In man shoulder joint has a large range of motion, but on a par with this, the depth of the articular fossa has no big sizes. As a result, after any injury, a habitual dislocation of the shoulder joint occurs and this pathology occurs very often. This situation occurs mainly in men aged 20 to 50 years. In childhood and old age, trauma often leads to the development of epiphysiolysis (separation of the growth zone in a child) or fractures. There are dislocations depending on the displacement of the head in relation to the articular cavity.

Habitual dislocation is a condition that develops within 6 months after the reduction of the primary dislocation. There are cases when a person can adjust the shoulder joint several times during the day. On average, the frequency of dislocation is 10 times during the year, gradually leading to changes in the joint.

The reasons

There is a habitual dislocation of the shoulder or elbow joint of the forearm as a result of many reasons. It:

• severe primary traumatic dislocation;
• untreated dislocation of the shoulder joint;
• contacting a doctor immediately after an injury;
• insufficiently long immobilization, resulting in subluxation of the shoulder joint;
• sports injuries.

There are also predisposing factors that are associated specifically with the structure of the joint. Such factors could be:

• large spherical head size;
• small size and small concavity of the articular cavity;
• overstretched capsule;
• poor muscle development.

Varieties

Anterior habitual dislocation is very common. It occurs as a result of a violent impact on the hand laid back or when it is turned sideways. Occurs as a result of a fall on an outstretched arm or forearm area.

Rarely, an upper dislocation occurs, which results from a direct blow to the forearm or a strong muscle contraction. With a fixed pectoralis major muscle, the large tubercle of the humerus comes off. A dislocation can be posterior when the bone is displaced posteriorly.

Symptoms

Habitual dislocation of the humerus has its own symptoms that allow it to be diagnosed. Often the head and torso lean in the direction where the injury occurred, with a healthy hand, a person supports the forearm area on the injured side. The area of ​​the shoulder goes down, shifts forward, changes the configuration of the shoulder joint. The area of ​​the elbow and forearm is retracted from the body.

If you measure the axis of the humerus, then it passes by the fossa of the joint, the deviation occurs anteriorly and in the middle. When feeling the articular cavity, a void is determined there, and the head of the bone after the injury is not in its position. You can find the head of the bone with a simple rotation. Active movements are impossible, passive ones hurt, they are springy in the shoulder, if you try to touch the forearm area.

The main thing is to ask the patient in detail about the frequency of dislocations. If they occur frequently, then there is no doubt about the diagnosis.

Complications of habitual dislocation

In some cases, the dislocation can have complications, as a result of which the articular surface of the humerus or the glenoid fossa of the scapula is damaged. Most often, the area of ​​\u200b\u200bthe large tubercle of the humerus suffers. In elderly people, a fracture of the humerus occurs. A dislocation in a child is accompanied by a separation of the growth zone. Rarely, there is damage to blood vessels and nerves, which is an indication for immediate surgery.

Diagnostics

In order to diagnose the pathology, it is necessary to take x-rays. Even though it hurts, they are done in two projections. If questions remain after the injury, an MRI is often ordered. It allows you to understand not only the localization of the head, but also the state of the surrounding soft tissues, to prepare as much as possible for the operation. The picture allows you to visualize the place where it hurts the most.

Treatment

It is absolutely impossible to use exercises with habitual dislocation, this is a very big mistake. Even if these exercises are done systematically, they will not lead to anything good. After the exercises are performed, the consequences can be in the form of repeated habitual dislocation and deterioration in the condition of the tissues that stabilize the joint. The only option that will eliminate the consequences of the injury is surgery. After it, rehabilitation is carried out, which will allow you to return to normal function. Of particular importance is surgical intervention in a child.

The first option is arthroscopic Bankart surgery. This operation allows you to treat habitual dislocation most effectively and is applied first. It is done with the help of punctures into which the camera and the manipulator are inserted. After studying the condition of the joint, additional punctures can be made, additional instruments are introduced through them. With their help, during the operation, the articular lip is restored after an injury, since the old one is practically erased.

If arthroscopic surgery does not help in all cases, a different technique is used to fully treat the consequences of the injury. Occurs during ligament plastic surgery, suturing the stretched joint capsule.

Recovery

Rehabilitation is an effective addition to treating habitual dislocation of the shoulder. It is carried out not only in the shoulder area, but also in the forearm. Apply special exercises that are of particular importance to the child. Rehabilitation is performed only under the supervision of the attending physician, the exercises depend on the severity of the surgical intervention and the physical development of the patient. In parallel, exercises for the forearm are performed.

