The Rhomboideus Capitis in Man-Correctly Named Rare Muscular Variation

Abstract

Summary: This is the third original report on the rhomboideus capitis muscle in man, as far as the author is aware. In the earlier descriptions, the muscle was named as the occipito-scapularis and the rhomboideus-occipitalis or capitis. The muscle was situated on the left side of the neck as a muscular band attached cranially to the occipital bone and caudally to the scapula and was closely related to the splenius capitis and the levator scapulae . A revision of previous descriptions and a brief comparative note on the rhomboideus muscle is given.

Rhomboid muscle variations: notes on their naming and classification principles

“…[3] Additional fibers contributing from C3 and C6 spinal nerves were also reported in some studies. [16] Variations of the rhomboids were previously reported as case reports, [9,14,17] or in large series. [4][5][6][7][8]10] One and the same aberrant muscle is named and grouped differently in majority of these reports.…”

“…Interestingly, a muscle also called rhomboid minimus was described in quite a different location; just superior to the rhomboid minor. [12] Another interesting variation reported is the rhomboid capitis (rhomboid occipitalis), [13,14] also named as occipitoscapular muscle. [4,5] Basically, the rhomboid capitis is a common neck muscle in many lower mammals.…”

“…Based on its origin and insertion, the variant muscle slip was identified as rhomboid capitis muscle. [13,14] It had a length of 21 cm and a width of 6-7 mm.…”

Back Muscles

“…Wood (1867a, b) was the first to describe the muscle as arising from the occipital bone at the level of the splenius capitis muscle, immediately deep to the cranial attachment of the trapezius muscle on the superior nuchal line (Figs 30.5,30.18,30.20). Knott (1883), and later Rogawski (1990), found this muscle with cranial attachments to the medial one-third of the superior nuchal line immediately superior to the occipital attachment of the semispinalis capitis muscle. The rhomboid occipitalis muscle then extended inferiorly, passing between the splenius and trapezius muscles to attach to the medial border of the scapula via short tendinous fibers.…”

“…The rhomboid occipitalis muscle (synonyms: rhomboid capitis, rhomboid cervicis, occipitoscapularis) has been reported by several authors (Wood 1867a(Wood , b, 1870Knott 1883;Patten 1935;Rogawski 1990;Bergman et al 2008;Standring 2009). Wood (1867a, b) was the first to describe the muscle as arising from the occipital bone at the level of the splenius capitis muscle, immediately deep to the cranial attachment of the trapezius muscle on the superior nuchal line (Figs 30.5,30.18,30.20).…”