Revision of the aïstopod genus Phlegethontia (Tetrapoda: Lepospondyli)

2002 ◽  
Vol 76 (6) ◽  
pp. 1029-1046 ◽  
Author(s):  
Jason S. Anderson
Keyword(s):  
Jugular Foramen ◽  
Foramen Magnum ◽  
Pectoral Girdle ◽  
Parietal Foramen ◽  
The Family ◽  
Mazon Creek ◽  
Related Feature ◽  
Cranial Kinesis ◽  
Potential Mobility ◽  
Sagittal Crest

The aïstopod family Phlegethontiidae is restudied based on new specimens from Pit 11 of Mazon Creek, Illinois, and the coal shales of Nýřany, Czech Republic, as well as most available specimens from North America. Phlegethontiids have highly fenestrate skulls, with orbits placed just anterior their skull's mid point. Dermal skull bones are greatly reduced in number and limited in extent, whereas the endochondral braincase is hyperossified. The frontals are fused medially and enclose the parietal foramen and anterior sagittal crest. As in most other aïstopods, the quadrate, pterygoid, and epipterygoid are fused into a composite bone, the palatoquadrate complex. Details of cranial anatomy contradict a previous model of cranial kinesis by severely limiting the skull's potential mobility. Remnants of the pectoral girdle are present, perhaps due to the presence of an operculum–opercularis-like connection to the stapes. No remnants of the pelvis are present.Three species are recognised within the family. Phlegethontia linearis has short anterior vertebrae, high neural spines on at least the anterior four vertebrae, and vertebrae number between 230–250 in total. Phlegethontia longissima has low neural spines throughout the column, anterior vertebrae that are twice as long as P. linearis, and only 200–210 total vertebrae. Sillerpeton permianum, known from a single braincase and an unassociated string of vertebrae, is distinguished from Phlegethontia by the retention of a separate foramen for the passage of the occulomotor nerve. Phlegethontia “phanerhalpa” is a tiny braincase fragment that differs from the other species of Phlegethontia only in the placement of the jugular foramen relative to the centre of the foramen magnum. This is probably a size-related feature, and P. “phanerhalpa” is considered a nomen dubium.

Endoscopic third ventriculostomy in hydrocephalus associated with achondroplasia

2012 ◽  
Vol 9 (1) ◽  
pp. 73-81 ◽  
Author(s):  
Dale Swift ◽  
Laszlo Nagy ◽  
Brian Robertson
Keyword(s):  
Endoscopic Third Ventriculostomy ◽  
Obstructive Hydrocephalus ◽  
Venous Pressure ◽  
Jugular Foramen ◽  
Foramen Magnum ◽  
Variable Pressure ◽  
Dural Sinus ◽  
Third Ventriculostomy ◽  
Suboccipital Decompression ◽  
Ventricle Size

Hydrocephalus in patients with achondroplasia is thought to be due to increased dural sinus venous pressure resulting from narrowing of the jugular foramen. In this setting, where hydrocephalus is presumed to be “vascular” in origin and therefore communicating, endoscopic third ventriculostomy (ETV) would seem contraindicated. The authors describe 3 patients in whom ETV was successfully performed, resulting in MR imaging–documented decreases in ventricle size. The patients were 11 months, 33 months, and 13 years at the time of surgery. All patients had serial preoperative MR images demonstrating progressive hydrocephalus in a “triventricular” pattern with a small fourth ventricle but an open aqueduct. All patients had undergone suboccipital decompression for foramen magnum stenosis prior to the treatment of hydrocephalus. Preoperative retrograde venography revealed variable pressure gradients across the jugular foramen. It is postulated that the increase in intracranial venous pressure resulting from jugular foramen stenosis may lead to disproportionate venous engorgement of the cerebellum and some degree of obstructive hydrocephalus amenable to ETV. The authors discuss the role of suboccipital decompression in the progression of hydrocephalus in patients with achondroplasia.

New Homoiopteridae (Insecta: Paleodictyoptera) with wing articulation from Upper Carboniferous strata of Mazon Creek, Illinois

1983 ◽  
Vol 61 (7) ◽  
pp. 1670-1687 ◽  
Author(s):  
Jarmila Kukalová-Peck ◽  
Eugene S. Richardson Jr.
Keyword(s):  
Late Paleozoic ◽  
Upper Carboniferous ◽  
The Family ◽  
Mazon Creek

New adults, a subadult, and a nymph of primitive, giant, Late Paleozoic Paleodictyoptera (Homoiopteridae) are described from Upper Carboniferous (Westphalian C–D) strata of Illinois: Mazothairos enormis gen. et sp. nov., Mazonopterum wolfforum gen. et sp. nov., Adolarryia bairdi gen. et sp. nov., Larryia osterbergi gen. et sp. nov., and Turneropterum turneri gen. et sp. nov. Some of these fossils show dorsal wing articulation, the most primitive known in the Pterygota. The biology of Paleodictyopteroidea is discussed. The family Homoiopteridae is reviewed for plesiomorphic features in venation that have been either reduced or transformed in modern insects, including paired costa, subcosta, and anal, and doubled radial stems.

