Webster's New World Medical Dictionary

colony-stimulating factor
A laboratory-made
agent that is similar to substances in the body that
stimulate the production of blood cells. Abbreviated
CSF. Treatment with CSF can help blood-forming tis-
sue recover from the effects of chemotherapy and
radiation therapy.
colorblindness
The inability to perceive colors
in a normal fashion. The most common forms of
colorblindness are inherited as sex-linked (X-
linked) recessive traits. Females are carriers and
males are affected. As a result, approximately 1 in 8
males is colorblind, compared to fewer than 1 in
100 females. The most common form of color-
blindness is red–green. The second most common
form is blue–yellow. The most severe form of color-
blindness is achromatopsia, the inability to see any
color. Testing for colorblindness is commonly per-
formed along with other types of vision screening.
See also 
monochromatism.
colorectal
Related to the colon and/or rectum.
colorectal cancer
See 
cancer, colon.
colostomy
An artificial exit from the colon cre-
ated to divert waste through a hole in the colon and
through the wall of the abdomen. A colostomy is
commonly performed by severing the colon and
then attaching the end leading to the stomach to the
skin, through the wall of the abdomen. At the exte-
rior opening (stoma), a bag can be attached for
waste removal. The end of the colon that leads to the
rectum is closed off and becomes dormant (known
as a Hartmann colostomy). There are other types of
colostomy procedures. Usually a colostomy is per-
formed because of infection, blockage, cancer, or in
rare instances, severe trauma of the colon.
colostomy, iliac
A colostomy in which the exte-
rior opening (stoma) is located on the lower-left
side of the abdomen.