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.
Time Attenuation Curves for Equine Intravenous Contrast Enhanced Skull CT Using the Medial Saphenous and Cephalic Veins. Intravenous (IV) contrast administration during computed tomography (CT) of the equine head is routinely performed to delineate the extent of disease and differentiate between vascular and nonvascular tissue. Current equine scan protocols are extrapolated from human and canine studies. There have been no prospective equine studies describing the optimal time to image the patient after administration of contrast or the optimal site of contrast administration. Therefore, the current postcontrast times to scan and sites of contrast administration may not be appropriate for use in horses. The obje...
Radiographic imaging of the entheses of the equine thoracic foot. An injury of a tendon or ligament of the equine foot is frequently a cause of lameness. The optimal radiographic projections delineating the entheses of five commonly injured tendons and ligaments of the foot should be described. Methods: The entheses of the collateral ligaments of the distal interphalangeal joint, the collateral sesamoidean ligaments of the navicular bone, the deep digital flexor tendon, the common digital extensor tendon and the distal sesamoidean impar ligament were isolated from a thoracic foot of three cadavers. Three standard radiographic projections (60-degree, dorsopro...
Equine coronary sinus and great cardiac vein anatomy relevant to cardiac electrophysiology. The coronary sinus (CS) and great cardiac vein (GCV) are crucial in cardiac electrophysiology and can be arrhythmogenic in humans. In horses, CS/GCV catheterisation is increasingly performed for arrhythmia diagnosis and treatment. Improved anatomical understanding of these structures is needed to clarify relationships to surrounding structures. Methods: Postmortem examinations of 64 adult warmblood equine hearts were carried out. Middle cardiac vein and vein of Marshall ostia locations were described. Right atrial myocardial sleeve (MS) length was measured from the CS ostium. In 23 horses, CS/...
Intraligamentary anaesthesia: a local anaesthesia technique in equine dentistry. The injection of a local anaesthetic into the periodontal ligament (PDL) to achieve desensitisation of the pulp, periodontium, and adjacent tissues is a well-established technique in human dentistry, particularly in paediatric patients. This approach, commonly referred to as intraligamental or intraligamentary anaesthesia (ILA), has been widely adopted due to its effectiveness and relative simplicity. The aims of the present publication were: (1) to provide a review of the literature, (2) to describe an ILA technique adapted by the authors for use in equine dentistry, and (3) to evaluate this ...
Umbilical cord torsion abortion: the gross and histological features of affected umbilical cords and fetal membranes. Umbilical cord torsion (UCT) is the most frequent pathology of the equine umbilical cord (UC) and a prominent cause of abortion, yet objective data on its features remain limited. This study compared UCT with clinically normal pregnancies (CNP) to (i) identify gross and histological features of the UC and fetal membranes, (ii) determine whether UCT is associated with fetal growth restriction, and (iii) rule out infectious aetiologies. Gross and histological features of the UC, chorioallantois and amnion were compared between groups. Fetal weight and crown-rump length were analysed relative to ...
Endoscopically assisted transcutaneous placement of a balloon catheter in the medial guttural pouch compartment of the horse: A surgical approach to local treatment. To describe and report clinical outcomes after transcutaneous guttural pouch (GP) catheterization (TGPC) in standing horses. Methods: Ex vivo study and case series. Methods: One cadaver head, records of 10 normal horses and 14 horses treated with TGPC. Methods: Relevant anatomical landmarks were determined through dissection of one cadaveric specimen and 10 normal radiographic studies. Records of horses diagnosed with empyema or mycosis and treated with standing TGPC were reviewed for complications that occurred during or after the operation. Results: Ex vivo and radiological studies identifie...
Computed tomographic myelography of the cranial cervical vertebral column in unaffected Warmblood horses – comparison of transverse vertebral ratios in the flexed and neutral cranial cervical vertebral column. Computed tomographic myelography (CTM) is diagnostic for extradural spinal cord compression but knowledge about vertebral ratios from transverse images in flexion and normal position of unaffected horses is lacking. Objective: To compare the ratios of the cross-sectional areas (CSAs) of the spinal cord, the vertebral canal and of the contrast enhanced dural tube on transverse CTM images at C3-C4 in neutral and flexed positions in unaffected Warmbloods. Methods: CTM was performed in 13 neurologically unaffected Warmbloods in neutral and flexed cervical vertebral column positions. Ratios were ca...