The Asterion-to-Transverse Process of the Atlas Line as a Surgical Landmark

2021 ◽  
Author(s):  
Jaafar Basma ◽  
Dom E. Mahoney ◽  
Christos Anagnostopoulos ◽  
L. Madison Michael ◽  
Jeffrey M. Sorenson ◽  
...  
Keyword(s):  
Skull Base ◽  
Cranial Nerves ◽  
Three Dimensional ◽  
Transverse Process ◽  
Jugular Foramen ◽  
Foramen Magnum ◽  
Sigmoid Sinus ◽  
Cervical Region ◽  
Surgical Approaches ◽  
Anatomical Location

Abstract Introduction Proposed landmarks to predict the anatomical location and trajectory of the sigmoid sinus have varying degrees of reliability. Even with neuronavigation technology, landmarks are crucial in planning and performing complex approaches to the posterolateral skull base. By combining two major dependable structures—the asterion (A) and transverse process of the atlas (TPC1)—we investigate the A-TPC1 line in relation to the sigmoid sinus and in partitioning surgical approaches to the region. Methods We dissected six cadaveric heads (12 sides) to expose the posterolateral skull base, including the mastoid and suboccipital bone, TPC1 and suboccipital triangle, distal jugular vein and internal carotid artery, and lower cranial nerves in the distal cervical region. We inspected the A-TPC1 line before and after drilling the mastoid and occipital bones and studied the relationship of the sigmoid sinus trajectory and major muscular elements related to the line. We retrospectively reviewed 31 head and neck computed tomography (CT) angiograms (62 total sides), excluding posterior fossa or cervical pathologies. Bone and vessels were reconstructed using three-dimensional segmentation software. We measured the distance between the A-TPC1 line and sigmoid sinus at different levels: posterior digastric point (DP), and maximal distances above and below the digastric notch. Results A-TPC1 length averaged 65 mm and was posterior to the sigmoid sinus in all cadaver specimens, coming closest at the level of the DP. Using the transverse-asterion line as a rostrocaudal division and skull base as a horizontal plane, we divided the major surgical approaches into four quadrants: distal cervical/extreme lateral and jugular foramen (anteroinferior), presigmoid/petrosal (anterosuperior), retrosigmoid/suboccipital (posterosuperior), and far lateral/foramen magnum regions (posteroinferior). Radiographically, the A-TPC1 line was also posterior to the sigmoid sinus in all sides and came closest to the sinus at the level of DP (mean, 7 mm posterior; range, 0–18.7 mm). The maximal distance above the DP had a mean of 10.1 mm (range, 3.6–19.5 mm) and below the DP 5.2 mm (range, 0–20.7 mm). Conclusion The A-TPC1 line is a helpful landmark reliably found posterior to the sigmoid sinus in cadaveric specimens and radiographic CT scans. It can corroborate the accuracy of neuronavigation, assist in minimizing the risk of sigmoid sinus injury, and is a useful tool in planning surgical approaches to the posterolateral skull base, both preoperatively and intraoperatively.

Vertebral Artery Surgery - An Overview of Techniques and Discussion Points for the Future

2011 ◽  
Vol 6 (3) ◽  
pp. 193
Author(s):  
Bernard George ◽  
Keyword(s):  
Vertebral Artery ◽  
Jugular Foramen ◽  
Craniocervical Junction ◽  
Foramen Magnum ◽  
Surgical Anatomy ◽  
Surgical Approaches ◽  
Arteriovenous Fistulas ◽  
Intermittent Compression ◽  
Safety And Reliability ◽  
And Control

The vertebral artery (VA) is an important vessel supplying the hind brain; its surgical exposure and control is usually considered a great challenge. In fact, with good knowledge of surgical anatomy and proper surgical technique, the VA can be controlled and occasionally repaired with safety and reliability. VA exposure is useful in many instances and helps attain better results in the surgical treatment of many different pathologies at any level all along its course in the neck and the skull. These pathologies include intrinsic lesions (atherosclerosis, aneurysms, arteriovenous fistulas), intermittent compression by osteophytes or fibrous bands, and permanent compression mostly by different types of tumours. VA exposure also helps to achieve better treatment of spondylotic myelopathy (by oblique corpectomy) and of tumours at the craniocervical junction, foramen magnum and jugular foramen level. Based on the experience of more than 1,600 surgical approaches, VA surgery is associated with a very limited morbidity and mortality.

