Muscle, Semispinalis Thoracis (M. Semispinalis Thoracis, Pna)

Muscle, semispinalis pectoralis (lat. Musculus semispinalis thoracis) - muscle of the chest, superficial.

The semispinalis pectoralis muscle begins from the spinous processes of the VII cervical and I-II thoracic vertebrae, as well as from the lateral surfaces of the body and the transverse processes of the II-IV thoracic and I lumbar vertebrae. Then the muscle passes through the intervertebral foramen and attaches to the tubercles of the posterior surface of the XII thoracic vertebra and the spinous processes of the XI-XII thoracic and II-V lumbar vertebrae. At the level of the XII thoracic vertebra, the semispinalis thoracis muscle is attached to the transverse processes of the II-III lumbar vertebrae and forms a junction with the interspinous muscle.

The function of the semispinalis muscle is to extend the spine.

The blood supply to the semispinalis pectoralis muscle is provided by the branches of the transverse artery of the neck and the thoracic aorta. Venous drainage occurs through veins that drain into the superior vena cava.