Posterior Part Of Body Research Articles

Ektaphelenchoides factum n. sp. in Pinus taeda from the USA and E. pini in Pinus koraiensis from China

Summary The genus Ektaphelenchoides is a diverse group of nematodes; they are either inhabitants of trees or present in the rhizosphere of economical plants. Members of the genus have ecological relevance in terms of being associated with insects and predators of other nematodes. In the present study, a new Ektaphelenchoides species, E. factum n. sp., is described and illustrated. The new species was isolated from a log sample of Pinus taeda imported from the USA. It is characterised by the lateral field with three incisures, stylet distinctly tripartite. Females having a vulval flap, the anus and rectum indistinct, and the tail (posterior part of body) filiform. Males having arcuate and 21.5 (19.4-22.9) μm long spicules, the lamina of the spicule is smoothly curved to distal end, condylus well developed with a broadly rounded tip, rostrum triangular with finely rounded tip and cucullus absent, tail arcuate and conical with terminus bearing a sharply pointed mucron. The new species is different from other Ektaphelenchoides species in having a vulval flap. Molecular characterisation and phylogenetic studies also supported its unique status. In addition, a Chinese native population of E. pini, detected in Pinus koraiensis branches from Liaoning province, P.R. China, is described.

Morphological, histological and gene-expression analyses on stolonization in the Japanese Green Syllid, Megasyllis nipponica (Annelida, Syllidae)

Benthic annelids belonging to the family Syllidae (Annelida, Errantia, Phyllodocida) exhibit a unique reproduction mode called “schizogamy” or “stolonization”, in which the posterior body part filled with gametes detaches from the original body, as a reproductive unit (stolon) that autonomously swims and spawns. In this study, morphological and histological observations on the developmental processes during stolonization were carried out in Megasyllis nipponica. Results suggest that the stolon formation started with maturation of gonads, followed by the formation of a head ganglion in the anteriormost segment of the developing stolon. Then, the detailed stolon-specific structures such as stolon eyes and notochaetae were formed. Furthermore, expression profiles of genes involved in the anterior–posterior identity (Hox genes), head determination, germ-line, and hormone regulation were compared between anterior and posterior body parts during the stolonization process. The results reveal that, in the posterior body part, genes for gonadal development were up-regulated, followed by hormone-related genes and head-determination genes. Unexpectedly, Hox genes known to identify body parts along the anterior–posterior axis showed no significant temporal expression changes. These findings suggest that during stolonization, gonad development induces the head formation of a stolon, without up-regulation of anterior Hox genes.

Two New Species of Free-Living Marine Nematode of the Genus Anticyathus Cobb, 1920 (Linhomoeidae) from Mangroves Sediment of Shenzhen and Shantou, China

Two new species belonging to the genus Anticyathus were discovered during an ecological investigation of mangrove sediment in China. Anticyathus shenzhensis sp. nov. and Anticyathus communis sp. nov. are both characterized by: annulated cuticles; ten cephalic setae in a circle; buccal cavity lined with six longitudinal reinforcements; amphids in broken circles or cryptic spirals, located at the very anterior of the head; pharynx with anterior cuticularized, gradually enlarging in posterior portion but without bulb; conical tail; arcuate spicules, the distal ends pointed, gradually broadening towards the proximal; gubernaculum has a dorsal–caudal apophysis; female with two opposed, outstretched ovaries. Anticyathus shenzhensis sp. nov. can be distinguished by ten cephalic setae of length about 2–4 µm; amphids diameter about 20–29% of corresponding body diameter; pharynx occupy 0.07–0.10 times of body length; cardia length about 25 µm; tail length 2.5–3.4 times of anal body diameter (abd) in males and 3.4–4.7 abd in females; spicules length 51–59 µm as arc and 0.71–1.04 abd; apophysis length 18–19 µm; female vulva at 52–56% of body length. Anticyathus communis sp. nov. is identified by ten cephalic setae length about 3–5 µm; amphids diameter about 20–32% of corresponding body diameter; cardia 17–27 µm long; tail length 3.6–4.5 abd in male, 5.3–5.5 abd in female; spicules proximal with distinctly cephalated, 0.74–0.96 abd; gubernaculum shape of “L”, consisting of sleeves around spicule and dorsal–caudal apophysis; five to seven pre-anal and seven to ten post-anal almost invisible papilla or papillae-like setae occur on each ventrally submedian line on the posterior body part of male; the tip of male tail with three slight elevation; female vulva at 52% of body length. A dichotomous key for the genus Anticyathus is given and 39 sequences of 18S rRNA gene from ten individuals of Anticyathus shenzhensis sp. nov. are provided in Genbank database.

