The skeletal system in horses comprises a complex structure of bones that provide support, protection, and mobility. Equine bones are involved in various physiological functions, including mineral storage and hematopoiesis. The bone structure in horses is categorized into different types, such as long bones, short bones, flat bones, and irregular bones, each serving specific roles in movement and stability. Research in this area explores topics such as bone development, remodeling, and the impact of nutrition and exercise on bone health. This page gathers peer-reviewed studies and academic articles that focus on the anatomy, physiology, and pathology of bones in horses, offering insights into conditions such as fractures, bone diseases, and the effects of aging on the equine skeletal system.
Blevins WE, Widmer WR.This article focuses on the principles involved in making radiographs of equine limbs; understanding radiographic anatomy, including normal variations; and principles of radiographic interpretation. The influence of pathogenesis of disease on the radiographic image is considered. Diseases associated with racing as well as the developing racehorse are discussed.
Lepage OM, Marcoux M, Tremblay A.Levels of alkaline phosphatase and osteocalcin or bone Gla-protein, a new marker of bone metabolism, were analyzed in blood samples of 50 clinically normal female Standardbred horses between four months and twenty years of age. Samples were collected in the morning before exercise. Serum osteocalcin was measured by radioimmunoassay using bovine antibodies. There was a significant inverse correlation between alkaline phosphatase, osteocalcin and the age of the animals up to 48 months. The decrease in osteocalcin levels in serum was very marked during the first 30 months of life. The mean osteoc...
Kannegieter NJ, Burbidge HM.The radiographic and arthroscopic findings in 150 carpal joints in 114 lame horses were compared. Chip, slab, or sagittal fractures were identified in 130 (87%) joints. In 101 (78%) of these there was good agreement between radiographic and arthroscopic findings on the number and position of fractures. In 23 (18%) joints, chip fractures additional to those seen radiographically were found arthroscopically. In one joint a large chip fracture from the craniolateral aspect of the distal radius was identified only by arthroscopy, while in 6 joints fractures were identified only by radiography. Obs...
Nixon AJ, Spencer CP.Techniques and normal radiographic anatomy for positive and double contrast shoulder arthrography in horses were evaluated. General anaesthesia was used for most radiographic projections of the shoulder. The mediolateral projection provided the most information during arthrography, although the supinated mediolateral view occasionally allowed better definition of the cartilage surfaces on the medial aspects of the humeral head. The craniocaudal mediolateral oblique and caudocranial projections provided limited additional information. Water soluble non-ionic contrast agents, such as metrizamide...
Gaughan EM, Wallace RJ, Kallfelz FA.The effects of two local anesthetic agents on the diagnostic quality of nuclear medical bone images (NMBIs) of distal parts of the equine fore limb were investigated. Local effects on bone uptake of technetium 99m methylene diphosphonate (99mTc-MDP) 4 and 24 hours after perineural and intraarticular injection of mepivacaine hydrochloride and bupivacaine hydrochloride were evaluated in the carpal and metacarpophalangeal regions of 12 horses and ponies. Neither mepivacaine hydrochloride nor bupivacaine hydrochloride significantly altered the diagnostic quality of the NMBIs. The injection and sub...
Hunt DA, Snyder JR, Morgan JP, Stover SM, Pool RR, Pascoe JR.Femoral neck and proximal epiphyseal lengths were measured in 37 femurs from 19 cadaver foals that were 1 day to 12 months old to determine the applicability of a human interfragmentary compression system to equine femoral capital physeal fractures. Because components of the implant system are available only in fixed sizes, its use was possible in foals older than 5 weeks of age, but not in younger foals. The 135 degree angle plate conformed best to the equine femur. Femoral capital physeal fractures were created surgically and repaired with the implant system in three foals. Fracture stabilit...
Nixon AJ.Periarticular anatomy and techniques for arthroscopic access to the equine elbow were studied in six joints from cadavers. Caudomedial and craniolateral approaches were evaluated subsequently in 11 anesthetized horses. The caudomedial approach was made between the flexor carpi radialis and flexor carpi ulnaris muscle bellies. Most of the caudal articular surfaces of the humeral condyles, the caudal perimeter of the radius, and the trochlear notch and portions of the anconeal process of the ulna could be identified. The voluminous caudal joint capsule cul-de-sac proximal to the anconeal process...
Freeman DE, Orsini PG, Ross MW, Madison JB.A large frontonasal bone flap was created to treat diseases of the paranasal sinuses in 14 horses. The bone flap was made as wide as possible within the confines of the nasolacrimal duct so the floor of the frontal sinus and the dorsal and ventral conchae could be opened. These openings exposed the nasal passages, maxillary sinuses, and ventral conchal sinus thereby facilitating removal of diffuse and localized lesions from these sites. Diseases treated were ethmoid hematomas (4 horses), sinus cysts (5 horses), cryptococcal granuloma, osteoma, hemangiosarcoma, pus in the ventral conchal sinus,...
