Bringing Precision to Point Location: Locating the Slope/Flat Points
By David Karchmer, LAc
In order to bring about consistent and successful results with acupuncture therapy, it is essential that the acupuncture points and meridians are located correctly. Each acupoint possesses a specific energetic profile, an energetic signature that endows each point with a unique set of clinical capabilities.
When points are stimulated through the process of needling, moxibustion, magnets, qigong, or any other therapeutic means, the medicinal properties of the point become activated, thus bringing about a systemic healing response.
Generally speaking, successful use of acupuncture therapy requires that a practitioner develop his or her expertise in three distinct areas. First, one must come to understand the foundational theories and principles of Chinese medicine, and commit to memory the curative qualities or therapeutic actions for each of the individual points. Second, a practitioner must develop the ability to skillfully perform the techniques of acupuncture and moxibustion. These two areas are equally important. Without one or the other of these, the understanding of what to do and the skills to actually do it, a practitioner can expect to meet with only marginal clinical success.
There is, however, one other competency upon which the successful administration of acupuncture therapy largely depends - the ability to accurately and consistently locate acupuncture points. A practitioner may possess a deep, comprehensive knowledge of Chinese medicine, but lack the practical skills to successfully activate the functions of the points. Likewise, one may excel in the techniques of acupuncture and moxibustion therapy, yet despite a high level of mastery, achieve only partial success because of faulty point location. To bring about successful results with acupuncture, a high degree of proficiency is therefore required in each of these three areas.
This article is intended to help students and practitioners improve their clinical results by refining their skills in palpating acupuncture points and the physiological landmarks that define them. To get the most out of the concepts presented in this article, I recommend that you use an anatomical atlas as a reference to review the anatomical features being discussed.
One of the best ways to refine your skills in point location is to develop a clear mental map of the structures you are palpating before you start looking for them. When you are able to superimpose your mental mapping of each region's anatomy onto the structures you are feeling, you will achieve a much higher probability of palpating the structures correctly. In other words, familiarize yourself with the anatomy of the points until you are sure that you know what you are looking for before you start looking.
The focus of this article will be a group of points I call the Slope/Flat points. The location of this type of point is defined as being the place where a curvature or sloping structure of a bone meets with a flat structure, or a bony straightaway. No bone is entirely straight or flat. All bones curve, and most have protuberances, prominences, epicondyles, condyloid processes or tuberosities.
The locations of several major acupoints are actually determined by such curvatures in the bones. These types of acupuncture points, which I call the Slope/Flat points, can be found by isolating the exact site where the curvature of a bone (the slope) becomes straight, and the flat surface of a bone begins to curve. The most common example of a Slope/Flat point, and the one that is undoubtedly most familiar, is yinlingquan (SP 9). The most universally taught technique for locating this point is to palpate the medial crest of the tibia, isolating the site where the Flat of the tibia's medial crest gives way to the Slope of the tibial plateau.
While Spleen 9 is the most famous of the Slope/Flat points, it is certainly not the only one. Other commonly used Slope/Flat points include:
Anatomical Elements of the Slope/Flat
Slope: The distal slope of the index finger's metacarpophalangeal joint
Flat: The radial surface of the index proximal phalangeal bone
Slope: The index finger's metacarpophalangeal joint (proximal slope)
Flat: The radio-palmar surface of the second metacarpal bone
Slope: The anterior surface of the tibial tuberosity
Flat: The anterior surface of the tibia's anterior crest
Slope: The distal incline of the first metatarsophalangeal joint
Flat: The medial surface of the big toe's proximal phalangeal bone
Slope: The proximal incline of the first metatarsophalangeal joint
Flat: The medio-plantar surface of the first metatarsal bone
Slope: The medial protrusion of the base of the first metatarsal bone
Flat: The medio-plantar surface of the first metatarsal bone
Slope: The medial condyle of the tibial plateau
Flat: The medial crest of the tibia
Slope: The distal slope of the little finger's metacarpophalangeal joint
Flat: The small finger's proximal phalangeal bone's ulnar surface
Slope: The little finger's metacarpophalangeal joint (proximal incline)
Flat: The latero-palmar surface of the fifth metacarpal bone
Slope: The lateral tuberosity of the fifth metatarsophalangeal joint
Flat: The latero-plantar surface of the fifth metatarsal bone
Slope: The proximal incline of the fifth metatarsophalangeal joint
Flat: The latero-plantar surface of the fifth metatarsal bone
Slope: The distal incline of the fifth metatarsophalangeal joint
Flat: The latero-plantar surface of the proximal interphalangeal bone
Each of these points can be located by palpating the bone and isolating the exact place along its surface where the flat surface of the bone and the curvature join together or meet.
