The skeleton - bones, cartilage and ligaments (connective tissue, in general), and joints (essentially where bones come together, whether moveable or not) - makes up about 20% of human body weight.

For the convenience of anatomists, the human skeleton is divided into two sections: 1) the axial skeleton, and 2) the appendicular skeleton. The axial skeleton consists of the skull, the spine (or vertebral column), and what is called the boney thorax (the bones of the chest cavity). The appendicular skeleton is composed of the shoulder and hip girdles, and the limbs.

Rather than dwell on all of the bones of the skeleton, we will concentrate on just these areas: 1) the skull plates, 2) the spinal column, and 3) the shoulder and hip girdles.

This is an appropriate time to introduce you to "George," or is it "Natalia?" It is hard to tell anymore, but it doesn't matter, both of them have given permission for us to use them as models (see Figures 3-1a and 3-1b).

Figure 3-1a   Figure 3-1b

Joints, or articulations (where bones touch), are grouped according to one of two classifications: 1) functional, or 2) structural. Functional classifications are based on the amount of movement possible (named as follows: synarthroses - immovable, amphiarthroses - immovable, and diarthroses - freely moveable; while structural classifications are based on joint composition - fibrous, cartilaginous, and synovial.

Fibrous joints are mostly immovable or slightly moveable, like skull sutures [Skull sutures secure the five "helmet" plates - frontal, parietal, two temporal, and the occipital (see Figure 3-2 ). At birth, these plates are held together by fibrous joints. They are flexible, to allow the skull to enlarge as the brain grows. In adulthood, the sutures ossify, and the "helmet" becomes one large bone.], the connection between the radius and ulna that permits wrist rotation, and the tooth-gum connection - technically, a joint.

Figure 3-2

Synovial joints are the most moveable of all joints, and contain a fluid-filled joint cavity. Synovial fluid is somewhat like egg whites, and its slippery quality makes it an excellent lubricant. Synovial joints are unique in that they contain nerves that primarily monitor "stretch." In addition to lubrication, synovial fluid helps to nourish surrounding cartilage - synovial joints have a good blood supply.

There are six types of synovial joints:

1- Plain, or "gliding" joints are slightly moveable, like the carpals and tarsals in the wrists and ankles.

2- Hinge joint, like the elbow, works only in one plane.

3- Pivot , like the Axis/Apex (see Figure 3-3), which are the top two vertebrae that allow us to turn our neck to look to the side without turning our entire body; done by virtue of their unique shapes among the vertebrae. The atlas forms a ring, and the underlying axis, with no cushioning disc between them, includes a "pin" (the "dens") which projects up through the atlas; thereby providing the rotational mechanism that allows the head to rotate independent of the trunk.

Figure 3-3

5- Saddle joint - the thumb is the only example that I know.

6- Ball-and-socket joints, like the shoulders (see Figure 3-4) and hips, are the most mobile in the body, but at a cost of being relatively fragile (unstable). The head of the humerus is lashed into a shallow depression in the scapula (the Glenoid Fossa), which is the source of both the high degree of mobility, and the vulnerability. The hip joint, on the other hand, is very stable, and mobile; but less so than the shoulder. The head of the femur fits into a deep socket (the acetabulum) that is the source of the stability of this joint, while still allowing mobility.

Figure 3-4

Figure 3-5

Next come the 12 thoracic vertebrae; normally structured in the form of a slight backward curve, and identified as T1 to T12.

Then come the five lumbar vertebrae, L1 to L5, which give many of us so many lower back aches and pains. The slight inward curve should be maintained, but an excessive curve (swayback, or lordosis) decreases the structural integrity of the spine. And, of course, that is true of all spinal curvature, including scoliosis , a sometimes disabling lateral curvature.

And, finally, the five sacral vertebrae (usually just one bone in adults - more ossification/fusion) - ending with the coccyx.

Before leaving the exciting world of the vertebral column, inter-vertebral discs (see Figure 3-6) must be mentioned. These discs consist of a tough, fibrous outer material (annulus fibroses), surrounding a soft inner core (nucleus pulposa), and are located between the moveable discs, from C2 to the sacrum. They form a cushion between vertebrae. They contain an extensive amount of water, and the aging process causes some dehydration; which is why it is typical for people to lose height as they age. Also the disc shown displays a bulge (which can result from a variety of causes, which impinges on a spinal nerve. The bulge can become a rupture by completely breaking through the annulus.

Figure 3-6

Fitness Tips

1. Upper/Lower Ab Training?
   
2. Reverse Crunch - Form?
   
3. Omega-3 Fatty Acids
   
4. Grapefruit Juice and Meds
   
5. Free Radical - Antioxidants
   

The answer, from an article by Frederick C. Hatfield and son (International Sports Sciences Association - ABSolutely ABS), is that; indeed, whatever fibers are activated in the rectus abdominus are ON from one end to the other. It is simply impossible to isolate upper or lower abs. The greater the effort required to crunch or situp (e.g., adding weights), the more activation of all abdominal muscle fibers, including those of the obliques, will occur. Those conclusions are based on electromyographical studies.

