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J M Denoix

Publications and source records attributed to J M Denoix.

At least 37 records · Page 2Linked to original sources
PubMed1999

Ultrasonographic anatomy of the accessory ligament of the superficial digital flexor tendon in horses.

The ultrasonographic anatomy of the accessory ligament of the superficial digital flexor tendon (AL-SDFT) in the horse is presented. Comparison between anatomical sections of isolated limbs and ultrasound scans of the distal antebrachium in sound horses enabled the authors to establish the normal reference ultrasonographic images of this structure. The AL-SDFT inserts 7-14 cm above the antebrachiocarpal joint on the palmaromedial aspect of the radius. Ultrasonographically it appears as an uniformly echogenic structure located deep to the median artery. The knowledge of ultrasonographic anatomy is essential for identification of abnormal images and assessment of AL-SDFT damage.

Animals↗
PubMed1999

Kinematics of the equine back: flexion-extension movements in sound trotting horses.

This study was undertaken to evaluate the flexion-extension movements of the back in a group of sound trotting horses. Using a 3-D kinematic analysis system, 13 clinically sound horses fitted with 5 skin markers placed on the dorsal midline of their trunk were recorded while trotting on a track in the conditions of the routine lameness examination. These markers were used to calculate 3 back angles (thoracic, thoracolumbar and lumbosacral angle). These back angles were then filtered using Fourier series. To evaluate the repeatability of flexion-extension movements, the intra- and inter-individual variabilities were studied. The angle-time diagrams showed that the equine back extended during the first part of each diagonal stance phase and flexed during the second part of each diagonal stance phase. The ranges of motion were less than 4 degrees for the 3 back angles. The intra- and inter-individual variability values of maximal extension and maximal flexion time points were similar and extremely low. This demonstrates the high repeatability of the temporal pattern of flexion-extension movements of the back. Intra- and inter-individual variabilities of the range of motion showed that the back mobility varies more in-between horses than between trials of the same horse. Compared with electromyographic activities of back muscles reported in the literature, flexion-extension movements described in this study tend to show that, at a slow trot, trunk muscles act mainly to limit flexion-extension movements of the back rather than to induce movements.

Animals↗
PubMed1999

Correlation between surface electromyography and kinematics of the hindlimb of horses at trot on a treadmill.

The purpose of this study was to demonstrate the feasibility of surface electromyography in the horse and to correlate electromyographic activity with kinematic data. Surface electromyography of seven hindlimb muscles was recorded in five horses at trot on a treadmill. Simultaneously, kinematic analysis of the hindlimb was performed using a three-dimensional system and a unidirectional accelerometer was attached to the hoof. Electromyographic activities of the gluteus medius, vastus lateralis and two parts of the biceps femoris started in the late part of the swing phase and ended in the late period of the stance phase or the early period of the next swing phase. The semitendinosus showed two bursts of activity. The tensor fasciae latae acted when the previous muscles were inactive. Activity of the extensor digitorum longus was of low level but lasted during most of the step cycle. Correlation between electromyography, kinematics and anatomy helps us to understand the complex role of biarticular muscles: the tensor fasciae latae flexes the hip joint during the swing phase and extends the stifle joint during the stance phase, whereas the semitendinosus extends the hip joint during the stance phase and flexes the stifle joint during the swing phase. Cranial and caudal regions of the biceps femoris were also found to be bifunctional. Surface electromyography correlated with kinematic analysis gives valuable information about the functions and the timing of activity of the hindlimb muscles.

Animals↗
PubMed1998

Asymmetry in placement of bilateral skin markers on horses and effects of asymmetric skin marker placement on kinematic variables.

