We report avian cervical vertebrae from the Quercy fissure fillings in France, which are densely covered with villi-like tubercles. Two of these vertebrae stem from a late Eocene site, another lacks exact stratigraphic data. Similar cervical vertebrae occur in avian species from Eocene fossils sites in Germany and the United Kingdom, but the new fossils are the only three-dimensionally preserved vertebrae with pronounced surface sculpturing. So far, the evolutionary significance of this highly bizarre morphology, which is unknown from extant birds, remained elusive, and even a pathological origin was considered. We note the occurrence of similar structures on the skull of the extant African rodent Lophiomys and detail that the tubercles represent true osteological features and characterize a distinctive clade of Eocene birds (Perplexicervicidae). Micro-computed tomography (μCT) shows the tubercles to be associated with osteosclerosis of the cervical vertebrae, which have a very thick cortex and much fewer trabecles and pneumatic spaces than the cervicals of most extant birds aside from some specialized divers. This unusual morphology is likely to have served for strengthening the vertebral spine in the neck region, and we hypothesize that it represents an anti-predator adaptation against the craniocervical killing bite ("neck bite") that evolved in some groups of mammalian predators. Tuberculate vertebrae are only known from the Eocene of Central Europe, which featured a low predation pressure on birds during that geological epoch, as is evidenced by high numbers of flightless avian species. Strengthening of the cranialmost neck vertebrae would have mitigated attacks by smaller predators with weak bite forces, and we interpret these vertebral specializations as the first evidence of "internal bony armor" in birds.

• Klíčová slova
• Aves, adaptation, evolution, fossil birds, morphology,
• MeSH
• biologická evoluce * MeSH
• fylogeneze MeSH
• krční obratle anatomie a histologie   MeSH
• ptáci * anatomie a histologie   MeSH
• rentgenová mikrotomografie MeSH
• savci MeSH
• zkameněliny MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

PURPOSE: The most common injuries to the upper cervical spine are fractures of the dens axis. Therefore, the purpose of our study was to answer three questions, namely (1) whether the size of the dens is adequate at all levels to accommodate two screws, (2) what the angle of the posterior tilt of the dens is in a healthy individual and (3) compare the measured variables between the sexes. METHODS: The cohort comprised 50 males and 50 females CT examination of the craniocervical junction. We measured the five diameters of the dens and posterior dens angulation angle (PDAA) and screw insertion angle (SIA). The same dimensions were measured in a control group, consisting of 40 non-pathological second cervical vertebrae specimens. RESULTS: On CT scans, the mean PDAA was 162.7 degrees in males and 160.26 degrees in females; the mean SIA was 62.0 degrees in males and 60.2 degrees in females. On specimens, the mean PDAA was 169.47 degrees in males and 166.95 degrees in females; the mean SIA was 65.42 degrees in males and 64.47 degrees in females. All obtained values were higher in males; regardless of their measuring on either CT scans or specimens, differences between males and females were statistically significant (p < 0.05) in a, c, d and e values. CONCLUSIONS: The values of our measurements correlate with the dimensions identified previously in other studies. Based on our clinical experience and measurements, we presume that two 3.5-mm screws can be inserted into the dens of all adult patients, except for those with pronounced anatomical anomalies. Posterior dens angulation angle is slightly larger than we expected. The dens is significantly larger in males almost in all measurement. These slides can be retrieved under Electronic Supplementary Material.

