The human shoulder girdle, also known as the pectoral girdle, is a complex structure that connects the upper limbs to the axial skeleton. It consists of two main bones: the clavicle (collarbone) and the scapula (shoulder blade).
Clavicle
The clavicle is a long bone that serves as a strut between the shoulder blade and the sternum or breastbone. It is the only long bone in the body that lies horizontally. Together with the shoulder blade, it makes up the shoulder girdle. It is a touchable bone, and in people who have less fat in this region, the location of the bone is clearly visible, as it creates a bulge in the skin.
capula
The scapula is a flat, triangular-shaped bone that lies in the upper back between the second and seventh rib. It connects the humerus (upper arm bone) with the clavicle. The scapula has two important processes, the coracoid and the acromion. The coracoid process is a small hook-like structure on the lateral edge of the superior anterior portion of the scapula. The acromion process is a continuation of the scapular spine, and hooks over anteriorly.
Joints
The shoulder girdle forms four joints: the sternoclavicular joint (between the sternum and clavicle), the acromioclavicular (AC) joint (between the scapula and the clavicle), the glenohumeral (shoulder) joint (between the scapula and humerus), and the scapulothoracic joint (between the scapula and the posterior thoracic cage).
Functions
The shoulder girdle serves as the anchor that attaches the upper limbs to the axial skeleton. It allows for a large range of motion, mainly in the highly mobile scapulothoracic joint. The shoulder girdle also provides attachment points for many muscles that allow the shoulder and elbow joints to move.
Muscles
The shoulder girdle consists of five muscles that attach to the clavicle and scapula and allow for the motion of the sternoclavicular joint and acromioclavicular joint. These muscles include the trapezius muscle, levator scapulae muscle, rhomboid muscles (major and minor), serratus anterior muscle, and pectoralis minor muscle.
Clinical Notes
Injuries to the shoulder girdle are common due to its mobility. Fractures can occur in the clavicle or the scapula, often as a result of trauma such as a fall or a direct blow to the area.
In conclusion, the shoulder girdle is a complex structure that plays a crucial role in the movement and functionality of the upper limbs. Its unique design allows for a wide range of motion, making it a vital component in many daily activities..
