Bones of the upper limb of man

The bones of the upper limb and shoulder are referred to the skeleton of the human hand . In anatomy, apart from the bones of the hand, joints and ligaments are also distinguished as their constituent parts. Upper limbs consist of: bones of the shoulder, forearm, arms (wrist, pastern and phalanx of fingers).

Characteristics of the humerus

This limb element is a long tubular bone. It consists of the so-called body and two epiphyses: the upper proximal and the lower distal. The upper part of the shoulder girdle has a rounded shape, and the lower one is triangular. The shoulder joint is a junction of the upper epiphysis with the articular fovea of the scapula. All bones of the skeleton of the upper limbs consist of the body and the epiphyses and are connected to each other.

Structure and function of the ulna

According to the anatomical structure, the elbow and radius bones are referred to the forearm. The ulnar consists of a number of long tubular bones and two ends (proximal and distal epiphysis). The base of the bone is presented in the form of a trihedron, it has certain edges, which bear the following names: anterior (palmar), posterior (dorsal), interosseous (external). The anterior edge of the bone has a circular shape. The rear leaves slightly back. The interosseous edge has a pointed shape and is directed towards the radius bone.

Unlike the distal, the proximal epiphysis is more thickened. Block-shaped cutting, which is in it, is completely covered with articular cartilage. This is necessary in order that the edges of the bone are not erased while the upper limb is constantly moving. At the ends of the block-shaped notch are the processes: coronary and ulnar. The anterior surface of the bone, located below the coronoid process, has a tuberous structure.

The upper and lower epiphyses of the radial and ulnar parts of the arm interact with each other via joints. Any connection of the bones of the upper limbs is a complex mechanism, especially in the area of the elbow. If an injury has occurred and the elbow joint is damaged or the bones are fractured, many operations and operations will be performed by specialists before the elbow can again work.

The lateral side (outer surface) of this element of the upper limb includes a radial notch, a recess for the entry of the radial head. This cavity for the anterior part of the bone and the bone itself form the proximal joint of the forearm.

As well as the lateral side of the distal epiphysis, so in the posteromedial section there is a styloid process, which is necessary for a better ligament of limb elements. We see that it is very difficult to arrange an ulnar bone, which together with the radial bone forms the bones of the upper limb. Human anatomy - the structure of all organs and systems, including bones and joints of its limbs - is not at all elementary.

The radius of the upper limb

The difference of the two components of the forearm is that the distal end of the radius is much thicker than the proximal end. This ending forms a rounded head, in which there is an epiphysis with a flat depression. Thanks to this, the bones are connected correctly. This head is the surface of the joint. On the front side of the radius there is a part that is responsible for attaching the biceps muscle of the shoulder joint. Structural elements of the wrist are connected to the radial bone by means of a massive distal epiphysis. The lower epiphyses of the radial and ulnar bones, joining together, form the radiolucent joint.

Wrist characteristics

The bones of the upper limbs of man consist of short elements arranged in 2 rows (proximal and distal), and have an unusual shape. At the wrist it is presented in the form of a curved groove, the bulge of which is facing the back of the palm.

In the proximal row there are small bones, which were named according to their shape: semilunar, scaphoid, triangular. In addition, here still there is a pea-shaped bone, which adjoins the palmar surface to the trihedral element. The distal row forms a trapezoidal, capitate, and hook-shaped ossicles. To perform their functions, all listed structural components are arranged in such a way that they are not in the same plane. The wrists of the upper extremities of the proximal human person form an ellipsoidal bulge. It connects with the distal epiphysis of the radial part of the upper limb. And in the distal row, the bones are articulated with the metacarpal.

Bones of upper limb

The metacarpal phalanges of the fingers are formed by tubular bones (with one epiphysis), which have a body, base, head. They are curved, facing the convex side towards the back of the brush. The distal row of wrist bones connects with their bases, and the heads - with the beginning of phalanges. The head of the metacarpal bones adjoins the bases of the proximal phalanges, and their head part articulates with the beginning of distal phalanges. Each finger has 3 phalanges: proximal, middle, distal. However, their thumb has only two.

Each phalanx, like all other bones of the upper limbs, the anatomy of which is described above, also has a base, a body and a head. But their peculiarity lies in the fact that they are lined up one after another. In this case, all three phalanges have only one true epiphysis. The proximal parts of the wrist have one pit, in which they connect to the next bone. The middle and distal phalanges differ slightly from the proximal phalanges, since they have two pits to form the joint. These grooves have a flat shape, they are separated by small scallops. Each last phalanx in the finger from above is slightly narrowed, flattened and rough.

