Muscles of the upper limbs of man: structure and functions

Upper limbs are an important tool. Due to their presence, people have the ability to perform various movements and actions.

Anatomy of the upper limb

The structure of the structure includes:

• Leather.
• Muscles.
• Bone skeleton.
• Blood vessels.
• Bundles.

This is the anatomy of the upper limb. The right and left arms differ from each other. The size and shape of the brushes vary, for example. The left arm is shorter than the right one, almost half a centimeter. The form that the upper limbs have depends on the profession, age, sex. Of no small importance is the general condition of the organism. The structure of the upper limb is determined by its tasks. It is also due to the peculiarities of the tissue structure. The functions of the upper limbs are quite extensive. Thanks to their actions, people can grab things, write, gesticulate and so on. Next, we will consider what the muscles of the upper limbs are.

Anatomy of musculature

The fibers are divided into two types. The musculature of the shoulder girdle refers to the first, to the second - to the free part. Classification is carried out depending on the tasks performed and the location (at the end of the article a table will be presented). The muscles of the upper limbs in the region of the shoulder girdle are divided into deltoid, supra- and subacute, small and large round, as well as subscapular fibers. The shoulder girdle includes the musculature of the hand, shoulder and forearm.

Large round fibers

They have an oblong flat shape. Begins from the back of the lower corner on the scapula. These muscles of the upper limbs are fixed on a small hillock in the humerus (on the crest). The rear calving is adjacent to the wide back fibers. The large round muscles of the upper limbs, with a contraction, pull the shoulder back, turning it inside. As a result, the hand returns to the trunk.

Deltoid fibers

They are presented in the form of a triangle. Under the lower part of this muscle of the upper limbs are located counterfeit bags. The fibers cover the shoulder joint completely and the musculature of the shoulder locally. The deltoid muscle includes large bundles that converge at the apex. They are divided according to the tasks. The back pulls the arm back, the front ones forward. Fibers begin from the axis of the scapula (lateral end) and part of the clavicle. The fixation site is a deltoid tuberosity in the humerus. The deltoid muscles of the upper limbs divert their shoulders from the outside until they take a horizontal position.

Small round fibers

They make an oblong round muscle. The front part of it is covered with deltoid fibers, the back - with large round ones. The muscle begins from the scapula, slightly below the subacute fibers, to which its upper surface abuts. The segment is attached to the site on the bump of the humerus and the capsule of the joint (to the posterior part). The muscle turns the shoulder outward, pulls back and pulls back the capsule of the joint.

Filament fibers

They form a three-sided muscle. It is located in the subterranean fossa under the trapezoidal segment. The fixation site is the back of the capsule of the shoulder joint and the pad on the large tubercle of the bone. The muscle begins on the surface of the fossa. When the fibers contract, the shoulder rises and the capsule of the joint is pulled back, which prevents pinching.

Sub-fibers

They formed a triangular wide flat muscle. Fibers are located in the subscapular fossa. On the fastening site, there is a tendon bag. The muscle begins on the subscapular fossa, and ends - in a small tubercle in the humerus and on the anterior part of the capsule of the joint. By reducing the fibers, the shoulder rotates inwards.

Subacute fibers

They form a flat triangular muscle. The segment in the subacute is located. The beginning of the fibers is located on its wall and the back of the scapula. It is fixed to the capsule in the shoulder joint and to the middle area on the large tuberosity of the bone, under which is located an incontinent bag. Cutting, the muscle turns the shoulder outward, allows you to withdraw the raised hand, pulls back the capsule of the joint.

Musculature of the shoulder

It is divided into two groups. The front performs flexion, and the rear performs flexion of the shoulder and forearm. The first group includes the double-headed, brachial and beak-like muscles. The second part consists of the triceps and elbow muscles of the upper limbs of man.

Double-headed fibers

They form a spindle-shaped round muscle. In its composition there are two heads: a short one, carrying the hand, and a long, producing lead. The latter starts from the superarticular tubercle of the scapula. The short head departs from the coracoid process. In the place of their connection, the abdomen is formed. It is attached to the tubercle on the radius. In the medial direction there are several fibrous bundles. They form a lamellar process - aponeurosis. Further it passes into the humerus fascia. The tasks of the biceps are the rotation of the forearm and flexion of the forearm at the elbow.

Biliac fibers

They form a flat muscle. It is covered with a short head of the two-headed segment. Biliary muscles of the upper limbs of a person begin at the apex of the eponymous shoulder blade. Fibers are attached below the center of the medial part of the humerus. Due to their reduction, the shoulder rises, hands are led to the median line.

Shoulder fibers

They formed a wide spindle-shaped muscle. Its beginning is the front and outer surfaces of the shoulder bone. Fixation is made to her tubercle and elbow joint capsule. Fibers are completely in the lower humeral part (on the front side) under the biceps muscle.

The ulnar segment

This muscle has a pyramidal shape. Its beginning is the lateral epicondyle of the shoulder bone. Fibers are attached to the back of the ulnar bone body and the eponymous process. Cutting, the muscle extends the forearm. She also coordinates the pulling of the capsule in the elbow joint.

Three-headed fibers

They form a long muscle. It consists of 3 heads: medial, lateral and long. The beginning of the latter is the subarticular scapular tubercle. The lateral head departs from the posterolateral part of the shoulder bone, the medial from the posterior surface. Elements are joined in a spindly abdomen. It subsequently passes into the tendon. An abdominal attachment is made to the joint capsule and elbow process. When the fibers contract, the forearm is unbent, the arm is pulled back and the shoulder is brought to the trunk. The muscle is located from the elbow to the scapula.

Forearm Fibers

They form two groups of muscles: front and back. In each of them there are fibers of a deep and a surface layer. The latter in the front group include wrist flexors (ulnar and radial) and fingers, the humerus segment, round pronator. The department also includes long palmar muscles. In the deep layer there is a square pronator, flexors: a long thumb and a deep finger. The superficial muscles of the posterior group include the elbow, short and long radius extensors of the wrists, finger and little finger. In the deep layer of the department there is a supinator, muscles that divert and unbend the thumb (short and long), extensor for the index finger.

Musculature of the hand

The muscles are located on the palmar surface. Fibers are divided into several groups: middle, medial, lateral. On the back of the surface of the brush are the same-named interosseous muscles. In the lateral group, there are fibers correcting the movements of the thumb: opposing, leading, flexors and retractors. The medial department includes a short palm muscle and a little finger musculature. The latter include a short flexor, leading and retracting fibers. In the middle group there are wormlike, palmar and dorsal interosseous elements.

Table. Muscles of the upper limbs

We hope that the information provided will be useful to you.