M. Teres Major - Greater rounded muscle

The musculus teres major (latin for "greater rounded muscle“) is a skeletal muscle of the upper arm. It is located in the back body, whereas for quadripedal animals it is located deep and behind the shoulder blade. The muscle creates an axillary space through which several important arteries and veins pass.

Upper Arm

M. Teres Major

Origin
Lower edge of the shoulder blade
(Angulus inferior scapulae)
Insertion
Front side of the humerous
(Crista tuberculi minoris humeri)
Function
Internal rotation, retroversion and adduction of the arm
Innervation
Nervus subscapularis, possibly also the Nervus thoracodorsalis or Nervus axillaris
Spinal Segments
C5, C6