The vertebrae in horses form a critical component of the equine skeletal system, providing structural support and facilitating movement. Horses possess a series of vertebrae categorized into five regions: cervical, thoracic, lumbar, sacral, and caudal. These vertebrae protect the spinal cord and serve as attachment points for muscles and ligaments, contributing to the horse's posture and locomotion. Variations in vertebral anatomy can influence a horse's performance and susceptibility to certain conditions. This page compiles peer-reviewed research studies and scholarly articles that explore the anatomy, biomechanics, and clinical implications of vertebral health in horses.
Clayton HM, Townsend HG.A photographic method was used to measure axial rotation, dorsoventral flexion and extension and lateral bending at each intervertebral joint complex from the occiput to the first thoracic vertebra in spinal segments from 19 foals under 12 months of age and 14 horses over three years of age. Comparisons between the two groups showed that there was a general reduction in cervical spinal mobility with age. For the three types of movement at the eight joints tested, adults' mobility exceeded that of foals in only three cases (axial rotation and lateral bending at the A-O joint, and lateral bendin...
Clayton HM, Townsend HG.At least three types of movement, dorsoventral flexion and extension, axial rotation and lateral bending, were shown to occur at each of the intervertebral joints in the cervical spine. Between the first two cervical vertebrae the mean axial rotation was 107.5 degrees, which was 73 per cent of the total axial rotation of the cervical spine. The atlantooccipital joint rotated through a mean of 27 degrees, whereas the remaining cervical joints each had less than 3 degrees of rotatory movement. Dorsoventral flexion and extension were maximal at the atlantooccipital joint, which had an amplitude o...
de Lahunta A, Hatfield C, Dietz A.An unusual occipitoatlantoaxial malformation is described in a 2-week-old male part Arabian foal that was unable to stand at birth and showed signs of spastic tetraparesis due to a cervical spinal cord compression. There were 2 atlases present. One was fused to the occipital bones. The other articulated with the first atlas and an axis which had a long dens that projected into the vertebral canal. Examination of the ossification centers of the axis indicated partial duplication of that bone.
Klide AM.Lumbar and thoracic vertebrae of the extinct horse, Equus occidentalis, were examined for gross and radiographic evidence of overriding spinous processes. Of 2,661 vertebrae examined, 580 had intact spinous processes. Thirty-six intact spinous processes, which appeared grossly similar to overriding spinous processes in the modern domestic horse, E caballus caballus, were radiographed. Of these 36 vertebrae, 2 had radiographic signs compatible with a radiographic diagnosis of overriding spinous processes, ie, radiographically observed lysis and/or sclerosis. Seemingly, weight bearing or other s...
Bollwein A, Hänichen T.The cervical vertebral column of 103 horses of different age (42 weeks old fetus to 23 years) were examined with respect to age-related changes of the intervertebral disks. On gross examination the cervical intervertebral disks in the horse miss a pulpy nucleus but consist of a fibrocartilaginous tissue only, which is in contrast to literature. Age-related degenerative lesions as disintegration of connective tissue fibers leading to partial or complete loss of connection between the disks were found. In the more severe cases a yellow discoloration of the separated disks could be seen. Incidenc...
Gerber H, Ueltschi G, Diehl M, Schatzmann U, Straub R.For various anamnestic reasons the cervical vertebral column of 78 horses was examined radiologically. Statistical comparisons showed that male "warmbloods" were more frequently affected than was expected. Our horses were older than comparable animals in the international literature. Independently of their history the radiologic diagnosis of "cervical spondylarthrosis" was established in 56 horses. Arthrosis and other conditions were clinically manifested by spinal ataxia (44 horses) or mechanical impairment of the neck's mobility (21 horses). 10 of the arthrotic patients had synovial cysts ca...
Gaughan EM, Fubini SL, Dietze A.Over an 8-year period, 14 horses were admitted to the New York State College of Veterinary Medicine for evaluation of fistulous withers. Of the 14 horses, 11 were treated surgically and 3 were not treated. Surgical techniques involved radical excision of the affected soft tissue and spinous processes of affected vertebrae. Recurrence rate was 30%, and these horses required additional surgery to resolve the problem.
