A: What is the Femur?

Right femur. Anterior surface.

Image via Wikipedia

Q: What is the Femur?

Answer: b) Thigh bone

The Femur is the thigh bone.  It is the longest and largest bone in the human body.  The top-most part of the femur bone is called the head of the femur, it is round like a ball. Otherwise known as the Femoral Head, it fits into the socket, a cup-shaped cavity (acetabulum) of the pelvis; also commonly known as the hip socket.  Collectively, the acetabulum and the head of the femur make up the hip joint.

In the diagram of the pelvis from the Q&A: Sitting Bones you will notice the cup-shaped cavity (acetabulum) or socket, just below and to the outside (lateral) of the Ilium, which I’ve described as elephant ears. Imagine the Femoral Head fitting nicely within the socket.

The Femoral Head, as a result of it’s shape has the ability to move in many directions. Lets review some of these directions.  From a standing position consider these terms of motion:

  • Hip-Flexion: From standing, lift your leg up as if to take a giant step which brings the femur parallel with the floor, this is hip-flexion.  Another example of hip-flexion with both hips simultaneously is simply sitting onto a chair or doing a half squat.
  • Hip-Extension: Bringing the femur behind your body-as you do each time you walk. Another example of extension is when you are lying face down on the floor, with legs straight and together at the mid-line, lift one straight-leg two inches off the floor.  Emphasize the femur lifting from the floor not the knee or foot.  Feel the difference when you focus on lifting from the femur as opposed from the foot. This is hip-extension.  An activity you will find this movement in is flutter kick.
  • Hip-Abduction: Take the femur away from the midline, in a lateral direction, this is hip-Abduction.
  • Hip-Adduction: From the previous hip-abduction position, return the femur towards the mid-line, adding the legs together, this is hip-Adduction.  Example of a physical exercise incorporating both hip-Abduction & hip-Adduction is a jumping jack. Try it emphasizing the movement originating from your feet to open and close your legs, then try it again with originating the movement from the femur.  Notice the difference.
  • Circumduction: Is a combination of the previous four movements: flexion, extension, abduction and adduction.  This type of movement pattern creates a circular motion with the femur. Circumduction occurs at synovial ball and socket joints such as the hip and shoulder joints as well as the fingers, hands, feet and head. An example of curcumduction is the full 360 degree wind-up a pitcher does for an underhand pitch.

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