Omneity® Pellets
All-In-One Vitamin & Mineral Pellet
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.
Histologic features of the carotid artery trifurcation in thoroughbreds. The common, external, and internal carotid and occipital arteries were examined histologically at the trifurcation of the common carotid arteries in 13 Thoroughbred foals (0 to 30 days old) and 64 Thoroughbred adults (2 to 4 years old). Calcification in the media of the common carotid and external carotid arteries was observed in 3 of the 13 foals and in 30 of the 64 adult horses. Calcification resembled that seen in Mönckeberg's arteriosclerosis in human beings, the cause of which is unknown.
Levator nasolabialis muscle transposition to prevent an orosinus fistula after tooth extraction in horses. The ventral part of the levator nasolabialis muscle was transposed to the alveolar defect after sinusotomy and tooth extraction in five normal horses and six horses with a tooth root abscess and sinusitis. In the normal horses at weeks 6, 10, 14 and 18, the transposed muscles remained viable and were incorporated into the recipient sites, and orosinus fistulae did not form. Histologically, there was a progressive transition from muscle to fibrous tissue. There was no facial deformity or loss of nasal function at the donor site. A localized abscess was associated with incomplete removal of toot...
Corticocancellous bone biopsy from the 12th rib of standing horses. Unicortical corticocancellous bone biopsy specimens 4.5 mm and 6.5 mm in diameter were obtained without long-term complications from the 12th rib in eight standing horses. However, the bone specimens were unsuitable for histologic or histomorphometric evaluation. In in vitro comparisons of biopsy specimens 6.5 mm and 12 mm in diameter, and of unicortical and transcortical biopsy specimens, 12 mm transcortical specimens yielded the most cancellous bone. Transcortical bone biopsy specimens 12 mm in diameter were obtained from eight horses by using power-assisted trephination. The surgical proced...
Granulosa-theca cell tumor associated with an ovulation fossa and normal ovarian stroma in a mare. A granulosa-theca cell tumor was found in an ovary that had an ovulation fossa and normal ovarian tissue. The ovary was removed from a mare with a history of ovarian enlargement and behavioral changes. The affected ovary had a multicystic appearance on ultrasonographic examination performed before surgery, and an ovulation fossa was not palpable on examination per rectum. However, during surgery, the affected ovary was found to be within normal size limits, with an enlargement on 1 pole, and to contain an ovulation fossa. Atrophy of the infundibulum of the affected ovary helped to confirm the ...
Arthrographic analysis of communication between the tarsometatarsal and distal intertarsal joints of the horse. The intra-articular anatomy of 103 equine tarsi was studied by contrast radiography with image intensification and computerized tomography. There was communication between the tarsometatarsal and distal intertarsal joints in 21 of 55 (38%) interpretable tarsometatarsal arthrograms, and in 11 of 48 (23%) interpretable distal intertarsal arthrograms. The difference was not significant. The volume of contrast agent and the pressure of injection did not correlate with communication. Forced injection caused subcutaneous leakage of contrast medium but not communication. Communication occurred via th...
Crystallographic studies of a calcium binding lysozyme from equine milk at 2.5 A resolution. The crystal structure of a calcium binding equine lysozyme has been determined at 2.5 A resolution by means of molecular replacement. The energy minimized equine lysozyme as the starting model, was refined with the molecular dynamics program, X-PLOR, and the R factor of the current model was found to be 24% without any water molecules. The conformation of the calcium binding loop is similar to that of alpha-lactalbumin. The profiles of backbone atomic displacements throughout the lysozyme and alpha-lactalbumin superfamilies are comparable as well as their homologous tertiary structures.
Paralaryngeal accessory bronchial cyst as a cause of laryngeal haemiplegia in a horse. LARYNGEAL haemiplegia is common in horses and most often
involves the left haemilarynx (Baker 1983; Haynes 1984).
Although specific processes have been incriminated in the
pathogenesis of laryngeal haemiplegia, most cases involve an
idiopathic distal axonopathy of the recurrent laryngeal nerve. The
purpose of this report is to describe a case of laryngeal
haemiplegia associated with an anomalous respiratory cyst. A
description of the lesion, method of surgical repair of the
laryngeal collapse and a proposed term to describe the
abnormality based on pathological and functional consider...
