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.
Caudal foot placement superior to toe elevation for navicular palmaroproximal-palmarodistal-oblique image quality. Palmaroproximal-palmarodistal oblique (PaPr-PaDiO) radiographs are regularly obtained for a full evaluation of the navicular bone (NB). Despite their routine use, different acquisition techniques are described. Objective: To determine optimal foot placement and beam angle for obtaining PaPr-PaDiO views. Methods: In vitro experiment. Methods: A convenience sample of 26 disarticulated forelimbs were placed in six different positions using a leg press to mimic the weight-bearing position. In each position, navicular PaPr-PaDiO images were obtained with eight different beam angles. The resulting 1...
Computed tomographic assessment of fracture characteristics and subchondral bone injury in Thoroughbred racehorses with lateral condylar fractures and their relationship to outcome. To investigate the effects of fracture characteristics and concurrent subchondral bone pathology identified with computed tomography (CT) on the racing performance of Thoroughbred racehorses with fractures of the MC3/MT3 lateral condyle. Methods: Retrospective cohort study. Methods: Thoroughbred racehorses (n = 50) with a fracture of the MC3/MT3 lateral condyle, which had preoperative CT and internal fixation performed. Methods: Medical records were reviewed for age, sex, limb, and surgical treatment. Computed tomography scans were evaluated to determine fracture characteristics including le...
An objective index for spinal cord compression on computed tomography in Thoroughbred horses. Computed tomographic myelography can be a useful tool for evaluating vertebral canal stenosis. However, an index of spinal cord compression is yet to be established. This observational descriptive study aimed to establish an index for spinal cord compression using computed tomography (CT). Twenty-three Thoroughbred horses (age, 155-717 days; weight, 205-523Â kg) with suspected cervical vertebral malformation were subjected to computed tomographic myelography in dorsal recumbency using large-bore gantry CT to define the entire cervical vertebrae from C1 to C7. Subsequently, the height of the sp...
Alobar Holoprosencephaly in an Aborted American Quarter Horse Fetus. Holoprosencephaly is a central nervous system malformation, characterized by incomplete or total lack of division of prosencephalon hemispheres, which is commonly accompanied by craniofacial malformations. A 9-month-gestation aborted American Quarter Horse fetus was submitted for postmortem examination. The fetus lacked haircoat and had severe facial malformations including marked shortening/absence of the maxillary, incisive and nasal bones, bilateral anophthalmia, and pre-maxillary agenesis. The prosencephalon was small and nearly spherical, represented by a single lobe, with no visible sepa...
Computed tomographic geometrical analysis of surgical treatments for equine recurrent laryngeal neuropathy. To characterize the 3-D geometry of the equine larynx replicating laryngeal hemiplegia and 4 surgical interventions by use of CT under steady-state airflow conditions. Secondly, to use fluid mechanic principles of flow through a constriction to establish the relationship between measured airflow geometries with impedance for each surgical procedure. Methods: 10 cadaveric horse larynges. Methods: While CT scans were performed, inhalation during exercise conditions was replicated for each of the following 5 conditions: laryngeal hemiplegia, left laryngoplasty with ventriculocordectomy, left lary...
Measurement accuracy of foot conformation parameters on low-field magnetic resonance images in horses. Foot imbalance and malalignment of the digits are common in horses. Angle and distance measurements performed on bones, joints and hoof wall on radiographs provide essential guidance for precise corrective trimming and shoeing. This study aimed to investigate, if selected standing low-field magnetic resonance (MR) images can be used to accurately measure dorsopalmar and lateromedial foot conformation parameters in comparison to the radiographic gold standard. Images of 100 horses referred for standing low-field MR examination were selected. Foot conformation angles and distances were measured ...
Physical Activities and Morphologic Aspects of the Equine Fetus During Days 40-150. Intrauterine mobility of the fetal-amniotic unit is unique in equids among domestic species. Intrinsic activity begins as head nods on ∼ Day 40 (Day 0 = ovulation) and by Day 60 has progressed into intermittent subtle to vigorous head, neck, limb, and body movements. On Days 60-100, fetal mobility is maximal with traveling of the fetal-amniotic unit throughout an allantoic pool that encompasses the uterine horns, and uterine body. The fetus may be entirely within one uterine horn with the horn entrance closed behind it, and then may work through the entrance into the uterine body. Mobility...
Advances in the Diagnosis of Equine Respiratory Diseases: A Review of Novel Imaging and Functional Techniques. The horse, as a flight animal with a survival strategy involving rapid escape from predators, is a natural-born athlete with enormous functional plasticity of the respiratory system. Any respiratory dysfunction can cause a decline in ventilation and gas exchange. Therefore, respiratory diseases often lead to exercise intolerance and poor performance. This is one of the most frequent problems encountered by equine internists. Routine techniques used to evaluate respiratory tract diseases include clinical examination, endoscopic examination, radiographic and ultrasonographic imaging, cytological...
