The shoulder is considered to be one of the biggest supports of the body when it comes to posture and movement. It is also known to be a large structure as it is composed of three different bones. These bones are known as the clavicle or the collarbone, the shoulder blade or the scapula and lastly, though not actually a part, it is greatly connected to the shoulder and it is known as the humerus or the bone of the upper arm. Aside from these three main bones, there are also several tendons, muscles and ligaments that associated with the shoulder. There are also joints of the shoulder known as the glenohumeral joint or the shoulder joint. The shoulder joint is the part of the body where the humerus is firmly attached to the scapula which means that it serves as a connection between the arm and the shoulder.
The Shoulder CartilagesCredit: http://gaortho.com/old_site/index.php?page=JointReplacement
The shoulder joint is also known to have two different kinds of cartilage which are the articular cartilage and the labrum. The articular cartilage is also known as the white cartilage which can be found at the tips of the bones usually at the proximal and distal parts. This facilitates the connection between the bones as they move on each other. The other cartilage is known as the labrum which is more rigid as compared to the articular cartilage. This type of cartilage is only found in the area in which the tips of the bones are attached or the area around the socket of the joint.
The Diverse Functions of The ShoulderCredit: http://shoulderexercises.net/
The shoulder has the huge function because it should be able to support the movement of several parts of the body including the arms and the hands or what is collectively called as the upper limb or upper extremities. Aside from being flexible enough when it comes to movement, the shoulder should also possess a certain stability as it is very important in being able to maintain posture and to perform different actions like pushing and pulling. These diverse and even opposing functions of the shoulder makes it really prone to different problems primarily injuries. There is a contrasting force between its supporting function for the upper limb and its function for stability.
The Shoulder JointCredit: http://www.activemotionphysio.ca/Injuries-Conditions/Shoulder/Shoulder-Anatomy/a~361/article.html
Three different joints can be found on the shoulder and these are the acromioclavicular joint, the glenohumeral joint and the sternoclavicular joint. First of all, the glenohumeral joint is known to be the primary joint that can be found on the shoulder. Being the main joint of the shoulder, it is also called as the shoulder joint. This joint is described to be in a ball and socket structure which is the main reason why the entire arm could be able to perform rotational motion. This joint facilitates and supports the versatility of arm movements. The shoulder joint is formed by the connection between the fossa of the scapula which looks like hole and the head of the humerus which exactly fits in the said area. The two parts forming the shoulder joint are described to be in a ball and socket structure with the ball as the head of the humerus and the socket as the fossa of the scapula or the glenoid fossa. The glenohumeral joint also known as the shoulder joint is enveloped by a capsule. The capsule is a soft tissue that attaches itself to the humerus and the scapula. The capsule is lines with the synovial membrane together by the coracohumeral ligament which strengthens it. There is also what is known as the glenohumeral ligaments that are used to attach the humerus to the scapula. glenohumeral ligaments.Credit: http://www.parkwayphysiotherapy.ca/article.php?aid=372
Another type of joint is known as the sternoclavicular joint which can be found at the middle part of the clavicle near the anterior part of the sternum or the top part known as the manubrium. From the name itself, you can see that this joint is formed as a connection between the sternum and the clavicle. If you are to describe the two bones, the manubrium is actually convex with a greater size as compared to the clavicle which is simply rounded and triangular with a somehow thinner structure. The sternoclavicular joint is made up of a tight capsule which makes sure that the joint is really made stable for movement purposes. This joint is supported by several ligaments as well. When it comes to stabilizing, the costoclavicular ligament is the one responsible for the function. When it comes to increasing the range of motion of the joint, a fibrocartilaginous disc is the one mainly responsible.
Lastly, there is the acromioclavicular joint which is located on the topmost part of the shoulder. Again, like any other joint, you can be able to derive from its name which two parts are the areas that this joint connects. In this case, this joint connects the acromion of the shoulder or the highest point of the shoulder and the clavicle. This joint makes it possible for the arm to be able to move above the head. It also facilitates the movement of the scapula so that the arm could be able to achieve greater rotational motion ability.
There are actually three ligaments that are used to stabilize the acromioclavicular joint and these are known as the acromioclavicular ligament, coracoacromial ligament and the coracoclavicular ligament. The acromioclavicular ligament extends to attach the upper part of the acromion to the upper part of the lateral tip of the clavicle. The coracoacromial ligament extends from the coracoid process to the acromion area. Lastly, the coracoclavicular ligament extends from the coracoid process to the clavicle.
As you can see, the shoulder is related to many different structures primarily involving the upper extremities. With this in mind, you must definitely understand that proper maintenance of the shoulder is important for you to achieve appropriate functioning and posture for your body. You should prevent the shoulder from encountering or handling too much pressure and tension.