Attempted reinnervation of the equine larynx using a muscle pedicle graft. Laryngeal hemiplegia was induced in 4 ponies via a left recurrent laryngeal neurectomy. Reinnervation of the denervated left cricoarytenoideus dorsalis muscle was then attempted using a muscle pedicle graft from the right cricoarytenoideus dorsalis muscle. In 3 ponies there was no return of abductor function and failure of graft survival. In the fourth pony there was return of abductor function along with survival of the muscle bridge, however, there was evidence of reinnervation across the neurectomy site. Muscle-to-muscle neurotization of the paralyzed equine larynx, utilizing the cricoaryte...
Determination of the early age of onset of equine recurrent laryngeal neuropathy. 1. Muscle pathology. The age of onset of equine recurrent laryngeal neuropathy has not been ascertained, although the clinical condition of left laryngeal hemiplegia ("roaring") has been recognized for centuries. The purpose of this study was to evaluate the laryngeal muscles of draft horse foals for the presence of fiber-type grouping, indicating denervation and reinnervation, and to determine if histological evidence of recurrent laryngeal neuropathy was present. Abductor and adductor laryngeal muscles from the left and right sides were collected immediately after euthanasia from male draft horse foals, six less...
Pathways of lymph flow through intestinal lymph nodes in the horse. In the horse, several thousand lymph nodes receive lymph from the intestine, part of which is very large and contains microorganisms that enable the animal to utilize refractory dietary constituents such as cellulose. The aim of this study was to describe the pathways by which lymph is delivered into, traverses, and is drained from these lymph nodes. These pathways were studied with either Microfil or methacrylate casting materials and with light and electron microscopy. The afferent lymphatic vessel delivering lymph into one of the nodes divides over the capsular surface and within trabeculae...
Elbow extensor muscles of the horse: postural and dynamic implications. Based on histochemical and immunohistochemical evidence, horse elbow extensor muscles are composed of two morphologically distinct muscle groups. The long and lateral heads of the triceps brachii are large, predominantly type II (presumed fast) muscles. The long and lateral heads of the triceps together account for 96% of the weight of the elbow extensors (long head of triceps is 81%). The long and lateral heads contain three histochemical fiber types: types I, IIa and IIb. Type I muscle fibers account for approximately 18 and 27% of the fibers in the long and lateral heads of the triceps, res...
Preliminary studies on the vascular anatomy of the equine superficial digital flexor tendon. The vascular and microvascular anatomy of normal equine superficial digital flexor tendons was studied by dissection of vinyl-perfused specimens and by microangiography on high detail film. The presence of an extensive intratendinous vascular latticework was confirmed, and a 'nutrient artery' described closely associated with the accessory ligament of the superficial digital flexor tendon (proximal check ligament). Circumferential stripping of the paratenon from the tendon to eliminate afferent vessels was performed bilaterally in three horses and unilaterally in a fourth, followed by a treadm...
In vivo measurement of bone quality in the horse: estimates of precision for ultrasound velocity measurement and single photon absorptiometry. The in vivo precision of ultrasound velocity measurement and single photon absorptiometry for the assessment of equine bone quality is discussed. In vivo precisions for ultrasound velocity measurements were less than 0.5 per cent, whereas cortical cross-sectional area, compact bone density and modulus of elasticity were around 1 per cent, and bone mineral content and density were just over 2 per cent. Except for ultrasound velocity, substantial improvements could be achieved by taking the mean of five readings for each measurement. The long-term precision of the techniques was also high, with ...
Capillary supply and fibre area in locomotor muscles of horse and steer–a comparison between histochemistry and electron microscopy. In order to investigate possible differences in variables defining capillary supply of skeletal muscle derived from two methods, the electron-microscopical and the amylase-PAS histochemical methods were applied in a study of horse and steer muscles. Samples from several locomoter muscles were taken at slaughter from one horse and one steer, divided into two and prepared separately for the two techniques. It was found that there was no difference between the two methods in the values for the capillary-to-fibre ratio. Values for mean fibre area, on the other hand, were significantly higher in th...