The failure mode of a mechanically loaded equine medial femoral condyle analog with a void and the impact of lag and neutral screw placement. To determine the failure method of simulated equine medial femoral condyle (MFC) subchondral bone defects under compression and the influence of screw placement on failure resistance. Methods: In vitro study. Methods: Composite disks (CD) simulating the moduli of yearling bone in the MFC. Methods: Four CD conditions were tested, all with a 12.7 mm void (n = 6 per condition): intact (no void), void only, void with a 4.5 mm screw placed in neutral fashion, and void with a 4.5 mm screw placed in lag fashion. Composite disks of each condition were tested under monotonic compression to 6000...
A New Anorganic Equine Bone Substitute for Oral Surgery: Structural Characterization and Regenerative Potential. Different xenogeneic inorganic bone substitutes are currently used as bone grafting materials in oral and maxillo-facial surgery. The aim of the present study was to determine the physicochemical properties and the in vivo performance of an anorganic equine bone (AEB) substitute. AEB is manufactured by applying a process involving heating at >300 °C with the aim of removing all the antigens and the organic components. AEB was structurally characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray fluorescence (XRF), and Fourier-transformed infrared (FT-IR) spectros...
Corneal thickness and anterior chamber depth of the normal adult horse as measured by ultrasound biomicroscopy. To determine corneal thickness (CT) and axial anterior chamber depth (ACD) using ultrasound biomicroscopy (UBM) in normal adult horses. To compare corneal thickness measurements between UBM and ultrasonic pachymetry. Methods: Sixty eyes of 30Â healthy adult horses aged 8-24Â years. Methods: Ultrasonic pachymetry (velocity of 1640Â m/s) was utilized to obtain measurements of the central, superior, temporal, inferior, and nasal cornea. Triplicate images of the same corneal locations were acquired using UBM (50Â MHz). Images of the axial anterior chamber were used to measure ACD. Intraocular pres...
The Gingiva of Horses With Pituitary Pars Intermedia Dysfunction: A Macroscopic Anatomical Evaluation. Pituitary pars intermedia dysfunction (PPID) is a common neurodegenerative disease mainly in horses older than 15 years. The domestic equine population is following the same demographic change as that seen in humans; it is aging and veterinarians are asked to attend to geriatric horses more frequently. Common problems seen regularly in older equines are dental disorders and especially periodontal disease. As a systemic and endocrine disease, associated with delayed wound healing and impaired immune function, PPID should be considered before major dental treatment in aged equines is started. Po...
Dynamic three-dimensional computed tomographic imaging facilitates evaluation of the equine cervical articular process joint in motion. Dynamic computed tomography (CT) imaging has been introduced in human orthopaedics and is continuing to gain popularity. With dynamic CT, video sequences of anatomical structures can be evaluated in motion. Objective: To investigate the feasibility of dynamic CT for diagnostic imaging of the equine cervical articular process joints (APJs) and to give a detailed description of the APJ movement pattern. Methods: Descriptive cadaver imaging. Methods: Cervical specimens of twelve Warmblood horses were included. A custom-made motorised testing device was used to position and manipulate the neck spe...
How to perform a percutaneous cecal or colonic trocarization in horses with severe abdominal tympany. Cecal or colonic gas tympany of any cause may result in increased intraabdominal pressure, causing a significant decrease in venous return and cardiac output. Trocarization of the large colon or cecum in the event of large intestinal tympany may resolve gas distension and accompanying increased intraabdominal pressures sufficiently enough to promote resolution of a displaced large colon. Furthermore, trocarization of the medical colic may decrease morbidity and mortality associated with severe intraabdominal hypertension. Methods: This how-to description details the technique of transcutaneous...
Incidence of superficial abdominal organ identification is similar using high-frequency linear (transrectal) and low-frequency curvilinear (abdominal) transducers in clinically healthy horses: A pilot study. Abdominal organ displacement is a potentially life-threatening condition in horses. Primary care veterinarians commonly make referral decisions based on a combination of clinical and ultrasonographic findings. However, published studies describing the effects of transducer on identifying abdominal organ locations in horses are currently lacking. The objective of this prospective, methods comparison, pilot study was to compare organ identification using a high-frequency linear (transrectal) transducer and a low-frequency curvilinear (abdominal) transducer for transcutaneous abdominal ultrasonog...