It will be useful for an adult and a child to do massage, which is also complemented by rehabilitation. It is performed carefully so that it does not hurt. They do it after the wound has completely healed, it is better that it be an experienced specialist.

Physiotherapeutic methods of treatment are also used, they can be performed for an adult and a child. Moreover, through fixation, which lasts for about three to six weeks. The required list of procedures can be represented as follows:

1. Electrophoresis. It is performed with the addition of Novocaine and anti-inflammatory drugs. The essence of the technique is the application of direct currents to the site of damage.
2. Diodinamik. The technique is based on the use of alternating currents at the site of surgical intervention.
3. Ultrasound. The procedure is performed with or without medication. Anti-inflammatory ointments are often used, with the help of the technique, the active substances penetrate deeper into the tissues.
4. Magnetotherapy. The essence of the technique is the use of a magnetic field at the site of surgical intervention. With the help of the procedure, tissue trophism and their regenerative ability are improved.
5. Shock wave therapy. Promotes tissue nutrition, restores them after surgery.
6. Ultraviolet irradiation. It is applied to the site of a postoperative wound, promotes recovery, has a bactericidal effect, dries the wound. Additionally, the technique promotes the production of vitamin D by tissues.
7. Mud. They have a local restorative effect.
8. Paraffin applications. Improve blood flow in the shoulder joint.

An excellent addition to the rehabilitation treatment will be a visit to the pool. In the water, you can perform gymnastics, which helps to increase the range of motion. But sports and other loads will have to be completely abandoned. The period of complete recovery of the capsule and ligaments is from three to four months, after which you can give gradual load on the operated joint.

Habitual dislocation is a rather complex pathology that requires a responsible approach from both the doctor and the patient. After the treatment, it is necessary to follow all the recommendations of your attending physician, otherwise, re-injury simply cannot be avoided. Yes, and there is no guarantee that changes in the joint can be eliminated completely. There is no need to waste time, and if the shoulder often “pops out”, you should consult a doctor and get treated so that you can use your shoulder joint normally later.

2016-04-16

The structure of the ankle joint - what you need to know about it?

The ankle joint is considered the most vulnerable among others. After all, it is not for nothing that the legendary Achilles tendon is located here, which caused the death of the mythical hero. And today, knowledge of the anatomy of the ankle joint is necessary for everyone, because if it is damaged, not only heroes can lose their strength and capabilities.

• Bone elements of the joint
• Ankle muscles
• Ankle ligaments
• Blood supply and nerve endings
• Functional features of the ankle

The ankle connects the bones of the lower leg and foot, thanks to it, a person makes movements with his feet and walks normally. The structure of the ankle joint is quite complex: several bones are connected in it and the system of cartilage and muscles that connects them together. In addition, a network of blood vessels and nerve plexuses is formed around each joint, providing tissue nutrition and coordination of movements in the joint.

The ankle joint is forced to support the weight of the human body and ensure its proper distribution when walking. Therefore, the strength of the ligamentous apparatus, cartilage and bone tissue is of great importance.

It has its own anatomical boundaries. At the top, the joint is bounded by an imaginary line 7-8 cm above the medial malleolus (a clearly visible protrusion on the inside of the ankle). At the bottom, it is separated from the foot by a line connecting the tops of the medial and lateral (located on the opposite side) ankles.

In the area of ​​​​the joint, the following departments are distinguished:

1. Anterior - passing to the back of the foot.
2. Posterior - area of ​​the Achilles tendon. This is the most powerful tendon in the human body, because it can withstand a load of up to 400 kg. It connects the heel bone and calf muscle, and in case of injury, a person loses the ability to move his feet.
3. Internal - the area of ​​the medial malleolus.
4. External - the area of ​​​​the lateral ankle.

Bone elements of the joint

The ankle joint is made up of two bones of the lower leg. This is the tibial and fibular. Also attached to them is the foot bone, or talus. The latter is sometimes also called supraheel.

The lower (distal) ends of the tibia together form a nest, which includes the process of the talus of the foot. This connection is a block - the basis of the ankle joint. It has several elements:

• external malleolus - formed by the distal end of the fibula;
• distal surface of the tibia;
• inner malleolus (represents the distal end of the tibia).

The anterior and posterior edges, the inner and outer surfaces are distinguished on the outer ankle. At the posterior edge of the outer malleolus is a depression where the tendons of the long and short peroneal muscles are attached. On the outer surface of the outer ankle, the lateral ligaments and fascia of the joint are attached. Fascia are the connective tissue membranes of the joints. They are formed by sheaths covering muscles, nerves and tendons.

