Occipital Bone Fossa Associated with the Position of Rectus Capitis Posterior Minor Muscle

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Elisa Marinkovic & Paula Jorquera


Rectus Capitis Posterior Minor muscle (RCPm) is one of the deepest and shorter muscles of the posterior region of the neck. RCPm arises from the posterior tubercle on the posterior arch of atlas and inserts on the squamous part of the occipital bone, inferior to the inferior nuchal line and lateral to the external occipital crest at midline. Based on their anatomical location, and their functional role, is considered to be a head extender muscle and an active element in the stabilization of the occipitoatlantal joint. During routine examination of the skulls, in the Morphology Laboratory of the Basic Biomedical Sciences Department, University of Talca, Chile, two unusual fossas were found in the squamous part of occipital bone, of an adult human skull of masculine sex. No other significant bony anomaly was noted, but it is observed that the elevations and depressions are well marked in the skull. The anatomical location of this fossa suggests a relationship with the RCPm muscle that is described in the same location of this finding. Therefore, it is postulated that prolonged improper posture from an early age, could generate a mechanical compression which would result in the finding fossas; this based on Wolff's law, which states that the bone tissue adapts to the mechanical demands placed on him.

KEY WORDS: Occipital Bone; Fossa; Anatomical variation; Rectus Capitis Posterior Minor muscle; Rectus Capitis Posterior Major muscle.

How to cite this article

MARINKOVIC, E. & JORQUERA, P. Occipital bone fossa associated with the position of rectus capitis posterior minor muscle. Int. J. Morphol., 33(4):1319-1322, 2015.