I also found this:
" The next step was a medical examination to determine physical fitness for service. Each town had its physician for this work. The candidate for admission into the army must first divest himself of all clothing, and his soundness or unsoundness was then decided by causing him to jump, bend over, kick, receive sundry thumps in the chest and back, and such other laying-on of hands as was thought necessary. The teeth had also to be examined, and the eyesight tested, after which, if the candidate passed, he received a certificate to that effect.
His next move was toward a recruiting station. There he would enter, signify his errand, sign the roll of the company or regiment into which he was going, leave his description, including height, complexion, and occupation, and then accompany a guard to the examining surgeon, where he was again subjected to a critical examination as to soundness. Those men who, on deciding to "go to war," went directly to a recruiting office and enlisted, had but this simple examination to pass, the other being then unnecessary.
It is interesting to note that in 1861 and '62 men were mainly examined to establish their fitness for service; in 1863 and '64 the tide had changed, and they were then only anxious to prove their unfitness."
http://www.civilwarhome.com/enlisting.html
Source: " Hard Tack and Coffee or The Unwritten Story of Army Life" (Chapter II, Enlisting) by John D. Billings