[Associations among non-metric features of the atlas in the human species].
Six non-metrical variants has been studied in a series of 500 human atlases. A bipartition of the superior articular facet has been observed in 20.8% of cases, a posterior ponticulus in 14.2% of cases, a retrotransverse ponticulus in 14.2% of cases, an anterior dehiscence of the foramen tranversarium in 10.2% of cases, a dehiscence of the posterior arch in 2.8% of cases, and a lateral ponticulus in 1.8% of cases. Bilateral occurrence has been noted in 42.2 to 46.2% of cases for the anterior dehiscence of the foramen transversarium, the posterior ponticulus, and the bipartition of the superior articular facet. Bilateral occurrence is less frequent for the retrotransverse ponticulus (29.6%), and particularly for the lateral ponticulus (11.1%). The incidence of a given lateral character according to the side has been found identical or similar on the left and on the right sides. In the present series, 51.6% of the atlases showed none of the six variants studied; 46.8% of the atlases showed one or two variants; and only 1.6% of the atlases showed more than two variants; any cases with more than four variants were observed. The most interesting association observed is the association of the lateral ponticulus with the posterior ponticulus.
Institut d'Anatomie Normale de la Faculté de Médecine de Strasbourg.
J M
JM
Le Minor
J G
JG
Koritke
D001270:Cervical Atlas / Q000033:anatomy & histology*; D006801:Humans
Associations entre caractères non-métriques de l'atlas dans l'espèce humaine.