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 examination of the interspinous ligament in horses with overriding spinous processes. The equine interspinous ligament (ISL) consists of an oblique crossing arrangement of collagenous bundles which are thought to counteract the tensile and rotational forces of distraction between the spinous processes (SPs) in the caudal thoracic and cranial lumbar spine. The aim of this controlled histological study was to assess the structural anatomy and innervation of the ISL in horses with clinically significant overriding (dorsal) SPs (ORSPs) and to compare the findings with the ISL of normal horses. Samples of the ISL were obtained from 10 horses that underwent subtotal ostectomy for tre...
Morphological characteristics of mule conceptuses during early development. Hybrids between species are often infertile and extremely rare among mammals. Mules, i.e. crossing between the horse and the donkey, on the other hand are very common in agricultural and leisure practices due to their enhanced post-natal physical characteristics that is believed to occur for outbreeding or hybrid vigor. Since no reports are availableon the effects of hybrid vigor during early development, this study focused on characterizing the intrauterine development of mule conceptuses during critical embryo-to-fetus transition period. Nine embryos and fetuses of early gestation, obtained ...
Neuromyotonia in a horse. This article describes the clinical and electromyographic findings of neuromyotonia in a 19-month-old male crossbred Quarter Horse that presented with stiffness and muscle asymmetry in the hind limbs as well as sacrococcygeal, paravertebral, and gluteal myokymia. An electromyographic study showed spontaneous continuous muscle fiber activity with high-frequency discharges, fibrillations, positive sharp waves, fasciculation potentials, and complex repetitive discharges. Histological examination of the gluteal muscle showed a mixed neurogenic and myopathic pattern. The findings are consistent wit...
Quantitative Evaluation of Equine Articular Cartilage Using Cationic Contrast-Enhanced Computed Tomography. To investigate the diffusion trajectory of a cationic contrast medium (CA4+) into equine articular cartilage, and to assess normal and degenerative equine articular cartilage using cationic contrast-enhanced computed tomography (CECT). In the first experiment (Exp1), equine osteochondral specimens were serially imaged with cationic CECT to establish the diffusion time constant and time to reach equilibrium in healthy articular cartilage. In a separate experiment (Exp2), articular cartilage defects were created on the femoral trochlea (defect joint) in a juvenile horse, while the opposite joint...
Use of next generation sequencing to investigate the microbiota of experimentally induced wounds and the effect of bandaging in horses. To use next generation sequencing to characterize the microbiota of horses during healing of skin wounds in two anatomical locations (body and limb) known to present different healing patterns; and to investigate the impact of bandaging on bacterial communities of skin wounds located on the limbs of horses. Full-thickness skin wounds were created on the distal extremity of both thoracic limbs and on one lateral mid-thoracic wall of four healthy horses. Limb wounds were randomly assigned to bandaging or not. A full-thickness sample was collected with a biopsy punch from intact thorax and limb s...
Bone marrow lesions of the distal condyles of the third metacarpal bone are common and not always related to lameness in sports and pleasure horses. The metacarpophalangeal joint is a common site of pain in horses. Little information is available about bone marrow lesions in the distal condyles of the third metacarpal bone in sports and pleasure horses. Aims of this prospective, retrospective, observational study were to evaluate the prevalence of bone marrow lesions in the distal condyles of the third metacarpal bone, to describe their anatomic distribution and to correlate lesions with the presence of lameness and the level and type of activity. All sports and pleasure horses undergoing standing low-field MRI of the front fetlock region ...
The prevalence of temporal bone fractures is high in horses with severe temporohyoid osteoarthropathy. Temporohyoid osteoarthropathy is a well-recognized cause of equine neurologic disease. Temporal bone fractures associated with temporohyoid osteoarthropathy have been recognized with CT, however, little information is available regarding these fractures. The aims of this retrospective analytical study were to assess the prevalence of these fractures and to describe the specific configurations and associated imaging and clinical features. Fracture of the temporal bone was identified with CT in 16 of 39 included horses. All fractures were unilateral, minimally displaced and extended through the ...
