Muscle Attachment Research Articles

Comparison of Axial Symptoms and Limitations of Activities of Daily Living Accompanying Reduced Neck Mobility After Cervical Laminoplasty Preserving C2 Muscle Attachments With and Without C2 to T1 Instrumented Fusion.

ObjectiveMuscles are usually detached from C2 to facilitate C2 pedicle screw insertion. The aim of this study was to compare 1-year postoperative axial symptoms and limitations in activities of daily livings (ADLs) accompanying reduced neck mobility between 2 procedures in which all C2 muscle attachments are preserved: laminoplasty and C2 to T1 fusion (LPF group: n=15) and laminoplasty alone (LP group: n=26). MethodsWe examined axial symptoms and limitations in ADLs using the Japanese Orthopedic Association Cervical Myelopathy Evaluation Questionnaire. We also examined related factors, including the occiput (O)–C7 angle in extension and flexion, and the rotational and O–C2 ranges of motion (ROM). ResultsThe postoperative decreases in the O–C7 angle in flexion (27.8° vs. 9.4°) and rotational ROM (40° vs. 15°), as well as the compensating postoperative increase in the O–C2 ROM (11.7° vs. 2.3°), were significantly greater in the LPF group. Most of the axial symptoms were similar between groups. The ability to perform ADLs tended to worsen more frequently in the LPF group, but the difference did not achieve significance. ConclusionPostoperative changes in axial symptoms and loss of ROM were not obstacles affecting patients’ ability to perform ADLs after laminoplasty with muscle-sparing C2 to T1 fusion.

An Elongated Mental Spine: Case Report

AbstractThe mental spines (superior and inferior), also called the genial tubercles, are located in the midline on the lingual surface of the mandible. Normally, the mental spine consists of a superior pair and an inferior pair of prominences and is of small size. The mental spine provides muscle attachments to the genioglossus muscle, which attaches to the superior pair, and to the geniohyoid muscle, which attaches to the inferior pair. Here, we report a case of the mandible with an elongated mental spine harvested from a 57-year-old Caucasian woman’s cadaveric head. The dimensions of the elongated mental spine are 10.00 mm (length) × 2.72 mm (width) × 8.55 mm (height). Elongated mental spines are rarely reported as they are usually asymptomatic. Practitioners who intend to perform any procedures in the sublingual and submental regions should be aware of such structural variation.

Reappraisal of the morphology and phylogenetic relationships of the alligatoroid crocodylian Diplocynodon hantoniensis from the late Eocene of the United Kingdom

AbstractDiplocynodon is a genus of basal alligatoroid comprising nine species, which spanned the late Palaeocene to middle Miocene of Europe. Despite recent revisions of most Diplocynodon species, one of the earliest named and most complete, Diplocynodon hantoniensis, has not been re-described for over 150 years. This species is known from the remains of numerous individuals from the Priabonian (late Eocene) Headon Hill Formation, which crops out at Hordle (Hordwell) Cliff in Hampshire, United Kingdom. Here we re-describe and diagnose Diplocynodon hantoniensis, providing the first detailed description of postcranial anatomy in Diplocynodon, and indeed any basal alligatoroid. Diplocynodon hantoniensis is diagnosed by four autapomorphies, including retention of the ectopterygoid–pterygoid flexure through ontogeny and a unique anterior process of the ectopterygoid adjacent to the posteriormost maxillary alveoli. A critical review of previously referred remains from elsewhere in Europe and the USA restricts Diplocynodon hantoniensis to the late Eocene of the UK. Through comparisons with extant crocodylians, the well-preserved postcranial skeleton enables the interpretation of numerous muscle attachments in the forelimbs and hindlimbs, providing a potentially rich source of character data for future phylogenetic analyses. Based on a comparison of humeral morphology between a large sample of crocodylian species, we outline two new morphological characters in the humerus. We include D. hantoniensis in a phylogenetic analysis, including all putative Diplocynodon species (103 taxa scored for 187 characters). We use four different character-weighting schemes: equal weighting, implied weighting (k value = 8) and extended implied weighting with k-values of 4 and 8. In general, these weighted analyses produce congruent results with the equal-weights analysis, and increase the resolution within Diplocynodon. We recover a monophyletic Diplocynodon in three of the four analyses. However, the fourth analysis, with the strongest downweighting of homoplastic characters and missing data (extended implied weighting with k = 4), recovers the Palaeocene Diplocynodon remensis outside Diplocynodon. Our comprehensive revision of one of the most completely known Diplocynodon species facilitates comparisons in the genus, as well as between other basal alligatoroids, and forms the basis for comparing postcranial anatomy in other fossil crocodylians.

