Terminology for parts of the leg
The lower leg is anatomically called the crus1 and you can refer to the area above the knee as the thigh.


Sural refers to the calf region of the crus, while Peroneal refers to the side of the leg2.
The front (anterior) side of the crus is called the shin.


Patellar and Popliteal refer to areas associated with the front and back of the knee, respectively2. 

You can see a summary of regional leg and other body terms here. (Below is a chart from the site):

 

Alternatively, you can refer to the regions of the leg using relative anatomical directional terms:





 Sources: 
 1. Wikipedia; 
 2. Rutgers