In vitro mechanical evaluation of three transfixation pin-cast constructs applied to equine forelimbs. OBJECTIVE To compare strain at the bone-pin and cast-pin interfaces among 3 transfixation pin-cast constructs applied to equine forelimbs. ANIMALS 15 forelimbs from 15 adult horses. PROCEDURES Limbs were randomly assigned to 1 of 3 constructs. Centrally threaded positive-profile pins were used for all constructs, and the most distal pin was placed just proximal to the epicondyles of the third metacarpal bone. Construct 1 consisted of two 6.3-mm-diameter pins spaced 4 cm apart at 30° to each other. Construct 2 was the same as construct 1 except the pins were placed 5 cm apart. Construct 3 cons...
Surgical repair of a depressed, comminuted fracture of the zygomatic process of the frontal bone using a locking compression plate in a Thoroughbred colt foal. This case report demonstrates the use of a 10-hole 2.7-mm locking compression plate (LCP) to repair a depressed, comminuted fracture of the zygomatic process of the frontal bone, in a foal. LCP fixation resulted in excellent cosmesis. The use of LCP fixation in this region has not been previously described.
Diagnostic Approaches to Understanding Equine Limb Wounds. An accurate and timely diagnosis of the systemic and local tissue influences of a wound are essential to target successful treatment measures and reach the best result for an affected horse. A complete physical examination should be completed for any wounded horse and appropriate systemic therapies instituted. Visual and manipulative examinations aid in the complete understanding of wounded tissues. Imaging and invasive diagnostic techniques also have value in determining the extent of a wound. Considering what tissues are involved from an inside-out perspective can assist in developing a comp...
Ex vivo radiocontrast description of the caudal epigastric arteries in horses. To determine the location of the deep and superficial caudal epigastric arteries in relation to 3 midline positions and the relationship between the location of these arteries, body circumference, and body condition score. Methods: Descriptive anatomical study. Methods: Nine horses, aged 1-28 years (mean 10.61 ± 8.89 SD). Methods: Body condition score and body circumference were measured prior to euthanasia. Angiographic studies of the deep and superficial caudal epigastric arteries were performed on resected abdominal walls. The distances between the deep and the superficial caudal epiga...
Construction of the Equine Digestive System: A Tool for Teaching Topographical Anatomy. Anatomy is traditionally regarded as a difficult, non-motivating course involving a large body of theoretical and practical content, and it is often associated with high levels of dropout and failure. Given the relevance of the topic, we propose an alternative active multisensory teaching tool consisting of the construction of a low-fidelity anatomical model assembled into an articulated equine skeleton. Model construction and assembly assists students in the recognition of the topography and anatomical boundaries of the equine abdominal digestive system. Digestive system organs (liver, pancre...
Anatomy Teaching, a “Model” Answer? Evaluating “Geoff”, a Painted Anatomical Horse, as a Tool for Enhancing Topographical Anatomy Learning. Development of new methods for anatomy teaching is increasingly important as we look to modernize and supplement traditional teaching methods. In this study, a life-sized equine model, "Geoff," was painted with surface and deep anatomical structures with the aim of improving students' ability to convert theoretical knowledge into improved topographical anatomy knowledge on the live horse. Third and fourth year veterinary medicine students (n = 45) were randomly allocated into experimental (used "Geoff") and control (used textbook) groups. The efficacy of the model was evaluated through a struc...
In vitro comparison of linear vs triangular screw configuration to stabilize complete uniarticular parasagittal fractures of the proximal phalanx in horses. To assess fracture gap reduction and stability of linear vs triangular 4.5-mm lag screw repair of experimental, uniarticular, and complete forelimb proximal phalanx (P1) fractures. Methods: Experimental. Methods: Fourteen equine cadaver limbs/horses. Methods: Simulated fractures were repaired with 2 lag screws under 4-Nm insertion torque (linear repair). Computed tomography (CT) imaging was performed with the leg unloaded and loaded to forces generated while walking. The fracture repair was revised to include 3 lag screws placed with the same insertion torque (triangular repair) prior to CT. T...
