This is the name given to the two muscles located on either side of the upper and middle back, and if developed give the upper body a triangular shape.
The Latin name means 'broad' (latus) 'back' (dorsum).
The latissimus dorsi extends and laterally rotates the upper arm.
The muscle originates in the processes of the middle and lower spine and ilium, and inserts into the inner edge of the humerus.