Imaging features inferring symptom onset due to spinal metastasis progression: a preliminary study.

Spinal metastases can cause intractable pain and neurological deficits, which can markedly worsen both patients' activities of daily living (ADL) and their health-related quality of life (QOL). Early intervention is essential to prevent irreversible neurological deficits and pain associated with spinal metastases. We investigated the imaging features of spinal metastases that led to neurological deficits. We analyzed axial cross-sectional computed tomography (CT) images of cervical and thoracic spinal metastases in patients with and without lower limb motor paralysis, neuropathic pain, and local nociceptive pain. We distinguished regions of the spine associated with these respective symptoms, and explored their inferable performance using images obtained before symptom onset. In addition, we analyzed the imaging features and type of bone metastasis (osteolytic and osteoblastic). Spinal lesions occupied the area in and around the spinal canal and around the pedicle in patients with motor paralysis. Lesions around the pedicle and in the most posterior vertebral body part before symptom onset were inferable. In patients with neuropathic pain, spinal metastases spread along the pedicle before symptom onset, and had surrounded the spinal canal circumferentially at symptom onset. Local nociceptive pain was more common near the center of the vertebral body either at or before symptom onset. There was no difference in the imaging features according to the type of bone metastasis. Lesions in certain regions in the asymptomatic metastatic spine can indicate the onset of spinal metastasis-related symptoms in the next few months. Early therapeutic intervention might be applied to prevent neurological disorder.

Treatment of osteoporotic vertebral compression fractures by unilateral puncture through the posterior outer upper part of the vertebral body

Objective: To comprehensively analyze the effect of unilateral and bilateral puncture in the treatment of osteoporotic vertebral compression fractures (OVCFs).Methods: The main subjects of this study were: OVCFs patients (a total of 100 cases, starting from October 2020 and ending from October 2021). According to the different treatment methods, two groups (50 cases in each group) were named, one group was the control group (applying bilateral puncture treatment through the vertebral body), the other group was the experimental group (unilateral puncture treatment through the vertebral body).Results: Compared with the control group, the operation time of the experimental group was shorter, P < 0.05; Compared with the control group, the amount of intraoperative blood loss in the experimental group was less, P < 0.05; Compared with the control group, the amount of bone cement filling and X-ray exposure in the experimental group were significantly less, P < 0.05; Compared with the control group, there was no difference in bone cement leakage rate in the experimental group (P > 0.05). Before treatment, compared with the control group, there were no differences in Cobb Angle, pain degree score, spinal dysfunction score and quality of life score between the experimental group and the control group, P > 0.05; After treatment, compared with the control group, the quality of life score of the experimental group was higher, P < 0.05; Compared with the control group, the Cobb Angle, pain degree score and spinal dysfunction score of the injured vertebrae in the experimental group were lower, P < 0.05.Conclusion: Unilateral puncture through posterior and upper vertebral body is more effective than bilateral puncture in OVCFs patients.

Studying Annelida Body Regeneration Under Environmental Stress in Diopatra neapolitana.

The polychaete Diopatra neapolitana is a cosmopolitan annelid that can robustly regenerate both its anterior and posterior body part depending on the position of the amputation. Previous studies demonstrated that body regeneration represents a sensitive and unspecific response to environmental stresses, including contaminants and climate alterations.The posterior body regeneration of D. neapolitana is thus a suitable, ecological and relevant biomarker in ecotoxicological and ecological risk assessment assays. Here we describe the amputation process, the monitoring of the regeneration process of the polychaete D. neapolitana and the quantification of the impact of environmental stresses on its regenerative capacity.

