Thursday, April 20, 2017

The Fascial Slings of the Foot and the Balance of the Arches, Part 2

Part 1 of this post introduced the fascial sling which connects at the plantar portion of the medial arch. It includes the tibialis anterior and peroneus longus muscles. The tibialis posterior can also be included in this sling, and the last post looked at how the tibialis anterior (part of the Stomach sinew channel) and the tibialis posterior (part of the Spleen sinew channel) can function synergistically to lift the medial arch. It was discussed that the healthy T&T function of the Spleen-Stomach can help nourish these muscles and that a drop of the medial arch can be seen as part of the Spleen's holding or lifting function. See the previous post for this discussion.

This post will look at the main part of this fascial sling, the tibialis anterior - peroneus longus. This convergence of the Stomach and Urinary bladder sinew channels has a more agonist-antagonist relationship, and working to balance these muscles/channels is key to proper balance in the arches of the foot.

Fig. 1
The peroneus longus (aka the fibularis longus) attaches from the head and proximal portion of the fibula. It traverses the lateral portion of the fibula, passes posterior to the lateral malleolus, travels just superior to UB-62, and crosses under the cuboid bone in the peroneal canal which is created superiorly by the cuboid sulcus and inferiorly by the long plantar ligament. It reaches the medial cuneiform and base of the 1st metatarsal which is its distal attachment. This is the same attachment site as the tibialis anterior, and they connect to one another through the joint capsules of these bones. When it contracts, the peroneus longus creates plantar flexion at the ankle, which pulls on the lateral arch and everts the foot. When it is overactive, it can contribute to foot overpronation by pulling up on the lateral arch and dropping the medial arch.

Fig. 2: Note the lateral branch of the UB
sinew channel which travels behind the lateral
malleolus. Image is from Deadman's
A Manual of Acupuncture.
The peroneus longus is part of the lateral branch of the Urinary Bladder sinew channel (Fig. 2). This muscle has a very strong fascial connection into the biceps femoris (lateral hamstring). For more on this connection, see this past post. This muscle acts as an antagonist to the tibialis anterior muscle (part of the ST sinew channel), which performs dorsiflexion at the ankle and inverts the foot at the subtalar joint.

Fig. 3
Fig. 4
Many agonist-antagonist muscle imbalances are seen between the Stomach (Earth) and Urinary Bladder (Water) sinew channels. Examples include the quadriceps (ST) - hamstrings (UB) and rectus abdominis (ST) - erector spinae (UB). The relationship between the tibialis anterior (ST) and the peroneus longus (UB) is another example.

When the peroneus longus is locked-short and the tibialis anterior is locked long, the foot will be pulled into eversion (Fig.4). Alternately, when the tibialis anterior is locked-short and the peroneus longus is locked-long, the foot will be pulled into inversion.

Treatment can include needling the most reactive tibialis anterior motor point; ST-36 is often the most reactive, but the extra point lanweixue M-LE-13 is also a motor point. And the peroneus longus MP (approximately 1 cun inferior to the fibular head) can also be needled.

There are some more specific advanced techniques that Matt Callison and I will demonstrate at the Pacific Symposium this coming Fall 2017, involving an acupuncture fascial release that helps pull down the lifted UB sinew channel for foot overpronation. This is a bit tricky to discuss in a blog post, but stay tuned for more information in the future.

The next and final post in this series will follow the sinew channels up to the hip and explore how pelvic imbalances can influence foot overpronation.

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  1. Hi Brian,
    I know you saw a fascia connection between the peroneus longus and the biceps femoris, but I believe that is due to the fact that the shaoyang sinew channel is primarily responsible for stabilizing the leg during taiyang and yang ming activation. This is particularly true during unilateral motions, I.e. swing phase of gait. If you read the Chinese text of the ling shu, for foot taiyang it says:
    The foot taiyang sinew channel starts from the little toe, ascending along the foot, it binds to the (outer) ankle and then slants upward to bind to the knee. One part of the channel goes along the bottom of the outer foot to the lateral malleolus and binds at the heel/zhong 踵. It continues upwards from the posterior heel/gen 跟 and binds to the back of the knee. A [second] part of the channel separates and binds at the lateral aspect of the underside/tread/chuai 踹 of the foot and then ascends to the inner aspect of the back of the knee. From the back of the knee, the [two]branches combine and ascend to bind at the buttocks.
    The foot shaoyang says:
    The foot shaoyang jin starts at the fourth toe, goes up to bind at the lateral malleolus and then continues up along the outer part of the leg to bind with the outer corner of the knee. A part of the channels branches, it divides from the lateral side of the fibula and ascends along the thigh going to the front where it binds with the upper portion of futu (伏菟 crouching rabbit) and to the back where it binds to the sacrum.

    Based on the texts you can see that the peroneals are along shaoyang but have a strong fascia connection to both taiyang and yang ming.