On the inner surface is hyaline cartilage, which, together with the upper surface of the talus, makes up the outer fissure of the ankle joint.

What does it look like?

The distal surface of the tibia resembles an arc, on the inside of which there is a process. The anterior and posterior edges of the tibia form two outgrowths, which are called the anterior and posterior malleolus. On the outside the fibula notch is located on the tibia, on both sides of which there are two tubercles, it also partially houses the external ankle. Together they form the tibiofibular syndesmosis. It is of great importance for the normal functioning of the joint.

The distal epiphysis of the tibia is divided into 2 parts - large, posterior and smaller - anterior. The articular surface is divided by a small bone formation - the crest, into the medial (inner) and lateral (outer) parts.

The medial malleolus is formed by the anterior and posterior tubercles. The anterior is large and separated from the posterior by a fossa. To the inner part of the ankle, which has no articular surfaces, the fascia of the joint and the deltoid ligament are attached.

The outer part is covered with hyaline cartilage and together with inner surface the talus forms the internal fissure of the ankle joint.

The talus connects the bones of the lower leg and the calcaneus. It consists of a body, a block and a neck with a head. With the help of a block, the talus is connected to the bones of the lower leg. It is located in the so-called "fork" formed by the distal tibia. Top part the block is convex, on it there is a groove corresponding to the crest of the distal epiphysis of the tibia.

The anterior part of the block is somewhat wider than the posterior, and passes into the head and neck of the talus. Behind is a small tubercle with a groove, where the tendon of the long flexor is located. thumb.

Ankle muscles

Muscles - flexors of the foot pass along the back and outer surface of the ankle joint:

• tibialis posterior,
• triceps muscle,
• long flexor of the big toe,
• plantar,
• long flexor of all other toes.

The extensor muscles are located in the anterior ankle joint:

• long extensor thumb,
• tibialis anterior,
• long extensor of other toes.

Arch support and pronators provide movement in the joint in and out. Pronators include short and long, as well as the third peroneal muscle. To the supinators - the anterior tibial and long extensor of the thumb.

Ankle ligaments

These elements perform an important function in providing movement in the joint. They hold the bone components together and allow the production of various movements in the joint.

Ligaments of the ankle joint are subdivided into ligaments of the tibiofibular syndesmosis - between the outer surface of the tibia and the malleolus of the fibula, and the outer and inside ankle joint.

1. Ligaments of the tibiofibular syndesmosis are powerful formations that are divided into interosseous, posterior inferior tibiofibular, anterior inferior tibiofibular and transverse.
   • The interosseous ligament is a continuation of the interosseous membrane, its main purpose is to hold the tibia together.
   • The posterior inferior ligament is a continuation of the interosseous ligament and prevents excessive inward rotation.
   • The anterior inferior tibiofibular ligament lies between the fibular notch of the tibia and the lateral malleolus and prevents excessive outward rotation of the foot.
   • The transverse ligament is located under the previous one and also prevents the foot from rotating inward.
2. The external lateral ligaments are the anterior and posterior talofibular, calcaneofibular.
3. The medial lateral ligament, or deltoid, is the most powerful of the ankle ligaments. It connects the inner ankle and the bones of the foot - the talus, calcaneus and navicular.

Blood supply and nerve endings

This joint receives blood supply from three branches of the blood arteries - the anterior and posterior tibial and peroneal. They branch out many times in the area of ​​the joint. They form vascular networks in the ankles, capsules and ligaments of the joint.

The venous outflow is represented by a very extensive network of vessels, divided into internal and external networks. They then form the small and great saphenous veins, anterior and posterior tibial veins. All of them are interconnected by an extensive network of anastomoses (connections of adjacent vessels forming a single network).

Lymphatic vessels repeat the course of the blood vessels, respectively, the outflow of lymph goes in front and inside parallel to the tibial artery, and outside and behind - the peroneal.

In the ankle joint, branches of such nerve endings pass: the superficial small and tibial nerves, the deep tibial nerve and the sural nerves.

Functional features of the ankle

The range of motion in this joint is 60-90 degrees. Movements are possible around its axis located in the center of the inner ankle and through a point anterior to the outer ankle. It is also possible to move the foot in and out, and in addition, plantar flexion and extension of the spot.

The ankle joint is often exposed to various traumatic effects. This leads to torn ligaments, fracture and tearing of the ankles, cracks and fractures of the tibia. Nerve and muscle damage is also common.

