Latissimus dorsi muscle

Latissimus dorsi
Latissimus dorsi originates from the mid to lower back
Muscles connecting the upper extremity to the vertebral column.
Details
Origin	Spinous processes of vertebrae T7-L5, thoracolumbar fascia, iliac crest, inferior 3 or 4 ribs and inferior angle of scapula
Insertion	Floor of intertubercular groove of the humerus
Artery	Thoracodorsal branch of the subscapular artery
Nerve	Thoracodorsal nerve (C6, C7, C8)
Actions	Adducts, extends and internally rotates the arm when the insertion is moved towards the origin. When observing the muscle action of the origin towards the insertion, the lats are a very powerful rotator of the trunk.
Antagonist	Deltoid and trapezius muscle
Identifiers
Latin	musculus latissimus dorsi
TA98	A04.3.01.006
TA2	2231
FMA	13357
Anatomical terms of muscle [edit on Wikidata]

The latissimus dorsi (/ləˈtɪsɪməs ˈdɔːrsaɪ/) is a large, flat muscle on the back that stretches to the sides, behind the arm, and is partly covered by the trapezius on the back near the midline.

The word latissimus dorsi (plural: latissimi dorsi) comes from Latin and means "broadest [muscle] of the back", from "latissimus" (Latin: broadest) and "dorsum" (Latin: back). The pair of muscles are commonly known as "lats", especially among bodybuilders.

The latissimus dorsi is responsible for extension, adduction, transverse extension also known as horizontal abduction (or horizontal extension),^[1] flexion from an extended position, and (medial) internal rotation of the shoulder joint. It also has a synergistic role in extension and lateral flexion of the lumbar spine.

Due to bypassing the scapulothoracic joints and attaching directly to the spine, the actions the latissimi dorsi have on moving the arms can also influence the movement of the scapulae, such as their downward rotation during a pull up.