Facts About the Human Arm



  • The arm is made from three long bones, linked by a hinge joint at the elbow.
  • The two bones of the lower arm are the radius and the ulna.
  • The radius supports the thumb side of the wrist.
  • The ulnar supports the outside of the wrist.
  • The wrist is one of the best places to test the pulse, since major arteries come nearer the surface here than at almost any other place in the body.
  • 17w intricate network of bones in your hands enables you to perform delicate and complex movements like writing or playing a musical instrument.
  • The upper arm bone is called the humerus or, jokingly, the funny bone.
  • The two major muscles of the upper arm are the biceps (which bends the elbow) and the triceps (which straightens it).
  • The hand is made from 26 bones, including the carpals (wrist bones), the metacarpals (hand bones) and the phalanges (finger bones).
  • There are no strong muscles in the hand. When you grip firmly, most of the power comes from muscles in the lower arm, linked to the bones of the hand by long tendons.
  • The shoulder is one of the most flexible but least stable joints of the skeleton, since it is set in a very shallow socket. But it is supported by six major muscle groups, including the powerful deltoid (shoulder) muscle.
  • Look at the inside of your wrist on a warm day and you may be able to see the radial artery beneath the skin.