Biomechanics of the medial meniscus in the osteoarthritic knee joint.

BackgroundIncreased mechanical loading and pathological response of joint tissue to the abnormal mechanical stress can cause degradation of cartilage characteristic of knee osteoarthritis (OA). Despite osteoarthritis is risk factor for the development of meniscal lesions the mechanism of degenerative meniscal lesions is still unclear. Therefore, the aim of the study is to investigate the influence of medial compartment knee OA on the stress state and deformation of the medial meniscus.MethodsThe finite element method was used to simulate the stance phase of the gait cycle. An intact knee model was prepared based on magnetic resonance scans of the left knee joint of a healthy volunteer. Degenerative changes in the medial knee OA model were simulated by nonuniform reduction in articular cartilage thickness in specific areas and by a decrease in the material parameters of cartilage and menisci. Two additional models were created to separately evaluate the effect of alterations in articular cartilage geometry and material parameters of the soft tissues on the results. A nonlinear dynamic analysis was performed for standardized knee loads applied to the tibia bone.ResultsThe maximum von Mises stress of 26.8 MPa was observed in the posterior part of the medial meniscus body in the OA model. The maximal hoop stress for the first peak of total force was 83% greater in the posterior horn and only 11% greater in the anterior horn of the medial meniscus in the OA model than in the intact model. The reduction in cartilage thickness caused an increase of 57% in medial translation of the medial meniscus body. A decrease in the compressive modulus of menisci resulted in a 2.5-fold greater reduction in the meniscal body width compared to the intact model.ConclusionsHigher hoop stress levels on the inner edge of the posterior part of the medial meniscus in the OA model than in the intact model are associated with a greater medial translation of the meniscus body and a greater reduction in its width. The considerable increase in hoop stresses shows that medial knee OA may contribute to the initiation of meniscal radial tears.

Does the Atlantic horse mackerel Trachurus trachurus (Teleostei: Carangidae) differentiate morphologically within the putative Moroccan-Saharan stock?

ABSTRACT To discriminate potential stock units of the Atlantic horse mackerel Trachurus trachurus within the putative Moroccan–Saharan stock, we investigated the morphological variation of this species from three fishing areas (from the north to the south: Larache, Safi and Dakhla) in the Moroccan Atlantic coastal waters. We used a geometric morphometric approach based on 30 truss measures derived from 14 landmarks in 165 fish specimens. We compared fish from three areas using a multivariate analysis including discriminant analysis and Procrustes technique. We found indications of at least two subunits: a differentiated subgroup in the north off Larache, probably a self-recruiting population or a locally adapted morphotype, and two overlapped subunits, respectively in the mid and southern Moroccan Atlantic coast off Safi and Dakhla. Examination of the contribution of each morphometric variable to canonical functions indicated that differences among samples seemed to be associated with morphological changes in the anterior and posterior parts of body, which may indicate adaptations to local environmental conditions and habitat use. Further investigations using other methods are needed to confirm the identified stock units. The present study and the obtained results on such a vulnerable declining small pelagic species are of great importance for fish stock assessment management and practice, but also have ecological and evolutionary implications related to local adaptations in fish populations that are under intense fishing pressure as an induced evolutionary selective force, which affects several adaptive traits.

The serotonergic nervous system of prolecithophorans shows a closer similarity to fecampiids than to triclads (Platyhelminthes).

Prolecithophora is a poorly studied flatworm order belonging to the adiaphanidan clade, together with Tricladida and Fecampiida. The phylogenetic position of the three orders within this clade is not yet resolved. Additionally, no obvious synapomorphy other than an opaque epidermis could be found so far. In this study, the serotonergic nervous system of six different prolecithophoran species has been studied for the first time with a fluorescent immunocytochemical technique. We found that all six species show a similar pattern of the serotonergic nervous system. The typical prolecithophoran serotonergic nervous system consists of a cephalic ganglion in the anterior body part from which a pair of dorsal, ventral, and lateral longitudinal nerve cords originate. Furthermore, the three longitudinal nerve cords of one body side are connected to each other at the posterior body part by a conspicuous commissure. The ventral cords, which we consider the main cords, are most prominent and show double brain roots. A comparison of the nervous system within Adiaphanida shows clearly that prolecithophorans and fecampiids are much more similar in this regard than prolecithophorans and triclads.

