endotome

noun3

1. •
   A medical instrument consisting of scissors with curved blades and long crossing handles, originally used for decapitating a fetus.

   • MATTEI'S ENDOTOME is a powerful instrument working on a scissors-joint; the shanks are double curved, so that by approximating the handles the curved blades can be brought together — 1867
2. •
   A retractable blade that allows great control over the depth of an incision, used for myotomy and arthrotomy.

   • The endotome is introduced through the left upper quadrant port; the blade advanced out of its sheath in its entirety. — 1993
3. •
   The somite cells that eventually give rise to the endothelium.