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Central nervous system
Published in A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha, Clark’s Procedures in Diagnostic Imaging: A System-Based Approach, 2020
A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha
Sagittal imaging is performed initially to demonstrate the long axis of the spinal canal, the anatomy and relationships of the vertebral bodies and posterior spinal elements, intervertebral discs, spinal cord and thoracic nerve roots. Abnormalities of the bone marrow, intervertebral discs, spinal nerves and spinal cord are demonstrated. On T2- and T1-weighted imaging the bone marrow within the vertebral bodies is high signal due to the adipose tissue content. The nucleus pulposus of healthy intervertebral discs is hydrated and high signal on T2-weighted imaging surrounded by the low signal nucleus fibrosis. CSF is high signal in contrast to the low-intermediate signal of the spinal cord and spinal nerves.
Fundamentals
Published in Clare E. Milner, Functional Anatomy for Sport and Exercise, 2019
There are three cardinal planes and three axes about which joint movement can occur. A plane is two-dimensional, like a page in a book or an image on a television screen. The only movement that can be clearly seen in a plane is one in which the body segments move within that plane. That is, they do not move towards or away from the plane, but within its two-dimensional space. In the following examples, assume that the person is standing in the anatomical position. The sagittal plane is the one seen when looking from the side (Figure 3). If you look at a person from the side, you can clearly see the movement of flexing and extending the knee. Knee flexion and extension occur in the sagittal plane. The angle between the leg and thigh can be seen increasing and decreasing as the knee extends and flexes. However, abduction and adduction of the hip cannot be clearly seen in the sagittal plane. The changing angle between the thigh and pelvis cannot be seen from the sagittal, or side, view. Hip abduction and adduction can be clearly seen if you look at the person from the front; this is the frontal, or coronal, plane. In addition to the sagittal and frontal planes, there is a horizontal plane, the transverse plane, which is seen when looking down on a person from above. Internal and external rotation movements of the body segments can be seen in this plane, such as internal and external rotation of the hip.
Pedicle Subtraction Osteotomy for the Treatment of Fixed Sagittal Imbalance *
Published in Alexander R. Vaccaro, Charles G. Fisher, Jefferson R. Wilson, 50 Landmark Papers, 2018
Markian A. Pahuta, Stephen J. Lewis
In this study, Bridwell and colleagues included only patients with sagittal imbalance (deviation in SVA). However, patients with sagittal balance with sagittal malalignment (deviation in PT and/or PI-LL) may also benefit from sagittal deformity correction. Sagittal balance refers to whether the center of mass is centered over the pelvis and feet.6Sagittal alignment refers to whether the angular configuration of the spine permits standing with maximal muscular efficiency.6 Even in the presence of malalignment, it is possible for the spine to be balanced due to compensatory mechanisms. Schwab and colleagues measured spinopelvic parameters in 429 adult patients with spinal deformity and determined threshold values for severe disability: PT ≥22°, SVA ≥ + 47 mm, and/or PI-LLT12:S1 ≥ + 11°.2 These threshold values provide a framework in planning the appropriate correction for the deformity.
Summarizing the medieval anatomy of the head and brain in a single image: Magnus Hundt (1501) and Johann Dryander (1537) as transitional pre-Vesalian anatomists
Published in Journal of the History of the Neurosciences, 2022
The “skull” band (or layer) in the figure (labeled E) has several wavy lines, which represent cranial sutures, but drawn as if viewed from above rather than from a three-quarter view, as the rest of the figure is; consequently, the sagittal suture appears to run over the left frontoparietal area near the superior temporal line (i.e., the apex of the temporalis muscle insertion), rather than along the midline of the skull from the bregma. Moving from left to right, within the skull band, the sutures represented are (with symbols from the bottom of the left-side legend): Y. Coronalis (Coronal; note the Gothic “Y” is rotated 90 degrees to the left), Z. Sagittal (note the Gothic Z in the figure is a minuscule letter rotated 90 degrees to the left, whereas in the legend the letter is a majuscule) and +. Lauda (sic, Lambdoid).
Customized k-nearest neighbourhood analysis in the management of adolescent idiopathic scoliosis using 3D markerless asymmetry analysis
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2019
Maliheh Ghaneei, Ronald Ekyalimpa, Lindsey Westover, Eric C. Parent, Samer Adeeb
The cosmetic deformity associated with AIS involves torso asymmetry. A person with no spinal curvature is approximately symmetric across the midsagittal plane, which means that the person’s torso and its reflection along this plane are almost perfectly aligned (Ho et al. 2015). However, for a person with an asymmetric torso, the sagittal plane is no longer a plane of symmetry. Our method takes advantage of the best plane of symmetry identification method introduced by Hill et al. (2014) to assess the deformity of the scoliotic spine. The best plane of symmetry is roughly aligned with the midsagittal plane; however, the actual plane is determined by minimizing the sum of distances between the patient’s torso and its bilateral reflection (Komeili et al. 2014). The asymmetry is then illustrated using a deviation contour map plotted on the patient’s torso. The effects of the spinal curvature are visualized in terms of dense colour areas called deviation patches containing many points whose colours represent the distance between the original and reflected torsos, depicting both areas of protrusion or depression relative to the other side (Komeili et al. 2014). The maximum and root mean square of these deviations are computed as asymmetry parameters (MaxDev and RMS, respectively). These asymmetry parameters have been compared with the Cobb angle measured in the corresponding region of the torso to create decision trees predicting curve severity on a given test day and progression between consecutive examinations (Komeili et al. 2014, 2015b; Ghaneei et al. 2018).
Three-dimensional analysis of acetabular orientation using a semi-automated algorithm
Published in Computer Assisted Surgery, 2019
Changhwan Lee, Jongseong Jang, Hyung Wook Kim, Young Soo Kim, Yeesuk Kim
In the first phase, we used an iterative method to determine the pelvic coordinate system according to the method of Lee et al. [8] (Figure 1). This method is useful for measuring the anterior pelvic plane (APP), as it has favorable intra-observer reliability (ICCs =1), and the results from this method are similar to those determined by an experienced surgeon (ICCs ≥0.937). The APP was defined as the tangential plane of the pelvis determined by four pelvic landmarks: the right and left anterior superior iliac spines and the right and left pubic tubercles. Four ROI boxes for each landmark were defined manually by the user in 3-D space. After that, the landmarks were determined by an iterative compensation algorithm of the pelvic pose. The algorithm proceeded by decreasing the difference in angle between the estimated APP of the current iteration and that of the previous iteration. The iteration was stopped when the angle was less than one degree (<1°). Each landmark from the last iteration was the most ventral point with respect to the patient and was defined as the true landmark, and the APP was estimated using the least square method [9]. The sagittal plane was generated by the line connecting the two midpoints of the bilateral anatomical landmarks and the normal vector of the APP. The axial plane was perpendicular to both coronal and sagittal planes.