The upper limbs are an important working tool. Thanks to their presence, people have the opportunity to perform various movements and actions.
Upper limb anatomy
The structure includes:
- Leather.
- The muscles.
- Bone skeleton.
- Blood vessels.
- Ligaments.
This 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. Equally important is the general condition of the body. 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 extremities are quite extensive. Thanks to their actions, people can capture objects, write, gesticulate, and more. Next, consider what the muscles of the upper limbs are.
Muscle anatomy
Fibers are divided into two types. The first includes the muscles of the shoulder girdle, the second - the free part. Classification is carried out depending on the tasks performed and location (a table will be presented at the end of the article). The muscles of the upper extremities in the shoulder girdle are divided into deltoid, supraspinatal, and infraspinatus, small and large round, as well as subscapular fibers. The structure of the shoulder girdle includes the muscles of the hand, shoulder and forearm.
Large round fibers
They have an oblong flat shape. Begin from the back of the lower corner on the shoulder blade. These muscles of the upper extremities are fixed on a small tubercle in the humerus (on the crest). The back calving adjoins the broad fibers of the back. The large round muscles of the upper extremities, while contracting, pull the shoulder backward, turning it inward. As a result, the hand returns to the torso.
Deltoid fibers
They are presented in the shape of a triangle. Under the lower part of this muscle of the upper extremities are fake bags. The fibers cover the shoulder joint completely and the shoulder muscles locally. The deltoid muscle includes large bundles converging at the apex. They are divided according to tasks. The rear ones pull the arm back, the front ones forward.
The fibers begin from the axis of the scapula (lateral end) and part of the clavicle. The fixation site is the deltoid tuberosity in the humerus. The deltoid muscles of the upper limbs take the shoulders outward until they take a horizontal position.
Small round fibers
They make up an oblong rounded muscle. Its front part is covered by deltoid fibers, the back - by large round ones. The muscle begins from the scapula, slightly lower than the infraspinatus fibers, to which its upper surface is adjacent. The segment is attached to the site on the hump of the humerus and the joint capsule (to the back of it). The muscle turns the shoulder outward, pulls back and pulls the capsule of the joint.
Superficial fibers
They form a muscle of a trihedral shape. It is located in the supraspinatus fossa under the trapezoidal segment. The place of fixation is the back of the capsule of the shoulder joint and the site on a large tubercle of the bone. The muscle begins on the surface of the fossa. When the fibers are reduced, the shoulder rises and the capsule of the joint is pulled out, 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 in the subscapular fossa, and ends in the small tubercle in the humerus and on the front of the joint capsule. By reducing the fibers, the shoulder rotates inward.
Sub-fiber
They form a flat, triangular-shaped muscle. The segment is located in the infraspinatus fossa. The beginning of the fibers is located on its wall and the rear scapular part. It is fixed to the capsule in the shoulder joint and to the middle site on a large tuberosity of the bone, under which there is a dry tendon bag. Contracting, the muscle rotates the shoulder outward, allows you to deflect your raised arm, pulls the capsule of the joint.
Shoulder muscles
It is divided into two groups. The front performs bending, and the rear performs the extension of the shoulder and forearm. The first group includes the biceps, brachial and coracoid muscles. The second section includes the triceps and ulnar muscles of the upper limbs of a person.
Double-headed fiber
They form a spindle-shaped rounded muscle. It consists of two heads: a short one performing the adduction of the arm, and a long one performing abduction. The latter begins from the superarticular tubercle of the scapula. The short head departs from the coracoid process. At the junction of their abdomen is formed. It attaches to a tubercle on the radius. In the medial direction are several fibrous bundles. They form a lamellar process - an aponeurosis. Then he goes into the brachial fascia. The objectives of the biceps are rotation outward and flexion of the forearm at the elbow.
Coracoid fibers
They form a flat muscle. It is covered by the short head of the two-headed segment. The coracoid muscles of the upper extremities of a person begin at the apex of the eponymous process of the scapula. Fiber is attached below the center of the medial part of the humerus. Due to their reduction, the shoulder rises, the hands are brought to the midline.
Humeral fibers
They formed a wide spindle-shaped muscle. Its beginning are the front and outer surfaces of the shoulder bone. Fixation is made to her tubercle and capsule of the elbow joint. The fibers are completely located in the lower shoulder part (on the front side) under the biceps.
Elbow segment
This muscle has a pyramidal shape. Its beginning is the lateral epicondyle of the shoulder bone. Fiber is attached to the back of the body of the ulna and the appendix of the same name. When contracting, the muscle extends the forearm. It also coordinates the elongation of the capsule in the elbow joint.
Triceps fiber
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. Elements are connected into a spindle-shaped abdomen. It subsequently passes into the tendon. The abdomen is attached to the capsule of the joint and the process of the elbow. 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 ulnar process to the scapula.
Forearm fibers
They form two muscle groups: anterior and posterior. In each of them there are fibers of the deep and surface layer. The latter in the front group includes the flexors of the hand (ulnar and radial) and fingers, the brachioradial segment, and the round pronator. The division also includes long palmar muscles. In the deep layer there are a square pronator, flexors: long thumb and deep finger. The superficial muscles of the posterior group include the ulnar, short and long radial extensors of the wrists, finger and little finger. In the deep layer of the department there are arch support, muscles that divert and extend the thumb (short and long), extensor for the index finger.
Brush muscles
Muscles are located on the palmar surface. Fibers are divided into several groups: medium, medial, lateral. On the back of the surface of the hand are the same bone muscles. In the lateral group there are fibers that correct the movements of the thumb: opposing, leading, flexors and abduction. The short palmar muscle and the muscles of the little finger are included in the medial section. The latter includes a short flexor, leading and discharge fibers. In the middle group there are vermiform, palmar and dorsal interosseous elements.
Table. Muscles of the upper extremities
Title | Start | Attachment Area |
Deltoid | Acromeon, scapular spine, collarbone | Deltoid tuberosity of the same bone |
Nadostnaya | Supraspinatal fossa | Large tubercle of the bone of the shoulder |
Subostea | The wall of the infraspinatal fossa | Large tubercle of the shoulder bone, joint capsule |
Round (small and large) | Shovel | Small and large tubercles of the shoulder bone |
Subscapular | Costal surface of the scapula | Small shoulder bone tubercle |
Two-headed | Short head - from the coracoid process, long - from the supra-articular tubercle | Radial tuberosity |
Coraco-humeral | The coracoid process of the scapula | The middle of the shoulder bone |
Humeral | Lower part of the shoulder bone | Ulnar tuberosity |
Triceps | The long head is from the subarticular scapular tubercle, the lateral and medial from the shoulder | Elbow and capsule of the elbow joint |
Elbow | Lateral submandula of the shoulder bone | Ulnar tuberosity |
Plecheradial | Intramuscular lateral septum and humerus | The distal part of the radius |
Round pronator | Coronoid process of the ulna and medial submuscle of the humerus | Coronary part of the shoulder bone |
Radial wrist flexor | Inner submandula of the shoulder bone, fascia of the forearm | The base of the second metacarpal bone |
Palm long | Inner epicondyle of the shoulder bone | Palmar aponeurosis |
Ulnar flexor | The humeral head departs from the internal epicondyle in the humerus, coronoid process in the ulnar fascia and bones, the ulnar head - from the eponymous bone | Fifth metacarpal, hooked and pea-shaped bones |
Finger flexor surface | The medial submandula of the shoulder bone, coronoid process of the elbow joint, the proximal part of the radial skeletal segment | Middle 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 the thumb |
Thumb flexor long | The front of the radius | Distal phalanx |
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