Revisiting the anatomy of myrtiformis muscle.

BACKGROUND AND PURPOSE: The nasal base muscles are of great functional importance in health and disease. Particularly, the one lacking terminological consensus, but often termed as myrtiformis muscle, which has been mostly omitted by anatomists may have significance for rhinoplasty. The purpose of the current study was to re-examine the anatomical features of myrtiformis muscle. MATERIALS AND METHODS: Conducted on 40 sides of 20 formalin-fixed amputated heads, we followed a dissection routine to fully expose the origin and insertion sites of the nasal base muscles. We measured the respective morphometric via digital caliper. RESULTS: Based on the number of bellies and their muscular attachment sites, we described an anatomical classification that consists of three different types of MM which had a single and broad origin. We classified the double-bellied muscle as Type 1 occurred in 10% (4/40), whereas the single-bellied ones as Types 2 and 3, occurred in 80% (32/40) and 10% (4/40), respectively. Measured distance between the medial margin of myrtiformis muscle origin and midline passing through the anterior nasal spine did not differ between any statistical comparisons (P > 0.05). CONCLUSION: We revisited the muscle which was at some occasions termed as myrtiformis muscle, depressor septi nasi or depressor alae nasi muscles. Considering that there are differential forms of the muscle with the same muscular origin but bearing single or double bellies and/or different insertion sites, our classification may overcome possible terminological confusion by ensuring single muscle term with easily distinguishable morphological types. We invite anatomists to enlarge the data set and comment on our classification, and surgeons to conduct prospective examinations to add deeper insight regarding the functional importance of anatomical classifications by correlating pre vs post-operative functional differences.

Testing the suitability of neuroanatomical tracing method in human fetuses with long years of postmortem delay.

PURPOSE: Human tissues in gross anatomical archives with long years of postmortem delays are considered suboptimal relative to recently fixed materials for neuroanatomical tracing studies, yet efficacy of neuroanatomical tracing on archival fetal tissues largely unexplored. We aimed to explore the suitability of human archival tissue in neuroanatomical tracing with lipophilic carbocyanine dyes. METHODS: We used crystal and paste forms 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI) and analogues for neuroanatomical tracing on different peripheral nerves in 15-18-year archival old formalin-fixed human fetuses. We employed bright-field, fluorescent and confocal microscopy to visualize the peripheric nerve traces, spinal cord and vibratome cut sections. Fluorescent signal of the dyes on epineurium and on axonal membranes were visualized under fluorescence and confocal microscopes and performance of the dye diffusion was assessed by semi-quantitative image analysis. RESULTS: We followed up seven lipophilic dye embeddings in 16-28 gestational week-old human fetuses (n = 4) with 16.75 ± 1.29-year postmortem delay. The mean distance of distally moved carbocyanine dye diffusion measured on epineurium was detected as 25.11 ± 9.1 mm. CONCLUSION: Based on the results of 13 distinct studies performed neuroanatomical tracing with human tissues in the immediate postmortem hours or days, average traced distance was 16.32 ± 15.95 mm, and a 95% confidence interval lower limit of 4.9 mm and upper limit of 27.73 mm. The tracing distances we observed in our current study fall entirely within this confidence interval. To our awareness, this is the first report to demonstrate that specific neuroanatomical tracing presented in axonal membrane level on peripheral nerves is possible on gross anatomical repositories.

DNA Methylation program in normal and alcohol-induced thinning cortex.

While cerebral underdevelopment is a hallmark of fetal alcohol spectrum disorders (FASD), the mechanism(s) guiding the broad cortical neurodevelopmental deficits are not clear. DNA methylation is known to regulate early development and tissue specification through gene regulation. Here, we examined DNA methylation in the onset of alcohol-induced cortical thinning in a mouse model of FASD. C57BL/6 (B6) mice were administered a 4% alcohol (v/v) liquid diet from embryonic (E) days 7-16, and their embryos were harvested at E17, along with isocaloric liquid diet and lab chow controls. Cortical neuroanatomy, neural phenotypes, and epigenetic markers of methylation were assessed using immunohistochemistry, Western blot, and methyl-DNA assays. We report that cortical thickness, neuroepithelial proliferation, and neuronal migration and maturity were found to be deterred by alcohol at E17. Simultaneously, DNA methylation, including 5-methylcytosine (5mC) and 5-hydroxcylmethylcytosine (5hmC), which progresses as an intrinsic program guiding normal embryonic cortical development, was severely affected by in utero alcohol exposure. The intricate relationship between cortical thinning and this DNA methylation program disruption is detailed and illustrated. DNA methylation, dynamic across the multiple cortical layers during the late embryonic stage, is highly disrupted by fetal alcohol exposure; this disruption occurs in tandem with characteristic developmental abnormalities, ranging from structural to molecular. Finally, our findings point to a significant question for future exploration: whether epigenetics guides neurodevelopment or whether developmental conditions dictate epigenetic dynamics in the context of alcohol-induced cortical teratogenesis.

