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Topic:Tendons
Tendons in horses are fibrous connective tissues that attach muscles to bones, facilitating movement and providing stability to the musculoskeletal system. They are composed primarily of collagen fibers, which confer strength and flexibility, allowing horses to perform various physical activities. Equine tendons are subject to significant mechanical stress during locomotion, making them susceptible to injury, particularly in performance horses. Common tendon injuries include strains, tears, and tendinitis, which can impact a horse's mobility and performance. This page compiles peer-reviewed research studies and scholarly articles that explore the structure, function, and pathology of tendons in horses, as well as advancements in diagnostic and therapeutic approaches for tendon injuries.
Effects of tendon grip technique (frozen versus unfrozen) on in vitro surface strain measurements of the equine deep digital flexor tendon. To determine effects of tendon grip technique on in vitro surface strain measurements of equine deep digital flexor tendon (DDFT) when loaded in tension. Methods: 12 hind limb DDFT from 8 adult horses (mean age, 9.8 years [range, 4.5 to 17 years]; mean body weight, 472 kg [range, 450 to 509 kg]), with no clinical evidence of hind limb lameness. Methods: After calibration, liquid mercury strain gauges were sutured to plantar surfaces of the tendons at distal (position 1), middle (position 2), and proximal (position 3) metatarsal regions. Each tendon was affixed to a materials testing machine (d...
Collagen fibril diameter distributions in ligaments and tendons of the carpal region of the horse. Since horses bred for the racing industry are subject to rigorous training procedures there is a real need to understand how the stresses experienced by their tendons and ligaments in vivo relate to the major load-bearing elements-the collagen fibrils. Consequently, an age-related study has been made of the collagen fibril diameter distributions of nine ligaments in and around the equine carpus. This is the first stage of a larger study aimed at understanding the ultrastructural changes that occur as a result of exercise. Most of the ligaments showed a bimodal diameter distribution at maturity...
The effect of the high palmar nerve block and the ulnar nerve block on lameness provoked by a collagenase-induced tendonitis of the lateral branch of the suspensory ligament. Controversy exists with respect to the innervation of the suspensory ligament (SL) in the fore limb of the horse. It is uncertain whether this structure is exclusively innervated by branches of the ulnar nerve or also to some extent by median nerve branches. Ground Reaction Forces (GRF) were determined in horses before and after the induction of a tendonitis in the lateral branch of the SL by the injection of collagenase, and before and after a high palmar and an ulnar block respectively. The high palmar block succeeded in bringing all GRF variables back to their original values which the ulna...
Ultrasonographic anatomy of the dorsal and abaxial aspects of the equine fetlock. This paper describes normal ultrasound images of the soft tissues of the dorsal and abaxial aspects of the equine fetlock. The palmar aspect of the fetlock is not discussed because it is related to the suspensory apparatus and flexor tendon anatomy which has been previously described. Ultrasound scanning was performed with 7.5 MHz linear or 10 MHz sector probes and recorded on 7.5 cm U-matic videocassettes allowing further retrospective data analysis, computer manipulation and good image reproducibility. Sagittal, parasagittal, frontal and transverse ultrasound scans of 13 lameness free mature...
Treatment and outcome of chronic tenosynovitis in three horses. Three horses were presented for treatment of chronic infections of the digital flexor tendon sheath. Clinical signs included severe lameness, and heat, pain and swelling of the digital flexor tendon sheath. The horses were treated with surgical lavage of the tendon sheath, systemic and local antibiotics, and analgesics. In each case, resolution of the lameness occurred over weeks to months. Only one horse returned to athletic activity, while the other two became comfortable at pasture. Response to treatment in cases of chronic tenosynovitis may not be as rapid or complete as that reported for ...
Kinematic differences between the distal portions of the forelimbs and hind limbs of horses at the trot. In literature, it has been hypothesized that the concussion at impact in the equine forelimb is larger than that in the hind limb, and therefore, eventually more clinical lameness may develop in the distal portion of the forelimbs. As the functional anatomy of the distal forelimb and hind limb segments is similar, a study was undertaken to compare the kinematics of hoof and fetlock in the forelimbs and hind limbs. For this purpose, the trot of 24 clinically normal (sound) horses on a treadmill (4 m/s) was recorded, using modern gait analysis equipment. It appeared that vertical hoof velocity a...