Morphological and Dietary Correlates of Clutch Size in North American Woodpeckers

The Auk ◽  
1987 ◽  
Vol 104 (4) ◽  
pp. 757-765 ◽  
Author(s):  
Walter D. Koenig
Keyword(s):  
Life History ◽  
Body Size ◽  
Clutch Size ◽  
North American ◽  
Life History Evolution ◽  
Morphological Characters ◽  
The Family ◽  
Size And Morphology ◽  
Cranial Kinesis ◽  
Wood Boring

Abstract There are diverse relations among ecological, morphological, and life-history traits in North American woodpeckers (family Picidae). Within the family as a whole, clutch size does not correlate with body size. However, clutch size increases with body size within the genus Melanerpes and decreases with size in Picoides. In the family as a whole, species that specialize on wood-boring larvae have small clutches. Such species use pecking as a major foraging technique, and pecking is associated with a wide suite of morphological specializations, including relatively wide first ribs, long pygostyle disks, short tibia, wide crania, wide maxillae, long mandibular symphyses, less cranial kinesis, and greater culmen sexual dimorphism. Hence, these morphological characters also correlate with clutch size, in two cases (length of the mandibular symphysis and cranial kinesis) even after controlling for both body size and generic effects. The observed correlations between clutch size and morphology are probably the result of dietary influences. These correlations, however, may at least in part be due to morphological constraints. Morphological design may thus constrain life-history evolution at the intrafamilial and intrageneric levels as well as at higher taxonomic levels.

scholarly journals Review of the Extinct Family Syntonopteridae (Order Uncertain)

1987 ◽  
Vol 94 (3-4) ◽  
pp. 373-388 ◽  
Author(s):  
Frank M. Carpenter
Keyword(s):  
New Genus ◽  
The Other ◽  
New Genus And Species ◽  
Upper Carboniferous ◽  
The Family ◽  
Mazon Creek

The family Syntonopteridae was named by Handlirsch in 1911 for a new genus and species, Syntonoptera schucherti, from the Upper Carboniferous of Mazon Creek, Illinois. Although the unique specimen on which the species was based consisted of only a wing fragment, the presence of several intercalary, triad veins was of unusual interest. During the 75 years that have passed since then, only six additional specimens of the family have been found (Carpenter, 1938, 1944; Richardson, 1956), all of them in the Mazon Creek beds. The latest of these specimens was sent to me for study by Dr. E. S. Richardson, Jr., a few months before his death, and I have only recently had the opportunity to study it and prepare illustrations. While working on this fossil, I decided to reexamine at the same time the other five specimens in the family known to me. A review of these specimens is included here, followed by revised diagnoses of the family and of the two known genera.

Neurological manifestations of pediatric achondroplasia

1981 ◽  
Vol 54 (1) ◽  
pp. 49-57 ◽  
Author(s):  
Hiroshi Yamada ◽  
Shigetoshi Nakamura ◽  
Masataka Tajima ◽  
Naoki Kageyama
Keyword(s):  
Intracranial Pressure ◽  
Growth Curves ◽  
Jugular Foramen ◽  
Foramen Magnum ◽  
Cerebral Veins ◽  
Increased Intracranial Pressure ◽  
Content Type ◽  
Respiratory Problems ◽  
Number Of Patients ◽  
Small Foramen

✓ The neurological and neuroradiological manifestations of pediatric achondroplasia are analyzed on the basis of 10 cases. In addition to the classical symptomatology of an enlarging head, with or without increased intracranial pressure, several patients presented symptoms related to a small foramen magnum. Respiratory problems and quadriparesis were also observed in these patients. Six patients who were treated by foramen magnum decompression showed remarkable improvement. Neuroradiological evaluation revealed a significant number of patients with dilated cortical sulci and basal cisterns, and mild dilatation of the ventricles on computerized tomography (CT) and/or ventriculography. Two patients showed signs of obstruction at the fourth ventricle outlets. Some exhibited anomalous dilatation of cerebral veins and dural sinuses, narrowing of the sinuses at the jugular foramen, and enlarged emissary veins. Ventriculoperitoneal or ventriculoatrial shunts were placed in three patients. In the other children with a large head and dilated ventricles, head growth curves paralleled the normal slope, and there was no significant clinical evidence of increased intracranial pressure or enlarging ventricles on follow-up CT scan.

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