OBJECTIVE: To evaluate asymmetry in placement of bilateral skin markers on horses and to determine effect of asymmetric skin marker placement on kinematic variables for trotting horses. ANIMALS: 10 horses for evaluation of asymmetry in marker placement; 1 horse for evaluation of effects on kinematic variables. PROCEDURE: Asymmetry in marker placement was assessed by attaching markers to horses and comparing radiographs of left and right limbs. An experimental model was developed to determine effects on kinematic variables; accuracy of the model was validated experimentally. Using kinematic data from a clinically normal trotting horse as reference data, effects of asymmetric marker placement on vertical displacement-time and joint angle-time diagrams were determined by use of the model. RESULTS: Asymmetry of placement was < 1 cm for markers on the distal portions of the limbs and < 2 cm for markers on the proximal portions. Asymmetric marker placement did not alter general shapes of the vertical displacement-time and joint angle-time curves. In most instances, largest differences in vertical displacement attributable to asymmetric marker placement were equal to or less than magnitude of the asymmetry of placement. Alterations in joint angle-time curves were mainly a result of shifting of the curves on the Y axis. Joint range of motion was only slightly changed by asymmetric marker placement, but maximum flexion and extension angles were greatly altered. CONCLUSIONS AND CLINICAL RELEVANCE: Some kinematic variables can be greatly altered by small differences in skin marker placement. Such effects should be taken into account when evaluating kinematic data for sound and lame horses.

Animals↗
PubMed1998

Mechanical correlations derived from segmental histologic study of the equine superficial digital flexor tendon, from foal to adult.

OBJECTIVE: To assess histologic variations of the equine superficial digital flexor tendon (SDFT) according to site and to horse age and activity, and to correlate these data with reported segmental mechanical results. SAMPLE POPULATION: Superficial digital flexor tendons isolated from 42 horses 0.5 hour to 23 years old. PROCEDURE: 7 segments of each SDFT were delimited and submitted for conventional histologic examination. Each segment was examined and graded for fiber undulation, cellularity, number and size of interfascicular connective spaces (ICS), presence or absence of focal and diffuse chondroid metaplasia, and differentiation of the dorsal (DB) and palmar (PB) borders of the tendon. RESULTS: Fiber undulation and cellularity significantly decreased with age. The proximal and middle metacarpal segment fibers were significantly less undulated and their ICS were smaller than those of the other segments, especially in old horses. Focal chondroid metaplasia developed from 5 years onward, mainly in the sesamoidean segments. Diffuse chondroid metaplasia was characteristic of the digital region in horses > 6 years old. The DB of the metacarpodigital region tended to differentiate into fibrocartilage in association with age. The PB was generally differentiated as nonfascicular dense connective tissue. Activity induced a decrease in the number and size of the ICS. CONCLUSIONS: The lesser undulation of the proximal and middle metacarpal segments fibers can be correlated to their mechanical behavior (stress-strain curve) and relative weakness within the SDFT. Focal chondroid metaplasia and fibrocartilage on the DB are normal features, related to the compression stresses undergone by the sesamoidean region of the tendon.

Aging↗
PubMed1997

Ultrasonographic examination of the proximal scutum in the horse.

Normal and abnormal ultrasonographic images are presented of the proximal scutum (proximal sesamoid bones and palmar ligament) in the horse. Comparison between anatomical sections, MRI (magnetic resonance imaging) and ultrasound scans enabled the authors to establish the normal ultrasonographic anatomy of the palmar fetlock. Nine cases of proximal scutum injuries were identified ultrasonographically, of which 4 are illustrated. On normal limbs, the facies flexoria of the proximal sesamoid bones appeared as a thin and regular hyperechoic line and the palmar ligament was regularly echogenic. Lesions of the proximal scutum, that could be documented ultrasonographically, included rupture of the palmar ligament, avulsion fractures of the proximal sesamoid bones and palmar ligament desmopathy. Thinning or degeneration of the palmar ligament, concurrent with osteolysis of the proximal sesamoid bones, were indicative of palmar ligament enthesopathy. Ultrasonographic examination provided essential information for an accurate diagnosis of proximal scutum damage.

Animals↗
PubMed1997

Mechanical properties of pathological equine superficial digital flexor tendons.

