Orbital Margin Research Articles

Morphometric Analysis of the Infraorbital Foramen: The Clinical Relevance.

The present study was conducted to ascertain the shape, size, presence of accessory foramina, direction, and the precise position of the infraorbital foramen (IOF) in relation to the inferior orbital margin (IOM), anterior nasal spine (ANS), nasion (Na), maxillary teeth, and supraorbital foramen/notch (SOF/N) in adult skulls in a Sri Lankan population. Fifty-four skulls (42 males and 12 females) were analyzed. The IOF was oval in shape (38.6% and 36.3% on the right and left side, resp.) in a majority of skulls. The direction of the IOF was mostly medially downward (48.6%). Accessory foramina were found in 7.4% of the skulls. The infraorbital foramina were located at a mean distance of 6.52 ± 2.03 mm and 7.30 ± 1.57 mm, vertically below the IOM on the right and left side, respectively; 33.81 ± 2.68 mm and 34.23 ± 2.56 mm from the ANS on the right and left side, respectively; and 42.37 ± 3.52 mm and 42.52 ± 3.28 mm from the Na on the right and left side, respectively. In relation to the upper teeth the majority of IOF (37.5% and 55.9% on the right and left side, resp.) were located in the same vertical axis as the tip of the buccal cusp of the maxillary second premolar tooth.

Location and incidence of the zygomatico-facial foramen in dry human skulls: An anatomical study

IntroductionZygomaticofacial foramen (ZFF) is present on the lateral surface of zygomatic bone. Zygomaticofacial nerve passes through it. The knowledge of incidence and location of ZFF has surgical importance. Materials and methodsSeventy dry human skulls of indeterminate age and gender were studied for location, incidence and variations pertaining to zygomaticofacial foramen (ZFF). Region-wise incidence of ZFF was noted by dividing the lateral surface of zygoma into four (A, B, C & D) regions. The frequency of number of foramina was noted. The distance of ZFF from the orbital margin, frontozygomatic suture and zygomaticomaxillary suture were measured. ResultsLocation wise the incidence of the ZFF was more in the ‘C’ region with frequency of 51.82% followed by 25.54% and 22.62% in ‘A’ & ‘B’ regions respectively with none in ‘D’ region. The number of foramina varied from absent to maximum of three. The single foramen was found in 67.14% of skulls. Frequency of absence of foramen was 18.57%. In 12.14% of skulls two foramina were observed whereas three foramina were seen in only 2.14% of skulls. The mean distances of the ZFF from frontozygomatic suture (FZ), zygomaticomaxillary suture (ZMS) and orbital margin in ‘mm’ is 27.4 & 27.29, 20.05 & 19.88 and 8.05 & 7.82 on the right and left side respectively. DiscussionThe study shows variability in the location and incidence of the ZFF which makes it a less reliable landmark for reference during surgical procedures in the region.

A Pliocene mekosuchine (Eusuchia: Crocodilia) from the Lake Eyre Basin of South Australia

ABSTRACTA new genus and species of crocodilian, Kalthifrons aurivellensis, is described from a channel sand deposit incised into the Oligo-Miocene Etadunna Formation on the western shore of Lake Palankarinna in the Lake Eyre Basin, South Australia. The channel sand is interpreted as an outcrop of the Mampuwordu Sand Member of the Tirari Formation, which has been assigned an early Pliocene age. The taxon can be diagnosed by the extremely elongate and narrow anterior process of the frontal pair and a distinctively beveled and laterally expanded prefrontal contribution to the orbit margin. The broadly triangular rostrum, at least partially interlocking dentition, smooth dental carinae, and weak labiolingual compression resemble unspecialized crocodilian species, and it was probably a generalist aquatic predator. It possessed character states that indicate that it was not a member of Crocodylus, and it is referred to the endemic Australasian clade Mekosuchinae. The first overlying unit in the Lake Eyre Basin sequence to produce diagnostic crocodilian remains is the mid- to late Pliocene Pompapillina Member of the Tirari Formation. It contains a true species of Crocodylus but no indication of Kalthifrons aurivellensis or indeed any other mekosuchine, indicating that the latter may have been driven to extinction via competitive replacement.http://zoobank.org/urn:lsid:zoobank.org:pub:C4E93358-D80F-4E4D-B7FF-BFFB93EDCD54SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVPCitation for this article: Yates, A. M., and N. S. Pledge. 2016. A Pliocene mekosuchine (Eusuchia: Crocodilia) from the Lake Eyre Basin of South Australia. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2017.1244540.

