Virtual microscopy as a teaching-learning tool for histology in a competency-based medical curriculum.

Background: Histology forms an important component of first-year medical education. Unfortunately, it is limited to the practical laboratory due to the need for a microscope and good quality slides. Virtual microscopy is a recent advancement, which uses computers as an alternative to microscopes. The aim of the study was to compare virtual microscopy (VM)-based practical classes with traditional microscopy (TM)-based practical classes for two cohorts of first-year medical students, by comparing learning achieved using two different test scores as well as a qualitative assessment of student and faculty perspectives regarding the feasibility and usefulness of VM. Methods: Each cohort of students was divided into two equal batches and each batch underwent eight histology modules of which, four utilised traditional microscopes and four utilised virtual microscopes. Quantitative analysis was performed using a theory test (which assessed preparation, theory knowledge and understanding) as well as a spotter test (which assessed identification skills, reasoning, and recall). Qualitative analysis was performed using a structured questionnaire and focus group discussions. Results: Modules using VM were better when compared with those using TM, showing statistically significant and better grades. Qualitative analysis performed, yielded important information as to how this technology can serve as a good adjunct to traditional histology classes in the competency-based curriculum by increasing student interest, enabling self-study, and reducing students dependence on the tutor. Conclusions: VM forms a good adjunct as well as a standalone modality of learning to TM, as it improves accessibility to slides and promotes self-learning.

Immunolocalization of CD1a expressing dendritic cells in sinonasal polyposis.

Sinonasal polyps are benign projections of edematous nasal mucosa lined by respiratory epithelium. Langerhans cells (LCs) belonging to the dendritic cell family located in respiratory epithelium are involved in antigen presentation and maintenance of local immunological homeostasis. This study aims to elucidate the morphology and distribution of CD1a positive LCs in normal nasal mucosa and compare the same with polypoid nasal mucosa by immunohistochemistry. Normal nasal mucosa (n = 20) was obtained from patients who underwent septoplasty for deviated nasal septum. Polypoid nasal mucosa (n = 22) was obtained from patients with chronic rhinosinusitis (CRS) or allergic fungal rhinosinusitis who underwent excision of nasal polyps. The tissues obtained were processed for immunohistochemistry and stained with CD1a-EP80 Rabbit monoclonal antibody. In the tissues studied, CD1a positive LCs were observed in both the epithelium and lamina propria. Different morphological subtypes of LCs were noted in the epithelium. The cells were distributed adjacent to walls of subepithelial capillaries and cysts. The median number of CD1a positive LCs was significantly higher in polypoid category (13.5 per mm2) as compared with normal nasal mucosa (2.5per mm2) (p = .001). Presence of CD1a positive LCs in polypoid nasal mucosa hints at a critical immunological role in the etiopathogenesis of nasal polyps.

Emergency remote learning in anatomy during the COVID-19 pandemic: A study evaluating academic factors contributing to anxiety among first year medical students.

BACKGROUND: 'Emergency remote learning' (ERL) has been undertaken as an emergency response globally to facilitate online shift of medical education due to COVID-19. Although medical students world-wide have reported an increased level of anxiety, factors in the academic setting during ERL that influenced anxiety levels have not been studied yet. The present study aimed to evaluate anxiety levels of first year medical students and its correlation with academic factors during ERL. METHODS: ERL for neuroanatomy was conducted for six weeks mainly by online small group teaching. At completion, feedback was collected from students (n = 97) which included a GAD-7 questionnaire for anxiety levels and a modified VARK analysis to record changes in learning styles. RESULTS: Of 97 students (M46, F51) 43.30% had minimal, 31.96% mild, 10.31% moderate and 14.43% severe anxiety. Academic exchanges such as student-teacher interaction (80.41%), tutor feedback (90.72%) and mentor meetings (81.44%) were reported to be advantageous. There was a significant (p = 0.0056) correlation between enjoyment of small group discussion and lower GAD-7 scores. There was significant change in perceived learning styles during ERL. Video calls (p = 0.018) and gaming (p = 0.022) were significant modes of stress relief. There was significant correlation (p = 0.022) between gaming and GAD-7 scores. CONCLUSION: About one-fourth of the students faced anxiety issues during ERL period. Small group interactions with focus on promoting connectedness and interaction, augmented by feedback, mentorship, familial and social support are important in reducing anxiety which should be kept in mind by educators while delivering such learning experiences.

