Tuber Sacrale Research Articles

Movement between the equine ilium and sacrum: in vivo and in vitro studies

Sacroiliac disease (SID) is an important cause of loss of performance in horses, yet little is known about the biomechanics of movement of the sacroiliac joint (SIJ). (a) To document the presence of equine SIJ motion by measuring the change in cross-sectional area (CSA) of the dorsal portion of the dorsal sacroiliac ligament (DSIL) during application of manual forces to the pelvis, and to ascertain if this varied between horses with SID and normal horses; (b) To determine the amount and direction of motion available at the equine SIJ using 3-D orientation sensors, and how motion is limited by the DSIL and sacrotuberous ligament. Study 1: CSA obtained ultrasonographically was compared before and during manual force application to the ilium, on a group of 10 horses, 5 with SID and 5 clinically normal. Study 2: direction and degrees of motion between sacrum and ilium were measured in 8 cadaveric SIJs. 3D orientation sensors were mounted to the fixated sacrum and the moveable ilium, and relative motion recorded between the 2 bones when manual forces were applied to the ilium. Study 1 showed a significant decrease in the CSA of the equine DSIL during application of manual forces to both tuber coxae (TC) (P<0.001) and tuber sacrale (TS) (P<0.001) when compared to at rest. Study 2 described range of motion to be greatest in the transverse or coronal plane, when lateral and oblique forces were applied to the pelvis, and recorded significant increases (P<0.05) in range of motion in the sagittal plane following resection of both the DSIL and sacrotuberous ligament. The change in DSIL CSA with application of manual force may be due to a lengthening of the ligament, reflecting equine SIJ motion in vivo. The motion recorded between ilium and sacrum in vitro suggests that greatest sacroiliac motion may occur in the transverse plane. Increases in range of motion following resection of ligaments give some indication of the role of each ligament.

Influence of individual competition level on back kinematics of horses jumping a vertical fence

The costs and investments required for the purchase and training of showjumpers justify the need to find selection means for jumping horses. Use of objective kinematic criteria correlated to jumping ability could be helpful for this assessment. To compare back kinematics between 2 groups of horses of different competition levels (Group 1, competing at high level; Group 2 competing at low level) while free jumping over a 1 m vertical fence. Three-dimensional recordings were performed using 2 panning cameras. Kinematic parameters of the withers and tuber sacrale (vertical displacement, vertical and horizontal velocities), backline inclination and flexion-extension motion of the 3 main dorsal segments (thoracic, thoracolumbar and lumbosacral) were analysed. Group 2 horses had a lower displacement of their withers and tuber sacrale from the end of the last approach stride until the first departure stride (P<0.05). As a result, they increased the flexion of their thoracolumbar and lumbosacral junctions during the hindlimb swing phase before take-off (P<0.05). However, withers and tuber sacrale velocities were slightly modified. Group 1 horses pitched their backline less forward during the forelimb stance phase before take-off and straightened it more after landing (P<0.05), probably indicating a more efficient strutting action of their forelimbs. Because significant differences in back motion were found between good and poor jumpers when jumping a 1 m high fence, criteria based on certain back kinematics can be developed that may help in the selection of talented showjumpers.

Development and validation of a periarticular injection technique of the sacroiliac joint in horses.

