The shoulder joint, the anatomy of which is discussed in the following article, allows the arms to move freely. Ligaments, on the contrary, limit mobility.
Let's study in detail what the shoulder joint is, the topographic anatomy of which is represented by the mutual arrangement of tissues, nerves and blood vessels.
In the shoulder girdle, the joints unite the clavicle and sternum with the scapula, thereby forming the acromioclavicular and sternoclavicular joints. Let's start in order.
Bones
The anatomy of the human shoulder joint is complex. To provide mobility, the cavity is designed less here, and the range of motion is provided by many tendons and muscles.
The joint consists of two large bones - the humerus and scapula, several joints and many ligaments, tendons and muscles.
The scapula is a flat bone in the form of a triangle. It is also important in building the articulation of the shoulder joint. The bone is located on the back of the body and is easily felt under the skin. It has an articular cavity, to whichthe humerus is attached.
On the back of the scapula there is an axis dividing it in two, where the infraspinatus and supraspinatus muscles are located.
There is another process on the shoulder blade, called the coracoid, that attaches the ligaments and muscles. Another bone - the clavicle - is tubular, with a curved shape.
The whole shoulder joint (anatomy) the photo below illustrates.
Muscles
The rotator cuff, or rotator cuff, is one of the most important muscle articulations in this part. Muscles help adduction, flexion and extension of the arm.
Injuries in this area are most often associated with the cuff. Athletes are at particular risk. However, troubles happen in everyday life, especially when lifting weights and carrying loads without distributing the weight correctly. When the muscles are damaged, the anatomy of the shoulder joint is disturbed. The muscles then cannot contribute to the movement as they used to, and the amplitude is drastically reduced.
So, the cuff consists of:
- supraspinous;
- infraspinatus small round;
- subscapularis.
Blood supply and innervation
The muscles of the shoulder girdle receive blood from the axillary artery and its branches. It crosses the armpit cavity and moves from the first rib to the bottom of the pectoralis major muscle, passing into the brachial artery. A vein accompanies her.
Innervation is realized through the nerves of the brachial plexus. Both spinal and those coming from the anterior branch of the thoracic nerve take part in it. Brachial plexusoriginates from the base of the neck, moves forward and down, penetrating the armpit cavity, goes under the collarbone, under the coracoid process of the scapula, giving off nerves there.
Due to what is the movement?
The shoulder joint can move due to the following five joints (three joints and two - muscular-tendon plan):
- Shoulo-scapular joint.
- Bag education.
- Moving the scapula across the chest.
- Acromioclavicular joint.
- Sternoclavicular joint.
Look at the photo. Here is the shoulder joint: structure, anatomy. The complex structure of this area is best understood by examining the image.
To ensure full movement, all five joints must work smoothly and correctly. Any violation cannot be replaced by other joints. That is why pain and limitation of movement always accompany damage to this area.
Acromioclavicular joint
The anatomy of the shoulder joint is characterized by multiaxiality and a plane, due to which the clavicle merges with the scapula. It is held by a strong coracoclavicular ligament, which runs from the coracoid process of the scapula to the bottom of the clavicle. The scapula is able to rotate around the sagittal axis, which passes through the joint, and also move slightly around the transverse and vertical axes. It turns out that movements in this joint can be made around 3 axes. However, the amplitude here is very small.
Sternoclavicular joint
The anatomy of the shoulder joint is also multiaxial and flat here. The surface consists of the sternal part of the clavicle and the clavicular notch of the sternal manubrium. The shape of the surface of the joints resembles a saddle. Between them is a disk that fuses with the capsule and divides the joint cavity in two. The thin capsule is attached by ligaments woven into the fibrous membrane on both sides. In addition, there is an interclavicular ligament that connects the sternal ends of the clavicles, as well as a costoclavicular ligament, located in a lateral position a little distance from the joint.
The anatomy of the shoulder joint is represented by three axes. It has a rather limited range. Therefore, you can move them forward, backward and rotate a little. A circular motion can be made when the end of the collarbone makes an ellipse.
Scapula Ligaments
In addition to the joints, there are fibrous bundles on the girdle of the upper limbs - these are the ligaments of the scapula. They consist of the lower and upper transverse, as well as the coraco-acromial. The latter is presented in the form of a triangle, where the vault is stretched over the shoulder joint between the coracoid process and the apex of the acromion. The ligament serves to protect the shoulder joint and, together with others, limits mobility during shoulder abduction. The inferior transverse ligament is located between the edge of the glenoid cavity of the scapula and the base of the process of the shoulder, and the superior transverse ligament is thrown over the scapular notch.
Structure and ligaments of the shoulder joint
In the free part of the limb, the joints are fused together andbelt of the upper limb, due to which the wrist, elbow, shoulder and other areas are formed.
The shoulder joint has a multiaxial and spherical structure. It consists of the head of the bone and the cavity of the scapula. The surface of the first is spherical, and the second has the form of a hole. The head is about three times the size of the cavity, which is complemented by the lip of the joint. The latter slightly increases its surface, adding depth, curvature and congruence.
