The human skeletal system is the framework on which just about everything else is held together. The bones in your body serve as attachment points for muscles and organs, allowing for protection and easy motion. The scapula is a bone located near the upper back of your shoulder joint. Let's take a look at the basic anatomy of the human scapula.
The scapula is the major bone that connects the humerus to the clavicle. The humerus is the bone in your upper arm, and the clavicle is your collarbone. The scapula is commonly referred to as the "shoulder blade".
The scapula is roughly triangular in shape, although it contains numerous ridges and prominences that make it's shape a bit wonky and very unique as bones go. The scapula serves as an attachment point for a wide range of chest and arm muscles. It is a very hardy bone, and can be very hard to fracture. If you break your scapula, odds are you've suffered a pretty severe chest injury. In fact, the scapula serves to protect the back of the upper chest.
In very general terms, the scapula has three borders; the superior border, the vertebral border, and the axillary border.
The superior border is the upper edge, near the clavicle. This is the shortest of the three borders, and stretches from the medial angle to the coracoid process. If this is confusing without a picture, don't worry, you're not alone.
The vertebral border is closest to the spinal column. It is the longest of the three borders and runs from the medical angle down to the inferior angle.
The axillary border is closest to the armpit and upper arm. It runs from the glenoid cavity (where the humerus attaches) to the inferior angle.
One of the major features of the scapula is the acromion (sometimes called the acromion process). This is a large spine that juts out of the front of the scapula. It is the part of the scapula that forms the connection with the clavicle. The end of the acromion is the acromioclavicular joint, where the acromion meets the clavicle. The acromion is also the bone that you feel if you rub the top and front of your shoulder.
There are more than a dozen muscles that attach to various parts of the scapula. All of them are important in some way, but some of the more "famous" muscles that make attachments to the scapula include the pectoralis minor (a chest muscle), biceps and triceps, trapezius, and deltoid. These are all muscles that are commonly "worked out" to look more muscular. There are also many others with more obscure names, such as the subscapularis, infraspinatus, and serratus anterior (among others).
This is only meant to be an introduction to the anatomy of the human scapula. This is a bone that is highly complex and serves a wide range of functions in the support and protection of the back. In addition, given it's odd shape, it's often easier to understand with the aid of a picture, which can be found in many places on the Internet.