Erjian (LI 2): The Slope of this point is formed by the base of the index finger's proximal phalangeal bone; the Flat is formed by the radial surface of the phalangeal bone. The apex of the Slope is produced by the radial prominence of the second metacarpophalangeal joint. If you hold your palm in front of your face with the radial (index finger) side of the hand facing up, you can clearly see the Slope that is formed by the second metacarpophalangeal joint. To locate erjian, use the tip of the index finger to palpate down the Slope, distally toward the tip of the index finger. Feel for the angular junction formed by the Slope and the Flat of the phalangeal bone.
Sanjian (LI 3): This point has the same Slope as erjian, the radial prominence of the second metacarpophalangeal joint. The Flat for sanjian is the radio-palmar surface of the second metacarpal bone. To locate this point, begin with the pad of your index finger on the prominence of the second metacarpophalangeal joint. Palpating proximally, use the tip of the index finger to bounce (like a pogo stick) or slide down the sloping surface of the bone into the angular hollow created by the junction of the Slope and Flat. The point should be located in the gap between the palmar muscles and the palmar surface of the second metacarpal bone.
Zusanli (ST 36): Most practitioners do not locate ST 36 as a Slope/Flat point. Traditionally, this point is defined as being 3 cun distal to dubi (ST 35), and one finger's breadth lateral to the anterior crest of the tibia. Personally, I never attempt to measure 3 cun distal to the knee joint. Instead, I rely on the Slope/Flat model to calibrate the longitudinal coordinate of this point. The Flat for this point is the surface of the anterior crest of the tibia. The Slope is formed by the tibial tuberosity, which rises anteriorly out of the tibial bone near the knee.
To locate zusanli by this method, place the pads of the index and middle fingers on either side of the anterior crest of the tibia, so that the tibial crest is straddled in-between the two fingers. Then, sliding the fingers up and down the front of the tibia, feel for the change in elevation as you approach the knee joint and pass over the tibial tuberosity. To isolate the exact meeting of the Slope and Flat, it may be necessary to ascend and descend the Slope multiple times. After a few passes, begin to slow the movement down, and narrow the amplitude of your palpation to the area where the Slope and Flat meet, making smaller and smaller movements as you hone in. On most patients, at the exact site where the Slope and Flat merge, the structure of the bone tissue will feel slightly rough or ridged, as if a small chink of bone were chipped out of the tibial crest. Once you can isolate this "chink" in the bone where the Slope and the Flat meet, slide your finger tip one finger's breadth laterally across the surface of the tibialis anterior muscle. With a little bit of practice and exploration, this will become a very natural and reliable way to find this commonly used point.
