2. Prolonged, painful involuntary contraction of skeletal muscle. Caused by: An imbalance of the salts in the body, fatigue, or stress Symptoms: Pain

3. Injury to a ligament Caused by overstretching Gradually heals, but may take months

4. Excessive stretching or working of a muscle, resulting in pain and swelling of the muscle Damage to muscle caused by overstretching

5. Characterized by pain between the knee and the ankle Usually occurs in athletes Caused by repeated injury to the muscles around the tibia

6. Chronic aches, pains, and muscle stiffness and heightened response to pressure No known cause

7. The partial or total loss of the ability of voluntary muscles to move May be either temporary or permanent

8. Symptoms: Mental retardation, muscle weakness that slowly gets worse causing muscles to lose strength, frequent falls, and drooping eyelids Inherited disorder No known cure

9. Disorder of the peripheral nervous system that causes limp muscles and loss of reflexes Begins with the feet and lower extremities and works toward the head Patients return to normal over time, weeks or months

10. Myasthenia Gravis - An autoimmune disorder occurs when the immune system mistakenly attacks healthy tissue. -The body blocks the muscle cells from receiving messages from the nerve cell. - Causes weakening of voluntary muscles so you have trouble chewing, talking, moving, etc. May cause facial paralysis

11. Intense muscle spasm or cramp (prolonged muscle contraction) resulting in rigid paralysis. Caused by a toxin of a bacteria entering the body through an injury Treated with antibiotics and prevented with vaccinations Tetanus