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.
Savage CJ, Tidd LC, Melsen F, Jeffcott LB, Ostblom L.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...
Savage CJ, Tidd LC, Ostblom LC, Melsen F, Jeffcott LB.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...
Canè V, Botti P, Farneti D, Soana S.The effect of pulsing electromagnetic fields (PEMFs) on bone repair was studied in principal metacarpal bones of eight adult male horses: Six horses were treated with PEMFs, and two horses were untreated. In treated horses, Helmholtz coils were applied during a 60-day period to the left metacarpal bones, bored with eight holes of equal diameter and depth, from the middiaphysis toward the distal metaphysis. Eight equal holes bored in the right metacarpal, surrounded by unactivated Helmholtz coils, were taken as controls. The two untreated horses were taken as additional control. The results of ...
Laverty S, Stover SM, Bélanger D, O'Brien TR, Pool RR, Pascoe JR, Taylor K, Harrington T.Clinical radiographic (LM and D35L-P1MO views), high detail radiographic, microangiographic and histological findings of the distal portion of the tarsus of 16 horses (five weanling, four young and six adult), without known clinical histories, were evaluated to determine the sensitivity of clinical radiographs for the detection of abnormalities in the distal tarsus and the prevalence of abnormalities in this population. Clinical radiographic and high detail radiographic abnormalities were observed in at least 30 per cent of the tarsi examined. Statistical agreement between observations from cl...
Burba DJ, Collier MA.A 5-hole T-plate was used to repair an unstable compound depression fracture of the nasal bones in a horse. Substantial bone loss was evident as a result of severe trauma. Satisfactory bone healing, facial contour, and airway function were achieved. The use of a T-plate can be an alternative means of repair of a nasal bone fracture in a situation in which instability and/or bone loss exists.
Körber HD.Radiographic examination is a valuable means for the identification of ossified lateral cartilage. The extent and stages of development of the ossification can be determined. The active stage of development of ossified lateral cartilage, which by itself can provoke lameness, can be defined. By means of the X-ray it is tried to differentiate the three kinds of ossification: the enchondral, the peri- and parachondral ossification of the lateral cartilage. Centres of ossification and fractures of the ossified lateral cartilage are described.
Wisner ER, O'Brien TR, Pool RR, Pascoe JR, Koblick PD, Hornoff WJ, Poulos PW.Destructive lesions of the axial region of the proximal sesamoid bones were identified by radiography in eight fetlocks and seven lame adult horses. Lameness ranged from 2 to 5 (mean 4; scale 1 to 5) at the time of examination, with a duration of 10 days to two years (mean 5.6 months). Destructive lesions involved both proximal sesamoid bones when examined radiographically and were situated primarily at the level of the mid-body and apical region of the axial borders. Some lesions were cystic, whereas others eroded the axial border more diffusely. Scintigraphy revealed markedly increased activ...
Henninger RW, Bramlage LR, Schneider RK, Gabel AA.Case records of 25 horses with transverse fractures of the proximal sesamoid bone were reviewed to evaluate the success of treatment. All fractures were repaired by use of lag screw fixation and an autogenous cancellous bone graft because the fracture fragments were considered too large for surgical removal and reconstruction of the suspensory apparatus was necessary. Radiography was performed in all cases, and the fractures were classified into 3 types: (1) proximal midbody fractures, which included all fractures in the proximal aspect of the sesamoid bone that resulted in fragments involving...
Smith BL, Auer JA, Taylor TS, Hulse DS, Longnecker MT.Cortical bone screws were implanted into the proximal portion of the right and left radius and ulna of 6 newborn Quarter Horse foals as radiographic markers for measurement of growth. Distance between markers on a lateral radiographic view was measured. Radiographs were taken at 2-week intervals until the horses were 8 weeks old, at 4-week intervals until they were 48 weeks old, and at 12-week intervals until they were 72 weeks old. The proximal radius and ulna grew at similar rates during the 72-week period of evaluation, and growth continued throughout 72 weeks. The proximal radius grew 3.5 ...