Bone anatomy of the shoulder joint.
The shoulder joint is a typical spherical joint formed by the head of the humerus and the glenoid cavity of the scapula. The glenoid cavity of the scapula is a flattened pear-shaped or inverted comma-shaped fossa with a surface approximately 4 times smaller than the surface of the head of the humerus. The head of the humerus is rotated approximately 30° posteriorly from the transverse axis of the elbow joint, and the scapula is rotated the same angle anteriorly from the frontal plane of the body; thus, the head of the humerus and the glenoid cavity of the scapula face exactly each other. During movements in the shoulder joint, the scapula rotates, turning its glenoid cavity up, down, outward or inward, so that the center of the head of the humerus remains inside it. When such a centered position of the head of the humerus in the articular cavity is violated, there is a danger of dislocation in the shoulder joint.

Joints of the clavicle.
The medial end of the clavicle is involved in the formation of the sternoclavicular joint, and the lateral end is involved in the formation of the acromioclavicular joint. The clavicle rotates around its axis and serves as a support for the shoulder joint, since it alone connects the upper limb with the axial skeleton. At the same time, the clavicle acts as a spacer that holds the shoulder joint away from the chest for its greatest mobility.

Articular capsule, articular lip and ligaments of the shoulder joint.
The capsule of the shoulder joint is the most spacious and loose compared to the capsules of all other large joints, but it also makes an important contribution to maintaining its stability. Together with the articular lip, it is attached to the scapula, and in front it is strengthened by several ligaments: the coraco-humeral and three articular-humeral: upper, middle and lower. There are anatomical variants of the shape and position of the articular lip and ligaments: there is, for example, a hole between the anterior upper part of the articular lip and the edge of the glenoid cavity of the scapula, which communicates the articular cavity with the tendinous sac of the subscapularis muscle. Some of these anatomical variations are particularly predisposing to shoulder injury.

The articular lip not only serves as a place of attachment for the articular capsule and its constituent ligaments, but also enlarges the articular cavity, deepening the articular fossa approximately 1.5 times. By elevating the edges of the glenoid cavity, it acts as an additional support for the head of the humerus, preventing it from slipping out. After the removal of the articular lip, the shoulder joint largely loses its ability to withstand forces that shift the articular surfaces relative to each other, and becomes significantly less stable.

Anatomy of the muscles of the shoulder joint.
The muscles acting on the shoulder joint can be divided into three anatomical and functional groups: muscles shoulder girdle, chest and back muscles and shoulder muscles.

Muscles of the shoulder girdle. Four muscles from this group: supraspinatus, infraspinatus, small round and subscapular - form the so-called muscle capsule of the shoulder joint, or rotator cuff of the shoulder. The supraspinatus muscle starts from the walls of the supraspinatus fossa, goes outward, filling it, passes under the acromion and attaches to the large tubercle of the humerus, while fusing with the fibers of its tendon to the posterior surface of the capsule of the shoulder joint. It is involved in the abduction of the arm to the maximum angle, and its paralysis in neuropathy of the suprascapular nerve reduces the strength of abduction by almost half. The infraspinatus and teres minor muscles originate from the posterior surface of the scapula below its spine and insert on the posterior surface of the greater tubercle of the humerus under the insertion of the supraspinatus muscle. Their joint action consists in extension and external rotation of the shoulder. Together, these two muscles provide approximately 80% of the total external rotation force of the adducted shoulder. The infraspinatus is more active when the arm is down, and the teres minor is more active when the arm is raised 90°. The subscapularis is the only anterior part of the rotator cuff of the shoulder joint; it starts from the anterior surface of the scapula, attaches to the small tubercle of the humerus and carries out its internal rotation, and if the arm is laid aside, it leads the arm to the body, simultaneously deflecting it forward. The subscapularis tendon is woven into the joint capsule and strengthens the shoulder joint in front.

The deltoid muscle is the largest of the muscles of the shoulder girdle. Anatomy: starting in three bundles from the clavicle, acromion and spine of the scapula, it covers the shoulder joint and descends along the humerus, where it is attached to the deltoid tuberosity halfway to the elbow joint. The anterior part of the deltoid muscle flexes the arm at the shoulder joint and, together with the middle part, abducts the arm, while the back part of the muscle extends the arm. The deltoid muscle is able to abduct the arm to the maximum angle even without the involvement of the supraspinatus muscle, and its paralysis in case of neuropathy of the axillary nerve reduces the force of arm abduction by half.

The teres major muscle originates from the inferior angle of the scapula and inserts on the crest of the lesser tubercle of the humerus behind the insertion of the latissimus dorsi. From above, the axillary nerve and the posterior circumflex artery adjoin the humerus, which pass through a four-sided opening, bounded by the large round muscle from below, the small round muscle from above, the long head of the triceps muscle of the shoulder from the inside and the humerus from the outside. Together with the latissimus dorsi muscle, the teres major extends the shoulder, rotates it inward and leads to the trunk.