Effect of maturation and aging on material and ultrasonographic properties of equine superficial digital flexor tendon. Results of studies in human beings and other species have indicated that aging significantly influences the strength, modulus of elasticity, and energy storage ability of tendon. We wanted to determine the effects of aging on the material and ultrasonographic properties of equine superficial digital flexor (SDF) tendon. Ultrasonographic measurements of left forelimb SDF tendon cross-sectional area and mean echogenicity were made in 23 standing horses ranging in age from 2 to 23 years. All horses had not been in work for a minimum of 6 months prior to the study. After euthanasia, left forelimb ...
Ultrasonographic cross-sectional area and mean echogenicity of the superficial and deep digital flexor tendons in 50 trained thoroughbred racehorses. Fifty Thoroughbred horses were examined. All horses had been in race training for a minimum of 4 months before examination and had worked at racing speed; 24 horses had raced. All horses were clinically sound at the time of examination. Ultrasonography was performed, using a 7.5-MHz transducer with built-in fluid offset. Videotaped images of the palmar soft tissue structures were obtained at 4, 8, 12, 16, 20 and 24 cm distal to the base of the accessory carpal bone (DACB). Images were digitized, and each image was calibrated. Values for cross-sectional area (CSA) and mean echogenicity (ME) wer...
Ultrasonography as a method to determine tendon cross-sectional area. Ultrasonographic cross sectional area (CSA) measurements of equine superficial digital flexor (SDF) tendon were obtained to determine the feasibility of ultrasonography for CSA measurement of tendon in vivo and in vitro. Ultrasonographic measurements were compared with a more traditional CSA measurement method, ink-blot analysis. In addition, values for ultrasonographic SDF tendon mean echogenicity were obtained in vivo and in vitro. The left forelimb SDF tendons of 23 horses were evaluated ultrasonographically. Cross sectional images were acquired at 4-cm intervals distal to the base of the a...
Tendonitis of the deep digital flexor tendon in the distal metacarpal/metatarsal region associated with tenosynovitis of the digital sheath in the horse. Twenty-four horses with ultrasonographic evidence of tendonitis of the deep digital flexor tendon in the metacarpal/metatarsal region were seen over a 7 year period. Most horses had mild to moderate lameness and distension of the digital flexor tendon sheath in the affected limb. Intrasynovial analgesia of the digital flexor tendon sheath consistently improved the degree of lameness. Ultrasonography most commonly revealed small, distinct, often circular, focal hypoechoic areas within the deep digital flexor tendon which usually extended less than 1 cm proximodistally. The degree of lameness an...
Aseptic tenosynovitis of the digital flexor tendon sheath, fetlock and pastern annular ligament constriction. The anatomy of the digital flexor tendon sheath and related tendons and ligaments is described. Diagnosis and management of acute tenosynovitis and long-term tenosynovitis and associated tendon injuries are discussed, as well as the syndrome of stenosis of the fetlock canal (or fetlock annular ligament constriction) and palmar annular ligament constriction. Desmitis of the palmar annular ligament is also described.
Soft tissue injuries of the tarsus. Contrast radiography provides a clear survey of the size, shape, and location of extratendovaginal fluid-filled cavities, distended bursa, and tendon sheaths and demonstrates intersynovial communication. Ultrasonography effectively demonstrates Achilles tendon injury, slippage of the SDFT off the summit of the calcaneus, assorted ligamentous injuries, and cystic or solid extratendovaginal masses. It will also demonstrate distended bursae and tendon sheaths, but it is not as effective in demonstrating a synovial herniation, or a narrow synovial fistula. Contrast radiography may prove to be the ...
Tendon, tendon sheath, and ligament injuries in the pastern. The palmar (plantar) aspect of the pastern is an anatomically complex area and an understanding of this is a prerequisite for accurate diagnosis of injuries in this area. The gross and normal ultrasonographic anatomy are described, and injuries of the superficial and deep digital flexor tendons and the digital flexor tendon sheath, the distal sesamoidean ligaments, and the palmar ligaments of the proximal interphalangeal joint are discussed.
Miscellaneous conditions of tendons, tendon sheaths, and ligaments. The use of diagnostic ultrasonography has greatly enhances our ability to diagnose injuries of tendons and tendon sheaths that were previously either unrecognized or poorly understood. For may of these injuries, there is currently only a small amount of follow-up data. This article considers injuries of the deep digital flexor tendon and its accessory ligament, the carpal tunnel syndrome soft tissue swellings on the dorsal aspect of the carpus, intertubercular (bicipital) bursitis and bicipital tendinitis, injuries of the gastrocnemius tendon, common calcaneal tendinitis, rupture of peroneus (...
