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.
Riley CB, Yovich JV.Fractures of the patella in the horse are infrequently reported
in the literature. Most of these have been associated with trauma
or sudden forceful contraction of the quadriceps resulting in an
avulsion fracture of the patella (Parks and Wyn-Jones 1988).
There have been few reports of fractures associated with des-
motomy of the medial patellar ligament to correct upward
fixation of the patella (Wright and Rose 1989; Gibson ef ul1989).
This paper describes one such case including the radiographic
findings before the desmotomy, after fracture of the patella and
after arthroscopic trea...
Martin BB, Nunamaker DM, Evans LH, Orsini JA, Palmer SE.Circumferential wiring was used to repair 12 mid-body fractures and four large basilar fractures of proximal sesamoid bones in 15 horses. Eighteen-gauge stainless steel wire was placed around both fragments in five horses, and through the proximal fragment and around the distal fragment in 10 horses. The horses were returned to work when they were clinically sound and fracture healing was evident radiographically. Eleven horses resumed athletic performance, three horses were used as breeding animals, and one horse was retired. Five horses performed at an athletic level equal to or better than ...
Rakestraw PC, Nixon AJ, Kaderly RE, Ducharme NG.A cranial approach to the humerus was developed for application of a compression plate for repair of comminuted humeral fractures in a weanling foal, a calf, a heifer, and a mature cow. An incision was made from the cranial portion of the greater tubercle of the humerus to the radius. The cranial aspect of the humerus was exposed by retraction of the brachiocephalicus muscle and blunt dissection between the biceps brachii and brachialis muscles. A second plate was applied laterally in the heifer and cow by retraction of the brachialis muscle and elevation of the extensor carpi radialis muscle....
Nunamaker DM, Butterweck DM, Black J.In vitro local fatigue testing of the third metacarpal bone from Thoroughbred and Standardbred racehorses was performed, using fully reversed cyclic bending. Strain number of cycle data were accumulated and indicated that significant difference did not exist between the 2 breeds. It was concluded that the marked difference in the incidence of fatigue failure in the third metacarpal bone (bucked shins, dorsal metacarpal disease) seen in Thoroughbreds and Standardbreds was not related to any differences between the 2 breeds in mechanical properties of the bone.
Nunamaker DM, Richardson DW, Butterweck DM.Plate luting, a technique that uses polymethylmethacrylate (PMMA) interposed between the plate and the bone, as well as between the screw heads and the plate, to improve the stability of internal fixation was tested in vitro using 20 paired equine third metacarpal bones with mid-diaphyseal osteotomies plated with six-hole broad ASIF compression plates. One of each pair was luted and all specimens were tested in static overload or cyclic loading at 75% of the ultimate breaking strength using four-point bending. Although no differences were measured in static overload tests between luted and non...
Trout DR, Hornof WJ, O'Brien TR.Radiography and soft tissue- and bone-phase scintigraphy were performed on 14 clinically normal horses and 35 horses in which definite, probable, or possible navicular disease had been diagnosed. The specificity of radiography and scintigraphy in revealing signs of navicular disease were nearly equal; however, the sensitivity of scintigraphy appeared to be greater than that of radiography. The greatest sensitivity and specificity were achieved when the results of radiography and scintigraphy were evaluated together. Differences in sensitivity were greatest when scintigraphy revealed lesions no...
Barneveld A.The pathogenesis of bone spavin and its implications for diagnosis and therapy are reviewed. The pathogenesis of spavin can be divided into three phases, which are characterised by fibrillation of cartilage, osteolysis and ankylosis respectively. It will depend on the degree of osteolysis whether diagnostic anaesthesia should be added to standard clinical and radiological examinations. Satisfactory results of treatment in the group of patients with severe osteolysis can only be obtained by arthrodesis of the distal tarsal joints. It is expected that biomechanical investigations will provide a ...
Firth EC.In chondro-osseous disease in the foal there are three main categories of lesions: (i) synovitis alone (type S), (ii) synovitis accompanied by osteomyelitis originating in the epiphysis of the juxta-articular bone (type E) and (iii) synovitis accompanied by osteomyelitis originating directly adjacent to the physis of the juxta-articular bone (type P). Observations made in studies of the immature radius and metacarpus provide an explanation for the apparent predisposition of some joints for this disease. Relevant clinical and therapeutical aspects are discussed.
Németh F.The aetiology and pathogenesis of navicular bone disease and sesamoidosis are discussed on the basis of findings reported in the literature and research. A marked similarity is found to be present between the clinical presentation, aetiology and pathogenesis of these two diseases. In addition, the intra and juxta-articular signs of degeneration as seen in these diseases are similar to those seen in various forms of arthrosis. Circulatory disturbances resulting from partial or complete arterial occlusion, caused by arteriosclerosis, are likely to play an important role in the cause of degenerat...