Management of Zygomatic Fractures in Young Patients: Technical Modifications for Aesthetic and Functional Results.

The zygomaticomaxillary complex is very vulnerable to injury because of its intrinsically prominent convexity. There are 2 different surgical approaches for the therapy of these fractures: closed reduction and open reduction. In the open reduction 2 or 3 fixation points with related incisions are usually necessary in dislocated fractures: osteosynthesis must be performed starting from zygomaticofrontal suture when dislocated at this site, followed by zygomatic body fixation on the anterior sinus wall, anterior orbital floor margin fixation, and finally orbital floor reconstruction in case of eye globe dislocation with diplopia. This study evaluated the combination of the transconjunctival (TC) approach without canthotomy in association with the transoral maxillary approach and lateral rim skin incision (SI) without canthotomy for frontozygomatic dislocated fractures to achieve proper reduction and stabilization without any aesthetic decay in young patients. A less invasive and more aesthetic technique is shown for treating dislocated zygomaticomaxillary complex fractures with 2 or 3 fixation points and platelet-rich fibrin (PRF) use to promote tissue healing. Ten patients (mean age: 32) were referred for dislocated zygomaticomaxillary complex fracture. Five patients were treated by TC approach without canthotomy in association with the transoral maxillary approach and, when needed, eyebrow SI without canthotomy for frontozygomatic dislocated fractures (group 1). Five more patients were treated by traditional subciliar incision at lower eyelid and vertical lateral incision at lateral margin of the orbit (group 2). Autologous PRF for orbital floor reconstruction was used. The follow-up period was 6 months long. Follow-up radiographs (TC) and photos were routinely used to evaluate the adequacy of reduction and lower eyelid right position or retraction. All cases were successful; there were no problems at surgery and postoperative time. During the 6-month follow-up, all 5 patients of group 1 showed satisfactory facial symmetry, no noticeable scarring, no ectropion or lower eyelid significant droop, and no functional impairment. Mean difference for lower eyelid droop between the 2 groups of patients was 1.4 mm at T1 and 1.2 mm at T2. Aesthetic result is a priority in the treatment planning of orbitozygomatic fractures because of the fundamental role of the eye and lid area in the aesthetic of the face. In our experience best aesthetic results were achieved through a latero cantal horizontal SI combined to a vertical periosteal incision at the frontozygomatic rim without canthotomy, thus performing a different double-layer incision. In the patients with large orbital floor dislocation, reconstructive titanium mesh was covered by autologous PRF membranes, which can improve the vascularization of the surgical site, by promoting neoangiogenesis. In young patients these techniques are indicated because of the need of better aesthetic results that can be achieved by preventing postoperative functional impairment with lower eyelid droop and unnatural aesthetic asymmetry of the 2 lower lids. This more conservative technique resulted in better aesthetic results, avoiding most common complications.

Positional Relationship of Ethmoidal Foramens With Reference to the Nasion and Its Significance in Orbital Surgery.

