Nope, not talking about new legislation in Colorado and Washington State. Sorry. Talking about joints of the body. I know, there’s nothing more boring than an anatomy lecture. Trust me, I know. I’ve made students sit through hundreds of them.
I used to trick them into having fun on the first day of class. I brought in a piece of Tupperware. Not a bowl or container but an implement with a handle and a narrow rubber end with an oddly shaped crack that ran most of the length of the rubber. I let them look, touch, smell, manipulate. No one ever knew what it was.
So I asked, “Based on the structure, what do you think it’s designed to do?” That’s called applied anatomy. That’s what coaches and athletes do. We call it sport.
Often when I work with coaches they have a poor working knowledge of the structures that allow us to move. We call these joints. (What would movement look like if we hadn’t any joints? Think rusty tin man.) Oh, they may have memorized definitions from the care and prevention portion of the coaching basics course, but no one ever showed them how to apply that stuff. To put it into practice. So sometimes when we talk about the how’s and why’s of stretching or strengthening or the science behind preventing injury, we aren’t speaking the same language. Until someone shows them how to put the pieces together. Especially if a player has an injury or an ailment, coaches should at least know the basics of normal anatomy so they can be part of the team when something goes wrong.
So, what’s in a joint? Well, if you eat poultry you are already an amateur anatomist. Pull out that drumstick and thigh. You’ve seen the gristle at the end of the thigh bone – that’s cartilage. You’ve seen the white tapering substance that attaches the meaty muscle to the bone – that’s tendon. If you’re the curious type, you may have examined further to see strong white “strings” that attach bone to bone – those are ligaments. Don’t eat those. And of course, you know what the bones look like. Yep – Chickens R Us.
So, when we move at a joint, that is, when we bend or straighten a knee or rotate at the shoulder, ankle or hip, these motions are bounded and guided by these connecting structures.
- Bones are the main support structures. Many people are surprised to find out they are very dynamic, living structures. (unlike Halloween skeletons) They are growing, remodeling and have good blood flow. This is why when they are broken, they repair themselves.
- Ligaments are tough, fibrous, bendable “cords” that attach bone to bone and provide stability at the joint. They may be outside the “joint capsule” and form a sort of sleeve that supports like an anatomical brace or they may run inside the joint capsule and stabilize one bone relative to the other as the cruciate ligaments do in the knee. They have poor blood flow and are quite inelastic. This why they heal poorly and, once stretched, tend to be a bit more lax.
- Tendons are supple stands that run from the sheath surrounding a muscle to a point or ridge of attachment on the bone. It is this attachment that allows the contraction of a muscle to pull on and move the bone at a joint. If the bone is held steady, the muscle stretches along the line of the tendon’s pull. This is why proper body position, aligning pull with tendon orientation, is essential for the most effective stretching.
- Cartilage is a tough but flexible tissue. Hyaline cartilage covers the surfaces of the long bones allowing smooth movement at the joint. When this covering gets worn away or damaged, arthritis results. The meniscal discs in the knee joint are highly compressible but resilient fibro-cartilage which provide rigid cushioning for weight-bearing. Cartilage is avascular, that is it has no blood supply of its own, and thus relies on fluid squeezed from the surrounding capsule for nutrients. This is why cartilage heals poorly and why warm up which facilitates lubrication of the joints is essential for joint performance.
So let’s put this into play.
The kid who sprains an ankle tears one or more ligaments. Once the ankle is sprained it will be looser and more prone to future sprains because ligaments tend to remain somewhat stretched out. To decrease risk of future sprains the athlete, once healed, should perform dynamic ankle strength training, to re-develop feel for movement, landing, and change of direction. Bracing or taping is often helpful.
The kid who strains a hamstring has injured multiple fibers in the rear thigh muscle or muscle’s tendon. The muscle must be rested so the injured fibers can heal, otherwise they get tugged along with the rest of the fibers when the muscle is active. (A complete rupture of a tendon is a serious injury generally requiring surgery.) Once healed, the athlete must work to regain strength and flexibility in the muscle which matches that in the other leg.
The kid who tears his meniscus has disrupted the cushioning in his knee joint. The flap of cartilage (or complete tear in a more serious injury) wears on the surfaces of the bones at the joint and, if left unattended, will start the arthritic process. The athlete will need to have the knee assessed to decide whether repair is necessary.
There you have a picture of how a joint works or, in these cases, what happens when it doesn’t. The miracle really is how often and how well it does work. These structures, perfectly designed to fit together like a moving puzzle, slide past one another to offer mobility that is stabilized and cushioned. It’s almost as if one body part “talks” to the other so you can move as you wish. After a while it’s like two good friends who don’t need words.
You tell me. When you watch Messi or Ronaldo or Pele or Mia or Abby or Alex in action, don’t you just say, “they were made to move”? That’s sport. Thank a joint.