Spinal Intraosseus Schwannoma: A Case Report

Introduction: Schwannomas are the most frequent extramedullary intradural spinal tumors, accounting for approximately 24% of all nerve sheath tumors in adults. In a lower percentage of cases they may be extradural or transdural (1-19%). Intramedullary schwannomas and intraosseous schwannoma are quite rare tumors representing. Case Description: A 74-year-old woman presented intense low back pain for a few months, associated with left cruralgia and dysesthesia spread to both lower limbs. Magnetic resonance and computed tomography examination demonstrated an extramedullary intradural osteolytic lesion located in the posterior part of the vertebral body and pedicles of L1. The patient underwent a first surgery 4 years earlier with complete removal of the tumor but after about two years she had a recurrence. She was then subjected to a new intervention of decompression, removal of the tumor and arthrodesis. The histological findings were compatible with a classical schwannoma characterized by intraosseous growth and multifocal bone infiltration. Conclusion: We reported a rare case of intraosseous schwannoma presenting as a recurrence four years after radical surgical removal of a classic lumbar schwannoma. Only 25 cases of these tumors have been previously reported and none of them as an intraosseous recurrence.

Regeneration in Annelids: Cell Sources, Tissue Remodeling, and Differential Gene Expression

Recent studies have shown that, despite stereotypical cleavage, annelids show the ability for embryonic regulation, including the formation of germline cells. However, the widest variety of regulative processes is presented in the postlarval development of annelids. The ability to regenerate, which is probably an ancestral feature, manifests itself variously among these animals. Some species are unable to regenerate lost segments. However, most species replace lost posterior body parts, many are able to reestablish missing head segments and structures, and some develop the entire body de novo even on the basis of one or two segments. Most of the regenerated structures are formed due to a set of undifferentiated cells arising from the division of dedifferentiated and/or stem cells. Moreover, the regeneration process often involves remodeling of survived body fragments and may thus be associated not only with local changes but also require a response at the level of the whole organism. In this review, we summarize many recent studies on the molecular and cellular mechanisms of regeneration in annelids. Special attention is paid to the regeneration of the digestive and nervous systems and integuments as well as to the involvement of stem and undifferentiated cells in the development of blastema and in replacing the lost gonads. Accumulation and analysis of recent findings about the diversity of cellular sources and mechanisms of annelid regeneration may shed light on the most evolutionarily conserved programs for maintaining regeneration ability and processes leading to the loss (limitation) of one of the ancestral features of animals.

Biphasic moult cycle of the parasitic isopod Norileca indica (H. Milne Edwards, 1840) (Isopoda: Cymothoidea): stage-wise characterisation and haemolymph ecdysteroids titre

AbstractNorileca indica (H. Milne Edwards, 1840) is a protandrous hermaphroditic and obligatory parasitic isopod of scombrid fishes. The posterior and anterior biphasic moult cycles in the adult phases (male, transitional, and female) of this species are characterised based on the microscopic changes reflected in the uropod exopodite and maxillule, respectively. Biphasic parturial moult as well as the moult removing the old brood pouch characteristic of ovigerous females was recorded. Assay of haemolymph ecdysteroids titre with respect to different biphasic moult cycle stages appears to be first report of its kind among aquatic and/or parasitic isopods. The ecdysteroids titre showed significant fluctuation in relation to the moult cycle stages, while the parasite was at a biphasically intermoult stage, titre was estimated to be 13.64 ± 2.09 ng ml–1. By the onset of the premoult at the posterior body region, titre showed a gradual increase and reached a maximum level (328.54 ± 70.17 ng ml–1; P = 0.0060) when the parasite was at late premoult at the posterior body part and mid premoult stage at the anterior body part. There was a subsequent sharp decline (92.8 ± 12.95 ng ml–1; P = 0.002) soon after the ecdysis of the posterior part by the time premoult changes in the anterior part advanced as late premoult and about to moult. The level of ecdysteroids titre was 55.56 ± 14.47 ng ml–1 when the parasite completed anterior ecdysis and reached postmoult. Data on the monthly occurrence of biphasic moult cycles revealed that a mean average of 23.26% of the adult population undergoes premoult/ecdysis/postmoult activities throughout the year. The rate of moulting showed a decline (16.12 ± 0.60%) during the monsoon months (June-August) when compared to pre-summer/summer (February-May) (24.83 ± 2.42%) and post-monsoon/winter (September-January) (26.28 ± 1.75; P = 0.005).