Triticeal cartilage calcification

The triticeal cartilage (TC) is a tiny oval-shaped cartilage located at the lateral border of the thyrohyoid membrane between the hyoid bone greater horn and the thyroid cartilage superior horn. The exact function o TC is unknown; it has been proposed that TC was the site of the attachment for the triticeoglossus muscle. On panoramic radiographs, calcified TC may be observed in the soft tissues of the pharynx region, positioned inferior to the greater horn of the hyoid bone and adjacent to the superior border of the C4 vertebrae. The major concern of a calcified TC found incidentally in a routine radiographic examination is the differentiation between this alteration and other calcified tissue manifestations that require additional investigations, such as carotid calcified atheroma artery or other neck pathology such as foreign bodies. Thus, this report describes 3 cases in which TC calcifications were incidentally found in panoramic radiographs.

Shoulder girdle resection: surgical technique modification and introduction of a new classification system

ObjectiveDifferent classification systems for surgical tumor resections in the proximal humerus and scapula have been described, but none are specific or have been recently revised. The purpose of this article is to report modified surgical techniques and a new classification system for resections in the humerus and scapula.MethodsThirty-two patients with shoulder girdle bone tumors were operated upon. Two separate new classifications were assigned to resections in the humerus (types I–IV) and scapula (types I–III). An annotation is added to signify deltoid preservation (A) or sacrifice (B). Modified surgical techniques were devised.ResultsFor extra-articular resections of the proximal humerus, we show that sacrificing the acromion and coracoid process is not required. Preservation of these structures can improve cosmetic shoulder outcome. For tumors with no large medial component, we show that there is no need to detach the muscle attachment from the coracoid process allowing earlier elbow extension postoperatively. After a mean follow-up period of 46 months, only two patients developed local recurrence. Postoperative infection was seen in two and stem loosening in one patient. The average MSTS functional score for all patients was 83%.ConclusionOur modified surgical techniques saved structures which were unnecessarily resected with no advantage in surgical series. We reserved the integrity of more muscular tissues and attachments leading to less restriction during the rehabilitation process. This new classification system is realistic, easy to implement, and applicable to all patients.

A Reevaluation of the Gritti-Stokes (Above-Knee) Amputation for the Nonambulatory Patient

To reevaluate the benefits of a Gritti-Stokes amputation (GSA), as an alternative to the traditional above-knee amputation (AKA), in patients who are nonambulatory or not a candidate for a below-knee amputation (BKA). A fish-mouth incision is fashioned below the tibial tuberosity into the popliteal crease, resulting in an anterior soft tissue flap and smaller posterior soft tissue flap. Thus the incision line will be on the posterior thigh, instead of the end of the stump. The patellar tendon is detached from the anterior tibial tuberosity, then the dissection is carried proximally behind the patellar tendon and the adjoining tendons of the vastus medialis and vastus lateralis, until the patella can be flipped over to expose the posterior patellar surface and joint capsule. The patellar's posterior surface is shaved down flat to medulla bone, with an electric small-toothed bone saw and large bur. The femur is then cleared circumferentially at its base. The foot is then placed at 90°, creating a 45-degree angle between the femur and the tibia, and the femur is then transected with a Gigli saw near the base or just above the base, depending on the size of the patellar surface area. This creates a 45-degree angle to the femur posteriorly, which allows the shaved patella to be secured to the end of the femur, with less chance of shifting. The fascia is then circumferentially closed around the patella and femur. Then, the remnant patellar tendon is sutured to the tendons of the posterior compartment. The dermis and skin are then closed in the standard tension-free manner using 2-0 interrupted vicryl sutures, followed by interrupted 2-0 nylon vertical mattress sutures. The dressing consisted of a single layer of ADAPTIC Non-Adhering Dressing to allow drainage, gauze fluffs, 6-inch kerlix, and finally a 6-inch ACE wrap was applied. The dressings are left intact for 2-3days and then replaced daily thereafter. A retrospective chart review was performed to identify patients who had undergone a GSA from January 2016 to September 2017 by a single surgeon. Estimated blood loss (EBL), operative time, and perioperative and postoperative complications were assessed. A total of 16 GSAs were performed on 15 patients by a single surgeon between January 7, 2016 and September 19, 2017. In our series, intraoperative outcomes were notable for an average EBL of 114mL, lower than the traditional AKA (average EBL: 300-500mL) with comparable operative times as short as 90min (skin incision to dressing). No transfusions were required in the GSA group (postop days: 1-4) compared with traditional AKA group which required an average of 2.1 units. Postoperative outcomes showed low complication rates. Postoperative complications were limited to 2 cases of a stump infection, which were treated with local wound care and subsequently healed completely. One patient died from septic shock secondary to pneumonia unrelated to the GSA surgery. A reevaluation of the GSA in the nonambulatory patient population is warranted in the United States as an alternative to the traditional AKA whenever possible. Our experience with a small series of GSA's has yielded promising advantages including potential for decreased blood loss and fewer complications in the postoperative period when compared with the standard AKA. Retained muscle attachments facilitate increased limb function and allow use of slide joint prosthetics, which are gaining popularity for ambulatory patients. The thickened skin and subcutaneous tissues overlying the patella, and the posterior incision have the potential benefit of protection against trauma and osteomyelitis seen with traditional AKA, in which case the open ended medullary bone is deep to the incision. We believe that for these same reasons the GSA should be considered in the nonambulatory patient as well.

