VertebraEach vertebra (pl.: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spinal segment and the particular species. The basic configuration of a vertebra varies; the vertebral body (also centrum) is of bone and bears the load of the vertebral column.
SacrumThe sacrum (pl.: sacra or sacrums), in human anatomy, is a triangular bone at the base of the spine that forms by the fusing of the sacral vertebrae (S1–S5) between ages 18 and 30. The sacrum situates at the upper, back part of the pelvic cavity, between the two wings of the pelvis. It forms joints with four other bones. The two projections at the sides of the sacrum are called the alae (wings), and articulate with the ilium at the L-shaped sacroiliac joints.
Abdominal external oblique muscleThe abdominal external oblique muscle (also external oblique muscle or exterior oblique or musculus obliquus abdominis externus) is the largest and outermost of the three flat abdominal muscles of the lateral anterior abdomen. StructureThe external oblique is situated on the lateral and anterior parts of the abdomen. It is broad, thin, and irregularly quadrilateral, its muscular portion occupying the side, its aponeurosis the anterior wall of the abdomen.
Abdominal internal oblique muscleThe internal abdominal oblique muscle, also internal oblique muscle or interior oblique or musculus obliquus abdominis internus, is an abdominal muscle in the abdominal wall that lies below the external abdominal oblique muscle and just above the transversus abdominis muscle.
Erector spinae musclesThe erector spinae ( ) or spinal erectors is a set of muscles that straighten and rotate the back. The spinal erectors work together with the glutes (gluteus maximus, gluteus medius and gluteus minimus) to maintain stable posture standing or sitting.
Axis (anatomy)In anatomy, the axis (from Latin axis, "axle") is the second cervical vertebra (C2) of the spine, immediately inferior to the atlas, upon which the head rests. The spinal cord passes through the axis. The defining feature of the axis is its strong bony protrusion known as the dens, which rises from the superior aspect of the bone. StructureThe body is deeper in front or in the back and is prolonged downward anteriorly to overlap the upper and front part of the third vertebra.
TransversospinalesThe transversospinales are a group of muscles of the human back. Their combined action is rotation and extension of the vertebral column. These muscles are small and have a poor mechanical advantage for contributing to motion. They include: the three semispinalis muscles, the multifidus muscle, and the rotatores spinae muscles.
Muscle fascicleA muscle fascicle is a bundle of skeletal muscle fibers surrounded by perimysium, a type of connective tissue. StructureMuscle cells are grouped into muscle fascicles by enveloping perimysiumconnective tissue. Fascicles are bundled together by epimysium connective tissue. Muscle fascicles typically only contain one type of muscle cell (either type I fibres or type II fibres), but can contain a mixture of both types.
Transverse abdominal muscleThe transverse abdominal muscle (TVA), also known as the transverse abdominis, transversalis muscle and transversus abdominis muscle, is a muscle layer of the anterior and lateral (front and side) abdominal wall, deep to (layered below) the internal oblique muscle. It serves to compress and retain the contents of the abdomen as well as assist in exhalation.*As an Amazon Associate I earn from qualifying purchases.