Muscular Arrangement Research Articles

Convergent Conditions of Feedforward Control for Musculoskeletal Systems with Multi 1-DOF Joints Driven by Monoarticular and Biarticular Muscles

Muscles in the musculoskeletal system can only transmit forces in the tensile direction, thereby resulting in redundant actuation. This redundancy creates an internal force among the muscles. The musculoskeletal potential method uses a potential field generated by the internal force among muscles and performs a step input of the muscle tension balanced at the desired posture to achieve the point-to-point (PTP) position. This method is extremely simple and does not require any sensory feedback or complex real-time calculations, as long as the target muscle tension is achieved. However, it is known that convergence to a desired posture is strongly influenced by muscular arrangement. In a previous study, we limited our analysis to a specific structure with two joints and six muscles and explained the conditions for convergence to a desired posture. However, when the structure of the target system, number of joints, and number of muscles are different, the convergence conditions cannot be clarified using the previous method. In this study, we extend the previous method to a musculoskeletal system with multiple one degrees-of-freedom (DOF) joints driven by monoarticular and biarticular muscles. In this study, we clarify the conditions that must be satisfied by the muscular arrangement to converge to a desired posture in the musculoskeletal potential method and verify the results through simulation.

Functional morphology of cirri in the barnacle Amphibalanus improvisus (crustacea: Balanidae).

Barnacles rely heavily on their mobile cirri for food capture because of the sessile lifestyle. These filamentous food capturing devices are extended into the water current and perform undulating movements. Cuticular structures with corresponding musculature work together, to allow these highly repetitive movements. This paper studies the interplay between structure and function of the cirri using scanning electron microscopy (SEM), microcomputed tomography (µCT) and high-speed video recordings (HSV) in Amphibalanus improvisus. Barnacles use the external cuticle structures (denticles and setae) for efficient grooming, food capturing, and providing support for the muscular system responsible for movement control. Entanglement of the cirri during extension is probably avoided through an interlocking of the serrate setae on cirri IV-VI, creating a "zipper-like" effect, which was recorded here using the HSV. We analyzed the muscular arrangement using µCT and found a new flexor muscle in both the endo- and exopod of cirrus II. Supported by the intrinsic cirral muscles, the new flexor muscles may provide variable movements of the anterior cirri (cirri I-III), which is important for further food handling. Our results provide a foundation for further comparative studies of the feeding apparatus of barnacles and for possible implications in the area of bio-inspired robotics.

Elimination of factors contributing to the development of colo-esophageal anastomotic dehiscence following retrosternal colonic esophagoplasty performed for esophageal atresia correction

Aim. Development of methodology that would allow surgeons to decrease the risk of colo-esophageal anastomotic dehiscence following esophagoplasty through prevention of colonic transplant compression in the retrosternal tunnel and surgery facilitation.Material and methods. Ultrasound examination was carried out on 43 infants (22 boys and 21 girls) without sternal pathologies. The dorsal sternal angle and thickness of the upper and lower parts of the sternal manubrium were evaluated. The prominence and structure of muscular arrangement in various parts of the dorsal side of the sternal manubrium were examined in 15 infant patients. The results of treatment based on the method developed in accordance with the RF invention patent No. 2552095 were analyzed for infant patients (8 boys and 7 girls) suffering from esophageal atresia. 9 patients had fenestration of the sternal manubrium performed across its entire length, 6 children – in its upper segment only. X-ray control was used to detect colonic transplant compression. Significant difference between the variables in question in the examined groups was evaluated using the Mann-Whitney U test (M-W) for data measured on an ordinal scale.Results. The upper part of the sternal manubrium (above the attachment of the first rib) was found to exert the highest pressure on the transplant as it is statistically significantly thicker (M-W=4.44; p<0.01), being covered with a more prominent muscular layer (M-W=6.71; p<0.001) over a larger area (M-W=4.42; p<0.01) and considerably reclined. In infant age, the dorsal sternal angle is 164.9±0.8 degrees. Its value was consistently (M-W=2.66; p<0.01) higher in the girls' group with significant individual variations. Based on the collected data, an original technique was developed for individual approach to the resection of the manubrium sterni applied during retrosternal colonic esophagoplasty in 15 patients with esophageal atresia. No signs of colo-esophageal anastomotic dehiscence or transplant compression were revealed in any of those cases.Conclusion. The suggested method allows surgeons to assess in every case the narrowness of retrosternal space and individually select the scope of sternal manubrium resection to eliminate important factors contributing to the development of colo-esophageal anastomotic dehiscence after retrosternal esophagoplasty in cases of esophageal atresia thus facilitating the surgery and preventing transplant compression in the retrosternal tunnel.

