The stress at the human atlanto-occipital joint

Abstract

The development of the occipital condyle has been observed in human fetuses, neonates, children, and juveniles. In contrast to some authorities, the authors believe the occipital condyle to originate from the basioccipital and the exoccipital of the occipital bone. The bony parts of the condyle are divided by the synchondrosis intraoccipitalis anterior. The rostral area on the basioccipital occupies about one-fourth to one-seventh of the surface of the subchondral bone. The sequence and mode of ossification of the synchondrosis intraoccipitalis anterior has been investigated. A causality between the synchondrosis and the occasionally observed subdivisions of the articular surface in the adult does not exist.

Duplication of the occipital condyles

“…True duplication of the occipital condyles has rarely been reported. We found only three reports in the literature describing this rarity (Harrower, 1923;Gladstone andWakeley, 1924 -1925;Tillmann and Lorenz, 1978). In our specimen, each occipital condyle for the left side measured 1.9 ϫ 1.3 cm (anterior condyle) and 1.6 ϫ 1.1 cm (posterior condyle).…”

Brief communication: Sexual dimorphism of the juvenile basicranium

“…We examined juveniles from 8 through to 19 years of age. Eight years of age is used as the lower limit in this study, as this is the age at which fusion of the anterior intraoccipital synchondroses are complete (Tillmann and Lorenz, 1978), thus halting further growth of the foramen magnum (Sheuer and Black, 2000). Eruption of the third molars was treated as a biological marker separating juveniles from adults.…”

“…The squamous portion of the occipital bone is primarily intramembranous in origin, with the exception of the nuchal region, which, like the two lateral exoccipitales and the basiocciput, ossifies endochondrally (Scheuer and Black, 2000). A number of studies (Zuckerman, 1955;Redfield, 1970;Tillmann and Lorenz, 1978;Sgouros et al, 1999;Scheuer and Black, 2000) have confirmed that most of the growth-related changes in the occipital bone and posterior cranial fossa occur during the first 5 years of life, before fusion of the intraoccipital synchondroses. Fusion of the anterior intraoccipital synchondroses can start as early as 3-4 years of age and are fused by 8 years of age (Tillmann and Lorenz, 1978), whereas the posterior synchondroses are fused by 5 years of age (Redfield, 1970).…”

“…A number of studies (Zuckerman, 1955;Redfield, 1970;Tillmann and Lorenz, 1978;Sgouros et al, 1999;Scheuer and Black, 2000) have confirmed that most of the growth-related changes in the occipital bone and posterior cranial fossa occur during the first 5 years of life, before fusion of the intraoccipital synchondroses. Fusion of the anterior intraoccipital synchondroses can start as early as 3-4 years of age and are fused by 8 years of age (Tillmann and Lorenz, 1978), whereas the posterior synchondroses are fused by 5 years of age (Redfield, 1970). Although, growth at the synchondroses stops prior to synostosis (Hoyte, 1997) increases in size of the basioccipital can still occur through displacement and drift (Hoyte, 1997;Lieberman et al, 2000;Scheuer and Black, 2000).…”

Evaluation of Sexual Dimorphism in North India Population Using Morphometric Analysis of Foramen Magnum

“…These elements are connected by symmetrical posterior and anterior intra-occipital synchondroses. Fusion of the posterior synchondroses takes place at 2-4 years of age, while the anterior synchondroses start to fuse at the same age but continues until the age of 5-7 [14]. The basilar part is also connected anteriorly with the body of the sphenoid bone by the spheno-occipital (sphenobasilar) synchondrosis, which disappears between the ages of 16-22 for males and 11-19 for females [15].…”