Superficial, suprahyoid, and infrahyoid neck musculature in naked mole-rats (Heterocephalus glaber): Relative size and potential contributions to independent movement of the lower incisors.

Naked mole-rats (Heterocephalus glaber) are fossorial, eusocial rodents that exhibit the unusual capability of moving their lower incisors independently in lateral and rostroventral directions. The evolution of this trait would presumably also involve concurrent alterations in neck musculature to support and control movements of the lower incisors. In order to assess morphological adaptations that might facilitate these movements, we performed detailed dissections of the neck musculature of adult naked mole-rats. In addition to characterizing attachment sites of superficial, suprahyoid, and infrahyoid musculature, we also quantified muscle mass and mandibular features thought to be associated with gape (condyle height, condyle length, and jaw length). Based on muscle attachment sites, the platysma myoides may contribute to lateral movement of the lower incisor and hemi-mandible in naked mole-rats. The large digastric muscle is likely to be a main contributor to rostroventral movement of each lower incisor. The geniohyoid and mylohyoid muscles also likely contribute to rostroventral movements of the lower incisors, and the mylohyoid may also produce lateral spreading of the hemi-mandibles. The transverse mandibular (intermandibularis) muscle likely serves to reposition the lower incisors back to a midline orientation following a movement.

An Enigmatic Small Neosuchian Crocodyliform from the Woodbine Formation of Texas.

New discoveries at the Arlington Archosaur Site (AAS), a Cenomanian (Late Cretaceous) locality in north-central Texas, are filling gaps in our knowledge of mid-Cretaceous Appalachian ecosystems, which remain poorly characterized. The AAS is notable because it preserves a diverse crocodyliform record. As seen in other sites that preserve four or more crocodyliform taxa, the species present at the AAS exhibit different snout shapes and body sizes, indicating that this high diversity of sympatric species was likely sustainable due to niche partitioning. Here we describe Scolomastax sahlsteini gen. et sp. nov., a new species of crocodyliform from the AAS, currently known from a partial right mandibular ramus. This species differs from other crocodyliforms in possessing features associated with durophagy or omnivory, including a shortened mandible, reduced tooth count, heterodonty, a dorsally expanded surangular, and enlarged attachments for jaw adductor muscles. Our phylogenetic analysis places this new taxon within Eusuchia as a member of Paralligatoridae and sister taxon to Paralligator gradilifrons. Scolomastax sahlsteini extends the record of paralligatorids into the Late Cretaceous of North America. This discovery represents the first appearance of this clade on the poorly known landmass of Appalachia, supporting a biogeographic connection between North America and Asia in the Early Cretaceous prior to completion of the Western Interior Seaway. However, relationships among other endemic crocodyliforms and tree instability within Paralligatoridae suggest further analysis is needed to resolve phylogenetic and biogeographic relationships (http://zoobank.org/urn:lsid:zoobank.org:pub:DC114471-6687-4BB5-8FAE-96F7278B1DAF). Anat Rec, 303:801-812, 2020. © 2019 Wiley Periodicals, Inc.

