The upper limbs are an important working tool. Due to their presence, people have the ability to perform various movements and actions.
Anatomy of the upper limb
The structure includes:
- Leather.
- Muscles.
- Bone skeleton.
- Blood vessels.
- Bundles.
Such is the anatomy of the upper limb. The right and left hand are different from each other. Different sizes and shapes of brushes, for example. The left hand is shorter than the right by almost half a centimeter. The shape that the upper limbs have depends on the profession, age, gender. The general condition of the body is also important. The structure of the upper limb is determined by its tasks. It is also due to the peculiarities of the structure of tissues. The functions of the upper limbs are quite extensive. Thanks to their actions, people can grab objects, write, gesticulate, and so on. Next, consider what the muscles of the upper limbs are.
Muscular Anatomy
Fibersdivided into two types. The first includes the muscles of the shoulder girdle, the second - the free part. The classification is carried out depending on the tasks performed and the location (a table will be presented at the end of the article). The muscles of the upper limbs in the region of the shoulder girdle are divided into deltoid, supra- and infraspinatus, small and large round, as well as subscapular fibers. The composition of the shoulder girdle includes the muscles of the hand, shoulder and forearm.
Large round fibers
They have an oblong flat shape. Start from the back of the lower angle on the shoulder blade. These muscles of the upper limbs are fixed on a small tubercle in the humerus (on the crest). The posterior calving is adjacent to the broad fibers of the back. The large round muscles of the upper limbs, when contracted, pull the shoulder back, turning it inward. As a result, the arm returns to the body.
Deltoid fibers
They are presented in the shape of a triangle. Under the lower part of this muscle of the upper limbs are subdeltoid bags. The fibers cover the shoulder joint completely and the muscles of the shoulder locally. The deltoid muscle includes large bundles converging at the top. They are divided according to tasks. The rear ones pull the hand back, the front ones forward.
Fibers start from the axis of the scapula (lateral end) and part of the clavicle. The site of fixation is the deltoid tuberosity in the humerus. The deltoid muscles of the upper limbs abduct the shoulders outward until they assume a horizontal position.
Small roundfibers
They make up an oblong rounded muscle. Its anterior part is covered by deltoid fibers, the posterior part by large round ones. The muscle starts from the scapula, slightly below the infraspinatus fibers, to which its upper surface adjoins. The segment is attached to the platform on the tubercle of the humerus and the joint capsule (to its back). The muscle turns the shoulder outward, retracts and retracts the joint capsule.
Supraspinatus fibers
They form a trihedral muscle. It is located in the supraspinatus fossa under the trapezoidal segment. The place of fixation is the posterior part of the shoulder joint capsule and the platform on the large tubercle of the bone. The muscle begins on the surface of the fossa. The contraction of the fibers lifts the shoulder and retracts the joint capsule, which prevents pinching.
Subscapular fibers
They formed a triangular wide flat muscle. The fibers are located in the subscapular fossa. At the attachment site there is a tendon bag. The muscle begins on the subscapular fossa, and ends in the small tubercle in the humerus and on the front of the joint capsule. Due to the contraction of the fibers, the shoulder rotates inward.
Infraspinatus fibers
They form a flat triangular muscle. The segment is located in the infraspinatus fossa. The beginning of the fibers is located on its wall and the posterior scapular part. It is fixed to the capsule in the shoulder joint and to the middle area on the large tuberosity of the bone, under which the tendon bag is located. Contracting, the muscle rotates the shoulderoutward, allows you to remove the raised hand, delays the joint capsule.
Musculature of the shoulder
It is divided into two groups. The anterior one performs flexion, and the posterior one performs extension of the shoulder and forearm. The first group includes the biceps, shoulder and coracoid muscles. The composition of the second section includes the triceps and ulnar muscles of the human upper limbs.
Bi-headed fibers
They form a spindle-shaped rounded muscle. It consists of two heads: a short one, which performs arm adduction, and a long one, which produces abduction. The latter starts from the supraarticular tubercle of the scapula. The short head departs from the coracoid process. At the place of their connection, the abdomen is formed. It attaches to the tubercle on the radius. In the medial direction there are several fibrous bundles. They form a lamellar process - aponeurosis. Then it passes into the shoulder fascia. The tasks of the biceps are external rotation and flexion of the forearm at the elbow.
