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.
Cone-beam computed tomography of the head in standing equids. Computed tomography in standing horses has revolutionized diagnostic imaging. The O-arm®, a cone beam computed tomography (CBCT) scanner with a gantry opening of 96.5 cm is routinely used for image-guided spine and neurosurgery in humans. The aim of this study is to describe the set-up and first experiences using the O-arm® to achieve CBCT imaging of the head in standing horses. CT imaging of the predefined region of interest (ROI) was tested on 2 cadaveric heads, concentrating on centering issues within the gantry, as well as determining the number of scans needed per ROI. All horses pres...
A comparative multi-site and whole-body assessment of fascia in the horse and dog: a detailed histological investigation. Fascia in the veterinary sciences is drawing attention, such that physiotherapists and animal practitioners are now applying techniques based on the concept of fascia studies in humans. A comprehensive study of fascia is therefore needed in animals to understand the arrangement of the fascial layers in an unguligrade horse and a digitigrade dog. This study has examined the difference between the horse and the dog fascia at specific regions, in terms of histology, and has compared it with the human model. Histological examinations show that in general the fascia tissue of the horse exhibits a t...
Partial resection of bilateral ulnar remnants for treatment of carpus valgus in a 3-week-old Hanoverian foal. A 3-week old Hanoverian foal was presented with bilateral moderate to severe carpal valgus. The deviations were 10 and 14 degrees, respectively for the left and right carpi and orthogonal radiographs of both front limbs highlighted bilateral persistent ulnar remnants. A partial resection of the ulnar remnants and periosteal transection on the disto-lateral aspect of the radius were performed bilaterally under general anesthesia. The valgus deviations began to improve within the first month and the limbs were almost straight (2 degrees for the left and right carpi) 5 1/2 months after surgery. T...
Scintigraphic evaluation of cheek teeth in clinically sound horses. Dental disorders are one of the top-ranking clinical domains in equine practice. Scintigraphy has emerged as a useful diagnostic imaging modality for equine dental diseases. There is a paucity of the normal scintigraphic uptake and its correlation with age. This prospective, cross-sectional, descriptive and pilot-designed study aimed to describe the radioisotope uptake (RU) patterns of the reserved crown and periodontal bone of the maxillary and mandibular cheek teeth (CT) in clinically sound horses and to evaluate the age effect on RU. For this purpose, 60 horses that underwent a bone scintig...
An equine cadaver study investigating the relationship between cervical flexion, nuchal ligament elongation and pressure at the first and second cervical vertebra. Pressure in the atlanto-axial region due to hyperflexion ('rollkur') may influence the development of a nuchal bursa, as adventitious bursae may be caused by pressure. Investigating the pressure between the nuchal ligament and atlas/axis in a flexed position may provide information on the pathogenesis of nuchal bursitis. In this study, ten equine head and neck specimens with one side of the soft tissues over the cervical vertebral spine removed were placed in lateral recumbency on a table in neutral, mildly flexed, and hyperflexed head and neck positions. Angulations of the neck were measured ...
Computed Tomographic Evaluation of Adjacent Segment Motion after Ex Vivo Fusion of Equine Third and Fourth Cervical Vertebrae. Surgical fusion of vertebral segments is a treatment option for horses with cervical stenotic myelopathy or cervical fracture.Degenerative disease affecting adjacent vertebral segments is a reported complication following surgical vertebral fusion in other species, termed adjacent segment disease. The aim of this study was to evaluate the impact of cervical vertebral fusion on the biomechanics of adjacent vertebral segments in the horse. Methods: Neck specimens of 12 horses were assessed using computed tomographic imaging. Range of motion (ROM) was determined by measuring the maximum sag...
Various 3D printed materials mimic bone ultrasonographically: 3D printed models of the equine cervical articular process joints as a simulator for ultrasound guided intra-articular injections. In the equine racehorse industry, reduced athletic performance due to joint injury and lameness has been extensively reviewed. Intra-articular injections of glucocorticoids are routinely used to relieve pain and inflammation associated with osteoarthritis. Intra-articular injections of pharmaceutical agents require practice for precise needle placement and to minimize complications. Training on simulators or models is a viable alternative for developing these technical skills. The purpose of this study was to compare the qualitative ultrasonographic characteristics of three-dimensional (3D) pr...
