Three-dimensional ultrasound diagnosis of Larsen syndrome with further characterization of neurological sequelae.

Larsen syndrome consists of skeletal dysplasia with multiple joint dislocations and a characteristic facies. The basis of this abnormality is a generalized mesenchymal disorder involving connective tissues. We describe our findings in a woman who was referred at 28 weeks' gestation due to multiple fetal anomalies suspected initially at an 18-week ultrasound examination. On three-dimensional (3D) ultrasound we found the fetus had bilateral genu recurvatum. Further 3D examination at 36 weeks confirmed the lower limb anomaly and revealed facial anomalies that led to the diagnosis of Larsen syndrome. An elective Cesarean section was performed at 38 weeks' gestation to minimize neurological sequelae. Magnetic resonance imaging was performed postnatally and showed pachygyria, colpocephaly and agenesis of the corpus callosum. In this case, 3D ultrasound facilitated the prenatal diagnosis of Larsen syndrome. A careful prenatal investigation for other associated anomalies such as those of the cardiovascular or neurological systems is warranted with this diagnosis. These associated lesions are likely to have a greater impact on prognosis than the classic symptoms of Larsen syndrome and a collaborative approach is necessary to optimize delivery and postnatal management of an affected fetus.

Congenital dislocation of the patella. Part I: pathologic anatomy.

There has been considerable confusion between true congenital dislocation of the patella and other patellar instabilities. Only very few papers describing the anatomical features of congenital dislocation of the patella are found in the literature. The purpose of this paper was to describe the anatomical anomalies found in two cadaver specimens of a true permanent and irreducible congenital patellar dislocation. The quadriceps femoris is short and displaced laterally and acts as a knee flexor. The patella is small, articulating with the outer aspect of the lateral condyle, with no possibility of medial reduction onto the trochlea. Many other anomalies involving the bones, muscles, and nervous structures were found. Congenital dislocation of the patella must be distinguished from other patellar dislocations in children. The severity of structural anomalies is mainly owing to its prenatal onset. Congenital

The embryogenesis of congenital vertebral dislocation: early embryonic buckling?

Congenital vertebral dislocation (CVD) is a rare congenital spinal malformation characterized by a translatory or rotatory vertebral displacement, or both, at a single level, that results in an abrupt angulation of the neural canal. The more caudal vertebra is dysplastic and appears at first glance to be posteriorly dislocated into the vertebral canal as a posterior hemivertebra, but is actually well aligned with the more caudal vertebral column. Unfortunately, the present classification of complex congenital vertebral anomalies is confusing, and CVD has been grouped together with other congenital vertebral malformations under the terms 'segmental spinal dysgenesis', 'medial spinal aplasia', and others. Moreover, a putative embryonic mechanism has never been proposed for CVD. Based upon our experience with 6 children and a critical review of the literature, we identify CVD as a distinct entity having characteristic anatomical features. We propose a novel putative embryonic mechanism - early embryonic 'buckling' - which likely occurs by the 6th embryonic week, prior to the period of axonal outgrowth and the beginning of vertebral chondrification.

Craniovertebral junction anomalies in inherited disorders: part of the syndrome or caused by the disorder?

Patterns of skeletal abnormality at the craniovertebral junction in the normal population and in syndromes such as Down, Morquio etc, are compared and the recent embryological data and comparative anatomy reviewed. The authors' view based on their own clinical and radiological experience is that the os odontoideum is the product of excessive movement at the time of ossification of the cartilaginous dens and is exactly analogous to the unfused Type II odontoid fracture. True hypoplasia of the odontoid peg is part of a wider segmentation defect associated with Klippel Feil, occipitalised atlas and/or basilar invagination; it is hardly ever associated with instability.

Early intrauterine presence of congenital dislocation of the knee.

We report the histologic findings of congenital dislocation of both knees of a 19.5-week-old spontaneously aborted fetus. Grossly and histologically, both knees were grade II congenital dislocations (subluxation), which are characterized by hyperextension of the knee with rotatory subluxation. Comparing the morphologic changes to age-matched normal controls allowed us to distinguish between primary and secondary changes. The most impressive fetal abnormalities were partial fibrosis of the quadriceps, absence of a suprapatellar pouch and incomplete patellofemoral joint cavitation. The presence of these findings suggests that they most likely cause, and do not result from, dislocation. This specimen is the first preterm fetus to be described with the features of congenital dislocation of the knee of any type.