Free muscle anatomy charts can be downloaded online. For example, CNET offers such a download. The software can be used on iOS platform.
Examples of CNET's free muscular system chart software are "Anatomy Atlas Free" and "Visual Anatomy Lite." The former allows for anatomical exploration with visual effects while the latter allows for anatomical 3-D rotational views. A free interactive and comprehensive online muscular system chart that is in 3-D is offered by Anatronica. There are also free, interactive online charts for the skeletal system, the nervous system, the cardiovascular system, the digestive system, the endocrine system, the urinary system, the respiratory system and the reproductive system on Anatronica. Except for the skeletal system chart, which can be downloaded into a computer for free, the rest require a specific payment prior to downloading.