Cranial muscle reconstructions quantify adaptation for high bite forces in Oviraptorosauria

Oviraptorosaurians are an unusual and probably herbivorous group of theropod dinosaurs that evolved pneumatised crania with robust, toothless jaws, apparently adapted for producing a strong bite. Using 3D retrodeformed skull models of oviraptorid oviraptorosaurians Citipati, Khaan, and Conchoraptor, along with the earliest diverging oviraptorosaurian, Incisivosaurus, we digitally reconstruct jaw adductor musculature and estimate bite force to investigate cranial function in each species. We model muscle length change during jaw opening to constrain optimal and maximum gape angles. Results demonstrate oviraptorids were capable of much stronger bite forces than herbivorous theropods among Ornithomimosauria and Therizinosauria, relative to body mass and absolutely. Increased bite forces in oviraptorid oviraptorosaurians compared to the earliest diverging oviraptorosaurian result from expanded muscular space and different cranial geometry, not changes in muscular arrangement. Estimated optimal and maximum possible gapes are much smaller than published estimates for carnivorous theropods, being more similar to the herbivorous therizinosaurian theropod Erlikosaurus and modern birds. Restrictive gape and high bite force may represent adaptation towards exploiting tough vegetation, suggesting cranial function and dietary habits differed between oviraptorids and other herbivorous theropods. Differences in the relative strength of jaw adductor muscles between co-occurring oviraptorids may be a factor in niche partitioning, alongside body size.

The three muscle layers in the pyloric sphincter and their possible function during antropyloroduodenal motility

This study was conducted to determine the muscular arrangement of the human pyloric sphincter using a comprehensive approach that involved microdissection, histology, and microcomputed tomography (micro‐CT). The stomachs of 80 embalmed Korean adult cadavers were obtained. In all specimens, loose muscular tissue of the innermost aspect of the sphincter wall ran aborally, forming the newly found inner longitudinal muscle bundles, entered the duodenum, and connected with the nearby circular bundles. In all specimens, approximately one-third of the outer longitudinal layer of the sphincter entered its inner circular layer, divided the circular layer into several parts, and finally connected with the circular bundles. Anatomical findings around the sphincter were confirmed in micro-CT images. The sphincter wall comprised three layers: an inner layer of longitudinal bundles, a middle layer of major circular and minor longitudinal bundles, and an outer layer of longitudinal bundles. The stomach outer longitudinal bundles were connected to the sphincter circular bundles. The inner longitudinal bundles of the sphincter were connected to the adjacent circular bundles of the duodenum.

Optimal Muscular Arrangement Using Genetic Algorithm for Musculoskeletal Potential Method with Muscle Viscosity

Muscle contractions (or equivalent mechanical elements) are responsible for joint movement in systems with musculoskeletal structure. Because muscles can only transmit force in the tensile direction in such systems, the internal force exists between the muscles. By utilizing the potential field generated by the internal force, the musculoskeletal potential method makes it possible to control the position without complex real-time calculations or sensory feedback by entering step-inputs of the balanced internal force at the target posture. However, the conditions of convergence to the target posture strongly depend on muscular arrangement. Previous studies have elucidated the mathematical conditions of the muscular arrangement; however, they provide sufficient conditions that must be satisfied by the muscular arrangement to converge to the target posture, which do not necessarily lead to optimal muscular arrangement conditions. This study proposes a method to determine the optimal muscular arrangement of a two-joint six-muscle system, wherein muscle viscosity is considered, that uses a genetic algorithm and an evaluation function considering the motion response time. The effect of the obtained muscular arrangement is verified in a simulation.

Regional Patterning in Tail Vertebral Form and Function in Chameleons (Chamaeleo calyptratus).

