My thumb is swollen and bruised and hurts . could it just be jamed frind fell on it ! he is about 80 pounds and he bent the thumb backward's

A : A thumb that hyperextends or is forced backward could not only be "jammed" ie have a joint bruise, it could have a ligament injury that needs treatment. An ulnar or radial collateral ligametn injury can be partial requiring immobilization or it may be completely torn often requiring surgery. An exam by a hand surgeon, sometimes leads to an mri, sometimes to splinting or casting and at times surgery. Faliure t-o care for these injuruies can lead to long term issues with the thumb as it is used in grasping.