The aim of the study was to elucidate the positional relationship of the ethmoidal foramens (EFs) with reference to the nasion to facilitate prediction of the exact location of EFs, the optic canal (OC), and the frontoethmoidal suture (FS), and thereby avoid complications during complex surgery involving the medial wall of the orbit. One hundred two intact orbits of 57 embalmed cadavers were dissected in this observational anatomic study. Nasion' (N') was defined as the intersection point of the medial orbit margin with the horizontal line through the nasion, and this was used as a reference point. N'-OC was defined as the straight line joining N' and OC. The locations of the anterior ethmoidal foramen (AEF), posterior ethmoidal foramen (PEF), and OC were determined with reference to N'. The vertical distances from N'-OC to EFs and to FS were also determined. The N'-AEF, AEF-PEF, and PEF-OC distances were 18.4, 15.3, and 8.3 mm, respectively. Vertically, AEF and PEF were situated at 0.2 mm below and 0.4 mm above N'-OC, respectively. At the same reference points, N'-OC was situated at 0.4 and 0.6 mm above FS, respectively. N', AEF, PEF, and OC were considered to be situated on the same straight line, and N'-OC could be regarded as coinciding with FS. This means that N' is an easily identifiable and reliable landmark for identifying EFs, OC, and FS. Our navigational parameters with reference to N' will help surgeons to enhance the safety of orbital surgery.

Biomechanics analysis of the impact of maxillofacial injury on skull base damage

To analyze the impact of maxillofacial injury on skull base. A three-dimensional(3D)finite-element model of cranio-maxillofacial bone was established by CT scan data. A lead cylinder in base diameter of 3 cm was designed as an impactor. There regions(upper right maxilla, left infraorbital margin and left zygomatic body)subjected to an impact at the speed of 8.6 m/s(about 30 km/h)was simulated. Thirteen landmarks at the skull base were selected. The values of stress at the end of 0.5, 1.0, 1.5, 2.0 ms were obtained, and the results were analyzed. The dynamic process of the fracture of the jaw and the stress distribution and conduction of the skull base were successfully simulated in three parts of the face. When the impact was on the right maxillary bone region, the stress values of the three points(medial foramen rotundum, medial foramen rotundum, anterior clivus reached the peak at each time point, 26.2, 22.4, 21.5 MPa(t=0.5 ms)and 70.0, 55.0, 45.0 MPa(t=1.0 ms)and 38.0, 26.5, 39.5 MPa(t=1.5 ms)and 26.0, 19.0, 23.0 MPa(t=2.0 ms), respectively. When the impact was on the left margo infraorbitalis orbitaeta region, the stress values of the two points(medial left foramen rotundum, posterior clivus)reached the peak at each time point, 8.8, 16.0 MPa(t=0.5 ms)and 10.0, 18.0 MPa(t=1.0 ms)and 5.5, 6.0 MPa(t=1.5 ms)and 11.5, 12.5 MPa(t=2.0 ms), respectively. When the impact was on the body of left zygomatic bone, the stress values of posterior clivus were 45.0 MPa(t=0.5 ms), 40.0 MPa(t=1.0 ms), 12.0 MPa(t=1.5 ms), 42.5 MPa(t= 2.0 ms), respectively. According to the difference of stress distribution and conduction of maxillofacial and skull base bone, the speed and the path of force transfer to the skull base were different. Finite-element dynamic simulation can be used for the biomechanics research on maxillofacial trauma.

Motor Innervation of the Corrugator Supercilii Muscle in Relation to Orbital Landmarks: Guidelines for Surgical Denervation.

Precise knowledge of the nerve supply of the corrugator supercilii muscle (CSM) is a prerequisite for performing a selective denervation of the CSM. The authors' goal was to determine the course and variability of the motor nerves of the CSM in relation to fixed orbital landmarks. The facial nerve branches toward the CSM were identified during microscopic dissection of 9 Caucasian formaldehyde-fixed cadaver half-heads. The distances between the branches and defined landmarks were measured. All branches to the transverse head of the CSM ran between 15 and 32 mm superior to the lateral orbital margin. Medially the CSM was supplied by a superficial zygomatic, buccal, or bucco-zygomatic branch, which was much smaller than the temporal branches. This branch ran 4 to 7 mm medial to the medial canthus. This anatomical knowledge can be applied for surgical denervation of the corrugator supercilii muscle. The authors suggest a surgical procedure for corrugator denervation through a blepharoplasty incision.

