Topic:Anatomy
Anatomy in horses encompasses the study of the structural organization of the equine body, including the bones, muscles, organs, and systems that function together to sustain life and enable movement. Understanding equine anatomy is important for veterinarians, equine scientists, and horse owners, as it provides insights into how horses move, how they respond to external stimuli, and how various conditions can affect their health and performance. Key anatomical features in horses include the musculoskeletal system, which provides support and locomotion; the cardiovascular system, which circulates blood and nutrients; and the respiratory system, which facilitates gas exchange. This page compiles peer-reviewed research studies and scholarly articles that explore the detailed anatomy of horses, focusing on the structure and function of different body systems, their interrelationships, and their relevance to equine health, performance, and veterinary care.
Treatment of shoulder joint luxation with glenoid ostectomy in a miniature donkey. A 13-year-old 128-kg miniature donkey gelding was evaluated for right forelimb lameness of 7 weeks' duration. Muscular atrophy of the infraspinatus and supraspinatus muscles over the right scapula with a palpable bony prominence over the point of the shoulder was evident. At the walk, the cranial phase of the stride was reduced with adduction of the distal aspect of the limb, dragging of the toe, and lameness (grade, 4/5). Lateral and craniocaudal radiographs of the right shoulder joint revealed lateral luxation of the humerus in relation to the scapula with bony proliferation and remodeling o...
Single-cut osteotomy for correction of a complex multiplanar deformity of the radius in a Shetland pony foal. To describe the surgical correction of a multiplanar deformity of the radius in a pony using a single-cut osteotomy. Methods: Case report. Methods: A 9-week-old male Shetland pony foal with a bodyweight of 47 kg. Methods: The foal presented with a complex multiplanar deformity of the right radius. A 3-dimensional model of the bone was created based on computed tomography (CT) imaging. To correct the deformity, the cutting plane for a single-cut osteotomy was calculated following the mathematical approach described by Sangeorzan et al. After osteotomy, the bone was realigned and stabilized wi...
Sequential Cerebrospinal Fluid Sampling in Horses: Comparison of Sampling Times and Two Different Collection Sites. Analysis of the cerebrospinal fluid (CSF) is important as a complementary test in horses with neurologic diseases, and sequential analysis may provide information about the treatment response or evolution and quantitative measures of the CSF drug concentration during treatment. The aim of this study was to compare erythrocyte and nucleated cell counts and protein concentration in multiple CSF samples obtained sequentially from two different puncture sites in clinically healthy horses. Eight and 12 horses, with no evidence of neurologic disease, were subjected to CSF collection from the atlanto...
Radiographic and CT features of zygomatic arch pneumatization in a Thoroughbred with a recurrent progressive ethmoid hematoma. A 7-year-old Thoroughbred gelding presented with a history of mild unilateral right-sided epistaxis and facial swelling over the right caudal maxillary sinus and zygomatic arch. Eleven months previously a progressive ethmoid hematoma had been surgically removed from the right caudal maxillary and conchofrontal sinus. Computed tomography identified a large expansile soft-tissue attenuating mass in the right caudal maxillary sinus, with protrusion into the conchofrontal sinus, that extended into the zygomatic arch. Lytic expansion and thinning of the cortex with pneumatization of the zygomatic a...
Maxillary Dentigerous Cyst with Double Wolf Teeth in a 3-Year-Old Quarter Horse Mare. Dentigerous cysts are characterised by the formation of cysts containing dental material with a variable level of development. They are the result of a distinct embryological phenomenon. Usually, they are of significant clinical relevance in horses, especially in tandem with ectopic tooth. Contrarily, supernumerary teeth or typical polyodontias usually have limited impact. In this case report, we describe the occurrence of a supernumerary first premolar (Triadan 105). Dissimilar to known scientific literature however was the formation of a cystic structure around the supernumerary tooth. Surgi...
The primary visual cortex of Cetartiodactyls: organization, cytoarchitectonics and comparison with perissodactyls and primates. Cetartiodactyls include terrestrial and marine species, all generally endowed with a comparatively lateral position of their eyes and a relatively limited binocular field of vision. To this day, our understanding of the visual system in mammals beyond the few studied animal models remains limited. In the present study, we examined the primary visual cortex of Cetartiodactyls that live on land (sheep, Père David deer, giraffe); in the sea (bottlenose dolphin, Risso's dolphin, long-finned pilot whale, Cuvier's beaked whale, sperm whale and fin whale); or in an amphibious environment (hippopotam...
