Human skeleton: structure. Skeleton of a human hand

The human skeleton can be divided into 4 sections. The upper is the belt of the upper limb. This includes a scapula and collarbone. Next is the anatomical arm itself, that is, the humeral bone section. The next section is the forearm, consisting of the elbow and radius. The last one is the bone of the brush. The skeleton of the left hand is a mirror image of the right skeleton.

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Consider the skeleton of the hand for each section. The scapula and collarbone are joined together, and the ball joint joins them with the humerus. But not only the humerus joins them. They serve as a place of attachment for the muscles that are responsible for the movement of the hand.

Next comes the humerus directly. To her through the elbow joint is fastened radial and ulnar. The latter are mobile relative to each other. With the position of the hand, when the palm looks inward, these bones are parallel, but it is necessary to turn the palm forward, as they shift and cross.

The skeleton of the hand is the most complex. The structure includes 27 bones. These elements are further divided into several groups: the wrist, the pastern and the phalanges of the fingers, which are connected through the interphalangeal joints. It is the complexity of this device and allows the hands to be so versatile and skilful. With its help, you can do rough work with mechanical operations, but it also allows you to perform fine precise movements.

Detailed structure of the shoulder girdle

The skeleton of the arm in the shoulder girdle is represented by a scapula and clavicle. It is the area of their placement and connection with the humerus and is called the shoulder in everyday life. However, the humerus is an anatomical shoulder, and these elements constitute the belt of the upper limb. But, considering the skeleton of the human hand, the structure should be studied together with the shoulder belt, which significantly affects the functionality.

Scapula

The scapula is a flat bone from the back. Has a triangular shape with the upper, lateral and medial margins and the lower, upper and lateral angles. It is the thickened lateral corner that is provided with the articular cavity where the articulation of the scapula with the head located in the next section of the humerus occurs. A little above the cavity is the neck of the scapula, which looks like a narrowed place. The articular cavity is also surrounded by tubercles - subarticular and superarticulate.

The scapula itself has a somewhat concave surface - a subscapular fossa - in the region of the ribs from the side of the thorax. But on the back surface there is an awn that runs along the shoulder from the inner edge to the outer corner. On the sides of the awn, the supraspinous and subacute fossa is identified, where the muscles with the same names are attached. Outwardly, this awn passes into the shoulder process located above the shoulder joint , called the acromion. Another scapula is equipped with a beak-like process, facing forward and serving to fasten ligaments and muscles.

Collarbone

The clavicle is a tubular bone, curved S-shaped. Has a horizontal position, goes in the upper front of the chest near the neck. The medial sternal end is attached to the sternum, and the acromial lateral connects to the scapula. Also fastening is made by muscles and ligaments, which causes the presence of a roughness on the lower surface, namely the line and the tubercle.

The structure of the shoulder

Behind the shoulder belt goes directly to the skeleton of the human hand. The shoulder is formed by the humerus bone. It is a tubular bone, rounded in cross section from the upper side and triangular closer to the bottom. The upper end is crowned with a hemispherical head that is facing towards the scapula. The head has an articular surface. Slightly below is the anatomical neck of the bone and two tubercles for fixing the muscles. On the outside, a large tubercle is turned, and a small one comes to the front. From each the ridge goes down, but between it and the tubercles there is a furrow for the passage of the tendon. The narrowest part of the bone was called the surgical neck.

The body of the bone is called the diaphyseal. The deltoid tuberosity on its outer surface is designed to hold the deltoid muscle. And the posterior surface is decorated with a furrow of the radial nerve, which runs slightly along a spiral.

The distal epiphysis is the inferior end of this bone. Here the condyle and articular surface is formed, with which the bone connects to the next section. The humerus block is the medial part of the joint that joins the ulnar bone. The lateral part of the spherical form - the head of the condyle - connects with the radius bone. Two pits are provided above the block, where the processes of the ulnar bone go with the movements of the hand, they are called the pits of the coronoid and the elbow process. Also, near the distal end there are epicondyle (lateral and medial), where ligaments and muscles are attached.