Pharyngeal Jaws Converge by Similar Means, Not to Similar Ends, When Minnows (Cypriniformes: Leuciscidae) Adapt to New Dietary Niches.

Convergent evolution is at the forefront of many form-function studies. There are many examples of multiple independent lineages evolving a similar morphology in response to similar functional demands, providing a framework for testing hypotheses of form-function evolution. However, there are numerous clades with underappreciated convergence, in which there is a perceived homogeneity in morphology. In these groups, it can be difficult to investigate causal relationships of form and function (e.g., diet influencing the evolution of jaw morphology) without the ability to disentangle phylogenetic signal from convergence. Leuciscids (Cypriniformes: Leuciscidae; formerly nested within Cyprinidae) are a species-rich clade of fishes that have diversified to occupy nearly every freshwater trophic niche, yet are considered to have relatively low morphological diversity relative to other large freshwater clades. Within the North American leuciscids, many genera contain at least one herbivore, insectivore, and larvaphage. We created 3D models from micro-computed tomography scans of 165 leuciscid species to measure functionally relevant traits within the pharyngeal jaws of these fishes. Using a published phylogeny, we tested these metrics for evolutionary integration, phylogenetic signal, and correlation with diet. Measurements of the pharyngeal jaws, muscle attachment areas, and teeth showed strong positive evolutionary correlation with each other and negative evolutionary correlation with measurements of the inter-ceratobranchial ligament (ICB ligament). Using diet data from published literature, we found extensive dietary convergence within Leuciscidae. The most common transitions we found were between herbivorous and invertivorous taxa and between insectivore types (aquatic vs. terrestrial). We document a trade-off in which herbivorous leuciscids have large teeth, short ICB ligaments, and large muscle attachment areas, whereas insectivorous leuciscids showed the opposite pattern. Inverse patterns of morphological integration between the ICB ligament the rest of the pharyngeal jaw correspond this dietary trade-off, which indicates that coordinated evolution of morphological traits contributes to functional diversity in this clade. However, these patterns only emerge in the context of phylogeny, meaning that the pharyngeal jaws of North American leuciscids converge by similar means (structural changes in response to dietary demands), but not necessarily to similar ends (absolute phenotype).

The Comparative Skeletal Structure of Blenniella bilitonensis (Skippers) and Bathygobius fuscus (Remainers)

Intertidal Zone is an area with high biological diversity including vertebrates. In order to survive in area with rapid change of environmental condition, animals need to be adapted accordingly. One type of adaptations that mostly employed is structural adaptation specifically ones that related to locomotor performances. Differences on how to navigate during high tides or when the water level subsided as well as types of locomotion between skippers and remainers suggested that there might also be structural differences in their skeleton. This research is aimed to study the skeletal structure of two species that use different strategy in their locomotion. Two species of fish from two main groups of intertidal fish (skippers and remainers) were caught and preserved in 96% Ethanol. The skeletal preparation was made using Inouye’s Alizarin Red Alcyan Blue Method. Data were collected by comparing skeletal structure between two species particularly the axial (vertebrae) and appendicular (pelvic, pectoral, caudal fin) skeleton. Based on the observation, skippers and remainers skeletal features has been adapted to different function during locomotion. Modifications on pelvic, pectoral and caudal bones were found in skippers and remainers. In B. bilitonensis, there are fusion of bones, reduction of some structures and also smaller bone area to provide agility. In remainers, modification mostly found in pelvic and pectoral fin. Pelvic fins possess larger and more rigid basal lepidotrichia as it was used as an attachment apparatus while fish cling to the substrate during high tide. In B. fuscus, pectoral fins are used as main propellers during swimming instead of caudal fins, hence larger bones area to provide more muscle attachment are observed in this species

An experimental study on the induction of Graves′ hyperthyroidism with Graves′ ophthalmopathy in BALB/c mice by TSHR gene immunization