Histological and morphometric study of the components of the sinus and atrioventricular nodes in horses and dogs. The cardiac nodes are the source of the electrical impulse that is transmitted to the heart, the aim of this work is study the histological and morphometric characteristics of the different components of the sinus and atrioventricular nodes in horses and dogs that help to know the physiopathology of these nodes. A group of ten horse hearts and five dog hearts were used. The region of the sinus and atrioventricular nodes was sectioned serially, and the block of tissue removed for study. The samples were assessed using a morphometric analysis with the Image-Pro Plus 7.1 software and the acquisit...
Anatomical variations of the equine popliteal tendon. The function of the popliteal muscle and tendon in horses remains undescribed. In humans, it is considered a stabilizer of the posterior-lateral region of the knee; its function is closely related to that of the lateral collateral ligament (LCL) and meniscus. The popliteal tendon (PopT) constitutes the main proximal attachment of the popliteus muscle to the femur, and in humans, insertional variations have been described. Knowledge of anatomical variations is needed for the correct interpretation of diagnostic images and arthroscopic findings. To elucidate further the anatomy of the equine Pop...
Equine cervical intervertebral disc degeneration is associated with location and MRI features. Morphology of the equine cervical intervertebral disc is different from that in humans and small companion animals and published imaging data are scarcely available. The objectives of this exploratory, methods comparison study were (a) to describe MRI features of macroscopically nondegenerated and degenerated intervertebral discs (b) to test associations between spinal location and macroscopic degeneration or MRI-detected annular protrusion and between MRI-detected annular protrusion and macroscopic degeneration, and (c) to define MRI sequences for characterizing equine cervical intervertebral...
Optimization of RNA extraction protocol for long-term archived formalin-fixed paraffin-embedded tissues of horses. A suitable RNA extraction protocol was established to gain high quality RNA from formalin-fixed paraffin-embedded tissues to perform reliable molecular assays either applicable for using FFPE tissue archives or tissues with harsh formalin-fixation. Eighteen FFPE samples from the central nervous system of horses, stored up to 11 years, were used as archive cases. To test the influence of the fixation period, brain, liver, kidney, and skeletal muscle tissue fragments from another horse, were treated either with water or tris-acetate-EDTA buffer after fixation under different timepoints with 10...
A study of residual lesions in horses that recovered from clinical signs of chronic equine dysautonomia. Equine dysautonomia (ED) causes degeneration and loss of autonomic neurons. Approximately 50% of chronic cases recover, but it is unclear how they survive neuronal loss. Objective: To assess lesions, autonomic neuron numbers, interstitial cells of Cajal (ICC), and neurodegeneration in recovered cases. Methods: Thirteen cases (group ED), euthanized 10.3 ± 5.2 (1-16) years from diagnosis and 6 age-matched controls (group C). Methods: Prospective, case control; routine post mortem examination, neuron counts in peripheral and enteric ganglia and immunohistochemical assessment of neural networ...
Ultrasonographic findings post laryngoplasty in the horse. Laryngoplasty is commonly used to treat laryngeal hemiplegia in Thoroughbred racehorses. Evaluation of the success of the laryngoplasty is traditionally determined using endoscopy. Laryngeal ultrasonography and normal ultrasonographic appearance have been reported in the standing horse, but post-laryngoplasty and ventriculectomy ultrasonographic evaluation has limited literature coverage. A prospective case series of 10 Thoroughbred racehorses with left laryngeal hemiplegia was examined ultrasonographically and endoscopically prior to 3-10 days, 30-50 days, and 6-12 months after laryngoplasty ...
Evaluation of four techniques for injection of the proximal interphalangeal joint in horses. To describe a dorsoproximal midline (DPM) standing technique for proximal interphalangeal joint (PIPJ) injection and to compare it to established dorsolateral flexed (DLF), palmaroproximal (PP), and dorsolateral standing (DLS) techniques. Methods: Ex vivo study. Methods: Sixty cadaver equine thoracic limbs. Methods: Limbs were divided into four groups (n = 15 each group), DLF, DPM, PP, and DLS. For each technique, three operators injected radiopaque contrast and methylene blue into the PIPJ in five limbs. The number of attempts required was recorded. Successful injection was confirmed by radio...
