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.
The effect of manually facilitated flexion of the thoracic spine on the interspinous space among horses with impinging dorsal spinous processes of the thoracic vertebrae. Impinging dorsal spinous processes (IDSP) are typically diagnosed and graded using radiography, during which the effect of the horses' thoracolumbar posture on the interspinous spaces is not commonly considered. Posture can be altered from a spontaneous, relatively extended, or lordotic, position by manual facilitation of thoracic flexion ('thoracic lift'). This study aimed to ascertain if the thoracic vertebral interspinous space distances were increased by using facilitated thoracic flexion to alter the posture in horses diagnosed with IDSP. Seven horses of mixed breed and sex, median age 9....
Evaluation of locking compression plate fixation of the distal phalanx to the hoof wall as a potential therapy for laminitis. Surgical stabilisation of the distal phalanx (DP) is a potential therapeutic strategy for severe acute laminitis. Objective: To evaluate the effects of locking compression plate (LCP) fixation of the DP to the dorsal hoof wall. Methods: Ex vivo and in vivo experiments. Methods: A T-shaped LCP was applied to one limb per pair in six pairs of cadaver forelimbs subjected to a combination of thermally induced lamellar failure and vertical load to simulate severe acute laminitis. Standard radiographic measurements were used to compare DP displacement. The LCP was then applied to one forefoot in 12 ...
Investigating the reliability of metapodials as taxonomic Indicators for Beringian horses. The metapodials of extinct horses have long been regarded as one of the most useful skeletal elements to determine taxonomic identity. However, recent research on both extant and extinct horses has revealed the possibility for plasticity in metapodial morphology, leading to notable variability within taxa. This calls into question the reliability of metapodials in species identification, particularly for species identified from fragmentary remains. Here, we use ten measurements of metapodials from 203 specimens of four Pleistocene horse species from eastern Beringia to test whether there are s...
Videodermoscopic examination of the skin and its products in purebred Arabian horses in the summer season. Videodermoscopy is a method that enables the examination of many parameters of the skin and its structures. The aim of this study was to assess specific dermoscopic parameters in purebred Arabian horses during the summer. The study involved 21 clinically healthy purebred Arabian horses (18 mares and three stallions) that had not been used for breeding and were 1 to 25 years old. The videoderoscopic evaluation was performed on seven selected areas of the body: forehead, mane, neck, chest, flank, rump, and tail. The tests were carried out with Vidix and Olympus cellSens specialised software. Vid...
B-mode and color Doppler ultrasonography of normal external jugular vein in donkeys (Equus asinus). Although the jugular vein is a major important blood vessel in equine, the literature lacks this vessel's normal B-mode and Doppler ultrasonographic examinations in donkeys. Therefore, this study aimed to determine the reference ranges of B-mode and Doppler ultrasonographic indices of jugular veins in healthy adult donkeys (Equus asinus) and the possible effect of examination side (left and right), gender, and body condition on the ultrasonographic measurements of this vessel. B-mode and Doppler ultrasound imaging of the external jugular vein was conducted on 20 adult healthy donkeys of both s...
Tongue ties do not widen the upper airways in racehorses. There is contradictory evidence on the potential benefits of tongue ties on upper airway function and their efficacy in inhibiting intermittent dorsal displacement of the soft palate (DDSP) in racehorses. Objective: To test the hypothesis that tongue ties increase the pharyngeal diameter and decrease the occurrence of dynamic airway obstruction in racehorses. Methods: Prospective, crossover blinded clinical study. Methods: Data of 22 Thoroughbred and 8 Standardbred racehorses examined using overground endoscopy under full-intensity exercise on training racetracks with and without fixation of t...
A method to identify, dissect and stain equine neuromuscular junctions for morphological analysis. Morphological study of the neuromuscular junction (NMJ), a specialised peripheral synapse formed between a lower motor neuron and skeletal muscle fibre, has significantly contributed to the understanding of synaptic biology and neuromuscular disease pathogenesis. Rodent NMJs are readily accessible, and research into conditions such as amyotrophic lateral sclerosis (ALS), Charcot-Marie-Tooth disease (CMT), and spinal muscular atrophy (SMA) has relied heavily on experimental work in these small mammals. However, given that nerve length dependency is an important feature of many peripheral neurop...