Objective To construct a model of Graves′ disease(GD) with (or) Graves′ ophthalmopathy(GO) in BALB/c mice by immunization with pcDNA3.1/TSHR289. Methods pcDNA3.1/TSHR289 was injected into the bilateral gastrocnemius muscle of 35 model mice and electroporation was immediately performed. 10 control mice were injected with sterile saline and electroporated, while 5 blank mice were injected with sterile saline only. Each group of mice was immunized at 1, 4, 7, and 10 weeks, respectively. Serum total T4, TSH, TSAb, and TSBAb were measured before immunization, 2 weeks after each immunization, as well as 5 and 8 weeks after the last immunization. CT scan was used to evaluate the morphological changes of the eyes of the mice.99mTcO4- imaging was used to measure the thyroid uptake function, and the pathological changes of the thyroid and orbital tissues were evaluated by HE staining. Results After the 2nd time immunization, the serum concentrations of TT4, TSAb and TSBAb in GD mice were significantly higher than those of control and blank groups(F=13.781, 31.435, 36.112, P<0.01, respectively). The TSH continued to be significantly lower than that of control and blank groups(F=13.966, P<0.01). After the 4th time immunizations, the ability of uptaking99mTcO4- in GD mice thyroid was significantly enhanced compared with the control group. The thyroid goiter with a large amount of lymphocyte infiltration, and the thyroid follicle was thin. CT scan of GO mice showed thickening and swelling of the extraocular muscles, and no abnormalities in tendon and muscle attachment points. HE staining showed thickening of extraocular muscle fibers, lymphocyte infiltration of extraocular muscles and orbital tissue, increased hyaluronic acid, and infiltration of fat cells. Conclusion GD or GO model can be successfully induced by multiple intramuscular injection of pcDNA3.1/TSHR289 in BALB/c mice. Key words: Graves′ disease; Graves ophthalmopathy; TSHR; Mice models; Electroporation

Teaching anatomy using an active and engaging learning strategy

BackgroundVarious evidence-based and student-centered strategies such as team-based learning (TBL), case-based learning (CBL), and flipped classroom have been recently applied to anatomy education and have shown to improve student engagement and interaction. These strategies shift the focus of teaching from knowledge transmission to knowledge construction by students and encourage the use of tasks. This study discusses the use of an active and engaging learning strategy to teach the musculoskeletal system to Year 1 MBBS students (Faculty of Medical Sciences, The University of the West Indies, Cave Hill, Barbados) and examines the correlation between assessment modalities and student performance.MethodsThe “Active and Engaging Learning Strategy” was used to assess student learning in the form of oral presentations. Students had presentations on muscle attachments, muscle actions, blood and nerve supply, and applied anatomy of the limb musculature. Questions on the limbs (Locomotor System) were included in pre and post-presentation spotters, in-course assessments, and final examinations. Percentages, paired t-test, independent sample t-test, and zero-order correlations were performed to confirm the results for the different objectives of the study.ResultsThe main modes of presentation chosen were poems (37.1%), followed by stories (21.2%), songs (11.4%), and skits (10.6%). The majority of students (84%) found the strategies beneficial and recommended such sessions for future cohorts (92%). Students achieved significantly better scores in post-presentation spotters (p < 0.01) and the marks of in-course and final examinations also showed significant improvement (p < 0.01).ConclusionOur study highlighted that the active and engaging learning strategy can be used as an effective learning tool in anatomy. Students were proactive in preparing the muscle presentations by utilizing their own creativity, curiosity, and intelligence. Further studies should be conducted using randomized controlled trials to assess the effectiveness of various learning strategies which could open a new door to medical education.

A non-archaeopterygid avialan theropod from the Late Jurassic of southern Germany.

The Late Jurassic 'Solnhofen Limestones' are famous for their exceptionally preserved fossils, including the urvogel Archaeopteryx, which has played a pivotal role in the discussion of bird origins. Here we describe a new, non-archaeopterygid avialan from the Lower Tithonian Mörnsheim Formation of the Solnhofen Archipelago, Alcmonavis poeschli gen. et sp. nov. Represented by a right wing, Alcmonavis shows several derived characters, including a pronounced attachment for the pectoralis muscle, a pronounced tuberculum bicipitale radii, and a robust second manual digit, indicating that it is a more derived avialan than Archaeopteryx. Several modifications, especially in muscle attachments of muscles that in modern birds are related to the downstroke of the wing, indicate an increased adaptation of the forelimb for active flapping flight in the early evolution of birds. This discovery indicates higher avialan diversity in the Late Jurassic than previously recognized.