Clinical observation on the improved reductive surgery for the treatment of zygomatic complex fractures

Objective To observe the clinical effect of improved reductive surgery for zygomatic complex fracture. Methods Thirty-two patients with zygomatic complex fractures were given zygomatic arch and lateral orbital wall fracture CT 3D reconstruction before operation to display position of fracture. The skin incision was made along the lower eyelid margin and extended about 15 mm outward canthus. Then the periosteotomy was done and the periosteum was separated to the back of zygomatic arch. The fracture was fixed with micro titanium nail plate to restore the normal anatomical position of zygomatic arch and to reset orbital margin completely. Results Two weeks after the operation, the soft tissue swelling of the orbital region faded. The deformity was completely corrected, and the opening movement of mouth was improved obviously compared with that before the operation. Three months after the surgery, the zygomatic appearance was symmetrical in 32 cases, with no obvious differences in appearance. Mouth opening degree was higher than 40 mm.The two eyeballs were symmetrical. Conclusion The improved subciliary approach combined with micro titanium nail and plate for zygomatic complex fracture has good effect. Key words: Fractures, traumatic; Zygomatic complex; Reductive surgery, modified; Incision

Olfactory Neuroblastoma

This 57 year-old woman presented with a seizure. She had a history of attending the ENT and neurosurgical departments for more than a decade. At the time of her initial presentation many years prior, her main complaint was of nasal congestion. A nasopharyngeal biopsy confirmed an olfactory neuroblastoma.
 
 Olfactory neuroblastoma is an uncommon slow growing tumour of the nasal cavity with no established etiological basis. With a neuroectodermal origin, it arises from the olfactory epithelium of the upper nasal cavity.1 Most cases arise from the cribriform plate, upper third of the nasal septum, superior turbinates or anterior ethmoidal air cells. However, it typically presents late when multiple structures are involved, which may include the orbits and intracranial compartments.2
 
 Accounting for approximately 2% of sinonasal tumors, although often late to present, ironically only a minority of patients experience anosmia.3 The commonest complaint at initial presentation is nasal blockage accounting for nearly a quarter of cases, with headache and epistaxis the next most frequent symptoms.1
 
 Multi-modality imaging is essential in that the most recognized management of this infrequent tumor is a combination of craniofacial surgery and radiotherapy. The imaging pathway in this case was typical, with CT and MRI complementing each other in maximizing tumor delineation. Computed Tomography has superior definition is reviewing bony involvement which is a typical finding, whereas MRI has superiority in evaluating the extent of soft tissue invasion and establishing tumor boundaries against post obstruction fluid in the paranasal sinuses.3 In this case the CT illustrates the gross destruction of the skull base, orbital and sinus margins. (Figure 1-4) The MRI outlines the extension of disease involving the pituitary fossa, brainstem and frontal sinus invasion. (Figures 5 and 6)
 

Skull osteology of the Eocene amphisbaenian Spathorhynchus fossorium (Reptilia, Squamata) suggests convergent evolution and reversals of fossorial adaptations in worm lizards.