Morphological differentiation of bovine and equine hair for species’ identification in forensic veterinary investigations. In this paper a morphological differentiation tool of bovine and equine hair for their identification in forensic investigations is provided. 30 animals were used, fifteen adult bovines of the "Siboney de Cuba" breed and fifteen adult equines of the "Criolla" breed. These species are the most bred in Cuba and, at the same time, the most exposed to poaching and theft crimes. Hair from the cows was sampled from the dorsal region, the lateral region and the ventral region; on the other hand, the horses' hair was sampled from the dorsal region of the body, of the mane and of the tail. The sampled ...
Neurovascular variations in the proximal plantar metatarsal region of the horse. Neurovascular variation may be relevant when performing surgical techniques to the proximal plantar metatarsal region. Objective: To document variations in the neurovascular anatomy of the proximal plantar metatarsal region and study the relationship of the neurovascular components to each other and other structures located in this area. Methods: Descriptive anatomical study. Methods: Paired cadaver hind limbs from 15 horses were dissected from the distal tibia to the metatarsophalangeal joint. Deep branch of the lateral plantar nerve (DBLPN) length, location of its origin from the lateral pla...
Toe white line separation associated with the notch (crena marginalis) on the distal phalanges in Thoroughbred yearling horses. The shape of the white line of the hoof is closely related to the shape of the notch on the dorsal distal bearing border of the distal phalanx (P3). In this study, a radiographic survey of the P3 of both forelimbs of 163 Thoroughbred yearling horses was conducted. The correlation of the depth and width of the notch were analyzed with the toe white line separation grades (0 to 3). As a result, the toe white line separation grade increased, the depth and the width of the notch also increased significantly. Radiographic examination of the P3 of the forelimbs might be useful for deciding whether t...
An Alternate Radiographic Guided Technique for Injection of the Equine Navicular Bursa Using a 40 mm (1.5-inch) 20-Gauge Needle: A Pilot Study. Injection of the equine navicular bursa can be technically challenging, and inadvertent penetration of other synovial structures is common using previously described techniques. When injecting the navicular bursa, inadvertent penetration of other synovial structures and hoof configuration can affect success rate, especially when performed by inexperienced operators. The aim of this study is to describe an alternate radiographic guided technique for injection of the equine navicular bursa that consistently avoids penetration of the distal interphalangeal joint using a 40 mm (1.5-inch) 20-gauge ...
Surface topography as a tool to detect early changes in a posttraumatic equine model of osteoarthritis. The equine model of posttraumatic osteoarthritis (OA) mimics certain aspects of the naturally occurring disease, both in horses and humans. The objective of this study was to assess articular cartilage degeneration in a posttraumatic OA model using the established macroscopic and microscopic scoring systems and compare them with a novel surface topography analysis. OA was induced in the carpal joint of 15 (n = 15) mixed breed horses. Surface changes on the articular cartilage were characterized using osteochondral blocks from the third carpal bone (C3) and radial carpal bone using surface...
Fracture Resistance of Equine Cheek Teeth With and Without Occlusal Fissures: A Standardized ex vivo Model. fracture models are frequently used in human dentistry to provide insights in the fracture mechanisms of teeth. Equine cheek teeth fractures are an important dental pathology, but there has been no research performed to examine the fracture resistance . To evaluate the fracture resistance of equine cheek teeth and identify anatomical predictors that might influence fracture resistance in healthy teeth. It was further evaluated if the presence of a fissure caused a decrease in fracture resistance. experimental design. Individual cheek teeth were subjected to a compression load in a univer...
Cartilage Degeneration of the Metacarpal Condyle and Enthesopaties of The Collateral Ligaments of Equine Metacarpophalangeal Joint. Articular degeneration can be characterized by fibrillation and eburnation of the articular layers of the metacarpophalangeal (MP) joint. Structural changes within the articular joint predispose the development of osteophytes, enthesophytes and, in many cases is associated with changes the collateral ligaments of the MP joint. The aim of the present study was to investigate the relationship between degenerative processes of the articular cartilage and the enthesopathies of collateral ligaments (superficial or deep portion) of the equine MP joint, using radiographic, ultrasonographic and anatom...
The influence of equine limb conformation on the biomechanical responses of the hoof: An in vivo and finite element study. Hoof conformation plays a key role in equine locomotion. Toe-in conformation is an abnormal condition characterized by inward deviation of the limb from its frontal axis. Several studies have documented differences in hoof deformation and hoof kinematics in horses with toe-in and normal hoof conformations. However, the reason behind this has yet to be understood. The present study hypothesizes that a different center of pressure (COP) path underneath the hoof is the cause of different deformation patterns and hoof kinematics in toe-in hooves. In vivo measurements and finite element (FE) analys...
