A Spill at Parsenn Bowl: Knee Injury and Recovery - Part I - Case Study Collection - National Center for Case Study Teaching in Science

Part I – The Slopes

Elaine was enjoying a pleasant day on the ski slopes at Winter Park. When she got on the lift to the top of Parsenn Bowl (12,000 ft), the weather was fine—windy, but sunny. During the 5- or 10-minute ride, the weather changed suddenly; it became a white-out, with icy surface snow, blowing snow, a very strong wind, and extremely low visibility. Many people fell as they got off the lift, including Elaine. However, she got up and joined her family members as they stood, wondering just how they were going to get down the mountain. Meanwhile, the lift closed due to the terrible conditions (50-mile-an-hour wind and a temperature of −20° F). As she adjusted her stance, Elaine somehow twisted and fell again, which resulted in external rotation of her right knee. There was no pain at the time and she thought she could get up and prepare to get down the mountain, but her knee was too unstable. While she sat on the icy surface, her husband notified the lift operator to call the Ski Patrol. In about 20 minutes they arrived and put her on a sled, which they skied down the slope; when they reached the Ski Patrol headquarters, they transferred the sled to a snowmobile and promptly got her down the mountain and into the emergency room.

Questions

What mechanisms did Elaine’s body employ to maintain homeostasis?
1. Where are the sensors for cold?
2. Where is the “thermostat” of the body located?
3. What is the effector (i.e., what tissues are involved) for the blood vessel constriction? For the shivering?
What areas of the body would be the most vulnerable to frostbite?

Go to Part II – The Emergency Room

Date Posted: September 30, 2009.

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Originally published at http://www.sciencecases.org/knee_injury/case1.asp