Previous studies have focused on documenting shape variation in the caudal vertebrae in chameleons underlying prehensile tail function. The goal of this study was to test the impact of this variation on tail function using multibody dynamic analysis (MDA). First, observations from dissections and 3D reconstructions generated from contrast-enhanced µCT scans were used to document regional variation in arrangement of the caudal muscles along the antero-posterior axis. Using MDA, we then tested the effect of vertebral shape geometry on biomechanical function. To address this question, four different MDA models were built: those with a distal vertebral shape and with either a distal or proximal musculature, and reciprocally the proximal vertebral shape with either the proximal or distal musculature. For each muscle configuration, we calculated the force required in each muscle group for the muscle force to balance an arbitrary external force applied to the model. The results showed that the models with a distal-type of musculature are the most efficient, regardless of vertebral shape. Our models also showed that the m. ilio-caudalis pars dorsalis is least efficient when combining the proximal vertebral shape and distal musculature, highlighting the importance of the length of the transverse process in combination with the lever-moment arm onto which muscle force is exerted. This initial model inevitably has a number of simplifications and assumptions, however its purpose is not to predict in vivo forces, but instead reveals the importance of vertebral shape and muscular arrangement on the total force the tail can generate, thus providing a better understanding of the biomechanical significance of the regional variations on tail grasping performance in chameleons.

Myoanatomy of three aberrant kinorhynch species: similar but different?

Aberrant kinorhynchs show several modifications deviating from the typical kinorhynch body plan, including a modified introvert with very elongated and flexible scalids, a weakly developed neck, and a slender trunk with less distinct segmentation. How these aberrant external features are reflected in the inner anatomy and how their aberrant body plan evolved are not understood. Here, we provide a comprehensive and comparative myoanatomical study of three putatively, distantly related worm-like species: Cateria styx, Franciscideres kalenesos and Zelinkaderes yong. Despite the weak external segmentation of the trunk, the studied species show a distinct segmental arrangement of the musculature. However, this arrangement is shifted posteriorly with respect to the external segmentation, because the extremely thin and flexible cuticle is lacking the apodeme-like cuticular thickenings (pachycycli) where the longitudinal muscles usually attach. The muscular arrangement in the three species is overall similar, yet, C. styx shows most resemblance to the allomalorhagid F. kalenesos, whereas the cyclorhagid Z. yong differs in several ways. This suggests a closer relationship of C. styx to Allomalorhagida. Whereas most kinorhynchs prefer muddy sediments, both the allomalorhagid and cyclorhagid worm-like kinorhynchs are mainly found in sandy environments, suggesting that a flexible, slender body evolved at least twice independently as an adaptation to the interstitial environment.

Locomotion in Anaspides (Anaspidacea, Malacostraca) – insights from a morpho-functional study of thoracopods with some observations on swimming and walking

Anaspidacea is probably the most enigmatic higher taxon within the Malacostraca. Representatives of the genus Anaspides are often considered “living fossils” due to their strong resemblance to their Triassic relatives. In comparison to other extant Malacostraca, they possess a high number of plesiomorphic characters. Anaspidacea are often combined with another freshwater taxon, Bathynellacea, into the Syncarida, but actual evidence for monophyletic Syncarida is weak. Other potential sister groups are Eucarida, Euphausiacea, or Euphausiacea + Peracarida. Like Euphausiacea, Mysidacea and “natant” decapods, Anaspidacea show what has been called a “caridoid facies”.In malacostracan crustaceans, a prominent mode of locomotion is swimming, as it almost certainly was for the malacostracans’ common ancestor. However, when considered in detail, swimming is found to take quite different forms in the various taxa. To obtain a better understanding of the evolution of swimming, we analyzed locomotion in several species of Anaspides endemic to Tasmania. The morphology of the protopodal and exopodal musculature as well as the exo- and endoskeletal structures of the thoracopods were examined using 3D reconstruction of CLSM- and μCT data. Various aspects of locomotion were documented and described using recording techniques including in-habitat underwater filming and macro high-speed recording.Our analysis shows the high level of complexity of the muscular arrangement and skeletal construction in the thoracopods of these - in many regards plesiomorphic - malacostracans, and demonstrates the presence of epipodal musculature. Our recordings provide insight into various aspects of locomotion of Anaspides, including the congruence of locomotive kinematics in swimming and walking. Our morphological findings and observations on locomotion in Anaspides are compared to findings in other malacostracan shrimps and discussed in a phylogenetic context, with our analysis providing further support for Xenommacarida (sensuRichter, 1999: Anaspidacea + Euphausiacea + Peracarida). Further, a new hypothesis for the origin of the ventral brood pouch, the marsupium, of Peracarida is discussed. On the basis of a comparison of their morphology and biology, the oostegites which form the marsupium are suggested to be derived thoracopodal endites as present in female Anaspides. Finally, an evolutionary scenario is presented and mapped on a cladogram in which the evolution of malacostracan swimming from a common caridoid ancestor up to the different taxa present today is discussed.

