The biceps (long head and short head) are the muscles of the upper arm and they attach to the radius (forearm bone) with a tendon.  The distal biceps tendon can rupture or tear off of the forearm bone from acute trauma.  The most common cause is a forceful extension of the elbow against heavy resistance, seen commonly with lifting heavy objects.  Rupturing the distal biceps tendon will result in pain, bruising and swelling of the biceps near the elbow crease.  Distal biceps tendon ruptures will also lead to weakness and difficulty moving the arm in a twisting motion, like using a screwdriver, as well as some weakness in bending the elbow.  Surgery is recommended to reattach the tendon in active individuals and athletes and restore the strength of the upper extremity.  Occasionally, therapy, pain control, and maintaining mobility may be recommended before surgery is considered based on the nature and chronicity of the tear as well as other patient factors.