Trapezius The trapezius has its origins at the base of the occipital bone of

Trapezius the trapezius has its origins at the base

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Trapezius - The trapezius has its origins at the base of the occipital bone of the cranium and on the spines of C7 to T12 of the upper vertebral column. Muscles of the Trunk The muscles of the chest include the intercostal muscles and the diaphragm. These muscles are primarily responsible for breathing. The intercostal muscles are located between the ribs. They have their origin and insertion on the ribs and are responsible for raising and lowering the rib cage during breathing. Muscles That Form the Abdominal Wall Contraction of the abdominal muscles performs other functions. It causes flexion and rotation of the vertebral column and compression of
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the abdominal organs during urination, defecation, and childbirth. The four abdominal muscles are as follows: Rectus abdominis. As the name implies, the fibers of the rectus abdominis run in an up and down, or longitudinal, direction. They extend from the sternum to the pubic bone. Contraction of this muscle flexes the vertebral column. External oblique. Abdominal muscles called the external oblique muscles make up the lateral walls of the abdomen. The fibers run obliquely (slanted). Internal oblique. The internal oblique muscles are part of the lateral walls of the abdomen. They add to the strength provided by the external oblique muscles; the fibers of the internal and external oblique muscles form a crisscross pattern. Transversus abdominis. The transversus abdominis muscles form the innermost layer of the abdominal muscles. The fibers run horizontally across the abdomen. To remember the abdominal muscles, think of that spare TIRE: T transversus abdominis I internal oblique R rectus abdominis E external oblique The aponeuroses of the abdominal muscles on opposite sides of the midline of the abdomen form a white line called the linea alba. Muscles that move the vertebral column the movements include flexion, extension, hyperextension, lateral flexion, and rotation of the vertebral column. Muscles that move the vertebral column include the erector spinae, sternocleidomastoid, trapezius, abdominal muscles, and iliopsoas. Deep to the trapezius and the latissimus dorsi is the erector spinae; it extends the length of the vertebral column, from the sacrum to the cranium. As the erector spinae muscle ascends, it forms three columns of muscles. The erector spinae muscle causes extension and lateral flexion of the vertebral column and rotation of the head. This muscle assists in the maintenance of an erect posture. Contraction of both sternocleidomastoid muscles causes flexion of the head at the neck, whereas contraction of one muscle rotates the head in the opposite direction (causes rotation of the cervical vertebral column). The trapezius maintains the vertebral column in extension. The abdominal muscles cause flexion and rotation of the vertebral column, and the iliopsoas flexes the vertebral column at the hip.
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  • Fall '19
  • muscle weakness, muscle atrophy, functions of muscles

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