No, muscles can't push! They can only pull.
http://www.eslteachersboard.com/cgi-bin/motivation/index.pl?page=5;read=356
During dumbbell push-ups, the muscles primarily worked are the chest muscles (pectoralis major), triceps, and shoulder muscles (deltoids).
Push! I think
During a reverse push-up, the muscles primarily worked are the triceps, shoulders, and chest.
The most effective push-up variations for targeting the outer chest muscles are wide-grip push-ups and decline push-ups.
The muscles primarily engaged when performing handstand push-ups are the deltoids (shoulders), triceps (back of the arms), and the upper chest muscles.
The muscles contract which in turn push the baby out.
muscles bend limbs by pulling, they can not push. the answer is; a muscle is a muscle.
The chest and TRiceps
Esophagus
You can pull a muscle which means it really aches but you cant push a muscle
If you pull or push your muscles get stretched and gives discomfort. Sometimes muscle fibres snap in which case you get a lot of discomfort
your eye muscles for squinting your mouth muscles for groaning and your teeth muscles for grinding and your cloud muscles for holding you up.