Chief complaint: 19-year-old man with broken back.

history: allen dexter, a 19-year-old college student, was rock climbing when he fell 30 feet to the ground. paramedics arriving at the scene found him lying in the supine position, unable to move any extremities and complaining of neck pain. he was alert and oriented to his current location and the details of his fall. he complained that he could not feel his arms and legs. his pupils were equal and reactive to light. his vital signs revealed a blood pressure of 110 / 72 and a heart rate of 82 beats per minute. breathing was steady but shallow. the paramedics immobilized his neck and transported him to the trauma center. upon examination allen had some sensation in his arms, but could not localize touch or describe texture. he was able to raise his shoulders and tighten his biceps brachii slightly in each arm, but could not raise either arm against gravity. his lower extremities were flaccid, despite attempts to move them. vital signs were taken again at the hospital and were as follows: blood pressure = 94 / 55; heart rate = 64. x-rays taken upon arrival revealed a fractured vertebra at a particular location. allen was transferred to intensive care and his condition was stabilized. guiding questions

1. allen's heart rate and blood pressure were abnormally low, but we would reasonably expect the opposite in times of high stress. which division of the autonomic nervous system allen's symptoms suggest is most active in this case? what is the cause of this phenomenon? be sure to provide a description of which neurons are affected/not affected.
2. which vertebral bone do you think was fractured? how did you you make this determination? give specific reasons for your answer and be sure to relate this both to the skeletal muscles which are affected and the changes in general sensation that are noted.
3. what is the primary muscle of respiration under normal circumstances and what nerve innervates this muscle? what are the accessory muscles of respiration? does innervation of those muscles arise in the same or a different level of the spinal cord?
4. which spinal nerves contribute nerve fibers to the nerve you named in question #3? what is a benefit of redundancy in nerve input to named nerves? is there any significance to the description of his breathing by the paramedics on scene?
5. what is a possible treatment for the patient in this case study. how could this treatment improve conditions for the patient? are these improvements seen at the cellular, tissue, organ or systemic level?