Distal Limb (distal + limb)

Distribution by Scientific Domains

Selected Abstracts

Amputation of the equine distal limb: indications, techniques and long-term care

T. P. Vlahos
First page of article [source]

Use of a 3D dynamometric horseshoe to assess the effects of an all-weather waxed track and a crushed sand track at high speed trot: Preliminary study

D. Robin
Summary Reasons for performing study: Track surface quality is considered a risk factor of musculoskeletal injuries. Ground reaction force (GRF) measurement is a relevant approach to study the interaction between the hoof and the ground. Force plates are not adapted to compare different surfaces at high speed. A 3D dynamometric horseshoe (DHS), using 4 triaxial piezoelectric sensors, has been developed and validated. Objectives: To use the DHS to compare the effects of 2 track surfaces, an all-weather waxed track and a crushed sand track, on the GRF in trotter horses under training conditions. Methods: The right forelimb of 3 French Trotters was equipped with the DHS. Two tracks were tested in a straight line: a crushed sand track (S) and an all-weather waxed track (W). For each session, trials were repeated 3 times in a Latin square design. The speed of the runs was set at 10 m/s and recorded synchronously. For each trial, data acquisition was performed at 600 Hz and 10 consecutive strides were analysed. Statistical differences were tested using a general linear model procedure. Results: The amplitude of the maximal longitudinal braking force (Fx) was significantly lower on W compared to S. This event happened about 6% later in the stance phase on W. The magnitude of the GRF at impact decreased on W. The average speed and the mean stance phase duration were not statistically different on both surfaces. The stride length was about 6 cm longer on S. Conclusion and potential relevance: This study demonstrates the ability and sensitivity of the DHS to discriminate track surfaces by measuring the GRF at high speed. These preliminary results show that the loading rate, the amplitude of horizontal braking and shock at impact are attenuated on W, which suggests a reduction of stresses in the distal limb. [source]

Superficial digital flexor tendon lesions in racehorses as a sequela to muscle fatigue: A preliminary study

M. T. Butcher
Summary Reasons for performing study: Racing and training related lesions of the forelimb superficial digital flexor tendon are a common career ending injury to racehorses but aetiology and/or predisposing causes of the injury are not completely understood. Objectives: Although the injury takes place within the tendon, the lesion must be considered within the context of the function of the complete suspensory system of the distal limb, including the associated muscles. Methods: Both muscle and tendon function were investigated in vivo using implanted strain gauges in 3 Thoroughbred horses walking, trotting and cantering on a motorised treadmill. These data were combined with assessments of muscle architecture and fibre composition to arrive at an overview of the contribution of each muscle-tendon unit during locomotion. Results: The superficial digital flexor muscle has fatigue-resistant and high force production properties that allow its tendon to store and return elastic energy, predominantly at the trot. As running speed increases, deep digital flexor tendon force increases and it stabilises hyperextension of the fetlock, thus reinforcing the superficial digital flexor in limb load support. The deep digital flexor muscle has fast contracting properties that render it susceptible to fatigue. Conclusion: Based on these measurements and supporting evidence from the literature, it is proposed that overloading of the superficial digital flexor tendon results from fatigue of the synergistic, faster contracting deep digital flexor muscle. Potential relevance: Future research investigating distal limb system function as a whole should help refine clinical diagnostic procedures and exercise training approaches that will lead to more effective prevention and treatment of digital flexor tendon injuries in equine athletes. [source]

Developmental aspects of distal limb conformation in the horse: the potential consequences of uneven feet in foals

Summary Reasons for performing study: Distal limb conformation is generally accepted to be an important item with respect to performance and soundness in mature horses, but little is known about the developmental aspects. Objectives: To gain insight into the development of distal limb conformation and to assess the possible consequences of uneven feet in foals. Methods: Conformation of the distal front limbs of 23 Warmblood foals was scored visually and measured using radiographs, at ages 27 and 55 weeks. At the same ages, pressure measurements were made under both front feet. Results: At both ages the hoof-pastern axis was broken-backwards on radiographs, but only occasionally recognised as such, when scored by eye. Over time, the hoof angle decreased, while both the angles of the dorsal and solar surfaces of the distal phalanx (P3) increased and the parallelism between hoof wall and P3 improved. The foals with uneven feet at age 27 weeks showed a significant difference in distal limb loading that persisted until age 55 weeks. Conclusions: The alignment of the distal limb in the sagittal plane increased in a 6 month period. Visual assessment was not sensitive enough to appreciate this. The growth processes in the distal limb could not compensate for existing unevenness and ensuing asymmetrical limb loading. Potential relevance: Foals have a different conformation of the distal limb from mature horses, which should be taken into account when interpreting radiographs. Unevenness of the feet resulted in asymmetrical loading of the proximal and distal interphalangeal joint, which might lead to increased susceptibility to overload injuries and decreased performance at mature age. [source]

Shoeing sound Warmblood horses with a rolled toe optimises hoof-unrollment and lowers peak loading during breakover