Nixon AJ, Stashak TS.Malalignment of the atlas and axis was seen in 4 horses with an idiopathic form of atlantoaxial subluxation characterized by spinal cord compression on extension. The bone structure and density of the atlas and axis were radiographically normal in 3 of the 4 horses. Clinical signs appeared when the horses were 6 to 30 months old, and 3 of the 4 horses had a history of trauma. Although a congenital anomaly could not be ruled out, the cause was thought to be trauma. The horses were moderately to severely ataxic at the time of examination. Myelography revealed compression of the spinal cord at th...
Stadler P, van den Berg SS, Tustin RC.A Hansen type I cervical intervertebral disc prolapse was diagnosed in a 16-year-old American Saddler showing clinical signs of paresis and ataxia. An ante-mortem diagnosis was made by means of plain radiographs and a myelogram. The horse was euthanased and the diagnosis confirmed on a post-mortem examination.
Hartmann E, Baumgärtner W, Hungerland C.The present report describes the clinical and pathological findings of a one year old foal presented with paralysis of the hind legs. Macroscopically and histologically, a lymphosarcoma in the vertebral body and the adjacent epidural space of T 16, in the spleen and the mesenterial lymph nodes was observed. The adjacent spinal cord showed focal degenerative changes characterized by dilatation of myelin sheaths, swollen axons and few macrophages.
Kannegieter NJ, Alley MR.A 20-month-old, Standard-bred colt was presented with an acute onset of hindlimb ataxia. Clinical and radiographic examination identified a compressive lesion affecting the spinal cord at the level of the 17th to 18th thoracic vertebrae. After euthanasia, post-mortem examination revealed a tumour in the epidural space, diagnosed histologically as a lymphosarcoma. Neoplastic lymphoid cells were also present in the abdominal lymph nodes and brain. Because of the disseminated nature of lymphosarcoma in the horse, involvement of the central nervous system is likely to be more common than is presen...
Boyd JS.A radio-opaque marker was injected intramuscularly at different levels and with needles of different lengths into the cervical musculature of a series of ponies and horses which were under profound anaesthesia prior to euthanasia. Subsequently the necks were sectioned and radiographed to determine the fate of the injected material. The results indicated that care was necessary in the selection of the level for injection in order to prevent deposition of material on to the periosteal surface of the cervical vertebrae or on to the ligamentum nuchae and fascial sheaths. The muscle mass over the t...
Wagner PC, Grant BD, Reed SM.Cervical vertebral malformations are recognized clinically when they result in spinal cord compression causing neurologic deficits. Confirmation of diagnosis is based on radiographic and myelographic evidence of cord compression. Medical therapy is not usually successful. Several successful surgical treatments are described.
Powers BE, Stashak TS, Nixon AJ, Yovich JV, Norrdin RW.Specimens of ligamentum flavum, joint capsule, and dorsal lamina were collected at surgery or necropsy from 25 horses with cervical static stenosis. All horses had myelographic evidence of dorsal compression of the spinal cord caused by soft tissue and/or bone in the caudal cervical area, primarily at C6-7. Most horses also had radiographic evidence of degenerative joint disease of articular facets. Histologically 19 horses had osteosclerosis and cartilage retention in the dorsal lamina, and 24 horses had increased fibrocartilage at the ligamentum flavum attachment to dorsal lamina. The ligame...
Markel MD, Madigan JE, Lichtensteiger CA, Large SM, Hornof WJ.Over a 4-year period, vertebral body abscess was diagnosed in 5 young cattle. The laboratory findings in most of these cases did not suggest a diagnosis of vertebral body abscess. The most important basis for diagnosis of this condition was a thorough neurologic examination. In 4 cases, necropsy revealed abscesses in the lungs or thoracic cavity as well, suggesting that a history of pneumonia preceding paresis may favor the diagnosis of vertebral body abscess.
Townsend HG, Leach DH, Doige CE, Kirkaldy-Willis WH.The relationship between spinal biomechanics and pathological changes occurring in functionally normal equine thoracolumbar spines was studied in 23 horses. Ventrolateral vertebral body osteophytes occurred in 36 per cent of the spines. The majority occurred between the 10th and 17th thoracic vertebrae with the largest being found between the 11th and 13th thoracic vertebrae, the region of the thoracic spine where the greatest amount of lateral bending and axial rotation occurs. Impingement of the dorsal spinous processes was detected in 86 per cent of the spines with most lesions occurring be...
