Rhomboideus thoracis muscle

The thoracic rhomboid muscle (Musculus rhomboideus thoracis) is the thoracic part or the rhomboid muscle, which originates form the spinous processes of the the cranial thoracic vertebrae.

Origin: spinous process of the fourth to seventh thoraci vertebrae 

Insertion: Medial and partly on the lateral edge of the base of the scapula.

Action: To elevate the limb, pull the limb and shoulder forward or backward, to draw the scapula against the trunk.

Nerve: Rami dorsales of the cervicales et thoracicales nerve.

Note : the rhomboid muscle (not listed in the Vth NAV) lies deep to the trapezius muscle and inserts on the medial aspect of the dorsal part of the scapula. It forms the withers region of the animal. In human, the rhomboid muscle is completely divided into two separate muscles, the rhomboid major (equivalent to the thoracic rhomboid muscle in animal) and the rhomboid minor (equivalent to the cervical rhomboid muscle in animal). In animals, the rhomboid muscle is continuous between his different parts:

• The thoracic rhomboid muscle (Musculus rhomboideus thoracis) is the thoracic part or the rhomboid muscle, which originates form the spinous processes of the the cranial thoracic vertebrae.
• The cervical rhomboid muscle (Musculus rhomboideus cervicis) is the cervical part of the rhomboid muscle, which originates form the spinous processes of the the cervical vertebrae.
• The rhomboideus capitis is the capital part of the rhomboid muscle, only present in carnivores, arising form the tendinous raphe of the neck.