A human scapula. Anatomy of the human scapula

The system of support and movement, which includes bones, muscles and ligaments, functions in the human body as a whole. The skeleton, formed by a special kind of cells of connective tissue - osteocytes, consists of several sections. It includes a skull, a spine, a thorax, free limbs and belts that ensure the connection of the bones of the upper and lower extremities with the spine.

In this paper, we will focus on the structure of the human scapula, which together with the clavicle forms the belt of the upper limbs. We will also determine its role in the skeleton and get acquainted with the most common pathologies of development.

Features of the structure of flat bones

The supporting apparatus contains several types of bones: tubular, mixed and flat. They differ in appearance and internal anatomical structure. For example, the compact substance of a bone can have the form of two thin plates, between which, like a layer in the cake, there is a spongy tissue, penetrated with capillaries and containing a red bone marrow.

It is this structure that has a sternum, a cranial vault, ribs, pelvic bones and a human scapula. It is the best way to protect the underlying organs: lungs, heart and large blood vessels from mechanical shock and damage. In addition, a large number of muscles are attached to the vast flat surface of the bone with ligaments and tendons, performing static and dynamic work. And the red bone marrow inside the flat bone serves as the main hematopoietic organ supplying the uniform elements: erythrocytes, leukocytes and platelets.

Anatomy of the human scapula

The bone has the shape of a triangle touching the posterior surface of the sternum. Its upper part has a cut edge, the medial region is turned towards the spine, the lateral corner contains the articular cavity. It includes the head of the tubular humerus. Another element of the upper limb belt is the clavicle, it is connected to the scapula using an acromioclavicular joint. The axis passing along the back surface of the scapula reaches the lateral surface, passing into the acromion. On it the place of connection with a clavicle in the form of an articulate surface is located. A more complete picture of the anatomical features of flat bones is provided by the photo of the human scapula presented below.

In embryogenesis, bone is formed from the mesoderm. In a newborn, the ossification of the scapula is not complete and osteocytes are contained only in the body and the aorta, the rest has a cartilaginous structure (an endochondral type of ossification). In the first year of the child's life, ossification points appear in the coracoid process, later in the acromion, the lateral end of the scapula. Complete ossification is completed by the age of 18 years.

How muscles attach to the scapula

The main way to connect bones and muscles in the musculoskeletal system is with the help of tendons.

Due to the collagen fibers, which are the end part of the biceps, to the hillock located above the upper edge of the articular cavity of the scapula, its double head is attached with its long head. The lower edge has the same hummocky surface, to which the muscle, extending the arm in the shoulder joint - triceps (the triceps muscle of the shoulder), joins with the tendon.

Thus, the human scapula takes a direct part in flexing and unbending the upper limb and maintaining the muscular corset of the back. Bones of the upper extremity belt - clavicles and scapulae have a common system of ligaments, but the shoulder has three own ligaments that do not belong to the shoulder and acromioclavicular joints.

The value of the coracoid process

From the upper edge of the scapula departs part of the bone, which is the remainder of the cortex of vertebrates and is called the beak-like process. It is located above the shoulder joint like a visor. To the process with the help of tendons a short head of the biceps, as well as the beak-brachial and small pectoral muscles, is attached.

Coming into the composition of the scapula-the bones of the person directly forming the belt of the upper extremities, the beak-like process participates in the work of the antagonist muscles: biceps and triceps, and its connection with the muscles of the shoulder ensures removal of the upper limb to the sides and upwards. Apparently, the coracoid process is of no small importance in the structure of the scapula. What kind of anatomical origin does he have?

Korakoid and its role in the phylogeny of vertebrates

Earlier we focused on the fact that the upper extremity belt includes paired collarbone and scapula. A person differs from other vertebrates, for example, from birds, reptiles, fish or amphibians, reduction of crow's bone - coracoid. It is associated with the release of the upper limb from physically complex and diverse motor functions in the form of running, flying, swimming or crawling. Therefore, the presence of a third bone in the belt of the forelimbs has become inexpedient. Crow bone from a man was reduced, only a part of it remained - a beak-shaped process that became part of the scapula.

Pathology of the bones of the upper extremity belt

The most common anomalies in the structure of the human scapula occurred as a result of both organogenesis disorders during the intrauterine development period and in the form of complications after dystrophic muscle injury or neuroinfections. These include, for example, the syndrome of the pterygoid scapula, which is determined by both external examination of the patient and on the roentgenogram.

The disease is accompanied by debilitating pain in the shoulder and behind the sternum as a result of rapidly developing neuropathy. Remission occurs when medical and prophylactic measures are observed: dosed physical activity, massage, special exercises for the muscles of the shoulder and back.

Another pathology is the congenital high standing of the shoulder blade (Sprengel's disease). This anomaly is combined with a violation of the structure of the vertebrae, anatomical defects of the ribs, for example, their fusion or partial absence. There are two forms of the disease: one- and two-sided symmetry breaking of the scapula.

So, with bilateral lesion, the left scapula is located higher than the right one. Anomaly is dangerous by the degeneration of myocytes in the basic muscles: trapezoid and rhomboid - large and small. A positive prognosis can be expected from a surgical intervention performed by a child under 8 years of age, at a later age they do not resort to surgery because of the high risk of complications, limited to therapeutic gymnastics and massage.