The fossorial amphisbaenians, or worm lizards, are characterized by a suite of specialized characters in the skull and postcranium, however fossil evidence suggests that at least some of these shared derived traits evolved convergently. Unfortunately the lack of detailed knowledge of many fossil taxa has rendered a more precise interpretation difficult. Here we describe the cranial anatomy of the oldest-known well-preserved amphisbaenian, Spathorhynchus fossorium, from the Eocene Green River Formation, Wyoming, USA, using high-resolution X-ray computed tomography (HRXCT). This taxon possesses one of the most strongly reinforced crania known among amphisbaenians, with many dermal bones overlapping each other internally. In contrast to modern taxa, S.fossorium has a paired orbitosphenoid, lacks a true compound bone in the mandible, and possesses a fully enclosed orbital rim. The last feature represents a highly derived structure in that the jugal establishes contact with the frontal internally, reinforcing the posterior orbital margin. S.fossorium also possesses a strongly modified Vidian canal with a previously unknown connection to the ventral surface of the parabasisphenoid. Comparison with the closely related fossil taxon Dyticonastis rensbergeri reveals that these derived traits are also shared by the latter species and potentially represent synapopmorphies of an extinct Paleogene clade of amphisbaenians. The presence of a reinforced orbital rim suggests selection against the loss of a functional eye and indicates an ecology potentially different from modern taxa. Given the currently accepted phylogenetic position of Spathorhynchus and Dyticonastis, we predict that supposedly 'unique' cranial traits traditionally linked to fossoriality such as a fused orbitosphenoid and the reduction of the eye show a more complex character history than previously assumed, including both parallel evolution and reversals to superficially primitive conditions.

Electrode montage and gaze effects on ocular vestibular evoked myogenic potentials (oVEMPs).

To investigate the properties of lateral electrode locations compared to the conventional ones and to bipolar compared to chin-referenced montages for recording ocular vestibular evoked myogenic potentials (oVEMPs). A total of 18 subjects were studied using 5 electrode locations around the eye, including the conventional location and more lateral ones (i.e. M, ML and L electrodes near the orbital margin, R1 and R2 electrodes below the two more medial ones). Unilateral air-conducted (AC) sound, bone-conducted (BC) impulses at the mastoid and BC vibration (500Hz) at the forehead were used. These were applied while the subjects looked in neutral gaze and with 4 levels of increasing elevation. A subset of 10 subjects were also studied when looking downwards at 4 levels. Five bipolar montages were created offline by subtraction. The M and ML electrodes had the largest responses but responses were seen for all 5 electrodes. The chin reference was associated with substantial pickup from the contralateral side (as judged using unilateral AC stimulation). The M-R1 (conventional) montage showed a significantly non-linear response to gaze angle, unlike the ML montages. The ML-R1 montage gave the largest responses. There was a clear change in latency for the conventional montage with downgaze for the AC and BC impulsive stimuli. The ML active electrode has a more stable n1 latency, a larger and a more linear response to gaze angle than the conventional recording site, probably due to contamination by pickup of inferior rectus activity when using the conventional site. The ML location is a better site for the active pickup for recording oVEMPs if the main object of study is the inferior oblique muscle and particularly if subjects have difficulty with upgaze.

A new reptile from the Richards Spur locality, Oklahoma, U.S.A., and patterns of Early Permian parareptile diversification

ABSTRACTThe Lower Permian Richards Spur locality is the most speciose Paleozoic continental vertebrate assemblage currently known, and a significant proportion of the tetrapod diversity found at the locality is made up of parareptiles. The first Richards Spur parareptile to be described was Colobomycter pholeter. It has been characterized by its enlarged premaxillary tooth and paired enlarged maxillary teeth, unique dentition that grants it an appearance quite distinct from other parareptiles at Richards Spur. Here we describe new cranial material from Richards Spur that is referable to Colobomycter. This new material differs from that of C. pholeter in that it possesses at least three more teeth on its maxilla, the enlarged premaxillary and maxillary teeth are more gracile than those in C. pholeter, and the lacrimal is restricted externally to the orbital margin and does not exhibit an extra lateral exposure. We infer that these differences merit specific distinction and assign the new fossil to Colobomycter vaughni, sp. nov. The discovery of C. vaughni at Richards Spur is important, because it reveals the presence of another member of the clade Lanthanosuchoidea in Oklahoma, making it the sixth to be found in the state. The large number of taxa from this clade found in Oklahoma suggests that during the Early Permian, this area of western Laurasia was the center of a radiation of small, predatory lanthanosuchoids.http://zoobank.org/urn:lsid:zoobank.org:pub:149450CF-4CB8-4099-B037-7E371A5AB286SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVPCitation for this article: MacDougall, M. J., S. P. Modesto, and R. R. Reisz. 2016. A new reptile from the Richards Spur locality, Oklahoma, U.S.A., and patterns of Early Permian parareptile diversification. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2016.1179641.

