, the skin has a different thickness. In the lateral and posterior parts it is thicker than in the medial, the subcutaneous tissue is loose. Thick skin is on the back of the elbow joint, and on its front surface - thin. Above the apex of the ulnar process is the ulnar subcutaneous synovial bag, which, with injuries or prolonged pressure, can be the "object" of the disease (bursitis). In the area of the front surface of the forearm, the skin is thin, mobile, on the back - thicker, its mobility is less. In the palm of the hand, the skin is thick, slow-moving, hairless, subcutaneous tissue has a cellular structure. On the back of the brush the skin is thin, mobile, in the places of the roots of the hair there are sebaceous glands. Subcutaneous fat is loose, which contributes to the formation of edema in inflammatory diseases of the hand.

After dissecting the axillary fascia, the axillary cavity is opened (cavum axillare), shaped like a quadrilateral pyramid, whose apex is directed upward and medially, and the base is downward and lateral. The upper aperture of the axillary cavity, bounded by the clavicle (front), the 1st rib (medially) and the upper edge of the scapula (posterior), connects the axillary cavity with the neck region. Axillary cavity has 4 walls. The anterior wall is formed by fascia-covered large and small pectoral muscles; back - the latissimus muscle of the back, large round and subscapular muscles. The medial wall is represented by the anterior dentate muscle, the lateral by the biceps muscle of the shoulder and the coracoid-brachial muscle.

In the region of the back wall of the axillary cavity between the muscles there are two fairly large slots (holes) covered with loose fiber.

The three-sided opening, located medially, is bounded at the top by the lower edge of the subscapular muscle, from below - by a large round muscle, from the lateral side - by the long head of the triceps muscle of the shoulder. The artery and veins pass through the hole. Surrounding the scapula. The four-sided opening, laterally located, is limited by the surgical neck of the shoulder (laterally), the long head of the triceps brachium (medially), the lower edge of the subscapular muscle (from above) and the large round muscle (from below). Through this hole, the posterior artery and the veins surrounding the humerus and the axillary nerve pass. In the axillary cavity lies a fatty fiber rich loose fibrous connective tissue that surrounds the vessels and nerves (axillary artery and vein, bundles of the brachial plexus and the beginning of the nerves leaving them), as well as axillary lymph nodes.

On the anterior wall of the axillary fossa, 3 triangles are distinguished, within which the topography of the blood vessels and nerves is determined, which are located here. This is the clavicle-thoracic, thoracic and pectoral triangles.

The triangular clavipectorale, directed laterally by the apex, is confined at the top of the clavicle, and at the bottom by the upper edge of the small pectoral muscle. Within it are the axillary artery and vein, the medial bundle of the brachial plexus.

The thoracic triangle (trigonum pecrorale) corresponds to the small pectoral muscle. Here, from the axillary artery, the lateral thoracic artery departs and a long thoracic nerve passes.

In the subgenic triangle (trigonum subpectoral), which is located between the lower edges of the small and large pectoral muscles, there are axillary arteries and vein, as well as the median, musculocutaneous, ulnar and other nerves. In the same triangle from the axillary artery a series of large branches (subscapular, anterior and posterior arteries, circumscribing the humerus) leave.

[1], [2], [3], [4], [5], [6]