Sacroiliac joint osteoarthritis has been recognised as a significant cause of poor performance in competition and racehorses. Reliable diagnostic tools are currently lacking. The diagnosis has been based typically on exclusion of other possible causes of poor performance, back pain and hindlimb lameness. To develop a safe, reliable and minimally invasive periarticular or intra-articular injection technique of potential use for diagnosis and therapy of sacroiliac joint disease in horses. Twenty-six horses were used to develop and assess a medial approach to the sacroiliac joint with a 15 gauge, 25 cm long spinal needle. In Part I, the cadaveric study, the spinal needle was introduced cranial to the contralateral tuber sacrale and advanced along the medial aspect of the ipsilateral iliac wing until the dorsal surface of the sacrum was encountered. One ml methylene blue (MB) was injected in both sacroiliac joint regions of the sacropelvic specimens. The location of MB-stained tissues relative to the sacroiliac joints was recorded after dissection and disarticulation of the sacroiliac joint. In Part II, the in vivo study, 18 horses were used to validate the in vivo application of the sacroiliac joint injection technique. Horses were restrained in stocks and sedated in preparation for needle placement. One ml MB was injected bilaterally prior to euthanasia. Stained tissues were identified and recorded at necropsy. Successful joint injections were characterised as having MB located intra-articularly or < or = 2 cm periarticularly from the sacroiliac joint margin and localised to the middle or caudal third of the sacroiliac joint. Intra-articular MB was not observed in any specimen. However, MB-stained tissue was identified periarticularly in all injection sites (n = 48). Based on the predetermined success criteria, 96% of the methylene blue depots were located at the middle or caudal third of the sacroiliac joint. Dye-stained tissue was located < or = 2 cm from the sacroiliac joint margins in 88% of the specimens. Median distance of the MB from the sacroiliac joint margins was 1.0 cm (range 0.2-3.8 cm). The overall success rate considering both location and distance of the MB-stained tissue relative to sacroiliac joint margins was 83% (40 of 48 joints). The injection technique provides a reliable, easy to perform and consistent access to the medial periarticular aspect of the sacroiliac joint. The described injection technique has the potential for both diagnostic and therapeutic applications in the medical management of equine sacroiliac joint disease. Further investigation is necessary to evaluate clinical efficacy and potential adverse effects.

The sacroiliac joints: evaluation using nuclear scintigraphy. Part 1: The normal horse.

Sacroiliac (SI) disease is recognised as a cause of poor hindlimb action but differential diagnosis is often difficult. That in clinically normal horses there would be a significant difference in the ratio of radiopharmaceutical uptake (RU) between the fifth lumbar vertebra (L5) and each tuber sacrale (TS) and between L5 and each SI joint; and that these ratios would alter with age, but ratios would be bilaterally symmetrical. Dorsal scintigraphic images of the SI region of 15 horses, selected randomly from the clinic database, were analysed by 2 of the authors, comparing noncorrected and motion-corrected images. To determine scintigraphic anatomy, the scintigraphic images of 10 Thoroughbred horses were superimposed over a ventrodorsal radiographic image of an isolated pelvis. Dorsal scintigraphic images of 40 clinically normal horses age 3-16 years were evaluated using subjective examination, profile analysis and quantification using regions of interest. The tubera sacrale were seen as 2 well-defined oval regions immediately to the left and right of the midline, abaxial to which were larger, approximately oval areas with less RU, representing uptake in the SI joints. The definition between the SI region and the TS was more obvious in younger horses. Nonmotion-corrected images were often not of diagnostic quality or could be misinterpreted as abnormal. There were significant differences in RU between the TS and SI joints compared to L5, and decreased RU in the tubera sacrale with increasing age, but no change of uptake in the SI joint region and no effect of gender on RU. There was a high degree of left-right symmetry of the TS and SI joint regions. The scintigraphic images of horses with suspected sacroiliac joint disease should be compared with images of normal horses of comparable age. In normal horses, there was a high degree of symmetry; therefore, marked left-right asymmetry is likely to be abnormal.

The sacroiliac joints: evaluation using nuclear scintigraphy. Part 2: Lame horses.

