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Background The inferolateral triangle is a surgical skull base triangle used as a neurosurgical landmark. There are few reports of its measurements with little attention paid to anatomic variations. Methods The inferolateral triangle was measured in 10 adult human cadaveric heads via dissection then direct measurement and 5 participants undergoing neuroimaging using tracing features. Results In the cadavers, mean lengths (mm) of the superior, anterior, and posterior borders were 17.0 (±5.5), 12.9 (±1.7), and 17.8 (±3.3), respectively, with mean area of 97.85 (±28.17) mm2. In the participants, mean lengths (mm) of the superior, anterior, and posterior borders were 17.35 (±4.01), 14.36 (±1.36), and 18.01 (±2.43), respectively, with mean area of 113.6 (±25.46) mm2. No statistical difference in triangle areas between groups was found. Conclusions Intimate understanding of the inferolateral triangle is essential to skull-based surgery; knowing its anatomy and variations aids in surgical planning and understanding of regional pathology.

Lupus panniculitis (LP), also referred to as lupus erythematosus profundus (LEP), is a chronic recurrent inflammation condition of the subcutaneous fat. It occurs in 1 to 3% of patients with systemic lupus erythematosus (SLE) and in 10% of patients with discoid lupus erythematosus (DLE), but can also occur as an entity of its own. Patients with lupus panniculitis usually present with persistent, often tender and painful skin lesions, or subcutaneous nodules, that range from 1 to 5 cm in diameter. The overlying skin may appear erythematous; lesions may become ulcerated, and heal with atrophy, skin depression, dimpling and scaring. Lesions tend to resolve spontaneously and may follow a chronic course of remission and exacerbation that persists for months to years. The imaging features of facial LP are extremely scarce in the literature. We present a case of facial lupus panniculitis and describe the associated characteristic ultrasound, CT, and MR imaging findings along with histopathologic correlation.

The anterolateral triangle is one of 10 surgical triangles of the cavernous sinus and serves as an important anatomic landmark for the skull base surgeon. There are few studies in the English literature that have precisely defined and measured the borders of the anterolateral triangle and little agreement has been made regarding the nomenclature within the English literature. A total of 12 midsagittally hemisected adult human cadaveric head halves were dissected to expose the anterolateral triangle. The triangle was defined and measurements of the anterior, posterior, and lateral borders were taken. The mean lengths and standard deviations of the anterior, posterior, and lateral borders were 8.3 ± 2.2 mm, 5.9 ± 2.0 mm, and 11.5 ± 2.9 mm, respectively. The mean area and standard deviation were 20.46 ± 9.30 mm2. The anterolateral triangle is helpful in understanding and planning surgical approaches to the cavernous sinus and middle cranial fossa. As such, normal anatomic relationships and the sizes of the anterolateral triangle must first be recognized to better access the pathologic changes within and around this region.

Cerebral artery fenestrations are usually detected incidentally during angiography, have a reported incidence ranging from of 0.03% to 1%, and rarely cause neurological symptoms. They can, however, be associated with aneurysmal dilatation at the proximal or distal end of the fenestration, cerebral arteriovenous malformations, or (rarely) ischemic symptoms. We present a case of a 54-year-old obese woman who presented with a large convex-lens-like fenestration of the right middle cerebral artery (MCA) at the M1 segment (distal to the origin of the temporopolar artery) associated with a transient ischemic attack. The MCA fenestration caused a local change in hemodynamic blood flow, which leads to cerebral ischemia. Magnetic resonance angiography (MRA) also revealed an associated small slit-like fenestration of the basilar artery (BA), hypoplasia of the A1 segment of the right anterior cerebral artery, bilateral fetal posterior cerebral arteries, and bilateral absence of the posterior communicating arteries. To our knowledge, this is the sixth reported case of MCA fenestration with an associated ischemic attack. In our case, fenestrations of the MCA, the BA, and hypoplasia of the A1 segment of ACA were not associated with any aneurysms.

The trigeminal artery is one of four primitive anastomoses between the internal carotid artery and vertebrobasilar system that regresses in the sixth week of fetal development. A persistent trigeminal artery (PTA) is generally an incidental finding but may also be associated with intracranial vascular pathologies such as aneurysms, arteriovenous malformations, and cranial nerve compression syndromes. We present an extremely rare case of a right PTA with an associated bleeding fusiform aneurysm located in the carotidian (lateral) part of the PTA. In addition, this rare anatomic variation was associated with bilateral absence of the posterior communicating arteries, a left posterior cerebral artery originating from the left internal carotid artery, and agenesis of the A1 segment of the left anterior cerebral artery.

