What muscles act on the shoulder joint? Muscles of the thoracic limb. Symptoms of the disease depending on the stage

In humans shoulder joint has a large range of movements, but at the same time the depth of the articular fossa is small. 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 from 20 to 50 years. In childhood and old age, trauma often leads to the development of epiphysiolysis (severation of the growth zone in a child) or fractures. Dislocations are distinguished depending on the displacement of the head in relation to the glenoid cavity.

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

Causes

Habitual dislocation of the shoulder or elbow joint of the forearm occurs due to many reasons. This:

• severe primary traumatic dislocation;
• untreated shoulder dislocation;
• not seeing a doctor immediately after an injury;
• immobilization is not long enough, resulting in subluxation of the shoulder joint;
• sports injuries.

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

• large spherical head size;
• small size and small concavity of the glenoid cavity;
• overly stretched capsule;
• poor muscle development.

Varieties

Anterior habitual dislocation is very common. It occurs as a result of forceful impact on the arm, retracted posteriorly or when it is turned to the side. Occurs as a result of a fall on outstretched arm or forearm area.

Rarely occurs superior dislocation, which results from direct blow on the forearm area or strong muscle contraction. When the pectoralis major muscle is fixed, the greater tubercle of the humerus is torn off. Dislocation can be posterior, when the bone moves posteriorly.

Symptoms

Habitual dislocation of the humerus has its own symptoms that allow it to be diagnosed. Often the head and torso tilt in the direction where the injury occurred, with a healthy brush the person supports the area of ​​the forearm on the injured side. The shoulder area drops down, moves anteriorly, and the configuration of the shoulder joint changes. The area of ​​the elbow and forearm is removed from the body.

If you measure the axis of the humerus, it passes by the joint fossa, the deviation occurs anteriorly and in the middle. When palpating the articular cavity, a void is detected there, and the head of the bone is not in its position after the injury. You can find the head of the bone using a simple rotation. Active movements are impossible, passive movements are painful, they have a springy character 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, a dislocation may have complications that result in damage to the articular surface of the humerus or the glenoid fossa of the scapula. The area most often affected is the greater tubercle of the humerus. In elderly people, a fracture of the humerus occurs. A dislocation in a child is accompanied by a separation of the growth plate. 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 an injury, an MRI is often ordered. It allows you to understand not only the location of the head, but also the condition of the surrounding soft tissues, and prepare as much as possible for the operation. The image allows you to visualize the place where it hurts the most.

Treatment

It is absolutely forbidden to use exercises for 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 of the tissues that stabilize the joint. The only option that will eliminate the consequences of the injury is surgery. After this, rehabilitation is carried out, which will allow you to return to normal function. Surgical intervention in a child is of particular importance.

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

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

Recovery

An effective adjunct to treating habitual shoulder dislocation is rehabilitation. It is carried out not only in the shoulder area, but also in the forearm. Apply special exercises, which are of particular importance for the child. Rehabilitation is performed only under the supervision of the attending physician; exercises depend on the severity of the surgical intervention and the physical development of the patient. At the same time, exercises are performed for the forearm.

For adults and children, it will be useful to do massage, which also complements rehabilitation. It is performed carefully so that it does not hurt. It is done after the wound has completely healed, it is better if it is done by an experienced specialist.

Physiotherapeutic treatment methods are also used; they can be performed for adults and children. Moreover, through fixation, which lasts for approximately three to six weeks. The required list of procedures can be presented as follows:

1. Electrophoresis. It is performed with the addition of Novocaine and anti-inflammatory drugs. The essence of the technique is to apply direct currents to the site of damage.
2. Diodynamic. The technique is based on the use of alternating currents at the surgical site.
3. Ultrasound. The procedure is performed with or without the use of medications. Anti-inflammatory ointments are often used; using this technique, the active substances penetrate deeper into the tissue.
4. Magnetotherapy. The essence of the technique is to use a magnetic field at the surgical site. With the help of the procedure, tissue trophism and their regenerative ability are improved.
5. Shock wave therapy. Promotes tissue nutrition and restores them after surgery.
6. Ultraviolet irradiation. It is applied to the site of a postoperative wound, promotes recovery, has a bactericidal effect, and 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. Improves blood flow in the shoulder joint.

