Name

# Scapula

Pronunciation

(skap-yu-la)

Notes

The scapula, or shoulder blade, is the bone that connects the humerus (arm bone) with the clavicle (collar bone).

The scapula forms the posterior part of the shoulder girdle. In humans, it is a flat bone, roughly triangular in shape. It has two surfaces, three borders, and three angles.

The anterior (front) side of the scapula shows the fossa subscapularis (subscapular fossa) to which the subscapularis muscle attaches.

The posterior surface of the scapula is divided by a bony projection, the spina scapulae (opposite to the fossa subscapularis) into the supraspinous fossa and the infraspinous fossa. This projection is called the spine of the scapula. It begins flat at the base of the shoulder bone, ascends in distal direction for all animals but carnivores and humans to its peak at about the middle of the scapula, this peak is called tuber scapulae. After this peak the spina scapulae steeply decays in height. For humans and carnivores and bovinae the spina runs into a forward pointing hook called acromion, which continues past the main part of the bone.

Another hook-like projection comes off the lateral angle of the scapula, and is called the coracoid process. The end of this hook is the site of attachment of many muscles, such as the coracobrachialis muscle.

Near the base of the coracoid process, so also on the lateral angle, there is a depression called the glenoid cavity. This forms the socket that the head of the humerus articulates with.

The scapula also articulates with the clavicle, via the acromion process (the acromioclavicular joint).