Application of modified micro titanium plate for extensor attachment point reconstruction in open-door laminoplasty

Objective: To observe the effect of modified micro titanium plate for extensor attachment point reconstruction in open-door laminoplasty. Methods: From January 2016 to February 2017, 26 patients with cervical spondylotic myelopathy underwent open-door laminoplasty+modified micro-titanium plate fixation+extensor muscle attachment point reconstruction at Tianjin Hospital were enrolled in this study. There were 14 males and 12 females in this group, aged (59±18) years. The improvement of neurological function based on the Japanese Orthopedic Association (JOA) score and the changes cervical curvature based on the cervical curvature index (CCI), especially the atrophy of the back muscles and the occurrence axial symptoms were recorded and analyzed. Intra-group comparisons were performed by using repeated measures of variance analysis or paired t-test. Results: The operations were performed well without injury to spinal cord. The operation time was (116±32) min with a blood loss of (196±41) ml. The JOA scores was improved form 7.8±2.1 preoperatively to 13.5±3.4 three months after surgery, and 13.9±3.7 at the final follow up (F=30.619, P<0.05). The improvement rate of neurological function was 66%±13%. The CCI decreased from 14.3%±3.9% preoperatively to 13.7%±3.7% three months after surgery and 13.0%±3.3% at the last follow-up (F=0.829, P>0.05). The cross-sectional area of the posterior cervical muscle was (35.9±7.6) cm(2) before surgery, and it was (33.5±6.7) cm(2) at the last follow-up (t=1.208, P>0.05). The spinal cord drift distance was (2.6±0.5) mm. The axial symptoms occurred in three patients, the incidence rate was 11.5%. Conclusion: In the open-door laminectomy, modified micro titanium plate can maintain the stability of the cervical spine, it also can rebuild the extensor attachment points and reduce the atrophy of the posterior cervical muscles, which avoid the occurrence of kyphotic deformity and reduce the occurrence of axial symptoms.

Anatomical Basis for Lip Reconstruction: The Role of the Modiolus.

The aim of this study was to establish the anatomic basis for functional upper and lower lip reconstruction with locoregional flaps. This article is an anatomic fresh cadaver study. For lower lip reconstruction, the modified Bernard-Webster and Karapandzic flaps preserve the modiolus, buccinator, zygomaticus major muscle, and buccal branches of the facial nerve. The Bernard-Webster flap allowed for a larger oral aperture despite a larger defect, but required transection of the lower lip depressors and orbicularis oris. For upper lip reconstruction, the reverse fan flap preserves the modiolus and its muscle attachments. The reverse Karapandzic flap required transection of the lower lip depressors, buccinator, and the zygomaticus major. Locoregional flaps remain the workhorse for lip reconstruction. This study provides the anatomic basis for the modiolus and its muscular attachments that permit techniques such as the Bernard-Webster flap and the Karapanzic flap to achieve functional lip reconstruction with innervated and denervated tissue.

Prevalence of Bifid Zygomaticus Major Muscle.

Facial expression muscles have significant morphological variability, including its size, shape, attachment patterns, and prevalence. The zygomaticus major (ZMj) represents one such important structure involved in facial expressions. The bifid ZMj muscle is a known anatomical variation that clinically presents as a dimple in the cheek; however, its prevalence and variation with ethnicity and geography remains poorly understood. The authors performed the first meta-analysis examine and established the prevalence of bifid ZMj variant across different population groups. From 7 studies identified via electronic databases, the prevalence of bifid ZMj variant was most prominent in the American subgroup 34% (95% CI 22.3%-48%), followed by the Asian subgroup at 27.4% (95% CI 14.3%-46.1%) and European subgroup at 12.3% (95% CI 6.5%-22.1%). Subgroup difference was found to be statistically significant (P = 0.027). The overall prevalence of the bifid ZMj is 22.7% (95% CI 14.3%-34.2%). This contributes to the understanding of various facial muscle morphologies and attachment patterns, which have significant implications in surgical planning and procedures for facial reanimation and recreation of natural patient appearances.

Morphology of the tentorium in the ant genus Lasius Fabricius (Hymenoptera: Formicidae)

The tentorium is the internal skeleton of the head capsule of insects. Several studies have shown that the structure of the tentorium is an important factor not only for the morphology and systematics but also for the phylogeny and evolution. In ants, however, only three studies have reported tentorial morphology so far. We reveal the fundamental structure of the tentorium of the genus Lasius (Hymenoptera, Formicidae) and its minor variation among six species of the genus. Based on the results, we give new terminologies of the organ, presenting a schematic diagram of the tentorium. We clarify muscle attachment to the tentorium by constructing a three-dimension image of the tentorium and muscles. We then verify the attachment areas of the antennal muscles and maxillary adductor muscles on the tentorium. The results show that the muscular attachment areas are broader than previously thought. Our study indicates that the key to understanding the evolution of the tentorium is its functional morphology, in relation to the attachments of the muscles originating from the tentorium within the head capsule. This is the first report of the three-dimensional images of the ant tentorium and its attached muscles. The intra- and inter-specific variations of the tentorium is also reported for the first time.