Pedicle skin flaps in ponies: viable length is related to flap width. The relationship between pedicle flap width and viable length was characterised for skin flaps of the flank in ponies. Four dorsally based, pedicle type skin flaps of 20 cm in length and 3, 6, 9 or 12 cm in width were created in a random sequence on one flank in each of 10 ponies. Flap survival length was assessed by skin texture and appearance, depilation of hair and wound healing at 14 days after surgery. There was considerable variation between animals in the viable length of flaps of the same width; however, a significant difference in the viable length of flaps of different widths was det...
Sutured end-to-end and stapled side-to-side jejunal anastomoses in the horse. Hand sutured end-to-end (EE) and stapled side-to-side (SS) small intestinal anastomoses were performed in 10 healthy adult horses. In five SS anastomoses, staple lines on the blind ends of the jejunum were inverted (SSI) and in five they were not (SSNI). Five EE anastomoses were sutured with polydioxanone and five were sutured with polyglyconate. All horses were euthanatized on day 30. Intra-abdominal adhesions were graded (0-4), and stomal areas were calculated from contrast radiographs made with the bowel distended. Histopathology scores for the anastomoses were based on the degree of inflam...
Determination of the early age of onset of equine recurrent laryngeal neuropathy. 2. Nerve pathology. The left and right recurrent laryngeal nerves and peroneal nerves from two groups of foals, one less than 1 month of age and the other 6 months of age, were examined by light and electron microscopy. While there was no evidence of fiber loss on light microscopy, occasional onion bulbs, regenerating clusters and swollen axons were seen in the recurrent laryngeal nerves. To quantitate these changes, total counts of the main pathological structures were performed using the electron microscope. In all the foals the most common abnormality seen in the laryngeal nerves were Bungner bands, which were...
Organic structures of the hypercalcified peritubular matrix in horse dentine. EDTA-insoluble organic structures of the hypercalcified peritubular matrix (PM) in horse dentine were observed by scanning electron microscopy. The PM was enveloped in double cylindrical structures composed of fibrillar sheaths in the inner and outer peripheries. Between the outer fibrillar sheath and intrinsic fibrils of the intertubular matrix, a calcified cementing membrane existed. Within the PM, warped cone-shaped structures of fibrillar sheaths, overlapping at intervals of 4-6 microns and semiconcentrically surrounding the dentinal tubule, extended from the inner fibrillar towards the ou...
Bone biopsy in the horse. 2. Evaluation of histomorphometric examination. The histomorphometrical examination of a series of bone biopsies from the wing of ilium of foals and older horses is reported. Biopsies were obtained from 20 clinically normal horses, which had previously been infused with tetracycline intravenously twice at a 7 day interval at a dose rate of 10 to 15 mg kg-1. The horses were divided into 2 groups. Group 1 consisted of 10 foals (mean age: 4 +/- 1 months) which were biopsied at 3 different sites in the wing of ilium. Group 2 comprised 10 older horses (mean age: 91 +/- 63 months) which were biopsied from only one site in the left ilium. A system...
An ultrasonographic off-set system for examination of equine tendons and ligaments. In a dorsal plane, an improved ultrasonographic off-set system was used to obtain serial ultrasonographic images with enhanced anatomic and pathologic detail of the tendons, ligaments, and associated structures of the limbs of 100 horses. The off-set provided good acoustic coupling between a linear array ultrasonographic transducer and the horse's skin. A water-soluble gel contained within the off-set had acoustic properties similar to those of mammalian soft tissues.
Bone biopsy in the horse. 1. Method using the wing of ilium. Two hundred and five bone biopsies from the wing of ilium were taken from 52 growing and 70 older horses. The method was initially evaluated in 4 horses at post mortem and then performed in 26 horses under general anaesthesia. The technique was later developed for biopsying horses in the standing position under local anaesthesia (n = 70 adults; n = 22 foals). The core of the bone biopsy consisted of a central cancellous portion between two cortices. This type of sample allowed a complete histomorphometrical analysis. An integral part of the procedure was intravital bone labelling using fluoroc...
