Back

It is one of the most complex muscle. Divided into several area and commonly know as upper and lower back.  

Anatomy

Trapezius - upper/ middle back
Latissimus dorsi - lats of wings of the back
Rhomboid - several muscles of the upper back that help move the shoulder blade

Rhomboid located in the upper back and connects the spine with the shoulder blade. The rhomboid muscle is named due to diamond-like shape. There are two types of rhomboid muscle, the rhomboid major and rhomboid minor which contract and relax to move the shoulder blades. Both of the rhomboid  muscle  sits beneath the trapezius muscle.
 
Trapezius muscle is a triangular muscle which extends from the neck to the mid back and across to cover the shoulder blades. The trapezius muscle can move the shoulder blade in a number of ways beyond the shrug and it is also involved in the rotation of the head and neck.

Teres major and minor. The teres major performs similar actions to the minor although it helps internal rotation and is only active when the shoulder blade is fixed. Teres major responsible for inward rotation and adduction. Whereby teres minor responsible for outward rotation.

Latissimus dorsi are the largest muscle on the back. It attached to the upper end of arm. It is responsible for a number of functions at the shoulder joint. The latissimus dorsi extends the shoulder or draws the arm down toward the body when it is raised to the front.

Recommended exercise

Deadlift
Rowing
Pull up

Tips

• Emphasize on vertical pulling movement like lat pull down or body weight pull up because this will concentrate highly towards the lats muscle.
• Horizontal pulling movement like sited row stimulate middle to upper back.
• To get better stretch on the traps, try shrugging behind the body instead of the side or front.
• Supinate the arm during lat pull down or high row will hit more on the teres muscle and lattisimus dorsi