Also called Spirit Bone, Ling Gu is located on the Large Intestine meridian at the junction of the 1st and 2nd metacarpal bones.
This point is used in conjunction with Da Bai (Great White) - 22.04. The line diagram shows you where the point are located.
Now here is the important part: if you want to needle it correctly, you place the patient's hand in this position - "standing" on the Small Intestine Channel with the Ling Gu and Da Bai Points facing up toward the ceiling.
Also have them open up the thumb like their hand is holding a bottle or can. Press your guide tube as close to the junction of the bones at the base of the 1st and 2nd metacarpal bones as you can.