Membrane

Thin layer of tissue covering a surface, lining a body cavity, or dividing a space or organ. Pericarditis is a condition in which the membrane, or sac, around your heart is inflamed.

Meninges, Plural of Meninx

Any membrane; specifically, one of the membranous coverings of the brain and spinal cord. The brain and spinal cord are covered by 3 connective tissue layers collectively called the meninges that consist of the pia mater, the arachnoid and the dura mater. The meninges...

Metastases

The spread of a disease process from one part of the body to another. The appearance of abnormal tissue growths (malignant or nonmalignant) in parts of the body remote from the site of the primary tumor.

Microscopy

Using an operating microscope to better visualize a small operating field or perform delicate surgery. The examination of minute objects by means of a microscope, an instrument which provides an enlarged image of an object not visible with the naked eye.