Rhomboideus major

Rhomboid major
Muscles connecting the upper extremity to the vertebral column. Rhomboid major indicated in red.
Details
Origin	spinous processes of the T2 to T5 vertebrae
Insertion	medial border of the scapula, inferior to the insertion of rhomboid minor muscle
Artery	dorsal scapular artery
Nerve	dorsal scapular nerve (C4 and C5)
Actions	Retracts the scapula and rotates it to depress the glenoid cavity. It also fixes the scapula to the thoracic wall.
Antagonist	Serratus anterior muscle
Identifiers
Latin	musculus rhomboideus major
Dorlands /Elsevier	m_22/12550536
TA	A04.3.01.007
FMA	13379
Anatomical terms of muscle []

The rhomboid major is a skeletal muscle on the back that connects the scapula with the vertebrae of the spinal column. In human anatomy, it acts together with the rhomboid minor to keep the scapula pressed against thoracic wall and to retract the scapula toward the vertebral column.

The rhomboid major arises from the spinous processes of the thoracic vertebrae T2 to T5 as well as the supraspinous ligament. It inserts on the medial border of the scapula, from about the level of the scapular spine to the scapula's inferior angle.

The rhomboid major is considered a superficial back muscle. It is deep to the trapezius, and is located directly inferior to the rhomboid minor. As the word rhomboid suggests, the rhomboid major is diamond-shaped. The major in its name indicates that it is the larger of the two rhomboids.

The two rhomboids are sometimes fused into a single muscle.

The rhomboid major, like the rhomboid minor, is innervated by the ventral primary ramus via the dorsal scapular nerve (C5).

Both rhomboid muscles also derive their arterial blood supply from the dorsal scapular artery.

The rhomboid major helps to hold the scapula (and thus the upper limb) onto the ribcage. Other muscles that perform this function include the serratus anterior and pectoralis minor.

Both rhomboids (major and minor) also act to retract the scapula, pulling it towards the vertebral column.

The rhomboids work collectively with the levator scapulae muscles to elevate the medial border of the scapula, downwardly rotating the scapula with respect to the glenohumeral joint. Antagonists to this function (upward rotators of the scapulae) are the serratus anterior and lower fibers of the trapezius. If the lower fibers are inactive, the serratus anterior and upper trapezius work in tandem with rhomboids and levators to elevate the entire scapula.