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.
Equestrian-related maxillofacial injuries-a five-year retrospective review. Equestrian-related activities inherently involve the risk of serious injury. There are few reports of maxillofacial injury patterns and management arising from equestrian activities in the literature. Objective: To investigate maxillofacial fracture presentations at a tertiary trauma centre to identify injury profiles of patients who have sustained equine-based injuries over 5 years. Methods: This work involved a retrospective review of all trauma presentations to our unit over 5 years. The data collected included patient demographics, injury mechanisms and patterns, and management of fractu...
Usefulness of a Computer-Aided Learning Module for Teaching Radiology of the Equine Foot to Clinical Veterinary Students. Lameness in horses resulting from foot pathology is very common. When investigating the cause of a lameness localised to the foot, the first step is most frequently radiographic imaging. Therefore, being able to identify normal anatomy and recognise pathology on radiographs is important for a veterinary medicine student to learn. Computer-aided learning (CAL) is becoming increasingly utilised in the teaching of students on medicine-related courses, especially post-COVID where online learning has been continued in hybridisation with in-person teaching.In this study, a low-cost CAL module was cr...
Computed tomographic myelography of the cranial cervical spine in Warmblood horses with no spinal pathology-Inter- and intravertebral ratios and distribution of contrast columns in neutral and flexed cervical spine. Computed tomographic myelography (CTM) and radiographic myelography (RxM) are diagnostic for extradural spinal cord compression, but knowledge about the contrast distribution in flexion and normal position of nonaffected horses is lacking. Objective: (1) To determine the inter- and intravertebral ratios at C3-C4 of CTM in neutral and flexed positions in Warmbloods. (2) To compare the diameters of the spinal cord and the contrast columns at C3-C4 between neutral and flexed positions in CTM and RxM. (3) To evaluate the variability of measurements. Methods: Terminal in vivo method-comparison stud...
Physiological response to weight carrying and associations with conformation traits in Icelandic horses used for tour riding. Weight carrying capacity is an important trait in riding horses and it may be associated with conformation. This study examined the physiological response to a ridden incremental weight carrying test in 16 adult Icelandic horses used for tour riding. Horses carried 20% (BWR20%), 25% (BWR25%), 30% (BWR30%) and 35% (BWR35%) of their body weight (BW) in tölt (~ 5.7 m/seconds, 640 m/step), and associations with body measurements and back conformation (score) were examined. Horses were divided into two groups (narrow or broad back) and body measurements were collected. Plasma lactate was analy...
Current Practices and Considerations in Therapeutic Farriery for Equine Tendon and Ligament Injuries. The overall objective of therapeutic farriery for equine tendon and ligament injuries is to provide a biomechanical environment conducive to healing by limiting excessive strain on the injured structure. With an understanding of equine limb anatomy and the pathophysiology of tendon/ligament injuries, the rationale used in therapeutic farriery for soft tissue injuries of the distal limb is quite logical. Through therapeutic farriery, foot manipulation is used to reduce the tension on the injured tendon(s) or ligament(s).
Structure Function Relationships in the Aging Superficial Digital Flexor Tendon: Implications for Injury. The high stresses and strains experienced by the superficial digital flexor tendon (SDFT) make it prone to age-related injury. The SDFT exhibits cellular and structural specializations, localized to the interfascicular matrix (IFM), enabling it to resist its extreme mechanical environment. With aging, these specializations are lost, impacting the ability of the tendon to withstand repeated loading. Within the IFM, there is loss of mechanical properties and organization accompanying cell senescence and a decreased resolution of inflammation. Developing therapeutics to reverse these changes may,...
Diagnosis and Minimally Invasive Surgical Treatment for Enhancing Intrathecal/Intrasynovial Tendon Injuries. Intrathecal and intrasynovial tendon and ligament injuries can result in extrusion of tendon/ligament fibers, granuloma, and adhesion formation that not only impairs healing of the original injury but can create new injuries that negatively affect adequate healing and return to athletic work. In these cases, endoscopic evaluation and debridement, not only of the lesion, but also any other secondary injury present, can enhance the healing of the tendon or ligament and improve the athletic prognosis. Careful planning of the approach, positioning, instrumentation, and thorough knowledge of the an...
Computed Tomography of the Hyoid Apparatus in Equine Headshaking Syndrome. Headshaking is a common condition in horses, most cases are presumed idiopathic/trigeminal-nerve mediated. Diagnostic work-up of a headshaking horse may involve computed tomography (CT) of the head to exclude causative structural pathology. The relevance of the presence and severity of hyoid apparatus findings at CT to headshaking is unknown. A retrospective analysis of CT changes in the hyoid apparatus in horses was carried out. Comparisons were performed between horses with signs of headshaking and a control population and a subgroup of horses with signs of headshaking and no other 'likely...