An excellent addition to rehabilitation treatment would be a visit to the pool. You can perform gymnastics in water, which helps increase range of motion. But you will have to completely abandon sports and other activities. The period for complete restoration of the capsule and ligaments is three to four months, after which gradual loading can be placed on the operated joint.

Habitual dislocation is a rather complex pathology that requires a responsible approach on the part of 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. And there is no guarantee that changes in the joint can be eliminated completely. There is no need to waste time, and if your shoulder often begins to “pop out,” you should consult a doctor and get treatment so that you can then use your shoulder joint normally.

2016-04-16

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

The ankle joint is considered the most vulnerable among others. It is not without reason that the legendary Achilles tendon, which became the cause of the death of the mythical hero, is located here. 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 moves his feet and walks normally. The structure of the ankle joint is quite complex: it contains several bones and a system of cartilage and muscles connecting them. In addition, a network of blood vessels is formed around each joint and nerve plexuses, 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 correct distribution when walking. Therefore it has great importance strength of the ligamentous apparatus, cartilage and bone tissue.

It has its own anatomical boundaries. At the top, the joint is limited by an imaginary line running 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.

The following sections are distinguished in the joint area:

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

Bone elements of the joint

The ankle joint consists of two bones of the lower leg. These are the tibia and fibula. The foot bone, or talus, is also attached to them. The latter is sometimes also called the supracalcaneal.

The lower (distal) ends of the tibia together form a socket into which the process of the talus bone of the foot enters. This connection is a block - the basis of the ankle joint. There are several elements in it:

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

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

On the inner surface there is hyaline cartilage, which, together with the upper surface of the talus, forms the outer gap of the ankle joint.

What does it look like?

The distal surface of the tibia resembles an arch, on the inner side of which there is a process. The anterior and posterior edges of the tibia form two projections called the anterior and posterior malleolus. On outside The fibular notch is located on the tibia, on both sides of which there are two tubercles, and the lateral malleolus is partially located in it. 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 ridge, into medial (inner) and lateral (outer) parts.

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

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

The talus connects the shin bones and the heel bone. It consists of a body, a block and a neck with a head. Using a block, the talus bone is connected to the bones of the lower leg. It is located in the so-called “fork” formed by the distal parts of the tibia. Top part The block is convex, there is a groove on it that corresponds to the crest of the distal epiphysis of the tibia.

The anterior part of the trochlea is slightly wider than the posterior part and passes into the head and neck of the talus. At the back there is a small tubercle with a groove where the long flexor tendon is located thumb.

Ankle muscles

The foot flexor muscles run along the back and outer surface of the ankle joint:

• posterior tibial,
• triceps shins,
• flexor hallucis longus,
• plantar,
• long flexor of all other toes.

The extensor muscles are located in the anterior part of the ankle joint:

• extensor longus thumb,
• anterior tibial,
• extensor longus of the other toes.

The supinators and pronators provide inward and outward movement in the joint. The pronators include the short and long muscles, as well as the third peroneal muscles. To the supinators are the tibialis anterior and extensor pollicis longus.

Ankle ligaments

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

The ligaments of the ankle joint are divided into ligaments of the tibiofibular syndesmosis - between the outer surface of the tibia and the ankle of the fibula, and the outer and inside ankle joint.

