Sports injury: shoulder sling recommendation for student living in the city. on saturday morning i dislocated my shoulder and sustained a hairline fracture on the top ball of my humerous bone. my doctor is recommending that i fully immobilize my right arm

First, : First, i think you should find a nearby orthopaedic surgeon who can monitor and care for you locally. The fracture, as you describe, may have been a "hairline" fracture when you were first seen, but could become a displaced fracture with time and/or use of he shoulder. That is probably why a sling and immobilization was recommended. To limit swelling in the hand, move your fingers frequently and make a fist or squeeze a soft ball or ball of socks throughout the day. Follow-up x-rays are important to help determine that the fracture remains "in place". You can expect that stretching and physical therapy will be advised when the fracture is "stable", or unlikely to displace. The injury you sustained can lead to ongoing problems, even if it is cared for appropriately. To minimize this risk, find a trusted local orthopaedic surgeon, preferably one that cares for shoulders and/or sports injuries, and follow their advice as this is a common injury. If you let their office know you have a fracture, many orthopaedic surgeons will make efforts to get you a quick access appointment. Though it has been 20 days since your post, it is not too late to make sure it is healing in good position. Good luck!

Sling and swathe: Buy a shoulder sling that has a strap that goes around your waist to best immobilize it. This is called a shoulder immobilizer aka a sling and swathe. You really cannot cast a shoulder unless you want it wrapped around your chest. Also you may find sleeping in a easy chair or recliner will be much more comfortable for the first week or so.