Could “wild horses” drag you away? Quantifying muscular architecture in the forelimbs of extant, non-domestic equids (Perissodactyla: Equidae). Equid evolution is characterized by a high diversity of extinct species and morphologies, whereas extant equids share a superficially similar, monodactyl morphology. This inferred musculoskeletal similarity of modern equid limbs remains unexplored, and it is often assumed that domestic horse limbs are representative for wild equids (e.g., zebras, onagers, etc.). Our aim was to quantitatively describe the muscle architecture and arrangement of all forelimb muscles in extant wild Equus species to test this assumption, and investigate any differences between the species. We hypothesized that ther...
Radiographic measurements of Miniature Horse and Miniature Pony Feet. Reliable assessment of foot conformation is essential for podiatric management in Miniature Horses and Ponies, yet reference ranges and the reliability of radiographic measurements remain poorly defined. Objective: This study quantified radiographic measurements of foot conformation in sound, skeletally mature Miniature Horses and Ponies and evaluated their agreement, reliability, and precision. Methods: Standardised lateromedial and dorsopalmar/plantarodorsal radiographs were obtained from 30 Miniature Horses and Ponies. Two observers took 60 measurements from 10 sets of projections on three ...
Computed Tomographic Assessment of Normal Ocular Dimensions and Densities in Cadaveric Horses (Equus ferus caballus). This study aimed to characterize the computed tomographic (CT) dimensions and contrast attenuation properties of the equine eye. CT scans from 21 horses without ocular abnormalities were analyzed to obtain detailed ocular measurements and attenuation values. In addition, cranial measurements, such as nasal-occipital length and zygomatic width, were incorporated to explore potential anatomical relationships between the skull and intraocular structures. Although most correlations between cranial and ocular parameters were weak, statistically significant associations-particularly those involving ...
Arterial distribution to the tensor fasciae antebrachii muscle: a study in dogs, cattle, pigs, and horses. Arterial distribution to the tensor fasciae antebrachii (TFA) muscle is little described in the veterinary literature. In this study, we investigated TFA vascularity intra- and inter-specifically, using specimens obtained from dogs, cattle, pigs, and horses at necropsy. Canine TFA specimens showed vascularity from the collateral ulnar artery in all cases, and from the thoracodorsal artery in some cases, with no brachial or deep brachial arterial vascularity. Bovine TFA specimens showed vascularity from the thoracodorsal artery. All porcine TFA specimens showed deep brachial arterial vascularit...
Ultrasound-guided versus blind intercostal nerve injection in equine cadavers. To describe the detailed anatomy of the equine thoracoabdominal region and to compare the accuracy of ultrasound-guided versus blind intercostal nerve injection techniques, targeting the thoracic intercostal nerves (T12-T18) in equine cadavers. Methods: Randomized, blinded, cadaveric study. Methods: Eight fresh adult equine cadavers. Methods: Eight horse cadavers were used: one in phase I (436 kg; 4 years old) for anatomic landmarks identification and seven in phase II [420 (317-560 kg); 16 (3-22 years old) [median (minimum-maximum)] for comparative study. In phase I, dissections were performe...
Ultrasonography and shear wave elastography of equine skin: a preliminary study. To noninvasively characterize skin thickness and elasticity in healthy horses using B-mode ultrasound and shear wave elastography (SWE) and to verify whether there are differences between the skin of stabled and outdoor horses. Unassigned: 10 clinically healthy horses were enrolled in this study. Five animals were housed exclusively indoors (indoor group), and 5 had temporary or permanent access to an outdoor environment (outdoor group). All horses underwent bilateral ultrasonographic examination of 3 anatomical regions: neck, withers, and girth region caudal to the elbow. Skin thickness was a...
Mechanical characterization of the equine linea alba and finite element modeling of suture patterns effects on its closure. Postoperative incisional complications are common in horses following abdominal surgery, which typically involves an incision through the abdominal wall along the linea alba. The linea alba is a fibrous band running in the craniocaudal direction along the ventral abdomen. This incision is closed with sutures, where the choice of suture pattern and surgical technique has shown to influence the rate of complications. Therefore, this study investigated how different suture patterns and variations influence the stresses in the tissue by combining experimental and computational biomechanics. The me...
Cronodent I, 3D interactive manual for self-learning of the dental chronology of equines. One of a veterinarian's routine tasks is animal identification, with age being a crucial factor in the identification and evaluation of individuals. Knowledge of the morphological changes in animal dentition used to determine their age is essential in veterinary education. Today's students increasingly prefer innovative learning tools that incorporate 3D anatomical models over traditional 2D resources. As part of a teaching innovation project at the University of Córdoba, Spain, new educational materials were developed to aid students in identifying the age of animals using 3D images of equin...