• Klíčová slova
• C2 anatomy, C2 fracture, Dens fracture, Posterior dens angulation angle, Screw insertion angle,
• MeSH
• dens axis * anatomie a histologie   chirurgie   MeSH
• fraktury páteře * patologie   chirurgie   MeSH
• kohortové studie MeSH
• kostní šrouby MeSH
• krční obratle * anatomie a histologie   chirurgie   MeSH
• lidé MeSH
• počítačová rentgenová tomografie MeSH
• vnitřní fixace fraktury MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The aim of this retrospective study of 330 rabbits (164 males, 166 females) was to determine different vertebral formulas and prevalence of congenital vertebral anomalies in rabbits from radiographs of the cervical (C), thoracic (Th), lumbar (L) and sacral (S) segments of the vertebral column. The number of vertebrae in each segment of vertebral column, position of anticlinal vertebra and localisation and type of congenital abnormalities were recorded. In 280/330 rabbits (84.8%) with normal vertebral morphology, seven vertebral formulas were identified: C7/Th12/L7/S4 (252/330, 76.4%), C7/Th12/L6/S4 (11/330, 3.3%), C7/Th13/L7/S4 (8/330, 2.4%), C7/Th12/L7/S5 (4/330, 1.2%), C7/Th12/L8/S4 (3/330, 0.9%), C7/Th12/L7/S6 (1/330, 0.3%) and C7/Th11/L7/S4 (1/330, 0.3%). The anticlinal vertebra was identified as Th10 in 56.4% of rabbits and Th11 in 42.4% of rabbits. Congenital spinal abnormalities were identified in 50/330 (15.2%) rabbits, predominantly as a single pathology (n=44). Transitional vertebrae represented the most common abnormalities (n=41 rabbits) in the thoracolumbar (n=35) and lumbosacral segments (n=6). Five variants of thoracolumbar transitional vertebrae were identified. Cervical butterfly vertebrae were detected in three rabbits. One rabbit exhibited three congenital vertebral anomalies: cervical block vertebra, thoracic hemivertebra and thoracolumbar transitional vertebra. Five rabbits exhibited congenital vertebral abnormalities with concurrent malalignment, specifically cervical kyphosis/short vertebra (n=1), thoracic lordoscoliosis/thoracolumbar transitional vertebrae (n=1), thoracic kyphoscoliosis/wedge vertebrae (n=2) and thoracolumbar lordoscoliosis/thoracolumbar transitional vertebrae/lumbosacral transitional vertebrae (n=1). These findings suggest that vertebral columns in rabbits display a wide range of morphologies, with occasional congenital malformations.

• Klíčová slova
• Congenital anomaly, Rabbit, Radiography, Spine, Transitional vertebra,
• MeSH
• bederní obratle abnormality   anatomie a histologie   MeSH
• hrudní obratle abnormality   anatomie a histologie   MeSH
• králíci * abnormality   anatomie a histologie   MeSH
• krční obratle abnormality   anatomie a histologie   MeSH
• křížová kost MeSH
• kyfóza diagnostické zobrazování   veterinární   MeSH
• radiografie metody   veterinární   MeSH
• retrospektivní studie MeSH
• skolióza diagnostické zobrazování   veterinární   MeSH
• zvířata MeSH
• Check Tag
• králíci * abnormality   anatomie a histologie   MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

PURPOSE: To present a method of posterior arch and lateral mass screw (PALMS) insertion and to prove its feasibility. METHODS: Four formalin-fixed specimens and 40 macerated atlas vertebras were used to describe the relevant anatomy. The height of the posterior arch was measured on 42 consecutive patients using standard CT of the cervical spine. The operative technique and the special CT reconstructions used for preoperative planning are described. Eight patients underwent posterior fixation using this technique. RESULTS: We described the relevant anatomy and important anatomical landmarks of the posterior arch of the atlas. PALMS placement was modified according to these anatomical findings. Fifteen PALMSs were placed in eight patients using this technique without vascular or neural injury. CONCLUSION: It is feasible to place PALMS using the described technique. CT angiography is of crucial importance for preoperative planning using the described special reconstructions. The arch posterior to the lateral mass (APLM) is defined as the bone stock situated posterior to the lateral mass, respecting its convergence. The ideal entry point for a PALMS is on the APLM above the center of the converging lateral mass. A complete or incomplete ponticulus posticus and a retrotransverse foramen or groove can be used as an accessory landmark to refine the entry point.

