Scapulae, commonly referred to as scapulas, are a pair of flat, triangular bones located on the posterior aspect of the upper back in humans. They play a crucial role in the skeletal framework of the shoulder girdle. Each scapula extends from the second to the seventh rib and connects the upper arm bone (humerus) to the clavicle (collarbone) through the acromioclavicular joint.
Measuring approximately 5 to 6 inches in length, scapulae boast several distinctive features. Their anterior surface is concave and presents a shallow, oval depression called the glenoid cavity, which articulates with the head of the humerus to form the shoulder joint. The spine of the scapula, a prominent ridge on the posterior surface, divides it into the supraspinous fossa above and the infraspinous fossa below. Furthermore, the coracoid process, situated on the anterior surface, provides attachment points for various muscles and ligaments involved in shoulder movement and stability.
The scapulae play a vital role in shoulder mobility and stability. They allow for extensive range of motion in the shoulder joint, enabling movements such as abduction, adduction, flexion, extension, and rotation of the arms. In addition, these bones, along with the clavicles, protect the underlying vital structures within the thoracic cavity, including the lungs and heart.
Overall, the scapulae serve as integral components of the musculoskeletal system by providing essential skeletal support, facilitating efficient arm movements, and ensuring the protection of vital organs.