Muscles of the chest and back. The pectoralis major muscle begins in two wide parts: the clavicle and sternocostal, separated by a groove, and narrows towards the shoulder, attaching to the crest of the large tubercle of the humerus with the lower bundles higher than the upper ones. Due to her strength, she latissimus dorsi backs strengthen the shoulder joint, but they can also contribute to dislocation in it. It is shown that with horizontal abduction of the arm, the lower bundles of the sternocostal part of the large chest muscle are stretched to the limit, and since the anterior subluxations of the shoulder arise, in particular, from a sharp horizontal abduction of the arm, it is possible that the direct cause of the subluxation is the passive traction of the fibers of the pectoralis major muscle and the latissimus dorsi muscle.

Shoulder muscles. Both heads of the biceps brachii originate from the scapula. The short head starts from the coracoid process of the scapula with a common tendon with the coracobrachialis muscle. The long head begins just above the edge of the articular cavity of the scapula - from the supra-articular tubercle and the posterior part of the articular lip; its tendon passes through the cavity of the shoulder joint above the anterior surface of the head of the humerus and, leaving the joint, descends along the intertubercular groove, surrounded by the intertubercular synovial sheath and covered by the transverse ligament of the humerus. Both heads are combined into a long muscular abdomen, which is attached to the tuberosity of the radius. In this way biceps shoulder gets the opportunity to act both on the shoulder and on the elbow joint. It is well known that she flexes her arm at the elbow joint and rotates her forearm outward. It has also been suggested that it contracts to pull the head of the humerus downward, but recent electromyographic studies cast doubt on this, since the electrical activity of the biceps brachii almost does not increase if there is no movement in the elbow joint. However, this does not mean that the biceps of the shoulder cannot strengthen the shoulder joint with its strong tendon, both at rest and under tension during flexion of the forearm.

Blood supply and innervation.
The blood supply to the muscles of the shoulder girdle is almost entirely due to the axillary artery and its branches. It crosses the axillary cavity, heading from the outer edge of the first rib to the lower edge of the pectoralis major muscle, where it continues into the brachial artery. The axillary artery lies under the pectoralis major muscle, and in the middle it is crossed in front by the pectoralis minor muscle before attaching to the coracoid process of the scapula. The artery is accompanied by a vein of the same name.

The innervation of the muscles of the shoulder girdle is carried out by the nerves of the brachial plexus. It is formed by the connection of the anterior branches of the four lower cervical spinal nerves and most of the anterior branch of the first thoracic nerve. The brachial plexus begins at the base of the neck, continues forward and downward, and penetrates into the axillary cavity, passing under the clavicle at the junction of its first and second distal thirds. Fractures of the clavicle at this location can damage the brachial plexus. It then passes under the coracoid process of the scapula and gives off nerves that continue further down the arm.

pectoralis major muscle massive, fan-shaped, occupies a significant part of the anterior chest wall. According to the places of its beginning, the clavicular part starts from the medial half of the clavicle; the sternocostal part originates from the anterior surface of the sternum and the cartilages of the upper six ribs; the abdominal part (weakly expressed), starts from the anterior wall of the vagina of the rectus abdominis muscle. The bundles of parts of the pectoralis major muscle, converging noticeably, pass in the lateral direction and are attached to the crest of the greater tubercle of the humerus. The pectoralis major muscle is separated from the deltoid muscle by a well-defined deltoid-pectoral groove, which passes upward and medially into the subclavian fossa. Located superficially, this muscle, together with the pectoralis minor, forms the anterior wall of the axillary cavity and limits the axillary fossa with its lower edge. The muscle of the raised arm lowers and leads to the body, while turning it inward. If the arm is strengthened in a raised position, it lifts the ribs and sternum (auxiliary respiratory muscle), contributing to the expansion of the chest.

pectoralis minor muscle flat, triangular in shape, located directly behind the pectoralis major muscle. Starts from 2-5 ribs, near their anterior ends. Heading upward and laterally, it is attached by a short tendon to the coracoid process of the scapula. The muscle tilts the scapula forward; with a strengthened shoulder girdle, it raises the ribs, contributing to the expansion of the chest.

subclavian muscle small in size, occupies a slit-like gap between 1 rib and clavicle. It starts from the cartilage of the 1st rib, passes in the lateral direction and is attached to the lower surface of the acromial end of the clavicle. The muscle pulls the collarbone down and forward, helping to strengthen the sternoclavicular joint.

