Lines A, B, C, and what now?!
The Master Tung points on the finger (if you're using the number system for Tung points, those are the 11.xx points) can be confusing to find, not because it's all that difficult, but because it's kind of hard to tell from a lot of references what aspect of the finger the points fall on. We don't have language for that in TCM school!
In the Master Tung system, you draw imaginary lines down the length of the finger from the metacarpal joint to the distal tip of the finger. These lines are labeled A through H.
Here's how to find those points.
For any given finger:
A - Line: Radial margin of the finger where the skin changes color (or if you're super white like me, changes texture) is the A side of the finger.
E-Line: Ulnar margin where the skin changes texture/color is the E side.
These are the critical ones to remember. You can figure out the others pretty easily if you know which side to start from and what direction to "count." Using the diagram above and these principles, you could figure that the C line is the palmar side of the finger and goes right down the palmar center of the finger and that the G line is on the dorsum of the finger along the dorsal center line.
Example:
Let's say you want to needle a 2-point set called Fu Ke (an awesome point for just about anything gynecologically related). This set of points is located on the proximal segment of the thumb on the "F" line. Looking at the diagram above you can see that The "F" line of the thumb is between the ulnar margin and the dorsal midline of the thumb.
Using my old-ass hand as an example, those lines would look like this.
Doesn't matter if you're needling the right hand or the left hand, just know that the A line is on the radial side and the E line is on the ulnar side. Count (ok, it's alphabetical, but you know what I mean) around the finger to find the lines you're looking for.