Structured, functional histology practical modules: An answer to medical students' histology nightmare and the way forward for relevant histology instruction in the Indian undergraduate medical curriculum?

Background: . It is often a challenge to make histology instruction relevant and interesting. We assessed whether structured, worksheet-based histology practical modules with emphasis on functional histology and clinical application, would improve the learning experience and help students focus on relevant functional and clinical correlates. Methods: . In eight practical sessions, 100 students worked as two groups, one group undergoing new intervention practical modules and another group undergoing the routine laboratory practical exercises as a control group. For every pair of laboratory practical exercises, the groups alternated. Spot tests administered in the following week assessed identification ability as well as application of knowledge. Feedback was collected in the form of written questionnaires from faculty and students, student focus group discussion and in-depth interviews. Analysis of test scores as well as feedback was done. Results: . Test scores were better following the intervention method when comparing the overall score as well as its subcomponents of identification and analysis-type questions (p<0.001). The weaker performers in the class as well as high achievers showed better test scores with the intervention method (p<0.001). Feedback from faculty and students reflected better student experience with the intervention method. Suggestions were made to improve the approach further. Conclusion: . Studying histology through structured modules, which emphasize functional and clinical correlates, appears to improve the identification and application ability of the student as well as the student experience.

Comparison of CT numbers of organs before and after plastination using standard S-10 technique.

Plastination is the art of preserving biological tissues with curable polymers. Imaging with plastinates offers a unique opportunity for radiographic, anatomical, pathological correlation to elucidate complex anatomical relationships. The aim of this study was to make plastinates from cadavers using the standard S-10 plastination technique and to compare the radiological properties of the tissue before and afterwards to examine the suitability of plastinates as phantoms for planning radiotherapy treatment. An above-diaphragm and a below-diaphragm specimen were obtained from a male and a female cadaver, respectively, and subjected to the standard S-10 plastination technique. CT images were obtained before and after plastination and were compared using Treatment Planning System for anatomical accuracy, volume of organs, and CT numbers. The plastinated specimens obtained were dry, robust, and durable. CT imaging of the plastinated specimens showed better anatomical detail of the organs than the preplastinate. Organ volumes were estimated by contouring the organs' outline in the CT images of the preplastinated and postplastinated specimens, revealing an average shrinkage of 25%. CT numbers were higher in the plastinated specimens except in bones and air-filled cavities such as the maxillary air sinus. Although plastination by the standard S-10 technique preserves anatomical accuracy, it increases the CT numbers of the organs because of the density of silicone, making it unsuitable for radiation dosimetry. Further improvements of the technique could yield more suitable plastinated phantoms.

Different subsets of Langerhans cells in human uterine tubes and uterus.

AIM: Langerhans cells (LC) are antigen-presenting cells present in tissues with high antigenic exposure. Their role in the upper female reproductive tract is not fully understood. This study aims to determine the distribution and morphology of LC in the normal and post-partum human uterine tubes and uterus by staining with the specific LC markers, CD1a and zinc iodide-osmium (ZIO), and to determine their association with helper and cytotoxic T cells. MATERIAL AND METHODS: Normal and post-partum uterine tube and uterine specimens were stained with CD1a and ZIO and their morphology and distribution noted. Double immune staining with CD1a-CD4 and CD1a-CD8 in post-partum uterine tube were also done. RESULTS: It was noted that CD1a-positive cells were significantly fewer and smaller in diameter than ZIO-positive cells in the uterine tube and both types of cells were significantly more prevalent in post-partum tubes. Perivascular clusters of ZIO-positive cells were seen in the post-partum tubes. Close association of CD1a-positive cells with CD4- and CD8-positive T cells was noted in the post-partum uterine tube. In the uterus, scanty CD1a-positive cells were present in the surface and glandular epithelium and endometrial stroma. ZIO-positive cells were absent. CONCLUSION: This study suggests that CD1a-positive and ZIO-positive cells may be different subsets of LC that are needed for presentation of antigen to immunocompetent cells. Their respective functions are yet to be determined.