Osteochondrosis and other lesions in all intervertebral, articular process and rib joints from occiput to sacrum in pigs with poor back conformation, and relationship to juvenile kyphosis. Computed tomography (CT) is used to evaluate body composition and limb osteochondrosis in selection of breeding boars. Pigs also develop heritably predisposed abnormal curvature of the spine including juvenile kyphosis. It has been suggested that osteochondrosis-like changes cause vertebral wedging and kyphosis, both of which are identifiable by CT. The aim of the current study was to examine the spine from occiput to sacrum to map changes and evaluate relationships, especially whether osteochondrosis caused juvenile kyphosis, in which case CT could be used in selection against it. Whole-body ...
CT is a feasible imaging technique for detecting lesions in horses with elbow lameness: A study of 139 elbows in 99 horses. Computed tomography (CT)is increasingly available in veterinary referral practices; however, published studies describing CT lesions of the equine elbow are currently lacking. In this single-center, retrospective, observational study, horses undergoing elbow CT at Equitom between July 2015 and October 2018 were reviewed. Subchondral bone sclerosis; resorption of the radius, ulna, and humerus; osteophyte; and enthesophyte lesions were graded. One hundred thirty-nine elbows of 99 horses (16 with elbow pain and 123 control elbows) were included (median age, 9 years). Osseous cyst-like lesions (nÂ...
Comparing Blind and Ultrasound-Guided Retrobulbar Nerve Blocks in Equine Cadavers: The Training Effect. In standing ophthalmic surgery in horses, a retrobulbar nerve block (RNB) is often placed blindly for anesthesia and akinesia. The ultrasound (US)-guided RNB may have fewer complications, but the two techniques have only been compared once in equine cadavers. This study compares the techniques for success and complication rates and analyzes the effect of training on US guidance. Twenty-two equine cadavers were divided into three groups: blind RNBs were performed bilaterally in eight cadavers, US-guided RNBs were performed bilaterally in seven cadavers, and after US-guided training, blind RNBs ...
Anatomical position of the palmar/plantar nerves at the metacarpal/metatarsal distal level in horses: An in vivo study by means of ultrasonography. The neurovascular bundle of the equine distal cannon can dynamically vary with limb position, and this can affect the performance of low 4- or 6-point block. This study aims to identify and describe the anatomical position and variations of the lateral and medial palmar/plantar nerve at the metacarpal/metatarsal distal level in horses by ultrasonography. Eight mares underwent ultrasound examination on the lateral and medial palmar/plantar sides of the metacarpus/metatarsus. Images were obtained for measurements of the cross-sectional area of the nerve, distances between the nerve and the skin ...
Effects of Internal Fluid Pressure on Stresses in Subchondral Bone Cysts of the Medial Femoral Condyle. The etiology of subchondral bone cysts (SBCs) is not fully understood. Mechanical trauma and fluid pressure are two mechanisms believed to cause their formation and growth. The equine stifle joint provides a natural animal model for studying SBCs. Computed tomography images of an extended yearling cadaveric stifle joint were segmented using ScanIP to isolate bones and relevant soft tissues. Three model geometries were created to simulate cyst sizes of approximately 0.03 cm (C1), 0.5 cm (C2), and 1 cm (C3). A uniform pressure resulting in 3000Â N force was applied at the proximal end of the fem...
Pneumoperitoneum as an uncommon complication after an axillary laceration in a horse. Lacerations of the axillary region occur frequently in horses. Typical complications caused by entrapment of air in the wound during locomotion are subcutaneous emphysema, with consecutive pneumomediastinum and pneumothorax. In this case report, the clinical, radiographic and laboratory diagnosis and management of these complications after an axillary laceration that finally resulted in pneumoperitoneum are described. A 1-year-old Hannoveranian was presented with a pre-existing axillary laceration of unknown duration and subcutaneous emphysema in the surrounding tissue. Due to extensive tissue...
Intervertebral disc degeneration in warmblood horses: Histological and biochemical characterization. Gross morphology of healthy and degenerated intervertebral discs (IVDs) is largely similar in horses as in dogs and humans. For further comparison, the biochemical composition and the histological and biochemical changes with age and degeneration were analyzed in 41 warmblood horses. From 33 horses, 139 discs and 2 fetal vertebral columns were evaluated and scored histologically. From 13 horses, 73 IVDs were assessed for hydration, DNA, glycosaminoglycans, total collagen, hydroxyl-lysyl-pyridinoline, hydroxylysine, and advanced glycation end-product (AGE) content. From 7 horses, 20 discs were ...
A Computerized Simulation of the Occlusal Surface in Equine Cheek Teeth: A Simplified Model. Equine mastication, as well as dental wear patterns, is highly important for the development of treatments in equine dentistry. During the last decades, the stress and strain distributions of equine teeth have been successfully simulated using finite element analysis. Yet, to date, there is no simulation available for dental tooth wear in equines. In this study, we developed a simplified two-dimensional computer simulation of dental wear. It provides a first tentative explanation for the development of the marked physiological inclination of the occlusal surface and for pathological conditions...
