Alright. Let's dive into the external anatomy of our kidneys. So, the exterior of the kidney is covered in something called the renal capsule. The renal capsule is basically a thin layer of a collagenous connective tissue. Despite how thin it is, this layer is very tough and vibrant. So if you've ever looked at a kidney in a dissection or in an anatomy photo, that outer layer of the kidney that you're seeing is the renal capsule. It is considered a bit of a protective layer because of how tough and fibrous it can be.
Next up, we have one of the most characteristic features of the kidney which is the renal hilum. The renal hilum is the left that you see on the medial surface of the kidney, and that kind of gives it its characteristic little dip that gives it that kidney bean shape. This is going to be the location where the ureter and the blood vessels can enter and exit our kidney. So if you're looking at our kidney image over here, this kind of very classic characteristic side view of a kidney, this little dip in that surface is the renal hilum. I'll go ahead and label that right now.
Our kidneys are held in place and protected by two additional layers of tissue. First up, we have our renal fascia. Renal fascia, like all fascia that we've seen in the human body, is just going to be a dense collagenous connective tissue that will help to anchor the kidneys to the abdominal wall and hold them in place. We also have the adipose capsule, which is a thick layer of adipose or very fatty tissue. That nice thick adipose capsule is basically going to act as a kind of shock absorber if we have any kind of trauma happening near our kidneys. It's a very nice cushiony protective layer in case we get any kind of injuries near the kidney.
If we look down at our image here, I'm just going to kind of orient you to this one here, on the left because it is a little bit of an odd view if you're not used to it