Explanation of Facts: 1. Not using left back leg properly: This tells us where the problem is and helps us to begin forming a problem list. 2. Spayed Female Black Lab: This is a large breed dog. This information is helpful because large breeds tend to have their own specific sets of problems in terms of their musculoskeletal system. 3. 6 years old: Bonnie is an older dog which would suggest that she's more likely dealing with an injury or acquired problem more so than a congenital one. However, the problem could still be congenital. 4. No history of trauma or other injuries in 5 years: This is important because it indicates that this problem probably hasn't been caused by a past injury. 5. Humane Society dog: Because Bonnie is a pound puppy, her parents' conformation and heritage are unknown. This could make her more prone to congenital problems such as hip dysplasia. 6. Hasn't been walking normally since Wednesday: This gives us an idea of how long the problem has been going on....seemingly relatively acutely. 7. Difficulty getting up and using the stairs: This indicates that Bonnie has the most troubles during weight bearing exercise. 8. No other pets at home: This rules out injury that could be caused while playing with another animal. 9. Fed 4 cups of Hill's Maintenance a day with fruit for treats: This is a good quality diet and therefore reduces the chance that Bonnie's problem is due to a low quality plane of nutrition. The amount is about right for a dog of her size. 10. Been in for checkups and up to date on all shots and deworming: This indicates that other than her current lameness, she should be the picture of health. 11. Not on any medication besides heartworm preventative: Indicates that Bonnie has not other health problems. 12. Very active and goes for walks, runs, and hikes: This indicates that Bonnie participates in activities that could cause injury to her joints and limbs. 13. Partial weight bearing L hind limb lameness: This further indicates where the problem is. 14. Has difficulty getting up but can walk quite well once she is up: Again, this indicates problems during weight bearing activities. 15. When she stands still, she is barely toe touching on her L hind: Again, she has problems with weight bearing. 16. Effusion of the left stifle joint with a distension of the joint capsule on either side of the straight pateller ligament: This isolates the problem to her stifle. 17. Pain on manipulation of the stifle: This also isolates the problem to her stifle. 18. Overweight: This is important because excess weight increases wear and tear on joints. 19. Joint tap performed: This would be even more helpful if we knew the results of the tap. 20. Under sedation a 4-5mm cranial drawer on the L stifle: This is indicative of a cranial cruciate rupture. 21. Less than 2mm cranial drawer on the right: This is relatively normal indicating that Bonnie's left stifle is abnormal. 22. The patellas are normally positioned and mobile: This helps to rule out luxating patella as the cause for Bonnie's pain. 23. Collateral ligaments are intact: This indicates that there are no problems here and helps narrow our focus to the CCL. 24. No palpable laxity in the hips: This helps to rule out hip dysplasia. 25. No pain during full range of motion on the hips: This also helps to rule hip dysplasia or any other hip disorders.