The influence of the metacarpophalangeal joint angle on the transversal area and mean echogenicity of the superficial digital flexor tendon and suspensory ligament in gaited horses. The objective of this study was to assess the influence of the metacarpophalangeal (MCP) joint angle on the transversal area (TA) and mean echogenicity (ME) of the superficial digital flexor tendon (SDFT) and suspensory ligament (SL) in gaited horses. Ultrasound images were obtained from 50 healthy adult horses of the Mangalarga Marchador (MM; n=25) and Campeiro (n=25) breeds. Static and dynamic angles of the MCP joint were measured from photographs and video recordings. Higher ME values were evinced for the SL only in the group with the smaller dynamic angles of the MCP joint in the MM horses...
Ultrasound-guided injections of the equine head and neck: review and expert opinion. Ultrasound-guided injections can be used for a wide variety of conditions in the horse, including both diagnostic and therapeutic applications. Benefits of ultrasound guidance include more accurate deposition of injectate compared with blind approaches. Improved identification of vital structures, including nerves and blood vessels, allows their avoidance and thus reduces procedure-associated complications. Validation of such ultrasound-guided techniques has shown that they can be easily learnt by inexperienced veterinarians, assuming a proper knowledge of the sonographic anatomy. In many case...
Comparison of Bone Mineral Content of the Equine Third Metacarpal to Total Radiographic Bone Aluminum Equivalents From Unprocessed Digital Radiographs. Digital radiographs are common for estimating bone mineral content (BMC) in horses with radiographic bone aluminum equivalents (RBAE). Processing algorithms are used to produce clearer images of digital radiographs in clinical settings, but this distorts RBAE. This study compared RBAE from digital radiographs to BMC from bone ash, and physical and digital morphology measurements. Digital radiographs were taken of six third metacarpals (MCIII) from equine cadavers with an aluminum step wedge penetrometer. A 2-cm transverse section of bone was digitally analyzed and excised from each MCIII. For ...
Multivariable Logistic Regression Models of X-Ray Thoracic Spinous Process Osseous Changes Findings and Body Measurement Factors Associated With Defined Over-riding of the Dorsal Spinous in Riding Horses. Thoracic spinous process osseous changes in horses occur due to riding-induced back compression. This study aimed to evaluate the relationship between the findings of thoracic spinous process osseous changes on radiographic imaging and conformation based on the difference in over-riding of the dorsal spinous processes in racing horses. This study included 55 sports horses. The hardness of the back muscles (the multifidus, longissimi, and latissimi collectively) was measured, and the horses were divided into two groups: low muscle hardness (n = 16) and high muscle hardness (n = 39). We conf...
Scanning electron microscopy of the nasal skin in different animal species as a method for forensic identification. The current study aims to provide a new method for the identification of animal species by using the scanning electron microscopic study on the nasal skin around the nostril. The reference databases for animal identification using traditional ways (i.e., hair and bone analyses) were somewhat available. This study was conducted on the nasal skin of seven different animal species: large ruminants (Saidi buffalo and frozen Angus cattle); small ruminants (Egyptian goat and Rahmani sheep); camels (one-hump dromedary camel); equines (African domestic donkey and Arabian horse); carnivores (farm domes...
Robustness of five different visual assessment methods for the evaluation of hindlimb lameness based on tubera coxarum movement in horses at the trot on a straight line. The evaluation of hindlimb lameness remains a major challenge in everyday clinical practice. In the absence of clear guidelines, veterinarians use different visual assessment methods for this task whose robustness is unknown. Objective: Determination of the robustness of five visual hindlimb lameness assessment methods based on the comparison of left and right tuber coxae movement. Methods: Validated mathematical hindlimb lameness model based on experimental data from the literature. Methods: Vertical movement of left (LTC) and right (RTC) tuber coxae was simulated for the range of common hind...
Semi-Automatic Segmentation of Cone Beam Computed Tomography Datasets for Volume Measurements of Equine Cheek Teeth. The volumes of equine teeth may change considerably over time for several reasons including domestication, routine dental floating, and the hypsodont and anelodont nature of the teeth. Cone beam computed tomography (CBCT) of the head is routinely performed in standing horses and, in this proof of concept study, the feasibility of measuring tooth volume from CBCT datasets was determined. The CBCT images of 5 equine cadaver cheek teeth were segmented with a software 3-dimensional (3D) Slicer using a predefined protocol, corrected manually, and re-assembled into a 3D model. Individual tooth volum...