Bones of free upper limb, their connection

All bones are joined together by joints, this allows a person to move unlimitedly. The connection of the bones of the upper limbs, clavicle and scapula is represented by the combination of two paired joints: the articulation of the sternal ends of the clavicle with the sternum handle and its acromial ends with the acromion of the scapula. The next bundle of the scapula - the upper transverse, has the form of a short, thin bundle, overlying the scapula of the scapula. A hole for the advancement of nerves and vessels is formed by a transverse sheath with a notch and very often ossifies. In man, the structure of the bones of the upper limbs is very diverse.

The acromioclavicular joint can move in any direction, but the frequency of movements is small. They are hampered by the coracoid-clavicular ligament. It is divided into quadrangular and triangular ligaments. Quadrangular has the form of a trapezoid, and a triangular cone. Both ligaments are located at an angle to each other.

Description of shoulder joint

In the motion of the bone of the upper limb, the shoulder joint plays an important role. The shoulder joint is formed by the head of the humerus and the articular cavity of the shoulder blade. This cavity is oval in shape, occupies one quarter of the head area, slightly concave. The articular lip present in it increases the congruence of the connective tissues covered with hyaline cartilage. The joint capsule has freedom of movement, so when the bone is lowered, it can be folded. It is strengthened by muscles, ligaments, located in the shoulder joint. The head of the shoulder is tightly fixed by muscles and ligaments in the articular cavity. There are no muscles in the anterior-lower part of the shoulder joint. It is surrounded by slimy bags that interact with the joint cavity.

Blood to the shoulder joint approaches through the anterior and posterior arteries located around the shoulder bone. This connection of bones is very mobile, it is characterized by the following actions: rotation, circular movements, extension, bending, retraction, reduction. In humans, the bones of the upper and lower extremities differ slightly, but the joints are the same in structure.

Difficulty of the elbow joint

The joint of the elbow is formed by the connection of the humerus, elbow and radius bones. Inside this large junction there are three small joints:

• Adnate;
• The humerus;
• Ray radiation.

Due to the presence of a joint capsule and a common cavity, they combine into a complex joint covered with hyaline cartilage.

The shoulder and shoulder joints, working together, cause flexion and extension, and the radiation beam participates in the movements of the forearm. Various movements are caused by the presence of a large number of muscles. Such a complex mechanism can not exist without support. And this support in the joint is in the form of an elbow and a radial ligament. They grasp the heads of the bone of the upper limb. The anatomy of a person is arranged in such a way that it prevents the joint from bending in the opposite direction.

How are the bones of the forearm connected?

The radial and ulnar bones are located side by side, and their ends are joined in the joint. Epiphyses of these structures are connected by distal and proximal joints. For the strength of the connection between these bones there is a membrane, which is the beginning of the deep muscles of this part of the upper limbs. The upper joint (proximal) is an integral part of the elbow joint, and the lower one acts independently. The distal radial-fiber junction is separated from the wrist with a small articular disc. It has the form of a triangle with concave plate surfaces.

The structure of the wrist joint

The bones of the wrist are connected to the radius with the help of the joint disc and the surfaces of all the participants in the joint. The proximal rows of the wrist bones are strongly interconnected, so the joint surface is one area from the wrist. It is, of course, smaller than the surface of the radius, so a triangular disc helps to connect two differently sized joint areas. In addition, it helps to separate the elbow from the joint, which is surrounded on all sides by bundles.

What joints are involved in combining the bones of the hand and fingers?

The bones of the hand are joined together by means of three joints:

1. Medium-sized wrist. It is located between the bones of the first and second rows of the wrist. There are many ligaments on the two surfaces of the wrist (palmar and dorsal). This is due to the fact that the hands are actively functioning, they must perform small movements, bend, unbend. This strong ligamentous apparatus is called the radial ligament of the wrist.
2. Wrist-metacarpal. Four metacarpal bones have one capsule and an articular plane. The joint of the thumb is separated from the rest.

The bones of the fingers are joined together by means of metacarpophalangeal and interphalangeal joints. Besides them, there is still a large number of strong ligaments on each finger, which allows a person to bend and unbend fingers. As you can see, the structure of the upper limbs of man is quite complex, but due to this they are distinguished by their mobility.