Riedel's Lobe and Beaver Tail Variant: A Cadaveric Case Report.

Variations of the liver in the form of accessory lobes account for about less than 1%. One of the commonest accessory lobes on the right is Riedel's lobe. An occasional anatomical variant of the left lobe is the beaver tail variant. Both variants are reported to be common in females. We hereby report two cases. A 45-year-old female cadaver was noticed to have Riedel's lobe and beaver tail variant. Riedel's lobe appeared to be a tongue-like projection from the right inferior margin of the liver, almost reaching the level of the iliac crest. It was partially separated from the rest of the liver by a deep fissure. The left lobe was elongated, crossed the midline, and reached the left wall of the abdominal cavity after encircling the spleen. Splenomegaly was noticed, and the left lobe of the liver had a splenic impression. Riedel's lobe was drained by the middle hepatic vein (MHV) and supplied by the right branch of the portal vein (RPV). A similar variation of the beaver tail variant was noticed in an 85-year-old female cadaver. The left lobe of the liver crossed the midline and was related superior to the spleen. The right lobe of the liver and the spleen were normal. The beaver tail variant was drained by the left hepatic vein (LHV) and supplied by the left branch of the portal vein (LPV). These variations are prone to injuries and can be confused with the abdominal mass and could interfere with laparoscopic procedures.

Morphometric Analysis of the Neural Arch of C2 Vertebra in Indian Population.

BACKGROUND AND OBJECTIVE: The most common injuries to upper cervical spine are fractures of the second cervical vertebrae. The study aims to evaluate the morphometry of the neural arch of the second cervical vertebrae in the South Indian population. MATERIALS AND METHODS: Sixty-three second cervical vertebrae of undetermined gender and age without any gross defect were used for the study. The dimensions of neural arch, including superior articular facet, inferior articular facet, pediculoisthmic component, lamina, spinous process, foramen transversarium, and vertebral foramen, were measured by two independent observers using digital vernier caliper accurate to 0.1 mm and the data was analyzed. Descriptive statistics were obtained for the variables. Paired t-test was done to compare the measurements between right and left sides. RESULTS: There was no statistical difference between the right and left sides of the dimensions of superior articular facets, foramen transversarium, and the transverse diameter of inferior articular facet. The anteroposterior diameter of the inferior articular facets was more on the right side (P = 0.009). The width of the pediculoisthmic component in both the superior and inferior aspects was found to be less on the right side than that of the left (P = 0.006 and P = 0.031, respectively). The thickness in the middle one-third of laminae was optimum for bilateral safe screw insertion (≥4.0 mm) in 77% specimens. CONCLUSION: In summary, measurements of the transverse diameter of superior articular facet and thickness of lamina differed significantly from those reported in literature. This should be kept in mind while doing neurosurgery procedures in the Indian population.

Surgical anatomy of transversus abdominis muscle for transversus abdominis release.

Transversus abdominis release (TAR) is a myofascial release technique which helps in surgical repair of large ventral abdominal wall defects. In this procedure, the medial margin of muscular part of transversus abdominis (TA) is of great importance. Hence, the authors sought to describe the extent of medial margin of TA muscle. The surgical steps of TAR were performed in 10 formalin-fixed cadavers and distance between medial margin of TA muscle, lateral margin of rectus abdominis, to linea alba at five anatomical levels were documented respectively. The distance between the inferior epigastric vessels and the medial border of TA muscle was also noted. The TA muscle was within the posterior rectus sheath in all cadavers, at the xiphisternum (R, 61.6 mm; L, 58.9 mm), and at midway between xiphisternum and umbilicus (R, 25.4 mm; L, 27.1 mm). The TA muscle exited the posterior rectus sheath between this point and the umbilicus. The mean incongruity at the next three levels were -24.6 mm, -24.9 mm, and -22.9 mm respectively on the right and -21.4 mm, -19.9 mm, and -18.9 mm respectively on the left. The mean distance between the medial border of TA and inferior epigastric vessels was 18.9 mm on the right and 17.2 mm on the left. The muscular part of TA was incorporated within the posterior rectus sheath above the umbilicus, and it completely exited the rectus sheath at the umbilicus. This is contrary to the traditional understanding of posterior rectus sheath formation.