Investigation of changes in bone density and chemical composition associated with bone marrow oedema-type appearances in magnetic resonance images of the equine forelimb. The aetiology of bone marrow oedema-like abnormalities (BMOA) seen on magnetic resonance imaging (MRI) is as yet not fully understood. The current study aimed to investigate the potential of projection radiography and Raman microspectroscopy to provide information regarding the underlying physiological changes associated with BMOA in equine bone samples. Methods: MRI was used to assess 65 limbs from 43 horses. A subset of 13 limbs provided 25 samples, 8 with BMOA present and 17 as controls; these were examined with projection radiography to assess bone mineral density and Raman spectroscopy to...
Magnetic resonance dacryocystography in the horse: A feasibility study. To provide a comprehensive anatomical description of the normal equine nasolacrimal duct using magnetic resonance imaging, and to develop a practical protocol for performing magnetic resonance dacryocystography (MRD) in horses. Methods: The heads of ten fresh horse cadavers with no history of sinonasal or ophthalmologic disorders were used for this study. Methods: An MRD technique was developed in this study, which consisted of two parts. In the first part, olive oil and gadolinium were compared as contrast medium, using five horses. Two concentrations of gadolinium were used: 0.25 mmol/mL an...
Internal fixation of a complete ventral luxation of the dens axis in an American quarter horse yearling. To report surgical treatment of a complete luxation of the atlantoaxial articulation with a 4.5-mm T-locking compression plate (T-LCP) in a horse. Methods: Case report. Methods: A one-year-old American quarter horse filly. Methods: A one-year-old American quarter horse filly presented with a complete luxation of the atlantoaxial articulation. Closed and open reduction of the luxation were attempted under general anesthesia with the aid of a pulley system. Because the manual reduction was unsuccessful, the dens axis was excised, and the atlas and axis were stabilized with a 4.5-mm T-LCP. Fo...
Evaluation of the Structure of Myodural Bridges in an Equine Model of Ehlers-Danlos Syndromes. Myodural bridges have been described in various species as connective tissue structures "bridging" small cranio-cervical muscles to the dura. Myodural bridges are thought to stabilize the dural sac during head and neck movements and promote cerebrospinal fluid motion; however, their role in neurological diseases has not yet been established. We report ultrasonographic visualization, necropsy, histopathologic and ultrastructural findings of myodural bridges in horses with hereditary equine regional dermal asthenia (HERDA), an equine model of Ehlers-Danlos syndromes. Five HERDA and 5 control hor...
Comparative Stiffness of an Equine Distal Sesamoid Bone Fracture Model Stabilized with 3.5-mm versus 4.5-mm Cortical Bone Screws in Lag Fashion. The aim of this study was to to determine the comparative stiffness following repair of an axial sagittal fracture model in equine distal sesamoid bones using either a single 3.5-mm or 4.5-mm cortical bone screw placed in lag fashion. Methods: The present study was an biomechanical study. Results: The mean (±standard deviation) stiffness value for the 4.5-mm screw-bone construct (522.49 N/mm ± 168.21) was significantly greater than the 3.5-mm screw-bone construct (408.46 N/mm ± 131.13) ( = 0.047). This represents a 28% difference in mean stiffness. Conclusions: ...
Experimentally Induced Open Pneumothorax in Horses. The objective of this study was to evaluate clinical and cardiovascular parameters and pleural and intra-abdominal pressures of horses after experimentally induced unilateral open pneumothorax. Prospective, experimental study-animals: seven healthy adult horses, 4 females and 3 males. Left hemithorax thoracotomy was carried out to create an open pneumothorax for 60 minutes. Pleural pressure (P) was directly obtained at the midpoint of the left eighth intercostal space before thoracotomy. Esophageal pressure (P), arterial blood gas analysis, left ventricular function, and ultrasonographic asses...