Objectives The roof of the porus trigeminus, composed of the posterior petroclinoid dural fold, is an important landmark to the skull base surgeon. Ossification of the posterior petroclinoid dural fold is an anatomical variation rarely mentioned in the literature. Such ossification results in the trigeminal nerve traversing a bony foramen as it enters Meckel cave. The authors performed this study to better elucidate this anatomical variation. Design Fifteen adult cadaveric head halves were subjected to dissection of the middle cranial fossa. Microdissection techniques were used to examine the posterior petroclinoid dural folds. Skull base osteology was also studied in 71 dry human skulls with attention paid to the attachment point of the posterior petroclinoid dural folds at the trigeminal protuberances. Setting Cadaver laboratory Main Outcome Measures Measurements were made using a microcaliper. Digital images were made of the dissections. Results Completely ossified posterior petroclinoid folds were present in 20% of the specimens. Of the 142 dry skull sides examined, 9% had large trigeminal protuberances. Conclusions Based on this study, the posterior petroclinoid dural fold may completely ossify in adults that may lead to narrowing of the porus trigeminus and potential compression of the trigeminal nerve at the entrance to Meckel cave.

We present a rare case of a variant middle meningeal artery (MMA) originating from the ophthalmic artery. During cadaveric dissection of the cranial base of an adult female, it was noted that the foramen spinosum was absent unilaterally. After identifying the MMA, its origin was traced back to the ophthalmic artery within the orbit. Although exceedingly rare, a variant MMA originating from the ophthalmic artery should be kept in mind by surgeons during skull base procedures in order to avoid unwanted complications including potential retrograde thrombosis of the ophthalmic artery with MMA manipulation or coagulation.

Human chromosome 16 features one of the highest levels of segmentally duplicated sequence among the human autosomes. We report here the 78,884,754 base pairs of finished chromosome 16 sequence, representing over 99.9% of its euchromatin. Manual annotation revealed 880 protein-coding genes confirmed by 1,670 aligned transcripts, 19 transfer RNA genes, 341 pseudogenes and three RNA pseudogenes. These genes include metallothionein, cadherin and iroquois gene families, as well as the disease genes for polycystic kidney disease and acute myelomonocytic leukaemia. Several large-scale structural polymorphisms spanning hundreds of kilobase pairs were identified and result in gene content differences among humans. Whereas the segmental duplications of chromosome 16 are enriched in the relatively gene-poor pericentromere of the p arm, some are involved in recent gene duplication and conversion events that are likely to have had an impact on the evolution of primates and human disease susceptibility.

Chromosome 19 has the highest gene density of all human chromosomes, more than double the genome-wide average. The large clustered gene families, corresponding high G + C content, CpG islands and density of repetitive DNA indicate a chromosome rich in biological and evolutionary significance. Here we describe 55.8 million base pairs of highly accurate finished sequence representing 99.9% of the euchromatin portion of the chromosome. Manual curation of gene loci reveals 1,461 protein-coding genes and 321 pseudogenes. Among these are genes directly implicated in mendelian disorders, including familial hypercholesterolaemia and insulin-resistant diabetes. Nearly one-quarter of these genes belong to tandemly arranged families, encompassing more than 25% of the chromosome. Comparative analyses show a fascinating picture of conservation and divergence, revealing large blocks of gene orthology with rodents, scattered regions with more recent gene family expansions and deletions, and segments of coding and non-coding conservation with the distant fish species Takifugu.

About 10% of the nalidixic acid-resistant (Nal r ) mutants in a transposition-induced library exhibited a growth factor requirement as the result of cysH , icdA , metE , or purB mutation. Resistance in all of these mutants required a functional AcrAB-TolC efflux pump, but the EmrAB-TolC pump played no obvious role. Transcription of acrAB was increased in each type of Nal r mutant. In the icdA and purB mutants, each of the known signaling pathways appeared to be used in activating the AcrAB-TolC pump. The metabolites that accumulate upstream of the blocks caused by the mutations are hypothesized to increase the levels of the AcrAB-TolC pump, thereby removing nalidixic acid from the organism.