Scapula bone is located between second and seventh ribs. It is one of the two bones that make up the pectoral girdle. The other being clavicle or collarbone. It consists of the spine, coracoid, acromion process and glenoid cavity.
Scapula is also known as the shoulder blade. It is a part of the pectoral girdle. It provides an attachment site to the head of the humerus and many muscles of shoulder and arms. The main characteristics of the scapula are:
- It is a triangular bone.
- A pair of scapula bones are present in the pectoral girdle.
- It forms the posterior part of the shoulder girdle and situated over the ribs posteriorly covering second to seventh ribs.
- The dorsal surface of the scapula is convex and there is an elevated ridge, which is known as the spine of the scapula. It divides the bone into an upper smaller portion and the lower larger portion known as supraspinous fossa and infraspinous fossa, respectively.
- The spine of the scapula projects laterally forming the acromion process. The clavicle articulates with acromion by acromioclavicular joint.
- The ventral surface is concave and known as subscapular fossa.
- There is a depression in the scapula bone laterally known as the glenoid cavity. The head of the humerus articulates with the glenoid cavity by the glenohumeral joint.
- The hook-like projection present below the clavicle and above the glenoid cavity is known as the coracoid process. It is attached to the clavicle by ligaments.
- Both the scapula bones are not attached to the axial skeleton directly. They are attached to the vertebral column and thorax by muscles, which provides a wider range of movement.
- There are various types of muscles attached to the scapula, which facilitate the different movements of the shoulder.
- The muscles that originate from scapula are biceps, triceps, deltoid, teres minor and major, supra and infraspinatus, etc.
- Trapezius, levator scapulae, serratus anterior and rhomboid muscles, etc. are responsible for the rotation and stabilization of the scapula.
The scapula and clavicle form the pectoral girdle, which connects the upper limb to the axial skeleton.
This was in brief about the Scapula Bone. Get access to all the NEET Questions with explanations, only at BYJU’S.