The structure of the human shoulder blade. Scapular region Scapula structure anatomy in Latin and Russian

The musculoskeletal system consists of bones, joints, ligaments and muscle tissue. Together they work as a single system. The skeleton includes various sections. Among them are: the skull, belts with attached limbs.

The shoulder blade is an element of the upper belt. In the article we will take a detailed look at the structure, adjacent parts and functions of this bone.

The human skeleton consists of different types of bones: flat, tubular and mixed. They differ from each other in shape, structure and function.

The scapula is a flat bone. The peculiarities of its structure are such that inside there is a compact substance of two parts. Between them lies a spongy layer with bone marrow. This type of bone provides reliable protection for internal organs. In addition, many muscles are attached to their flat surface with the help of ligaments.

Human Scapula Anatomy

What is a scapula? This is a component of the upper limb belt. These bones provide the connection of the humerus with the clavicle; their external shape is triangular.

It has two surfaces:

• anterior costal;
• dorsal, in which the spine of the scapula is located.

The spine is a protruding ridge-like element passing through the dorsal plane. It rises from the median edge to the lateral angle and ends at the acromion of the scapula.

Interesting. The acromion is a bony element that forms the highest point in the shoulder joint. Its process is triangular in shape and becomes flatter towards the end. Located on top of the glenoid cavity, to which the deltoid muscles are attached.

There are three edges in the bone:

• the upper one with a hole for vessels with nerves;
• middle (medial). The edge lies closest to the spine, otherwise called the vertebral;
• axillary - wider than the others. It is formed by small bumps on the superficial muscle.

Among other things, the following scapula angles are distinguished:

acromion process

• upper;
• lateral;
• lower.

The lateral angle is located separately from the other elements. This occurs due to a narrowing in the bone - the neck.

The coracoid process lies in the space between the neck and the recess from the upper edge. It was given its name by analogy with the beak of a bird.

The photo shows the acromion process.

Ligaments

The parts of the shoulder joint are connected by ligaments. There are three in total:

1. Coracoacromial ligament. It is formed in the form of a plate, shaped like a triangle. It extends from the anterior apex of the acromion to the coracoid process. This ligament forms the arch of the shoulder joint.
2. Transverse scapular ligament, is located on the dorsal surface. It serves to connect the glenoid cavity and the body of the acromion.
3. superior transverse ligament, connecting the edges of the tenderloin. Represents a bundle, ossifies if necessary.

Muscles

The pectoralis minor muscle, necessary for moving the scapula both downward and forward or to the side, is also attached to the coracoid process, as well as a short element of the biceps.

The long element of the biceps is attached to a convexity located above the glenoid cavity. The biceps muscle is responsible for flexing the shoulder at the joint and the forearm at the elbow. The coracoid brachialis muscle is also attached to the process. It is connected to the shoulder and is responsible for its elevation and small rotational movements.

The deltoid muscle is attached to the protruding part of the acromion and clavicular bone at its base. It covers the coracoid process and is attached to the humerus with its sharp part.

The muscles of the same name are attached to the subscapularis, supraspinatus, and infraspinatus fossa. The main function of these muscles is to support the shoulder joint, which has an insufficient number of ligaments.

Nerves

There are three types of nerves running through the scapula:

• suprascapular;
• subscapular;
• dorsal.

The first type of nerve is located along with blood vessels.

The subscapular nerve carries nerves to the muscles of the back (located under the shoulder blade). It innervates the bone and adjacent muscles, thereby providing communication with the central nervous system.

Functions of the scapula

The scapula bone performs a number of functions in the human body:

• protective;
• connecting;
• supportive;
• motor.

Let's clarify where the shoulder blades are. They act as a connecting element of the shoulder girdle with the upper limbs and sternum.

One of the main functions is to support the shoulder joint. This occurs thanks to the muscles extending from the shoulder blades.

Two processes, the coracoid and the acromion, protect the top of the joint. Together with muscle fibers and numerous ligaments, the scapula protects the lungs and aorta.

The motor activity of the upper belt directly depends on the scapula. It helps with rotation, shoulder abduction and adduction, and arm elevation. When the shoulder blade is injured, the mobility of the shoulder girdle is impaired.