Asymmetrical hybridization and gene flow between Eisenia andrei and E. fetida lumbricid earthworms.

Uniformly pigmented Eisenia andrei (Ea) and striped E. fetida (Ef) lumbricid earthworms are hermaphrodites capable of self-fertilization, cross-fertilization, and asymmetrical hybridization. The latter was detected by genotyping of F1 and F2 progeny of the controlled Ea+Ef pairs by species-specific sequences of maternal mitochondrial COI genes and maternal/paternal nuclear S28 rRNA genes. Among F1offspring there were self-fertilized Ea (aAA), Ef (fFF), and cross-fertilized fertile Ea-derived hybrids (aAF); the latter mated with Ea and gave new generation of Ea and hybrids, while mated with Ef gave Ea, Ef, Ea-derived hybrids and sterile Ef-derived hybrids (fFA). Coelomic fluid of Ea exhibits unique fluorescence spectra called here the M-fluorescence considered as a molecular biomarker of this species. Since similar fluorescence was detected also in some Ef (hypothetical hybrids?), the aim of present investigations was to identify the M-positive earthworms among families genotyped previously. It was assumed that factor/s responsible for metabolic pathways leading to production of undefined yet M-fluorophore might be encoded/controlled by alleles of hypothetical nuclear gene of Eisenia sp. segregating independently from species-specific S28 rRNA nuclear genes, where ‘MM’ or ‘Mm’ alleles determine M-positivity while ‘mm’ alleles determine M-negative phenotypes. Spectra of M-fluorescence were detected in all 10 Ea (aAAMM) and 19 Ea-derived hybrids (aAFMm), three of four Ef-derived hybrids (fFAMm) and one ‘atypical’ Ef (fFFMm) among 13 Ef earthworms. Among progeny of ‘atypical’ M-positive Ef (fFFMm) reappeared ‘typical’ M-negative Ef (fFFmm), confirming such hypothesis. Alternatively, the M-fluorescence might be dependent on unknown gene products of vertically-transmitted Ea-specific symbiotic bacteria sexually transferred to the Ef partner. Hypotheses of intrinsic and external origin of M-fluorescence might complement each other. The presence/absence of M-fluorophore does not correspond with body pigmentation patterns; Ef-characteristic banding appeared in posterior parts of hybrids body. In conclusion, Ea/Ef hybridization may serve for further studies on bi-directional gene flow.

Vascular Anomalies of Posterior Fossa and Their Implications.

Posterior fossa houses very vital and sensitive structures namely midbrain, pons, medulla, and cerebellum. These structures are irrigated by vertebral, posterior inferior cerebellar, anterior inferior cerebellar, and superior cerebellar arteries. Parts of brain located in posterior fossa control important parts of body so any variation pertaining to stenosis, atresia, hypoplasia, fenestration, agenesis, and duplication in the arteries supplying these parts alter the irrigation pattern culminating into various morbid and mortal neurologic disorders. Therefore, a sound understanding and thorough knowledge of posterior circulation vascular variant anatomy builds the foundation for the accurate diagnosis and appropriate management of neurovascular ischemic and hemorrhagic diseases of posterior fossa. To aid in addressing these complex neurologic disorders and neurosurgical treatment to be carried out successfully, updating and consolidating the knowledge of all the variations/insults of these arteries becomes essential. Therefore, review study has been carried out.Literature search was carried out using databases, including Scielo, Scopmed, Medline, PubMed, and Wiley online library. Papers containing original data were selected and secondary references retrieved from bibliographies. Search terms used were posterior fossa, anomalies of vertebral, posterior inferior cerebellar, anterior inferior cerebellar, and superior cerebellar arteries.The study will be of paramount importance to angiographers in interpreting angiographs, neurologists in diagnosis and treatment of neurologic disorders, and neurosurgeons in performing surgery in posterior fossa and craniovertebral region particularly dealing with tumors and vascular malformations.

