Instruction: Extract information from the supporting document to answer the given question.

Input:
Question: Does this pillow have a curve on the thickest part, meaning it is not completely straight.?
Document: The pillow is for my husband and we have tried many many pillows but this is the only one he finds helps with his neck pain. He wakes with no muscle aches or pains!
I have a chronic neck issue, so this is the best pillow for controlling head and neck rotation while sleeping. It is very comfortable for sleeping on my side or on my back.
As a long time Neck Pillow by Termpur-Pedic user, I was hopeful that the SidePillow would be a better choice, considering I always sleep on my side. What I like about the SidePillow is that it is firm (much more so then a new Neck Pillow).
I've had this pillow for about 10 years. I typically start out on my back and quickly move to my side. I herniated a disc in my neck and needed some relief. It cradles your head and definitely supports your neck while leaving room for your shoulder. Awesome design!
I've used Tempur-pedic contour pillow for over 10 years now. I recently bought this SidePillow and have loved it since the first night! I even packed it in my suitcase to fly and stay at hotel because I was not going to be without it! Awesome nights sleep and no neck pain!
I liked the idea behind this pillow and was anxious to try it because of a compressed nerve. Unfortunately, it is a little too tall to fit in my neck. It seems like the pillow is also designed for someone to not turn over. It's hard to readjust when you do, as it sort of grabs your face. I did receive a slight feeling of claustrophobia.
I have always slept on my side, but recently started having trouble finding a comfortable position for my neck. And I was ending up sleeping really weirdly curled up in ways that might have been contributing to my headaches. This pillow worked for me, better than the traditional tempurpedic neck pillow (which used to be my pillow of choice).
I ordered the pillow in hopes that it would relieve the cramp I get in my nexk at night....and it does! I love the design, since it cradles my neck and allows my head to stay elevated a little, my old pillows just dont support. I wish I had done this 5 years ago...
Update: Feb 9, 2014-Update: I'm changing my review to one star. Why? After several weeks my jaw began to hurt. The curves on this pillow do not accommodate your head as you move around at night. My husband had trouble as well with the neck pillow, it seemed to keep him awake. I'm clever and came up with a solution (since they are not returnable).
In my case, it is too thin of a pillow to give proper support for my shoulders. After sleeping for several hours, I find my shoulders ache. I have tried it on a soft bed and a firm bed several times, still not liking it. I am going back to the neck pillow, which I can get in different sizes which seems to help keep my shoulders from feeling squished.
Answer: The curvature is both on the ends (thickest) and center (thinnest) part of the pillow.  Thus, you have great support whether you sleeps on your back or side (right or left).