Anthropometric Analysis of Infraorbital Foramen in Adult Indian Dry Skull

Abstract Introduction: Normally infra orbital foramen (IOF) is situated on the anterior surface of maxilla about 1cm below the infra orbital margin (IOM) bilaterally. Infra orbital vessels and nerves emerge out through this foramen. Infra orbital nerve (ION) terminates by supplying skin over the lower eyelid, conjunctiva, lateral aspect of external surface of nose, upper lip, ala of the nose and the premolar teeth. Infra orbital vessels supply the area surrounding the IOF. Objective: To measure distance between superior part of the rim of the IOF to IOM (DIM) and the distance between the medial part of the rim of the IOF to lateral margin of the pyriform aperture (DIP). Compare the measurements of both sides. Compare our studies with other authors. Materials and methods: Sixty adult dry skulls of unknown sex were studied. Those skulls with damaged foramen were excluded. Measurements were done in millimetres. Result: The mean DIM on right side is 5.96 mm and on left side it is 6.07. Mean DIP on right side is 16.70 mm and on left side it is 16.63mm. We have observed that there is no much significant variations in respect to sides. Our values were within the range of many others value. Conclusion: Knowing exact location of IOF using different land mark is important for providing local anaesthesia in maxillofacial, plastic surgical operations and radio ablative neurotomy procedures. Thus information obtained is very useful IOF to avoid iatrogenic injury in the infra orbital area.

Anatomical Study of the Intraosseous Pathway of the Infraorbital Nerve.

The infraorbital nerve (ION) is at risk for iatrogenic injury during orbital floor repair. The authors aim to anatomically characterize the intraosseous course of the ION between the inferior orbital fissure and infraorbital foramen. Ten cadaver heads (20 orbits) were dissected, with exposure of the orbital floor. The ION was identified from the infraorbital fissure to inferior orbital foramen. The presence and caliber of an osseous roof was noted. Distances measured were infraorbital foramen to infraorbital margin; length of the inferior orbital groove; length of the inferior orbital canal; length from the inferior orbital fissure to the infraorbital margin. Three variations of the osseous anatomy around the ION were identified. Four cadavers had no identifiable groove (Type 1, 40%) and the ION was completely roofed throughout its course. Five specimens exhibited a thin, transparent osseous roof over the nerve before forming the true canal, which we describe as a "pseudocanal" (Type 2, 50%). A true groove was seen in both orbits from a single cadaver (Type 3, 10%). Each cadaver had an ION course of the same type on both sides. Mean ± SD intraorbital foramen to infraorbital margin distance was 7.1 ± 1.4 mm. Distance from the infraorbital fissure to the infraorbital margin was 28.5 ± 2.3 mm. The course of the infraorbital nerve can be described as Type 1 (true canal), Type 2 (pseudocanal), and Type 3 (groove and canal). The authors propose that this novel classification system will raise awareness of variations in orbital floor anatomy.

Zygomatic fractures: Technical modifications for better aesthetic and functional results in older patients