Combined Antenna-Channel Modeling for the Harsh Horse Hoof Environment. This paper describes the exploration of the combined antenna-channel model for a horse hoof. An antenna of 25 mm × 40 mm is designed in the ISM 868 MHz band. During the characterization and design of the antenna, the dynamic and harsh environment of the horse hoof is taken into account throughout every step of the procedure because it is impossible to de-embed the antenna from its environment. The antenna and channel model are verified extensively by measurements in phantom and ex vivo. The antenna is verified to be robust against changes in the morphology of the horse's hoof up to 50%. The d...
Ex vivo and in vivo evaluation of a modified interrupted Lembert pattern for small intestinal anastomoses in horses. To compare single-layer anastomoses (modified continuous Lembert [mod-CL] and modified-interrupted Lembert [mod-IL]) and a 2-layer simple continuous anastomosis (2 L; seromuscular and mucosal) for jejunojejunal anastomoses in equine cadavers and to compare ex vivo to in vivo time to complete the anastomosis and stoma size with a mod-IL pattern. Methods: Measurements in jejunum from cadaver and anesthetized horses. Methods: Ten live horses and 18 equine cadavers. Methods: Time to complete anastomosis, bursting pressures (BP), leakage sites, and anastomotic index (size ratio of anastomotic lume...
Intra- and Interexaminer Measurement Variability Analysis of an Orthodontic Gauge Device to Determine Incisor Occlusal Surface Angles in the Horse. Incisor malocclusions are common in horses. As yet, an evidence-based understanding of incisor occlusal surface angle dynamics and normocclusal range is missing. Orthodontic measuring devices could help unravel this information objectively but imply measurement validation. We evaluated intra- and interexaminer variability of repeated sagittal and transversal incisor occlusal surface angle measures using a commercial orthodontic gauge device (). Five examiners (two experienced, three inexperienced) measured six cadaver heads on 2 consecutive days in a blinded block-randomization design, resulti...
Ex-vivo articular cartilage removal from equine proximal interphalangeal joints using cannulated drill bits. This report evaluates the use of 4.5- and 5.5-mm cannulated drill bits for articular cartilage removal from the proximal interphalangeal joints of equine cadaver limbs. Limbs from 8 equine cadavers, all with normal proximal interphalangeal joints. Proximal interphalangeal joints of 32 limbs from 8 equine cadavers were drilled using either 4.5- or 5.5-mm cannulated drill bits. Pastern joints were then disarticulated, and intra-articular drilling was evaluated by visual inspection. Post-drilling evaluation revealed complete intra-articular drilling occurred in all 32 joints. Canulated 4.5- and 5...
CT measures of osseous cervicothoracic intervertebral foramina are repeatable and associated with CT measures of adjacent articular processes in horses. Narrowing of the equine cervicothoracic intervertebral foramina (IF) has the potential to cause forelimb lameness and/or neck pain although limited information is available on CT of the IF. The aims of this retrospective, analytical study were to describe a protocol for quantifying CT cervicothoracic IF size; evaluate the repeatability of IF size measures; test associations between IF size and adjacent articular process (AP) size, ventral extent, and anatomic location; and determine the proportion of IF with narrowing. Computed tomographic images were acquired in 20 Warmblood horses that prese...
Study on ultrasonic wave propagation in equine leg bone for screening bucked shin. For simple, safe, portable, and inexpensive evaluation suitable for leg bone diseases of racehorses in the field, an ultrasonic measurement technique was applied to evaluate wave velocities. A digital model of the third metacarpal bone with the bucked shin was fabricated using high-resolution peripheral quantitative computerized tomography data of a racehorse. This model was anisotropic and heterogeneous, and was constructed using the measured ultrasonic wave velocities in the bone. With this model, ultrasonic wave propagation along the bone axis was simulated using the elastic finite-differen...
Computed tomographic arthrography, gross anatomy and histology demonstrate a communication between synovial invaginations in the proximal aspect of the third interosseous muscle and the carpometacarpal joint in horses. This descriptive anatomical study investigates the relationship between the third interosseous muscle, also known as the suspensory ligament, and the carpometacarpal joint in forelimbs of horses, with the hypothesis that there was a direct synovial communication between these structures as shown by computed tomographic arthrography, histology, and gross anatomy sections. Computed tomography of the carpus and metacarpal region was performed on two groups. Group 1 consisted of eight cadaver limbs undergoing computed tomographic arthrography following injection of a mixture of positive contrast m...
