Copyright © 1997-2001 Mammography Specialists Medical Group Inc. All rights reserved

HISTORY:
49 year old for screening.

DIAGNOSIS:
Normal craniocaudal view showing positioning variation.

FINDINGS:
Right and left craniocaudal are compared to right and left
craniocaudal one year later. The nipple-pectoral line (NPL)
measurement initially is 7.1 cm.


Image 1. R,L CC

One year later the NPL measured 7.6 cm.


Image 2. R,L CC One year later

This measurement is made from the skin of the areola
posteriorly to the edge of the film or the pectoralis muscle,
whichever comes first. On the initial craniocaudal, the NPL
would have to be measured to the edge of the film. On the later
craniocaudal it is measured to the pectoralis muscle. This is
because much more of the muscle is included on the later film.

DISCUSSION:
Note that the films show a great deal of the pectoralis muscle on
the craniocaudal view. This can be controlled by the technologist
given that the patient has sufficient pectoralis muscle. More
muscle is visualized if the inframammary fold is included on the
image and the technologist takes advantage of the free mobile
margin of the breast inferolaterally by lifting the breast up and
pulling the tissue forward as compression is being applied. The
breast tissue should be perpendicular to the chest wall with the
nipple in profile.

Obtaining visualization of the pectoralis muscle on the
craniocaudal view is not always possible on every patient.
When measurement of the breast tissue is made on the
craniocaudal view from the nipple to the posterior edge of the
film or pectoralis muscle, it should equal the nipple-pectoral
line measurement on the mediolateral oblique view to within 1 cm.
This assures that all of the breast tissue is optimally seen on
both views. An incidental feature is that the pectoralis muscle
has a somewhat bell shaped configuration on the craniocaudal
view. This is due to the slight anterior bulge of the pectoralis
muscle at its most medial extension.

REFERENCE:
Wentz, Gini. Mammography For The Radiologic Technologist. Positioning. Craniocaudal projection. McGraw-Hill, Inc. 1992; Chapter 7: pp. 48-50.

Submitted by:
Ralph L. Smathers, M.D.
Mammography Specialists Medical Group
Los Gatos, California

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