Rhomboidei

Rhomboidei refers to the pair of muscles known as the rhomboideus minor and rhomboideus major, located in the upper back beneath the trapezius. They lie along the medial border of the scapula and act to position the shoulder blade during upper limb movements.

Rhomboideus minor originates from the spinous processes of C7 and T1 and inserts on the medial border of the scapula at the level of the scapular spine. Rhomboideus major originates from the spinous processes of T2 to T5 and inserts along the medial border of the scapula from the spine to the inferior angle. The rhomboids are deep to the trapezius and are positioned to influence scapular motion and stability.

Innervation is via the dorsal scapular nerve, derived primarily from the C5 ventral ramus. Blood supply is typically through the dorsal scapular artery; in some individuals, vascularization may arise from branches of the subclavian or transverse cervical arteries.

The primary actions of the rhomboidei are to retract (adduct) the scapula, elevate it, and assist in downward rotation of the scapula, thereby stabilizing the shoulder girdle during arm movements. They function in concert with the trapezius and serratus anterior to maintain proper scapular orientation and facilitate smooth arm elevation and rotation.

Clinical relevance is largely related to acute or chronic strain, overuse, or poor posture, which can lead to upper back or neck pain and altered scapular kinematics. Understanding the rhomboidei is important in assessments of shoulder mechanics and in rehabilitative planning for shoulder or thoracic injuries.