Internal supravesical hernia accompanied with anomalous fold formations: a cadaveric case report.

During the abdominal dissection of a 67-year-old male cadaver, an unusual peritoneal fold was encountered on the inner surface of the anterior abdominal wall. The peritoneal fold had two parts: the anterior part was located at the midsagittal plane including dispersed urachus remnants, the other part was located at the coronal plane with a triangular shape at the posterior edge of the sagittal part. Remnants of the umbilical arteries were ascending in the lateral margins of the coronal part. Accordingly, two peritoneal sacs were formed on both sides of this abnormal fold. Part of the small bowel herniated into the left peritoneal sac situated on the left side of the bladder. Although the aperture of the hernia sac was at the lateral side of the remnant of the umbilical artery which is concordant with the normal position of the medial inguinal fossa, the bottom of the sac was found to be located at the supravesical region. Therefore, this case was interpreted as an internal supravesical hernia with an unusual course. Although these rarely seen internal supravesical hernias in the literature were reported to be observed either preoperatively or postoperatively, to our knowledge our case is the first to be revealed in a cadaver which in detail enabled us to examine the features of this unique peritoneal variation and accompanying anatomic structures that caused hernia formation.

A rare combination of vascular variations of both kidneys.

Bilateral variations of renal vessels were encountered during the dissection of a 54-year-old male cadaver. There were triple renal arteries bilaterally, double renal veins on the right, and an unusual formation of renal vein on the left side. A bilateral occurrence of triple renal arteries has not been encountered in the literature, so does an incidence. Additional renal vessels have the potential to cause clinical complications such as hydronephrosis. Their existence has utmost importance in surgical and radiological interventions and radiological examinations.

DNA methylation program in developing hippocampus and its alteration by alcohol.

During hippocampal development, the Cornus Ammonis (CA) and the dentate gyrus (DG) undergo waves of neurogenesis and neuronal migration and maturation independently. This stage is widely known to be vulnerable to environmental stresses, but its underlying mechanism is unclear. Alcohol exposure has been shown to alter the expression of genes that regulate the fate, survival, migration and differentiation of pyramidal and granule cells. Undermining this process might compromise hippocampal development underlying the learning and memory deficits known in Fetal Alcohol Spectrum Disorders (FASD). We have previously demonstrated that DNA methylation was programmed along with neural tube development. Here, we demonstrated that DNA methylation program (DMP) proceeded along with hippocampal neuronal differentiation and maturation, and how this DMP was affected by fetal alcohol exposure. C57BL/6 mice were treated with 4% v/v ethanol through a liquid diet along with pair-fed and chow-fed controls from gestation day (E) 7 to E16. We found that a characteristic DMP, including 5-methylcytidine (5mC), 5-hydroxylmethylcytidine (5hmC) and their binding proteins, led the hippocampal neuronal differentiation and maturation spatiotemporally as indicated by their phenotypic marks in the CA and DG pre- and post-natally. Alcohol hindered the acquisition and progression of methylation marks, and altered the chromatin translocation of these marks in the nucleus, which was correlated with developmental retardation.

Anatomical variations of the foramen magnum, occipital condyle and jugular tubercle.