The influence of trimming of the hoof wall on the damage of laminar tissue after loading: An in vitro study. Laminitis is associated with failure of the suspensory apparatus of the distal phalanx (SADP) connecting the distal phalanx to the hoof wall. The specific aim of this study was to examine in vitro whether thinning of the hoof wall leading to increased deformability influences the damage of the laminar tissue created by loading of the hoof. Paired cadaver forelimbs from twelve horses were used. For each pair, the hoof wall from one hoof was thinned by 25%; this was ascertained by radiography. The contralateral hooves were used as controls. In a material testing machine, hooves were loaded in a ...
Standing MRI for surgical planning of equine fracture repair. To report the feasibility of standing MRI (sMRI) and document the value of sMRI in surgical planning for surgical repair of limb fractures in the horse. Methods: Retrospective case series. Methods: Thirty-one horses with preoperative sMRI. Methods: Medical records were reviewed for fracture type, application of a polyester cast, sMRI sequences performed, technical variables, and image quality. Fracture geometry and concomitant lesions were compared between sMRI and radiography. The relative value of sMRI with regard to surgical planning was classified as minor (sMRI did not provide additional ...
Suspensory Branch Desmitis in a Horse: Ultrasonography, Computed Tomography, Magnetic Resonance Imaging, and Gross Postmortem Findings. Injury of suspensory ligament (SL) branch is a frequently diagnosed problem in horses of different ages and disciplines. This case reports for the first time the ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI) findings in a 10-year-old draught horse with traumatic chronic SL branch desmitis of 8 months duration. The horse had a grade 3 of 5 left hindlimb lameness with a moderately hot, painful, and diffuse swelling from the tarsus till the hoof. Ultrasonography, both SL branches appeared as enlarged hyperechogenic structures with poor demarcation of their margins a...
Donkey pericardium compares favorably with commercial xenopericardia used in the manufacture of transcatheter heart valves. Transcatheter aortic valve implantation (TAVI) has gained considerable acceptance in the past decade due to its lower risks than conventional open-heart surgery. However, the deformation and delamination of the leaflets during the crimping procedure have raised questions about the durability and long-term serviceability of the pericardium tissue from which the leaflets are made. The collagen architecture, wall thickness and mechanical properties of donkey pericardium were investigated to assess its suitability as an alternative material for the manufacture of heart valves. Coupons sampled from...
Pressuring of Acupoints as a Complement to the Diagnosis of Stifle Diseases in Horses. Diseases of the stifle joint remain a challenge for veterinarians. The objective of this study was to achieve a valuable acupuncture suggestive diagnosis to be considered for stifle joint diseases in horses. Thirty-nine nonlame horses involved in different activities were assessed. Acupuncture was independently performed by two evaluators. Reactions of the animal when pressurizing the point suggestive of stifle disease (PSSD), Bladder-20 and/or Bladder-21, were considered as the inclusion criteria for inclusion in the stifle group (SG, n = 31), and the animals with no reactions were assigne...
Ex vivo investigation of the effect of the transverse arytenoid ligament on abduction of the arytenoid cartilage when performing equine laryngoplasty. To investigate the effect of the transverse arytenoid ligament (TAL) on abduction of the arytenoid cartilage when performing laryngoplasty. Modified prosthetic laryngoplasty was performed on right and left sides of 13 cadaver larynges. Increasing force was sequentially applied to the left arytenoid cartilage at 3 N intervals from 0-24 N, when the force on the right arytenoid cartilage was either 0 or 24 N, before and after TAL transection. Digital photographs of the rostral aspect of the larynx were used to determine the left arytenoid abduction angles for these given force combinations and ...
Heterogeneity among traumatic spinal cord injuries at the thoracolumbar junction: helping select patients for clinical trials. Retrospective analysis. Methods: China Rehabilitation Research Center, Beijing, China. Objective: A retrospective study that documents the modalities and clarifies the heterogeneity among spinal cord injuries (SCIs) caused by trauma to the thoracolumbar vertebral junction. Methods: X-ray and MRI imaging, neurological records, and the urodynamics results of 190 patients were reviewed and used to categorize different SCI modalities. First, injuries were divided into complete and incomplete injuries using the International Standard for Neurological Classification of Spinal Cord Injury. Next, the ...