1. The ligaments of the tibiofibular syndesmosis are powerful formations that are divided into interosseous, posterior lower tibiofibular, anterior lower tibiofibular and transverse.
   • The interosseous ligament is a continuation of the interosseous membrane, its main purpose is to hold the tibia bones together.
   • The posterior inferior ligament is a continuation of the interosseous ligament and prevents excessive inward rotation.
   • The anterior inferior tibiofibular ligament is located between the fibular notch of the tibia and the lateral malleolus and prevents excessive external rotation of the foot.
   • The transverse ligament is located under the previous one and also prevents the foot from rotating inward.
2. The external collateral ligaments are the anterior and posterior talofibular and calcaneofibular ligaments.
3. The internal collateral 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 through three branches of the blood arteries - the anterior and posterior tibial and peroneal. They branch repeatedly in the joint area. From these, vascular networks are obtained in the ankle area, capsule and joint ligaments.

Venous outflow is represented by a very extensive network of vessels, divided into internal and external networks. They then form the small and large saphenous veins, the 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 follow the course of blood vessels, respectively, the outflow of lymph goes in front and inside parallel to the tibial artery, and outside and behind – the peroneal artery.

IN ankle joint There are branches of such nerve endings as: superficial perioral and tibial nerves, deep tibial nerve and 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 located anterior to the outer ankle. It is also possible to move the foot in and out, as well as plantar flexion and extension of the spot.

The ankle joint is often exposed to various traumatic influences. This leads to ligament ruptures, fractures and separations of the ankles, cracks and fractures of the tibia. Damage to nerve endings and muscles also often occurs.

Bone anatomy of the shoulder joint.
The shoulder joint is a typical ball-and-socket joint formed by the head of the humerus and the glenoid cavity of the scapula. The glenoid cavity of the scapula is a flattened fossa in the shape of a pear or an inverted comma 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° backward from the transverse axis of the elbow joint, and the scapula is rotated at the same angle forward 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 socket up, down, out or in, so that the center of the head of the humerus remains inside it. When this centered position of the head of the humerus in the glenoid cavity is disturbed, there is a danger of dislocation in the shoulder joint.

Clavicle joints.
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 collarbone rotates around its axis and serves as a support for the shoulder joint, since it is the only one that connects upper limb with an axial skeleton. At the same time, the clavicle acts as a spacer, holding the shoulder joint away from the chest for its greatest mobility.

Articular capsule, labrum and ligaments of the shoulder joint.
The capsule of the shoulder joint is the most spacious and loosest of all the 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 is strengthened by several ligaments: the coracobrachial and three articular-brachial ligaments: upper, middle and lower. There are anatomical variations in the shape and relative position of the articular lip and ligaments: for example, there is an opening between the anterior superior part of the articular lip and the edge of the articular cavity of the scapula, connecting the articular cavity with the subtendinous bursa of the subscapularis muscle. Some of these anatomical variations are particularly predisposing to shoulder injuries.

The labrum not only serves as an attachment point for the articular capsule and its constituent ligaments, but also enlarges the articular cavity, deepening the articular fossa by approximately 1.5 times. By raising the edges of the glenoid cavity, it acts as an additional support for the head of the humerus, preventing it from slipping out. After removal of the labrum, the shoulder joint largely loses its ability to withstand forces that move 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, teres minor and subscapularis - form the so-called muscle capsule of the shoulder joint, or rotator cuff. The supraspinatus muscle starts from the walls of the supraspinatus fossa, goes outward, filling it, passes under the acromion and attaches to the greater tubercle of the humerus, simultaneously fusing the fibers of its tendon with the posterior surface of the capsule of the shoulder joint. It is involved in abduction of the arm to its maximum angle, and its paralysis in suprascapular neuropathy reduces the force of abduction by almost half. The infraspinatus and teres minor muscles begin from back surface The scapulae are below its spine and are attached to the posterior surface of the greater tubercle of the humerus under the insertion of the supraspinatus muscle. Their joint action is to extend and externally rotate the shoulder. Together, these two muscles provide approximately 80% of the total external rotation force of the adducted shoulder. The infraspinatus muscle is more active when the arm is lowered, and the teres minor muscle is more active when the arm is raised 90°. The subscapularis muscle is the only anterior part of the rotator cuff; it starts from the anterior surface of the scapula, attaches to the lesser tubercle of the humerus and carries out its internal rotation, and if the arm is moved to the side, it brings the arm to the body, while simultaneously deflecting it forward. The subscapularis tendon is woven into the joint capsule and strengthens the shoulder joint at the front.