The joint capsule is large but thin. It originates at the lip and is attached to the neck of the humerus. Inside, the capsule is thrown between the tubercles of the humerus and forms the intertubercular synovial sheath. The capsule is fixed by the coracobrachial ligament, directed from the process of the scapula and woven into it.
Movement Features
In the ligament of the shoulder joint, the anatomy is characterized by underdevelopment. Due to the considerable difference in the contact surfaces in the shoulder joint, a large amplitude of movement is possible about three axes: vertical, sagittal and transverse. Around the sagittal, the shoulder is abducted and adducted, around the transverse - it flexes and unbends, and the vertical - turns in and out.
In addition, the anatomy of the shoulder joint allows for circular movements. They in this area can occur together with the girdle of the upper limb. As a result, it is able to describe, to a greater or lesser extent, a hemisphere. But moving it above the horizontal level stops the large tubercle of the humerus.
You need to know that the abduction of the arm, thanks to the work of only the humerus and the articular cavity, is only brought up to ninety degrees. Then the scapula begins to help the movement, due to which the abduction increases to 180 degrees.
Not only problems in the muscles and tendons of this area lead to destabilization of the upper limb. They can be caused by deformity of the chest or disorders in the spine. Therefore, it is so important to be attentive to your he alth and pay attention to emerging symptoms in a timely manner. Then it will be possible to maintain he alth and full movement for life.
Diseases and anatomy of the shoulder joint, MRI
If you have shoulder pain, you should definitely consult a specialist to make the correct diagnosis. The state of the bones will help to find out the x-ray. Soft tissue and cartilage are examined after ultrasound. An excellent and safe way is MRI. The anatomy of the shoulder joint can also be viewed with the help of arthroscopy, which, in addition to diagnosing, also treats the patient.
Let's look at the most common diseases.
Bursitis
The disease is diagnosed with inflammation of the torsion of the synovial bag of the shoulder joint. The anatomy in this part is very complex. Usually the lesion occurs between the bone and the tendon. A feature of shoulder joint bursitis is that the synovial bursa does not communicate with its cavity.
Causes of bursitisthere can be both injuries and infections, as well as excessive stress on the joint in athletes and workers engaged in heavy physical labor.
Shoulohumeral periarthrosis, or periarthritis
This is also a common condition for shoulder pain. This includes a whole group of the following diseases.
- Osteochondrosis develops in the cervical spine. The pain spreads through the nerves and goes to the brachial plexus. Then the so-called plexitis develops. The treatment method is chosen depending on the condition of the nerve endings, as well as the intervertebral discs.
- Subacromial impingement - a syndrome characterized by compression of the shoulder rotators that pass between the head of the shoulder and the process of the scapula. The channel may be compressed or injured. Then the person will feel pain, especially at night. He will not be able to lie on his shoulder, bend his arm and take it to the side. During treatment, anti-inflammatory drugs are selected, and physiotherapy is also prescribed. Ointments, massage, compresses and gymnastics are used. If necessary, a surgical operation is also prescribed.
- Rupture of the cuff occurs as a result of trauma, squeezing or stretching. The tendon frays. The shoulder begins to ache, and the pain radiates to the arm, which makes it impossible to bend and remove it. When the tendon is torn, surgery is required, where the tendons are sewn together through arthroscopy. In this case, the main thing is not to miss the optimal time, the result will be the better, the sooner the problem is clarified and eliminated.
- When the joint capsule sticks together during inflammation, it is diagnosedadhesive capsulitis. The patient is less able to move his arm. If arthroscopic surgery is not performed, then in the future the only option to restore mobility will be prosthetics.
- Due to chronic strain of the muscle and tendon under the shoulder blade, as well as injury, the "frozen shoulder" syndrome develops. At the same time, pain and limitation or inability to take the arm outward are felt. To save the patient from suffering, the affected area is injected with an anesthetic.
- Due to trauma, the cartilaginous lip can be damaged and ruptured. Recovery is possible with arthroscopy.
Prosthetics
To replace surfaces destroyed by injury or disease, a shoulder joint is prosthetized. The anatomy of the glenoid cavity remains unaffected. An artificial implant is installed only in cases where other methods of treatment are ineffective.
So, it becomes the only solution after a fracture, when the anatomy of the shoulder joint and shoulder muscles cannot be restored and the metal fixator was useless.
You will also need prosthetics at an advanced stage of osteoarthritis. Cartilage damage is accompanied by pain, crunching and limited movement. Patients become helpless. At the same time, prosthetics restore the work of the hands, and the person gets rid of pain.
The same goes for damage to the rotator cuff muscles. If arthroscopy is an effective method of treatment at the beginning of the disease, then later,in the running version, it will be powerless. Therefore, an implant is installed.
Also dangerous is a severe form of a disease such as rheumatoid arthritis. Joint surfaces are destroyed, rotator cuff muscles and other soft tissues are damaged, severe pain is felt, and movement is limited and gradually leads to immobilization.
Whatever manipulations are performed on the joint, after them the hand must be fixed with an orthosis, bandage or bandage. In order for the functioning of the upper limb to return to normal, complex treatment is carried out, which involves various restorative measures. These include special workouts, massages and physiotherapy.
