Variability and constraint in the mammalian vertebral column

Variability and constraint in the mammalian vertebral column.

Patterns of vertebral variation across mammals have seldom been quantified, making it difficult to test hypotheses of covariation within the axial skeleton and mechanisms behind the high level of vertebral conservatism among mammals. We examined variation in vertebral counts within 42 species of mammals, representing monotremes, marsupials and major clades of placentals. These data show that xe...

Vertebral and rib anatomy in Caperea marginata: Implications for evolutionary patterning of the mammalian vertebral column

The pygmy right whale, Caperea marginata, is a rare mysticete cetacean with an unusual suite of axial skeletal characters. Distally expanded first ribs, a long thorax with broadly overlapping vertebral transverse processes, plate-like posterior ribs, and a short tail contrast with other cetaceans and suggest unique developmental patterning. Twenty-four individuals of diverse ontogenetic age wer...

The ossification of the vertebral column, thorax and sternum in the quail (Coturnix coturnix japonica)

The ossification centers onset of the quail vertebrae, ribs, and sternum in embryos and hatchling birds was studied. Specimens were cleared, stained with Alcian Blue and Alizarin Red S and examined using stereomicroscope. The chondral rudiments of the vertebrae were observed at the 6th day of incubation (E6). The osteogenesis of the vertebrae was accomplished with both perichondral a...

Tumors of the vertebral column.

The clinical is, in most instances, non-specific. Pain is a common symptom, and may be spontaneous or be of a mechanical nature. It may simulate all the clinical syndromes of the degenarative spinal disorders, and thus it is not surprising that the correct diagnosis is often quite delayed. An expanding mass, which may reach considerable size is another manifestation. Finally as the tumor encroa...

Spondylolysis in the Koniag Eskimo Vertebral Column