Brachiocephalic Muscular Arrangements in Cavioid Rodents (Caviomorpha): a Functional, Anatomical, and Evolutionary Study

In cursorial mammals, reduction or loss of the clavicle is usually associated with the constitution of the m. brachiocephalicus, a continuous muscle that extends from head and neck regions to the forelimb, protracting it during locomotion. Among caviomorph rodents, the Cavioidea are characterized by many adaptations that improve running performance, such as the presence of a brachiocephalic configuration of the mm. cleidomastoideus, cleido-occipitalis, and deltoideus pars clavicularis, a feature that was interpreted as one of the main modifications for speed in running. However, a comprehensive analysis of this muscular configuration in the Cavioidea is not yet available. In this study, we analyze the morphological diversity, homologies, functions, and evolutionary changes of those shoulder muscles in cavioids that constitute the m. brachiocephalicus in cursorial mammals. We hypothesize that a brachiocephalic muscular arrangement of these muscles has evolved in this group in relation to a swift mode of locomotion. Muscular dissections on seven species of cavioids were performed while myological data on three other species were taken from the literature. Our results indicate that all cavioids have a brachiocephalic arrangement of the mm. cleidomastoideus, cleido-occipitalis, and deltoideus pars clavicularis, whereas a second brachiocephalic arrangement constituted by the mm. omotransversarius and trapezius pars cervicalis is present only in the larger cavioids. Both muscular configurations act in protracting the forelimb during the gait, but we also hypothesize that the particular disposition of the m. omotransversarius around the shoulder joint of larger cavioids could also assist in the stabilization of this joint during fast half-bounding locomotion.

Geometric conditions of a two-link-and-six muscle structure based on internal force stability

In a musculoskeletal system, internal tensile forces are generated among the muscles because it is a redundant system. The balancing of the internal tensile forces for a given posture generates a potential field in the system. Therefore, the potential field is utilized for the sensorless feedforward position control and improvement of stability based on the feedback method. However, the stability of the internal tensile forces is strongly influenced by the muscular arrangement. Previous studies showed that a stable condition can be identified through the minimization of the potential at a desired posture, and the sufficient condition has been theoretically established; however, the geometric condition of the muscular arrangement has not been determined. To effectively exploit the characteristics of the internal tensile forces, the geometric condition must be elucidated in the design of a musculoskeletal system. This paper aims to clarify the geometric condition to generate stable internal tensile forces. Based on the conditions generating the potential that is minimum at the desired posture, the paper analyzes that the geometric condition on a musculoskeletal structure with two-link and six-muscle. Additionally, the identified condition is assessed based on simulations. As a result, we revealed the geometric condition of the muscular arrangement to generate stable internal tensile forces. By designing the muscular arrangement to satisfy the condition, the stability of the internal tensile forces is ensured, and consequently, a control method utilizing the characteristics of the internal tensile force is stably implemented.

Longitudinal muscular column in the prostatic urethral wall: Its form, shape, and possible function based on mathematical simulation in ejaculation.

The shape and function of the longitudinal muscular column (LMC) of the prostate have not been established in detail. The present study was undertaken to elucidate the roles of the LMC of the posterior wall of the prostatic urethra (PSU) in the emission phase of ejaculation by investigating the form and muscular arrangement of the LMC. Prostates and urinary bladders were obtained from 14 Korean adult cadavers. Nine specimens were histologically analyzed using hematoxylin and eosin, Masson's trichrome, and Verhoeff-van Gieson staining. Two specimens were scanned using microcomputed tomography (micro-CT), and all scanned images were reconstructed into a three-dimensional model. At the proximal level of the prostate, the ejaculatory ducts (EDs) and prostatic utricle (PU) together were surrounded by circular smooth-muscle fibers. However, at the seminal colliculus (SC) where the EDs and PU opened, they were mainly surrounded by an abundance of longitudinal fibers. The longitudinal fibers posterior to the EDs and PU formed a distinctive LMC in the posterior urethral wall. In histologic sections and micro-CT images, the LMC extended distally from the level of the SC to the level of the membranous urethra (MBU). We simulated a potential mechanism of LMC using a mathematical model of its movements. Comprehensive analyses based on in-depth assessment of histologic characteristics and micro-CT images demonstrated extension of the LMC from the level of the SC to the level of the MBU, enabling a better understanding of ejaculation physiology involving the LMC. These results suggest that the LMC in the posterior wall of the PSU is a critical component of ejaculation by facilitating the ejection of seminal vesicle fluid into the PSU via well-coordinated contractions.

