1. Chapter 24: The Spine

2. Copyright ©2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 2 Reflexes  Many of the body’s reflexes allow for testing of nervous system integrity.

3. Copyright ©2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 3 Patellar (Knee-Jerk) Reflex  This commonly tested reflex is accomplished by tapping the patellar tendon, which stretches the quadriceps muscle, stimulating that muscle’s stretch receptors.

4. Copyright ©2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 4 Patellar (Knee-Jerk) Reflex (cont.)  A nerve signal is sent to the spinal cord, which reflects back through a motor neuron to the quadriceps and causes contraction.  Quadriceps contraction causes the lower leg to extend.

5. Copyright ©2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 5 Flexor (Withdrawal) Reflex  This reflex is usually activated in response to some potentially injurious stimulus, such as stepping on a sharp or hot object.

6. Copyright ©2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 6 Flexor (Withdrawal) Reflex (cont.)  A receptor located in the skin responds to pain. A nerve signal is sent to the spinal cord, where it reflects through a motor neuron to flexor muscles such as the leg’s hamstrings, causing the limb to pull away from the stimulus.

7. Copyright ©2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 7 Plantar Reflex  Tests the integrity of the lower spinal cord.  A reflex hammer is pulled along the sole of the foot with pressure applied.  The normal response is a curling of the toes.

8. Copyright ©2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 8 Plantar Reflex (cont.)  If damage is present, an abnormal reflex response is a spreading of the toes and lifting of the big toe, also known as Babinski’s sign.

9. Copyright ©2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 9 Nervous System Anatomy  Although other cells help with support and nourishment, the only cell that can communicate impulses to other cells is the neuron.

10. Copyright ©2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 10 Gray and White Matter  Gray matter consists mostly of neuron cell bodies.  White matter consists mostly of myelinated nerve fibers.

11. Copyright ©2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 11 Gray and White Matter (cont.)  Gray matter is found in the center of the spinal cord and is surrounded by white matter.  In the brain there is an additional outer gray matter layer, the cerebral cortex.

12. Copyright ©2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 12 Spinal Injuries  Trauma to the spine can produce devastating injuries, including paralysis and death.

13. Copyright ©2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 13 Jaw-Thrust Maneuver  This is the safest method to restore breathing when neck injury is suspected.  The mandible is brought forward by placing fingers behind the jaw angle and lifting.

14. Copyright ©2004 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 14 Intervertebral Disc Herniation  A structural defect in which the softer nucleus pulposus protrudes through the tough annulus fibrosus