• Klíčová slova
• Atlantoaxial fixation, Atlas, Atlas anatomy, Atlas pedicle screw, Posterior arch screw,
• MeSH
• arteria vertebralis diagnostické zobrazování   MeSH
• arteriae carotides diagnostické zobrazování   MeSH
• atlas (obratel) anatomie a histologie   chirurgie   MeSH
• CT angiografie MeSH
• dospělí MeSH
• fraktury páteře patologie   chirurgie   MeSH
• fúze páteře přístrojové vybavení   metody   MeSH
• implantace protézy metody   MeSH
• kostní šrouby * MeSH
• krční obratle anatomie a histologie   zranění   chirurgie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mrtvola MeSH
• počítačová rentgenová tomografie MeSH
• protézy - design MeSH
• studie proveditelnosti MeSH
• výsledek terapie MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH

Vertebral column pathologies requiring surgical intervention have been described in pet ferrets, however little information is available on the normal vertebral formula and congenital variants in this species. The purpose of this retrospective study was to describe vertebral formulas and prevalence of congenital vertebral anomalies in a sample of pet ferrets. Radiographs of 172 pet ferrets (96 males and 76 females) were included in this retrospective study. In 143 ferrets (83.14%), five different formulas of the vertebral column were recorded with normal morphology of vertebrae (rib attachment included) but with a variable number of thoracic (Th), lumbar (L), and sacral (S) vertebrae. The number of cervical (C) vertebrae was constant in all examined animals. Observed vertebral formulas were C7/Th14/L6/S3 (51.74%), C7/Th14/L6/S4 (22.10%), C7/Th14/L7/S3 (6.98%), C7/Th15/L6/S3 (1.74%), and C7/Th15/L6/S4 (0.58%). Formula C7/Th14/L6/S4 was significantly more common in males than in females (P < 0.05). Congenital spinal abnormalities were found in 29 ferrets (16.86%), mostly localized in the thoracolumbar and lumbosacral regions. The cervical region was affected in only one case. Transitional vertebrae represented the most common congenital abnormalities (26 ferrets) in the thoracolumbar (13 ferrets) and lumbosacral regions (10 ferrets) or simultaneously in both regions (three ferrets). Other vertebral anomalies included block (two ferrets) and wedge vertebra (one ferret). Spina bifida was not detected. Findings from the current study indicated that vertebral formulas may vary in ferrets and congenital abnormalities are common. This should be taken into consideration for surgical planning.

• Klíčová slova
• Mustelidae, congenital anomaly, radiograph, spine, transitional vertebra,
• MeSH
• bederní obratle abnormality   anatomie a histologie   MeSH
• fretky abnormality   anatomie a histologie   MeSH
• hrudní obratle abnormality   anatomie a histologie   MeSH
• krční obratle abnormality   anatomie a histologie   MeSH
• křížová kost abnormality   anatomie a histologie   MeSH
• páteř abnormality   anatomie a histologie   MeSH
• retrospektivní studie MeSH
• sexuální faktory MeSH
• žebra abnormality   anatomie a histologie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

• MeSH
• bederní obratle anatomie a histologie   MeSH
• fylogeneze MeSH
• hrudní obratle anatomie a histologie   MeSH
• krční obratle anatomie a histologie   MeSH
• lidé MeSH
• ocas MeSH
• páteř anatomie a histologie   MeSH
• savci MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH

• MeSH
• dospělí MeSH
• kloubní chrupavka anatomie a histologie   MeSH
• klouby anatomie a histologie   MeSH
• krční obratle anatomie a histologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• senioři MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

• MeSH
• krční obratle anatomie a histologie   fyziologie   MeSH
• lidé MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

• MeSH
• fyzika MeSH
• fyzikální jevy MeSH
• krční obratle anatomie a histologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• ligamenta anatomie a histologie   MeSH
• poranění míchy * MeSH
• poranění páteře * MeSH
• pružnost * MeSH
• senioři MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• senioři MeSH
• Publikační typ
• časopisecké články MeSH