Use of an aiming device and computed tomography for assisted debridement of subchondral cystic lesions in the limbs of horses. To describe the use of an aiming device (AD) and computed tomography (CT) for preoperative planning and intraoperative guided debridement of subchondral cystic lesions (SCL) in the limbs of horses and to determine the outcome 12 months after surgery. Methods: Prospective case series. Methods: Twelve horses referred because of lameness caused by 1 or 2 SCL (total of 14 SCL). Methods: All horses underwent CT-guided debridement of the SCL. The entry point of the drill bit and direction of drilling were planned and controlled by using a series of CT images and the AD. The SCL were curetted and fil...
Factors affecting side of ovulation in heifers and mares-A comparative study. Effect of side (left ovary, LO; right ovary, RO) and intraovarian presence of the regressing corpus luteum (CL) on the preovulatory follicle (PF) and ovulation were studied using ultrasonic- records of complete interovulatory intervals (IOI) for 500 IOI in heifers and 485 IOI in mares. Only IOI with a recording of side of a single PF and a single CL at each end of the IOI were used. In heifers, ovulation at the end of the IOI occurred more frequently (P < 0.0001) from RO (n = 285, 57%) than LO (n = 215, 43%). In mares, frequency of ovulation did not differ between RO (n = 250. ...
Magnetic resonance and radiographic imaging of a case of bilateral bipartite navicular bones in a horse. We describe the radiographic and magnetic resonance imaging findings associated with a case of bilateral forelimb bipartite navicular disease in a 7-year-old Warmblood gelding used for eventing. In addition to the radiographically evident partitioned navicular bones, magnetic resonance imaging (MRI) also detected other concurrent abnormalities occurring within the foot that have not been described before in other cases of navicular bone partition. MRI not only revealed soft tissue lesions of the podotrochlear apparatus, but also allowed for more detailed characterisation of the recently diagno...
Management of an extensive equine juvenile ossifying fibroma by rostral mandibulectomy and reconstruction of the mandibular symphysis using String of Pearls plates with cortical and cancellous bone autografts. To describe a surgical technique for rostral mandibulectomy and reconstruction of the mandibular symphysis. Methods: Case report. Methods: One 5-month-old warmblood cross filly. Methods: A preoperative diagnosis of a juvenile ossifying fibroma was made on the basis of clinical appearance and was later confirmed via histology. The tumor was large, rapidly growing and extending to the caudal aspect of the mandibular symphysis. Computed tomography was performed for surgical planning. The tumor was excised by performing a mandibulectomy caudal to the symphysis. The mandibular symphysis was reconst...
Regional and disease-related differences in properties of the equine temporomandibular joint disc. Temporomandibular joint (TMJ) disorders affect up to 12% of the human population, and naturally occurring TMJ diseases are increasingly recognized in animals. The TMJ disc plays a major role in TMJ disorders in people, but little is known about its role in TMJ pathology in animals. This study characterizes differences in properties of equine TMJ discs associated with age, disc region, and presence of TMJ osteoarthritis (OA). Discs were dissected from both TMJ's of sixteen horses euthanized for reasons unrelated to this study. Each joint was grossly evaluated and scored as normal, mild OA, or s...
Ultrasonography guidance for total splenectomy in donkeys. There are varieties of surgical approaches reported for equine splenectomy and all of them were dealing with the most reachable situation of splenic hilus and easy handling of the spleen. The aim of this work was to establish the normal ultrasound parameters of spleen in donkeys (normal echogenicity, hilus situation, topographic location and correlation with neighboring organs) as a guide to select the best approach for total splenectomy in donkeys. Splenic ultrasound was carried out on six normal donkeys before experimental total splenectomy in the standing position. The splenic topographic l...
Histological and Radiographic Evaluation of Equine Bone Structure after Implantation of Castor Oil Polymer. The main purpose of this study was to evaluate the characteristics of a vegetal polymeric biomaterial intended for bone substitution in horses and to investigate the responses of the equine third metacarpal bone to biomaterial implantation. Methods: Six horses were submitted to osteotomy on the dorsal aspect of the left and right third metacarpal bones; one bone defect was randomly selected for treatment with biopolymer, while the other was left untreated and served as a control. Bone density was monitored radiographically after surgery and bone biopsy fragments were collected at the end...