Sacroiliac (SI) joint disease is difficult to diagnose definitively on clinical grounds. Lameness not attributable to SI joint pain may result in asymmetrical uptake of radiopharmaceutical in the tubera sacrale and SI joints; and that horses with clinical signs suggestive of sacroiliac joint disease would have differences in the ratios of radiopharmaceutical uptake between the fifth lumbar vertebra (L5) and either the tubera sacrale or SI joints compared with normal horses. To determine whether differences in radiopharmaceutical activity could identify individuals with presumed SI joint region pain. The scintigraphic appearance of the pelvic region of 234 horses (Group I) with lameness unrelated to the SI joints was compared with that for 40 normal horses (Group N) in full work and that for 41 horses with suspected SI joint disease (Group II). The effect of age, sex, lame limb and discipline were assessed in Group I. Motion-corrected scintigraphic images were assessed grossly, using profile analysis and by comparing ratios of uptake of mean count per pixel between L5 and each of the left (L) tuber sacrale (TS), right (R) TS, LSI and RSI joints. Left-right symmetry was compared. Lame horses (Group I) had greater asymmetry of radiopharmaceutical uptake in the tubera sacrale compared with normal horses. Horses with right hindlimb lameness had a larger RSI/LSI ratio compared to normal horses. In Group I L5/LTS, L5/RTS and L5/RSI increased with age, and there was a trend for L5/LSI to increase with age. In horses with presumed sacroiliac joint disease (Group II), L5/LTS, L5/RTS and L5/RSI were all greater compared with normal horses. Detection of marked left-right asymmetry by quantitative analysis or profile analysis was helpful in discriminating between those horses with clinical signs compatible with SI joint disease and either normal horses or those lame due to another cause. Scintigraphic evaluation of the SI region is useful to identify SI joint disease in combination with other clinical signs supportive of the diagnosis. However, diagnosis should not be based on this alone because of some degree of overlap in the range of radiopharmaceutical uptake between horses with SI joint disease and both normal horses and those with other causes of lameness.

Ultrasonographic abnormalities detected in the sacroiliac area in twenty cases of upper hindlimb lameness.

The pelvis is covered with extensive musculature and often presents a challenge in diagnostic imaging. Ultrasonography provides diagnostic information about soft tissue, articular cartilage and bone surfaces, although little information exists about the normal ultrasonographic appearance of the equine sacroiliac region. To determine the clinical applicability of ultrasonographic examination in horses with sacroiliac pain. Horses presented to the University of Minnesota Veterinary Teaching Hospital for hindlimb lameness were evaluated and lower limb lameness was ruled out with examination and local anaesthesia. Twenty cases were diagnosed with sacroiliac pain, characterised by response to palpation over the tuber sacrale. Seven of the 20 had visible asymmetry of the tuber sacrale. Ultrasonography was performed percutaneously and per rectum. Structures imaged were measured and compared to normal reference measurements. Other methods used to confirm diagnoses included thermography, scintigraphy and radiology. All 20 cases with sacroiliac pain showed ultrasonographic abnormalities of the sacroiliac area. Abnormalities were detected in the dorsal sacroiliac ligaments. Ligament size was significantly different from the normal ranges (P < 0.01). Malalignment of the sacroiliac area and sacral fractures were also imaged. Ultrasonography of the sacroiliac region aided diagnosis of ligament damage and displacement of bone surfaces; and may aid in monitoring the progression of healing. Diagnostic ultrasound is readily available to most practitioners. Therefore the findings of this study show that diagnosis of sacroiliac injuries is possible in the field.

