Vertebral malformations induced by sodium salicylate correlate with shifts in expression domains of Hox genes

Relationship of segmental variations in the human lumbar plexus to the length of the 12th rib

BACKGROUND

Evaluating segmental variations in the lumbar plexus is crucial for neurological diagnosis. In the present study, we examined the relationship between the segmental composition of the lumbar plexus and length of the 12th rib.

PROCEDURES

To evaluate segmental variations in the lumbar plexus, the furcal nerve (Nf) which forms the boundary between the lumbar and sacral plexus, was used as an index of plexus arrangement.

MAIN FINDINGS

Segmental variations in the Nf were classified into four groups on the basis of whether the Nf originated from the ventral rami of L3 and L4 (Nf L3 + L4 group), L4 (Nf L4 group), L4 and L5 (Nf L4 + L5 group), or L5 (Nf L5 group). The Nf L3 + L4 group was associated with short 12th rib, and groups Nf L4 + L5 and Nf L5 were associated with long 12th rib. These findings suggest that the segmental variations in the lumbar plexus are related to the length of the 12th rib.

CONCLUSIONS

Therefore, the segmental variations in the lumbar plexus can be evaluated non-invasively and easily by measuring the length of the 12th rib. This may contribute to the diagnosis and treatment of various lumbar radiculopathies.

Bone development in laboratory mammals used in developmental toxicity studies

Evaluation of the skeleton in laboratory animals is a standard component of developmental toxicology testing. Standard methods of performing the evaluation have been established, and modification of the evaluation using imaging technologies is under development. The embryology of the rodent, rabbit, and primate skeleton has been characterized in detail and summarized herein. The rich literature on variations and malformations in skeletal development that can occur in the offspring of normal animals and animals exposed to test articles in toxicology studies is reviewed. These perturbations of skeletal development include ossification delays, alterations in number, shape, and size of ossification centers, and alterations in numbers of ribs and vertebrae. Because the skeleton is undergoing developmental changes at the time fetuses are evaluated in most study designs, transient delays in development can produce apparent findings of abnormal skeletal structure. The determination of whether a finding represents a permanent change in embryo development with adverse consequences for the organism is important in study interpretation. Knowledge of embryological processes and schedules can assist in interpretation of skeletal findings.

Supernumerary lumbar ribs: a rare occurrence on an adult African male skeleton

Supernumerary lumbar ribs are usually asymptomatic and discovered incidentally during routine diagnostic radiography. During a routine inventory of the research skeletal repository at the University of the Witwatersrand, a rare case of bilateral supernumerary ribs on the first lumbar vertebra was observed. The skeletal specimen belonged to a 70-year-old African male whose recorded cause of death was esophageal carcinoma. Plain radiography revealed bilateral joint cavities between the transverse processes of the first lumbar vertebra and the supernumerary ribs. Clinically, supernumerary lumbar ribs may present with pain of the renal angle, cause confusion during enumeration of the vertebral levels on radiographs, and may be misinterpreted as fractures, kissing osteophytes, and/or calcification of abdominal vasculature.

Lumbar ribs: a comprehensive review

BACKGROUND

To date, no single comprehensive review has been published regarding lumbar ribs. Therefore, the present review was conducted to better elucidate these variant anatomical structures, which can be confused with transverse process fractures or result in miscounting of spine segments for surgical procedures.

METHODS

Using standard search engines, a review of lumbar ribs was performed.

CONCLUSIONS

Lumbar ribs are uncommon but can be misinterpreted on imaging or cause confusion during surgery. Mutations of the FGD1 or Hox10 gene may be involved in the development of lumbar ribs. Knowledge of these structures can decrease misdiagnosis when they are present.

Analysis of cervical ribs in a series of human fetuses

In humans, an increasing body of evidence has linked the frequency of cervical ribs to stillbirths, other malformations and early childhood cancers. However, the frequency of cervical ribs in a putatively healthy fetal population is not sufficiently known to assess the actual medical risks of these prenatal findings. We therefore analyzed the presence of skeletal anomalies in a series of 199 electively aborted fetuses, which were whole-mount stained with alizarin red specific for skeletal tissues. Results show that approximately 40% of the fetuses had cervical ribs, even though external congenital abnormalities such as craniofacial and limb defects were absent. A literature overview indicates that the observed frequency of cervical ribs is comparable to results previously obtained for deceased fetuses with no or minor congenital anomalies, and higher than expected for healthy fetuses. This unexpected result can probably in part be explained by a higher detection rate of small cervical ribs when using alizarin red staining instead of radiographs. Additionally, studies in the literature suggest that the size of a cervical rib may indicate the severity of abnormalities, but this possibility requires further research. Anomalies of the axial skeleton are known to be caused by a disturbance of early development, which alters Hox gene expression, but in this study the origin of the stress could not be verified as maternal medical data were not available. The co-occurrence of rudimentary or absent 12th ribs in 23.6% of the cases with cervical ribs indicates that in approximately 8% of the fetuses a homeotic shift occurred over a larger part of the vertebral column. This suggests that the expression of multiple Hox genes may have been affected in these fetuses. Together, the high incidence of cervical ribs and also their co-occurrence with rudimentary or absent 12th ribs suggests that there may have been a disturbance of early development such that the studied fetuses are probably not informative about the general population. Future studies determining the frequency of cervical ribs in a more healthy fetal population are therefore needed to evaluate their potential as an indicator of medical risks.