Complementary Radiographic Projection for Evaluation of the Conchal Sinuses and Bullae in Horses. Radiographic examination of the skull is a well-established and indispensable procedure for the diagnostic evaluation of dental and paranasal sinus disorders in horses. Complementary projections make significant contributions to radiographic diagnosis in nasal conchae disorders. This article describes a complementary radiographic projection designed for the evaluation of the conchal sinuses and bullae in horses. Six equine cadaveric heads were used. Specimens were dissected, and openings were created in the ventral and dorsal nasal conchae for the introduction of radiopaque material. The new r...
Sinonasal angiofibroma in a horse. A 34-year-old Haflinger gelding presented with a unilateral, expansile, intranasal mass that regrew after partial excision. After euthanasia, a large pedunculated mass that originated from the left caudal maxillary sinus and obliterated the left nasal cavity was seen by radiological and macroscopic examination. Histopathology revealed a poorly cellular, expansile, well-vascularized neoplasm composed of a loosely arranged meshwork of spindle cells and collagen fibres. Spindle cells were immunopositive for alpha-smooth muscle actin and occasionally for vimentin, whereas endothelial cells immunol...
Morphological variations of the interatrial septum and potential implications in equine cardiology. The interatrial septum morphology, shaped by the septum primum and secundum fusion, results in the formation of the fossa ovalis (FO) and its limbus. Incomplete fusion can lead to a patent foramen ovale (PFO), while complete fusion may produce septal ridges and pouches (SPs), with SPs in humans linked to ischemic stroke and atrial arrhythmias. In horses, atrial tachycardia and fibrillation often originate near the FO. This study examines adult equine interatrial septum morphology to enhance understanding the region and guide electrophysiological interventions for equine cardiac arrhythmias. Po...
Analysis of different techniques for injection of the interspinal space in horses. Impingement of spinous processes (SPs) is commonly diagnosed in the equine athlete. For diagnostic and therapeutic purposes, local injections are performed at the level of the space between adjacent spinous processes in affected horses. Objective: To assess the accuracy of different techniques for the local injection of the interspinal space in the equine thoracolumbar spine. Methods: Ex vivo experimental study. Methods: Equine thoracolumbar spine specimens were used to compare three techniques for needle insertion (midline; bilateral abaxial; unilateral oblique), two needles (20G-1½″; 20G-...
INJECTION OF THE INSERTION OF THE COLLARAL LIGAMENT OF THE DISTAL INTERPHALANGEAL JOINT IN STANDING HORSES USING THE PALMAR RADIOGRAPHIC-GUIDED APPROACH. Injury to the collateral ligament (CL) of the distal interphalangeal joint (DIPJ) is recognized as a source of lameness in horses. Intralesional injection has been advocated to increase return to performance. This study was a proof-of-concept study in standing horses to evaluate success of a palmar radiographic-guided approach for injecting insertions of the DIPJ CLs previously described in cadaver limbs. Horses were sedated, nerve blocked, and placed on wooden blocks with the limb to be injected staggered approximately 20cm cranially to the other limb. The DIPJ CL insertion was injected, usin...
Internal carotid artery dolichoarteriopathies in the horse: An endoscopic and anatomic study. Endoscopy of the guttural pouches in neonatal foals occasionally reveals atypical aspects in the course of the extracranial internal carotid arteries (ICAs) that are hardly seen in adult horses. While in veterinary medicine the data available on the presence of these anomalies in domestic mammals are limited and incomplete, in human medicine the morphological aspects of the ICAs have been the subject of extensive studies. Anomalies in the course and geometry of ICAs are commonly defined as dolichoarteriopathies, and should be classified as tortuous, kinked or coiled. To document whether the an...
A dorsal ultrasound-guided approach to perineural injection of the sixth and seventh cervical spinal nerves in horses is accurate and does not result in epidural placement. To determine the accuracy of a dorsal ultrasound-guided approach for perineural injection of the sixth and seventh cervical spinal nerves (CSNs) with the use of a clinically relevant volume of injectate (2 mL). We hypothesized that the majority of injections would result in identification of contrast solution in the intervertebral foramen (IVF) on CT and corresponding methylene blue dye staining of the CSN on postmortem evaluation, and distribution of injectate into the epidural space would not occur. Unassigned: 7 horses donated to the University of Pennsylvania New Bolton Center for euthanas...
