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.
Histological and biomechanical properties of systemic arteries in young and old Warmblood horses. Arterial rupture is a well-recognized cause of sudden death in horses, which mainly affects older horses. The arterial wall is known to stiffen with age, although the underlying age-related histological and biomechanical changes remain unclear. The purpose of this study was to investigate the effect of aging by histological analysis of the arterial wall and examination of the arterial wall biomechanical properties using an inflation-extension test. Entire circular samples of the proximal and distal aorta, cranial and caudal common carotid, external iliac, femoral and median artery were collect...
Comparison of one-layer Utrecht pattern with two-layer (simple continuous/Cushing) pattern for jejunojejunostomy in healthy horses in vivo. To compare end-to-end jejunal anastomoses with a one-layer (Utrecht) and two-layer (simple continuous/Cushing) patterns. Methods: Experimental study. Methods: Eight healthy adult horses. Methods: Jejunal end-to-end anastomoses were performed in randomly assigned one-layer or two-layer patterns. Horses were recovered from surgery and monitored for complications. At 14 days, the opposite pattern was performed (cross-over design) prior to euthanasia. Duration of closures was compared between patterns. Serosal width was measured before harvesting anastomotic sites from the first procedure. Lumin...
Contrast Enhanced Computed Tomography Findings in 105 Horse Distal Extremities. The poor soft tissue conspicuity of CT can be improved by using intra-arterial CT Angiography (CTA), and intra-articular and intra-bursal contrast enhanced CT (CTAR). This retrospective study describes a combination protocol of CT and CTA of the horse's foot, and CTAR of the distal interphalangeal joint and navicular bursa. It is hypothesized this would provide a comprehensive overview of the range and severity of distal limb pathology. Radiology reports of all horses admitted for distal limb CT over a 5 year period were reviewed. All horses with a complete four stage CT examination and radiol...
Morphometric analysis of the His bundle (atrioventricular fascicle) in humans and other animal species. Histological and immunohistochemical study. The His bundle is a part of the specialized electrical conduction system that provides a connection between the atrial and ventricular myocardial compartments in both normal and abnormal hearts. The aim of this study was to perform a morphometric analysis of His bundle characteristics of in humans, dogs, horses and pigs and compare them in these studied species. Histological sections of 5 μm thickness were obtained and stained with hematoxylin-eosin and Masson's trichrome; the desmin and periodic acid-Schiff methods were also used for precise identification of cells. The His bundle was found...
Evaluation of platelet-rich plasma applied in the coronary band of healthy equine hooves. Platelet-rich plasma (PRP) is a widely used hemocomponent that holds great promise in equine medicine due to its feasible production and regenerative therapy potential. Its use has been considered as a treatment for chronic laminitis, mainly in terms of its analgesic properties and because it can induce growth in affected hooves. The aim of this study was to evaluate the effect on hoof growth attributable to PRP applied in the coronary band of clinically healthy horses by comparing the responses to PRP, saline, and trimming alone. After randomization, the forelimbs of 9 horses received specifi...
3D kinematic of the thoracolumbar spine in Mangalarga Marchador horses performing the marcha batida gait and being led by hand-A preliminary report. This study aimed to provide a preliminary description of the sagittal and transverse plane kinematics of the thoracolumbar spine of Mangalarga Marchador (MM) horses performing the marcha batida gait, led in-hand. We evaluated the pattern of angular movement and the mean amplitude of six specific angles. An optoelectronic system was used for 3D kinematic analysis (19 cameras, 250 Hz). They were positioned around the horses and an acquisition volume of 16 × 4.8 × 3 meters was used. Eight retroreflective markers were fixed on the spine of the animals over thoracic vertebrae 8 (T8), 12 (T12), 15...
A computed tomographic study of endodontic and apical changes in 81 equine cheek teeth with sagittal fractures. Sagittal fractures of equine cheek teeth are commonly observed during oral examination. There are few reports on the apical and endodontic pathology associated with such fractures seen during computed tomographic (CT) examination. Objective: This study aimed to document the prevalence of CT changes indicative of apical disease in equine cheek teeth, which have suffered a sagittal fracture involving the clinical ± reserve crown. Methods: This study is a retrospective case series. Methods: CT examinations of equine heads with sagittal fractures of cheek teeth present were reviewed: 81 teeth f...