Ultrasonographic Assessment of Caudal Vena Cava Collapsibility Index, Caudal Vena Cava-to-Aorta, and Femoral Vein-to-Artery Ratios in Healthy Sedated Adult Horses. (1) Background: Ultrasonography of major vessels helps evaluate fluid status and responsiveness in critical human and canine patients. Aims: transrectal and inguinal ultrasonography of caudal vena cava (CVC), aorta (Ao), and femoral artery (FA) and vein (FV) in horses; calculate CVC collapsibility index (CI CVC) and vein-to-artery ratios; compare B- and M-mode; and evaluate repeatability and reproducibility. (2) Methods: B-mode and M-mode video loops were recorded twice by transrectal (Ao, CVC) and inguinal ultrasonography (FV, FA) by two operators on 17 healthy, sedated adult horses. Diameter...
Complications of Respiratory Surgery in the Horse. Respiratory surgery and procedures typically focus on conditions of the upper airway that restrict airflow at rest or exercise. This article focuses on respiratory anatomy and common surgeries of the trachea and larynx in horses. The trachea serves as the airway conduit from the larynx to the bronchi. A variety of upper airway disorders can lead to obstruction and in these instances, tracheotomy is typically utilized to bypass these obstructions and maintain airway patency. Emergency and permanent tracheotomy procedures are discussed. Other common upper airway operations, such as laryngotomy, ...
Evaluation of maturation-related changes in maxillary sinus diameter and cheek teeth positioning relative to the maxillary sinus in the Dareshuri horse. Dareshuri horses are the predominant breed in Fars Province, Iran. Although disorders affecting their maxillary cheek teeth and maxillary sinuses are relatively common, limited fundamental data are available on the dimensions and relationships of these structures at different ages. Given the significant anatomical changes in the heads of young horses as they mature, this study aimed to evaluate age-related changes in the position and anatomical relationships of individual maxillary cheek teeth within the rostral and caudal maxillary sinuses (RMS and CMS, respectively), as well as changes in th...
Tenoscopically guided proximal digital annular ligament desmotomy for the treatment of proximal digital annular ligament desmitis. To describe a tenoscopically guided technique for desmotomy of the proximal digital annular ligament (PDAL). Methods: Ex vivo study and clinical case series. Methods: A total of 10 normal cadaver equine hindlimbs and five clinical cases of PDAL desmitis. Methods: The digital flexor tendon sheath (DFTS) was approached via a lateral basisesamoid portal and a palmar/plantar annular ligament (PAL) desmotomy was performed to improve maneuverability in the DFTS. Additional proximolateral and distal midline instrument portals were created to facilitate transection of the proximolateral attachment, th...
Intrinsic characteristics of donkeys that affect drug treatment. Donkeys have contributed to the development and livelihoods of humans for almost 7,000 years. They have been used for traction and transportation, kept as pets, utilized in animal-assisted therapies, or farmed as food-producing animals. Over the past two decades, significant progress has been made in bridging the knowledge gap in veterinary medicine between donkeys and horses. Veterinary practitioners are now more aware that donkeys have important behavioral, anatomical, and physiological characteristics that distinguish them from horses. These peculiarities should be considered when treating ...
Correction: Association between radiographic equine distal phalanx characteristics and absence, presence and type of horseshoes. [This corrects the article DOI: 10.3389/fvets.2025.1598038.].
Horse vision through two lenses: Tinbergen’s Four Questions and the Five Domains. To improve human-horse interactions and reduce the risk of injury, it is essential to adopt an equi-centric perspective that prioritizes how horses perceive their environment. This review focuses on the equine visual system, both because it is the most studied of the horse's senses and because misunderstandings about how horses see can lead to unsafe or unsustainable handling. By applying two complementary frameworks, namely Tinbergen's Four Questions and the Five Domains model, we examine equine vision from both a biological and a welfare-oriented perspective. We explore the anatomical and fu...
Motion Coupling at the Cervical Vertebral Joints in the Horse-An Ex Vivo Study Using Bone-Anchored Markers. The influence of soft tissue structures, including ligaments spanning one or more intervertebral junctions and the nuchal ligament, on motion of the equine cervical joints remains unclear. The present study addressed this using four post-mortem horse specimens extending from head to withers with all ligaments intact. Three-dimensional kinematics was obtained from markers on the head and bone-anchored markers on each cervical and the first thoracic vertebra during rotation, lateral bending, flexion and extension of the whole head, and neck segment. Yaw, pitch, and roll angles in 8 cervical join...