AIM: The foramen magnum (FM) is a unique and complex anatomical region. The occipital condyle (OC) and jugular tubercle (JT) are the main bony structures which obscure the anterolaterally situated lesions of the FM.The aim of this study was to revisit the anatomy of the FM region and assess variations of the surrounding structures. MATERIAL AND METHODS: Observations, on thirty dry skulls (dried specimens, 60 sides) and ten formalin-fixed cadaveric heads with perfused vessels, were carried out to define the microsurgical anatomy of the FM region. Morphometric analysis and variations of the FM, OC, JT and hypoglossal canal (HC) were noted. Radiological assessment (3D-computed tomography) of the OC, JT, HC were also conducted on dry skulls. RESULTS: The short and long OC were demonstrated in 5% and 33% of the specimens, respectively. Flat formation of the JT was determined in 10% and tall JT was found in 23% of the specimens. The comparison of the anatomical measurements and the correspondent radiological mean values did not achieve statistical significance. CONCLUSION: The OC and JT are the main bony prominences obstructing the anterolateral surface of the brainstem. Neurosurgeons should be familiar with variations of the structures surrounding the FM in order to perform the safest and widest exposure possible.

Strain differences in developmental vulnerability to alcohol exposure via embryo culture in mice.

BACKGROUND: Prenatal alcohol exposure can result in varying degrees of neurodevelopmental deficits, growth retardation, and facial dysmorphology. Variation in these adverse outcomes not only depends on the dose and pattern of alcohol exposure but also on less well understood interactions among environmental, genetic, and maternal factors. The current study tested the hypothesis that fetal genotype is an important determinant of ethanol teratogenesis by evaluating effects of ethanol exposure via embryo culture in 3 inbred strains of mice known to differ in the vulnerability of prenatal alcohol exposure in vivo. METHODS: Three strains of mice, C57BL/6N (B6), DBA/2 (D2), and 129S6/SvEvTac (129S6) were assessed in a whole embryo culture beginning on embryonic day 8.25, with or without alcohol administration at 88 mM for 6 hours followed by 42 hours culture in ethanol-free media. RESULTS: Contrasting strain differences in susceptibility were observed for the brain, the face, and other organ systems using the Maele-Fabry and Picard scoring system. The forebrain, midbrain, hindbrain, heart, optic vesicle, caudal neural tube, and hindlimbs of the B6 mice were severely delayed in growth, whereas compared to the respective controls, only the forebrain and optic vesicle were delayed in the D2 mice, and no effects were found in the 129S6 mice. A large number of cleaved (c)-caspase 3 positive (+) cells were found in regions of the brain, optic vesicles, cranial nerve nuclei V, VII, VIII, and IX as well as the craniofacial primordial; only a few were found in corresponding regions of the B6 controls. In contrast, only a small number of c-caspase 3 immunostaining cells were found in either the alcohol treated or the controls of the D2 embryos and in 129S6 embryos. The independent apoptotic markers TUNEL and Nile blue staining further confirmed the strain differences in apoptotic responses in both the neural tube and craniofacial primordia. CONCLUSIONS: Under embryo culture conditions, in which alcohol exposure factors and fetal developmental staging were controlled, and maternal and intrauterine factors were eliminated, the degree of growth retardation and the extent and type of neurodevelopmental teratogenesis varied significantly across strains. Notably, the 129S6 strain was remarkably resistant to alcohol-induced growth deficits, confirming a previous in vivo study, and the D2 strain was also significantly less affected than the B6 strain. These findings demonstrate that fetal genotype is an important factor that can contribute to the variation in fetal alcohol spectrum disorder.

Ectopic kidney with varied vasculature: demonstrated by CT angiography.

An ectopic kidney was found incidentally in a 20-year-old male patient during the abdominopelvic CT angiography. It was situated on the right side at the abdominopelvic junction, partly in the abdomen at the level of the intervertebral disc between L3 and L4 superiorly and partly in the greater pelvis at the level of the promontorium and close to the inferior border of the sacroiliac joints. It was supplied by two arteries which were nearly in the same caliber, and each of which branched from the common iliac arteries both close to the aortic bifurcation. There were two renal veins. The larger one which was emerging from the lateral part of the ectopic kidney was draining into the inferior vena cava. The smaller one which was the only hilar vessel of the ectopic kidney was draining into the left common iliac vein. The orthotopic left kidney was also supplied by two arteries from the abdominal aorta. Ectopic kidneys pose a problem for any planned surgical intervention given their anomalous blood supply. Ectopic position and varied vasculature can predispose to iatrogenic trauma during interventional radiological and laparoscopic procedures, and emergency operations.

