"An honorable man or woman will personally commit to live up to certain self-imposed expectations. They need no outside check or control. They are honorable in their inner core." —James E. Faust (Ensign, May 1982)
This chapter investigates the head, neck and trunk. By the end of this chapter, you should be able to:
Identify the segments of the vertebral column;
Express the differences in the various spinal regions;
List the primary muscles of the cervical, thoracic, and lumbar regions and their functions;
Explain the mechanisms of trunk motions and how the spine is stabilized during motion;
Discuss the relationship between the pelvis, low back, and trunk and their contributions to functional movement;
Demonstrate the motions of the pelvis: anterior and posterior pelvic tilt;
Identify muscles and functions of the temporomandibular joints.
Kamryn has been working with Matt, a patient who has been unable to work because of a back injury. Matt injured his back as he was moving a box onto a truck for delivery from the warehouse where he has been working for the past 10 years. This is his first injury on the job. Matt is anxious to get back to work, but before he can be released for full duty, Kamryn must instruct him in proper body mechanics. She is well aware of the stresses that poor mechanics place on the spine, and throughout his treatment course, she has tried to impress the importance of good body mechanics to her patient. Today, she will instruct him how to bend over to pick up a box the proper way so he does not risk another low back injury.
Included in the axial skeleton are the head, vertebral column, sternum, and ribs. The head is closely related to the vertebral column, or spine, as its position influences the position of the spine, as we will learn in this chapter. The axial skeleton serves as an intermediary to transfer and absorb forces between the upper and lower extremities. As we move through this chapter, it should become readily apparent why the axial skeleton is so important to upper and lower limb function.
The vertebrae, ribs, and jaw have multiple purposes that frequently must be carried out simultaneously: protecting organs (spinal cord and viscera); providing the vital functions of breathing, chewing, and swallowing; supporting head, arms, and trunk (HAT) against the force of gravity; transmitting forces between upper and lower extremities; and providing stability and mobility for hand function, locomotion, and other activities. The anterior portion of the vertebral column (bodies and discs) provides for weight-bearing, shock absorption, and mobility in all directions. The posterior portion of the column provides for protection of the spinal cord, guidance and limitation of motion, and elongated processes to increase the leverage of muscles of the trunk and extremities.