Comparison Between Ultrasonographic and Standing Magnetic Resonance Imaging Findings in the Podotrochlear Apparatus of Horses With Foot Pain. This prospective study aimed to blindly compare the ultrasonographic and standing magnetic resonance imaging (sMRI) findings in deep digital flexor tendon (DDFT), navicular bone, and navicular bursa in horses with foot pain, positive digital analgesia, and without definitive radiographic diagnosis. Ultrasonography detected more DDFT abnormalities (32/34 feet vs. 27/34 with sMRI) but identified less palmar navicular abnormalities (23/34 feet vs. 30/34 with sMRI). In suprasesamoidean DDFT lesions, which were mainly dorsally located, changes in echogenicity did not correspond to a particular patt...
Correlated Imaging of the Equine Hyoid Apparatus Using CT, Micro-CT, and Histology. Detailed radiological evaluation of the normal hyoid apparatus by computed tomography (CT) has not yet been conducted. Thus, it is unclear what type of junction connects the different parts of the equine hyoid apparatus. To describe the normal CT anatomy of the equine hyoid apparatus, and to determine the junction type that connects the different parts of the hyoid apparatus. Combination of retrospective study and prospective cadaver study. The medical records of horses that underwent head CT scans from 2009 to 2018 were retrieved. Inclusion criteria for the CT scans were visibility of at ...
Comparison of the Effect of High-Intensity Laser Therapy (HILT) on Skin Surface Temperature and Vein Diameter in Pigmented and Non-Pigmented Skin in Healthy Racehorses. The aim of the study was to assess differences in the influence of high-intensity laser therapy (HILT) on the skin surface temperature and vein diameter of the lateral fetlock joint region in a group of racehorses with pigmented and non-pigmented skin in the treatment area. Twenty Thoroughbreds were divided into two equal groups: pigmented and non-pigmented skin groups. Each horse received the same HILT treatment. Just before and immediately after HILT, thermographic examination was performed to measure the skin surface temperature and ultrasonographic examination assessed the lateral digital ...
Slab fractures of the third carpal bone involving both radial and intermediate facets and outcomes after surgical repair in racing Quarter Horses. Characteristics and outcomes after surgical repair of third carpal bone (C3) slab fractures involving both radial and intermediate facets in racing Quarter Horses are unknown. Objective: To describe the pre- and intraoperative characteristics of C3 slab fractures of both radial and intermediate facets in Quarter Horses and to report on the long-term outcomes after internal fixation. Methods: Retrospective case series. Methods: Case records were collected from racehorses with C3 slab fractures between 2008 and 2020. Inclusion criteria required arthroscopic-guided repair of C3 slab fractures inv...
Deep digital flexor tendon lesions in the pastern are associated with the presence of distal tendinopathy. Correct diagnosis and characterisation of deep digital flexor tendon (DDFT) lesions in equine athletes allows targeted treatment and improved prognostication. Objective: To assess the prevalence and character of pathological change within the DDFT in the pastern with concurrent tendon injury distally. It is hypothesised that tendon lesions in the pastern will be associated with tendinopathy within the hoof capsule. Methods: Retrospective descriptive case series. Methods: Cases with DDFT lesions in the pastern and magnetic resonance imaging (MRI) or ultrasonography of the foot were evaluated re...
Intratendinous Fibroma of the Superficial Digital Flexor Tendon within the Carpal Sheath of a Horse. A 20-year-old British Warmblood gelding was presented for a progressively worsening right forelimb lameness which developed following an intense dressage training session. Initial ultrasound examination revealed a triangular, intrathecal, hypoechoic region within the superficial digital flexor tendon (SDFT) in the proximal, palmar carpal region distal to the accessory carpal bone (ACB), extending 7cm distally into the proximal metacarpal region. No significant improvement in clinical presentation was observed following an eight-week rehabilitation programme. Repeat ultrasound examination revea...
An Estimation of Lameness in Sable Island Horses Using Radiographic Evaluation of the Distal Phalanx and Hoof Capsule. Laminitis is a painful condition that causes lameness in horses. However, monitoring this condition in feral horses is logistically difficult. Laminitis can be detected postmortem, as inflammation of the sensitive laminae of the hoof changes the relative location of the bony structures within the hoof capsule. Thus, evaluation of cadavers may be used to estimate laminitis prevalence in feral populations of horses. The objective of this study was to estimate the prevalence of laminitis in feral horses inhabiting the Sable Island National Park Reserve, Canada, using radiographic imagery on the h...
Localisation of Cannabinoid and Cannabinoid-Related Receptors in the Horse Ileum. Colic is a common digestive disorder in horses and one of the most urgent problems in equine medicine. A growing body of literature has indicated that the activation of cannabinoid receptors could exert beneficial effects on gastrointestinal inflammation and visceral hypersensitivity. The localisation of cannabinoid and cannabinoid-related receptors in the intestine of the horse has not yet been investigated. The purpose of this study was to immunohistochemically localise the cellular distribution of canonical and putative cannabinoid receptors in the ileum of healthy horses. Distal ileum spec...