Morphological and morphometric characterization of the aorta of Brazilian horses (Equus ferus caballus, Linnaeus-1758): Comparative analysis of the aortic bulb and ascending aorta. We examined 52 horse aortas to characterize the morphological aspects of the aortic bulb wall and the ascending aorta. The morphometric data were analyzed using ImageJ®-Fiji 1.5 software. The Tunica intima was composed of endotheliocytes with scarce cytoplasm and ellipsoid nuclei, supported by a collagenous subendothelial stratum. The Tunica media was composed entirely of fascicles of vascular smooth muscle cells interspersed with bundles of collagen fibers and elastic lamellae, characterizing the aortic medial lamellar unit. The Tunica adventitia consisted of two distinct sub-layers: the ext...
Histological Study of the Normal Proximal Third Interosseus Muscle Enthesis in the Equine Pelvic Limb. In human medicine, the enthesis, or tendon-to-bone insertion, is generally considered a linked entity or 'enthesis organ' and plays a crucial biomechanical role. This study aimed to histologically assess the equine proximal third interosseus muscle (suspensory ligament) enthesis in 10 pelvic limbs from 7 horses. The area of the proximal third interosseus muscle enthesis was divided into 6 compartments based on post-mortem computed tomography and prepared for histology using haematoxylin/eosin and trichrome staining. The proximal third interosseus muscle enthesis showed a fibrocartilaginous nat...
Tendon/Ligaments: Structure and Composition. The mid-metacarpal SDFT, intrasynovial DDFT and suspensory ligament are frequently injured soft tissues in the equine athlete. The mid-metacarpal SDFT exhibits a hierarchical structure and encounters repetitive strains at its functional limit. The intrasynovial DDFT possesses fibrocartilage where opposing bony surfaces to facilitate resistance-free gliding and contains chondrocyte-like cells embedded in a proteoglycan-rich ECM. While suspensory ligament enthesis injuries are common, collagen and non-collagen ECM structure-function specializations at the bone-ligament interface are understudied...
Pathophysiology of penetrating captive-bolt stunning of horses. There has been limited research into the effectiveness of penetrating captive bolt (PCB) for stunning horses () at slaughter. This study observed 100 horses at a commercial abattoir in Mexico, stunned using pneumatic PCB. Animals were assessed at the time of stunning and immediately after for signs of effective/ineffective stunning and shot positioning, with macroscopic gross brain pathology conducted to determine brain trauma. Twenty-five percent (25/100) received more than one shot and 28% (28/100) displayed behavioural signs of ineffective stunning. Of these 28 animals, all had deviations o...
Inspiratory and expiratory tracheal pressures during high-intensity exercise in harness racehorses. Exercise-related upper respiratory tract (URT) disorders are common in racehorses. Objective assessment of URT mechanics is essential to quantify degrees of obstruction caused by URT disorders identified upon dynamic endoscopy. Objective: To establish reference values for inspiratory and expiratory tracheal pressures (cmHO) during high-speed treadmill endoscopy in harness racehorses with clinically normal URTs. Methods: Prospective observational study. Methods: Tracheal pressures were measured in harness racehorses (Standardbreds and Norwegian-Swedish coldblooded trotters) in which no URT abno...
Normal MRI features of the manica flexoria in horses and evaluation of the anatomic variability between forelimbs and hindlimbs. Manica flexoria tears are increasingly recognized as a cause of lameness in horses resulting in a need for improved pre-operative diagnosis. Partial tears are difficult to pre-operatively diagnose and thus research for diagnostics of manica flexoria tears has been seen in increasing frequency over the past decade, though a deficit of information exists for the features of this structure on MRI, which is best suited for evaluation of soft tissues. The goal is to perform an observational study on the morphometry of the normal manica flexoria prospectively and describe it retrospectively on MRI. ...
Non-contrast enhanced visualization of the equine foot vasculature in a cadaver model using time-of-flight sequence. The objective of this study was to establish a non-contrast enhanced MR angiography (NC-MRA) sequence for the equine foot (EF) using a post-mortem angiography model. Unassigned: Time-of-flight (TOF) sequences were tested using variable parameter settings and 3 slice orientations during vascular perfusion of frozen-thawed cadaver EF with paraffine oil. Transverse and dorsal orientations were planned perpendicular or parallel to the sublamellar vascular plexus at the dorsal aspect of P3, or approximately perpendicular to the coronary plexus. Visibility of the coronary plexus, sublamellar plexus,...