Dan injured the spinal nerves emerging from the lower lumbar and sacral region of the spinal cord during a horse-riding accident. After his injury, he reported numbness in his feet. Explain the connection between the loss of sensation he has described
and the plexus responsible for serving this area.
What will be an ideal response?
The sacral plexus forms from the anterior rami of spinal nerves L4 - S4. Rami are mixed nerves, housing both sensory and motor neurons. The sciatic nerve is the largest nerve of this plexus. It splits into two main branches, the tibial nerve and the common fibular nerve. The tibial nerve divides into its terminal branches which serve the muscles and skin of the foot at the level of the medial malleolus of the tibia. Since Dan reported loss of sensation in his feet, the sensory neurons of the sciatic nerve must have sustained injury after his accident.
You might also like to view...
Choose the most correct response. Which type of flow is most efficient?
A) Concurrent B) Countercurrent C) Crosscurrent D) It depends on the rate of flow of both the blood and the respiratory medium.
Vital signs include all of the following EXCEPT ________.
A. coloring B. heart rate C. respirations D. temperature
A presynaptic neuron releases neurotransmitters to be received by a postsynaptic neuron. Which general property of neurons does this presynaptic neuron demonstrate?
A. Irritability B. Conductivity C. Excitability D. Secretion
The autonomic division of the nervous system directs
A) processes that maintain homeostasis. B) behavior. C) emotions. D) voluntary activity. E) conscious control of skeletal muscles.