Yovich JV, Powers BE, Stashak TS.The intervertebral disks and adjacent vertebral bodies of the 2nd to 7th cervical vertebrae from 17 horses (3 months to 19 years of age) were examined grossly and by light microscopy. In each specimen, the disk tissue was fibrocartilagenous centrally and became more fibrous peripherally, but without a distinct demarcation between the nucleus pulposus and anulus fibrosus. Demarcation between the anulus fibrosus and the dorsal longitudinal ligament was not apparent. With increasing age of the horses, cellularity of the central fibrocartilagenous portion of the disk decreased. The caudal end plat...
Chiapetta JR, Baker JC, Feeney DA.An Arabian foal, which was recumbent for 4 days, had signs of extensor rigidity of the thoracic limbs and hypotonic paralysis of the pelvic limbs. Survey radiography revealed a lesion at T15, with radiographic impression of a compression fracture or a hemivertebra. Postmortem examination revealed a fracture at T15. Clinical and pathologic findings in this case were compatible with the Schiff-Sherrington syndrome, which is characterized by thoracic limb extensor hypertonia associated with paraplegia from acute thoracolumbar trauma.
Adams SB, Steckel R, Blevins W.Diskospondylitis was diagnosed in 5 horses admitted to the Purdue University Large Animal Clinic during a 3-year period. Each horse had evidence of cervical pain. Clinical signs and radiography were useful for identifying the diskospondylitis. Cerebrospinal fluid was normal.
Townsend HG, Leach DH.The anatomical features of 21 equine thoracolumbar spines, obtained from horses with clinically normal backs, were examined and the results compared with recent data on the mobility of the joint complexes of the horse's spine. The thoracolumbar spine can be divided into four regions based upon the morphology of the joint complexes: the first thoracic intervertebral joint (T1-2), the cranial and mid thoracic region (T2-T16), the caudal thoracic and lumbar region (T16-L6) and the lumbosacral joint. The mobility of the intervertebral joints in each of these regions can be related to their morphol...
DeBowes RM, Grant BD, Bagby GW, Gallina AM, Sande RD, Ratzlaff MH.A modified form of the Cloward technique for anterior cervical fusion in human beings was used in the application of different grafts for evaluation of their effectiveness in stabilizing equine cervical vertebrae. Results of bovine xenograft implants in 8 horses were compared with results of stainless steel baskets (SSB) packed with cancellous autogenous bone in 8 horses. Graft material was incorporated in all cases. Evidence of graft rejection was not present. Both forms of implants decreased the mobility of the intervertebral space in which they were implanted. A fibrous connective tissue un...
Alitalo I, Kärkkäinen M.Ataxia caused by a focal compression of the cervical spinal cord was diagnosed in four young standardbred trotting horses. Diagnosis was verified by myelography. Changes in the cervical vertebral column were studied using microradiographic and histologic methods. In the vertebrae involved, there was irregularity of the cartilaginous growth zone, cracks with a loose fragment and disturbance in the enchondral ossification. These changes resemble osteochondrosis. Porous appearance in lateral and ventral funiculi as well as mural calcified plaques in the small vessels of the white matter were foun...
Foss RR, Genetzky RM, Riedesel EA, Graham C.Two horses with ataxia of all four limbs were found to have cervical intervertebral disc protrusion. Severe pelvic limb ataxia, proprioceptive deficits and spasticity were present in both horses with similar but less severe signs in the thoracic limbs. Cerebrospinal fluid analysis was within normal limits. Metrizamide myelography allowed definitive diagnosis in one case when a compression of the spinal cord was demonstrated at the level of the second intervertebral space. In the second case, an intervertebral disc protrusion between cervical vertebrae 6 and 7 was found at necropsy. Fiber degen...
Doige CE.A midsagittal centrum cleft of T5-6, malformation and fusion of T3-7, intra- and extraspinal cyst, and myelodysplasia were found in a 3-month-old female Arabian foal that had experienced posterior ataxia since birth. Based on studies in other species, ecto-endodermal adhesions early in embryogenesis leading to formation of an enterogenous cyst is the most probable pathogenesis.