Coracoid fibers
They form a flat muscle. It is covered by a short head of a two-headed segment. The coracoid muscles of the upper extremities of a person begin at the top of the same-named process of the scapula. Attached fibers below the center of the medial part of the humerus. Due to their contraction, the shoulder rises, the hands are brought to the median line.
Shoulder fibers
They formed a wide fusiform muscle. Its beginning is the anterior and outer surfaces of the shoulder bone. Fixation is made to its tubercle andelbow joint capsule. The fibers are entirely in the lower arm (on the front side) under the biceps.
Elbow segment
This muscle has a pyramidal shape. Its origin is the lateral epicondyle of the shoulder bone. The fibers are attached to the back of the body of the ulna and the process of the same name. Contracting, the muscle extends the forearm. It also coordinates the retraction of the capsule in the elbow joint.
Tri-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 head from the posterior surface. The elements are connected into a spindle-shaped abdomen. It subsequently passes into the tendon. The abdomen is attached to the joint capsule and the elbow process. With the contraction of the fibers, the forearm is unbent, the arm is retracted and the shoulder is brought to the body. The muscle is located from the olecranon to the shoulder blade.
Forearm fibers
They form two muscle groups: anterior and posterior. Each of them contains fibers of a deep and superficial layer. The latter in the anterior group include the flexors of the hand (ulnar and radial) and fingers, the brachioradial segment, and the round pronator. The department also includes long palmar muscles. In the deep layer there is a square pronator, flexors: long thumb and deep digital. The superficial muscles of the posterior group include the ulna, short and longradial extensors of the wrists, finger and little finger. In the deep layer of the department there is an arch support, muscles that abduct and extend the thumb (short and long), an extensor for the index finger.
Musculature of the hand
Muscles are located on the palmar surface. The fibers are divided into several groups: middle, medial, lateral. On the back of the surface of the hand are the interosseous muscles of the same name. In the lateral group there are fibers that correct the movements of the thumb: opposing, adducting, flexor and abducting. The medial section includes the short palmar muscle and the muscles of the little finger. The latter includes a short flexor, adductor and efferent fibers. The middle group contains vermiform, volar, and dorsal interosseous elements.
Table. Upper limb muscles
| Name | Start | Attachment area |
| Deltoid | Acromeon, scapular spine, clavicle | Deltoid tuberosity of the same name bone |
| Nadostnaya | Supraspinatus scapular fossa | Greater tubercle of shoulder bone |
| Infraspinal | Wall of the infraspinous scapular fossa | Greater tubercle of shoulder bone, joint capsule |
| Round (small and large) | Scapula | Small and large tubercles of the shoulder bone |
| Subscapularis | Rib surface of scapula | Small tubercle of shoulder bone |
| Two-headed | Short head - from the coracoid process, long - from the supraarticular tubercle | Ribular tuberosity |
| Coracohumeral | Coracoid process of scapula | Middle of shoulder bone |
| Shoulder | Lower part of shoulder bone | Una tuberosity |
| Three-headed | Long head - from the subarticular scapular tubercle, lateral and medial - from the shoulder | Olecranon and elbow joint capsule |
| Elbow | Lateral subcondyle of the shoulder bone | Una tuberosity |
| Heroradial | Intermuscular lateral septum and humerus | Distal radius |
| Round pronator | Coronoid process of ulna and medial subcondyle of humerus | Coronal portion of shoulder bone |
| Flexor Carpi Radius | Internal armpit bone of the shoulder, fascia of the forearm | The base of the secondmetacarpal bone |
| Palm long | Internal epicondyle of the shoulder bone | Palmar aponeurosis |
| Flexor carpi ulna | The humeral head originates from the internal epicondyle in the humerus, the coronoid process in the ulnar fascia and bones, the ulna head from the same-named bone | Fifth metacarpal, hamate and pisiform bones |
| Finger flexor superficial | Mesial armpit of humerus, coronoid process of ulna, proximal radial skeletal segment | Medium phalanges 2-5 fingers |
| Finger flexor deep | Upper 2/3 of the anterior side of the elbow bone and interosseous membrane of the forearm | Distal phalanx in thumb |
| Thumb flexor long | Anterior part of the radius | Distal phalanx |
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