(pĕ-nŭm'bră )

[L. paene, almost + L. umbra, shadow, shade]

1. Healthy tissue that surrounds an ischemic or infarcted part.
2. A shadow, e.g., around a radiographic image or at the margin of tissue treated with radiation therapy.

ischemic p.The penumbra that surrounds an imfarct core and can be salvaged by prompt restoration of blood flow.

SEE: infarct core.