Balancing Front and Back Crotch Hook Lengths

I’ve covered a lot about balancing pants from left to right, but I haven’t talked about balancing pants from front to back. The purpose of this post is to talk about something I’ve not seen discussed, and that is about getting the crotch point location correct. I will show you how to find your crotch point and what happens if your crotch point is too far forward or backward, even if you have the correct crotch length.

Melly Sews has a great tutorial about crotch lengths that are too short or long or if the curve is too steep or curvy. These issues are pretty apparent since you know when you have a wedgie in the front or back of your pants. I want to discuss what happens when the crotch curve fits in size and length but isn’t balanced, so it doesn’t drape correctly!

Definitions

Let’s start out with some definitions.

• Crotch length is the length from the top of center front in between your legs to the top of center back.
• Crotch point is at the bottom of the pelvic floor and is where the front crotch curve and back crotch curve meet.
• Crotch level is the horizontal line that goes through the crotch point.
• Crotch depth is the perpendicular measurement from the crotch level to your front and back waistband. The crotch depth can be different for the front and back if your waistband sits differently front to back.
• Crotch width is the empty space between the front and back pieces where your body will reside in the pants when worn.

I’ve never found measuring the crotch length or depth particularly helpful in determining where the front curve meets the back curve. Both measurements depend on waistband placement, which changes from pattern to pattern. Crotch width is hard to translate because it is defined by empty space and changes depending on the horizontal level you measure. Crotch width is often measured 2 inches above your crotch point, which feels like an arbitrary point. I don’t like random points.

I prefer using crotch hook length. To obtain this measurement is to draw a horizontal line at the crotch level. My image above contains a 3/8 inch seam allowance, which is why the crotch level is slightly lower. Next, draw a line vertical from the center front or center back down to the crotch level. The crotch hook length is the distance from where these two lines meet to the inseam. I have a crotch hook length of 5 inches for the back. I have a crotch hook length of 4.5 inches for the front.

Yes, I understand the crotch hook length uses the location of your waistband, so I haven’t addressed that issue. But for me, this is an easier way to obtain the crotch width. I’m measuring the pattern and not measuring the void between patterns. I don’t have a magic ruler that can measure through my body, exactly 2 inches above my crotch point.

How to Find Your Crotch Point

Anatomically the crotch point should hit at the center of your perineum, the yellow dot on the diagram. Towards the back body, you have the anus, and towards the front body, you have the scrotum (male) or vulva (female). The center of your perineum is halfway in between.

If anatomy just isn’t your thing, you can also use a plumb bob to find your crotch point. I cut two long pieces of string. One piece of string was held like I was trying to measure my crotch length, and the second piece of string was securely fastened at the center with a heavy-ish object hanging from it to act as a plumb bob.

How to Measure Your Crotch Hook Length

I haven’t been particularly successful in accurately measuring my crotch hook length because the body squishes, which can distort values. I’ve tried taking my L-shaped ruler and placing the vertical portion gently against my body while keeping the horizontal portion level. If you know your crotch point, you can find that point on the ruler to obtain your crotch hook length (yellow arrow on body, red arrow on pattern). This measurement isn’t entirely precise, but it will give you a general idea of length.

Again, I don’t find this measurement perfect, but it is helpful to get a general idea. I place my L-shaped ruler gently again my body while keeping the horizontal portion perfectly level. The crotch hook length is the distance to your crotch point (yellow arrow on body, red arrow on pattern). Many patterns have front crotch hook lengths of ~1.5 inches, but clearly, I knew I needed to add more length from this method!

Perfect Fit

Let’s say you have a pant pattern, and the crotch area fits perfectly. The crotch length is long enough, the crotch hook length is just right, so you don’t have any unfortunate wedgies, and your crotch depth is just right that the waistband sits just right.

What would happen if the crotch point was shifted forward or backward?