LATISSIMUS DORSI (LAT) ⠀ [ANATOMY, FUNCTION & PATHOLOGY] ⠀ The LAT is one of the widest muscles in the human body. It is a very thin triangular muscle that is not used strenuously in common daily activities but is an important muscle in many exercises such as pull-ups, chin-ups and lat pulldowns. ⠀ It has its origins along the thoracolumbar fascia of the lower back, arising from the inferior thoracic and lumbar vertebrae (Spinous proc. T7-L5), sacrum and iliac crest. On its way to the humerus, it usually attaches at the lower 3-4 ribs and the inferior angle of the scapula. It runs obliquely, superiorly and laterally through the back and armpits to insert anteriorly on the humerus, at the medial lip of the bicipital groove. ⠀ The LAT has several different functions, all of which involve movements of the arm. The primary function of the lat is the adduction of the arm, which is often used when performing a pull-up or chin-up or when pulling a heavy object down from a shelf above one’s head. Another function of the lat is extension of the arm, as in swinging the arm toward the back. This motion is used when swinging the arms while walking as well as during rowing exercises. Finally, the LAT medially rotates the arm, moving the front of the arm towards the body’s midline. It also plays a role in extension and lateral flexibility of the lumbar spine and has an impact on pelvic positioning! ⠀ When this muscle becomes too tight, the opposite movements, from the ones listed above, can become inhibited. When this happens, the body's natural response is to compensate so the desired movement can be accomplished. Injury and misalignments like rounded shoulders or wrong positioning of lower back and pelvic occur when our body has to make these compensations. ⠀ Having trouble with your overhead lifts? Experiencing shoulder pain, back pain, even wrist pain when attempting these lifts? Tight LATS could be part of the issue! ⠀ Additionally LAT trigger points can lead to referred pain in the shoulder, chest or arm as you can see on the red marked zones in picture 3.