Intraluminal septation of the basilar artery: incidence and potential clinical significance.

Variations in the cerebrovascular tree can increase surgical or interventional morbidity. To date, only scant comments are to be found in the literature regarding intraluminal variations of the basilar artery. To further elucidate such anatomy, a cadaveric study was performed. One hundred and fifty human brains were evaluated for the present study. The basilar artery was identified in each and sectioned longitudinally to observe for the presence of intraluminal septa. One specimen (0.67%) was identified that harbored an intraluminal septum of the basilar artery. This wall was within the proximal basilar artery and measured 3 mm by 1.5 mm. No specimen was found to have other anomalies of the basilar artery and in the single specimen with an intraluminal septum no signs of intracranial pathology were seen. Although seemingly rare, septation of the basilar artery can be found. Knowledge of such an intraluminal vascular variation may be important during invasive and minimally invasive procedures.

The venous circle of Trolard.

A venous anastomotic network is occasionally found at the base of the brain, which closely resembles the vicinal arterial circle of Willis. When present, this venous polygon is composed of the anterior cerebral and communicating veins, the basal vein of Rosenthal and the posterior communicating and lateral mesencephalic veins. We propose that this anastomotic ring be termed the venous circle of Trolard. This venous circle might cause bleeding with such procedures as an endoscopic third ventriculostomy. We believe that information regarding this venous circle may be useful to neuroradiologists or neurosurgeons operating at the base of the brain (Fig. 1, Ref. 10). Full Text (Free, PDF) www.bmj.sk.

Indirect inguinal hernia of the urinary bladder through a persistent canal of Nuck: case report.

We report a 79-year-old female cadaver found to harbor an indirect inguinal hernia involving the urinary bladder. Further investigation revealed a patent canal of Nuck. The authors describe this rare finding in an adult and review the pertinent literature regarding such herniation. We believe this to be the first report of an indirect inguinal hernia involving the urinary bladder in a cadaver. This also seems to be the first description of such a hernia via a patent canal of Nuck in an adult.

Accessory venous sinus of Hyrtl.

Variations of the intracranial venous sinuses are important to the surgeon during intraoperative procedures and to the clinician during imaging interpretation. We report a male cadaver found to have a rare venous sinus variation. In all likelihood, this sinus corresponded to the rarely reported accessory venous sinus of Hyrtl. The sinus was approximately 5 mm in width and traveled from the sphenoparietal sinus anteriorly to the veins, draining into the foramen spinosum (i.e. the middle meningeal veins) posteriorly. No other variations or obvious pathology were identified intracranially or extracranially. Knowledge of such a venous variation may be of use to the clinician.

A complex dural-venous variation in the posterior cranial fossa: a triplicate falx cerebelli and an aberrant venous sinus.

Variations of the dural folds and the dural venous sinuses are seldom reported in the extant medical literature. Such variations in the posterior cranial fossa may be problematic in various diagnostic and operative procedures of this region. We report our observation of an extremely rare variation of the falx cerebelli and posterior cranial fossa venous sinuses encountered upon dissection of a young male cadaver. In this specimen the falx cerebelli was duplicated with dimensions of 45.3x5.1 mm and 49.8x5.3 mm for the right and left falces respectively. The distance between the two falces was 3.2, 4.5 and 7.8 mm at their proximal, middle and distal thirds. An accessory small falx (31.8x2 mm) was also found approximately 3.4 mm lateral to the right falx cerebelli and blended with the lateral surface of the right falx cerebelli. There was only one occipital venous sinus (diameter, 2.5 mm) and no marginal sinus was detected. At the right floor of the posterior cranial fossa (posterolateral to the foramen magnum) an additional dural venous sinus was found, which connected the terminal portion of the right sigmoid sinus to the occipital and right transverse sinuses via one medial and two lateral branches respectively. We believe that such a complex dural-venous variation in the posterior cranial fossa has not previously been reported. Neurosurgeons and neuroradiologists should be aware of such variations, as these could be potential sources of haemorrhage during suboccipital approaches or may lead to erroneous interpretations of imaging of the posterior cranial fossa.

Retrosplenic course of the transverse cervical artery with the suprascapular artery travelling through the suprascapular notch.

Anatomical variations of the transverse cervical and suprascapular arteries are common. We report an adult male cadaver found to harbour an unusual variation of the right course of these two arteries. The transverse cervical artery arose independently from the first segment of the subclavian artery and passed deep to the anterior scalene muscle, a course which, to our knowledge, has not been reported before. Simultaneously, the ipsilateral suprascapular artery arose from the third segment of the subclavian artery and travelled posteriorly with the suprascapular nerve deep to the suprascapular ligament. We believe this is the first report of such a simultaneous occurrence.

