Corpus: Rhomboid minor muscle

The lesser rhomboid muscle is a diamond-shaped muscle that belongs to the middle layer of the secondary back muscles.

The rhomboid minor muscle has its origin at the spinous processes (processus spinosi) of the 6th and 7th cervical vertebrae or at the ligamentum nuchae, according to other authors at the spinous processes of the 7th cervical vertebra and 1st thoracic vertebra.

The fibres run laterally and caudally to the scapula (shoulder blade), where they find their insertion at the medial edge (margo medialis) of the bone at the level of the scapular spine.

The rhomboid minor muscle is innervated by the dorsal scapular nerve, a branch of the brachial plexus (segments: C5, with parts from the neighbouring segments C4 and sometimes also C6).

The rhomboid minor muscle fixes the scapula to the trunk. When contracted, it lifts the scapula cranially and medially. It is supported by the rhomboideus major muscle.