Anatomical "lines", theoretical lines drawn through structures, are also used to describe anatomical location. For example: * The midaxillary line, a line running vertically down the surface of the body passing through the apex of the axilla (armpit). Parallel are the anterior axillary line, which passes through the anterior axillary skinfold, and the posterior axillary line, which passes through the posterior axillary skinfold. * The mid-clavicular line, a line running vertically down the surface of the body passing through the midpoint of the clavicle. * The mid-pupillary line, a line running vertically down the face through the midpoint of the pupil when looking directly forward. * The mid-inguinal point, a point midway between the anterior superior iliac spine and the pubic symphys