Detailed structure of the scapula bone in the photo.

Conclusion

A wide, paired bone called the scapula is an important component of the human shoulder girdle. Thanks to its shape, it performs many functions, including protective. In addition, it ensures full functioning of the upper girdle - in particular, the shoulder joint.

The scapula is surrounded on all sides by muscles that strengthen and move the shoulder. It acts only thanks to the pectoral and dorsal muscles.

The girdle of the upper limb (cingulum membri superioris) is formed by the paired bones of the clavicle (clavicula) (Fig. 20, 21) and the scapula (scapula) (Fig. 20, 22).

The clavicle is a long, S-shaped tubular bone. The upper surface of the body of the clavicle (corpus claviculae) is smooth, and the lower one has roughness, to which the ligaments connecting the clavicle with the coracoid process of the scapula and with the 1st rib are attached (Fig. 21). The end of the clavicle, connecting to the manubrium of the sternum, is called the sternal (extremitas sternalis), and the opposite, connecting to the scapula, is called the acromial (extremitas acromialis) (Fig. 21). At the sternal end, the body of the clavicle is convexly facing forward, and at the acromial end, convexly facing backward.

The scapula is a flat, triangular-shaped bone, slightly curved backward. The anterior (concave) surface of the scapula is adjacent at the level of the II-VII ribs to the posterior surface of the chest, forming the subscapular fossa (fossa subscapularis) (Fig. 22). The muscle of the same name is attached to the subscapular fossa. The vertical medial edge of the scapula (margo medialis) (Fig. 22) faces the spine. The horizontal upper edge of the scapula (margo superior) (Fig. 22) has a notch of the scapula (incisura scapulae) (Fig. 22), through which the short superior transverse scapula ligament passes. The lateral angle of the scapula, with which the upper epiphysis of the humerus articulates, ends in a shallow articular cavity (cavitas glenoidalis) (Fig. 22), which has an oval shape. Along the anterior surface, the glenoid cavity is separated from the subscapular fossa by the neck of the scapula (collum scapulae) (Fig. 22). Above the neck, a curved coracoid process (processus coracoideus) extends from the upper edge of the scapula (Fig. 22), protruding above the shoulder joint in front.

Along the back surface of the scapula, almost parallel to its upper edge, runs a relatively high ridge called the spine of the scapula (spina scapulae) (Fig. 22). Above the shoulder joint, the spine forms a wide process - the acromion (Fig. 22), which protects the joint from above and behind.

Between the acromion and the coracoid process runs a wide coracoacromial ligament, which protects the shoulder joint from above. The recesses on the posterior surface of the scapula, located above and below the spine, are called the supraspinatus and infraspinatus fossae, respectively, and contain the muscles of the same name.

The support and movement system, which includes bones, muscles and ligaments, functions in the human body as a single whole. The skeleton, formed by a special type of connective tissue cells - osteocytes, consists of several sections. It includes the skull, spine, free limbs and girdles that connect the bones of the upper and lower limbs to the spine.

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

Features of the structure of flat bones

The support apparatus contains several types, mixed and flat. They differ from each other both in appearance and internal anatomical structure. For example, compact bone substance may have the form of two thin plates, between which, like a layer in a cake, there is spongy tissue, penetrated by capillaries and containing red bone marrow.

This is the structure of the human sternum, cranial vault, ribs, pelvic bones and scapula. It best helps protect underlying organs: lungs, heart and large blood vessels from mechanical shock and damage. In addition, a large number of muscles that perform static and dynamic work are attached to the extensive flat surface of the bone by ligaments and tendons. And the red bone marrow, located inside the flat bone, serves as the main hematopoietic organ that supplies formed elements: red blood cells, white blood cells and platelets.

Human Scapula Anatomy

The bone is shaped like a triangle, touching the back of the sternum. Its upper part has a cut out edge, the medial section is turned towards the spine, the lateral angle contains the glenoid cavity. It includes the head of the tubular humerus. Another element of the upper limb girdle, the clavicle, is connected to the scapula using the acromioclavicular joint. The axis passing along the posterior surface of the scapula reaches the lateral surface, passing into the acromion. It contains the junction with the collarbone in the form of an articular surface. A more complete picture of the anatomical features of flat bones is given by the photo of a human scapula presented below.

