Neuromechanics Weekly: Installment 2 (Now aren’t you lucky to have so much neuro in 1 week!)

FEEL THE PAIN: PART 2

The Character of Pain

In today’s post we hope to help you better understand your pain or the pain that someone else describes to you. The character of the pain can tell you much about what tissues are involved and what might be going on behind the scenes. Understanding the anatomy and physiology of the parts is critical.  Thus, this post is going to be a little latin/medical word heavy for some of you….. but trust us, if you spend just a few extra minutes championing these words and owning the concepts below you will forever be better at what you do. Or at the very least, better understand your own pain.

In prior post in this series we talked about the pain producing tissues being derived from one of the primordial tissues, the endoderm, ectoderm or mesoderm. And if it is from  the mesoderm, from which of the 3 layers of the somite is it originating ? The sclerotome, the dermatome or myotome? (The mesoderm is the middle embryonic germ layer from which connective tissue, muscle, bone, and the urogenital and circulatory systems develop.)

As we discussed yesterday, pain usually has one of four qualities: burning, aching/throbbing, sharp/stabbing, or electric/shooting. Each one tells us something about where it is coming from.

Remember the Krebs cycle? How about glycolysis? What was one of the end products of glycolysis? Lactic acid. Your ability to recycle it and make it into oxaloacetic acid and stuff it back into the Krebs cycle determines your aerobic capacity. When lactic acid builds up, we get muscular inefficiency due to the drop in pH (initially this helps, but too much of a good thing creates a problem), The result? Burning pain. Burning pain is the burn of glycolysis, or muscular overuse.

Aching/ throbbing pain is that deep, boring pain, like a toothache in a bone. It is the pain of the mesoderm, or what is often called sclerotogenous pain. Aching/Throbbing pain is the pain of connective tissue dysfunction (remember that connective tissue is bone, cartilage and collagenous structures like ligaments and tendons). Throbbing pain can sometimes be vascular in origin, as the connective tissue elements of the vessels (the tunica adventitia to be exact) is stretched (which contains a perineural plexus; think about the pain of a migraine headache).

Shooting/electric pain is the pain of the ectoderm. Think about when you hit your ulnar or peroneal nerves and get that “electric shock” sensation. If you ever have had a herniated disc, you know this pain first hand; sharp and shock like. This pain often travels in the distribution of a nerve root or peripheral nerve. 

Sharp/ stabbing pain is the pain of acute tissue damage to one of the 3 layers of the somite (the dermatome, sclerotome or myotome). Think of a sprain (sclerotome) or strain (myotome), or the pain of a shingles outbreak (dermatome). Sharp/stabbing pain is the pain of acute tissue damage.

Keep in mind there is often overlap of pain types, which mean that there is more than one tissue crying out for help (the burning pain in the left hip from gluteus medius insufficiency, combined with the dull, achy pain in the medial knee, from poor control of internal rotation of the thigh).

Pay attention to the character of pain, as it often provides clues to the tissue of origin.

The Gait Guys. Explaining it so you can understand it, one pain free stride length at a time.

Ivo and Shawn