Relation of Langerhans cell size to buccal carcinoma.

Oral cancer decreases quality of life despite timely medical management. The carcinogens in tobacco products and their role in tumorigenesis are well documented. Langerhans cells (LCs) are a subset of antigen-presenting cells (APCs) that monitor the tumor microenvironment and engulf carcinogens and foreign bodies. We investigated the distribution and size of LCs and their relation to the mode of tobacco consumption and clinical outcome in patients with buccal carcinoma. We recruited patients with oral cancer who were scheduled for tumor excision and men with urethral stricture undergoing substitution urethroplasty using buccal mucosa. Normal and tumor-adjacent tissues were stained with CD1a antibody. The distribution and mean diameter of 100 LCs/patient were determined. We found significantly smaller LCs in patients who chewed only tobacco compared to those who consumed tobacco by other means. The size of LCs decreased significantly with progressive stages of malignant disease. We found that patients with larger LCs survived longer than those with smaller LCs during an average follow-up of 24 months. We suggest a relation between the size of LCs and clinical outcomes in patients with buccal carcinoma.

Effect of Silver Nitrate Cauterisation of Nasal Mucosa on Quality-of-Life and Histology in Patients with Intractable Chronic Rhinitis.

Patients with chronic rhinitis causing intractable sneezing which is non-responsive to conventional medication require alternative therapies. The aim of the study was to ascertain the effect of topical 10% silver nitrate solution on the inferior turbinate mucosa as well as quality of life in such patients. Patients with severe chronic rhinitis who failed conventional therapy had application of 10% silver nitrate solution to inferior turbinate mucosa. The number of sneezes/day and mini Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) score was noted before and 8 to 16 weeks after treatment. Pre- and post treatment turbinate biopsies were performed to assess histological changes. At baseline, 67 patients had a mean of 36.6 sneezes/day and mean mini RQLQ score of 4.0 ± 0.7. Pre-treatment biopsies showed epithelial denudation and hyalinization of basement membrane. Following 10% silver nitrate application, 64/67 (95.5%) patients showed significant reduction in number of sneezes both at 1 week (p < 0.001) and 8-16 weeks (mean = 5.5 ± 7.8; p < 0.001). Post- treatment mean global mini RQLQ score was also significantly reduced (mean = 1.3 ± 1.1; p < 0.001). A single application was sufficient in 70.1% patients. There were no complications. Squamous metaplasia (p = 0.005) and epithelial hyperplasia (p = 0.013) as well as epithelial and basement membrane restoration occurred following therapy. 10% silver nitrate solution application is an effective and safe office- based procedure which significantly reduces sneezing improves QoL with corresponding histological changes.

Aminoguanidine, a selective nitric oxide synthase inhibitor, attenuates cyclophosphamide-induced renal damage by inhibiting protein nitration and poly(ADP-Ribose) polymerase activation.

BACKGROUND: Cyclophosphamide (CP) is an antineoplastic agent that is used for the treatment of many neoplastic diseases. Renal damage is one of the dose-limiting side effects of CP. Recent studies show that nitrosative stress plays an important role in CP-induced renal damage. AIM: The purpose of our study was to investigate whether aminoguanidine (AG), a selective inducible nitric oxide synthase inhibitor, protects against CP-induced nitrosative stress and renal damage. METHOD: Renal damage was induced in rats by administration of a single injection of CP at a dose of 150 mg/kg body weight intraperitoneally. For the AG pretreatment studies, the rats were injected intraperitoneally with AG at a dose of 200 mg/kg body weight 1 h before administration of CP. The control rats received AG or saline alone. All the rats were killed 16 h after the administration of CP or saline. Pretreatment with AG prevented CP-induced nitration of protein tyrosine and poly(ADP-ribose) polymerase (PARP) activation. RESULT: Pretreatment with AG attenuated CP-induced renal damage. The present study demonstrates that AG is effective in preventing CP-induced renal damage and also that the protective effect is from its ability to inhibit nitric oxide-induced protein nitration and PARP activation. CONCLUSION: The present study shows that AG can prevent CP-induced renal damage by inhibiting protein tyrosine nitration and PARP activation. Thus, a more efficient and comfortable therapy can be achieved for patients in need of CP treatment. AG appears to be a promising drug for the prevention of nephrotoxicity of CP.

