Ventral Arc
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Description: The ventral arc is “a slightly elevated ridge of bone which extends from the pubic crest and arcs inferiorly across the ventral surface of the lateral most extension of the subpubic concavity where it blends with the medial border of the ischio-pubic ramus’’ (Phenice, 1969: 298). The ventral arc serves as an attachment site for various muscles including the gracilis, adductor brevis, and adductor magnus. While a true ventral arc is only present in females, a ridge of bone along the ventral aspect of the pubis can also be found in males: however, the angle and orientation of this bony ridge is different in males and females, allowing distinctions between the sexes to be made. Klales et al.’s (2012) modified Phenice description includes the angle and orientation of the bony ridge in relation to the symphyseal face, and also takes into consideration the overall morphology of the region inferior and medial to the arc (red arrows indicates extra triangle of bone). The overall shape of this region should be considered (e.g., squared in scores 1-2 vs. sloping on inferior edge in scores 3-5) secondary to the presence and angle of the arc (blue lines).
Scoring: The ventral surface of the pubis bone should be perpendicular to the viewer and the superior pubic ramus should be aligned horizontal or straight. In proper orientation, the symphyseal face should not be visible, only the ventral edge or rim. |
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