Appendicular Skeleton: Functions and Anatomy

Appendicular Skeleton: Functions and Anatomy
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  • 0:06 Appendicular Skeleton
  • 2:06 Upper Limbs
  • 3:25 Lower Limbs
  • 4:45 Lesson Summary
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Lesson Transcript
Instructor: Heather Adewale

Heather has taught reproductive biology and has researched neuro, repro and endocrinology. She has a PhD in Zoology/Biology.

Without your skeleton, what would you be? Pretty much just a lump of muscle and tissue, right? Learn about the parts of the skeleton responsible for movement in this lesson on the appendicular skeleton.

Appendicular Skeleton

Have you ever thought of the human body like a big puzzle? Well, essentially, it is like one of those cool 3D-style puzzles. The skeleton has over 200 bones (or puzzle pieces), and just like you divide a puzzle up into edge pieces and center pieces, the human skeleton can also be divided up. The center pieces, in this case, are called the axial skeleton, and they have been covered in another lesson, while the edge pieces would be like the appendicular skeleton.

While the axial skeleton makes up the inner framework or trunk of the body, the appendicular skeleton includes the outer limbs and the bones that connect the limbs to the center or trunk of the body.

These are the movable pieces - the arms and the legs - that allow the body to move. Without the appendicular skeleton, the axial skeleton - the head, ribs and spinal column - wouldn't be able to go anywhere.

The appendicular skeleton is made up of the arm, leg and hip bones.
Appendicular Skeleton Diagram

And, while you may think the axial skeleton is more important because it contains the brain and the organs, just think of all the things you wouldn't be able to do without an appendicular skeleton - no running, walking or dancing, not even writing, hugging, eating and so much more! So, like many other things in biology, both parts are much better together than they would be on their own.

Let's take a look at some of the members of the appendicular skeleton.

  • The upper limbs include the bones of the arms and hands.
    • These are attached to the top of the rib cage by the pectoral girdle.
  • The lower limbs include the leg and foot bones.
    • These are attached to the lower part of the spinal column by the pelvic girdle.

All together, the appendicular skeleton contains about 126 bones - that's 60% of all the bones in the human body!

Upper Limbs

Of these, 54 are found in the hands and wrists alone! Hmm - might explain why, out of all the parts of our body, the hands can perform some of the more complex motions. You see, the upper limbs are adapted for free range of motion; you will notice that you probably have more ability to twist and move your arms and wrists in more ways and directions than you can your legs. You will notice that the number of bones in the upper limbs increases as you move from the shoulder down towards the fingertips.

The top part of the arm, above the elbow, consists of one bone, the humerus. This is connected to the two bones in the lower arm, the radius and ulna, which are below the elbow but above the wrist. The lower arm is connected to the wrist, which is made up of carpal bones. These, in turn, are connected to the fingers, which are made up of metacarpal bones and phalanges.

The bones that make up the upper limbs
Upper Limb Bones Diagram

Okay, so now that we have the arms established, how are they connected to the axial skeleton? Well, that is the job of the pectoral (or shoulder) girdle. This forms the shoulder joint, connecting the upper arm to the top of the rib cage.

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