Dadu (SP 2) and Taibai (SP 3): Similar to the Large Intestine meridian's Slope/Flat points, SP 2 and SP 3 share a common Slope, which is formed by the metatarsophalangeal joint of the big toe. The apex of this Slope is produced by the medial-most prominence of the first metatarsophalangeal joint. The Flat for dadu is comprised by the medial surface of the proximal phalangeal bone of the big toe. For taibai, the Flat is defined by the medio-plantar surface of the first metatarsal bone. Dadu should be located at the junction of the "red and white" skin, while taibai should be located by palpating the gap between the inferior surface of the first metatarsal bone and the flexor hallicus brevis muscle. The pads of the index finger work well to find the general vicinity of the Slope and Flat, but to isolate the exact junction where the acupoint lies, it is probably best to use the tip of the fingernail or feel through the flesh of the index finger and try to palpate with the tip of your interphalangeal bone. In my own practice, I find that this "bone-on-bone" can produce a more acute ability to sense the bony angle formed by the meeting of the Slope/Flat.
Gongsun (SP 4): Another of the most universally used Slope/Flat points, gongsun is probably one of the most commonly mislocated points in all of acupuncture. The Slope of SP 4 is delineated by the medial tuberosity of the first metatarsal bone's base, and the Flat is formed by the medio-plantar surface of the first metatarsal bone. It is helpful to think of the first metatarsal bone as a tiny analog of the tibia, whereby the location of gongsun, in the angle formed by the base of the metatarsal bone, mirrors yinlingquan (SP 9), which is located along the curve of the tibia where the flat surface of the medial crest gives way to the projection of the medial condyle. When SP 4 is conceived as a miniature analog of SP 9, it often helps students to avoid the common mistake of palpating past the base of the metartarsal, and mislocating the point in the gap between the base of the first metatarsal and the first cuneiform bone. Like taibai, SP 4 should be located and needled in the gap that lies between the inferior surface of the first metatarsal and the flexor hallicus brevis muscle.
Qiangu (SI 2) and Houxi (SI 3): The anatomical characteristics of these two points are very similar to the ying-spring and shu-stream points of the Spleen and Large Intestine channels. The Slope for both of these points is marked by the fifth metacarpophalangeal joint. Qiangu is found along the distal incline of the Slope, while houxi will be located along the proximal surface. As for the Flat, the ulnar surface of the little finger's proximal interphalangeal bone provides the Flat for SI 2, while the latero-palmar surface of the fifth metatarsal bone serves as the Flat for SI 3. Qiangu should be located and needled at the junction of the "red and white" skin; houxi should be located and needled in the gap that divides the palmar surface of the fifth metacarpal bone and the flexor muscles of the digiti minimi on the ulnar side of the palm.
Jingu (UB 64): The Slope of jingu is formed by the especially prominent tuberosity of the fifth metatarsal bone. The Flat is defined by the latero-plantar surface of the fifth metatarsal bone. Once the junction of the Slope and Flat has been isolated, using the palpation techniques outlined above, this point should be needled in the gap that lies between the plantar surface of the fifth metatarsal bone and the flexor muscles of the digiti minimi on the lateral side of the sole of the foot.
Shugu (UB 65) and Zutongu (UB 66): As with each of the abovementioned ying-spring/shu-stream pairs, these two points share a common Slope, the fifth metatarsophalangeal joint. Shugu is found by palpating the proximal surface of this incline, while zutongu utilizes the distal surface of the slope. The Flat for the proximal of the two points, UB 65, is defined by the latero-plantar surface of the fifth metatarsal bone, while the Flat for UB 66 is formed by the lateral surface of the little toe's proximal interphalangeal bone. Once again, the most accurate technique for isolating the meeting of the Slope and Flat is to use the tip of the fingernail or to feel with the tip of the distal interphalangeal bone. Try to feel for the bony angle formed by the junction of the Slope and Flat. Zutongu should be located and needled in the gap formed by the plantar surface of the fifth metatarsal bone and the flexor muscles of the digiti minimi on the lateral side of the sole of the foot. Shugu should be located and needled at the junction of the "red and white" skin.
The points that are located by use of the Slope/Flat method are among the most important and commonly used of all the acupuncture points. I hope that using the Slope and Flat method of finding these points will help you to bring precision to your point location and improve your clinical results.