Applied anatomy of the skull in the Arabian horse: A computed tomographic, cross-sectional, volumetric and morphometric study. This study was conducted to present a comprehensive and integrative computed tomography (CT) - anatomical cross sections atlas of skull, volumetric properties of the paranasal sinuses, and morphometric values for surface cranial nerves in the adult Arabian horse. Ten heads of Arabian horse breed were used. The different structures in the nasal, oral and cranial cavities were determined and labelled in the anatomical sections and their corresponding CT scan images. Three paranasal sinuses namely maxillary, conchofrontal and sphenopalatine sinuses were identified in the CT scan images. The cauda...
Cellular distribution of cannabinoid-related receptors TRPV1, PPAR-gamma, GPR55 and GPR3 in the equine cervical dorsal root ganglia. The activation of cannabinoid and cannabinoid-related receptors by endogenous, plant-derived or synthetic cannabinoids may exert beneficial effects on pain perception. Of the cannabinoids contained in Cannabis sativa, cannabidiol (CBD) does not produce psychotropic effects and seems to represent a molecule having great therapeutic potential. Cannabidiol acts on a great number of cannabinoid and cannabinoid-related G-protein-coupled receptors and ionotropic receptors which have, to date, been understudied in veterinary medicine particularly in equine medicine. Objective: To localise the cellula...
The Effect of Reducing the Bone to Cast Distance in an Equine Transfixation Pin Cast: An Ex Vivo Biomechanical Study. The aim of this study was to evaluate the effect of reducing the bone to cast distance on the resistance of the pin to cyclic loading in equine transfixation pin casts. Methods: Eleven pairs of cadaveric equine third metacarpal bones were prepared and one 6.3/8.0 mm transfixation pin was placed in standard fashion 10 mm proximal to the distal physeal scar into each bone. One metacarpus of each pair was tested with a distance of 10 mm (10 mm group) and the contralateral metacarpus with a distance of 20 mm (20 mm group) between the outer cortex of the bone and the fixation of t...
Sexual Differentiation and Primordial Germ Cell Distribution in the Early Horse Fetus. It was the aim of this study to characterize the development of the gonads and genital ducts in the equine fetus around the time of sexual differentiation. This included the identification and localization of the primordial germ cell population. Equine fetuses between 45 and 60 days of gestation were evaluated using a combination of micro-computed tomography scanning, immunohistochemistry, and multiplex immunofluorescence. Fetal gonads increased in size 23-fold from 45 to 60 days of gestation, and an even greater increase was observed in the metanephros volume. Signs of mesonephros atrophy wer...
Assessment of Functional Conservative Treatment of Acute Complete Achilles Tendon Rupture. In recent years, treatment for Achilles tendon rupture (ATR) went through radical changes: from the conservative non-weight bearing approach to a functional protocol. This functional protocol allows complete weight bearing after only 2 weeks by placing the foot in a plastic boot in tapered down equines and using interchangeable wedges under the heel. This change of approach has dramatically lowered the rate of re-rupture. Objective: To describe our preliminary results with this functional protocol and to assess outcome measures in the functional conservative treatment. Methods: The study compr...
Split Cord Malformation in a Thoroughbred Horse. We report a 9-year-old Thoroughbred gelding that had sudden onset lameness of the right forelimb with episodes of lateral decubitus and generalized pain after completion of a normal training session. The clinical signs subsequently became less pronounced with only mild right forelimb lameness. However, after further orthopaedic examination, it developed severe, acute ataxia and paraplegia, the Schiff-Sherrington phenomenon and risus sardonicus. At necropsy, a partial duplication of the cervical spinal cord was identified, consistent with split spinal cord malformation type II or diplomyelia. H...
Magnetic Resonance Imaging Findings of the Proximal Metacarpal Region in Warmblood Horses: 36 Lame and 26 Control Limbs (2015-2021). This study aims to evaluate the distribution and severity of bone and soft tissue lesions in the proximal metacarpal region of warmblood horses in lame and control groups. Correlation between lesions and ability to return to work was evaluated in the lame group. This restrospective analysis evaluated 62 horses with MRI examination of the proximal metacarpal region between Sept 2015 and Feb 2021. There were 36 lame limbs and 26 control limbs. The control group included seven contralateral limbs. Proximal suspensory ligament (PSL) size was not different between the lame and control groups. Hy...
A study of the shoulder and elbow joints of the donkey (Equus asinus) by gross anatomical dissection, radiography, computed tomography, and intra-articular injection. Joint diseases often represent the major part of equine clinician's caseloads. The current study aimed to document the normal anatomy of the donkey shoulder and elbow joints using computed tomography, cadaver sections, and radiography. Seven adult donkeys were used in this study. The current study proved there were no pouches of the donkey shoulder joint. Communication between the joint capsule and bicipital bursa was observed only in two limbs of four used in the present work. The joint was without pericapsular ligaments. The glenohumeral ligament was identified by the thickening of the artic...
