The thinning out of the cervix that normally occurs along with dilation shortly before delivery is called cervical effacement. This is what your doctor was checking for. The fact that your cervix remains closed and you are only slightly effaced are good signs. If you were significantly effaced and beginning to dilate, then you would be at increased risk of a premature delivery. It sounds as if things  are progressing normally and your doctor is taking all the usual steps to make sure that you and your baby stay healthy.  He may want to see you a little more frequently now that you are past your seventh month.  :-)

" Effacement: Thinning of the cervix. Usually in the last month the cervix begins to stretch and thin. This process means the lower segment of the uterus is getting ready for delivery. A thin cervix will also allow the cervix to dilate more easily. Your health care provider may check for effacement in the final 2 months of pregnancy. Effacement is measured in percentages. You may hear your helath care provider say,“You are 25% effaced, 50% effaced, 75%...” The Braxton Hicks contractions or “practice contractions” you have been experiencing may play a part in the effacement process. You will not be able to determine your effacement process, this can only be done by a health care provider's exam. 

 Dilation: Opening of the cervix. Dilation is the process of the cervix opening in preparation for childbirth. Dilation is measured in centimeters or, less accurately, in “fingers” during an internal (manual) pelvic exam. “Fully dilated” means you're at 10 centimeters and are ready to give birth. In the same way that your health care provider may be checking for effacement in the last 2 months, your health care provider may also tell you how many centimeters your cervix has dilated. "(from http://www.americanpregnancy.org/labornbirth/signsoflabor.html)