Hartmann E, Baumgärtner W, Hungerland C.The present report describes the clinical and pathological findings of a one year old foal presented with paralysis of the hind legs. Macroscopically and histologically, a lymphosarcoma in the vertebral body and the adjacent epidural space of T 16, in the spleen and the mesenterial lymph nodes was observed. The adjacent spinal cord showed focal degenerative changes characterized by dilatation of myelin sheaths, swollen axons and few macrophages.
Crowhurst RC.Diseases of the back of horse and man are not comparable owing to the great difference in anatomy and posture. Veterinary surgeons, particularly in the United Kingdom, are often requested to account for a poor performance due to suspected "back trouble" but a complete examination of the horse's back is most difficult and care must be taken first to exclude any limb or foot lesions. Diseases of the bones, nerves and muscles are briefly discussed. Diagnosis must be improved by new radiographic and biochemical tests before the significance of back lesions can be assessed or even treated.
Mackie MK.A 13-year-old, Thoroughbred gelding presented with a 3-year history of progressive ataxia of all 4 limbs. Physical and neurological examinations indicated a compressive lesion affecting the cervical spinal cord. Radiographs confirmed a lesion, and a myelogram a narrowing of the spinal canal at cervical vertebrae (6-7). Necropsy confirmed cervical stenotic myelopathy.
Kero T, Kuussaari J.The purpose of this communication is to report the first diagnosed case of spinal ataxia in the horse in Finland. The horse was atactic and had a wobbling gait. Especially in turning and backing the rear legs tended to swing outwards. Macroscopical studies revealed malformation of the cervical vertebral articular facets and narrowing of the cervical vertebral canal. The vertebral malformation caused the degeneration of the spinal cord, through the compression of the cord. In this paper the macroscopial and microscopical findings are discussed and compared with the findings of other authors.
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.
Clayton HM.The horse's head and neck account for about 10% of body weight, and this, combined with the fact that they are cantilevered in front of the trunk, produces considerable leverage around the joints at the base of the neck. During locomotion, the neck is moved primarily by gravitational and inertial forces controlled by eccentric-concentric cycles of contraction in the topline muscles assisted by energy-saving, stretch-recoil cycles in the nuchal ligament. The functional part of the nuchal ligament is the caudal funicular region and the lamellae to the second cervical vertebra that acts as the po...
Peter V, Marr C, Foote A, Auer H, Head M.This case report describes a 13-year-old cob-cross gelding presented for evaluation of recent onset hindlimb ataxia. The gelding had undergone general anaesthesia and tenoscopy of the right hindlimb digital flexor tendon sheath at a nearby clinic three months earlier and had appeared normal at routine post-operative assessments until the sudden onset of neurological deficits. Spinal trauma was suspected initially but radiography and scintigraphy were unremarkable. Due to the severity and progressive nature of the clinical signs the -gelding was subjected to euthanasia. Post mortem examinations...
Mannaa M, Shamaa AA, Shawky A, Hassan IM, Refaey AM, Abu-Seida AM.Cervical vertebral stenotic myelopathy (CVSM), also known as equine wobbler syndrome or cervical ataxia, is a devastating neurological syndrome resulting from compression of the spinal cord at the cervical region. This report describes a novel surgical technique for treatment of 16-month-old Arabian filly with CVSM. The filly showed grade 4 ataxia, hypermetria, weakness of the hind limbs, stumbling during walking, and abnormal gait. Case history, clinical signs and myelography revealed spinal cord compression between the C3 and C4 and C4-C5. The filly underwent a novel surgical interference fo...
Riddell LP, Yoshimura S, MacKay AV, Wilson DG.A 17-year-old Quarter horse mare was presented because of traumatic luxation of the fifth sacral and first coccygeal vertebrae resulting in loss of sensation, motor function, and perfusion of the tail. The case was complicated by an associated tail head hematoma. Due to the severity of the injury, tail amputation was performed at the level of the luxation. Tail amputations in horses at the sacrococcygeal junction following a suspected tail pull injury are infrequently reported in the literature. . Une jument Quarter horse âgée de 17 ans fut présentée pour cause de luxation traumatique de l...
