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Maximal Flexion (maximal + flexion)

Distribution by Scientific Domains

Life Sciences	50%

Selected Abstracts

The effect of rising and sitting trot on back movements and head-neck position of the horse

EQUINE VETERINARY JOURNAL, Issue 5 2009
P. de COCQ
Summary Reason for performing study: During trot, the rider can either rise from the saddle during every stride or remain seated. Rising trot is used frequently because it is widely assumed that it decreases the loading of the equine back. This has, however, not been demonstrated in an objective study. Objective: To determine the effects of rising and sitting trot on the movements of the horse. Hypothesis: Sitting trot has more extending effect on the horse's back than rising trot and also results in a higher head and neck position. Methods: Twelve horses and one rider were used. Kinematic data were captured at trot during over ground locomotion under 3 conditions: unloaded, rising trot and sitting trot. Back movements were calculated using a previously described method with a correction for trunk position. Head-neck position was expressed as extension and flexion of C1, C3 and C6, and vertical displacement of C1 and the bit. Results: Sitting trot had an overall extending effect on the back of horses when compared to the unloaded situation. In rising trot: the maximal flexion of the back was similar to the unloaded situation, while the maximal extension was similar to sitting trot; lateral bending of the back was larger than during the unloaded situation and sitting trot; and the horses held their heads lower than in the other conditions. The angle of C6 was more flexed in rising than in sitting trot. Conclusions and clinical relevance: The back movement during rising trot showed characteristics of both sitting trot and the unloaded condition. As the same maximal extension of the back is reached during rising and sitting trot, there is no reason to believe that rising trot was less challenging for the back. [source]

Effects of 6° elevation of the heels on 3D kinematics of the distal portion of the forelimb in the walking horse

EQUINE VETERINARY JOURNAL, Issue 8 2004
H. CHATEAU
Summary Reasons for performing study: Understanding of the biomechanical effects of heel elevation remains incomplete because in vivo studies performed with skin markers do not measure the actual movements of the 3 digital joints. Objective: To quantify the effects of 6° heel wedge on the 3-dimensional movements of the 4 distal segments of the forelimb in the walking horse. Methods: Four healthy horses were used. Kinematics of the distal segments was measured invasively with a system based on ultrasonic triangulation. Three-dimensional rotations of the digital joints were calculated by use of a ,joint coordinate system' (JCS). Data obtained with heel wedges were compared to those obtained with standard shoes during the stance phase of the stride. Results: Heel wedges significantly increased maximal flexion of the proximal (PIPJ) and distal (DIPJ) interphalangeal joints and maximal extension (mean ± s.d. +0.8 ± 0.3°) of the metacarpophalangeal joint (MPJ). Extension of the PIPJ and DIPJ was decreased at heel-off. Few effects were observed in extrasagittal planes of movement. Conclusions: Heel wedges affect the sagittal plane kinematics of the 3 digital joints. Potential relevance: Controversial effects previously observed on the MPJ may be explained by the substantial involvement of the PIPJ, which was wrongly neglected in previous studies performed on the moving horse. [source]

Kinematics of the knee at high flexion angles: An in vitro investigation

JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 1 2004
Guoan Li
Abstract Restoration of knee function after total knee, meniscus, or cruciate ligament surgery requires an understanding of knee behavior throughout the entire range of knee motion. However, little data are available regarding knee kinematics and kinetics at flexion angles greater than 120° (high flexion). In this study, 13° cadaveric human knee specimens were tested using an in vitro robotic experimental setup. Tibial anteroposterior translation and internal,external rotation were measured along the passive path and under simulated muscle loading from full extension to 150° of flexion. Anterior tibial translation was observed in the unloaded passive path throughout, with a peak of 31.2 ± 13.2 mm at 150°. Internal tibial rotation increased with flexion to 150° on the passive path to a maximum of 11.1 ± 6.7°. The simulated muscle loads affected tibial translation and rotation between full extension and 120° of knee flexion. Interestingly, at high flexion, the application of muscle loads had little effect on tibial translation and rotation when compared to values at 120°. The kinematic behavior of the knee at 150° was markedly different from that measured at other flexion angles. Muscle loads appear to play a minimal role in influencing tibial translation and rotation at maximal flexion. The results imply that the knee is highly constrained at high flexion, which could be due in part to compression of the posterior soft tissues (posterior capsule, menisci, muscle, fat, and skin) between the tibia and the femur. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved. [source]

The ligamentum olecrani of the Elbow Joint in Dogs and Cats

ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2005
E. Engelke
The olecranon ligament (ligamentum olecrani) is described as an elastic ligament of the elbow joint in carnivores that tenses the caudomedial part of the joint capsule. The aim of the study was to compare the course and the microscopic structure of the ligament in dogs and cats. The elbow regions of 25 dogs and 15 cats were dissected to examine the topography of the ligament in extension and flexion. Furthermore, the olecranon ligaments of five dogs and five cats were studied using routine histological methods. Additional sections were stained with Resorcin,Fuchsin and Orcein to detect elastic fibres. In both species the olecranon ligament originates at the lateral surface of the epicondylus medialis humeri and inserts at the cranial crest of the olecranon extending distally to the roof of the processus anconeus. Tension of the ligament only occurs when the elbow joint is flexed maximally. This tension is increased by a slight supination of the forearm, which takes place automatically in this joint position. In dogs the ligament is long (30,40 mm in medium sized breeds) and relatively slim (approx. 2,4 mm). In cats the ligament is short (10,12 mm) and relatively strong (5,8 mm). The histological examination of the olecranon ligament shows all signs of a tight collagenous ligament with a negligible amount of elastic fibres. The olecranon ligament helps to limit the maximal flexion of the elbow joint. In addition, it controls a slight lateral movement of the processus anconeus during the automatic supination of the antebrachial bones in extreme flexion of the elbow joint. [source]