Thermal experience improvement and thermal requirement difference in bed warming conditions

The human body is exposed to nonuniform thermal environment due to asymmetric bedding coverage of head and covered body. The purpose of the study is to investigate the thermal requirement difference of local body parts during sleep. Experiments were performed both in bed warming and non-bed warming conditions. Twelve healthy postgraduates were recruited as subjects. The thermal states on different local body parts of subjects were obtained via objective measurement and subjective questionnaires. The results showed that thermal comfort during sleep in winter was not in accordance with the thermal neutral state. In order to achieve overall thermal comfort condition, discrepant thermal sensation should be kept be-tween the head and covered body, besides, the disparity in skin temperature was 1.5°C and in TSV was 0.5 between posterior and lateral body part. The study has implications in the energy saving design of the coupled sleeping thermal environment in winter.

The female cephalothorax of Stylops ovinae Noskiewicz &amp; Poluszyński, 1928 (Strepsiptera: Stylopida)

External and internal features of the female cephalothorax of the strepsipteran species Stylops ovinae (Stylopidae) are described in detail. Many derived features are closely related with the obligatory endoparasitism. A conspicuous characteristic is the secondary tagmosis with an anterior cephalothorax and a large, sack-shaped posterior body region. The cephalothorax comprises the head, thorax and anterior half of abdominal segment I and protrudes from the host’s abdomen. It contains the mouth and birth opening, vestiges of cephalic appendages, and most internal organs including the large Nassonov’s glands. The posterior body part contains mainly the reproductive organs. The constriction of abdominal segment I probably prevents the exposed anterior body from slipping back into host’s body cavity. The narrow mouth opening is used for the uptake of the host’s hemolymph by the secondary larval stage and is maintained as a non-functional structure by the adult females. The tentorium is absent. The mandibles are immobilized in the adult female. They are used for penetrating the host’s body wall by the second larval instar. The brood canal formed by the larval and pupal exuvia is an autapomorphy of Stylopidia, the birth opening where the first instars are released from the female an autapomorphy of Stylopiformia, and the cephalothoracic invagination an autapomorphy of Stylops. A single pair of functional spiracles is laterally placed on abdominal segment I. An unusual circular hemolymph vessel is present in the pharyngeal region. The brain is shifted to the thorax. The suboesophageal complex and the thoracic and abdominal ganglia form a single ganglionic mass in the thoracic region. The musculature of the cephalothorax is extremely reduced. Nassonov’s glands, which produce sex pheromones, are the largest internal structures in the cephalothorax. Despite of the loss of the digestive function, the digestive tract is not degenerated including a foregut with well-developed muscles.

Morphological features of the tongue and laryngeal entrance in two predatory birds with similar feeding preferences: common kestrel (Falco tinnunculus) and Hume's tawny owl (Strix butleri).