Relationship Between Body Mass and the Hoof Area: Understanding the Turner’s Formula. The equine hoof balance has been the subject of several studies, reflecting the importance of hooves for the good health and performance of these animals. An important condition for the hooves health is its loading, where too much weight in a small area can increase the chances of lameness. Therefore, an equation has been proposed to identify the relationship between body mass and hoof size and has been used in several studies. However, a clear description of how it was developed and what its results really indicate is not available in the literature. In light of this, this article aims to des...
Gross post-mortem and histological features in 27 horses with confirmed lumbosacral region pain and five control horses: A descriptive cadaveric study. There is a lack of understanding of the pathological and/or physiological nature of lumbosacral region pain. Objective: To describe the gross variations of the osseous and soft tissues of the lumbosacral region and report the histological findings of sections of nerve tissue in affected and control horses. Methods: Descriptive post-mortem case series. Methods: All horses had undergone full clinical and gait assessment, including ridden exercise. Horses with a substantial response to infiltration of local anaesthetic solution around the sacroiliac joint regions were included in the affected gro...
Development and Validation of a Three-Dimensional Printed Training Model to Teach Ultrasound-Guided Injections of the Cervical Articular Process Joints in Horses. Intra-articular injections are routinely performed to alleviate pain and inflammation associated with osteoarthritis in horses. Intra-articular injections require accurate needle placement to optimize clinical outcomes and minimize complications. This study's objectives were to develop and validate a three-dimensional (3D) printed model of an equine cervical articular process joint to teach ultrasound-guided injections. Five identical models of an equine cervical articular process joint were 3D printed and embedded in 10% ballistic gelatin. Experts' and novices' ability to successfully insert ...
Use of Tubo-Ovarian Ligation Via Colpotomy as A Potential Method for Sterilization in Mares. The goal of this study was to develop a safe, effective, and economical method for permanent sterilization of mares based upon tubo-ovarian ligation performed via colpotomy. In this study, we evaluated the application of a nylon cable tie (zip-tie) to the ovarian pedicle and oviduct of mares to induce ovarian ischemia and tubal ligation without removal of ovaries. Initially, efficiency of zip-ties on the ovarian pedicle was tested in vitro and in vivo. Based on the absence of leakage through the zip-tie ligated vessels in anatomic specimens, we confirmed the potential efficacy of the technique...
A bronchopulmonary artery fistula in a horse. A 24-year-old, Thoroughbred gelding presented with difficulty breathing for a few days and intermittent nose bleeding before dying. At necropsy, the bronchoesophageal artery and the bronchial artery that flowed into the left anterior lobe were tortuous and dilated, and it was found that dilated tortuous branches of the bronchial artery ran over the dorsal and ventral surfaces of the left anterior lobe. Histopathologically, an anastomosis between a muscular artery and an elastic artery were demonstrated, which were identified as bronchial and pulmonary arteries, respectively. Based on the gross...
Castration Complications: A Review of Castration Techniques and How to Manage Complications. Castration is one of the most common surgical procedures performed in equine practice. Open, closed, and semiclosed techniques are described for castration of horses, and the procedure may be performed in a standing, sedated animal or in a recumbent animal under general anesthesia. Although a relatively routine procedure, complications can occur, with reported complication rates ranging from 10.2% to 60%. Most complications are mild and resolve rapidly with appropriate treatment, but more serious or life-threatening complications can also occur. A thorough knowledge of male reproductive anatom...
Position of the midline septum of the guttural pouches in horses subjected to computed tomography. Standing computed tomographic (CT) examination of the equine guttural pouch frequently reveals deviation of the midline septum. The significance of deviation is currently unknown. The aims of this retrospective, single-centre study were to determine the prevalence of deviation of the midline septum of the guttural pouch and determine whether there was an association between the presence and degree of deviation of the septum, and guttural pouch disease. Case records were reviewed, identifying 95 horses that had undergone a standing, sedated, head CT and guttural pouch endoscopy. The presence, l...
The Bone Cartilage Interface and Osteoarthritis. This review describes results obtained with tissue from prior studies of equine and human osteoarthritis (OA). The main methods considered are scanning electron microscopy, novel methods in light microscopy and X-ray Micro-tomography. The same samples have been re-utilised in several ways. The tissues described are hyaline articular cartilage (HAC; or substitutes), with its deep layer, articular calcified cartilage (ACC), whose deep surface is resorbed in cutting cone events to allow the deposition of subchondral bone (SCB). Multiple tidemarks are normal. Turnover at the osteochondral (ACC-HAC...