Aortic bifurcation angle as an independent risk factor for aortoiliac occlusive disease.

Recently, there has been interest in potential geometric risk factors that might result in or exaggerate atherosclerosis. The aortic bifurcation is a complex anatomical area dividing the high pressure blood of the descending abdominal aorta into the lower limbs and pelvis. The distribution of the bifurcation angle and any asymmetry, its relation with age and its possible contribution to the risk of aortoiliac atherosclerosis are presented here. Statistical analysis was performed by SPSS version 11.0 using, Fisher;s exact test, the Pearson and Spearman correlation tests and logistic regression analysis. The p value was set at 0.05. No correlations were found between age, bifurcation angle and angle asymmetry in the Pearson test (p > 0.05). Logistic regression analysis revealed that the bifurcation angle, but not its asymmetry, gender or age, was a significant and independent risk factor for aortoiliac atherosclerosis (model r(2) = 0.662, p = 0.027). With additional study these results may have implications regarding risk factors for aortoiliac atherosclerosis. To our knowledge, this study is the first of its kind to indicate the potential of such an important geometric risk factor for atherosclerosis at the aortic bifurcation.

An unusual muscular variation of the infratemporal fossa.

The infratemporal fossa is often the site of pathology or surgical intervention. We describe an unusual muscle found during the routine dissection of the right infratemporal fossa. The literature germane to this variable muscle, best described as a variant of the pterygoideus proprius, is reviewed. The clinician may contemplate the wide array of muscular anomalies within the infratemporal fossa when considering unexplained neurological symptoms attributed to branches of V3 and pursue appropriate diagnostic testing.

An unreported variation of the cervical vagus nerve: anatomical and histological observations.

Variations involving the cervical portion of the vagus nerve are seemingly very rare. We report an adult male found to harbour a right cervical vagus nerve that crossed anterior to the right common carotid artery to terminate in the lateral aspect of the thyroid gland. A very small continuation of this nerve was found to continue distally into the thorax. Histologically, this part of the vagus nerve did not contain ganglion or other cell bodies. There were no heterologous inclusions (thyroid, parathyroid, thymus, salivary gland or branchial cleft remnants) present. Although grossly there was a connection into the thyroid gland, this was not observed histologically. No signs of trauma were found to the ipsilateral neck region. We hypothesise that this variation is due to entanglement between the thyroid gland and cervical vagus nerve during development. This rare variation might be considered by the clinician who operates in the cervical region or interprets imaging of the neck. To our knowledge, a vagus nerve with the above described morphology has not been described.

Whole genomewide linkage screen for neural tube defects reveals regions of interest on chromosomes 7 and 10.

Neural tube defects (NTDs) are the second most common birth defects (1 in 1000 live births) in the world. Periconceptional maternal folate supplementation reduces NTD risk by 50-70%; however, studies of folate related and other developmental genes in humans have failed to definitively identify a major causal gene for NTD. The aetiology of NTDs remains unknown and both genetic and environmental factors are implicated. We present findings from a microsatellite based screen of 44 multiplex pedigrees ascertained through the NTD Collaborative Group. For the linkage analysis, we defined our phenotype narrowly by considering individuals with a lumbosacral level myelomeningocele as affected, then we expanded the phenotype to include all types of NTDs. Two point parametric analyses were performed using VITESSE and HOMOG. Multipoint parametric and nonparametric analyses were performed using ALLEGRO. Initial results identified chromosomes 7 and 10, both with maximum parametric multipoint lod scores (Mlod) >2.0. Chromosome 7 produced the highest score in the 24 cM interval between D7S3056 and D7S3051 (parametric Mlod 2.45; nonparametric Mlod 1.89). Further investigation demonstrated that results on chromosome 7 were being primarily driven by a single large pedigree (parametric Mlod 2.40). When this family was removed from analysis, chromosome 10 was the most interesting region, with a peak Mlod of 2.25 at D10S1731. Based on mouse human synteny, two candidate genes (Meox2, Twist1) were identified on chromosome 7. A review of public databases revealed three biologically plausible candidates (FGFR2, GFRA1, Pax2) on chromosome 10. The results from this screen provide valuable positional data for prioritisation of candidate gene assessment in future studies of NTDs.

Klippel-Feil anomaly with associated rudimentary cervical ribs in a human skeleton: case report and review of the literature.

Anomalies of the cervical spine are intriguing anatomically and often come to clinical attention. Fusion of one or more cervical vertebral segments, the Klippel- Feil anomaly (KFA), often causes increased motion at the vertebral segments superior to and inferior to the fused level with a resultant premature wear of these joints. We report an adult male skeleton with fusion of his C6 and C7 vertebral bodies (Type II KFA). A remnant of the intervertebral disc space was noted and bilateral rudimentary cervical ribs were observed emanating from the C7 vertebrae. Excessive joint degeneration was noted between the vertebral bodies of C5 and C6. Following our review of the literature and case report, it appears that there is an increased incidence of the presence of cervical ribs in KFA. We review the literature for coexistent KFA and cervical ribs and discuss their dysembryology.