Frequency, anatomical properties and innervation of axillary arch and its relation to the brachial plexus in human fetuses.

PURPOSE: "Axillary Arch" (AA) is the main musculotendinous variation of the axillary region. The aim of this study was to reveal the frequency, anatomical properties, and innervation of AA and its relation with brachial plexus in human fetuses. METHODS: In this study, 50 human fetuses (male: 20, female: 30), gestation age varied between 16 and 38 weeks (mean ± SD: 23.3 ± 5.3 week), were dissected at the anatomy laboratory of Mersin University, Faculty of Medicine. RESULTS: AA was found in 11 of the 50 fetuses, and in 3 of 11, it was bilateral. Among both sides, 6 of 14 AAs were on the right and 8 were on the left side. Seven of AA's (7% of the specimens) were in muscular and 7 (7%) of them were in musculotendinous structure. With regard to Testut's classification, six (6%) of them were of complete type, six (6%) were incomplete and two (2%) were concordant with both types. Three different types of AA were defined considering the shapes of the arches. According to our classification, seven of the AAs were of type 1, two of them were of type 2 and five of them were of type 3. Additionally, the incidence of the T2 spinal nerve joining the brachial plexus was significantly higher in the specimens with AA (p = 0.001). CONCLUSIONS: Each type of AA described in this study is thought to have individual clinical significance. Being aware of AA and its types can be important to determine a safe approach to the axillary region for surgeons. In addition, our results show the relation between the occurrence of AA and the variations in the formation of the proximal part of brachial plexus.

Bilateral and symmetrical heterotopic submandibular glands in the upper neck: case report.

During the neck dissection of a male cadaver, large heterotopic submandibular glands were encountered bilaterally in the upper neck. They were symmetrical, capsulated and lay deep to the superficial lamina of the superficial cervical fascia. Both glands were located in the submandibular and carotid triangles. The somewhat smaller orthotopic submandibular glands and the sublingual glands were in their normal anatomic location. Duct of the heterotopic gland united with the corresponding orthotopic submandibular gland's duct on each side and ended on the ipsilateral sublingual caruncle. Histopathologic examination of the heterotopic glands revealed seromucous (mainly serous) tissue. A bilaterally situated symmetrical heterotopic submandibular gland of this size has not heretofore been reported in the literature. The embryological and clinical significance of this case is discussed.

An unreported pattern of musculocutaneous and median nerve communication with multiple variations of biceps brachii: a case report.

An unreported pattern of communication between musculocutaneous (Mcn) and median nerve (Mn) with multiple variations of biceps brachii (Bb) was observed during the dissection of a male cadaver. The first branch of the Mcn ended in coracobrachialis (Cb). The second was the main Mcn piercing the Cb and giving its motor branches to the muscles of the anterior compartment of the arm. It then continued as the lateral cutaneous nerve of the forearm. The largest third branch also pierced the Cb distal to the main Mcn and communicated with the Mn which was classically formed by relevant roots of the medial and lateral cords. Additionally, a third head of Bb was observed bilaterally. Slips from the pectoralis major were inserted on the tendon of the third head on both sides. The origin of the third head was the greater tubercle to the left and the joint capsule to the right. These extremely rare patterns of both variations which were seen concomitantly in the same subject do not exist in the literature. Lack of awareness of such variations with different patterns of communications between Mcn and Mn might complicate surgical repair of the nerves. Knowing different patterns of Bb variations also have clinical importance as they also may cause compression of neurovascular structures or confuse a surgeon during surgical procedures.

An extremely rare bifurcation pattern of the caudal abdominal aorta: case report demonstrated by angiography.

An extremely rare bifurcation pattern at the caudal abdominal aorta was encountered on the pelvic angiography and MR angiography of a male patient. Instead of dividing into two common iliac arteries, the caudal abdominal aorta first gave the right external iliac artery at the level of the last lumbar arteries, then bifurcated into a right internal iliac artery and a left common iliac artery. The median sacral artery originated at this anomalous bifurcation. This high origin of the right external iliac artery and separate branching of these right iliac vessels from the abdominal aorta are important during the interventions in the region. We present the angiography findings and discuss the embryological origin of this unusual and unreported congenital anomaly.