Objectives This study investigates the effect of scanning parameters on the accuracy of measurements from three-dimensional multi-detector computed tomography (3D-CT) mandible renderings. A broader range of acceptable parameters can increase the availability of CT studies for retrospective analysis. Study Design Three human mandibles and a phantom object were scanned using 18 combinations of slice thickness, field of view, and reconstruction algorithm and three different threshold-based segmentations. Measurements of 3D-CT models and specimens were compared. Results Linear and angular measurements were accurate, irrespective of scanner parameters or rendering technique. Volume measurements were accurate with a slice thickness of 1.25 mm, but not 2.5 mm. Surface area measurements were consistently inflated. Conclusions Linear, angular and volumetric measurements of mandible 3D-CT models can be confidently obtained from a range of parameters and rendering techniques. Slice thickness is the primary factor affecting volume measurements. These findings should also apply to 3D rendering using cone-beam-CT.

We reviewed etiologic and phenotypic aspects of those orofacial and limb anomalies usually diagnosed as Hanhart syndrome and Mobius syndrome but also those described, among others, under names such as aglossia-adactylia syndrome, gloss-palatine ankylosis, ankyloglossia superior, peromelia and micrognathia, cleft palate/lateral synechiae syndrome, and the Charlie M. syndrome. By coding the degree of severity of the limb defects it was possible to compare these cases quantitatively and to determine the nosologic significance of associated cranial nerve palsies and chest abnormalities. We analyzed 7 personal and 62 previously reported cases and found: 1. that the severity in the upper limbs and, particularly, malformations of the feet, but not the presence or absence of cranial nerve palsies, is a significant feature in the differentiation of cases, and 2. that the group of patients with cranial nerve palsies includes some with limb defects similar to those in the Hanhart syndrome and others with features which overlap the manifestations of the Poland syndrome. Still other cases had cranial nerve palsy as an isolated trait or as a component manifestation of several different syndromes. These findings permit re-definition and nosologic delimitation of the various syndromes as follows: 1. The Hanhart-syndrome: usually severe limb defect of at least one hand or foot, frequently associated with severe oral abnormalities and sometimes also with cranial nerve palsy. Most cases reported as aglossia-adactylia syndrome, aglossia-hypomelia syndrome, and some cases reported as glossopalatine ankylosis, ankyloglossia superior and Mobius syndrome describe instances of the Hanhart syndrome. 2. The Poland-Mobius syndrome: we suggest this term to refer to those cases of "Mobius syndrome" which have a chest defect and/or symbrachydactyly of the type seen in the Poland syndrome. We suspect that these cases of the "Mobius syndrome," and most of the cases which are usually diagnosed as Poland syndrome represent a different spectrum of the same condition, hence the term Poland-Mobius syndrome. 3. The autosomal dominant cleft palate/lateral synechiae syndrome delineated by Fuhrmann et al. and other apparently less frequent conditions are mentioned in the discussion. Cranial nerve palsy obviously occurs in several etiologically distinct conditions. An analogous situation is present, although less obvious, in the Hanhart and the Poland-Mobius syndrome. Both of these conditions are formal genesis malformation syndromes which implies that they are etiologically non-specific developmental field complexes. In the Hanhart syndrome Bersu et al. postulate a common pathogenetic disturbance for oral and limb defects, thus suggesting that the manifestations represent a single anomaly rather than a "syndrome." This anomaly, for which we suggest the term Kettner anomaly, may occur not only in the Hanhart syndrome but also in other conditions. Similarly, the Poland anomaly, i.e...

The hyoid bone supports the important functions of swallowing and speech. At birth, the hyoid bone consists of a central body and pairs of right and left lesser and greater cornua. Fusion of the greater cornua with the body normally occurs in adulthood, but may not occur at all in some individuals. The aim of this study was to quantify hyoid bone fusion across the lifespan, as well as assess developmental changes in hyoid bone density. Using a computed tomography imaging studies database, 136 hyoid bones (66 male, 70 female, ages 1-to-94) were examined. Fusion was ranked on each side and hyoid bones were classified into one of four fusion categories based on their bilateral ranks: bilateral distant non-fusion, bilateral non-fusion, partial or unilateral fusion, and bilateral fusion. Three-dimensional hyoid bone models were created and used to calculate bone density in Hounsfield units. Results showed a wide range of variability in the timing and degree of hyoid bone fusion, with a trend for bilateral non-fusion to decrease after age 20. Hyoid bone density was significantly lower in adult female scans than adult male scans and decreased with age in adulthood. In sex and age estimation models, bone density was a significant predictor of sex. Both fusion category and bone density were significant predictors of age group for adult females. This study provides a developmental baseline for understanding hyoid bone fusion and bone density in typically developing individuals. Findings have implications for the disciplines of forensics, anatomy, speech pathology, and anthropology.

We report the anatomical variations of the limbs in eight infants with the trisomy-18 syndrome that were dissected and studied in detail. In each case, the upper limbs showed defects which further define the specific influence of this aneuploidy on the development of its preaxial (radial) component, and the tendency towards reduction defects. Abnormalities included muscle variations concentrated along the radial margin of the forearm and hand, the absence of the definitive musculocutaneous nerve in all of the limbs, and reductions of the radial artery in four of the bodies. Pathogenetic mechanisms explaining the observed defects are discussed, and include: 1) a defect in peripheral nerve development; or 2) tissue necrosis. The characteristic flexion deformities of the fingers seem to be due to a displacement of the tendons of extensors digitorum and digiti minimi. The lower limbs did not show a consistent pattern of defects, except for the absence of some muscles (psoas minor, the tendon of flexor digitorum brevis to digit V), and the presence of several supernumerary muscles. These variations are discussed as possible nonspecific effects of 18-trisomy on development. The additional anatomical data from this and the first paper in this series [Bersu and Ramirez-Castro, 1977] provide a more detailed picture of the trisomy-18 phenotype which may be useful in corroborating an unconfirmed clinical diagnosis of the syndrome.

No abstract