The deltoid muscle is the largest muscle in the shoulder girdle. Anatomy: Beginning in three bundles from the clavicle, acromion and spine of the scapula, it surrounds the shoulder joint and descends along the humerus, where it attaches to the deltoid tuberosity halfway to the elbow joint. Front end deltoid muscle bends the arm at the shoulder joint and, together with the middle part, abducts the arm, and rear end muscles extend the arm. The deltoid muscle is capable of abducting the arm to the maximum angle even without the participation of the supraspinatus muscle, and its paralysis due to neuropathy of the axillary nerve halves the force of arm abduction.

Big teres muscle starts from the lower angle of the scapula and attaches to the crest of the lesser tubercle of the humerus behind the insertion site latissimus muscle backs. Adjacent to it are the axillary nerve and the posterior circumflex artery of the humerus, which pass through a quadrilateral foramen bounded by the teres major muscle below, the teres minor muscle above, the long head of the triceps brachii muscle from the inside and the humerus from the outside. Together with the latissimus dorsi muscle, the teres major muscle extends the shoulder, rotates it inward and brings it to the body.

Muscles of the chest and back. The pectoralis major muscle begins in two wide parts: the clavicular and sternocostal, separated by a groove, and narrows towards the shoulder, attaching to the crest of the greater tubercle of the humerus with lower bundles higher than the upper ones. Due to their strength, it and the latissimus dorsi muscle strengthen the shoulder joint, but they can also contribute to dislocation in it. It has been shown that with horizontal abduction of the arm, the lower bundles of the sternocostal part of the large pectoral muscle are stretched to the limit, and since anterior subluxations of the shoulder arise, in particular, from a sharp horizontal abduction of the arm, it is possible that the immediate 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 muscle originate from the scapula. The short head starts from the coracoid process of the scapula by a common tendon with the coracobrachialis muscle. The long head begins just above the edge of the glenoid cavity of the scapula - from the supra-articular tubercle and the posterosuperior part of the articular labrum; 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 unite into a long muscular belly, which is attached to the tuberosity of the radius. Thus biceps The shoulder gets the opportunity to act on both the shoulder and elbow joints. It is well known that she bends her arm in elbow joint and rotates the forearm outward. It was also assumed that, by contracting, it pulls the head of the humerus down, but recent electromyographic studies cast doubt on this, since the electrical activity of the biceps brachii muscle almost does not increase if there is no movement in the elbow joint. However, this does not mean that the biceps brachii muscle cannot strengthen the shoulder joint with its strong tendon, both at rest and during tension during flexion of the forearm.

Blood supply and innervation.
The blood supply to the muscles of the shoulder girdle occurs almost entirely through the axillary artery and its branches. It crosses the axillary cavity, running 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 anteriorly 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 muscles of the shoulder girdle are innervated by the brachial plexus nerves. 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 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 wall of the chest. According to the places of its beginning, the clavicular part begins 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; abdominal part (weakly expressed), starts from the anterior wall of the rectus abdominis vagina. The bundles of parts of the pectoralis major muscle, noticeably converging, 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 muscle, forms the anterior wall of the axillary cavity and limits the lower edge axillary fossa. The muscle lowers the raised arm and leads it to the body, while simultaneously turning it inward. If the arm is strengthened in an upward position, it lifts the ribs and sternum (auxiliary respiratory muscle), promoting 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. Going 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, promoting expansion of the chest.