The objective of this study was to mechanically characterise superficial digital flexor tendon (SDFT) lesions. Eight pathological SDFTs, isolated from 6 adult horses, were tested in traction until rupture (at 1 mm/s). The stresses and strains simultaneously undergone by each of the 7 segments of a tendon were determined throughout the test, and the modulus of elasticity of each segment was evaluated from the segmental stress-strain curve thus obtained. These mechanical data were compared to those obtained on 10 normal SDFTs. After the test, the tendinous segments were submitted to a histological examination in order to characterise the tissues. Three lesional categories (I to III, of increasing maturity), as well as the normal tendinous tissue, were defined and assessed quantitatively according to their extent in the histological sections. The most recent and severe lesions (categories I and II) were correlated with a large degree of hypertrophy (often above 200%) of the corresponding segments, with a resulting decrease in the stress at tendon rupture, and a slight decrease in the strain at tendon rupture in spite of a low modulus of elasticity (low stiffness). In contrast, the adjacent areas, less or not injured, underwent compensatory strains. This relative overstraining was especially critical with category III tissue, often present in the transitional areas between sound and severely injured segments. Here the modulus of elasticity was low whereas the hypertrophy was only slight. Therefore, the corresponding segments seemed to be the most fragile sites, and those most predisposed to recurring injury, in an injured SDFT.

Analysis of Variance↗
PubMed1997

Variability of the limb joint patterns of sound horses at trot.

The reproducibility of gait variables for sound horses is essential for the interpretation of their modifications by locomotor disorders. Therefore, the purpose of this study was to evaluate the variability of the limb joint angle patterns in a population of sound horses while they trotted in the conditions of the routine lameness examination (slow trot, just held by hand, on a track, outdoors). The kinematics of 14 French Saddle horses was recorded using a 3-dimensional (3D) kinematic analysis system. Angle-time diagrams were established in the sagittal plane and their intra- and inter-individual variabilities were evaluated for the whole stride. Horses spontaneously repeated tests at constant speed. The intra- and inter-individual variabilities were low. These values were different from one joint to another and they increased distally. The maximum values were reached by the fetlock and coffin joints. Inter-individual compared to intra-individual variability was 0.9 to 1.9 times greater. There was a high correlation between mean angle-time and mean individual diagrams established for the whole population. It was concluded that it is possible to repeat similar tests with horses trotting in the conditions of the lameness examination. In an homogeneous population, each horse adopts a constant angular pattern that is very close to that of other horses. Since mean angle-time diagrams established on a sound population are highly representative of each mean individual angle pattern, they can be considered as reference data for the further analysis of the pathological gait.

Animals↗
PubMed1997

Kinematic analysis of the locomotion symmetry of sound horses at a slow trot.

This study of the locomotion symmetry was undertaken to provide standard symmetry indices of a group of sound horses at the trot. Using a 3D data collection system, the kinematics of the limb joints of 13 clinically nonlame horses were recorded while trotting in the standard conditions of the clinical lameness examination. A kinematic symmetry indice based on an inter-correlation method was defined and applied to the vertical displacement-time and joint angle-time diagrams of the left and right joints of the horses. For each horse, the mean symmetry indice of each joint was calculated using values from 5 trials. For each joint, these means were then averaged. To evaluate the repeatability of the locomotion symmetry, the intra- and inter-individual variabilities of the symmetry indices were studied. The levels of symmetry of the markers of the trunk were generally lower than those of the limbs. Moreover, during the 5 trials these levels of symmetry were strongly variable but their mean values were very similar from one horse to another. In our experimental conditions the trunk presented a higher degree of freedom than the limbs. This high intra-individual variability indicated also that several trials are necessary to quantify the locomotion symmetry of a trotting horse. In the same way, a lower level of symmetry of the hindlimbs, compared to the forelimbs, was proved by their lower values of symmetry indices. As opposed to the supporting role of the forelimbs, the propulsive role of the hindlimbs may explain this feature.

Animals↗
PubMed1996

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 horses were compared to anatomically dissected leg specimens, anatomical sections and Magnetic Resonance Imaging scans of isolated limbs. The results are focused on the comparison between anatomical sections and ultrasonograms performed on the legs of nonlame horses. Ultrasonography was demonstrated to be a very accurate imaging procedure for soft tissue structures at the dorsal and abaxial aspects of the equine fetlock. Under clinical conditions, a thorough knowledge of normal ultrasonographic anatomy is critical for an accurate diagnosis of fetlock soft tissue injury.