[Scanning electron microscopy of the synovial membrane of the distal phalangeal joint and the navicular bursa in horses]. 20 extremities of horses were used to investigate the synovial membrane of the distal interphalangeal joint and the navicular bursa. From each extremity five specimens were taken from the distal interphalangeal joint capsule, two further from the navicular bursa. Synovial villi were found near the articular cartilage as well as everywhere where the joint capsule did not form a tight periostal cover or was not connected with ligaments or tendons. Some lay between the articular surfaces of the phalanx media and phalanx distalis. Besides synovial villi and synovial folds "trabecular-like" cords o...
Vascular supply of the tendon of the equine deep digital flexor muscle within the digital sheath. The vascular and microvascular anatomy of the equine deep digital flexor tendon (DDFT) within the digital sheath was studied by injecting the vasculature with either colored latex or barium sulphate for radiographic, microangiographic, histologic, and computed tomographic (CT) evaluation. Consecutive 4-mm thick two-dimensional CT slice data were reconstructed to 3-dimensional volumetric images to enhance spatial evaluation of the blood supply. Gross dissection and angiographic studies identified three major vascular sources. Above the fetlock, the DDFT was supplied by either a branch of the me...
Transection of the accessory ligament of the superficial digital flexor muscle for the treatment of superficial digital flexor tendinitis in standardbreds: 40 cases (1988-1992). Medical records of 40 racing Standardbreds with superficial digital flexor tendinitis that underwent transection of the accessory ligament of the superficial digital flexor (SDF) muscle (superior check desmotomy) were reviewed. Surgery was performed bilaterally in 32 horses and unilaterally in 8. Concurrent palmar annular desmotomy was performed in 8 horses in which tendinitis involved the distal metacarpal region and confinement of the deep and SDF tendons by the annular ligament was suspected. Follow-up information was obtained for 32 horses, by telephone, and racing results were available f...
Digital flexor tendon lacerations in horses: 50 cases (1975-1990). The medical records of 50 horses examined because of lacerations of the tendon of the superficial or deep digital flexor muscle were reviewed to determine whether any injury or treatment factors could be associated with outcome. Median age of horses treated was 4.5 years (range, 1.5 years to 15 years), and the median follow-up time was 5 years (range, 1.5 to 16 years) after injury. Horses were considered to have survived if they were alive more than 1 year after injury. Twelve of 16 horses that had 1 or the other tendon transected survived; 13 of 16 horses that had both tendons transected surv...
Sensory innervation of the navicular bone and bursa in the foal. The sensory innervation of the navicular bone (os sesamoideum distale) and its suspensory ligaments [ligamenta sesamoidea collateralia (CSL) and ligamentum sesamoideum distale impar or distal sesamoidean impar (DS-impar) ligament] and the navicular bursa (podotrochlearis) was examined in the neonatal foal using immunocytochemistry. With antisera raised to substance P (SP) and human calcitonin gene-related peptide (CGRP), immunoreactive nerves were demonstrated to innervate the CSL and navicular bursa. Within CSL, and SP- and CGRP-like nerves were present in the synovial lining of the navicular...
The amino Acid sequence glutamine-628 to valine-646 within the A1 repeat domain mediates binding of von Willebrand factor to bovine brain sulfatides and equine tendon collagen. von Willebrand Factor (vWF) is a multifunctional glycoprotein in plasma and vascular subendothelial matrix which plays a major role in cellular adhesion. vWFdependent adhesion of platelets to the subendothelium at high shear rates involves a specific platelet membrane receptor, the glycoprotein (GP) Ib-IX complex. We have previously purified a 39/34-kiloDalton (kDa) dispase fragment of vWF (Leu-480/Val-481 to Gly-718) and demonstrated that this fragment contains the binding site for the GP Ib-IX complex [Andrews R K, et al. Biochemistry 1989; 28: 8326-83361. vWF also mediates agglutination of ...
Ultrasonographic morphology of the bicipital tendon and bursa in clinically normal quarter horses. The bicipital tendons and bursae of 25 healthy adult Quarter Horses were ultrasonographically examined. Cross-sectional images of the right and left bicipital tendons were obtained from each horse, using a 7.5-MHz transducer held in the frontal plane at the point of the shoulder. The bicipital tendon at the point of the shoulder appeared as a bilobate structure overlying the echogenic surface of the humerus. Median distance from the skin surface to the cranial surface of the tendon on the medial sagittal plane of the tendon was 23 mm (range, 16.5 to 30 mm); median distance on the lateral sagit...