Harrison LJ, May SA, Richardson JD, Mills G, Dixon P.Four horses with an incomplete fracture of a hindlimb longbone were examined. In two, the tibia had been fractured by external trauma. In the other two horses proximal metatarsal 3 had fractured during normal activity. The diagnoses were made radiographically and the horses were treated conservatively by box rest. The fractures healed satisfactorily and the horses became sound.
Meyer PK.The article reviews German anatomical terms applied to longer limb bones and their joints of the horse. The listed terms have been used in German veterinary and special veterinary anatomical hand- and textbooks since 1774; etymological remarks are made on some unusual words.
Baxter GM, Moore JN, Budsberg SC.An open radial fracture in an adult horse (450 kg) was repaired by internal fixation, using two 18-hole 4.5-mm broad dynamic compression plates and 5.5- and 4.5-mm bone screws. The fracture healed completely, but when evaluated 9 months after surgery, the horse was lame on the fractured limb at a trot. Local infiltration of anesthesia along the distal half of the bone plates greatly ameliorated the lameness, suggesting that the plates were irritating the soft tissues and extensor tendons along the cranial and lateral aspects of the antebrachium. Both bone plates were removed simultaneously wit...
Steckel RR.Bone scanning to help diagnose orthopedic disease has been used in human patients for over two decades. The value of this diagnostic tool has been well established in helping to identify a variety of musculoskeletal conditions. It has only recently been used by veterinarians for more accurate characterization of equine musculoskeletal disease. The technique offers the major advantage of increased sensitivity over standard radiographic imaging. The case material illustrated here shows that except for consistent identification of bone cysts, most of the pathologic changes to the horse's musculos...
Young DR, Nunamaker DM, Markel MD.Eight untrained 2-year-old Thoroughbred horses were used in a study of the remodeling response of the proximal sesamoid bone (PSB) to training-related stimuli. Two horses each were assigned to 1 of 4 groups: group 1, untrained, pasture turnout (control); group 2, modified-classically trained, dirt track; group 3, classically trained, dirt track; and group 4, classically trained, wood chip track. Horses were given fluorochromic bone labels every 28 days during training. All horses were euthanatized after 5 months of training, and the proximal sesamoid bones (PSB) were removed. A midsagittal sec...
Gaughan EM, Gift LJ, DeBowes RM, Frank RK, Veatch JK.An 8-year-old Quarter Horse mare was examined for chronic nasal discharge and obstruction of both nasal passages. A solid mass lesion was identified in the maxillary sinuses, soft palate, nasal and pharyngeal cavities. Palliative surgery was used to debulk the lesion and facilitate nasal airflow. Squamous cell carcinoma was diagnosed from surgical biopsies. Approximately 7-8 weeks after surgery, the mare was observed to be acutely blind. Ophthalmologic examination revealed central origin blindness and active retinitis. The squamous cell carcinoma had reobstructed the nasal passages. Pressure b...
Harrison LJ, May SA, Edwards GB.Over a period of 16 years, 26 horses were treated for open fractures involving the splint bones. Treatment consisted of surgical excision of fracture fragments and sequestra, and curettage of infected and unhealthy tissues. The splint bone distal to the fracture was removed in nine horses in which the attachment of the splint bone to the cannon bone via the interosseous ligament did not provide adequate stability. In two horses it was considered necessary to stabilise the proximal fragment by internal fixation and infection developed in both of them; one of these horses was destroyed on humane...
Weber A, Ligthelm AJ, Verstraete FJ.An 8-year-old Hannoverian horse developed a swelling of the maxilla caused by a tumour of the hard palate. On histological examination the tumour was diagnosed as a primary intra-osseous carcinoma of the maxilla, a rare odontogenic tumour not previously described in the horse.
Nixon AJ, Krook LP, Roth JE, King JM.A pulsed carbon dioxide laser was used to vaporize articular cartilage in four horses, and perforate the cartilage and subchondral bone in four horses. Both intercarpal joints were examined arthroscopically and either a 1 cm cartilage crater or a series of holes was created in the third carpal bone of one joint. The contralateral carpus served as a control. After euthanasia at week 8, the treated and control joints were examined for gross changes, and samples of cartilage and subchondral bone, synovial membrane, and peripheral lymph nodes were examined histologically. Depletion of cartilage ma...
