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updated February 12, 2004

Instructions for the Paper Pelvis!


On this page, this: becomes this:


NOTE: Colored tape may be used to show you how to best
      tape certain muscles.  You can use clear tape.

NOTE: The color for these pictures have been adjusted
      by me... so the pelvis in one picture may look
      orange, and then red in the next picture.  It's
      consistently just one model throughout.

HINT: The more careful you are in the beginning, the
      better the result will be.

HINT: For taping things, try putting the tape on the
      smaller attachment first and then aligning and
      fixing it to the larger element.

HINT: The DOTTED LINES are there to help you align
      certain pieces. (Don't cut them.) ...............

      The DASHED LINES interspersed with a shorter 
      dash are to be folded back, the two sides away 
      from each other. ___ _ ___ _ ___ _ ___ _ ___ _ __

      The NORMAL DASHED LINES are to be folded forward, 
      the two side toward each other. ___ ___ ___ ___ _

      The ZIG-ZAG should be curved with the two sides
      toward each other. /\/\/\/\/\/\/\/\/\/\/\/\/\/\/\

      The ))) LINE will be covered by a ligament later.
                          
      The SOLID LINES are for cutting. ________________

(1) Cut out the bones.
The result should look like this.


b1

(2) Fold at the dashed lines. (see the last hint above) The result should look like this.

b2



b3

(3) Get the transparent tape ready. Line up the two dotted lines shown below and then tape it up well. See below for what you should get. Be sure that it's aligned well and taped securely.

b4

The result should look like this.

b5



b6

(4) For the coccyx, you can curl it in a little, just so it looks a little more realistic.

b7



b8



b9

(5) Cut out the ligaments. The result should look like this.

c1

(6) Tape the ligaments to the bones. Each ligament is labelled right and left. Don't confuse your right and left with the model's. ;-) It's pretty straightforward, except for the sacrospinous and sacrotuberous, for which you want to be more careful in aligning the ligaments and a bit more stingy on the tape. Many things will travel through the foramens you create. For the sacrospinous, try to cover the marks drawn on the bone. The marks look like this ))))))))))) Consult your anatomy book if the pictures are not clear enough. Suggested order of applying the ligaments:

d1



d2



d3



d4



d5



d6



d7

(7) Cut out piriformis and obturator internus. Apply them as shown below. For muscles, try to tape only the origin and the insertion for realism. Piriformis exits the greater sciatic foramen, and obturator internus exits the lesser sciatic foramen, which is created by the sacrospinous and sacrotuberous ligaments. After exiting, obturator internus is pulled toward the greater tubercle of the femur where it inserts. This is in the direction of the obturator foramen. NOTE: the femur attaches just above the obturator foramen. See an anatomy book for details.

e1



e2



e3

(8) As shown below, pull the tendons for the obturator internus and piriformis muscles toward the greater trochanter of the femur and tape them together to show how they would insert.

e4

(9) Levator ani (which includes puborectalis, pubococcygeus, and iliococcygeus) and coccygeus is best taped in the order shown below. For these pictures, I didn't cut out the holes for the anus, vagina, or urethra, but I meant to have them cut out. :-) It's helpful to know where the holes are.

f1

Not pictured well... but the ventral notch above the urethra should be taped together too.

f2

(10) For those with large hands this may be a frustrating step. Trying taping the ventral side first with some tape already on the levator ani, and then just fixing it to the bone. See pictures for proper alignment. After that, tape the dorsal side to sacrum. One alignment to watch out for is how iliococcygeus goes toward the ischial spine and how coccygeus inserts to the spine. The best alignment tactic is shown in "g4" where the end of the coccyx is at the same level as the angle in the muscle dorsal to the analrectal hiatus.

g1



g2



g3



g4

Here are some random pictures for your perusal.

h1



h2



h3

The story...
When I was a first year medical student studying for the anatomy exam on the pelvis, I found it hard to visualize where everything was in relation to everything else. So I took some paper and made some molds of a pelvis, first with the bone, and then with some ligaments and muscles, using Netters as a guide. Then I went through with some yarn and tape to place the major nerves and blood vessels. It really took some thought to place everything in the correct place, and it paid off in the end. Visual memorization or route memorization is good for some things, but they can't compare with interacting with a subject.
I'm not yet satisfied with what I've designed so far, since it is still missing some major structures and I don't have any instructions on nerves and blood vessels yet. And it is only the female model, and the male pelvis is pretty different. Basically, the project is not done yet.
I suggest that you cut out your own perineal membrane along with the muscles in that area. Use Plate 352 in Frank Netters's Anatomy as a guide. And then use different colored yarn for nerves and blood vessels (i.e., internal pedundal artery--> perineal artery, inferior rectal)
Good luck!

I've copyrighted the book. Please do not attempt to reproduce it. It's taken me a very very long time to refine the model to its present state.

If you have any questions/suggestions/compliments for this page, you can email me, Wei-Shin Lai at weishin@earthlink.net. If you would like a copy of this book, I can send it to you as long as you cover the postage. Just email you address to me. And then, please please give me some feedback after you try making it. Thanks!