Skull shape and the demands of feeding: a biomechanical study of peccaries (Mammalia, Cetartiodactyla)

A primary requirement of the mammalian skull is to exert forces on different foods and to resist the forces imposed on it during feeding. Skull shape patterns within and among mammals are generally well known, but the biomechanical relevance of this variation remains limited for some groups. By integrating geometric morphometric and biomechanical analyses, we test the hypothesis that skull shape in peccaries reflects biomechanical attributes to generate and dissipate powerful forces, presumably in response to tough foods. We obtained skull shape and size from 213 specimens of the three living peccary species and estimated bite force, bite stress at molars, bending and shear stress on the mandibular corpus, and condylar stress. We found larger estimated bite forces, greater resistance to bending loads, and lower stress emerging from the larger muscle attachment areas and shorter and deeper mandibular corpora for both Pecari tajacu and Tayassu pecari relative to Parachoerus wagneri. Peccaries (P. tajacu and T. pecari) with more powerful biomechanical attributes feed mainly on tougher foods (e.g., palm fruits). These results support the hypothesis that species eating tough foods tend to have a feeding morphology mechanically adapted to stronger bites and greater biting resistance, which must be closely reflected in their craniomandibular shape.

A heparin-functionalized woven stent graft for endovascular exclusion

With the increase of vascular diseases in recent years, it is of importance to develop an anti-occlusion stent graft, which can meet the requirements of transplants for a long term. In this paper, we describe a silk fibroin (SF)/heparin-functionalized bifurcated stent graft (BSG) using textile forming technology. The BSGs were prototyped based on seamless weaving technology, and the surface was modified with SF-loaded heparin under steam/air treatment to improve their patency. The physical properties such as thickness, water permeability, contact angle, mechanical properties, and in vitro drug release and coagulation time of the BSGs were examined. The results showed that heparin modification can improve its coagulation time, and the water permeability resistance of the BSGs reached 1.154 ± 0.854 mL/(cm2×min), while their thicknesses were just 0.085 ± 0.004 mm. The heparin release of the BSGs showed that the release time was prolonged upon steam treatment by means of the increase in the β-sheet structure and crystallinity of SF. The viability and attachment of human vascular smooth muscle (HVSM) cells cultured in the release of modified BSGs demonstrated that the modified BSGs could significantly inhibit the proliferation of HVSM cells. The heparin-functionalized BSG with satisfactory thickness, water permeability resistance and anti-occlusion function, which has potential applications in the treatment of vascular diseases.

Anatomic variant of the gracilis muscle: a case report

Gracilis is a medial thigh muscle that typically exhibits little anatomic variation. The muscle attaches proximally to the inferior pubic ramus. Unlike other adductors of the thigh, it inserts distally at the anteromedial aspect of the proximal tibia. The muscle and tendon are commonly used for reconstructive surgical procedures because of its ease of access as well as its consistent and abundant blood supply. Here we report a case of a unique unilateral anatomical variation in the gracilis muscle from an 84‐year‐old male cadaver. Variation in the distal attachment of the gracilis muscle was observed on the right side during routine dissection of the medial and posterior thigh compartments. Subsequent dissection determined innervation and muscular attachments. The skin and fascia lata were dissected to expose the medial thigh muscles, including the gracilis muscle. The following aspects were evaluated: (a) the origin and insertion of the muscle, (b) the measurements for the lengths and weights for the gracilis, semimembranosus, and semitendinosus muscles from both limbs, and c) the distance of the arterial pedicles from origin at the ischiopubic ramus for the gracilis muscles. Results showed the variant gracilis muscle inserted into the distal aspect of the semimembranosus and semitendinosus muscle bellies. As a result, the pes anserinus only contained tendons from the semitendinosus and sartorius muscles. The variant muscle was shorter and weighed less than the contralateral gracilis muscle. Two arterial pedicles inserted into the variant gracilis muscle belly as opposed to four on the contralateral side, suggesting reduced blood supply to the variant muscle. This report describes the details of the variation and its clinical significance in reconstructive surgery.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.