The cross-sectional areas of normal equine digital flexor tendons determined ultrasonographically. Fifty-two animals, comprising 22 Irish Draught crosses (Group A), 15 Thoroughbreds (Group B) and 15 ponies (Group C) were examined ultrasonographically using a 7.5 mHz linear array probe and stand-off pad. All animals were free of tendon disease as determined from clinical and ultrasonographical examination. The superficial (SDFT) and deep (DDFT) digital flexor tendons were scanned at 7 transverse (axial) levels between the carpus and metacarpophalangeal joint. Each transverse image was digitised using a commercially available frame grabber and the cross-sectional areas of each tendon at each ...
In vitro mechanical properties of the accessory ligament of the deep digital flexor tendon in horses in relation to age. The material properties of the accessory ligament of the deep digital flexor tendon (AL) of 21 forelimbs from horses between ages one day and 15 years were determined. The force (634-11416 N), failure stress (45-138 N/mm2), failure strain (7-24%) and tangent modulus (33-1639 MPa) are presented in relation to age. Tangent modulus did not indicate changes in elasticity due to age. The results demonstrate that complete ligament failures (CLF) of ALs of older horses (mean 7835 N) occur at lower forces than ALs of young adult horses (mean 8894 N). Sudden decreases, 'dips', in the force-time curves ...
Three-dimensional sonographic imaging of the equine superficial digital flexor tendon. In a feasability study, a technique for constructing 3-dimensional sonographic images of the superficial digital flexor tendon (SDFT) was established in 6 clinically normal horses and applied to 7 horses with injured SDFT. Two-dimensional B-mode sonographic images were recorded on videotape as the sonographic transducer was manually moved along the palmar aspect of the metacarpal region. Selected videofields were digitized, and 3-dimensional images were constructed, using a computer work station and dedicated software program. The 3-dimensional images were of high quality and presented qualita...
Stringhalt secondary to trauma to the dorsoproximal region of the metatarsus in horses: 10 cases (1986-1991). A review of medical records was used to identify 10 horses in which stringhalt developed subsequent to trauma to the dorsal metatarsus. Six horses developed stringhalt within 3 months after injury, 3 horses developed stringhalt > 3 months after injury, and time from injury to stringhalt was unknown for 1 horse. Horses were treated with exercise, including daily hand-walking with pasture turnout, followed by lunging; or surgically, using lateral digital extensor myotenectomy. Of the horses treated with exercise, 1 had resolution of stringhalt, 2 improved but had residual stringhalt, and 1 ha...
Diagnostic techniques for identification and documentation of tendon and ligament injuries. Conventional clinical examination remains of medical and economic value for diagnosis of soft tissue injuries in the equine athlete. This procedure requires concentration and rigor to establish the diagnosis, and, if possible, some experience to better evaluate the prognosis. None of the new imaging techniques can replace the physical examination, but each may provide additional information. These sophisticated methods are bringing considerable progress in the knowledge of locomotor injuries in the horse and a tremendous improvement in our ability to diagnose precisely lamenesses and limitatio...
Superior check ligament desmotomy for treatment of superficial digital flexor tendonitis in thoroughbred and standardbred horses. Bilateral superior check ligament desmotomy was performed on 31 Thoroughbred and 17 Standardbred horses as the sole method of treatment for superficial digital flexor tendonitis. Horses resumed racing between 6 and 19 months after surgery. Horses that were able to compete in 5 or more races without injury to the tendon again were considered to have had a successful return to racing. Twenty-five Thoroughbreds were suitable for later study and 13 of these (52%) raced on 5 or more occasions. Fifteen Standardbreds were suitable for later study and 10 of these (66%) raced on 5 or more occasions. Wi...
The pathobiology and repair of tendon and ligament injury. Injury of the collagenous structures comprising tendons and ligaments, either from acute trauma or from repetitive strain lesions, results in protracted periods of disability. The resolution of such injuries often fails to restore the normal morphologic and functional characteristics of the structure and, therefore, either compromises the future performance of the individual or predisposes to an increased risk of recurrent injury.
Congenital abnormalities of tendons and ligaments. Congenital deformities of tendons and ligaments are not uncommon in foals. The vast majority of hyperextension deformities are treated successfully with exercise management and extended heel shoes. Successful treatment of contractural deformities depend on the site and severity of the deformity and on the appropriate use of medical, physical, and, possibly, surgical therapy.
