11. There are – pairs of sacral spinal nerves. 12. Cervical spinal nerve pair Cl originates between the foramen magnum of the occipital bone and the 13. Spinal nerves L4 through S4 form a plexus 14. The gray matter of the spinal cord is divided into anterior, lateral, and posterior 15. The spinal cord ends just inferior to Ll in a tapered point called the 16. Severing the nerves of the cervical plexus would cause breathing to cease. 17. The inferior and superior gluteal nerves of the plexus intervate the gluteal muscles of the buttocks. PART D: Assessments Complete the following 1. To block chronic pain in a patient, sometimes doctors will sever the posterior root of a spinal nerve. Provide a rationale for such a procedure. 2. Describe what the result would be if the anterior root of a spinal nerve were severed? 3. Injuries to the vertebral column and spinal cord are always of concern. Explain why injuries, especially to cervical regions, are of the greatest concern. Include specific cervical areas as part of your answer. CRITICAL THINKING ASSESSMENT Why are intramuscular injections given in the gluteus medius muscle rather than in the larger gluteus maximus muscle in the buttock region? CRITICAL THINKING ASSESSMENT Incorrectly using a crutch may cause impaired sensory or motor function to the arm, forearm, and hand as nerves are compressed, creating a condition called crutch paralysis. What nerve plexus is involved? How might a person who uses a crutch avoid this injury?
The correct answer and explanation is:
Here are the answers and explanations to the questions provided:
PART D: Assessments
1. To block chronic pain in a patient, sometimes doctors will sever the posterior root of a spinal nerve. Provide a rationale for such a procedure.
The posterior root of a spinal nerve carries sensory information from the body to the spinal cord. By severing the posterior root, the transmission of pain signals from the affected area to the brain is interrupted. This procedure is typically performed in extreme cases where chronic pain is debilitating and other treatments have failed. However, it is a drastic measure, as it also results in loss of sensory input from the affected area, including touch, pressure, and temperature.
2. Describe what the result would be if the anterior root of a spinal nerve were severed.
The anterior root of a spinal nerve carries motor signals from the spinal cord to muscles, enabling voluntary and involuntary movements. Severing the anterior root results in the loss of motor function (paralysis) in the muscles innervated by the affected nerve. However, sensory functions, such as touch and pain perception, remain intact because these signals are carried by the posterior root.
3. Injuries to the vertebral column and spinal cord are always of concern. Explain why injuries, especially to cervical regions, are of the greatest concern.
Cervical spinal cord injuries are particularly concerning because the cervical region controls vital motor and sensory functions, including breathing and movement of the upper limbs. Damage to higher cervical levels (C1–C4) can impair the diaphragm, leading to respiratory failure, and injuries at C5–C7 can result in quadriplegia. Injuries to this region are also more likely to impact both motor and sensory pathways, given the high density of nerves passing through the area.
CRITICAL THINKING ASSESSMENTS
Why are intramuscular injections given in the gluteus medius muscle rather than in the larger gluteus maximus muscle in the buttock region?
Intramuscular injections are given in the gluteus medius muscle to avoid injuring the sciatic nerve, which runs deep and close to the gluteus maximus muscle. The gluteus medius provides a safer site as it is located higher on the hip and away from major nerves and blood vessels. Administering injections in this area reduces the risk of nerve damage, pain, and complications.
Incorrectly using a crutch may cause impaired sensory or motor function to the arm, forearm, and hand as nerves are compressed, creating a condition called crutch paralysis. What nerve plexus is involved? How might a person who uses a crutch avoid this injury?
Nerve Plexus Involved: The brachial plexus is involved in crutch paralysis. This plexus originates from spinal nerves C5–T1 and supplies the upper limb, including the arm, forearm, and hand.
How to Avoid Injury:
Crutch paralysis occurs when crutches are used improperly, causing prolonged compression of the brachial plexus near the axilla (armpit). To prevent this:
- Ensure crutches are adjusted to the proper height, leaving 2–3 inches between the armpit and the top of the crutch.
- Use the hands, not the armpits, to bear weight while using crutches.
- Regularly shift weight to avoid prolonged pressure on the axillary region.
By following these measures, the risk of brachial plexus compression can be minimized.