THE SCINTIGRAPHIC ANATOMY OF THE EQUINE SACROILIAC JOINT

The aim of this study was to describe the scintigraphic appearance and location of the sacroiliac joint (SI-joint) in dorsal and dorso 30 degree lateral views of the equine pelvis in a scintigram. The pelvis from 10 different horses was prepared by attaching plastic tubes along relevant margins of the bone and around the SI-joint. A radioactive solution was injected into the tubes, and scintigraphic images were acquired with a gamma camera. Five specific landmarks were identified on the left and right sides of the pelvis. There was no significant difference in the distance measurements between the left and right sides in the dorsal view. The SI-joint was roughly ovoid in shape, with its long axis angled to the midline. The most craniolateral point of the SI-joint (Y) was located at the middle (SD = 0.04) of a line drawn from the caudal margin of the tuber sacrale (TS) to the craniolateral margin of the tuber coxa (TC), which was called TS-TC. In 85% of the specimens, the long axis of the SI-joint (SILA) was located caudal to or intersecting TS-TC, and the mean angle between SILA and TS-TC was 16.4 degrees (SD = 5.6 degrees). The distance from the caudomedial point of the SI-joint (Z) to Y was 0.38 times (SD = 0.04) the length of TS-TC. The distance from the tuber sacrale to the medial border of the SI-joint (TS-X) was 0.15 times (SD = 0.02) the length of TS-TC. In the oblique view, the SI-joint appeared wider and was positioned more laterally compared to the dorsal view. The distance TS-Y increased to 0.61 times (SD = 0.046) TS-TC, but SILA/TS-TC was essentially unchanged. The mean angle between TS-TC and SILA increased to 20.9 degrees (SD = 5.6 degrees). TS-X increased to 0.31 times (SD = 0.037) TS-TC. The location of the SI-joint was very similar in all horses, which makes it possible to estimate the location of the SI-joint in a scintigram in which the tuber sacrale and the craniolateral margin of the tuber coxa are identified.

Standardisation of muscular biopsy of gluteus medius in French trotters.

Morphometric measurements were taken from 41 French trotters of various ages and both sexes. Biopsy location was determined for the dorsal compartment as being one-third of the distance from the tuber sacrale to the tuber coxae and for the ventral compartment as being one-third of the distance from the tuber coxae to the caudal Cd1-Cd2 intervertebral joint. Ten horses were biopsied at these 2 sites at a sampling depth equal to half the total depth of the compartment as measured by ultrasonography. The percentage of slow and fast myosin heavy chain fibres was measured by using an immunoenzymatic method. The depth of the dorsal and ventral compartments of the gluteus medius was significantly greater in males than in females. The depth of the ventral compartment was greater in the case of a straight hip than of a wide hip and was greater in young horses than in older horses. The ventral and the dorsal compartments were composed in the mid-portion of 81.3 and 75.6% of fast myosin heavy chains, respectively. It was concluded that the locations and sampling depths in the gluteus medius could be standardised in French trotters by taking into account anatomical references, sex, age and width of the hip.

Modified ventilated capsule for the measurement of sweating rate in the exercising horse.

Modification of a ventilated capsule technique for the measurement of sweating rate (SR) is described for application in an exercising horse. The plastic capsule was sealed against the coat of the horse. Dry air was blown through the capsule over the skin and the change in absolute humidity (g/m3) between air entering and leaving the capsule was used to calculate SR. The effect of flow rate on the response characteristics of the system was investigated and measured over a range of sweating rates in a group of horses completing a short exercise test. Repeatability of SR measurements made at 2 sites, one 10 cm distal to the tuber sacrale (SRS) and the other approximately overlying C4 in the neck (SRN), were compared. To encourage the rapid and complete evaporation of moisture from the area of coat enclosed by the SR capsule, it was demonstrated that the degree of saturation of the air leaving the capsule should be maintained below 15% relative humidity (RH). This was best achieved at flow rates exceeding 35 l/min. No significant difference was found between the 2 repeated tests separated by 3 days, with respect to right atrial temperature (TRA) and SR. The modified system for the measurement of SR in the exercising horse used in this study was shown to be fast responding and capable of measuring a wide range of sweating rates. A good seal was maintained throughout and the capsule was removed without causing damage to the coat.

Head and trunk movement adaptations in horses with experimentally induced fore‐ or hindlimb lameness