IntroductionThe zygomaticomaxillary complex, with its intrinsically prominent convexity, is highly vulnerable to injury. In this study, we evaluated a novel combined approach to the reduction and stabilization of frontozygomatic dislocated fractures without aesthetic damage. Materials and MethodsTen patients (mean age, 52 years) were referred for complex frontozygomatic dislocated fractures. Five patients underwent a transconjunctival approach without canthotomy in association with a transoral maxillary approach and lateral-rim skin incision, also without canthotomy. The other five patients underwent a traditional subciliary incision at the lower eyelid and a vertical lateral incision at the lateral orbital margin. Orbital floor reconstruction was achieved using two to three fixation points and autologous platelet-rich fibrin (PRF). During the 6-month follow-up, the patients were routinely evaluated using computed tomography. ResultsTreatment was successful in all cases; there were no problems at surgery or postoperatively. During follow-up, all patients had satisfactory facial symmetry, no noticeable scar, ectropion, or lower-eyelid drop, and no functional impairment. DiscussionAesthetic considerations are an important aspect of treatment planning in patients with orbitozygomatic fractures, because of the importance of the eye and lid areas to facial aesthetics. In our patients, good aesthetic results were achieved using a novel combined approach. In patients with a large orbital floor dislocation, the reconstructive titanium mesh can be covered by autologous PRF membranes to improve vascularization of the surgical site. By preventing aesthetic damage and functional impairment, our conservative approach is of particular utility in older individuals due to age-related tissue laxity.

Location of the infraorbital foramen with reference to soft tissue landmarks.

The location of the infraorbital foramen and its variations are important during periorbital, dental, plastic, and oromaxillofacial surgeries. The aim of this study is to document the most practical anatomical soft tissue landmarks for defining the location of infraorbital foramen and infraorbital nerve for effective nerve blockade and to decrease its risk of injury during periorbital surgeries. Forty sides from 20 adult fixed cadavers were used for this study. The position of the infraorbital nerve was determined in reference to the lateral edge of the ala of the nose, medial and lateral palpebral commissures. All these three soft tissue landmarks were then connected to each other forming a triangular shaped region. In 75% of the cases the infraorbital foramen was located on the line which is connecting the lateral palpebral commissure to the ala of the nose. The closest distance of infraorbital foramen to the inferior orbital margin and to facial midline was also measured. The infraorbital foramen was located outside the previously defined triangular region in 20% and inside the triangle in 5%. The closest mean distance between the infraorbital foramen and the infraorbital margin was measured as 8.8±1.0mm and the distance between the medial wall of the infraorbital foramen and the facial midline was measured as 30.3±2.7mm. The triangular region and the soft tissue landmarks we offered in this study may facilitate prediction of the locations of the infraorbital foramen thus, the infraorbital nerve.

Yuanansuchus maopingchangensis sp. nov., the second capitosauroid temnospondyl from the Middle Triassic Badong Formation of Yuanan, Hubei, China.

A second species of Yuanansuchus, Y. maopingchangensis, is erected for new temnospondyl material from the Maopingchang site, Yuanan County, Hubei Province, China. These specimens are from the same horizon that produced Y. laticeps, the type species. Y. maopingchangensis shares the following features with Y. laticeps: postorbital portion of skull occupied more than 1/3 of skull length; tabular horn directed laterally; lateral line sulci continuous, well impressed; supraorbital sensory canal enters lacrimal; preorbital projection of jugal less than half length of snout; and vomerine plate short. However, Y. maopingchangensis differs from Y. laticeps in having an elongated skull, frontal extending posteriorly to the level of the posterior orbital margin, closed otic fenestra, cultriform process of parasphenoid extending to the level of the anterior margin of the interpterygoid vacuities, and absence of fodina vomeralis. Analysis of a new capitosaur phylogenetic data matrix, containing 56 characters and 29 species, confirms that the two species from Yuanan are sister taxa and that Capitosauroidea can be divided into two major clades: one including Parotosuchus, Eryosuchus, Calmasuchus and Cherninia, and another including Mastodonsaurus, Yuanansuchus, Stanocephalosaurus, Procyclotosaurus, Paracyclotosaurus, Antarctosuchus, Eocyclotosaurus, Quasicyclotosaurus, Tatrasuchus and Cyclotosaurus.