Prevalence of the additional head of quadriceps femoris in the South Indian population: a cadaveric and radiological study.

Quadriceps femoris is an extensor muscle in the anterior compartment of thigh and is traditionally taught to be composed of four heads. Recently, there is an increased interest in the occurrence of an additional muscle head of quadriceps femoris. But scientific knowledge regarding its incidence is lacking in the South Indian population. This study was done to confirm the presence of the additional head by routine anatomic dissection and radiological imaging techniques. Forty-one formalin fixed human cadaveric lower limbs were dissected and the morphology of the additional head was noted. Retrospective analysis of 88 MRI images of patients was done. The additional muscle head was present in 43.9% of the cadaveric lower limbs and was consistently located between the vastus lateralis and vastus intermedius. It originated from variable portions of the greater trochanter, intertrochanteric line, lateral lip of linea aspera and lateral surface of the shaft of femur and inserted either as a muscle belly or as an aponeurosis into the vastus intermedius (55.6%), vastus lateralis (22.2%) or directly into the base of the patella. It received its vascular supply from branches of the lateral circumflex femoral artery and was innervated by branches from the posterior division of the femoral nerve. In addition, the additional muscle head was identified by MRI and its incidence was reported to be 30.68% for the first time in living subjects. The result of this study provides additional information in understanding the morphology of the quadriceps femoris muscle.

Melatonin attenuates methotrexate-induced oxidative stress and renal damage in rats.

Nephrotoxicity is an adverse side effect of methotrexate (MTX) chemotherapy. The present study verifies whether melatonin, an endogenous antioxidant prevents MTX-induced renal damage. Adult rats were administered 7 mg/kg body weight MTX intraperitoneally for 3 days. In the melatonin pretreated rats, 40 mg/ kg body weight melatonin was administered daily intraperitoneally 1 h before the administration of MTX. The rats were killed 12 h after the final dose of MTX/vehicle. The kidneys were used for light microscopic and biochemical studies. The markers of oxidative stress were measured along with the activities of the antioxidant enzymes and myeloperoxidase activity in the kidney homogenates. Pretreatment with melatonin reduced MTX induced renal damage both histologically and biochemically as revealed by normal plasma creatinine levels. Melatonin pretreatment reduced MTX induced oxidative stress, alteration in the activity of antioxidant enzymes as well as elevation in myeloperoxidase activity. The results suggest that melatonin has the potential to reduce MTX induced oxidative stress, neutrophil infiltration as well as renal damage. As melatonin is an endogenous antioxidant and is non-toxic even in high doses it is suggested that melatonin may be beneficial in minimizing MTX induced renal damage in humans.

Protective effect of aminoguanidine against oxidative stress and bladder injury in cyclophosphamide-induced hemorrhagic cystitis in rat.