Computed tomographic measurements in 110 front hooves of non-lame Thoroughbred racehorses and Warmblood showjumpers. There are no published reference ranges on computed tomographic (CT) hoof wall and sole measurements. Objective: To establish reference ranges for CT measurements of the hoof wall and sole in non-lame horses, and to investigate associations between measurements and signalment, laterality, and medial or lateral sides. Methods: Retrospective, cross-sectional study. Methods: Soft tissue reconstructions of fan-beam CT studies of 110 front feet of 56 non-lame horses (30 Thoroughbred racehorses, 26 Warmblood showjumpers), performed in non- to semi-weightbearing positions, were analysed. Hoof wall th...
Evidence of glycan mosaicism in the equine oviduct. We report a lectin histochemical study of oviductal ampulla and isthmus of thirteen mares euthanised at anestrus (1), estrus (5), 1-day post-ovulation (5) or diestrus (2). Staining with a panel of 5 lectins recognizing N-Acetylgalactosamine (GalNAc) residues revealed mosaicism in glycan expression in some specimens of ampulla and isthmus, peaking at estrus and 1-day post-ovulation (ov+1). In the ampulla, this presented as positively stained areas of both ciliated and non-ciliated cells in otherwise negatively-stained ampullae, ranging from small foci (diestrus) to areas up to 200 microns in le...
Gross anatomy, computed tomographic contrast tenography, and needle endoscopy of the equine medial digital flexor tendon sheath. To investigate the computed tomography (CT) and gross anatomy of the equine medial digital flexor tendon sheath (MDFTS), and the endoscopic anatomy and approach to the MDFTS. Methods: Ex vivo experimental study and one clinical case. Methods: Twelve clinically normal cadaveric hindlimbs. Methods: Dissection, native and contrast CT scans were conducted to evaluate the anatomy of the MDFTS. Based on these findings, the portal locations for the endoscopic approaches were determined. Six hindlimbs were used in the pilot phase and another six limbs were selected for the main study. Endoscopic image...
Major Salivary Gland Examinations of the Donkey (Equus asinus) Using Sectional Anatomy, Computed Tomography and Magnetic Resonance Imaging. Visualizing the major salivary glands (MSGs) in domestic mammals using plain radiology and identifying damaged their structures is impossible. To accurately display MSGs, the knowledge of normal sectional imaging anatomy is essential for veterinarians, aiding them significantly in identifying the exact relations and position of MSGs; however, no reports on the MSGs sectional imaging anatomy in this species have been made. Objective: This study aimed to evaluate computed tomography (CT), magnetic resonance imaging (MRI) and gross sections of MSGs. Methods: Seven healthy adult donkeys were used ...
Equine cadaveric study suggests tibial and fibular nerve block is feasible with a single ultrasound-guided injection via a caudocranial midfemoral approach. To describe anatomical references and sonoanatomy of an echo-guided injection for blocking the tibial and common fibular nerves with the use of a caudocranial midfemoral approach and to evaluate dye spreading in horse cadavers. Unassigned: 1 horse cadaver preserved in glycerin was used for the anatomical study, and 14 fresh horse cadavers were used for the dye spreading study. The experimental procedures were conducted on the first cadaver on March 25, 2021, and on the last cadaver on October 5, 2022. A glycerin-preserved horse cadaver's pelvic limb was dissected to identify anatomical landmar...
Resistivity and Pulsatility Indexes Renal Values Do Not Differ When Obtained from Abdominal or Transrectal Approaches in Healthy Horses. Early detection of renal deficient function is imperative for the success of treatments and determining prognosis. In horses, a renal ultrasound can be performed through the abdominal wall (TA) or transrectally (TR), being an important tool for the evaluation of the kidneys. Besides renal morphology, resistivity (RI) and pulsatility indexes (PI) may be early tools to detect renal injury as they reflect arterial compliance. Twenty-nine healthy adult horses were sonographically evaluated by TA and TR approaches, measuring RI and PI on both kidneys. The mean values from the TA for RI and PI in th...
Comparison of a dorsolateral approach and a dorsomedial approach to access the medial malleolus of the distal tibia in horses. To determine the utility of a dorsolateral arthroscopic approach to the tarsocrural joint (TCJ) to examine and surgically access the medial malleolus (MM) and compare this to the standard dorsomedial approach to the MM. Methods: Experimental cadaver study. Methods: Six pelvic limbs from four adult horses. Methods: Arthroscopic examination of the dorsal aspect of the TCJ was performed followed by the dorsomedial and dorsolateral surgical approaches to the MM, in randomized order on cadaver limbs (n = 6). The dorsomedial approach involved placing the arthroscope and instrument in the dorsome...
