What is the purpose of the navel in the human body, beyond birth?

As Lou Davis says, there is no function of the navel for autonomic function past birth. But it can be argued that there is a musculoskeletal / myofascial function to the navel as it relates to deeper muscular and connective tissue structures in relation to anatomical development and subsequent physiological functional capacity.

The navel is a connective tissue (fascia) locus[1] that is centered around our physical center of gravity, which is why physiotherapists make such a fuss about “core” strengthening. The abdominal muscles and associated connective tissue (including in the area of the navel) constitute a center of support for the viscera and the musculoskeletal (including Lumbar) structures surrounding and supporting it.

This becomes important, in physiotherapy, when the “core abdominal support” has been anatomically or physiologically / functionally compromised. The navel itself doesn’t have muscular components, such as contractive sarcomeres, but it affects the sarcomeres of the surrounding myofascia, including rectus abdominus and external obliques,etc. The navel itself is not the issue, but its location at our center of gravity and the functionality that extends from that center of gravity is the issue.

[1] Fascia: The Tensional Network Of the Human Body; 2012, Elsevier; Robert Schleip, Thomas Findley, Leon Chaitow, Peter Huijing; pgs. 50-52

What does where the pain lies tell you about the nature of a headache?

Most headaches around the eyes, cheeks, temples, and top, back or base of the skull involve the muscles, connective tissue (myofascia), nerves or structures around the joints of the jaw, ear, and/or sinuses. These headaches can be primarily caused by a direct strain or sprain, or secondarily caused by drug side effects or other conditions that precipitate inflammation in those areas. The brain tissue itself does not have nerve endings that perceive pain, but the tissue surrounding it certainly does!

There are many muscles in the neck and head. I’ll primarily address the myofascial pain pattern of each one, since their are too many related conditions and drug effects to list in a single answer. In any case, a thorough examination by a physician to determine the cause of the pain would still be called for.Areas of pain in muscles (from Travell and Simons’ Myofascial Pain and Dysfunction, volume I) are grouped into the following areas:

Varieties of headache (from Travell and Simons' "Myofascial Pain and Dysfunction," volume I)

(Ch.5, pg.167)

The muscles that create the referred pain in these areas are grouped here, in the same text:

Travell and Simons' "Myofascial Pain and Dysfunction," volume I

If you are curious about the specific pain pattern of a particular muscle, you can visit this site (or other similar accredited sites) to find out: National Association of Myofascial Trigger Point Therapists.

For the temporalis muscle, a sample pattern might look like this:

Temporalis muscle

Muscles of the neck can refer pain locally or up into areas of the head, including the face and jaw. Most facial muscles (including muscles of the eye, ear and jaw) tend to refer pain very locally; they very rarely refer down to the neck.

Pain in the face and jaw, especially, tend to indicate problems with the sinuses, eyes, muscles of mastication (chewing), dental problems (such as malocclusion or infection), or some other local infection (such as a cold or flu). Pain can be triggered by any recurrent infection or source of inflammation, even cancer. This essentially means that therapy for the muscles may provide temporary relief, but since the primary trigger has not been resolved, it will keep recurring.

If the problem is primarily myofascial, correction of any source of mechanical strain (including postural or ergonomic strain) must be removed or at least reduced for the therapy to be effective and lasting.  

The first 3 books on this list are my favorites on non-migraine headaches for the layperson: Amazon.com: trigger points and headache: Books

BUT, of course, if a headache is especially severe, has lasted for longer than three days, happens repeatedly, is interfering with your functioning significantly, is affecting your eyesight, hearing, balance, cognitive function, or is doing anything other than just making your head hurt, please go see a doctor right away!

How long does the pain last once you start walking again after foot surgery?

From a reader:

“I fractured my fifth metatarsal and, after attempting to heal naturally for a couple weeks, I ended up getting it fixed surgically, with a titanium plate. Ten weeks after the injury occurred, I finally was able to walk again, using a cam boot and cane. I have no balance issues, but the pain was pretty severe.  I’d say it ranged from 7 or 8/10 at first, and now, a week later, it’s around 5-6.

I’m wondering if you have a sense of when my foot will feel normal again? As in being able to maybe take a jog, or chase my cat?”

My answer:

How long the pain lasts can differ from case to case, but from these descriptions, several ideas come to mind. However, anything I say here is obviously trumped by your podiatrist, who has seen you and directed your care.

