The false and the true bifid condyles.

The bifid mandibular condyle has been described as a condition of unknown aetiology and uncertain pathogenesis. Many see it as the product of accidental trauma or forceps delivery, with the two heads occurring one behind the other in the sagittal plane. In bioanthropological literature, "bifid condyle" often describes pitting in the sagittal plane, dividing the condyle mediolaterally. We examined 38 male and 16 female pre-European-contact Pacific islanders' adult mandibles, and 24 male and 29 female modern Indian mandibles, recording frequency, prominence and position of any condylar groove in both coronal and sagittal planes. We report the tenth known case of a bilaterally-bifid condyle. A groove was found almost twice as likely to occur on the left condyle of the Indians than of the Pacific Islanders, but equally likely to occur on the right side of both groups. That same finding applied to males and females. In order to avoid terminological ambiguity, we suggest that the term "bifid condyle" should be reserved for describing multiple condyles in the sagittal plane only - the true bifid condyle. An hypothesis is offered for the occurrence of the groove in the sagittal plane.