During embryogenesis, bone is formed from mesoderm. In a newborn, the ossification of the scapula is not complete and osteocytes are contained only in the body and spine, the rest has a cartilaginous structure (enchondral type of ossification). In the first year of a 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 shoulder blade

The main way bones and muscles are connected in the musculoskeletal system is through tendons.

Thanks to the collagen fibers, which are the end part of the biceps, the biceps brachii muscle is attached to the tubercle located above the upper edge of the glenoid cavity of the scapula with its long head. The lower edge has the same tuberous surface, to which the muscle that extends the arm at the shoulder joint, the triceps (triceps brachii muscle), is attached with the help of a tendon.

Thus, the human scapula is directly involved in flexion and extension of the upper limb and maintaining the muscular corset of the back. The bones of the upper limb girdle - the clavicle and scapula - have a common system of ligaments, but the scapula has three of its own ligaments that are not related to the shoulder and acromioclavicular joints.

The meaning of the coracoid process

A part of the bone extends from the upper edge of the scapula, which is a remnant of the coracoid of vertebrates and is called the coracoid process. It is located above the shoulder joint like a visor. The short head of the biceps, as well as the coracobrachialis and pectoralis minor muscles are attached to the process with the help of tendons.

Being part of the scapula, a human bone that directly forms the girdle of the upper limbs, the coracoid process participates in the work of the antagonist muscles: biceps and triceps, and its connection with the muscles of the shoulder ensures abduction of the upper limb to the sides and upwards. As you can see, the coracoid process is of no small importance in the structure of the scapula. What anatomical origin does it have?

Coracoid and its role in the phylogenesis of vertebrates

Previously, we focused on the fact that the girdle of the upper limbs includes the paired clavicle and scapula. Humans are distinguished from other vertebrates, for example, from birds, reptiles, fish or amphibians, by the reduction of the crow bone - the coracoid. It is associated with the release of the upper limb from physically complex and varied motor functions such as running, flying, swimming or crawling. Therefore, the presence of a third bone in the girdle of the forelimbs became impractical. The crow bone in humans was reduced, only part of it was preserved - the coracoid process, which became part of the scapula.

Pathologies of the bones of the upper limb girdle

The most common anomalies in the structure of the human scapula arose as a result of both a violation of organogenesis during the period of intrauterine development, and as complications after degenerative muscle damage or neuroinfections. These include, for example, a syndrome that is determined both during an external examination of the patient and on an x-ray.

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

Another pathology is congenital high scapula (Sprengel 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: unilateral and bilateral violation of the symmetry of the shoulder blades.

So, with a bilateral lesion, the left shoulder blade is located higher than the right. The anomaly is dangerous due to the degeneration of myocytes into basic and rhomboid - large and small. A positive prognosis can be expected from surgery performed on a child under 8 years of age; at a later age, surgery is not used due to the high risk of complications, and is limited to therapeutic exercises and massage.

The human scapula is a wide and flat paired bone behind the chest, which is the basis of the shoulder girdle and has the appearance of a bayonet shovel, pointing downwards. The wide part of the shoulder blade is located in the area of ​​the shoulder girdle (which in everyday life is not quite correctly called the shoulder).

Anatomy

The lateral (outer) edge of the scapula is thickened; in its upper corner there is an articular cavity, which with the head of the humerus forms the shoulder joint (the shoulder is the upper part of the arm: from the same shoulder joint to the elbow). The shoulder joint is one of the most mobile joints of the human skeleton.

There, next to the articular cavity, there are two bony protrusions - the acromion directed backwards and the coracoid process protruding forward. Articulated with the acromion at the acromioclavicular joint is the clavicle, the bone that connects the scapula to the sternum.