Subclavius ​​muscle small in size, occupies the slit-like space between the 1st rib and the collarbone. It starts from the cartilage of the 1st rib, passes in the lateral direction and attaches 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 muscle wide, quadrangular, adjacent to chest on the side, forms the medial wall of the axillary cavity. It begins with large teeth from the upper eight to nine ribs and attaches to the medial edge and lower corner of the scapula. Its upper and middle bundles lie horizontally, the lower ones are oriented obliquely and run from front to back and from bottom to top. The lower 4-5 teeth of the serratus anterior muscle, where they begin, extend between the teeth of the external oblique abdominal muscle. The muscle moves the scapula, especially its lower corner, forward and laterally; the inferior bundles promote 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 strengthened scapula, the anterior serratus muscle raises the ribs, promoting expansion of the chest.

shoulder joint,articulatio humeri , formed by the head of the humerus and the glenoid cavity of the scapula.

The articular surface of the head of the humerus is spherical, and the glenoid cavity of the scapula is a flattened fossa. The surface of the head of the humerus is approximately 3 times larger than the surface of the glenoid cavity of the scapula. The latter is complemented by the articular labrum, labrum glenoidale.

The joint capsule has the shape of a truncated cone. The upper part of the joint capsule is thickened and forms the coracobrachial ligament, lig. coracohumerale, which begins at the outer edge and base of the coracoid process of the scapula and, passing outward and downward, is attached to the upper part of the anatomical neck of the humerus.

The capsule of the shoulder joint is also strengthened due to the fibers of the tendons of adjacent muscles woven into it (vol.supraspinatus, infraspinatus, teres minor, subscapularis).

The synovial membrane of the articular capsule of the shoulder joint forms two permanent protrusions: the intertubercular synovial sheath and the subtendinous bursa of the subscapularis muscle.

In terms of the shape of the articular surfaces, the shoulder joint is a typical ball-and-socket joint. Movements in the joint are performed around the following axes: sagittal - abduction and adduction of the arm, frontal - flexion and extension, vertical - rotation of the shoulder together with the forearm and hand outwards and inwards. Circular movement is also possible in the shoulder joint.

X-ray examination of the shoulder joint

the head of the humerus, the glenoid cavity of the scapula and the x-ray gap of the shoulder joint are visible.

The shoulder muscles are divided into two groups - the anterior (flexors) and the posterior (extensors).

The anterior group consists of three muscles: the coracobrachialis, biceps brachii and brachialis; posterior - triceps brachii and olecranon.

These two muscle groups are separated from each other by the plates of the shoulder's own fascia: on the medial side - medial intermuscular septum shoulder, with lateral - lateral intermuscular septum of the shoulder

Coracobrachialis muscle

m. coracobrachialis. Function: bends the shoulder at the shoulder joint and brings it to the body. Innervation: m. musculocutaneus. Blood supply: aa. Circumflexae anterior et posterior humeri.

Double-headed muscle shoulder, m. biceps brachii. Function: flexes the shoulder at the shoulder joint, flexes the forearm at the elbow joint. Innervation: n. musculocutaneus. Blood supply: aa. collaterale ulnares superior et inferior, a. brachialis, a. reccurens radialis.

Brachialis muscle, m. brachialis. Function: flexes the forearm in the elbow joint. Innervation: n. musculocutaneus. Blood supply: aa.collaterale ulnares superior et inferior, a. brachialis, a. reccurens radialis.

Triceps brachii muscle, m. triceps brachii, Function: extends the forearm at the elbow joint, the long head acts on the shoulder joint, participating in extension and adduction of the shoulder to the body. Innervation: n. radialis. Blood supply: a. circumflexa posterior humeri, a. profunda brachii, aa, collatera

Muscles acting on the joints of the shoulder girdle

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

Pectoralis major muscle- a massive, fan-shaped muscle that occupies a significant portion of the anterior wall of the chest. 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 rectus sheath and is attached to the crest of the greater tubercle of the humerus.

The function of this muscle: lowers the raised arm and brings it to the body, while simultaneously turning it inward. If the arm is strengthened in an elevated position, it lifts the ribs and sternum, promoting 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, promoting expansion of the chest.

Subclavius ​​muscle- occupies the space between the first rib and the collarbone.

The function of this muscle is to pull the collarbone down and forward.

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

The function of this muscle: moves the scapula forward and outward (laterally); rotates the scapula, causing the arm to rise above the horizontal.

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