Today’s lesson in anatomy is the multifidus spinae, an important muscle you may never have heard of. It consists of a number of “fleshy and tendinous fasciculi, which fill up the groove on either side of the spinous processes of the vertebrae…”1. Basically, it’s the part of the deepest muscles underneath your thumbs if you’re giving someone a backrub and you press into the fleshy groove just to the left and right of the spine. For a brief overview, wikipedia is your reference (although I really like my copy of Gray’s1.
The multifidus performs the role of vertebral stabilization. It keeps your spine in line. It also happens to be one of my trunk-muscle achilles heels, if that’s not mixing my metaphoric anatomical references.
The reason for today’s anatomy lesson is simple: This is my first official injury of ironman training! As injuries go it’s pretty minor, but it caused me to alter the training plan. Therefore it counts. I strained the lower bit of my multifidus enough that I can feel it during normal activities (like sitting on my butt at work). Ironically, it hurts less when I’m running then when I’m walking. This might seem strange to you, but it’s a fact that muscles activate in different roles between walking and running; this must be an example of that2.
No worries. It’s already getting better. I’ll let you know how it goes.
1: Henry Gray, F.R.S., Grays Anatomy, 15th Edition, 1901
2: The best example of a muscle having vastly different roles between the walking stride and the running stride is the gluteus medius. During normal activity, the gluteus medius is a hip rotator, but during running its role changes to a pelvic stabilizer. I know this because the gluteus medius is a muscle that usually is severely neglected and underdeveloped in triathletes.