Ultrasonography Evaluation of Umbilical Structures in Clinically Healthy Donkey Foals during the First Week of Life. The umbilicus is a potential access-point for pathogens in equine foal, causing umbilical infections and potentially life-threating illness. Early diagnosis based on ultrasonographic appearance and measurement is crucial to avoid severe complications and promptly implement appropriate therapy. This study ultrasonographically evaluates the umbilical remnants of donkey foals, in the first week of life. Fifteen healthy donkey foals were included in the study. The umbilical vein, arteries and urachus ultrasounds were performed at 24 h, 3 and 7 days of life, using a portable ultrasound machine and ...
Evaluation of the Filum Terminale in Hereditary Equine Regional Dermal Asthenia. The objectives of this study were to describe the anatomy, histology, and ultrastructure of the equine filum terminale (FT) and to describe the FT in hereditary equine regional dermal asthenia (HERDA), a model of human Ehlers-Danlos syndromes (EDS). Those humans suffer from tethered cord syndrome (TCS) caused by an abnormally structured FT wherein its attachment at the base of the vertebral column leads to long-term stretch-induced injury to the spinal cord. The pathophysiology of TCS in EDS is poorly understood, and there is a need for an animal model of the condition. Histopathologic and ult...
Heterotopic Polyodontia: Diagnosis and Surgical Removal of a Dentigerous Cyst Comprising 2 Dental Structures in a 14-Year-Old Horse. A 14-year-old American Paint Horse mare was referred for further evaluation of a firm mass with an associated draining tract at the base of the left ear suspected to be a dentigerous cyst. Approximately three months prior, the draining tract had been excised under the presumed diagnosis of an abscess with no improvement. Physical examination revealed a firm mass palpable at the base of the left ear with a draining tract that did not elicit any pain response on palpation. Digital radiographs revealed a 6x11cm mineral mass in the left temporal region. Medially, there were two projections that ex...
Extracranial guiding structures for navigation to specific topographical sectors of the equine neopallium: an anatomical investigation performing three-dimensional distance measurements in adult warm-blooded horses. This basically anatomical study focuses on two items; firstly, the establishment of a system for the cartographic subdivision of the neopallium; secondly, the topographical correlation of extracranial landmarks and intracranial sites on the neopallium. Methods: The surface of the neopallium was subdivided into 15 sectors with reference to a newly introduced pattern of Primary Sulci. The topographical link between extracranial landmarks and certain intracranial sites (i.e. neopallium sectors) was elaborated by using a simple stereotactic device and a computer-assisted measurement device. Measur...
Development of a constant pressure perfused ex vivo model of the equine larynx. Distal axonopathy is seen in a broad range of species including equine patients. In horses, this degenerative disorder of the recurrent laryngeal nerve is described as recurrent laryngeal neuropathy (RLN). The dysfunctional innervation of the cricoarytenoideus dorsalis muscle (CAD) leads to a loss of performance in affected horses. In general, ex vivo models of the larynx are rare and for equine patients, just one short report is available. To allow for testing new therapy approaches in an isolated organ model, we examined equine larynges in a constant pressure perfused setup. In order to chec...
A comparative study of breed differences in the anatomical configuration of the equine vertebral column. The importance of the equine thoracolumbar vertebral column in orthopaedic disorders is well recognized and diagnostic imaging becomes more feasible, but little is known about variations in the anatomical configuration within breeds. In this descriptive post-mortem study, anatomical variations in three widely differing breeds: Warmblood horses, Shetland ponies and semi-feral Konik horses are described. The caudal cervical (C), thoracic (T), lumbar (L) and sacral (S) regions of the vertebral column of 30 Warmblood horses, 29 Shetland ponies and 18 Konik horses were examined using computed tomog...
Multidetector CT and cone-beam CT have substantial agreement in detecting dental and sinus abnormalities in equine cadaver heads. The performance of cone-beam CT (CBCT) systems compared to conventional helical multidetector CT (MDCT) imaging of the equine head is unknown. The aim of this prospective, method-comparison study was to compare the ability of CBCT and MDCT to detect abnormalities in equine cadaver heads. Eleven equine cadaver heads were scanned using a CBCT scanner and a 64-slice MDCT scanner. Consensus evaluations for CBCT and MDCT scans were performed by three observers. Identified abnormalities were grouped into subcategories with a focus on dental abnormalities. Kappa agreement values between detected abno...