The subcutaneous emphysema from swallowing air during vomiting causes a crunching sound, called ____, which is most audible every time the heart beats.

A disease that has an unknown cause or is unique to an individual is called ____

Fill in the blank(s) with correct word

A________ is any instrument that holds open a body cavity to permit inspection.

A. radial keratotomy B. tonometry C. vitrectomy D. speculum