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Anatomy of the Pelvis
Published in Gowri Dorairajan, Management of Normal and High Risk Labour During Childbirth, 2022
Properties that characterise the female pelvis maximise the dimensions of the birth canal. Therefore, broadening of the true pelvis sets the acetabulum further apart, increasing the lever arm of body weight on the hips. To some extent, elongation of the femoral neck can compensate for this, lowering the required abdominal work in gait. This femoral neck length is associated with fracture risk [9]. An alternative mechanism for retaining bipedal gait is to place the acetabulum deeper in the Pelvis- Coxa Profunda. Hence the femoral head is rounded in coxa profunda with a good head–neck offset. The femoral neck affects the acetabular rim and labrum when the hip is extended and laterally rotated or flexed and medially rotated [10]. This acetabular rim and labrum damage may result in osteoarthritis usually seen in females in their late 50s and 60s [8].
Echocardiographic Features of Hypertrophic Cardiomyopathy
Published in Srilakshmi M. Adhyapak, V. Rao Parachuri, Hypertrophic Cardiomyopathy, 2020
The AML is elongated in most HCM patients (it is less than 30 mm in healthy subjects) and is even more pronounced in patients with LVOTO with an average length of 34–35 mm (measurement includes the aorto-mitral area), with the coapted leaflets having an average extension of 24 mm below the level of the mitral annulus during systole [21]. Frequently the tip of the AML beyond the coaptation point curves into the left ventricular outflow tract (LVOT) and this small length of the leaflet is influenced by the bloodstream rather than the chamber pressures and leans towards or touches the IVS causing LVOTO. Corrective surgical procedures of the mitral leaflets are based on these mechanics and the abnormal measurements obtained during imaging. Isolated PML elongation (the length is less than 15–17 mm in healthy subjects) is infrequently seen, but when present can contribute to LVOTO. The cause of the elongation of leaflets has been attributed to a primary phenotypic manifestation and not due to any secondary stretch factors of an anteriorly displaced MV. It is important to note that elongation of leaflets is not due to any myxomatous changes, but are elongated cell lines originating from the coelomic mesothelium (though concomitant myxomatous disease has also been reported in some patients, which may add to the complexity of the disease).
Mechanical Testing of Ligaments and Tendons
Published in Yuehuei H. An, Richard J. Friedman, Animal Models in Orthopaedic Research, 2020
Savio L-Y. Woo, Theodore T. Manson, Tracy M. Vogrin
In order to effectively measure the strain present in soft tissues during a uniaxial tensile test, accurate measurements of the initial length of the specimen and the elongation at any point during the test must be made. Many different methodologies have been used to measure this elongation.6,12-17 Literature use of percent elongation based on the clamp to clamp distance involved contributions of not only the ligament itself, but also its insertions. To measure the strain in the tissue, however, measurement of the strain in the ligament substance must be made. The technology available to measure tissue strain can again be divided into contact and non-contact designs.
Structural and haemodynamic properties of ocular vasculature in axial myopia
Published in Clinical and Experimental Optometry, 2022
Mei Zhao, Andrew KC Lam, Allen MY Cheong
Oxygen saturation of retinal vessels can be estimated by comparing the light absorption of oxygenised and deoxygenated haemoglobin. A decreased arterial saturation and an unchanged venous saturation with increasing axial length have been commonly reported in previous studies,88,94,95 while the alteration of oxygen consumption (i.e. difference between arterial and venous saturation) remains uncertain. Zheng et al.88 found lower oxygen consumption in highly myopic eyes, while Heitmar94 and Lim et al.95 reported that it was not affected by axial elongation. Decrease oxygen saturation does not necessarily mean reduced blood supply. It may be caused by increased oxygen transportation between central retinal vessels or be just an uncorrected measurement error.88
Previous foot injuries associated with a greater likelihood of Achilles tendon ruptures in professional American football players
Published in The Physician and Sportsmedicine, 2018
Michael K. Krill, Joshua Hoffman, JaeWon Yang, Johnathan D. Hodax, Brett D. Owens, Timothy E. Hewett
As reported by Mai et al., the RTP rate after AT ruptures for NFL athletes is extremely low (72.5%) compared to other orthopedic procedures in the NFL [17]. In addition, the athletes that do return experience significant reductions in statistical performance and power production in the repaired AT [17]. One possible reason for a decreased risk of re-ruptures may be that athletes who are most likely to re-rupture their AT never return to competitive football or pristine fitness levels as only those athletes who achieve an adequate recovery are able to return to competitive sport [5,6,14,15,17]. Further evaluation of NFL athletes who sustained an AT rupture and never returned to competitive football or training may improve our understanding what leads to a successful AT reconstruction as currently AT ruptures produce one of the lowest RTP rates of orthopedic procedures. A study by Orishimo et al. identified that even after successful AT repairs, some degree of AT elongation remains regardless of technique [38]. Elongation and slack in the repaired AT is a potential contributor to decreased power production and may also reduce tension, thus prevent the elite athlete from sustaining the acute force necessary to re-rupture the AT [38]. Eleven athletes sustained bilateral AT ruptures over the 8 years of our study. Understanding the biomechanics, past medical, orthopedic, and family history may help identify factors that predispose specific athletes to AT ruptures.
Antero posterior elongation of midbrain in traumatic brain injury- significant sign yet a mistaken entity
Published in British Journal of Neurosurgery, 2018
Raghunath Avanali, Biju Bhadran, Sunil Panchal, Krishna Kumar P., Abhishek V., Kshitij Gulhane, Harison G.
The study was conducted to seek answers to a few questions which the authors have been asking themselves regarding the CT-scan appearance of the brainstem in certain cases of traumatic brain injury (TBI) with cerebral herniation and brainstem distortion. In our experience, the finding of anteroposterior elongation of the midbrain was observed to have a very poor prognosis, although this was not always the case. An in-depth review is lacking in the literature and was in fact quoted in only a few articles.1–4 We had the three following concepts in mind when the study was designed: (1) Documentation of the anteroposterior elongation of the midbrain, if any; (2) how to measure the magnitude of elongation above which the elongation can be obviously detected and diagnosed visually; and (3) to evaluate how significantly it influenced the outcome.