Orsini JA, Buonanno AM, Richardson DW, Nunamaker DN.A Salter-Harris type-II fracture of the distal portion of the femur in a 1-year-old Pony of America was repaired by use of lateral plating combined with interfragmentary compression. The configuration of the fracture and the method of internal fixation with a condylar buttress plate were unique and resulted in primary bone healing, seen at the 5-month follow-up examination.
Stolk PW, Firth EC.Intra-osseous pressure measurements in the third metatarsal bone of anesthetised young and mature ponies demonstrated that a pressure gradient exists along the bone, the pressure being highest at the level of the nutrient foramen and decreasing distally and proximally from this point. The height of the intra-osseous pressure pulse also decreased toward the bone ends. It is concluded that the sites of measurement of the intra-osseous pressure in clinical and experimental studies should be standardized.
Specht TE, Poulos PW, Metcalf MR, Robertson ID.Vacuum phenomenon was induced inadvertently during radiographic examination of a metatarsophalangeal joint of a lame horse. The phenomenon was recreated in a sound horse when a metacarpophalangeal joint was radiographed in a stress-flexed position. Distraction of apposing articular surfaces may induce the vacuum phenomenon, which could result in misdiagnosis of an osteochondral defect or fracture.
Kneller SK, Losonsky JM.Bilateral metacarpophalangeal radiographs of 100 Thoroughbreds were examined for visualization and location of the major nutrient foramen of the proximal phalanx. The foramina were located on the dorsal or palmar aspects of the cortex or were not visible radiographically. Of the 100 horses, 60 had the same pattern in both forefeet. In the remaining 40 horses, the left and right proximal phalangeal foramina were asymmetric. Of the 200 proximal phalangeal foramina (100 horses), 53 were on the dorsal aspect of the cortex and 101 were on the palmar aspect of the cortex; 46 were not visible radiogr...
Specht TE, Miller GJ, Colahan PT.The breaking strength (stress at failure) of equine third metacarpal bones, with and without clustered drill holes, was determined in vitro. Paired ossa metacarpalia II-IV of 39 horses (n = 39) between 2 and 7 years old were tested in palmarodorsal 3-point bending. Four treatments were compared. Clustered 2.7- or 3.5-mm drill holes, in a 4- or 7-hole pattern, were made in the dorsal cortex of the distal diaphysis of the left third metacarpal bone. Undrilled right third metacarpi were used as controls. Bones with clustered drill holes failed by an oblique fracture through 1 or more drill holes,...
Langton CM, Ali AV, Riggs CM, Evans GP, Bonfield W.A portable system using a direct contact for the measurement of ultrasonic velocity and broadband attenuation in bone is described (contact ultrasonic bone analyser, CUBA). Soft-tissue compensation is performed using an ultrasonic pulse-echo technique. CUBA has been successfully validated using reference materials, the precision of velocity and broadband attenuation measurements being typically 0.2% and 0.5% respectively. The clinical reproducibility has been assessed on the equine third metacarpal bone. The reproducibility of velocity measurement is typically 0.5% for cortical bone and 1% for...
Nunamaker DM, Butterweck DM, Provost MT.The North American Thoroughbred racehorse was chosen as a model to study the pathogenesis of fatigue failure of bone. This species has a high incidence of spontaneous fatigue failure of bone (bucked shins) during its early training. In vivo strain gauge studies of the third metacarpal bone of four young racehorses running at racing speeds showed high principal compressive strains [-4,841 +/- 572 (SD) microstrain] while two older horses had lower principal compressive strains (-3,317 microstrain measured at racing speed, -3,250 microstrain extrapolated from a slower speed run). Previously repor...
Nyrop KA, DeBowes RM, Ferguson HR, Leipold HW, Wilson JW, Guffy MM.The arterial blood supply to the diaphysis of the radius, and the vascular reaction when three cerclage devices (cerclage wire, Parham-Martin band, and a partially contacting band) were applied 2 cm apart, were studied in six adult ponies. The opposite radial diaphysis served as the control. Ponies were euthanatized at weeks 4 and 8. A centrifugal blood flow pattern was demonstrated by microangiography. Larger numbers of medullary arteries exist in equine than in canine and human long bones. Changes in centrifugal blood supply were not identified beneath any of the cerclage devices.
van Weeren PR, van den Bogert AJ, Barneveld A.Displacement of skin over the underlying skeletal structures in the proximal parts of the limbs was investigated in four walking Dutch Warmblood horses. Movement of the skin was visualised with self adhesive spot labels whereas that of the skeletal parts was visualised indirectly by means of a plastic strip connected to a transcutaneous Steinmann pin, driven into the bone of interest. Consistent results for all four horses were found. Individual and mean total displacements ranged from 1 to 4 cm (distal scapula) to 13 to 17 cm (caudal part of the greater trochanter of the femur). Displacements...
