In medicine, the so-called fornix humeri represents the roof or dome-like structure of the human shoulder. This is composed of different anatomy structures, which describe the acromion, the processus coracoideus and the ligamentum coracoacromiale.
What is the fornix humeri?
The fornix humeri forms a structure of connective tissue and bone called the acromion, and is located above the shoulder joint in the human body. The shoulder joint is composed of the humerus and the scapula. In the upper area, the scapula has two bony processes. These bony processes have a connection of connective tissue. In connection with the intervening ligament, the so-called acromion is formed, which is located above the shoulder joint. The acromion describes a bony protrusion from the so-called scapula. This originates in the spina scapulae and represents the highest area of the scapula. The processus coracoideus describes a bony process of the scapula, in technical language it is called the scapula. The ligamentum coracoacromiale, on the other hand, describes a ligament in the shape of a triangle located between the acromion of the scapula and the processus coracoideus.
Anatomy and structure
The fornix humeri extends cranially over the so-called articulatio humeri, which is the glenohumeral joint. This is delineated above. Between them is a gap containing the subacromial bursa, which controls the movements of the tendons of the biceps brachii muscle and the humeral head. This lies below the coracoacromial arch. The human shoulder is composed of the main joint as well as various secondary joints. These include, for example, the acromioclavicular joint. This refers to the joint surface between the rib cage wall and the shoulder blade. Here, the area between the humeral head and the acromion (fornix humeri) is found. In technical language, it is also referred to as the subacromial space. The main joint is composed of the glenoid cavity and the humeral head, which forms a bony section of the scapula. This joint has the structure of a ball and socket joint and has the greatest possible range and range of motion in the human body. The shoulder has the ability to perform movements effortlessly in all three spatial axes. For this reason, the shoulder is enormously mobile, which means that it can be moved in almost all directions. However, since there are almost no restrictions on movement, the risk of injury in the shoulder area and especially in the area of the fornix humeri is also increased. In addition, an affinity to possibly emerging instabilities of the shoulder as well as signs of wear can be observed.
Function and tasks
The area of the scapula that forms the fornix humeri is called the acromion. All muscles are fixed to the bone there with the help of tendons, and the bones are moved by the individual muscles. For this purpose, the tendons are pulled. The so-called superior facies of the acromion has a rough structure and, like the lateral edge on the acromion, represents the base of the deltoid muscle. The bone is immediately subcutaneous and is used for palpation of the anatomical reference point. In the medial margin, which the acromion has, there is a small oval area. This has the task of establishing the connection between the joint and the clavicle, the collarbone. In technical language, this joint is called acromioclavicular joint. Thus, the acromion, in conjunction with the clavicle, represents a bony base of the shoulder. On the one hand, it serves as a starting point of muscles, and on the other hand, it shows a joint-like connection with the immediately adjacent clavicle. Due to this fact, the shoulder can be rotated in the opposite direction to the clavicle. The acromion consists of different surfaces, mainly the upper area, the so-called facies superior, is a starting point for various muscles in the shoulder area. The upper area, the facies superior and the lateral area, the lateral edge of the acromion, designate the origin of the deltoid muscle. Its other parts originate from other areas of the shoulder. Nevertheless, they have a common attachment, which is the roughened surface of the deltoid tuberosity, the humerus.This muscle has different functions. It is responsible for the shoulder contour and is involved in almost all shoulder movements. However, it mainly serves the lateral abduction movements of the arms. These are referred to in technical language as abduction.
Diseases
Various complaints and diseases can occur in connection with the fornix humeri. The most common are degenerative changes in the shoulder area, which lead to painful tendon and soft tissue impingement in the area below the acromion. In medicine, this is referred to as impingement syndrome. In this clinical picture, the tendons of the rotator cuff, which are located in the subacromial space, become impinged. A synonym for impingement syndrome is the so-called subacromial impingement. This is therefore a bottleneck, which is caused by the entrapment of the tendons of the rotator cuffs below the acromion as well as the bursa subacromialis. In medicine, this bottleneck is counted among the subacromial syndromes. This entrapment causes severe irritation of the subacromial soft tissues. They are located between the humeral head and the acromion. Abduction of the arms in the range of 60 to 120 degrees then results in regular pain. Causes of this discomfort include scapular dyskinesia, osteophyte formation, muscle imbalance, SLAP lesion, and rotator cuff rupture.
