In anatomy, a medullary ray (Ferrein's pyramid) is the middle part of a
cortical lobule (or renal lobule). Each consists of a group of
nephrons in the
renal cortex
The renal cortex is the outer portion of the kidney between the renal capsule and the renal medulla. In the adult, it forms a continuous smooth outer zone with a number of projections ( cortical columns) that extend down between the pyramids. I ...
.
Their name is potentially misleading, as "medullary" refers to their destination, not their location. They travel perpendicular to the capsule, and extend from the cortex to the medulla. They may be visualised during
urography.
Additional Images
File:Slide2iii.JPG, Medullary rays
File:Slide23iii.JPG, Medullary rays
References
External links
* — "Urinary System: kidney, H&E, cortex and medullary ray"
* — "Urinary System: neonatal kidney"
*
{{genitourinary-stub
Kidney anatomy