No modularity at ventral level in the horse skull. Morphological integration and modularity are concepts that refer to the covariation level between the components of a structure. Morphological modules are independent subsets of highly correlated traits. The horse skull has been studied as a whole functional structure for decades, but the integrative approach towards quantitative examination of modules is scarce. We report here the first evaluation of cranial modularity in the horse at basal level. For this, we studied the modularity hypothesis for splanchnocranium and basicranium modules in the horse, two phenotipic regions under local influe...
Cryotherapy provides transient analgesia in an induced lameness model in horses. The analgesic effect of cryotherapy in an induced lameness model was evaluated. Lameness was induced with solar pressure from a custom-made shoe in a 10-horse, cross-over study. The degree of lameness was recorded with a commercial non-invasive inertial sensor. The distal limbs were maintained in an ice and water slurry (cryotherapy) or at ambient temperature (control) for 1 hour. Lameness was assessed serially over the following hour. Lameness at each time point was compared to the baseline induced lameness, within and between groups. Lameness had improved significantly in all horses 5 minute...
Assessment of qualitative and quantitative parameters of healthy thyroid gland in adult horses by magnetic resonance imaging. In humans and pets, magnetic resonance imaging (MRI) provides important adjunctive anatomic information about the thyroid and its adjacent structures. To the best of our knowledge, however, no studies have been reported regarding the use of MRI for thyroid evaluation in horses. The aim of this study was to obtain qualitative and quantitative parameters of healthy thyroid gland in adult horses by MRI. Eleven horses were submitted to thyroid MRI evaluation. The healthy thyroid of these animals was ensured by normal examinations performed before (free thyroxine and ultrasound) and after (cytology...
Microstructural features of subchondral radiolucent lesions in the medial femoral condyle of juvenile Thoroughbreds: A microcomputed tomography and histological analysis. The aetiology of equine medial femoral condyle (MFC) subchondral bone radiolucencies (SR) is unknown. Objective: Characterise the microstructural structural features of MFC SR in juvenile Thoroughbreds with microcomputed tomography (μCT) and histology. Methods: Cross-sectional post-mortem study. Methods: Distal femurs were collected at post-mortem. Conventional tomodensitometry was employed to scout for MFCs with and without SR lesions (SR+ and SR-, respectively). Group 1 were CT MFC SR+ and Group 2 age-matched SR- controls. Both underwent μCT and histological analysis. Group 3 CT MFC SR- fo...
Evaluation of the airway mechanics of modified toggle laryngoplasty constructs using a vacuum chamber airflow model. To evaluate the airway mechanics of modified toggle LP constructs in an airflow chamber model and compare these to the airway mechanics of standard LP constructs. Methods: Ex-vivo experimental study. Methods: Fifty-one equine cadaveric larynges. Methods: Bilateral LP constructs were performed using a modified toggle (n = 23) or a standard (n = 21) LP technique. Constructs were tested in an airflow model before and after cyclic loading which was designed to mimic postoperative swallowing. The cross-sectional area (CSA), peak translaryngeal airflow (L/s), and impedance (cmH 0/L/s) were deter...
Radiogrametric Analysis of the Thoracic Limb Phalanges in Arabian Horses and Thoroughbred Horses. In this study, it was aimed to determine the statistical differences between Arabian horses and Thoroughbred horses based on X-ray images of forelimb digital bones. Latero-medial X-ray images of digital bones of thoracic limbs were taken of 25 Arabian horses and 50 Thoroughbred healthy horses. The difference between males and females within the breed was statistically analyzed as well. Nine measurements and three indexes taken from phalanges of thoracic limbs were used. Thoroughbred horses did not differ significantly between sexes, as indicated by the ANOVA. For the Arabian horses, the length...
RNA sequencing and immunofluorescence of the myotendinous junction of mature horses and humans. The myotendinous junction (MTJ) is a specialized interface for transmitting high forces between the muscle and tendon and yet the MTJ is a common site of strain injury with a high recurrence rate. The aim of this study was to identify previously unknown MTJ components in mature animals and humans. Samples were obtained from the superficial digital flexor (SDF) muscle-tendon interface of 20 horses, and the tissue was separated through a sequential cryosectioning approach into muscle, MTJ (muscle tissue enriched in myofiber tips attached to the tendon), and tendon fractions. RT-PCR was performed...
Use of cone-beam computed tomography for advanced imaging of the equine patient. Access to volumetric imaging modalities, such as magnetic resonance imaging (MRI) and computed tomography (CT), has increased over the past decade and has revolutionised the way clinicians evaluate equine anatomy. More recent advancements have resulted in the development of multiple commercially available cone-beam CT (CBCT) scanners for equine use. CBCT scanners modify the traditional fan-shaped beam of ionising radiation into a three-dimensional pyramidal- or cone-shaped beam of radiation. This modification enables the scanner to acquire sufficient data to create diagnostic images of a regio...