The aim of this investigation was to describe the morphological characters of the tongue of two predatory birds with similar feeding preferences, i.e. the common kestrel and Hume's tawny owl. Descriptive information on the lingual morphology of these two birds, particularly Hume's tawny owl, is incomplete. We found that the lingual apex of the owl has an oval, concave, shovel-like form with a bifid lingual tip, while that of the kestrel has the shape of a horny tip-like spoon with a central process in addition to there being several filiform-like papillae on the dorsal surface of the apex and body. In the owl, the dorsal surface of the apex and body is subdivided into four U-shaped regions: lingual tip, two lateral regions and a median region. The two lateral regions are characterized by the presence of papillae and several openings of lingual glands, while the median region carries filiform-like papillae. In both birds, the papillary crest is located between the body and root. In the kestrel, there is an additional row of papillae rostral to crest, while in the owl there is a rostral lateral extension of papillae on the lateral lingual surface so the distribution pattern has a W-shape. In the kestrel, the posterior part of lingual body has several openings of glands, while the root lacks glands completely, although it has many taste buds. In the owl, the lingual root is folded and has a large number of gland openings. In the kestrel caudally to the glottis, there are two paramedian transverse rows of pharyngeal papillae with a pair of median huge papillae, while in the owl, there is only one transverse row of papillae. The dorsal and ventral lingual surfaces of both birds are lined with non-keratinized stratified squamous epithelium.

A spinal osteoblastoma in a child, situated in the vertebral body – CT and MR imaging

Objective - To report a rare case of a lumbar spinal osteoblastoma involving only the vertebral body. Case report - A 10-year-old boy presented with low back and leg pain, difficulty walking, limping with his right leg, discreet scoliosis on the left side, and lumbar paraspinal muscle spasms. The Lasegue sign for both sides was positive at around 45 degrees. Babinski's sign and sensory changes were not noted. The boy was evaluated by X-ray, computed tomography (CT) and magnetic resonance imaging (MRI) of the lumbosacral spine. CT and MRI scans revealed an expansile lesion that involved the posterior part of the L4 vertebral body, sparing the posterior osseus elements of the L4 vertebra. The lesion extended into the spinal canal, with compression of the thecal sac and the left L5 nerve root. MR images showed osseus edema of the remainder of the L4 vertebral body, enhanced homogeneously. Peritumoral edema extended into the epidural soft-tissue. Total removal of the tumor was performed. The histopathological finding was an aggressive osteoblastoma. Conclusion - Spinal osteoblastomas are extremely rarely situated in the vertebral body alone. CT and MRI are very important methods for delineation of the location, osseous involvement, peritumoral edema and spread of the tumor in the epidural space, with the possible compression by the tumor of the neural elements of the vertebral canal. Total removal of the osteoblastoma is very important because some osteoblastomas may be aggressive, with a tendency to local recurrence and sometimes metastasis.

Description of a new species of Tomiyamichthys from Australia with a discussion of the generic name.

Tomiyamichthys levisquama is described as a new species from the Northern Territory and Queensland, Australia from estuaries and soft bottom marine environments. It is distinctive in body and head shape, head coloration and by the absence of ctenoid scales on the body. It is compared with the related species Tomiyamichthys russus (Cantor 1849), which has ctenoid scales on the posterior part of the body. The validity of the name Tomiyamichthys over Flabelligobius is discussed, with both genera being described in the same paper, here accepting Tomiyamichthys as the appropriate name.

Large thoracic extradural schwannoma atypically invading T2 vertebra

A 53-year-old woman presented with a complaint of back pain. Her medical history and physical examination were unremarkable. Magnetic resonance imaging of the thoracic spine showed a large extradural mass on the right side at the T2– T3 levels (Fig. 1). The lesion widened the right neural foramen and had a large extraspinal component with extension into the posterior mediastinum. The lesion invaded the posterior and right posterolateral parts of the T2 vertebral body (Fig. 2). It was heterogeneously hypointense to muscles on T1weighted, and hyperintense on T2-weighted images. Postcontrast images showed intense enhancement of the lesion. The tumor was resected, and T2 corpectomy was also performed. Histopathologic examination revealed the diagnosis of schwannoma without malignant transformation. Schwannoma is the most common spinal nerve sheath tumor, which is followed by neurofibroma and ganglioneuroma. Invasion and osteolytic expansion of the vertebral body by schwannoma is extremely rare. Schwannoma should be included in the differential diagnosis of large extradural lesion causing invasion and destruction of the spine, especially if it shows typical imaging findings such as neural foraminal widening and adjacent bony remodeling [1].