Stability conditions of an ODE arising in human motion and its numerical simulation

This paper discusses the stability of an equilibrium point of an ordinary differential equation (ODE) arising from a feed-forward position control for a musculoskeletal system. The studied system has a link, a joint and two muscles with routing points. The motion convergence of the system strongly depends on the muscular arrangement of the musculoskeletal system. In this paper, a sufficient condition for asymptotic stability is obtained. Furthermore, numerical simulations of the penalized ODE and experimental results are described.

Oral sucker in Digenea: structure and muscular arrangement

Digeneans use oral and ventral suckers for attachment, locomotion, and feeding. The structure of these organs is rarely described in detail. I used fluorescent actin staining and confocal laser scanning microscopy to describe musculature arrangement in the oral sucker of eight digenean species (all Plagiorchiida). Scanning electron microscopy and light microscopy of histological sections were used for a general morphological description of the sucker structure. The musculature of the oral sucker is independent from the body wall and the internal muscles. The arrangement of the muscles within the oral sucker is complex; it includes up to 14 groups. Layers of transverse and meridional muscle fibers line the outer surface beneath tunica propria. Transverse muscle bands, meridional fibers, anterolateral groups, and circular or semicircular fibers of the sphincter are present at the rim of the oral sucker. Circular and longitudinal muscle fibers are found beneath the tegument of the buccal cavity. The bulk of the sucker consists of radial muscle bundles, but it also contains chordal muscle bundles, diagonal fibers, and wide lateral muscle bands. Based on the results, I propose that three features determine the complexity of musculature arrangement in the oral sucker: (1) bilateral symmetry of the sucker, (2) incongruity of the main body axis and the own axis of the sucker, and (3) regionalization of the sucker surface. The origin and functioning of the oral sucker are discussed.

The pelvic and hindlimb myology of the basal titanosaur Epachthosaurus sciuttoi (Sauropoda: Titanosauria)

ABSTRACT Epachthosaurus sciuttoi is a basal titanosaur from the early Late Cretaceous of central Patagonia, Argentina. Here, we present the reconstruction of the pelvic and hindlimb musculature of this titanosaur, based on the soft tissue data of extant archosaurs. The majority of the pelvic, hindlimb and pes muscles are within a decisive and positive level of inference. Comparison with a derived titanosaur such as Neuquensaurus, shows several morphological differences which are directly related with the muscular attachments, supporting differences about the musculature arrangement between these two sauropod dinosaurs. For example, the anterior projection of the preacetabular process of Neuquensaurus extends more laterally, whereas in Epachthosaurus the preacetabular process is laterally less extended. The fibular lateral tuberosity in Neuquensaurus is closer to the fibular head than it is in Epachthosaurus. The femoral fourth trochanter in Neuquensaurus is closer to the femoral head than it is in Epachthosaurus. Likewise, the caudofemoralis longus may have extended more distally in the tail in Epachthosaurus.These differences, among others, may have influenced the muscular arrangement and, therefore, the locomotor function abilities of these titanosaurs. Finally, this myological description of Epachthosaurus, where twenty one muscles were reconstructed, constitutes useful data for researches interested in functional anatomy.

Forelimb musculature and osteological correlates in Sauropodomorpha (Dinosauria, Saurischia).

This contribution presents the forelimb muscular arrangement of sauropodomorph dinosaurs as inferred by comparisons with living archosaurs (crocodiles and birds) following the Extant Phylogenetic Bracket approach. Forty-one muscles were reconstructed, including lower limb and manus musculature, which prior information available was scarce for sauropodomorphs. A strong emphasis was placed on osteological correlates (such as tubercles, ridges and striae) and comparisons with primitive archosauromorphs are included in order to track these correlates throughout the clade. This should help to elucidate how widespread among other archosaurian groups are these osteological correlates identified in Sauropodomorpha. The ultimate goal of this contribution was to provide an exhaustive guide to muscular identification in fossil archosaurs and to offer solid anatomical bases for future studies based on osteology, myology, functional morphology and systematics.

