erector

Also from Answers.com... Chemotherapy Learn what to expect, and what can be done to improve the experience.

1. One that erects: an erector of skyscrapers.
2. A muscle that causes or maintains the erection of a body part.

noun

A person or business that makes or builds something: assembler, builder, constructor, maker, manufacturer, producer. See make/unmake.

A muscle that makes a body part erect. Also called arrector.

[L.] a structure that erects, as a muscle that holds up or raises a part.