I’m not talking about being audacious! I’m talking about the roughly 7 trillion nerves in the human body, though come to think of it, you could describe the nervous system as one audacious mechanism. Nerve roots get their start in the intervertebral foramen (IVF), a place Dr Jeffrey Laitman calls “one of the most sacred places in the body”. What does this impressive sounding set of words mean? Inter is Latin for between, vertebral refers to the vertebrae, and foramen is Latin for opening.
Each of the 33 vertebrae is referenced by a number, which relates to its position in the spine. Recall that there are 7 cervical vertebrae, 12 thoracic, 5 lumbar, 5 or 6 fused sacral and 3 or 4 fused coccygeal. Place your fingers on the back of your neck and gently feel for your backbone. Now run them up to where your backbone meets your skull. That’s where you’ll find C1, which holds up your head and is known as the atlas, named after that famous Greek who held the world upon his shoulders. Turn your head left-right, as if shaking your head to say “no”. C2 is the axis and, combined with C1, provides you with that rotation ability. Now feel for the slightly larger bump roughly in the middle of your neck. That bump is C7, your 7th cervical vertebrae.
Continuing with the tour, your spinal cord stops around L1-L2. Put your hands on either side of your body and slide them to your pelvis, the first strong bones you run into south of your waist. The top of your pelvis forms your iliac crest, and those bones meet around L4-L5. If you run your fingers along your entire backbone, the bone you are feeling is called the spinas process.
Nerves come pouring out of the IVF with a mission to innervate the body, i.e. supply the body with nerves. The nerves are referenced by their root value, the level in the vertebral column at which the nerve is born. Hips are innervated by L3, knees by L4, feet by L5, foot flexors by S1. Several times we were given the analogy of a nerve being like a telephone cable, with fibers inside. The job of the phone cable is to carry information in the form of messages; a nerve has the same job. Nerves are made up of fibers; if a nerve is broken it can likely be reattached, but not always so for the fibers within. As Dr Laitman described them, the fibers are the functional elements of the nerves.
Dr Laitman went on to explain that there are two types of nerves: afferent and efferent. Afferent nerves are sensory nerve fibers that bring signals back to the body from the skin and the gut. Essentially, they tell your body how it is feeling. Efferent nerves are motor nerve fibers that send signals to muscles. These nerves help you initiate movement, and in many cases let you respond to information received from the afferent nerves.
THERE AND BACK AGAIN
Our nervous system is continually monitoring the world inside and outside of our bodies. Nerves provide the feedback mechanism by which we know what is going on internally and externally. At FAMI I was awed to see the internal intricacy of the human body. We are strong, we are complex, we are graceful. We have teeny tiny parts, and massive, large parts.
For an eloquent description of FAMI, I refer you to Breaking the Body Out of the Box, a post by one of the FAMI participants who is also involved in a six-month intensive Advanced Mentor Program at Kinected.
- Southern California Orthopedic Institute – Anatomy of the Spine
- Spine Universe – Spinal Anatomy Animation
- University of Maryland Spine Program – Anatomy of the Spine