A new species of <i>Cyclotosaurus</i> (Stereospondyli, Capitosauria) from the Late Triassic of Bielefeld, NW Germany, and the intrarelationships of the genus

Abstract. A nearly complete dermal skull roof of a capitosaur stereospondyl with closed otic fenestrae from the middle Carnian Stuttgart Formation (Late Triassic) of Bielefeld-Sieker (NW Germany) is described. The specimen is assigned to the genus Cyclotosaurus based on the limited contribution of the frontal to the orbital margin via narrow lateral processes. A new species, Cyclotosaurus buechneri sp. nov., is erected based upon the following unique combination of characters: (1) the interorbital distance is short so that the orbitae are medially placed (shared with C. robustus); (2) the region lateral to the orbitae is only slightly broader than the orbitae (shared with C. posthumus, C. ebrachensis, C. intermedius, and C. mordax); (3) the postorbital region is slender (shared with C. ebrachensis); (4) the preorbital projection of the jugal is shorter than half the length of the snout (shared with C. mordax, C. ebrachensis, C. intermedius, C. posthumus, and C. hemprichi). A phylogenetic analysis of seven Cyclotosaurus species, including C. buechneri, and eight further capitosaur taxa with the Rhinesuchidae as an outgroup finds a monophyletic Cyclotosaurus. In accordance with its stratigraphic occurrence, C. buechneri nests at its base but is more derived than C. robustus. Among the more derived Cyclotosaurus species, C. ebrachensis and C. intermedius, as well as C. posthumus and C. hemprichi, form sister groups, respectively. However, the phylogenetic position of C. mordax with respect to both groups remains unresolved. In the phylogenetic analysis presented here, Cyclotosaurus is the sister group of the Heylerosaurinae (Eocyclotosaurus + Quasicyclotosaurus). Cyclotosaurus buechneri represents the only unequivocal evidence of Cyclotosaurus (and of a cyclotosaur in general) in northern Germany.

An Investigation on the Population Structure of Green Tiger Shrimp Penaeus semisulcatus (De Hann, 1844) of Kerala Coast

The present investigation was carried out to detect the variation in the morphometric characters and also by the biochemical methods (protein and enzyme profile) of Penaeus semisulcatus . A set of four morphometric variables, the depth of the abdomen (SSD) at the mid-point of the sixth segment; depth of the abdomen (SAD) at the intersection of the second and third segments, partial carapace length (PCL) from the posterior margin of the orbit to the posterior edge of the carapace; width of the carapace (CW) at the point of the last dorsal rostral tooth were measured. Among the four variables measured sixth segment depth (SSD) showed the highest correlation with the tail weight (TLW). Considerable differences are not seen, indicating the samples collected from Kochi and Calicut belongs to a single morphological stock .Biochemical analysis of protein and enzymes - Aldehyde oxidase (AO), Aldolase (FBALD), Octanol dehydrogenase (ODH), and Esterase (EST) by Polyacrylamide Gel Electrophoresis (PAGE) was conducted on P. semisulcatus collected from selected landing centres such as Kochi and Calicut of west coast of Kerala. Considerable differences in banding patterns were not found in the stocks obtained from Calicut and Kochi and can be related to the fact that the genetic makeup is similar (Homozygous).

“Evaluation and comparison of alveolar bone loss of maxilla and mandible in completely edentulous patients on digital panoramic radiographs”

Aim: Evaluation and comparison of alveolar bone loss of maxilla and mandible in completely edentulous patients on digital panoramic radiographs. Methods: Alveolar bone loss was evaluated on digital panoramic radiograph. In maxilla, alveolar bone height was evaluated by a horizontal line joining both inferior margins of the infraorbital margin (Lz) was drawn. The midline was determined by vertical line joining the Lz to the nasal septum. Another vertical line joining from premolar region and molar region represented vertical distances from line Lz to the alveolar crest. In the mandible, a line was drawn tangential to the most inferior points at angle of mandible and the lower border of the mandible. The measurement of the midline to alveolar crest, for premolar and molar region the line vertically drawn at the mental foramen region for premolar region and another vertical line drawn from the molar region to alveolar crest. Results: The mandible showed significant bone loss (p