Cortical

Having to do with the cortex, the outer portion of an organ.

The outer portion of the adrenal gland is called the adrenal cortical part; the outer portion of the cerebrum is the cerebral cortical area (a key part of the brain responsible for higher cortical functions); the outer part of the kidney is the renal cortical portion (it lies just beneath the capsule surrounding the kidney); etc.

Cortical is in contrast to the inner portion of the organ which is called the medullary portion.

Thus, there is the adrenal medulla; the medulla oblongata of the brain; the renal medulla; etc.

The word 'cortical' comes from 'cortex', Latin for the bark of a tree.