Shrauner B, Blikslager A, Davis J, Campbell N, Law M, Lustgarten M, Prange T.The large size of the adult horse prevents the use of advanced imaging modalities in most areas of the axial skeleton, including the lumbosacral vertebral column. Traditional imaging techniques are frequently unable to pinpoint the underlying pathology in horses with caudal back pain. In man, lumbosacral epiduroscopy is used to diagnose and treat subjects with chronic back and leg pain. This technique may close the diagnostic gap in horses with similar clinical signs. Objective: To evaluate the safety and feasibility of lumbosacral epiduroscopy in the standing adult horse. Methods: Descriptive...
Kondo T, Sato F, Tsuzuki N, Chen CJ, Yamada K.Computed tomographic myelography can be a useful tool for evaluating vertebral canal stenosis. However, an index of spinal cord compression is yet to be established. This observational descriptive study aimed to establish an index for spinal cord compression using computed tomography (CT). Twenty-three Thoroughbred horses (age, 155-717 days; weight, 205-523 kg) with suspected cervical vertebral malformation were subjected to computed tomographic myelography in dorsal recumbency using large-bore gantry CT to define the entire cervical vertebrae from C1 to C7. Subsequently, the height of the sp...
Chiapetta JR, Baker JC, Feeney DA.An Arabian foal, which was recumbent for 4 days, had signs of extensor rigidity of the thoracic limbs and hypotonic paralysis of the pelvic limbs. Survey radiography revealed a lesion at T15, with radiographic impression of a compression fracture or a hemivertebra. Postmortem examination revealed a fracture at T15. Clinical and pathologic findings in this case were compatible with the Schiff-Sherrington syndrome, which is characterized by thoracic limb extensor hypertonia associated with paraplegia from acute thoracolumbar trauma.
Kondo T, Mashimo Y, Sato F, Tsuzuki N, Yamada K.Thoroughbred horses appear to be particularly predisposed to cervical vertebral stenotic myelopathy (CVSM), also known as wobbler syndrome. We hypothesized that variations in the cervical vertebral volumes can affect the dynamic instability of the cervical vertebrae. This observational study aimed to clarify whether cervical vertebral volume could be considered as a contributing factor in CVSM in Thoroughbred horses. Computed tomography (CT) was used to investigate a total of 21 male Thoroughbred horses (age range, 217-1,002 days; mean, 542.3 days). The study population comprised 17 CVSM horse...
Tomizawa N, Nishimura R, Sasaki N, Kadosawa T, Senba H, Hara S, Takeuchi A.Cervical myelography and survey radiography was performed on 12 light breed wobbling foals and a new radiographic measurement method was applied for more accurate diagnosis of cervical vertebral instability. Ratios of stenosis of the spinal canal on survey radiography and myelography using relative values in an individual foal were defined on radiograms of lateral flexed position of mid-cervical region, and coincidence between the ratios and histopathological lesions in the cervical spinal cord was investigated. Five of 6 foals had ratios of stenosis on myelography more than 40% at the interve...
Collar EM, Zavodovskaya R, Spriet M, Hitchens PL, Wisner T, Uzal FA, Stover SM.To gain insight into the pathophysiology of equine lumbar vertebral fractures in racehorses. Objective: To characterise equine lumbar vertebral fractures in California racehorses. Methods: Retrospective case series and prospective case-control study. Methods: Racehorse post mortem reports and jockey injury reports were retrospectively reviewed. Vertebral specimens from 6 racehorses affected with lumbar vertebral fractures and 4 control racehorses subjected to euthanasia for nonspinal fracture were assessed using visual, radiographic, computed tomography and histological examinations. Results: ...
Alitalo I, Kärkkäinen M.Ataxia caused by a focal compression of the cervical spinal cord was diagnosed in four young standardbred trotting horses. Diagnosis was verified by myelography. Changes in the cervical vertebral column were studied using microradiographic and histologic methods. In the vertebrae involved, there was irregularity of the cartilaginous growth zone, cracks with a loose fragment and disturbance in the enchondral ossification. These changes resemble osteochondrosis. Porous appearance in lateral and ventral funiculi as well as mural calcified plaques in the small vessels of the white matter were foun...