Muscle or Ligament….. What’s the difference?

How often have we heard, or even ourselves said, “I’ve pulled a muscle” or “I’ve torn a ligament”?

But what does that mean?

Those statements and use of words are not that far from the truth.

Let’s examine what these structures are and their purpose.

Both of these structures work in conjunction with the joints throughout the body, ie. elbow, fingers, hip, knees.

The Muscle consists of primarily two parts, the Muscle Belly and the Tendon. The belly of the muscle is the area where the greatest amount of movement takes place within the muscle structure. It is here that the shortening, or contraction, and the lengthening during relaxation takes place.

Flex your elbow, meaning to bring your palm of your hand to your shoulder. Notice how your Biceps seem to appear larger, then as you straighten your arm it almost appears to go away. That is the contraction and relaxation of the muscle belly.

The Tendon is the part of the muscle that acts as an anchor, attaching to the dense tissue covering the bone itself, known as the periostium. This anchor point is known as the teno-periostial junction.

The tendon is on either end of the muscle belly, and where they intersect is referred to as the myo-( latin for muscle )-tendinous junction. This is the most common site for injury within the muscle structure.

So, what does a muscle do?

The muscle “acts” on a joint. In fact, there is no muscle, other than the heart, that doesn’t act on a joint. Meaning, the muscle’s main reason for being is to move, and protect the joint. So, each crosses over the joint it “acts” upon.

Flex your elbow again. The tendon part of the muscle attaching to the forearm acts as anchor bending the elbow as the muscle belly of the biceps contracts.

So, yes, you “pull” a muscle, because that’s what it does.

A Ligament on the other hand, doesn’t contract or move the joint, but acts as a stabilizer or support to the joint.

Ligaments attach one bone to another. The ligament is made of dense tissue that only allows small amounts of movement between the bones that it attaches to.

While the muscle moves the joint within its capability and within a certain Range of Motion, a ligament prevents excessive motion between the two bones that make up the joint it supports.

When one “rolls” their ankle, excessive stress is created on the ligament that supports the bones forming the joint. Because of the lack of contractile capability within the ligament, it stretches or, in severe cases can be “torn”.

Unfortunately a torn or stretched ligament can lead to possible laxity, or instability to the affected joint. This in turn can lead potential of future re-injury to the area.

In conclusion, the muscle structure creates movement of the joint and, in an healthy state, can aid in the support of the ligament. And, a strong, healthy ligament, stabilizing the joint it attaches to, allows for less excursion to be placed on the muscle acting on that joint.