Computed Tomographic Tenography of the Equine Carpal Flexor Tendon Sheath. Exploratory tenoscopy is considered the gold standard technique to identify intrathecal pathology of the equine carpal flexor tendon sheath (CFTS). Preoperative diagnosis allows for more precise prognostication and surgical planning, potentially associated with improved surgical outcomes. This prospective, descriptive, anatomical study aimed to describe the anatomy of the equine CFTS using noncontrast and contrast CT in clinically normal cadaver limbs. Ten pairs of equine forelimbs free of gross external abnormalities were examined from mid-antebrachium to distal metacarpus. Specimens initiall...
Preoperative computed tomography imaging for accurate diagnosis and surgical planning in equine cranial disorders: two case reports of congenital malformations. Computed tomography (CT) offers high-resolution, three-dimensional imaging, making it particularly valuable for assessing complex structures, such as the head, especially when conventional radiography and endoscopy are insufficient for a definitive diagnosis. Herein, we present two cases of equine cranial disorders resulting from congenital malformations. In case 1, which had a dentigerous cyst, CT images confirmed the location of the ectopic tooth within the skull and a detailed fistula tube. In case 2, which had temporohyoid osteoarthropathy, CT examination revealed that the stylohyoid bone ...
Casting techniques of equine hand and foot synovial cavities for the development of teaching models. Horse joints are common sites of injury, orthopedic issues, and surgical and clinical interventions. For this reason, a thorough understanding of joint anatomy, including the boundaries of their recesses and their relationships with other structures of the locomotor apparatus, is essential. This study aimed to develop cast anatomical models of the synovial structures of the equine hand and foot, compare different casting materials and visualization methods, and identify the most suitable technique for enhancing the understanding of equine limb arthrology. Additionally, an anatomical descriptio...
Characterising equine abdominal lipomata: Can histological features improve the understanding of pathogenesis and risk? Strangulating lipomata are the most common cause of small intestinal strangulating obstruction. Evaluation of histological features of pathological and non-pathological lipomata, and the histological properties of omental and retroperitoneal fat have not been described. Objective: To characterise histological features of equine abdominal lipomata, omental and retroperitoneal adipose tissue, and associations between them. Methods: Prospective observational anatomic (gross and histological). Methods: Horses undergoing emergency laparotomy for management of abdominal pain in a single hospital wer...
Measuring Noseband Tightness on the Lateral Aspect of the Horse’s Face. Measuring tools designed to objectively determine equine noseband tightness are inserted on the dorsal nasal planum in a rostro-caudal direction. The lateral aspect of the horse's head has several areas where minimal soft tissue intervenes between the skin and underlying bone, which makes them potentially useful sites for measuring noseband tightness. One hundred horses were fitted with a snaffle bridle with a cavesson, Swedish or dropped noseband in random order. The tightness of each noseband type was adjusted sequentially to 2.0, 1.5, 1.0, 0.5 and 0.0 finger-equivalents using an ISES Taper ...
The Value of a Modified Posterior Thigh Flap with Z-Plasty for Reconstruction of Ischial Tuberosity Pressure Ulcers: A Retrospective Single Center Analysis. Pressure ulcers are a persistent and growing challenge in modern medicine, with prevalence rates ranging from 3.4% to 32.4% globally. Demographic changes suggest an increasing number of patients at risk, emphasizing the need for effective prevention and advanced treatment strategies. These ulcers, particularly stages III and IV, often require surgical intervention due to severe tissue damage. Among the surgical options, the Posterior Thigh Flap has emerged as a reliable fasciocutaneous flap, frequently referred to as a "work-horse flap", for defect coverage in the ischial region. To improve ou...
The Challenge of Defining Laterality in Horses: Is It Laterality or Just Asymmetry? The defining characteristic of laterality is the dominance of one side of the brain controlling specific functions of paired organs or on one side of the body. Structural and functional asymmetries are ubiquitous in horses and range from anatomical features (e.g., the length of long bones) to the gathering of sensory information (e.g., which eye is used to observe unfamiliar scenes) and motor functions (e.g., left-right differences in locomotion). There is a common tendency to assign observed structural or functional asymmetries to lateralization, which often involves more than a simple left-r...
Abdominal Ultrasonography in Healthy Female Standard Donkeys. Knowledge of the normal ultrasound anatomy in the donkey is essential to understand pathological changes and to reach an early diagnosis, considering the "dullness" and stoicism of these animals in pain manifestations. The aims of this study were to document which abdominal viscera could be identified using a transcutaneous ultrasonography technique under field conditions in unsedated, standing donkeys to determine where the different abdominal structures could be easily displayed and to describe any variation that occurred between different donkeys and horses. In this work, the manual techniq...