Of the 206 bones in your body, three of them are in your arm: the humerus, radius, and ulna. Your arms are also made up of muscles, joints, tendons, and other connective tissue. Injuries to any of these parts of the arm can occur during sports, a fall, or an accident.
Types of arm injuries include 
Tendinitis and bursitis	
Sprains	
Dislocations	
Fractures (broken bones)
Nerve problems
Osteoarthritis
	
You may also have problems or injure specific parts of your arm, such as your hand, wrist, elbow, or shoulder.