Beard WL, Robertson JT, Leeth B.Congenital frontal sinus cysts were found bilaterally in the frontal sinuses of a one-year-old miniature horse. Diagnosis was based on radiography of the head and cytologic examination of tissue aspirated from the frontal sinuses. The cysts were surgically removed, using a hinged bone flap technique bilaterally over the frontal sinuses.
van den Bogert AJ, van Weeren PR, Schamhardt HC.In movement analysis of the horse, large errors result from movements of the skin with respect to the underlying bones. A generally applicable, two-dimensional, method for correction of these skin-movement errors in kinematic data has been developed. It was tested on a kinematic analysis of the hindlimb in a walking pony. The results indicate that without correction for skin-movement errors, misreadings of up to 15 degrees in the knee angle and 30% in the moment arm of the gastrocnemius muscle can be expected.
McCarthy RN, Jeffcott LB, McCartney RN.Ultrasound speed, as measured by a transmission technique in equine cortical bone, was found to vary markedly with the direction of the ultrasound path through the bone. Using bone samples from the mid-site of the third metacarpus of 20 horses, the ultrasound speed was measured as 4125 m s-1 in the longitudinal direction, 3442 m s-1 in the circumferential or transverse direction, and 3428 m s-1 in the radial direction. These results confirm the anisotropic properties of compact bone. Ultrasound speed had a positive linear relationship when compared with bone specific gravity of cortical bone (...
Albu I, Georgia R, Georoceanu M.The Haversian canal system in the diaphysial compacta of the femur in 4 mammalian species (dog, pig, bovine, horse) was studied on the decalcified bone using a method developed by the authors. In the microscopic studies we found that in all species the network aspects vary with the depth of the compacta layer. In all layers, there is a background of longitudinal canals with more or less regular trajectories describing large curves. The anastomoses linking them are main elements that define the variety of the network aspects both from layer to layer and from species to species. The canal densit...
Shamis LD, Sanders-Shamis M, Bramlage LR.A 3-week-old Standardbred filly had a non-weightbearing forelimb lameness caused by scapular neck fracture. The fracture was repaired with 2 dynamic compression plates placed 90 degrees to each other. A 10-hole 4.5-mm narrow dynamic compression plate was placed on the cranial aspect of the scapular spine, and a 10-hole 3.5-mm dynamic compression plate was placed caudal to the scapular spine. One year after surgery, the filly was not lame when exercising in the pasture, and muscle atrophy was not evident on the affected limb. Eighteen months after surgery, the filly was in race training with no...
Ostblom L, Lund C, Melsen F.Twelve horses suffering from navicular bone disease were examined in a prospective, controlled histomorphometric study for six months. The objective was to compare the histology of navicular bones from untreated animals to those treated with the egg-bar shoeing technique. These data were compared to similar sections from three normal animals. The current investigation provided quantitative support to previous findings concerning clinical improvement. Detailed histology, changes in bone morphometry and pathophysiological reactions are discussed.
Gibson KT, McIlwraith CW, Park RD, Norrdin RW.Medial patellar desmotomy was performed on one (treated) hindlimb, and a sham operation on the other (control) hindlimb, of 12 normal horses. The horses were examined for lameness before medial patellar desmotomy and at months 1, 2, and 3. The femoropatellar joints were examined radiographically and arthroscopically at month 3. All horses were lame on the treated limb at months 1, 2, or 3. Radiographic changes, including fragment formation at the distal aspect of the patella and bone production at the attachment of the middle patellar ligament on the patella, were present in 11 horses at month...
Rijkenhuizen AB, Németh F, Dik KJ, Goedegebuure SA.A macroscopic, arteriographic and histological study of the development and the arterial anatomy of the navicular bone of 33 foetuses and 55 young horses is described. After 125 days of gestation the blood supply consists of two routes: one situated in the superficial layer of the fibrocartilage and the other similar to the blood supply of the navicular bone of the normal mature horse. After 270 days gestation, the blood vessels in the fibrocartilage gradually regressed and retracted until they have disappeared at six months after birth. At two months after birth the first macroscopic thinning...
Rijkenhuizen AB, Németh F, Dik KJ, Goedegebuure SA.A macroscopical, arteriographical and histological study was made of the arterial supply of the navicular bones of horses with clinical and/or radiographic signs of navicular disease. Based on the clinical and radiological findings the navicular bones of 40 Warmblood horses are divided into four different groups. In the pattern of the arteriogram obvious changes are noticed: an imbalance and a distal to proximal shift between the distal and proximal arterial supply occur, indicating a reduction of the distal blood supply with a compensatory reaction of the proximal, medial and lateral supply. ...
Rijkenhuizen AB, Nemeth F, Dik KJ, Goedegebuure SA.An arteriographic and histological study of the arterial blood supply of 35 navicular bones, from 19 adult horses with no clinical or radiographical signs of navicular disease, is described. The arteries enter the navicular bone from four directions: distal, proximal, medial, and lateral. The navicular bone can be divided into areas which receive arteries from one, two, or three directions, whereas the distal supply covers the largest part of the navicular bone. The distal arteries enter the navicular bone through the nutrient foramen which contains loose connective tissue, nutrient vessels an...