Bapx1 upregulation is associated with ectopic mandibular cartilage development in amphibians

BackgroundThe emergence of novel structures during evolution is crucial for creating variation among organisms, but the underlying processes which lead to the emergence of evolutionary novelties are poorly understood. The gnathostome jaw joint is such a novelty, and the incorporation of bapx1 expression into the intermediate first pharyngeal arch may have played a major role in the evolution of this joint. Knockdown experiments revealed that loss of bapx1 function leads to the loss of the jaw joint, because Meckel’s cartilage and the palatoquadrate fuse during development. We used Xenopus laevis and Ambystoma mexicanum to further investigate the function of bapx1 in amphibians. Bapx1 expression levels were upregulated through the use of Ly-294,002 and we investigated the potential consequences of the enhanced bapx1 expression in amphibians to test the hypothesized joint inducing function of bapx1.ResultsWe show that Ly-294,002 upregulates bapx1 expression in vivo. Additionally, ectopic mandibular arch derived cartilages develop after Ly-294,002 treatment. These ectopic cartilages are dorsoventrally oriented rods situated lateral to the palatoquadrate. The development of these additional cartilages did not change the muscular arrangement of mandibular arch-derived muscles.ConclusionsDevelopment of additional mandibular cartilages is not unusual in larval anurans. Therefore, changes in the bapx1 expression during evolution may have been the reason for the development of several additional cartilages in the larval anuran jaw. Furthermore, our observations imply a joint-promoting function of bapx1, which further substantiates its hypothetical role in the evolution of the gnathostome jaw joint.

Molecular characterization and confocal laser scanning microscopic study of Pygidiopsis macrostomum (Trematoda: Heterophyidae) parasites of guppies Poecilia vivipara.

Pygidiopsis macrostomum and Ascocotyle (Phagicola) pindoramensis (Digenea: Heterophyidae) parasitize guppies as intermediate hosts and, respectively, fish-eating mammals or birds as definitive hosts. Heterophyids have zoonotic potential, and molecular studies associated with morphological and ecological aspects have helped to clarify their taxonomy and phylogeny. Poecilia vivipara naturally parasitized by metacercariae of both species (100% prevalence) exhibit no external signs of parasitism. In this work, four new sequences of P.macrostomum (18S rDNA, 28S rDNA and ITS2 rDNA) and one new sequence of A. (P.) pindoramensis (mtDNA cox-1) are presented. Phylogeny reconstructions linked P.macrostomum to other heterophyids, but the separation of the Heterophyidae and Opisthorchiidae remains unclear. Additionally, we used indirect immunocytochemistry and the phalloidin-fluorescence techniques allied with confocal laser scanning microscopy to describe muscular and neuronal structures of P.macrostomum. A complex arrangement of muscular fibres is associated with the tegument, suckers, gut and reproductive system. Radial fibres around the ventral sucker are thick, branched and extend to the body wall. High-resolution confocal imaging revealed a typical digenean muscular arrangement and important heterophyid morphological traits. These data will support future control measures to reduce the parasitism in guppies reared in fish farming systems, especially for aquarium and experimental purposes.

2リンク6筋を有する筋骨格システムにおけるフィードフォワード位置決めのための筋配置条件

2リンク6筋を有する筋骨格システムにおけるフィードフォワード位置決めのための筋配置条件

Muscular Arrangement and Muscle Attachment Sites in the Cervical Region of the American Barn Owl (Tyto furcata pratincola).

Owls have the largest head rotation capability amongst vertebrates. Anatomical knowledge of the cervical region is needed to understand the mechanics of these extreme head movements. While data on the morphology of the cervical vertebrae of the barn owl have been provided, this study is aimed to provide an extensive description of the muscle arrangement and the attachment sites of the muscles on the owl’s head-neck region. The major cervical muscles were identified by gross dissection of cadavers of the American barn owl (Tyto furcata pratincola), and their origin, courses, and insertion were traced. In the head-neck region nine superficial larger cervical muscles of the craniocervical, dorsal and ventral subsystems were selected for analysis, and the muscle attachment sites were illustrated in digital models of the skull and cervical vertebrae of the same species as well as visualised in a two-dimensional sketch. In addition, fibre orientation and lengths of the muscles and the nature (fleshy or tendinous) of the attachment sites were determined. Myological data from this study were combined with osteological data of the same species. This improved the anatomical description of the cervical region of this species. The myological description provided in this study is to our best knowledge the most detailed documentation of the cervical muscles in a strigiform species presented so far. Our results show useful information for researchers in the field of functional anatomy, biomechanical modelling and for evolutionary and comparative studies.