Structure of the elbow and forearm

The forearm is the site of the limb from the elbow to the wrist. In everyday life this part was often called an elbow, including used as a measure. The elbow and radial bones of the forearm and the humerus itself enter the elbow joint. The skeleton of the arm of this department is represented by the ulna and radius bone. They are interconnected among themselves: the radial one can rotate around the elbow during movement of the hand. Due to this, the brush can be rotated up to 180º.

Elbow bone

The elbow is triangular in shape. The upper end is thickened, provided with a block-shaped notch in front, to be joined to the humerus. The lateral edge ends with a radial notch, which is needed to connect the head of the second bone of the forearm - the radial. The coronal anterior process and the ulnar posterior go along both sides of the block-shaped notch. Under the anterior process there is tuberosity for fastening the brachial muscle. The head is located on the distal lower end of this bone. The articular surface on its radial side serves to articulate with the radial bone. The head of the ulna is also provided with a subulate appendage on the posterior margin.

Radius

The radius of the arm was thickened at the lower end, and not on the upper end, as in the ulnar. On the upper side is the head of the radius, which allows you to connect with the humerus. The upper surface of the head has a pit, which is necessary for articulation from the head of the condyle located on the humerus bone. The articular circumference along the edge of the head allows to connect with the ulna. The head narrows downward, passing into the neck of the radius. On the inner side just below the cervix, tuberosity allows the attachment of the biceps arm muscle to the tendon.

The lower end of this bone is equipped with a carpal articular surface, which connects this department with a brush. There is also a styloid process, turned to the outside, and on the inner side there is an elbow notch, intended for articulation with the corresponding head of the ulna. Also, the skeleton of the hand in this place contains a limited interosseous space enclosed between the sharp edges of the bones of the forearm.

Wrist

The skeleton of the human hand is divided into the wrist, the pastern and the fingers. Each department is made up of a number of bones and moving joints. This structure allows you to perform various actions by hands, deftly and quickly to work even with small details.

Wrist

The skeleton of the hand starts with the wrist. There are eight bones at once, small in size and irregular in shape. These are spongy bones. They are arranged in two rows. Here, the pea, trihedral, semilunar and navicular bones of one row are distinguished, and the second is hook-shaped, capitate, trapezoidal and polygonal. The first proximal row serves as the articular surface necessary for articulation with the radius. The second row is distal, connected to the first joint of irregular shape.

Located in different planes, the bones of the wrist form a so-called groove of the wrist from the side of the palm, and on the back side there is a bulge. From the furrow of the wrist are the tendons, which are responsible for the work of flexor muscles.

Pastern

The pastern is formed by five metacarpal bones. These are tubular bones consisting of the body, the base and the head. The skeleton of the human hand is distinguished by the great opposition of the thumb to the rest and its best development, which greatly increases the possibilities of the limb. To the big finger there is a shorter, but more massive bone. The bases of these bones are connected with the bones of the wrist. The articular surfaces in this case for the outer fingers have a saddle shape, and the remaining ones are articular surfaces of a flat type. The head of the hemispherical articular surface connects metacarpal bones with phalanges.

Fingers

The bones of the fingers consist of two or three phalanges: the first consists of two, and the rest consists of three. The length of the phalanges decreases as you move away from the pastern. Each phalanx consists of three parts: a body with a base and a head at the ends. Phalanges end with articular surfaces at both ends, which is due to the need for an articular joint with further bones.

Between the proximal phalanx and the metacarpal bone of the large (first) finger there are still sesamoid bones hidden by the tendons. It is worth noting that sometimes there is an individual structure of the hand: the skeleton of the brush can be supplemented with other elements. Sesamoid bones can also be in a similar place near the second and fifth fingers. These elements (as well as bone processes) are attached to the muscles.