Equine skeletal scintigraphy: Comparing normal bone-to-soft tissue ratio 2 and 4 hours after injection with either hydroxymethylene diphosphonate or methylene diphosphonate. In equine skeletal scintigraphy, there is no information about the possible influence of different phosphonate compounds on image quality. This prospective randomised study determined bone uptake changes and image quality for hydroxymethylene diphosphonate (HDP) and methylene diphosphonate (MDP) in equine patients at different time points. Scintigraphic images of the radius and the tibia of 20 horses were acquired at 2 and 4 hours after injection of either technetium-labelled HDP or MDP. Three regions of interest were identified-in the bone diaphysis, adjacent soft tissue and background area-t...
Clinical, Diagnostic and Histological Findings Involving Cheek Teeth Hypercementosis in Nine Horses. Hypercementosis is infrequently reported to affect the cheek teeth of horses and presents as mineral deposits either attached (peripheral) or solitary ovoid (nodular) structures in the tooth bearing region. There is overlap between radiological and histological appearance of hypercementosis, cementoma, and equine odontoclastic tooth resorption and hypercementosis (EOTRH). The clinical presentation, imaging features, surgical management, and histological findings of nine horses that presented for dental lesions and associated hypercementosis of cheek teeth are reported. Horses were 4-15 years o...
Equine hoof wall: Structure, properties, and bioinspired designs. The horse hoof wall exhibits exceptional impact resistance and fracture control due to its unique hierarchical structure which contains tubular, lamellar, and gradient configurations. In this study, structural characterization of the hoof wall was performed revealing features previously unknown. Prominent among them are tubule bridges, which are imaged and quantified. The hydration-dependent viscoelasticity of the hoof wall is described by a simplified Maxwell-Weichert model with two characteristic relaxation times corresponding to nanoscale and mesoscale features. Creep and relaxation tests r...
Effectiveness of a Student-Developed Instructional Video in Learning the Anatomy of the Equine Distal Limb. The anatomy of the equine distal limb (EDL) is both complex and important to veterinary clinical practice. First-year veterinary students (VM1s) often struggle to adequately understand it. Two third-year veterinary students collaborated with instructors to create an instructional video to facilitate first-year students' comprehension of EDL anatomy. The video was offered to all VM1s. Learning outcomes were assessed via practical exams. Exam scores on EDL structures were compared between students who did () and students who did not () watch the video. Students' laboratory experiences and confid...
Pulmonary bleeding in racehorses: A gross, histologic, and ultrastructural comparison of exercise-induced pulmonary hemorrhage and exercise-associated fatal pulmonary hemorrhage. Exercise-induced pulmonary hemorrhage (EIPH) is a common condition of Thoroughbred racehorses that is usually responsible for reduced performance, while exercise-associated fatal pulmonary hemorrhage (EAFPH) is characterized by severe pulmonary bleeding of unknown pathogenesis resulting in sudden death during strenuous exercise. The aim of the study was to characterize and compare anamnestic data together with pulmonary gross, histologic, and ultrastructural findings in racehorses with EIPH (n = 10), EAFPH (n = 10), and control horses (n = 5). No differences in anamnesis were identified betwee...
Alterations to the synovial invaginations of the navicular bone are associated with pathology of both the navicular apparatus and distal interphalangeal joint when evaluated using high field MRI. Limited information exists regarding associations between distal interphalangeal joint (DIPJ) abnormalities and synovial invagination changes in the distal sesamoid (navicular) bone. This retrospective, analytical study aimed to measure specific characteristics of the synovial invaginations of the navicular bone to determine whether any single characteristic was associated with abnormalities in the DIPJ or navicular apparatus (NA) using high field MRI and a sample of 200 horses' feet. The DIPJ and NA were graded independently by three scorers. The grades were averaged, creating a global pathol...
Neurological Examination of Horses. The neurological examination is undertaken to determine whether any deficit is due to a lesion in the nervous system and, if so, where within the nervous system any possible lesion or lesions are located. The examination of horses has challenges not encountered when doing the equivalent examination in dogs and cats, principally that spinal reflexes and postural reactions are impossible/difficult to assess in most animals. The anatomy book can be consulted later but at the end of the neurological examination the clinician then should be able to determine broadly which area of the neuromuscular ...
Sex differences in cervical spinal cord and spinal canal development in Thoroughbred horses. Cervical vertebral stenotic myelopathy (CVSM), a common cause of cervical spinal cord compression, is a neurological disease characterized by general proprioceptive ataxia and weakness of hindlimbs that tends to develop in young adult Thoroughbred horses. Although male horses seem to be at increased risk for CVSM, the mechanism for the occurrence of sex differences in the prevalence of CVSM is still poorly understood. Hence, we hypothesized that sex differences in the development of cervical spinal cord and spinal canal would affect the development of CVSM. This study aimed to evaluate sex dif...