Buckingham SH, Jeffcott LB.Methods for the non-invasive assessment of bone quality were used to monitor the osteopenia induced by immobilising a forelimb in a cast. These techniques included the measurement of ultrasound velocity, single photon absorptiometry and radiographic photodensitometry. Serial measurements were made before, during and after an eight week period of immobilisation of the left forelimb of four adult standardbreds in a light fibreglass cast which included the foot and extended above the carpus. The measurements continued for 12 weeks after the removal of the cast. The results indicated a trend to de...
Watrous BJ, Hultgren BD, Wagner PC.Thirty-six of 50 young equids examined at necropsy for gross pathologic and histopathologic evidence of osteochondrosis were determined to have lesions characteristic of this disorder in the distal joints of the tarsus. Abnormalities ranged from retained endochondral cores underlying undisturbed articular cartilage surfaces to clefts, subchondral osseous cyst-like lesions, and cartilage ulceration. Our findings supported the conclusion that osteochondrosis may cause spavin in the juvenile equid.
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.
Collatos C, Allen D, Chambers J, Henry M.An 8-year-old Arabian stallion had signs of severe tailhead pruritus and slowly progressive loss of tail tone for 3 months. Palpation per rectum and radiography of the sacrocaudal region revealed a transverse, ventrally displaced fracture of the caudal portion of the sacrum. Surgical decompression and tail amputation resulted in complete recovery of athletic and reproductive function. Evidence of cauda equina neuritis was not seen on histologic examination of nerve roots obtained at surgery.
Langton CM, Riggs CM, Evans GP.The velocity of ultrasound waves through bone has been used widely as a non-invasive method for assessing bone quality. Accurate measurement of velocity depends on accurate assessment of the distance travelled by the sound wave. It has been argued that the sonic pathway is deflected around the marrow cavity and so does not follow a straight line through the bone; therefore, correction factors have been developed to account for the extra distance travelled. This hypothesis was examined in vitro using sections from the equine third metacarpal bone. Two 1 MHz transducers used with the transmittin...
Young DR, Richardson DW, Markel MD, Nunamaker DM.The third carpal bone (C3) was collected from both forelimbs of 27 Thoroughbreds. On the basis of age, training, and history, specimens were assigned to 1 of 5 groups: yearling, untrained horses (group 1, n = 4); 2- to 3-year-old, untrained horses (group 2, n = 7); trained 2-year-old horses (group 3, n = 6); trained 3-year-old horses (group 4, n = 6); and 3-year-old, trained horses with carpal pathologic features (group 5, n = 4). A transverse section of subchondral bone 5-mm thick was cut in a precise fashion 10 mm below the proximal articular surface of all specimens. After high-detail radio...
Perdue BD, Collier MA, Dzata GK, Mosier DA.A one-year-old Thoroughbred filly was examined because of poor body condition and reluctance to move its neck. Complete blood count revealed leukocytosis (15,700 WBC/microliters) and hyperproteinemia (8 g/dl). Radiography of the cervical vertebrae revealed multifocal lesions of bone lysis surrounded by zones of sclerosis. The horse was euthanatized and necropsied. Granulomatous lesions were identified in the heart, spleen, lungs, bones, and lymph nodes. The multifocal granulomatous inflammatory lesions in this horse were suggestive of mycobacteriosis.
Vachon AM, McIlwraith CW, Keeley FW.Periosteal autografts were used for repair of large osteochondral defects in 10 horses aged 2 to 3 years old. In each horse, osteochondral defects measuring 1.0 x 1.0 cm2 were induced bilaterally on the distal articular surface of each radial carpal bone. Control and experimental defects were drilled. Periosteum was harvested from the proximal portion of the tibia and was glued into the principal defects, using a fibrin adhesive. Control defects were glued, but were not grafted. Sixteen weeks after the grafting procedure, the quality of the repair tissue of control and grafted defects was asse...