Animals↗
PubMed1996

Segmental variations of in vitro mechanical properties in equine superficial digital flexor tendons.

OBJECTIVE: To determine the local variations of mechanical properties of the equine superficial digital flexor tendon (SDFT). SAMPLE POPULATION: 10 SDFT of adult horses, selected for absence of abnormality. PROCEDURE: Needles (with a dark marker at both ends) pinned perpendicularly through each tendon to delimit 7 segments. Each tendon was tested in traction until rupture; test was filmed, using an 8-mm video camera. For each image, the coordinates of the center of mass of each marker and the corresponding force were registered. The third-degree polynomial that best fits the stress-strain curve thus obtained was calculated by a least squares approximation. The modulus of elasticity (Emax) of each segment was evaluated as the maximum of the derivative of this polynomial. RESULTS: Mean rupture load of the 10 SDFT was 12,356 +/- 1,333 N. The strain at tendon rupture and Emax varied, respectively, from 8.1 +/- 1.3% and 1,002 +/- 161 MPa (sesamoidean region) to 12.5 +/- 1.7% and 1,189 +/- 63 MPa (metacarpal region). The values of the strain corresponding to Emax were remarkably similar along the SDFT (approx 5%). CONCLUSIONS: Emax appeared early homogeneous along an SDFT, although being slightly higher in the metacarpal region. The 5% strain corresponding to Emax could be the limit strain beyond which microlesions of the tendinous fibers begin to appear, this threshold being first reached during the traction test by the metacarpal segments.

Animals↗
PubMed1995

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.

Animals↗
PubMed1994

Functional anatomy of tendons and ligaments in the distal limbs (manus and pes).

Tendons and ligaments of the equine distal limbs have a prominent anatomic, functional, and clinical importance. This article reviews the descriptive and topographic anatomy of these structures in details. Special information is given about the mechanical properties and functional anatomy of the flexor tendons, accessory ligaments, and third interosseous muscle, as well as about their roles during the standing position and gaits.

Animals↗
PubMed1994

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 limitations of performance.

Animals↗
PubMed1983

[Comparative anatomy of the mandible. Functional aspects].

The structural morphology of the mandibula is presented and correlated to various types of mastication in several Mammalian species. The latter include: Carnivores (Dog, Cat, Cheetah, Lion); Omnivores (Man, Chimpanzee, Hog); Herbivores (Horse, Ox, Goat, Camel, Rabbit). While the mandibula is studied as a composite unit, a more analytical, segmental approach has been included, and both are illustrated by X-rays. The aspects presented underline the distribution as well as the local modifications of compact bone, and in addition, the arrangement and the development of spongy bone trabeculae. A preliminary classification with respect to structural elements has been suggested from two viewpoints: that of tension, the other of compression. Are also presented those variations linked to diet and alimentary intake, as well as their functional correlates.

Acinonyx↗
PubMedDate not supplied

Concrete use of the joint coordinate system for the quantification of articular rotations in the digital joints of the horse.

A method is detailed allowing the computation of three-dimensional (3D) joint angles. Each joint of the equine digit is modelled as a sequence of three single axis rotary joints. The Joint Coordinate System was used; it involves a specific sequence of cardanic angles. The decomposition of the angles was chosen so that the three elementary angles coincide with the flexion/extension, passive abduction/adduction and lateral/medial rotations. The algorithms and kinematic procedures were described for the equine front digital joints. This method was tested in vitro on four forelimbs. For each limb, angle values were measured while the member was loaded by a press (from 500 to 6000 N). These tests were repeated while a wedge raised one part of the hoof (toe, heel, lateral and medial sides) in order to induce modifications of the angular patterns of the joints. This method allowed a precise quantitative determination of 3D joint movements. The modifications occurring with the wedges are clearly identified and confirm some previously published semi-quantitative observations. Moreover, this method provides a way to collect objective data on the functional anatomy of joints and could be used to study connective shoeing thoroughly. It may be directly applied to other species and may be used by researchers interested in discreet articular movements, especially occurring in other planes than the sagittal one.

Anatomy, Veterinary↗