Serratus Anterior wide, quadrangular, adjacent to the chest from the side, forms the medial wall of the axillary cavity. It starts with large teeth from the upper eight to nine ribs and is attached to the medial edge and lower angle of the scapula. Its upper and middle bundles lie horizontally, the lower ones are oriented obliquely and pass from front to back and from bottom to top. The lower 4-5 teeth of the serratus anterior, where they begin, go between the teeth of the external oblique muscle of the abdomen. The muscle moves the scapula, especially its lower angle, forward and laterally; the lower bundles contribute to the rotation of the scapula around the sagittal axis, as a result of which the lateral angle of the scapula moves upward and the medial arm rises above the horizontal. With a reinforced shoulder blade, the anterior serratus muscle raises the ribs, contributing to the expansion of the chest.

• • Muscles acting on the joints of the shoulder girdle

Muscles acting on the joints of the shoulder girdle

The muscles acting on the joints of the shoulder girdle include: pectoralis major and pectoralis minor, subclavian and serratus anterior. These muscles lie superficially.

pectoralis major muscle- a massive, fan-shaped muscle that occupies a significant section of the anterior chest wall. It starts from the clavicle, from the anterior surface of the sternum and the cartilages of the upper six ribs, from the anterior wall of the sheath of the rectus abdominis muscle and is attached to the crest of the large tubercle of the humerus.

Function of this muscle: lowers the raised arm and leads to the body, while turning it inward. If the arm is strengthened in a raised position, it lifts the ribs and sternum, contributing to the expansion of the chest.

pectoralis minor muscle- flat triangular, located behind (under) the pectoralis major muscle. It starts from the II-IV ribs and is attached by a tendon to the coracoid process of the scapula.

The function of this muscle: tilts the scapula forward; with a fixed shoulder girdle, it raises the ribs, contributing to the expansion of the chest.

subclavian muscle- occupies the gap between the 1st rib and the clavicle.

Function of this muscle: pulls the collarbone down and forward.

Serratus anterior- a wide, quadrangular muscle. Adjacent to the chest from the side; starts from the upper eight ribs and is attached to the inner (medial) edge and the lower corner of the scapula.

The function of this muscle: moves the scapula forward and outward (laterally); rotates the scapula, as a result of which the arm rises above the horizontal.

"Muscles acting on the joints of the shoulder girdle" and other articles from the section Diseases of the musculoskeletal system

In the region of the pectoral limbs, the muscles are located: 1) the shoulder girdle; 2) shoulder joint; 3) elbow joint; 4) carpal joint and 5) finger joints.

Rice. one. Scheme of the distribution of muscle groups on the thoracic limb (A - from the lateral surface, B - from the medial):

1 - extensors of the shoulder joint; 2- abductors of the shoulder joint; 3 - extensors of the elbow joint; 4, - wrist extensors; 5 - finger extensors; 6 - flexors of the shoulder joint; 7 - wrist flexors; 8 - finger flexors; 9 - adductors of the shoulder joint; 10 - flexors of the elbow joint.

Shoulder muscles

In the shoulder multiaxial joint, extension and flexion, abduction and adduction are possible, as well as, albeit to a weak degree, pronation and supination of the free limb.

Extensors (extensors) pass through the top of the shoulder joint, flexors (flexors) are located inside the angle of the joint. The abductors lie on the lateral surface of the scapula, and the adductors lie on the medial surface of the scapula.

Flexors are assisted by the latissimus dorsi, the long head of the triceps brachii, and the deep pectoralis muscle. The pectoral muscles help the adductors, and the rhomboid muscle helps the abductor. Pronators are assisted by the brachiocephalic and thoracic superficial muscle and the latissimus dorsi (Fig. 2 and 3).

Extensors:

1. Prespinous muscle - m. supraspinatus (Fig. 2-4) - pinnate in structure, fills the entire supraspinatus fossa, laterally covered by the trapezius muscle. It ends with two legs on the lateral and medial tubercles of the humerus.

Function - unbends the shoulder joint.

Flexors:

1. Deltoid -m. deltoldeus (13) - flat, fleshy, triangular in shape, lies behind the scapular spine. It covers the infraspinatus muscle, with which it is firmly fused with its initial tendon, as well as the small round muscle and partially the triceps muscle of the shoulder. Consists of scapular and acromial parts.

The scapular part begins with a wide lamellar tendon (aponeurosis) from the scapular spine.

The acromion originates from the acromion. Both parts end on the deltoid roughness of the humerus.

Function - flexes and supinates the shoulder joint.

2. teres minor muscle - m. teres minor (6) - lies behind the infraspina; laterally covered by the deltoid muscle. It starts from the distal third of the caudal edge of the scapula. Ends on the elbow line.