Cyclophosphamide (CP) is an antineoplastic agent that is used for the treatment of many neoplastic diseases. Hemorrhagic cystitis (HC) is a major dose limiting side effect of CP. Recent studies show that aminoguanidine, an inhibitor of inducible nitric oxide synthase is a potent antioxidant and prevents changes caused by oxidative stress such as depletion of antioxidant activity and tissue injury. The purpose of the study is to investigate the effect of aminoguanidine on parameters of oxidative stress, antioxidant enzymes and bladder injury caused by CP. Adult male rats were randomly divided into four groups. Control rats were administered saline; the AG control group received 200 mg/kg body wt of aminoguanidine; The CP group received a single injection of CP at the dose of 150 mg/kg body wt intraperitoneally. The CP + AG group received aminoguanidine (200 mg/kg body wt) intraperitoneally 1 h before the administration of CP. The rats were sacrificed 16 h after CP/saline administration. The bladder was used for light microscopic studies and biochemical studies. The markers of oxidative damage including protein carbonyl content, protein thiol, malondialdehyde and conjugated dienes were assayed in the homogenates along with the activities of the antioxidant enzymes, superoxide dismutase, glutathione peroxidase, catalase, and glutathione reductase and glutathione S transferase. In the bladders of CP treated rats edema of lamina propria with epithelial and sub-epithelial hemorrhage was seen. All the parameters of oxidative stress that were studied were significantly elevated in the bladders of CP treated rats. The activities of the antioxidant enzymes were significantly lowered in the bladders of CP treated rats. Aminoguanidine pretreatment prevented CP-induced oxidative stress, decrease in the activities of anti-oxidant enzymes and reduced bladder damage. The results of the present study suggest the antioxidant role for aminoguanidine in CP-induced bladder damage.

Nitrosative stress, protein tyrosine nitration, PARP activation and NAD depletion in the kidneys of rats after single dose of cyclophosphamide.

OBJECTIVES: Cyclophosphamide (CP) and its structural analogue ifosfamide are highly effective cytostatic drugs. While both cyclophosphamide and ifosfamide have severe urotoxic side effects, only ifosfamide is thought to be nephrotoxic. The nephrotoxicity of CP in generally overlooked because of normal plasma creatinine levels. Therefore, little information is available regarding the pathogenic mechanism of renal damage by CP. In the present study, we investigated the role of nitrosative stress in CP-induced renal damage. METHODS: The experimental rats received a single i.p. of 150 mg/kg body weight CP in saline and were killed 6 h or 16 h later. The control rats received saline. The kidneys were used for histological and biochemical analysis. Nitrotyrosine and poly (ADP-ribose) polymerase (PARP) were localized immunohistochemically as indicators of protein nitration and DNA damage, respectively. Nitrite, NAD and superoxide dismutase (SOD) activity were assayed in the kidney homogenates. RESULTS: The nitrite level in the kidneys of CP-treated rats was elevated twofold. The kidneys of CP-treated rats stained strongly for nitrotyrosine as well as for PARP. Significant decrease in oxidized NAD levels was also observed in the kidneys of CP-treated rats. The activity of the peroxynitrite sensitive enzyme SOD was significantly reduced in the kidneys of CP-treated rats. CONCLUSION: The results of the present study reveal that nitrosative stress may play an important role in CP-induced renal damage. It is suggested that protein nitration, PARP activation and NAD +/- depletion may play a critical role in the pathogenesis of cyclophosphamide induced renal damage.

Methotrexate-induced nitrosative stress may play a critical role in small intestinal damage in the rat.

Methotrexate (MTX), a structural analogue of folic acid, is widely used as a chemotherapeutic agent for leukemia and other malignancies. One of the major toxic effects of MTX is intestinal injury and enterocolitis .The mechanism of gastrointestinal toxicity of methotrexate has not been investigated completely. Therefore cancer chemotherapy has to be accompanied by symptomatic therapy such as antibiotics and anti-diarrheal drugs. It is important to investigate the mechanism by which methotrexate induces intestinal damage in order to perform cancer chemotherapy effectively by preventing the side effects. This study aimed at investigating whether nitrosative stress plays a role in methotrexate induced small intestinal damage using a rat model. Adult male rats were administered methotrexate at the dose of 7 mg/kg body weight intraperitoneally for 3 consecutive days and sacrificed 12 or 24 h after the final dose of methotrexate. Vehicle treated rats served as control. The intestinal tissue was used for light microscopic studies and markers of nitrosative stress including tissue nitrite level and nitrotyrosine. Myeloperoxidase (MPO) activity, a marker of neutrophil infiltration was also measured in intestinal homogenates. The villi were damaged at 12 h and the damage progressed and became severe at 24 h after the final dose of MTX. Biochemically, tissue nitrate was elevated fivefold at 12 h and fourfold at 24 h after the final dose of MTX as compared with control. Nitrotyrosine, measured immunohistochemically was detected in all the parts of the small intestine. Duodenum stained the most for nitrotyrosine, followed by ileum and then jejunum. The staining for nitrotyrosine was more intense at 24 h as compared with 12 h after the final dose of methotrexate. There was marked neutrophil infiltration as evidenced by increase in MPO activity in the small intestines. In conclusion, the results of the present study reveal that nitrosative stress may play a critical role in methotrexate induced small intestinal damage. Intervention studies using nitric oxide synthase inhibitors is being carried out in order to confirm the role of nitrosative stress in methotrexate induced small intestinal damage.