You say that you are now at 11 weeks post-op, and you only began mobilizing the foot/ankle last week. My guess is that the area of the heel, where the achilles tendon anchors, has become tight and somewhat adhesed. This creates inflammation in the area. Also, I would bet that the soleus muscle has an active trigger point which needs to be deactivated, and that the muscle needs to be mobilized and rehabilitated.

The reason that I say the soleus muscle, in particular, is that the referral zone for the soleus is nearly unique to that muscle. It looks like this (see TrP1 in the diagram):

Soleus muscle

Keep in mind, 10 weeks (2.5 months, roughly) is a LONG time for your foot to be immobilized. Muscle / connective tissue that has been damaged begins to heal, literally, overnight. Unfortunately, when there is bony tissue fracture or damage that requires immobilization, the soft-tissue takes a backseat to healing the bones completely, which results in the soft-tissue being pretty darned stiff and sore when you begin to re-mobilize.

Here’s what I recommend to those who present with this type of complaint:

  1. Heat the foot and calf with a hot water/epsom salt soak for 10-15 minutes to dilate the blood/lymph vessels and reduce swelling in the joints.
  2. Use a rolling pin (yes, that’s right, like for pastry) to roll across the soleus muscle and compress the trigger point (“X”, above, for TrP1). You can also use the Tiger Tail, a cool new tool I learned about:

Tiger Tail

  1. Use a tennis ball or other compression ball (not too small or hard!) to roll the foot and heel on, to massage it.
  2. Take the foot, ankle and calf through a more challenging series of motions, such as “drawing the alphabet, A-Z” with the foot.
  3. If still sore, either use an ice pack or a lidocaine cream on the heel (only, not the ankle or calf, and please clear with your podiatrist first):


The ice or 4% lidocaine will temporarily deaden the superficial sensory nerves, and hopefully lessen the soreness.

I also recommend walking on a soft surface (such as sand or with your body supported in water) very slowly and barefoot to maximize mobility and minimize impact and weight-bearing to the heel.

Good luck!

Why do we get knots in our back muscles, but not in other areas (e.g. arms or legs)?

Why do we get knots in our back muscles, but not in other areas (e.g. arms or legs)?

“Muscle knots,” otherwise known as trigger points, can occur in any muscle of the body when that muscle is used improperly or damaged. With repeated misuse or damage, the affected sarcomeres (contracting fibers) can “lock” into immobility and inflammation of varying levels. Online research of any skeletal muscle of the body reveals images of trigger point pain patterns for that muscle. (Various muscles associated with locations of pain throughout the body are shown here too: National Association of Myofascial Trigger Point Therapists | Symptom Checker)

Current wisdom on this subject is as follows: “The presence of CGRP (calcitonin gene-related peptide) drives the system to become chronic, potentiating the motor endplate response and potentiating, with SubstanceP, activation of muscle nociceptors. The combination of acidic myofascial pH and proinflammatory mediators at the active trigger point contributes to segmental spread of nociceptive input into the dorsal horn of the spinal cord and leads to the activation of multiple receptive fields. Neuroplastic changes in dorsal horn neurons occur in response to constant nociceptive barrage, causing further activation of neighboring and regional dorsal horn neurons that now have lowered thresholds. This results in the observed phenomena of hypersensitivity, allodynia, and referred pain that is characteristic of the active myofascial trigger point.” 1

To put it in simpler clinical terms, an active trigger point that is referring pain will activate (as a result of tissue metabolism and biochemistry altering the nociceptive threshold) associated soft tissue and neural regions through neuroplasticity.

1. An expansion of Simons’ integrated hypothesis of trigger point formation (pg. 474, 1st P.)

When you’re injured and something is swollen, why is it good to ice it?

When you’re injured and something is swollen, why is it good to ice it?

Your body’s soft tissue includes muscle, fascia (connective tissue), nerves, blood vessels, and lymph vessels, predominantly. When this soft tissue is injured (via bruise, tear, sprain, etc.), it is like a bunch of broken fluid pipes that require the “pressure” to be turned off until the pipe can heal enough to resume stable and reliable function. To reduce this pressure, short, local applications of cold are called for.

