Contemplating Pants Fitting: Crotch Shapes

originally published 2/4/12


I also need to review and contemplate the various crotch curves used in the pattern making industry. My reviews may not do anything for you other than expose how little I know. But I need to do these reviews. I need to think back over the past 4 years as to what I’ve done; what I’ve read; what I’ve learned.  The Fashion Incubator has a number of informative posts on the draft of pants and how that affects the fit. I should go and re-read them because mostly I remember about the problems of Camel Toe and how it is being created.  Camel Toe is not one of my problems. Once I realized I needed to shorten the length of the front crotch, my front pattern issues were solved.  My issues are with the back.  I need to understand the various back crotch curves and what my alterations do to each.


I think the most common crotch is the J (or mirrored J depending on which side you are looking at). Typically the back crotch has a wider extension that the front but put the two together and the complete crotch looks like a U. The point is there is a fairly upright crotch which ends in a shallow curve.  This curve fits and works for a number of bodies. A few more need either to add to the length of the center back or they need to extend the shallow curve a little bit longer.  I need to do both with substantial amounts.  I’ve had patterns where I extended the shallow curve 3 FULL INCHES.  I have nearly as much depth as I do width. I am a classic pear. Burda does a nice version of the J curve.  Not all, but several of the Burda pant patterns fit me perfectly.


The next one I hear much about is the L crotch.  The center back is pretty upright and the extension is very straight. There is a little curve where the two straight lines meet but I think that’s just to make it easier to cut. This crotch sent thrills through the sewing world as a large group of women realized it was exactly what they needed.  The L crotch did seem to be more successful in stretch fabrics.  It was not adopted by the Big 4 but used mostly in independent pattern lines.   I’ve never tried it. Meant too but just never bought a pattern with this particular crotch:

I’ve got a patten now that I want to make but hesitate.  The Vogue 8757 back crotch is quite similar to a shallow C.  Let me show it and then continue my thoughts:

I can’t imagine this fitting me.   I need a crotch extension big enough for me to sit on and I am, as written earlier, nearly as deep as I am wide.  A little curve like this would have to struggle to accommodate the depth of my figure.


The crotch that fits me the best, I’m calling a Fish Hook:


This is from Trudy Jansen’s Designer Jean pattern 906.  It has 2 pieces to the back leg. This piece is the center back to inseam pattern.  The crotch is fairly upright, like the others, but it dips down and underneath the top of the inseam, then rises back up to meet the inseam point which would then be joined to the front.  Look at it carefully.  This is a deep curve where the J is shallow and the L practically non-existent. I’ve never had a failure with this pattern. I’ve used denim, stretch-denim, cotton twill, cotton/Lycra twill and plain weave, corduroy, stretch corduroy.  I’ve made shorts, slim legs and nearly bell but at least boot cut jeans. I’ve used this pattern in 2 sizes for 3 years. It never fails me.  OK with a few pairs I have scooped out the bottom a little more.  I looked carefully at my well used pattern and realized that I did add a 1/4″ back wedge.  And just saying, that while pants are often tilted (direction of the grain is modified) depending upon the cut (trouser, slack, jean), this pattern is cut straight on grain like you see it here.