M. C. V. van Heel
Summary Reasons for performing study: Overload injuries in sport horses commonly occur; shoeing techniques are believed to be important in prevention of these injuries, but there is a paucity of scientific information identifying the potential connection. Objectives: To test a horseshoe with a modified rolled toe designed to ease the process of breakover and decrease loading of lesion-prone structures of the distal limb. Methods: Twenty clinically sound Warmblood horses trotted over a track containing a pressure/force measuring system and 6 infrared cameras. The horses were measured with 2 types of shoes, standard flat shoes and shoes with a rolled toe. The shoeing procedure was randomised and horses had 2 days between measurements to adapt to the shoes. Results: Limb placement and timing characteristics, e.g. breakover duration, did not change significantly. There was an improvement in the ease of movement to roll over the toe in the shoes with a rolled toe, due mainly to a smoother hoof-unrollment pattern. The peak indicative moment decreased substantially at the onset of breakover in the shoe with the rolled toe. Conclusions: With a rolled toe the process of hoof-unrollment is smoother, which improves the coordination of this process, and lowers peak loading of the distal limb during breakover. Potential relevance: This study stresses the importance of proper shoeing in sound horses, showing that shoe modifications can optimise the loading characteristics of the distal limb and therefore might be a means to prevent sport horses from overload injuries. [source]

Longitudinal development of equine conformation from weanling to age 3 years in the Thoroughbred

Summary Reasons for performing study: There is little information available to define conformational changes with age using an objective but practical method of recording specific body measurements. Objective: To analyse conformation objectively in a population of racing Thoroughbreds and describe the changes from weanling to age 3 years. Methods: Annual photographs were taken over 4 years and conformation measurements made from photographs using specific reference points marked on the horses. Results: Correlation analysis revealed highly significant, moderate to strong relationships between long bone lengths and wither height for all ages. All long bone lengths showed moderate to strong relationships with each other for all ages. The front and rear pastern angles were significantly correlated with the angle of the dorsal surface of the front and rear hooves, respectively, for all. Wither height, croup height and length of neck topline, neck bottomline, scapula, humerus, radius and femur increased significantly from age 0,1 year and age 1,2 years. Hoof lengths (medial and lateral, right and left) grew significantly between the ages of 0 and 1 and 1 and 2 years, but decreased in length between age 2 and 3 years. Horses became more offset in the right limb between weanling and age 3 years, but the offset ratios did not change with age on the left limb. The angle of the scapula (I), shoulder and radiometacarpus significantly increased between all age groups (became more upright). The angle of the dorsal surface of the hooves (both front and hind) decreased significantly from ages 0 to 1 and 1 to 2 years, but showed no significant difference between ages 2 and 3 years. Conclusions: A strong relationship between long bone lengths and wither height for all ages supports the theory that horses are proportional. Longitudinal bone growth in the distal limb increased only 5,7% from weanling to age 3 years and is presumably completed prior to the yearling year. Several growth measures increased from ages 0 to 1 and 1 to 2 years, but did not increase from age 2,3 years; indicating that growth rate either showed or reached a plateau at this time. Potential relevance: This study provides objective information regarding conformation and skeletal growth in the Thoroughbred which can be utilised for selection and recognition of significant conformational abnormalities. [source]

Early Distal-less expression in a developing crustacean limb bud becomes restricted to setal-forming cells

Terri A. Williams
SUMMARY Distal-less (Dll) plays a well-known role in patterning the distal limb in arthropods. However, in some taxa, its expression even during early limb development is not always limited to the distal limb. Here, I trace the expression of Distal-less in a crustacean (Thamnocephalus platyurus) from the early limb bud to later stages of limb development, a period that includes differentiation of juvenile and adult morphology. During early development, I find two distinct types of DLL expression: one correlated with proximal distal leg patterning and the other restricted to setal-forming cells. Later in development, all the DLL expression is restricted to setal-forming cells. Based on the particular cells expressing DLL, I hypothesize an ancestral role for Dll function in the formation accessory cells of sensilla. [source]

A Simple Technique of Distal Limb Perfusion During Prolonged Femoro-Femoral Cannulation

Navid Madershahian M.D.
A serious complication of prolonged femoral cannulation remains the ischemic injury of the distal limb. Subjects: To minimize the incidence of ischemia in the cannulated leg, we have begun to provide antegrade femoral blood flow by placing a vascular introducer percutaneously distal to the arterial cannula into the superficial femoral artery and connecting it to the side port of the arterial line. Conclusion: This technique of distal limb perfusion was found to be safe and effective in preventing lower limb ischemia for patients with prolonged femoral cannulation for extracorporeal circulatory support. [source]

Cryptococcosis in ferrets: a diverse spectrum of clinical disease

Cryptococcosis was diagnosed in seven ferrets (five from Australia; two from western Canada) displaying a wide range of clinical signs. Two of the ferrets lived together. One (5-years-old) had cryptococcal rhinitis and presented when the infection spread to the nasal bridge. Its sibling developed cryptococcal abscessation of the right retropharyngeal lymph node 12 months later, soon after developing a severe skin condition. DNA fingerprinting and microsatellite analysis demonstrated that the two strains isolated from these siblings were indistinguishable. Two ferrets (2- to 3-years-old) developed generalised cryptococcosis: one had primary lower respiratory tract disease with pneumonia, pleurisy and medi-astinal lymph node involvement, while in the other a segment of intestine was the primary focus of infection with subsequent spread to mesenteric lymph nodes, liver and lung. The remaining three ferrets (1.75 to 4-years-old) had localised disease of a distal limb, in one case with spread to the regional lymph node. Cryptococcus bacillisporus(formerly C neoformansvar gattii) accounted for three of the four infections in Australian ferrets where the biotype could be determined. The Australian ferret with intestinal involvement and the two ferrets from Vancouver had C neoformansvar grubiiinfections. [source]