The effects this has on the injured joints, bursae, or fascia include:

  • vasoconstriction of blood and lymph vessels, which squeezes out excess plasma and lymph from the site of damage and helps control hemorrhage and hyper-edema (excessive swelling), and
  • brief analgesia, or relief from pain, which may help moderate the inflammatory response from excessive to helpful.

What we’re going for here is modulation of the inflammatory response from over-reactive to measured. This allows the tissue to begin healing in the most helpful bio-environment possible. When applied properly, cold will accelerate the healing rate via beneficial tissue metabolic activity and enhanced return to comfortable function.

1. Hydrotherapy; Theory and Technique, 3d Edition; Patrick Barron; Pine Island Publishers, 2003; pg 72

What can cause muscles to be sore for weeks to the point that they're painful when used?

What can cause muscles to be sore for weeks to the point that they’re painful when used?

Unfortunately, there are quite a few diagnoses that are relevant to muscle soreness and weakness beyond a week’s span. Be sure to have a physician examine you to at least rule out some of the more basic physiological diseases.

Once those are cleared satisfactorily, ask yourself the following questions:

  1. Was there a precipitating event? That is, did it happen all of a sudden? If so, how?

  2. Where in the body did the pain originate? What was the quality of the pain (sharp/burning/dull & aching/sore/tingling/numbness)?

  3. How long did the pain last?

If the pain began with a precipitating event (e.g. “I lifted something;” “I slept funny;” “I twisted in the shower;” “I leapt to catch a ball;” etc.), it usually indicates a sprain or strain to muscle, tendon, or ligament. If you hear a “pop” or “crack” in a joint, it is most likely a connective tissue rupture. If this is the case, you will need a good interview by a sports medicine physician (MD/DO) and probably a scan of some kind (x-ray or CAT scan for bony/cartilage tissues; MRI for muscle/tendon/ligament tissues). This will help to determine what damage, if any, has been done, and if the issue warrants surgery and/or therapeutic intervention. This needs to be your first port-of-call for pain lasting longer than 1-2 weeks.

Once you have determined that there is minimal damage, and therefore, that surgery is unwarranted, you can determine that the cause is one of the following:

  1. Not normal delayed onset muscle soreness (lasting 24-72 hours): See my answer to What causes delayed onset muscle soreness?

  2. A sprain or strain: See Sprains, Strains and Other Soft-Tissue Injuries

  3. If there are multiple areas around the initial location of pain and injury, you may have developed myofascial pain syndrome: “Myofascial pain syndrome typically occurs after a muscle has been contracted repetitively. This can be caused by repetitive motions used in jobs or hobbies or by stress-related muscle tension. While nearly everyone has experienced muscle tension pain, the discomfort associated with myofascial pain syndrome persists or worsens.”

Myofascial pain syndrome (Mayo Clinic)

As a bit of an aside, sub-acute (1-6 months) and chronic (more than 6 months) of myofascial pain are treated thus:

“A successful treatment protocol relies on identifying trigger points, resolving them and, if all trigger points have been deactivated, elongating the structures affected along their natural range of motion and length. In the case of muscles, which is where most treatment occurs, this involves stretching the muscle using combinations of passive, active, active isolated (AIS), muscle energy techniques (MET), and proprioceptive neuromuscular facilitation (PNF) stretching to be effective. Fascia surrounding muscles should also be treated, possibly with myofascial release, to elongate and resolve strain patterns, otherwise muscles will simply be returned to positions where trigger points are likely to re-develop.

The results of manual therapy are related to the skill level of the therapist. If trigger points are pressed too short a time, they may activate or remain active; if pressed too long or hard, they may be irritated or the muscle may be bruised, resulting in pain in the area treated. This bruising may last for a 1–3 days after treatment, and may feel like, but is not similar to, delayed onset muscle soreness (DOMS), the pain felt days after overexerting muscles. Pain is also common after a massage if the practitioner uses pressure on unnoticed latent or active trigger points, or is not skilled in myofascial trigger point therapy.” (Wiki: Trigger point)

(PS – I’m really proud of the Wiki on this. They nailed it, spot on.)

In a standard clinical interview, you have to go over all the aforementioned patient history, physicians’ reports, scans and anything else you can tell or show the practitioner about what may be the cause of the pain. Your practitioner can then figure out what muscles do the motion that produced the injury & other perpetuating factors, which allows the practitioner to decide what to treat first. This is the general clinical starting point for therapeutic focus.