Bone biopsy in the horse. 3. Normal histomorphometric data according to age and sex. Histomorphometrical analysis of bone biopsies from the wing of ilium in 35 clinically normal horses are reported according to age. The biopsies were collected from 20 mixed-bred foals (mean age 6 +/- 1 months) and 15 older horses (mean age 73 +/- 62 months). No gender differences were found in the group of foals examined, but a significant difference (p less than 0.001) in a number of the primary measurements occurred between them and the older horses. The parameters which altered with age were the extent of osteoid surface (OS/BS), the extent of resorption (erosion) surface (ES/BS), the osteo...
Trophoblast-uterine interactions during equine chorionic girdle cell maturation, migration, and transformation. The structure of the equine chorionic girdle between days 28 and 42 of gestation was examined. Of particular interest were differentiation of trophoblastic cells within the girdle, adhesion between girdle and endometrium, invasion and displacement of the uterine epithelium, and the nature of the endometrium when girdle cells migrate into it to form endometrial cup cells. The chorionic girdle, identified initially as a band of tall columnar cells, becomes a stratified columnar epithelium indented by clefts and pits. Adhesion to and penetration through the endometrial luminal epithelium are rapi...
Anomalies of centriolar derivatives manifest in spermatic flagella and respiratory cilia of the stallion. Anomalies of centriolar derivatives were identified in ejaculates and testicular and tracheal biopsies of a sterile stallion, using light, scanning, and transmission electron microscopy. LM revealed that over half the sperm population had only a vestigial or no tail, while the rest had tails of variable length and shape. The vestigial tail was represented by its anlage, which was implanted on the nucleus and differentiated up to capitulum and collum stage. The stunted tail had an axoneme and its derivatives, but was short in all tail segments. Regardless of the tail length or shape, virtually ...
[Adenoma of the pigmented epithelium of the iris with endothelialization and descemetization in the horse]. The authors describe peculiar tumors with brown-white piebald anterior surface, which had grown bilaterally from the corpora nigra (C.N.) of an adult horse and occluded the pupils. The surgical procedure for removing the larger tumor and the postoperative treatment are described. The findings by light and electron microscopy suggest that the tumor represent a so-called adenoma of the iris pigment epithelium. The white patches on its surface consist of newly formed Descemet-like material produced by displaced corneal endothelial cells, which have probably grown on the tumor after contact with t...
Equine synovial tendon sheaths and bursae: a transmission electron microscope study. A transmission electron microscope study was undertaken to investigate the details of the synovial tendon sheath and bursal lining in horses. The lining cells appeared to be fibroblasts and were buried in a finely granular ground substance. Generally these cells had poor cytoplasmic organelles, sparse short profiles of rough endoplasmic reticulum (RER), few scattered ribosomes and, occasionally, a poorly developed Golgi complex. However, a few lining cells appeared more active, having pronounced RER with dilated cisternane. The surface of the lining cells, particularly those with dilated RER, ...
Measurement of cardiac dimensions with two-dimensional echocardiography in the living horse. Two-dimensional echocardiography (2DE) was performed on 22 unsedated Thoroughbred and part Thoroughbred horses weighing between 411 and 650 kg to establish normal reference values for 2DE measurements. Animals stood during examinations performed with a 3.5 MHz mechanical sector transducer using various transducer positions and tomographic planes. Right ventricular diameter (RVD), ventricular septal thickness (VSTh), aortic diameter (AoD), area of the chordal lumen of the left ventricle (CTA), left ventricular diameter (LVD) and left atrial diameter (LAD) were determined at ventricular end-dias...
Evaluation of epiglottic augmentation by use of polytetrafluoroethylene paste in horses. Epiglottic augmentation was evaluated in 7 horses, using 7 ml of polytetrafluoroethylene (polytef) paste injected submucosally on the ventral surface of the epiglottis. In 6 horses, an Arnold-Bruning intracordal injection syringe, specifically designed to inject polytef into paralyzed vocal folds in human beings, was used. At necropsy 60 days after surgery, group mean thickness measurement 20 mm from the epiglottic tip was 40% greater (P less than 0.01) and, at the epiglottic attachment of the aryepiglottic fold, was 29% greater (P less than 0.01) in the 6 polytef-augmented horses than in clin...