The Hatfields recommend full-range exercises as being particularly effective. That is, moving from slight hyperextension to hyperflexion [About 60 degrees; I have seen from other sources. This type exercise is ordinarily done on a slant board or bench, or something like a back hyperextension rack.]

Okay, so we can't isolate upper and lower abs, but I will continue to train and recommend to others to continue training as usual, while recognizing that upper/lower is not isolation training, but simply varying the attack point (i.e., hitting the muscle from different angles). There is some overlap if one does traditional "lower abs obliques - upper abs," but there is no harm in that, and not all three need to be done in each session. At the same time, it is important to note that the traditional approach makes sense (to me, anyway) for beginners. Many people are simply unprepared to do weighted ab, or full-range exercises. Body weight is often more than enough.

Here is a clarification of the Reverse Crunch abdominal exercise. In the past, I and others, have described it more-or-less as follows: on your back, with knees up, heels close to buttocks; pull your knees toward your chest until your hips are raised off the floor. Pause, then slowly return to the starting position. That's one rep. That description leaves room for an error in technique, of which many people have managed to take advantage. The missing piece is that raising the hips is done by the abdominal muscles, not by the momentum of flinging your knees toward your chest. In reality, your thighs move only because your hips move, and they are just along for the ride.

More omega-3 fatty acid information. According to the March 1997 Tufts University Health & Nutrition Letter, there is an ever-increasing body of evidence that supports the need for omega-3 fatty acids, found largely in fatty fish - cold water fish, like herring, Atlantic salmon, or mackerel; and some in vegetable sources - green leafy vegetables, nuts, canola oil, soybean oil, and tofu. And not just for protection against heart disease, but also in lessening the effects of rheumatoid arthritis, lessening premature infant developmental problems, and maybe lessening depression.

It has long been known that eating fish a couple of times a week helped to cut down on deaths from heart disease. It is especially productive for those who have already had a heart attack, or some other coronary problem. It is thought that omega-3 FAs act as a blood thinner. More recently, it seems that they may prevent arrhythmias, as well. And they may even help keep arteries open after angioplasty.

Another area that may be helped by omega-3s is rheumatoid arthritis. They may help ease the pain. Unfortunately supplements may be needed -- food sources alone seem to be ineffective. But DO NOT take fish oil supplements without consulting a physician.

An omega-3 FA called DHA may be an essential ingredient in brain growth in babies, particularly in the last three month's growth before delivery. A baby carried to full term ordinarily gets plenty of DHA from its mother, through the placenta, if carried full term. A premature birth, however, can lead to a deficiency, and retarded brain development. Even after delivery, babies that are breast fed are better off than bottle fed babies - breast milk contains DHA. Adding DHA to formula is under discussion.

On the effects of DHA on depression, there is too little evidence to make a definitive statement.

Here is kind of an interesting finding: grapefruit juice increases the absorption of some drugs - specifically the sedatives: Halcin (Triazolam) and Versed (Midazolam); the anti-hypertensives: Plendil (Felodipine) and Procardia (Nifedipine); and the antihistamine Seldane (Terfenadine); and, finally, the immunosuppressant Sandimmune (Cyclosporine). Don't take any of these meds with grapefruit juice, you could OD.

Let's talk about "free radicals" and "antioxidants." We hear about them all the time now, but what are they?

First, the villain - free radicals . In a nutshell, they are produced by oxidation, a chemical reaction. Oxidation (the free radicals produced) can alter many body substances, or even destroy them. Put another way, free radicals can damage cell structures, and alter cell functions - like create cancer, cataracts, diabetes, and heart disease.

In addition to being created by oxidation, they can also come from the environment - air pollution, cigarette smoke, - even exercise can create free radicals. Metabolic oxidation is stimulated by exercise, resulting in free radicals.

Antioxidants , vitamin C, vitamin E, and beta carotene (a vitamin A precursor) are compounds that protect others from oxidation by being oxidated themselves. They seem to protect against, at least, cancers and heart disease.

Eating lots of fruits and vegetables is recommended, not only for the known antioxidants, but for other, as yet undiscovered, chemicals that act as antioxidants. And there seems to be a synergistic link between the chemicals that makes supplements less effective than food.

In terms of antioxidant power, the stars are: 1- blueberries, 2- kale, 3- strawberries, 4- spinach, 5- Brussels sprouts, 6- plums, 7- broccoli, 8- beets, 9- oranges, 10- red grapes. But the list goes on, including: potatoes, corn, bananas, carrots, pink grapefruit, tomatoes, apples, red bell peppers, and a host of others.

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