    I love that you're doing this blog and look forward to reading more and talking to you about this amazing stuff.
    (Those translations are mine taken from my jing Jin course)

    1. Thanks for the thoughtful reply, Caroline! I have been back and forth on this myself. Originally, I did put the peroneal muscles with shaoyang. And, I definitely do think they connect with the IT Band which I have as part of the GB sinew channel. Currently, I think that the long toe extensors (extensor digitorum longus and hallucis longus) fit better with the GB sinew channel. I would also include peroneus tertius in this. These are on the same fascial plane as the extensor digitorum brevis distally and ITB proximally. All GB primary channel points would involve these strucures (GB-34, GB 40, for instance). Also, these would be analogous structures to the Sanjiao which I have also as finger and thumb extensors. It is still a work in progress, so I appreciate your comments. I need to think about them for a bit and I will reply more soon.

    2. Interesting. I have the extensor digitorum longus in with yangming. The text says that the yangming channel starts on the middle three toes. There are two branches of the foot yangming, one that maps onto tib anterior and another that attaches near to the head of the fibula, which I believe is the EDL. See this quote: The main part of the channel goes along the tibia and joins at the knee. Another part branches to join with the outside of the fibula and converge (合) with shaoyang.
      I wouldn't worry about the points. There are no 'points' on the sinew channels in the ling shu. Any points that are described are all on the Jing Mai [primary channels]. The needling techniques that were described to treat the sinew channels are needling at the tendon attachments or needling the ashi points using a 'hui ci' technique. There were no primary channel points used. Although the jing mai points are effective in getting qi and blood to move in the area, so I use those as well.
      The sanjiao channel and the GB channel parallel each other in a number of ways. One interesting thing I have noticed is the interosseous membrane. The ability for shaoyang 'to pivot' depends on clear mobility between the tibia and fibula in the leg and the radius and ulna in the wrist. In thinking about how to attribute which fascial structures go with which sinew channel you have to consider [at least, this is what I did] first the text itself, then what we know about the 6 confirmation theory [open,close,pivot] and find consistency in function of the fascial chain itself between both the arm and leg channels.

    3. Hi again. I originally had the long toe extensors along with tibialis anterior with yangming, but have shifted them to shaoyang (tib. anterior I still have as yangming). I interpret the beginning of yangming as the dorsal interossei muscles. I agree that the lingshu does not indicate any points for the sinew channels. However, I think the primary channel points can offer clues as to which structures are involved in the sinew channels. For instance, many primary channel points are also motor points (ST-36 is the tibialis anterior motor point, for instance). Trigger points tend to form at the greatest concentration of motor end plates and motor points are, by definition, the region in the muscle of the greatest concentration of motor end plates. Therefore, ST-36 is a frequent ashi point and I think it being a ST channel points adds some merit to tib. anterior being with yangming. Tibialis anterior also matches the description in the lingshu, so that is of course important, also.

      It seems to me that the sinew channels were not developed much after the lingshu, at least in the written literature. The primary channels were much more fully realized. I think some of the primary channel information might fit well into the sinew channels. One example is the clavicular head of the SCM. I have this as part of the sanjiao sinew channel. TrPs in this muscle can be a contributor of headaches, but can also refer into the ear and cause pain and can cause positional vertigo. If I am correct that this is part of shaoyang, it is interesting to consider how points such as SJ-5 can treat headaches, dizziness, and ear problems. Might its effectiveness have to do with a normalization of tension within the clavicular head of the SCM? Also, SJ-16, depending on angle of palpation and needling, would be a frequent ashi point. For me, this supports my thought of it being part of the sanjiao sinew channel.

      I, too, have thought about the relationship of the shaoyang with the interosseus membranes and have consider the pivoting nature. All of the muscles I list in the forearm and leg for shaoyang and for jueyin attach to the interosseus membrane with the exception of pronator teres and pronator quadratus (which would have an indirect impact on the membrane). Also, these shaoyang-jueyin muscles would be able to communicate proprioceptively with one another through the interosseus membrane to coordinate movement. This, by the way, is one of the reasons I started moving away from the peroneals being with shaoyang, as they do not have much impact on the interosseus membrane.

      Thanks again for the discussion. I really enjoy this and would like to do more. I may be less responsive in the next couple weeks as I am preparing my notes for SMAC which will be starting its first round of classes in San Diego for the next certification cycle. But, let's talk more soon. Maybe we can coordinate on a post sometime soon.

  2. That would be great! I think a dialogue that lays out why we each have our own perspective could be very informative to others and a great opportunity to learn from each other. I don't have much of a trigger point background, so it's interesting to hear your take. Also, I like the idea that later evolutions of the primary channel points may have gained actions due to their overlapping on sinew channels. In the Neijing, location of a 'xue' or point was described as finding an opening or space versus a trigger point or congested area. But that could have changed over time as the sinew channels were possibly being conflated with primary channels.
    Hope the class goes well! Caroline

  3. Whenever you are want to talk more you are welcome to email me:

  4. Great article and great conversation.
    I think it would be interesting to do tests on cadavers with needles like the one you did to determine whether peroneus longus was part of Gb or Ub.
    In school we treat sinew channels with Jing points, then meeting points if we don't want problem to go there, and sometimes with Liv1, Gb34 or Du20.