Morphological and morphometric analysis of accessory mental foramen in dry human mandibles of south indian population.

BACKGROUND: Mental foramen (MF) is an important landmark for administration of local anesthesia in surgical procedures involving the mandible. Additional mental foramina, called accessory mental foramina (AMF) transmitting branches of mental nerve, have been reported. Detection of AMFs in presurgical imaging may reduce postoperative pain in dental surgical procedures. Aim: The aim of the study was to study the incidence and morphometric analysis of accessory MF in the dry human mandibles of South Indian population. MATERIALS AND METHODS: Two hundred and sixty dry human mandibles were studied for the presence, location, shape of AMF, and its relation to MF. The horizontal diameter of AMF, and its distance from symphysis menti, the posterior border of mandible and from the base of mandible were measured and statistically analyzed. RESULTS AND CONCLUSIONS: In our study, AMF were present in 8.85% mandibles (unilateral - 7.6% [4.6% - left, 2.69% - right] and bilateral 1.6%). The most common position was below the second premolar (48.1%). AMF were round in shape (74%) and was often located either superomedial or inferolateral to MF. Their transverse diameter ranged from 0.5 to 1 mm. The AMF were situated at a mean distance of 2.96 mm from MF, 23.47 mm from symphysis menti, 11.24 mm from the lower border of the body of the mandible, and 57.35 mm from the posterior border of ramus of mandible. The knowledge of the presence of AMF and its dimensions would enable the clinicians to do mandibular procedures carefully and avoid injury to the branches of mental nerve that may be passing through it.

Morphology of Sigmoid Colon in South Indian Population: A Cadaveric Study.

INTRODUCTION: Sigmoid volvulus is a common etiological factor in acute large bowel obstruction. The increased length of sigmoid colon is attributed as one of the causes of sigmoid volvulus. AIM: The aim of this study was to find the morphology of sigmoid colon in South Indian population using cadavers. MATERIALS AND METHODS: The present study was performed with 31 cadavers used for teaching purpose. The sigmoid colon was classified into classical, long-narrow and long- broad types by their disposition in the abdominal cavity. The sigmoid loop's relation to pelvic brim was also observed and grouped as pelvic and suprapelvic in position. The length of sigmoid colon along the mesenteric and antimesenteric border, height and width of sigmoid mesocolon in relation to the pelvic brim and the root of mesentery were measured in the study. RESULTS: The study showed that the majority of the sigmoid colons fell into the classical type (47.6%). The sigmoid colon in pelvic position was significantly more prevalent. The mean length of sigmoid colon was 15.2 ± 4.4cm and 19.2 ± 6cm considering the pelvic brim and root of mesentery as reference points of measurement respectively. The mean length along antimesenteric border was 22.3 ± 7.9cm and 25 ± 8.7cm along the same reference points. The mean length of mesocolon height was 6.5 ± 3cm with reference to pelvic brim and 7.3 ± 3cm with reference to root of Sigmoid mesocolon respectively. The mean width of mesocolon was 7.4 ± 3cm (pelvic brim) and 8 ± 2cm (root of Sigmoid mesocolon) There was a positive correlation of sigmoid colon length with the height of the mesocolon. The gender analysis showed that males had statistically significant longer sigmoid colon and mesocolon. CONCLUSION: This study documents that the South Indian population has a more classical type of sigmoid colon and that the anatomical dimensions of sigmoid colon and its mesocolon is significantly longer in males.