Function - flexes the shoulder joint and supinates it.

3. teres major muscle - m. teres major (7). It starts from the proximal half of the caudal edge of the scapula. It ends on the rounded roughness of the humerus along with the latissimus dorsi muscle.

F u n to c and I - flexes the shoulder joint and pronates it.

Abductors:

1. infraspinalis muscle - m. infraspinatus (5) - fills the infraspinal fossa; covered from the surface deltoid muscle. Begins in the posterior fossa. It ends on the lateral tubercle of the humerus.

Adductors:

1. Subscapularis - t. subscapulars (3 - 9) - multi-pinnate, fills the subscapular fossa, in which it is fixed. It ends on the medial tubercle of the humerus.

2. coracobrachial muscle - m. coracobrachial (Fig. 3- 8) . It begins on the coracoid process of the scapula. It ends distally with a round roughness.

Function - helps adductors.

Fig.2. Muscles of the scapula and shoulder from the lateral surface:

A - dogs; B - horses; B - scheme of fixing muscles on bones. 1 - brachiocephalic muscle; 2 - trapezoid m.; 3 - the widest m. of the back; 4 - preosnaya m.; 5 - transverse m; 6 - small round m.; 7 - large round m; 8 - coraco-humeral m.; 9 - subscapular m.; 10 - elbow m.; 11 - tensile fascia of the forearm 12 - biceps m. of the shoulder; 13 - deltoid m., its scapular part; 13 "- deltoid m., its acromial part; 14 - three-headed m. of the shoulder, its long head; and 14" - its lateral head; 16 - dentate ventral m.; 17 - shoulder m.; 18-beam flexor of the wrist.

Rice. 3. Muscles of the scapula and shoulder from the medial surface:

A - dogs; B - horses; D - scheme of fixing muscles on the bones.

Elbow muscles

In a uniaxial elbow joint, only flexion and extension are possible, and in a dog, in addition, rotation of the forearm.

Extensors:

1. Triceps brachii - m. triceps brachii (14) - very powerful, fills the triangular space between the scapula, humerus and olecranon. It consists of three heads: long (two-articular), lateral and medial (single-articular).

Long head - caput longum. It starts from the caudal edge of the scapula, ends on the ulnar tubercle, having underneathtendinous bursa . Helps to flex the shoulder joint.

The lateral head - caput laterale and the medial head - caput mediale start from the proximal third of the humerus, each on its own side. They end on the elbow tubercle.

.2. Elbow muscle - m. anconaeus (10) - lies under the lateral head of the triceps muscle of the shoulder and is firmly fused with it. It starts along the edges of the cubital fossa; ends on the lateral surface of the ulnar tubercle.

3. Tensioner fascia of the forearm - m. tensor fasciae antebrachii (Fig. 3- 11) , lies on the medial surface of the long head of the triceps brachii, along its caudal edge. It starts from the caudal edge of the scapula, ends on the ulnar tubercle and in the fascia of the forearm.

Function - unbends the elbow joint, helps to bend the shoulder joint.

Flexors:

1. Biceps brachii - m. biceps brachii (20) - lies on the anterior surface of the humerus.

It starts from the tubercle of the scapula, approaches in the intertubercular groove of the humerus. In the area of ​​the block of the humerus under the tendon Has a synovial cavity . The muscle ends on the roughness of the radius.

2. shoulder muscle -m. brachialis internus (17) - located directly on the humerus. It starts under the neck of the humerus, ends at the roughness of the radius.

Muscles of the wrist

The carpal joint in domestic animals is uniaxial and allows only flexion and extension.

The abdomens of the muscles acting on the carpal joint are located proximal to the joint and lie at the ends of the forearm, and between the extensors of the wrist are the extensors of the fingers, and between the flexors of the wrist are the flexors of the fingers. (Fig. 86, 87).

Extensors:

1. extensor carpi radialis - m. extensor carpi radialis (Fig. 86- 18) - lies on the dorsal surface of the forearm. It forms the dorso-medial contour of the forearm; begins on the crest of the lateral epicondyle of the humerus, ending at the roughness of the III metacarpal bone.

In the area of ​​the distal quarter of the forearm and on the wrist there is synovial sheath of the tendon - vagina synovialis tendinis.

2. Long thumb abductor - m. abductor pollicis longus (3). Begins on the lateral surface of the radius, crossing the tendon from the dorsal surface radial extensor wrist, ends at the head of the II metacarpal bone.

