Chinsanli or (front "leg three miles") or Qiansanli or LI10 is located in the groove between the extensor carpi radialis muscle and the common digital extensor muscle, one third the distance down from the elbow joint to the radio-carpal joint, and just anterior to the radius bone.

Insertion is to 2 Tsun.
My Graphic
In practice, one needs to become familiar with some of the structures of the elbow region.

(1) Palpate the
olecranon of the ulna at the posterior aspect of the elbow.

(2) Palpate the
lateral tuberosity of the radius

(3) Identify the
groove between ulnaris lateralis mm and common digital extensor mm.

(4) Identify the
groove between common digital extensor mm and the extensor carpi radialis mm.

Once you are familiar with the above structures it is an easy matter to make the measurement to identify Chinsanli which is just anterior to the shaft of the radius.

Insertion is up to 2 Tsun directly into the groove.

My Graphic