The coracoid process does not articulate with the bones - muscles are attached to it: the pectoralis minor, which is responsible for moving the scapula down, forward and towards its inner lateral edge, as well as the biceps (with its short head). The long head of the biceps is attached to a tubercle located above the glenoid cavity of the scapula. The biceps (biceps muscle) is responsible for flexing the shoulder at the shoulder joint and the forearm (the lower part of the arm - from the elbow to the wrist) at the elbow. Also attached to the coracoid process is the coracoid brachialis muscle, which is connected to the shoulder and is responsible for its elevation and minor rotational movements.

The anterior plane of the scapula, facing the ribs, is slightly concave; it is called the subscapular fossa. The posterior surface is convex, it is divided into two unequal parts by a bony protrusion running horizontally - the spine (ridge). The ridge originates from the inner edge of the scapula, rises higher and, approaching the outer edge, passes into the acromion.

The deltoid muscle, which has the shape of a triangle, is attached to the crest, the outer part of the acromion and half of the clavicular bone. It completely covers the coracoid process and the shoulder joint, and its tip is attached to the humerus. This muscle forms the upper part of the shoulder and is involved in abduction of the shoulder joint.

The smaller - upper - part of the scapula above the crest is called the supraspinatus fossa, the lower, respectively, the infraspinatus. The muscles of the same name are attached to the subscapularis, supraspinatus and infraspinatus fossa

The main function of the subscapularis, supraspinatus and infraspinatus muscles is to hold the shoulder joint, which is poor in its own ligamentous apparatus. The same purpose is used for another muscle – the teres minor, attached to the upper part of the outer edge of the scapula.

In general, the scapula is almost completely enveloped on both sides by muscles responsible only for the shoulder - its fixation and mobility. The scapula itself moves only thanks to the dorsal and pectoral muscles.

Functions of the scapula

Main functions of the scapula:

The shoulder blades are the main link between the shoulder girdle and the arms and sternum.

The processes of the scapula - the coracoid and acromion - as well as their ligamentous apparatus protect the shoulder joint from above. In addition, the shoulder blade bones with their muscles and ligaments, along with the ribs and back muscles, protect the lungs and aorta.

Part of the muscles extending from the shoulder blades strengthens and holds the shoulder joint.

The shoulder blades are involved in the movement of the entire shoulder girdle and arms - performing rotational movements in the shoulder joint, raising the arm, abducting and adducting the shoulder. This participation can be either indirect: with the help of the muscles responsible for the movement of the shoulder, attached to the scapula, or direct: for example, abduction of the shoulder, starting from a certain angle, is possible only when the scapula is rotated. If the scapula is damaged, the mobility of the shoulder girdle is sharply limited and the ability to work is lost.

Diseases and injuries of the scapular region

The scapula bones and joints can be subject to injury and inflammatory processes. There are also malformations of the shoulder blades. The shoulder blades may be in an incorrect position due to spinal deformities. In addition, pain in the scapular region does not always indicate disease of the shoulder blades in particular and the shoulder girdle in general.

Fractures

Scapula fractures usually occur as a result of a strong blow from the rear or front. There are intra-articular (involving the glenoid cavity) and extra-articular (any area without damage to the glenoid cavity) fractures.

Scapula fractures may be accompanied by the following symptoms:

For intra-articular fractures, surgery is most often required - osteosynthesis, which includes comparison and fixation of bone fragments. Fractures of the body of the scapula usually heal on their own without complications, provided there is complete rest. Depending on the fracture, the patient’s arm, bent at the elbow, is fixed to the chest on the affected side or, conversely, taken to the side using a special splint. Fixation lasts about a month, after which the arm in the shoulder joint is gradually developed.

The scapula is designed in such a way that significant external force is required to fracture it. In addition, vital organs are in close proximity - the heart, lungs, and great vessels. Therefore, if you suspect a fracture of the scapula, you should consult a doctor as soon as possible.

Dislocation

Scapula dislocations are extremely rare. Their cause is a strong tug on the arm, as a result of which the shoulder blade rotates and moves outward, and its lower edge is compressed between the ribs. This causes stretching and tearing of the muscles attached to the shoulder blade and spine.

Symptoms:

• the scapula is in an abnormal position - its outer lateral edge is sharply protruded;
• any movement in the shoulder joint causes severe pain.