Raub RH, Jackson SG, Baker JP.Nineteen weanling horses (average age = 147 d) were divided into exercised (EX; n = 10) and nonexercised (NEX; n = 9) groups, with age, sex and breed represented as equally as possible. The EX group was exercised on an automatic walker at a medium trot for up to 20 min, 5 d each week. Both groups were fed to meet 100% of their protein and 110% of their energy requirements (NRC, 1978). The EX group's diet was supplemented, on exercise days, with corn starch to meet the additional energy requirements for exercise. The experiment was conducted over a 111-d period. Body weight was measured at 10-d...
Bukowiecki CF, van Ee RT, Schneiter HL.A comminuted scapular fracture in a foal was treated surgically by use of 2 dynamic compression plates. The plates were applied upside down, so that the convex surface of the plate faced the bone. At 5 months after surgery, the plates were removed, and the foal recovered without complications.
Kirberger RM, Gottschalk RD.The clinical, radiological and anatomical changes in a yearling foal with kyphoscoliosis are described. The lesion was due to a primary malformation of the eleventh, twelfth, fourteenth and fifteenth thoracic vertebral bodies resulting in hemivertebrae. Secondary changes occurred in the laminae, pedicles, spinous and articular processes of the affected vertebrae and the adjacent vertebrae. The possible pathogenesis and differential diagnosis are discussed.
Prades M, Grant BD, Turner TA, Nixon AJ, Brown MP.The clinical, radiographic, arthroscopic and pathological findings of 10 horses with injury to the cranial cruciate ligament are presented. The most consistent clinical signs included moderate to severe distension of the femoropatellar joint and a Grade III to a Grade V out of V lameness. Craniocaudal instability could be elicited in five horses under general anaesthesia and in one conscious horse. Radiographic evaluation of the stifles revealed that avulsion fracture of the medial intercondylar eminence was the most common finding in six out of 10 horses. Arthroscopic examination of the affec...
Marqués FJ, Sharma A, Wilson DG.Advanced diagnostic imaging and histopathological investigation were performed in an adult horse with chronic facial swelling due to a bone sequestrum and abscessation. In contrast to other cases, there were no draining tracts, difficulty eating, weight loss, head shaking, or fistula formation between the oral cavity and the maxillary sinus. Une investigation d’imagerie diagnostique avancée et un examen histopathologique ont été réalisés chez un cheval adulte présentant de l’enflure faciale chronique attribuable à un séquestre osseux et à une abcédation. Par contraste à d’aut...
Summers PM, Wells KE, Adkins KF.The features of an ossifying ameloblastoma in a 5-year-old gelding are described. The tumour developed in the angle of the right mandible and microscopically consisted of multiple follicles and islands of epithelial tissue adjacent to which were trabeculae of bone, osteoid and compact collagenous tissue.
Schumacher J, Kemper DL, Helman RG, Edwards JL.The incisive bones (premaxillae) and rostral portions of the maxillae of a horse were infected with dermatiaceous fungi causing phaeohyphomycosis. The pre-maxillae were exposed by creating and reflecting labial and palatal mucoperiosteal flaps, and obstetrical wire was used to remove the affected bones. Labial and palatal flaps were apposed in 2 layers, using absorbable sutures. The sutured wound healed without complication. The horse was able to prehend hay and long grass without difficulty, and the owner considered the horse's facial appearance to be nearly normal. This technique may be usef...
Meehan LJ, Taylor SE, Labens R, Cillán-García E.Assessment of the usefulness of magnetic resonance imaging (MRI) in treatment planning in suspected cases of quittor in the horse. Methods: Five horses with chronic discharging tracts at the level of the foot underwent MRI for treatment planning. Results: The MRI examination revealed variable involvement of soft tissue and osseous structures of the foot in addition to abnormalities of the ungular cartilages in all cases. In two cases, follow-up MRI examination was performed. Four of five horses had a successful outcome, with three of these undergoing only one surgical procedure and one being m...
Dik KJ, Nemeth F.Six cases of patella fractures are reported. Three horses presented an avulsion fracture of the medial patellar angle. For a precise diagnosis of this fracture a radiographic skyline view was indispensable; lateral views were not diagnostic. One of these horses recovered after three months' rest but radiographically the fracture remained visible. One horse with a comminuted fracture recovered after five months' rest. A case with a contaminated longitudinal patella fracture was destroyed. The sixth horse had a chip fracture of the dorsomedial part of the patella. The outcome of this case is unk...
Amaniti EM, Diakakis N, Patsikas M, Savvas I.Epiphyseal fracture, also known as epiphysiolysis, is the loosening or separation, either partial or complete, of an epiphysis from the shaft of a long bone. Distal epiphyseal fractures in foals pose a substantial challenge due to their guarded prognosis. This report describes the clinical signs, diagnosis, successful conservative treatment of an 1-month-old, male Skyros pony with an epiphyseal fracture of the right third metacarpal bone (type II Salter-Harris). The owner declined surgical treatment because of financial considerations along with the unfavorable prognosis. Conservative fracture...