Lanyon LE.The skeleton consists of a series of elements with a variety of functions. In locations such as the skull, where shape or protection are of prime importance, the bone's architecture is achieved during growth under predominant genetic control. In locations such as the limbs, where the ability to withstand repetitive loading is important, only the general form of the bone will be achieved as a result of growth alone, the remaining characteristics resulting from an adaptive response to functional load bearing. In the horse, this functional load-bearing will be provided by the animal's natural act...
Wilson DG, Trent AM, Crawford WH.A surgical approach to the ramus of the mandible was developed. Subperiosteal elevation of the masseter muscle from the ramus allowed reduction and plate fixation of ramus fractures in a bull and a horse. Results of follow-up examinations, 2 years after surgery, showed excellent functional and cosmetic results.
Barber SM.A 2 month old quarter horse colt had multiple skeletal abnormalities of the left fore limb, including two supernumerary metacarpal bones, two supernumerary carpal bones, abnormal carpal bone development, and a valgus deformity originating at the carpal joint. The largest supernumerary metacarpal bone was removed completely, a portion of the smaller supernumerary metacarpal bone was removed, and the leg was placed in a tube cast. Surgical treatment improved the clinical appearance and prevented further injury to the limb. The carpal joint width remained increased but the carpal valgus deformity...
Caron JP, Fretz PB, Bailey JV, Barber SM.Arthrodesis of the proximal interphalangeal joint was used to treat lameness resulting from osteoarthrosis and for closed subluxation in 35 horses. Six horses had bilateral arthrodeses. Several conventional internal fixation techniques and a three converging screw method were used. Criteria for success included the horse performing its previous or intended athletic activity and the owner being satisfied with the outcome. Using these criteria, a successful outcome was obtained in 65% of the 26 animals in which adequate follow-up was available. A successful outcome was observed in four of six ho...
Barr AR, Sinnott MJ, Denny HR.The clinical signs and radiographic appearance of 19 cases of fracture of the accessory carpal bone of horses are described. In 17 cases the fractures were in the frontal plane and occurred palmar to the groove on the lateral aspect of the bone. In six cases radiographs taken six months to three years after the fracture occurred showed no evidence of bony union; nevertheless, these and five other horses for which follow-up information was available for up to seven years all became sound, and seven of them returned to competitive activity.
Updike SJ.Tendons of insertion of the equine tibialis cranialis muscle and peroneus tertius muscle (PT) were dissected grossly. Precise areas of tendon attachment and fiber arrangements within the tendons were described for the dorsal and medial tendons of the tibialis cranialis, and for the superficial lateral, deep lateral, dorsal, and medial tendons of the PT. Direct attachment of the dorsal and medial tendons of the PT into the periosteum of the central and 3rd tarsal bones and the 3rd metatarsal bone indicates that the PT may be involved in the pathogenesis of hock lamenesses.
Sherlock CE, Mair TS, Murray RC, Blunden TS.Emaciated human patients have changes in the fat content in medullary bone that are consistent with serous atrophy of the bone marrow histologically. Serous atrophy has been identified at postmortem examination in horses; however, the magnetic resonance (MR) characteristics have not been documented. Herein we describe the abnormalities of the bone marrow and medullary bone detected by low-field and high-field MR imaging of the distal limbs of three emaciated horses. These low- and high-field MR imaging abnormalities are characterized by a decrease in signal intensity on T1-weighted images in c...
Jann H, Henry G, Berry A, Cash L.Twenty cadaver limbs of adult horses were examined by arthrographic examination of the distal interphalangeal joint. The joint capsule and space is described. Comparison is made with existing descriptions.
Adrian M, Grant B, Ratzlaff M, Ray J, Boulton C.Electrogoniometry was used qualitively and quantitatively to assess the movements of the normal and pathologic metacarpophalangeal joints of selected horses. A total of 4 Thoroughbreds, 1 normal and 3 with clinical and radiographic changes in the metacarpophalangeal joints of 1 limb, were evaluated at the walk and trot. Goniograms of the affected joints were compared with those of the normal horse and the normal contralateral metacarpophangeal joint. Qualitative asymmetry was recognized on the goniograms, and the ranges of motion were quantified and related to the clinical and radiologic obser...
McKibbin LS, Paraschak DM.Bone spavin, splint, and fractured splint bone injuries have been treated with varying methodologies at Wheatley Hall Farm Equine Clinic. Cryosurgery is the most successful. With cryosurgery the small, pain-producing afferent C fibers are destroyed, and painful neuromas do not return. Injured sites were cryosurgically treated with liquid nitrogen for a double freeze-thaw period of 45 sec. 5 sec, 45 sec. Before and after treatment comparisons were conducted on study standardbreds. In all three injury groups, results showed that the standardbreds tended to race as well or with improved times and...