The dislocation is reduced by a surgeon under local anesthesia, after which the arm is fixed to the torso for two to three weeks.

Bursitis

Bursitis of the shoulder blade refers to inflammation of the periarticular bursae of the shoulder joint. The cause of the disease can be injury, infection, or an autoimmune reaction.

Symptoms:

Bursitis is treated with conservative methods - antibiotic therapy, painkillers, physical therapy - under the supervision of a doctor.

Developmental defects

Examples of congenital anomalies of the scapula:

• aplasia (absence) and hypoplasia (underdevelopment);
• pterygoid scapula;

Aplasia is most often combined with the absence of an arm on the same side.

The pterygoid scapula is not only a cosmetic defect - a protruding inner edge, but also a functional disorder - the inability to rotate the arm and raise it. The disease is treated promptly.

Sprengel's disease is characterized by an abnormally high position of the scapula (scapulae), often by impaired development of the muscles of the shoulder girdle, and is also often combined with other anomalies. Complaints: cosmetic defect and difficulty in shoulder abduction. In mild cases, physiotherapy is prescribed; in more severe cases, surgery is prescribed.

Protruding blades

Shoulder blades can “stick out” in both children and adults for various reasons, including:

Depending on the cause, protrusion of the shoulder blades may not bring suffering other than moral, or be accompanied by disorders that significantly reduce the quality of life.

Poor posture can be corrected quite easily with the help of exercises, massage, and developing the habit of keeping your back straight. In other cases, it is necessary to treat the underlying disease.

Pain in the shoulder blades

Pain in the scapula may indicate damage to the scapula itself, its joints or the musculo-ligamentous apparatus, as well as diseases of the internal organs, in which the pain often “radiates” to the scapular region.

So, pain under the left shoulder blade may be accompanied by:

• heart diseases – coronary heart disease (angina, heart attack), myocarditis;
• lung diseases;
• stomach diseases;
• aortic aneurysm dissection;
• pancreatic diseases.

Pain in the area of ​​the right shoulder blade is caused by:

• diseases of the biliary system and liver parenchyma (sometimes pain can radiate to the left shoulder blade);
• malignant breast tumors.

Pain in the area of ​​any shoulder blade can be accompanied by complicated osteochondrosis and neuralgia.

The scapula belongs to the scapular-brachial section of the spine. In the context of the anatomical structure, the human scapula is a paired bone with a triangular shape. It is located on the back with the base up and the sharp end down, on both sides of the spinal column. The bone itself is wide and flat, slightly curved backwards.

Anatomical structure

The scapula has the following structure at the back:

• spine (protruding surface that crosses one-fourth of the scapula);
• acromion (outer end of the scapula);
• coracoid process (named for its resemblance to a bird's beak);
• neck;
• body;
• inner edge;
• outer corner.

Front structure:

• body;
• glenoid cavity;
• coracoid process.

The blade has two surfaces:

• concave anterior;
• convex back.

The concave anterior surface is a small depression where the scapular muscle is attached, and the convex posterior surface is the spine of the scapula. The scapular spine is a protruding surface that crosses one-fourth of the scapula.

Has three edges:

• the upper one, in which there is an opening for the passage of nerve fibers and blood vessels;
• vertebral (medial) is called so because it is closest to the spine;
• axillary (lateral) - the most massive area, which is formed by tubercles on the brachial muscle.

And also three angles:

• upper (medial), slightly rounded and facing upward;
• the lower corner, which is thicker in structure than the upper;
• lateral opposite to superior medial.

The lateral angle is isolated from the main bone by a small restriction called the neck. But between the neck and the upper edge there is a coracoid process.

Functions of the scapula

Its function is to ensure mobility of the upper limb by connecting the humerus and clavicle into one common movable complex.

The following functions are also distinguished:

• protective;
• binder;
• strengthening;
• motor.

The protective function is that vital organs, veins and arteries are in close proximity.

The motor function, together with the muscle groups that are attached to the scapula, are capable of performing various movements of the limb. The range of these movements is quite wide:

• rotation by hand;
• abduction of the arm to the side, back and forth;
• raising your hands up.

