The "elbow bone" isn't a single bone, but rather the bony prominence you feel on the inside of your elbow is primarily the medial epicondyle of the humerus. Inside this bony structure, you'll find bone marrow and bone tissue, like in any other bone. However, crucially, the ulnar nerve runs behind the medial epicondyle in a groove. This nerve is very close to the surface here, and that's why hitting your "funny bone" (which is actually this nerve) causes a tingling sensation down your arm.
Components Inside the Medial Epicondyle
Like all bones, the medial epicondyle contains:
- Bone Marrow: This is the spongy tissue inside bones that produces blood cells.
- Bone Tissue: This includes both compact (dense outer layer) and spongy (cancellous) bone, providing structural support.
Ulnar Nerve Proximity
The most significant structure near, but not inside, the medial epicondyle is the ulnar nerve. This nerve passes through the cubital tunnel behind the medial epicondyle. While not inside the bone itself, its proximity is crucial to understanding the sensation of hitting your "funny bone."
Why it Matters
Understanding what's near the medial epicondyle is as important as understanding its composition:
- "Funny Bone" Sensation: The ulnar nerve's superficial location explains why a bump to the inside of your elbow can cause a tingling or shocking sensation.
- Cubital Tunnel Syndrome: This condition involves compression or irritation of the ulnar nerve as it passes through the cubital tunnel, leading to numbness, tingling, and weakness in the hand and fingers.