Blikslager AT, Wilson DA, Constantinescu GM, Miller MA, Corwin LA.A 1-year-old half-Arabian colt was referred for evaluation of a cranial cervical abnormality. Physical examination revealed the left wing of the atlas to be more ventral than the right wing. A head tilt, with the pole deviated to the left, was present because of the malpositioned atlas. Neurologic examination identified symmetrical weakness, ataxia, and proprioceptive deficits in all four limbs. Radiographs of the cranial cervical region revealed fusion of the atlas and axis, and deviation of the atlantoaxial joint to the left of the median plane. Euthanasia was elected. Necropsy confirmed the...
Yadernuk LM.A 13-year-old broodmare was referred for weight loss and left facial nerve paralysis. Bilateral temporohyoid osteoarthropathy was diagnosed based on proliferation of the temporohyoid joints and stylohyoid bones on radiographs and guttural pouch endoscopy. The left side was more severely affected. Treatment resulted in little or no improvement.
Harrison LJ, May SA, Richardson JD, Mills G, Dixon P.Four horses with an incomplete fracture of a hindlimb longbone were examined. In two, the tibia had been fractured by external trauma. In the other two horses proximal metatarsal 3 had fractured during normal activity. The diagnoses were made radiographically and the horses were treated conservatively by box rest. The fractures healed satisfactorily and the horses became sound.
McClure SR, Hillberry BM, Fisher KE.To evaluate in vitro holding power and associated microstructural and thermal damage from placement of positive-profile transfixation pins in the diaphysis and metaphysis of the equine third metacarpal bone. Methods: Third metacarpal bones from 30 pairs of adult equine cadavers. Methods: Centrally threaded positive-profile transfixation pins were placed in the diaphysis of 1 metacarpal bone and the metaphysis of the opposite metacarpal bone of 15 pairs of bones. Tensile force at failure for axial extraction was measured with a materials testing system. An additional 15 pairs of metacarpal bone...
Böhm D, Waibl H.Of 28 fractures of the first phalanx 21 were treated with osteosynthesis; one was treated conservatively. 2 to 4 compression screws have been applied, while the distal part of the limb was immobilized by a light cast bandage for 8 days. The implants were removed 2 to 3 months post operationem. All patients are again used in sports.
Dyson SJ, Greet TR.ALTHOUGH diaphyseal and distal metaphyseal fractures of
the equine humerus have been discussed in the literature
(Johnson, Lowe, Fessler and Amstutz 1974; Vaughan and
Mason 1975; Turner 1984), reports of humeral fractures of
other configurations are rare. Allen and White (1984) described
the successful surgical treatment of a chip fracture of the greater
tubercle of the humerus. This report describes the clinical
features and treatment of a fracture of the deltoid tuberosity.
Attenburrow DP, Goss VA.A case of acute destabilization of the right stifle joint associated with rupture of the anterior cruciate ligament and avulsion fracture of the tibial spine in a horse is reported. The diagnosis was obtained by scintigraphy and radiography. Post mortem investigations 6 weeks after injury demonstrated fibrillation of surface cartilage in regions unprotected by tibial menisci. No pathological change was demonstrated in the subchondral bone of the tibia in regions associated with loss of cartilage integrity.
Doige CE, Hoffer MA.Navicular bones from 74 horses were examined at necropsy. Animals ranged in age from eight months to 30 years. Eight horses had a clinical history of navicular disease. Degenerative lesions in the fibrocartilaginous surface of the navicular bone and of the surface of the deep flexor tendons were age related changes not necessarily related to lameness. These lesions were more extensive in horses with a history of navicular disease, and were often accompanied by adhesions and subchondral cavitation of the fibrocartilaginous surface of the navicular bone. Osteophytes, present in 12 of the 74 hors...
Olstad K, Hendrickson EH, Ekman S, Carlson CS, Dolvik NI.Describe the local morphological response of the articular-epiphyseal cartilage complex to surgical stab incision in the distal femur of foals, with emphasis on the relationship between growth cartilage injury, enchondral ossification, and repair. Methods: Nine foals were induced into general anesthesia at the age of 13 to 15 days. Four full-thickness stab incision defects were created in the cartilage on the lateral aspect of the lateral trochlear ridge of the left distal femur. Follow-up examination was carried out from 1 to 49 days postoperatively, including examination of intact bones, saw...