If the scapula is damaged, quality of life and loss of performance are reduced.

Injuries, damage and pathologies

Damage to this anatomical segment occurs for the following reasons:

• falling from a height onto your back;
• blow to the back;
• falling on the shoulder and arm;
• road and transport accidents;
• injuries at work.

In this case, injuries can be of a closed or open type. With closed injuries, there is no violation of the integrity of the skin. Open - occur as a result of skin rupture and the appearance of a wound surface.

Fractures are of the following types:

• in the cervical area;
• in the area of ​​the glenoid cavity;
• in the axis area;
• damage to the coracoid process;
• injuries of the acromion process;
• injuries in the upper and lower corners;
• longitudinal and transverse fractures;
• comminuted fractures;
• damage from a bullet wound or impact with a sharp object (perforated).

Of all the injuries listed, the most common are injuries to the glenoid cavity and acromion. And the most difficult injury is a fracture of the neck of the scapula, which has serious complications and consequences.

Fractures

Symptoms include severe pain in the shoulder and forearm, which becomes unbearable when trying to move the limb. Swelling is observed and hematomas are formed. Pathological mobility. With a crack, the above symptoms are not observed.

Traumatization of this area has one characteristic symptom - Comolli's triangle. What is the essence of the phenomenon? It appears as a triangular swelling. When you try to touch the area of ​​injury, the pain becomes more pronounced. And with a displaced fracture, an acoustic phenomenon appears - crepitation of fragments.

In some cases, the following symptom is observed: the shoulder and limb rise. This suggests that the pearl occurred in the joint area. In the part of the elevation, blood accumulates in the joint cavity, so the shoulder increases in size. When the neck is fractured, the shoulder, on the contrary, goes down (hangs), when the acromial process is injured, it protrudes forward, and when the coracoid process is damaged, it deepens.

An open fracture, in which bone fragments are visible and an open wound has occurred, can become infected. Also in this case, blood vessels and nerve endings are damaged.

Fractures happen:

• intra-articular, when the joint is involved;
• extra-articular, as a rule, there is trauma to any area, but without involving the joint in the pathological process.

Intra-articular injuries require surgical treatment to compare and restore bone fragments. Fractures of the body of the scapula usually heal well provided strict bed rest is observed. To do this, the arm bent at the elbow is fixed to the torso with a special splint. The duration of wearing the splint is approximately a month. After which physiotherapeutic procedures, massage and development of the shoulder joint are prescribed.

Dislocation

Such damage is extremely rare. It develops due to a strong jerk of the arm or shoulder to the side, resulting in displacement of the scapula. In this case, the characteristic manifestation is its protrusion and severe pain, especially when trying to move the arm. The dislocation is reduced by a qualified specialist, only in a medical facility and only under anesthesia. Then immobilization is carried out, fixing the arm to the body for 15 days.

Bursitis

This is an inflammatory disease that manifests itself as damage to the periarticular bursae of the shoulder joint. The cause of the disease is most often an infection of both an endogenous and exogenous nature. It can also occur as a result of injury and an autoimmune process. Manifested by the following symptoms:

• pain in the area of ​​the affected joint;
• swelling and redness of the skin;
• feeling of numbness;
• limitation of mobility.

Treatment is carried out conservatively. The following drugs are prescribed:

• nonsteroidal drugs (NSAIDs);
• steroid hormones;
• antibiotics (for infectious etiology of the disease);
• analgesics;
• chondroprotectors;
• vitamin and mineral complexes.

Developmental defects

Protruding shoulder blades are considered developmental defects. Most often they are congenital, but can also appear as a result of spinal curvature as a result of incorrect back position for a long time. Such damage includes:

• poor posture;
• kyphosis and scoliosis;
• muscle rupture or paralysis.

Most often, their protrusion does not cause pain, but is considered a cosmetic flaw or defect. After all, it seems that the person has grown a hump. Therefore, this causes him to feel inferior and suffer morally, which significantly affects the quality of a person’s life. Currently, such defects can be corrected with the help of physical therapy and massage.