Laryngeal reinnervation using the spinal accessory nerve: Electromyographic study of the sternomandibularis muscle. Selective laryngeal reinnervation using the first and second cervical nerve (C1C2) is a treatment option for recurrent laryngeal neuropathy that aims to restore the function of the cricoarytenoideus dorsalis (CAD) muscle. Despite the technique's satisfying success rate, it has several limitations. These triggered the search for another potential donor nerve that could reduce CAD muscle fatigue and shorten rehabilitation. The ventral branch of the spinal accessory nerve, providing motor innervation to the sternomandibularis (SM) muscle, was identified as a potentially well-adapted nerve. Object...
Precision of cyathostomin luminal worm counts: Investigation of storage duration and fixative. Essentially all grazing horses are infected with cyathostomin parasites. Adult cyathostomins reside in the large intestine of the horse and larval stages encyst within intestinal mucosa. Manual worm collection from aliquots of intestinal content is the current gold standard for retrieval and enumeration of luminal parasites, however, no research has been conducted to standardize specific parameters for processing and storage of samples. The aims of this study were (1) to evaluate the precision of current standard operating procedures for enumeration of luminal adult cyathostomin populations, (...
Ultrasonographic diagnosis of femoral fractures in large animals. Femoral fractures are often catastrophic in large animals. Radiographic diagnosis is limited by patient size and feasibility, especially in ambulatory settings. Ultrasonography is widely available and may provide an alternative to radiography for definitive diagnosis. 12 large animals (6 horses, 5 cattle, and 1 elephant). Retrospective analysis of large animal patients diagnosed with femoral fracture by use of femoropelvic ultrasonography (2000 to 2019). 5 of 12 cases were ≤ 1 year of age. The remaining 7 cases were 2 to 33 years of age (median, 13 years). All patients developed severe acute...
Palmar/plantar oblique projections improve radiographic detection of fractures of the palmar/plantar processes of the equine distal phalanx. Radiography is a standard diagnostic test for horses with suspected fractures of the palmar/plantar processes (PP) of the distal phalanx, however published studies evaluating the diagnostic utility for radiography are currently lacking. The objectives of this retrospective, diagnostic case-control study were to determine the sensitivity of radiographs for the detection of PP fractures, and determine the diagnostic utility of the palmar/plantar oblique projections of the PP for the identification of PP fractures compared to standard radiographic series. The medical records of horses undergoing...
Standardized uptake values and attenuation correction in 18 F-sodium fluoride PET of the equine foot and fetlock. Maximal standardized uptake values (SUV ) are commonly used for the interpretation of PET studies. Limited information regarding the SUV of F-NaF PET in horses is currently available in the literature. The goals of this retrospective secondary analysis study were to provide reference values for F-NaF SUV in the equine distal extremity and assess the effect of attenuation correction. Nonattenuation corrected (NAC) and CT-based attenuation corrected (CTAC) SUV were obtained from 19 feet and 19 fetlocks. Twenty regions of interest (ROIs) were defined for the foot and 22 for the fetlock. Areas p...
Relationship between anatomical characteristics and personality traits in Lipizzan horses. We tested 35 Lipizzan horses older than 5 years, ridden and healthy in three behavioural tests (handling, fear-reaction, and target training test). Physiological (heart rate and heart rate variability) and anatomical measurements (120 head and body distances and angles) were collected to validate parameters that reliably inform on handling/cooperation, fear/exploration and trainability in horses. Utilizing a standard clustering methodology on the behavioural data, we identified four general types of responses and categorised an individual as intermediate, low fearful, horses with low cooperati...
Structure and Strength of Bovine and Equine Amniotic Membrane. Thin, strong scaffold materials are needed for surgical applications. New materials are required, particularly those readily available, such as from non-human sources. Bovine amniotic membrane (antepartum) and equine amniotic membrane (postpartum) were characterized with tear and tensile tests. The structural arrangement of the collagen fibrils was determined by small-angle X-ray scattering, scanning electron microscopy, and ultrasonic imaging. Bovine amnion had a thickness-normalized tear strength of 12.6 (3.8) N/mm, while equine amnion was 14.8 (5.3) N/mm. SAXS analysis of the collagen fibri...