This diagnostic image demonstrates the segmentation of the psoas major muscle using unenhanced abdominal computed tomography (CT) at the level of the third lumbar vertebra (L3). Image A presents a transverse (axial) view showing the cross-sectional area of the bilateral psoas muscles highlighted in green. The muscles are situated posterolaterally to the centrally located vertebral body and anterior to the transverse processes. Visible surrounding anatomy includes the spinal canal, abdominal wall, and intra-abdominal viscera. Image B shows a coronal reconstruction of the same region, with the green-shaded regions indicating the vertical orientation of the psoas muscle segments adjacent to the L3 vertebral body. The lumbar spine is centrally aligned, with the kidneys visible laterally in the retroperitoneal space. This visualization is characteristic of sarcopenia or osteoporosis research, where psoas muscle mass and radiomic features are analyzed as biomarkers for musculoskeletal health and systemic frailty.

This diagnostic image is a 3D volume-rendered reconstruction derived from a CT scan, illustrating the musculoskeletal anatomy of the posterior abdominal wall and pelvis. The primary educational focus is the psoas major muscle, which is digitally segmented and highlighted in orange on the right side of the anatomical model (patient's left). The skeletal framework displays the lower rib cage, the lumbar vertebral column (L1-L5), the complete bony pelvis (including ilium, ischium, and pubis), and the proximal femurs. The psoas major is shown originating from the lateral aspects of the T12 and lumbar vertebrae, coursing inferiorly and laterally over the pelvic brim and anterior to the sacroiliac joint. It terminates at its insertion point on the lesser trochanter of the proximal femur. This visual is used in clinical research to demonstrate the measurement of Psoas Muscle Volume (PMV) and Psoas Muscle Index (PMI), which serve as radiological markers for sarcopenia and are prognostic indicators in oncological outcomes. The rendering clearly depicts the spatial relationship between the axial skeleton and the major hip flexor musculature.

This musculoskeletal diagram features a 3D anatomical model of the human skeleton from an anterior view, illustrating the biomechanics of the psoas muscles during gait. The model is shown in mid-stride: the left leg is in the stance phase (straight and planted), while the right leg is in the swing phase (flexed at the hip and knee with dorsiflexion of the foot). The psoas major muscles are represented by bilateral red vector lines. Each muscle path is defined by three blue markers: the origin at the transverse processes of the lumbar spine (L5 region), a mid-path 'via point' at the pelvic brim (iliopectineal eminence), and the insertion at the lesser trochanter of the femur. This visualization highlights the dynamic changes in muscle length and the relationship between the lumbar spine, pelvis, and femur during locomotion. The image is designed for orthopedic and physical therapy education, specifically focusing on kinesiology, muscle modeling, and the functional anatomy of the hip flexors.