The subanconeus muscle.

There is a paucity of information in the extant literature regarding the detailed anatomy of the subanconeus (articularis cubiti) muscle. Our current study seeks to elucidate further the presence, morphology, and potential function of this muscle. Eighteen cadaveric upper extremities underwent dissection of their posterior elbow joint capsule with special attention to any fibres attaching to it from the triceps brachii muscle. We found that all specimens had various amounts of muscular attachment of the medial head of the triceps into the posterior joint capsule. It was noted that the highest concentration of fibres was into the joint capsule near the groove for the ulnar nerve. No specimen was found to have a distinct muscle belly associated with these connections to the joint capsule. On all sides these fibres were simply deeper attachments of the medial head of the triceps brachii muscle. Following tension on these deeper fibres retraction of the joint capsule was not noted but rather compression of the capsule. We would speculate on the basis of our study that these fibres of the medial head of the triceps brachii muscle do not represent a separate muscle per se and do not retract the posterior elbow joint capsule with extension of the forearm as has been theorised. It is possible that compression of the posterior elbow joint capsule from these deeply placed fibres of the triceps brachii restricts the elbow fat pad from being displaced and allows it to cushion the contact made between the olecranon process and the olecranon fossa.

Malignant fibrous histiocytoma of the spermatic cord: a case report and review of the literature.

Malignant fibrous histiocytoma (MFH) is a morphologically ill-defined tumour of the soft tissues and may involve nearly every organ of the body. MFH of the spermatic cord represents an extremely rare entity and reports of it in the literature are limited. We report a 69-year-old man found to have a left spermatic cord MFH and retroperitoneal and mediastinal lymphadenopathy, who was treated with radical orchiectomy and adjuvant chemotherapy. The morphological findings of the spermatic tumour are presented and the literature is reviewed to clarify the potential diagnostic/therapeutic approaches and the prognosis related to spermatic cord MFH.

Does a third head of the rectus femoris muscle exist?

Current anatomical texts describe only two tendinous origins of the rectus femoris muscle. The authors identified one older reference in which a third head of the rectus femoris muscle was briefly described. In order to confirm the existence of this head, 48 adult cadavers (96 sides) underwent detailed dissection of the proximal attachments of the rectus femoris muscle. Of these sides 83% were found to harbour a recognised third head of the rectus femoris muscle. This additional head was found to attach deeply to the iliofemoral ligament and superficially with the tendon of the gluteus minimus muscle as it attached into the femur. This tendon attached to the anterior aspect of the greater trochanter in an inferolateral direction compared to the straight head. The mean length and width of the third head was 2 cm and 4 cm, respectively. The mean thickness was found to be 3 mm. Most commonly this third head was bilaterally absent or bilaterally present. However, 4.2% were found only on left sides and 5.2% were found only on right sides. The angle created between the reflected and third heads was approximately 60 degrees. Two sides (both left sides with one female and one male specimen) were found to have third heads that were bilaminar. These bilaminar third heads had a distinct layer attaching to the underlying iliofemoral ligament and a superficial layer blending with the gluteus minimus tendon to insert onto the greater trochanter. Although the function of such an attachment is speculative, the clinician may wish to consider this structure in the interpretation of imaging or in surgical procedures in this region, as in our study it was present on the majority of sides.

Bilateral accessory middle cerebral arteries associated with an aneurysm of the anterior circulation.

An accessory middle cerebral artery is one variation of the intracranial vasculature that may be a source of misinterpretation by clinicians dealing with cerebrovascular diseases. We report a case of an elderly female found to have bilateral accessory middle cerebral arteries, who presented with the rupture of an aneurysm of the anterior part of the circle of Willis. Accessory middle cerebral arteries are rare anatomical findings and the bilateral occurrence is exceedingly rare. We believe this to be the first report of bilateral accessory middle cerebral arteries associated with an aneurysm of the anterior cerebral-anterior communicating arteries. The anatomical and clinical relevance of this variation is described.

The morphology and function of the quadrate ligament.

There is a paucity of information in the literature regarding the quadrate ligament and the information that does exist is extremely conflicting. We dissected 30 cadavers (60 sides) to determine the morphology and function of this enigmatic ligament. A quadrate ligament (thickening of the elbow joint capsule) was found in all specimens. In all specimens this band was distinct from the circumferential fibres of the annular ligament. The length, width, and thickness of the quadrate ligament were found to be 11 mm, 8 mm, and 1 mm respectively. This ligament not only aided in securing the neck of the radius to the ulna but also resisted excessive supination and, to a lesser degree, pronation of the forearm. Following transection of the quadrate ligament, the head of the radius was secured to the ulna considerably less firmly and supination and pronation increased by 10 to 20 degrees and 5 to 8 degrees respectively. The quadrate ligament contributes to proximal radioulnar stability, limits the "spin" of this joint, and should be considered in manipulation, surgery, or imaging of the proximal forearm.

