The shoulder blades, or scapulae, come as a mirrored pair. These flat, triangular bones are on the posterolateral aspect of the ribcage, sitting overtop of ribs two to seven. The scapula has two surfaces, three borders, three angles, and three processes. Let’s start with the surfaces – front and back.
The front surface can also be called the costal or ventral surface, and it features the subscapular fossa. The back surface is arched and divided in two by the spine, or spinous process, of the scapula. The portion above the spine is smaller and is called the supraspinous fossa. Below it is the infraspinous fossa. Connecting the two fossae is the spinoglenoid notch.
Moving onto the three angles – superior, inferior, and lateral. Note that the superior angle is also known as the medial angle and the lateral angle is also known as the glenoid angle or the head of the scapula, since it’s the thickest part of the scapula. It has the glenoid cavity on its articular surface, which articulates with the head of the humerus. Beneath the glenoid cavity you can find the infraglenoid tubercle.
Now for the three borders – superior, axillary, and medial. The superior border runs from the base of the coracoid process to the superior angle. It is the shortest and thinnest and it is concave. At its lateral part is a deep, semicircular notch – the scapular notch – which is formed partly by base of the coracoid process. The axillary border runs from the inferior angle to just above the lower margin of the glenoid cavity. It is the thickest border. Finally, the medial border runs from the superior angle to the inferior angle. It is the longest border.
Another feature I’d like to point out is the anatomical neck of scapula – a slightly constricted portion that surrounds the head of the scapula. Found medial to the base of the coracoid process, it is more distinct below and behind.
Now for the three processes – the acromion, coracoid process, and the spine of the scapula. The acromion is a large process overhanging the glenoid cavity. The coracoid process has a hook-like shape and sits on the superior anterior portion of scapula. The spine of scapula – as mentioned previously, divides the back surface of the scapula in two.
The scapula is important as it provides attachment points for intrinsic, extrinsic, stabilizing and rotating muscles which allow movement of the upper limb.

3D model from: https://www.turbosquid.com/3d-models/...