Equine Wound Management: Bandages, Casts, and External Support. Successful management of equine wounds relies on knowledge of the stages of wound healing, factors that can alter those stages, how healing stages can be manipulated, and adherence to the principles of wound healing. Challenges that complicate wound management include the inability to immobilize and/or confine equine patients, and maintain a clean environment during the critical initial stages of healing. Because of these challenges, the equine practitioner relies heavily on bandaging and external coaptation techniques to successfully treat and manage wounds. The type of bandage used is dictat...
Bursting strength of surgeon’s and self-locking knots for closure of ventral midline celiotomy in horses. To compare the bursting strength and failure mode of ventral midline celiotomy closed with a simple continuous suture pattern with 1 of 2 knot combinations, a novel self-locking knot combination of a forwarder start with an Aberdeen end knot (F-A) and a traditional combination of a surgeon's start with a surgeon's end knot (S-S). Methods: Ex vivo experimental. Methods: Equine cadavers (n = 14). Methods: A 20-cm ventral midline celiotomy was created in 14 equine cadavers. Horses were assigned to celiotomy closure with an F-A or S-S knot combination. Prior to closure, a 200-L inflatable blad...
Influence of neck position on commonly performed radiographic measurements of the cervical vertebral region in horses. OBJECTIVE To determine the influence of various neck positions on cervical vertebral radiographic measurements in horses. ANIMALS 18 client-owned horses examined for lameness but free of cervical disease. PROCEDURES Laterolateral radiographs of the cervical vertebrae from C1 through T1 were acquired for each horse in 3 neck positions (low, neutral, and high). Minimum sagittal diameter, intravertebral sagittal diameter (intra-VSD) ratio, inter-VSD ratio, length of the articular processes joint ratio, vertebral alignment angle, and vertebral fossa angle were measured at each segment in each neck...
Anatomy of the vestibulum esophagi and surgical implications during prosthetic laryngoplasty in horses. To describe the anatomy of the entry to the equine esophagus (vestibulum esophagi) and to assess the risk of penetrating its adventitia and/or lumen during laryngoplasty. Methods: Ex vivo cadaveric study. Methods: Five isolated equine larynges and 39 equine head and neck specimens. Methods: The anatomy of the vestibulum esophagi was studied by dissection of 5 cadaver specimens. Then, a bilateral laryngoplasty was performed, including 5 suture placements through the muscular processes, caudal, rostral, and sagittal, with straight and curved needles. Two of the 3 surgeons performing the implanta...
Cervical stabilization with polyaxial pedicle screw and rod construct in horses: A proof of concept study. To evaluate safety and efficacy of a novel technique for cervical stabilization. Methods: In vivo experimental. Methods: Four normal adult quarterhorse crossbreed horses (2-4 years of age, > 250 kg). Methods: One mid-cervical spinal unit (C3-C4) was distracted with a porous metal interbody fusion device (IFD) and stabilized with a polyaxial pedicle screw and rod construct. Neurologic examinations were performed preoperatively and postoperatively. Radiographs of the fusion site and adjoining vertebrae were obtained preoperatively and monthly. Horses were euthanized at 8 months and spin...
Comparison of two techniques for transpharyngeal endoscopic auditory tube diverticulotomy in the horse. Auditory tube diverticula, also known as guttural pouches, are naturally occurring dilations of the auditory tube in horses that communicate with the nasopharynx through a small ostium. Infection and select other conditions can result in inflammation and narrowing of the nasopharyngeal ostium, which prevents drainage of fluid or egress of air and can lead to persistent infection or guttural pouch tympany. Auditory tube diverticulotomy allows continuous egress from the auditory tube diverticula and is a feature of disease treatment in horses, in which medical treatment alone is not successful. ...
A novel radiographic projection for the detection of sagittal plane slab fracture of the equine third carpal bone. Some sagittal plane fractures of the equine third carpal bone are difficult to detect with conventional radiographic projections. Objective: To describe a novel radiographic projection for the detection of sagittal plane slab fractures of the equine third carpal bone. Methods: Retrospective study of radiological records. Methods: From a first opinion Thoroughbred racehorse caseload, cases were included for analysis if sagittal fracture of the third carpal bone was evident on a dorsoproximal lateral-palmarodistal medial oblique (DPrL-PDiMO) projection of the distal row of carpal bones and not v...