Amplification of the c-myc gene in human medulloblastoma cell lines and xenografts.

Cultured cell lines and xenografts derived from 7 human medulloblastomas were evaluated for amplification of the c-myc, N-myc, epidermal growth factor receptor, and gli genes by Southern blot analysis. Karyotypes of the original biopsies and early passaged cells demonstrated double minute chromosomes in 4 of the 7 cases. All 7 samples (3 cell lines and 4 xenografts) from the 4 tumors with double minute chromosomes contained amplification of the c-myc gene. Cell lines and xenografts derived from the 3 biopsies without double minute chromosomes failed to demonstrate amplification of the 4 genes which were tested, but a rearrangement of the c-myc gene occurred in 1 of the 3 tumors. These observations demonstrate that the c-myc gene is often amplified and/or rearranged in human medulloblastomas and suggest that amplification of this gene provides a growth advantage for medulloblastoma cells in vitro and in vivo.

Treatment of children with progressive or recurrent brain tumors with carboplatin or iproplatin: a Pediatric Oncology Group randomized phase II study.

PURPOSE: The Pediatric Oncology Group (POG) conducted a randomized phase II study to evaluate the activity of carboplatin and iproplatin in children with progressive or recurrent brain tumors. PATIENTS AND METHODS: The study was designed to evaluate the activity of these agents and to compare the toxicities associated with their use. Treatment consisted of carboplatin 560 mg/m2 at 4-week intervals or iproplatin 270 mg/m2 at 3-week intervals. RESULTS: The major toxicity observed was myelosuppression, particularly thrombocytopenia, for both agents. Ototoxicity (grade 1 or 2) was seen in 2.5% of patients treated with carboplatin and 1.3% of patients treated with iproplatin. The majority of patients with low-grade astrocytic neoplasms treated with carboplatin (nine of 12 patients) or iproplatin (eight of 12 patients) demonstrated tumor response or prolonged stable disease that persisted off-therapy. The duration of stable disease produced by carboplatin was particularly striking, ranging from 2 months to 68 + months (median, 40 + months). Neither drug demonstrated appreciable activity in the treatment of medulloblastoma (two of 26 responses to carboplatin, one of 14 responses to iproplatin), ependymoma (two of 17 responses to carboplatin, none of seven responses to iproplatin), high-grade glioma (two of 19 responses to carboplatin, one of 14 responses to iproplatin), or brain-stem tumors (one of 23 responses to carboplatin, none of 14 responses to iproplatin). CONCLUSION: Carboplatin is active against low-grade gliomas. Further evaluation of the role of carboplatin in the preirradiation treatment of children with low-grade gliomas of the optic pathway is currently underway in a clinical trial.

Phase II treatment of medulloblastoma and pineoblastoma with melphalan: clinical therapy based on experimental models of human medulloblastoma.

We conducted a phase II study of intravenous (IV) melphalan in the treatment of children with recurrent medulloblastoma and in the initial treatment of children with poor-prognosis medulloblastoma and pineoblastoma. There was one complete response (CR) and two partial responses (PRs) among the 12 children with recurrent medulloblastoma. There were three PRs in the four patients initially treated with melphalan for poor-prognosis medulloblastoma or pineoblastoma. Toxicity was limited to severe myelosuppression with marked neutropenia and thrombocytopenia. These results support our laboratory studies demonstrating melphalan activity in human medulloblastoma, suggest that similar activity may be demonstrated against pineoblastoma, and support further trials with this agent (administered prior to radiotherapy) in the treatment of patients with newly diagnosed poor-prognosis medulloblastoma.

Quantitative anatomy of the posterior cricoid region.

The anatomy of the posterior cricoid cartilage region was examined to obtain a better quantitative understanding of this region. The mean height and width of the posterior cricoid cartilage in the midline measured 24.5 mm and 25 mm respectively. The mean distance between the fibres for the left and right posterior cricoarytenoid muscles was 5 mm at the midpoint of the posterior cricoid cartilage. The height of these muscles averaged 19 mm for left sides and 20 mm for right sides. The mean distances from the midpoint and superior midline of the posterior cricoid cartilage to the inferior laryngeal nerve were 14 mm and 15 mm respectively for left sides and 17 mm and 18 mm respectively for right sides. It is hoped that these data will be of use to clinicians performing invasive procedures in this area.