Trunk movement patterns

Each lab group needs:
  1. Using the skeletons and your anatomy resources, focus on a lumbar intervertebral joint and identify these structures:
    • Vertebral body
    • Vertebral arch
      • Pedicle
      • Lamina
    • Spinal canal
    • Vertebral processes
      • Spinous process
      • Transverse process
      • Superior and inferior articulating processes
    • Facet (zygapophyseal) joint

  2. The course's objectives specify that students obtain specific knowledge concerning the trunk's anterior and posterior muscles. For this lab exercise, consider the muscles or muscle groups listed below. For each, select a representative group of fibers and mark the approximate locations of their attachments with a skin pencil. You may delay drawing lines of application for the moment. The parenthetical references are to pages in Kendall, McCreary, and Provance (1993) that contain precise anatomical information.

    • Anterior muscles
      • right or left rectus abdominis (147)
      • right or left external oblique (148)
      • right or left internal oblique (149)

    • Posterior muscles (139)
      • right or left group of extensor / ipsilateral rotators (erector spinae, splenius capitis, splenius cervicis)
      • right or left extensor / contralateral rotators (semispinalis, multifidus, rotatores)

    Use the points that you have drawn as references to understand each muscle's actions. For example, observe that the points approximate, or move closer together, as the muscle shortens and produces its action at the intervertebral joints.

    If you prefer, you may use the points you have drawn to construct conventional lines of application. You may also reproduce diagrams, including these transverse planes views of the pelvis and ribcage, understand a muscle's contribution to rotation.

  3. Choose a lumbar intervertebral joint, and analyze its movement during the following activities. For each activity, determine gravity's effect on the trunk, then use the information from the previous exercise to decide which muscles are active during the movement. Decide whether the muscles' actions are isometric, eccentric, or concentric.
    1. From a standing position, pick up an object from the floor directly in front of you.

    2. From a supine position, roll to the right by moving shoulders first.

    3. From a supine position, roll the to right by moving the pelvis first. (This rolling strategy involves closed-chain motion. In the spine, a closed kinematic chain motion is one in which the spine's inferior portion moves while the superior portion is relatively stable.)

    4. While supine, perform a straight leg raise while you palpate your anterior trunk muscles (abdominals). Diagram and explain the muscle activity. Name the trunk muscle or muscles that are active and decide whether the activity is isometric, eccentric, or concentric.

    5. Similarly, abduct the left hip while lying on the right side. You can palpate trunk muscle activity that is similar to what you observed in the previous problem. Diagram and explain the muscle activity. Name the trunk muscle or muscles that are active and decide whether the activity is isometric, eccentric, or concentric.

  4. Describe and analyze an activity that involves trunk movement. With your lab group, present your analysis, including your assessment of the effects of gravity and activity that results in muscles of the trunk.

Last updated 10-14-01 © Dave Thompson PT
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