Lower Arm

Elbow – the elbow is the joint on which the upper and lower arms join. It's rotation is approximately 180 degrees between up and down and 90 degrees between side to side. It's joint complexion isn't just like the shoulder with some noticeable differences mainly in where the muscles come and attach to the bones. It's arguably one of the few joints in the body where the bones sit one atop the next with only a small cup or cartilage between that curves in both directions forming what's called a concave shape in the middle. It's function is to provide cushion and support for the movements which follow. Without it, movement would be incredibly painful and thin. The muscles also come and support the upper and lower arms over this joint in thin portions known as a tendon. That's why you don't see as many muscles appearing in these places for mostly functional reasons. It's also what you'll see when a lot of muscle builders, while nice to look at, are swole and incredibly stiff on moving around. Any damage to this joint usually requires the arm be attached to the chest in a sling. This limits movement until the event can be over with healing that follows hopefully thereafter.

Ulnus – one of the two twin bones that makes up the lower arm between the wrist and the elbow. Without knowing it, the two are pretty near joined well together. In fact, it resmembles the shape of the double bones found in the resident chicken that is if you've eaten their wings, only a lot larger of course.

Radius – the other twin bone that makes up the lower arm allowing for structure and function. Basically, it's like a much finer controlled form of the movement. The muscles are also much naturally thinner except in cases of swelling and illness in which the arm takes on a somewhat swollen appearance. Veins in this area are also much larger and closer to the skin especially right over the wrist, the back of the hand, and where the inner portion of the elbow comes round and folds. That makes these sites ideal for drawing blood in cases of checking lab values of obtaining vascular access. You can identify them by the things appearing blue on the hands.