The kinematic patterns of head and trunk were studied in horses during induced supporting limb lameness to understand the mechanisms horses use to compensate for lameness and to evaluate different symmetry indices for their significance as lameness indicators. Using the locomotion analysis system CODA-3 the kinematics of 11 clinically nonlame Dutch Warmblood horses were recorded while walking (1.6 m/s) and trotting (3.5 m/s) on a treadmill. A transient lameness model, evoking pressure induced pain on the hoof sole, was used to induce 3 degrees of fore- and hindlimb lameness. Peak vertical displacement, velocity and acceleration of head, withers, tuber sacrale and both tuber coxae were quantified at different phases of the stride. Changes in these variables due to lameness and symmetry indices calculated as quotients of the values during the lame and nonlame stance phase were analysed using a 2-way analysis of variance. The head, withers and tuber sacrale showed a similar sinusoidal pattern in their vertical displacement, velocity and acceleration. During both fore- and hindlimb lameness at the trot, the vertical velocity of the trunk at impact of the lame limb decreased (P < 0.05), during the lame stance phase the trunk was kept higher above the ground, maximal acceleration decreased and displacement amplitude was smaller than without lameness. Changes in movements of the head were much more expressed than movements of the withers during forelimb lameness and reversed during hindlimb lameness. At the walk, head movement patterns changed in the same way as at the trot, while withers and tuber sacrale patterns were hardly changed. Symmetry indices of all landmarks showed changes due to increasing lameness at the trot. The maximal vertical acceleration of the head and displacement amplitude of the tuber sacrale proved to be the best indicators to quantify a fore- and hindlimb lameness, respectively.

DUODENAL ULTRASONOGRAPHY IN THE NORMAL ADULT HORSE

Ultrasonography was used to evaluate the duodenum of 6 clinically normal horses. Examinations were performed in horses which each, alternatively, received diets of; 1) concentrates and hay, 2) hay only, or 3) after 36 hours of starvation. The duodenum was constantly visualized just ventral to the right kidney at the 16th and 17th intercostal spaces on a line joining the olecranon and tuber sacrale. Cranial to the 16th intercostal space visibility depended on thickness of interposing liver and lung field interference. Duodenal distensions, contractions and content are described. Starved horses had fewer contractions and distensions than horses on hay, or hay and concentrate diets but the difference was not significant. Duodenal wall thickness ranged from 3–4 mm. Ultrasonographically five layers, corresponding to the mucosal surface, mucosa, submucosa, muscularis propria and serosa, could be identified. A necropsy specimen of the duodenum was evaluated histologically and Ultrasonographically in a water bath for comparison.

Fracture of the wing of the ilium, adjacent to the sacroiliac joint, in Thoroughbred racehorses

During a two year period, sagittal fractures of the wing of the ilium were diagnosed in 10 Thoroughbred horses. All were spontaneous fractures sustained during normal exercise in training and racing, with no history of inciting trauma. When ultrasound scans of the surface of the pelvis were performed, the fracture was clearly visible as a discontinuity of the sacral wing of the ilium. In 3 horses, an irregular contour suggestive of periosteal callus was seen in the vicinity of the acute fracture. All horses examined by gamma scintigraphy had a focal increase in uptake of isotope just lateral to the tuber sacrale. Nine of the horses were treated conservatively by rest. The other horse had bilateral fractures and was subjected to euthanasia at the time of the injury. Six horses returned to full training, and 2 subsequently won, without recurrence of lameness.

Retrospective study of hindquarter asymmetry in Standardbred Trotters and its correlation with performance

SummaryFive hundred four‐year‐old Standardbred Trotters in training were examined in a study on the correlation between conformation, soundness and racing performance. In 39 horses marked hindquarter asymmetries were observed when they were standing squarely on all four feet. The asymmetries were seen as obvious height differences between the left and right tubera sacrale. In 30 cases the left tuber sacrale was lower and in nine cases the right tuber sacrale was lower. The horses showing hindquarter asymmetry were of significantly larger body size than the 461 horses not showing the asymmetry. There was no sex difference in the incidence of hindquarter asymmetry. The asymmetric horses had significantly lower total earnings, a lower number of races per horse and less good racing records (min/km) than the remaining 461 horses. The trainers reported that the asymmetric horses often had difficulties in performing at speed. In most horses, the asymmetry had not been observed until the examination. Past clinical records of 11 of the 30 asymmetric horses were available. In only one of the 11 horses had the asymmetry been considered of clinical importance. It was concluded that the described hindquarter asymmetries are important signs indicating that there is an enhanced risk that the affected horses will not become successful Trotters.