Dorothy FarrarShoulder joint
The shoulder joint is the most mobile ball and socket joint in the body, formed by the scapular socket and the humeral head . This joint is mainly secured by the muscles , which can also lead to tendon or muscle tears or dislocations very often.
Definition
The shoulder blade and upper arm are connected by the shoulder joint. The joint is surrounded by a joint capsule. It has only a few ligaments and is mainly secured by the so-called rotator cuff.
Anatomy
The head of the humerus is connected to the articular surface of the scapula. This has the shape of a plate and is flat, the surface is relatively narrow at the top, whereas it gets wider towards the bottom. The head of the humerus is not completely enclosed by the articular surface.
There is a so-called socket lip between the two joint partners, which increases the contact area. The head of the humerus forms an angle of about 20 to 30 degrees with the shaft of the humerus. In addition, the shoulder joint has a joint capsule that is quite extensive.
The numerous bursae also play an important role in the functioning of the joint . The so-called bursa subtendinea musculi, which reduces the friction between the shoulder blade and the tendon, is located under the subscapularis muscle. Under the process of the acromion lies the bursa subcoracoidea, which represents a kind of reserve space and communicates with the articular cavity. Bursa subdeltoidea and brusa subacromialis ensure the abduction (spreading movement) of the arm.
The shoulder joint also has four ligaments, which are secured by enclosing muscles, which are also known as the rotator cuff. In addition, the joint is stabilized by the tendon of the pectoralis major muscle, the deltoid muscle and the biceps brachii muscle.
Function
Since the shoulder joint is a ball and socket joint, the arm can be moved in all three axes and planes. The two partial joints of the shoulder girdle also contribute to mobility . Overall, the joint has three degrees of freedom. This allows the arm to be moved backwards or forwards in the shoulder, which is known as retroversion.
In addition, it is possible to close or spread the arm (adduction or abduction) and rotate it outwards or inwards (external/internal rotation). The rotator cuff also has an important function, as it enables the arm to rotate in the shoulder joint. This soft tissue coat is very essential for the stability and mobility of the upper arm and shoulder.
Therefore, to diagnose injuries or illnesses in this area, nuclear spin or ultrasound is also used, since the soft tissues can only be displayed with the help of this method.
Diseases
- shoulder dislocation
- Bankart lesion
A very common injury to the shoulder joint is the so-called shoulder dislocation, in which the head of the humerus jumps out of the joint socket and then has to be adjusted. However, a so-called habitual dislocation can also arise from an initial dislocation if the joint is unstable. Anomalies or incorrect innervation of the muscles can also lead to a shoulder dislocation.
The cartilage or the underlying bone can also be injured by recurring dislocations, which is also known as the Hill-Sachs lesion. Arthrosis of the shoulder joint, which is caused by wear and tear of the cartilage, is also quite common. Those affected then suffer from severe pain or limited mobility . In some cases, a shoulder prosthesis is also used.
If connective tissue is pinched, the so-called impingement syndrome occurs, whereby impairments occur when rotating or spreading the arms.
A stiff shoulder or frozen shoulder is when both shoulders or one shoulder are stiff. This is temporary and causes severe pain and restricted movement. If the so-called cartilaginous lip tears off, the symptoms are referred to as a Bankart lesion, which is mainly the cause of a habitual dislocation.
Inflammation of the bursa is also possible. This inflammation is caused by infection or trauma, but also occurs in the context of metabolic diseases such as gout or rheumatoid arthritis . Bursitis is treated with glucocarticoid injections, physiotherapy exercises and non-steroidal anti-inflammatory drugs . If conservative treatment fails, the bursa often has to be surgically removed.
A so-called “calcified shoulder” is also very painful, whereby calcium deposits form in the tendons of different muscles. Those affected then have problems lifting their arm and pain when pressure is exerted on the tendons.
A degenerative change in the articular cartilage is referred to as omarthrosis. It is usually the result of injuries to the joint, with night pain and pain caused by movement occurring in particular. Also very common is tendinitis of the biceps, which is mainly caused by signs of wear and tear.
Hello and welcome to my Health Guide & Encyclopedia! My name is Dorothy Farrar, and I'm the founder and main author of this platform.
My passion for health and wellness started at a young age when I became interested in the connection between the food we eat and the way we feel. This fascination led me to study nutrition and dietetics in college, where I learned about the importance of a balanced diet and the impact of various nutrients on the body.