Anatomy of shoulder joint
The shoulder complex, composed of the clavicle, scapula and humerus, is an
intricately designed combination of four joints, the glenohumeral joint, the
acromioclavicular joint, the sternoclavicular joint, and a floating joint, known
as the scapulothoracic joint.
The glenohumeral, acromioclavicular and sternoclavicular joints link the upper
extremity to the axial skeleton at the thorax. The scapulothoracic joint allows
for the scapula to glide over the contours of the posterior thoracic wall. All four
joints work collectively together to achieve normal shoulder girdle movements.
Movements of the shoulder complex represent a complex dynamic
relationship between muscle forces, ligament constraints and bony
articulations.
, The shoulder demonstrates a unique functional balance mobility and stability
through active forces, known as dynamic stabilization, which is the reliance on
dynamic muscular control rather than passive stabilization through passive
forces such as articular surfaces, capsule, or ligaments.
Osteology
The osseous segment of the shoulder complex comprise of the clavicle,
scapula, the humerus and the sternum.
Clavicle
The clavicle is located between the sternum and the scapula, it connects to the
body through humerus. The clavicle is the first bone in the human body to
begin intramembranous ossification directly from mesenchyme during the fifth
week of fetal life. Similar to all long bones the clavicle has both medial and
lateral epiphysis. The clavicle is convex medially and concave laterally, which,
allows the clavicle to serve as the strut for the upper extremity.
Scapula
The scapula commonly referred to as the shoulder blade is a highly mobile,
flat, thin, triangular shaped bone placed on the postero-lateral aspect of the
thoracic cage. It has two surfaces, three borders, three angles and three
processes.
The shoulder complex, composed of the clavicle, scapula and humerus, is an
intricately designed combination of four joints, the glenohumeral joint, the
acromioclavicular joint, the sternoclavicular joint, and a floating joint, known
as the scapulothoracic joint.
The glenohumeral, acromioclavicular and sternoclavicular joints link the upper
extremity to the axial skeleton at the thorax. The scapulothoracic joint allows
for the scapula to glide over the contours of the posterior thoracic wall. All four
joints work collectively together to achieve normal shoulder girdle movements.
Movements of the shoulder complex represent a complex dynamic
relationship between muscle forces, ligament constraints and bony
articulations.
, The shoulder demonstrates a unique functional balance mobility and stability
through active forces, known as dynamic stabilization, which is the reliance on
dynamic muscular control rather than passive stabilization through passive
forces such as articular surfaces, capsule, or ligaments.
Osteology
The osseous segment of the shoulder complex comprise of the clavicle,
scapula, the humerus and the sternum.
Clavicle
The clavicle is located between the sternum and the scapula, it connects to the
body through humerus. The clavicle is the first bone in the human body to
begin intramembranous ossification directly from mesenchyme during the fifth
week of fetal life. Similar to all long bones the clavicle has both medial and
lateral epiphysis. The clavicle is convex medially and concave laterally, which,
allows the clavicle to serve as the strut for the upper extremity.
Scapula
The scapula commonly referred to as the shoulder blade is a highly mobile,
flat, thin, triangular shaped bone placed on the postero-lateral aspect of the
thoracic cage. It has two surfaces, three borders, three angles and three
processes.