Flexors:

1. Elbow extensor wrists - m. extensor carpi ulnaris (5) . It begins on the extensor epicondyle of the humerus (laterally). It ends on the accessory bone of the wrist.

Function. Only in the dog, the extensor carpi ulnaris extends the wrist, while in ungulates it acts as a wrist flexor.

2. flexor carpi radialis - m. flexor carpi radialis (Fig. 87- 11). It begins on the medial (flexion) epicondyle of the humerus, ends on the head of the metacarpal bone.

The tendon in the wrist is covered with a synovial sheath - vagina synovialis tendinis.

3 . Flexor carpi ulnaris - m. flexor carpi ulnaris (4) - begins on the medial (flexion) epicondyle of the humerus, immediately behind the radial flexor of the wrist, ends with a common tendon on the accessory bone of the wrist.

Muscles of the fingers

Among the muscles acting on the fingers, there are: long digital extensors and flexors, and short finger flexors. The long digital extensors include the common digital extensor and the lateral digital extensor. The abdomens of these muscles lie on the dorsolateral surface of the bones of the forearm, between the extensors of the wrist, and their tendons go to the fingers: from the common digital extensor to the third phalanges of the fingers, and from the lateral digital extensor to the third and second phalanges of the fingers.

The long flexors of the fingers are located on the medio-volar surface of the bones of the forearm, also between the flexors of the wrist; these include superficial and deep digital flexors. Their tendons are directed from the deep flexor of the fingers to the third phalanges, and from the superficial flexor of the fingers to the second phalanges.

Since the long finger muscles are fixed on the epicondyles of the humerus and pass through the ulnar, carpal, metacarpophalangeal, interphalangeal joints, they are polyarticular muscles. Therefore, the extensors of the fingers help the flexors of the elbow joint, extensors of the metacarpus and unbend the metacarpophalangeal joints. The finger flexors, on the other hand, help the elbow extensors, the metacarpus flexors, and each other.

Short digital flexors are located on the volar surface of the metacarpal bones and act on the metacarpophalangeal joints. These muscles in ruminants and horses have evolved into ligaments that suspend the sesame bones.

Extensors:

1. General extensor fingers - m. extensor digitalis communis. It originates on the extensor epicondyle of the humerus and inserts on the extensor process of the distal phalanx.

In the area of ​​​​the wrist there is a synovial sheath of the tendon - vagina tendinis synovitis.

Ruminants have two heads with independent tendons. The medial head adjoins directly to the radial extensor of the wrist and is called the special extensor of the third finger (6).

Function - acts on several joints; it extends the fingers, helps the extensors of the wrist and flexors of the elbow joint.

2. Lateral extensor of fingers - m. extensor digitalis lateralis (1), or in ruminants - a special extensor of the fourth finger - lies between the common extensor of the fingers and the ulnar extensor of the wrist. Ends on 2 phalanges of fingers.

Function - unbends fingers and wrist.

Flexors:

1. Superficial finger flexor - m. flexor digitalis superficialis (Fig. 87-9)

It starts just behind the flexor carpi ulnaris and may have 1 or 2 heads. It ends at the distal end of the I and proximal end of the II phalanx of the corresponding finger.

Function - flexes the fingers and wrist, helps the extensors of the elbow joint.

2. Deep finger flexor - m. flexor digitalis profundus (Fig. 87-8) - lies directly on the volar surface of the bones of the forearm. It originates tendinously on the medial epicondyle of the humerus, along with the superficial flexor digitorum. Beneath the tendon is the bursa. On a polydactyl limb, the tendon gives off separate branches for each finger. In the horse, it is attached to the flexor surface of the coffin bone. It is separated from the navicular bone by a mucous bag (bursa).

Function - flexes the fingers and wrist, helps the extensors of the elbow joint.

3. Interosseous muscles - m. interosseus (21) - lie on the volar surface of the metacarpal bones. They start from the common volar ligament of the wrist; terminate in two branches on the sesamoid bones of the metacarpophalangeal joints of each finger.

Muscles of the forearm and paw from the lateral surface.

A - B - dogs; B - pigs; G - cows; D - horses; E - fixing muscles on bones.

1 - lateral extensor of the fingers, 2 - common extensor of the fingers, 3 - long abductor of the thumb, 4 - ulnar flexor of the wrist, 5 - radial extensor of the wrist, 6 - extensor of the 3rd finger, 7 - extensor of the 4th finger, 8 - deep flexor of the fingers, 9 - superficial flexor of the fingers, 10 - ulnar muscle, 17 - brachial m., 18 - radial extensor of the wrist, 21 - interosseous muscle, 21 / - its tendon to the common extensor of the fingers.