The human body is a complex organism made up of many parts that need to work together in very specific ways for us to move, think, and do any number of other activities we do every day. One of the body's most critical systems is the musculoskeletal system. Your musculoskeletal system is made up of muscles, bones, tendons, ligaments, and soft tissues that work in tandem to help you move and support your body's weight. Here we're going to look at two critical parts of the musculoskeletal system; ligaments and tendons.
People often confuse ligaments and tendons, but while these two have a few similarities, they also have many distinct properties that differentiate them.
Let's start with the similarities. They are both made up of fibrous connective tissue composed of bundles of collagen fibers, and they both play an essential role in musculoskeletal biomechanics. However, beyond this, the similarities end.
Tendons attach muscle to bone or muscle to structures such as the eyeball. There are around 4000 tendons in the human body. A tendon's primary function is to allow your bones to move as your muscles tighten and relax. You can think of a tendon as a rope - a strong and flexible tissue resistant to tearing. However, while tendons are resistant to tearing, they aren't particularly stretchy, which is why it's possible to stretch a tendon to the point of injury.
But how do tendons work? When you squeeze your muscle, your tendon pulls the bone, causing it to move. The collagenous fibers found in tendons run parallel to each other, allowing the tendon to provide support and more elasticity than in ligaments.
Ligaments connect bone to bone, holding musculoskeletal structures together and keeping them stable. You have ligaments all over your body, including your knees, shoulders, ankles, elbows, and many other places - there are over 900 ligaments in the human body. Here are the primary functions of ligaments:
- Allow the joints to move in the directions they're supposed to.
- Hold your bones together.
- Ensure your joints don't twist, causing injury.
- Stabilize the bones.
- Prevent bones from dislocating.
You can injure a ligament when it stretches too much or moves in the wrong direction. This usually happens as a result of a sudden twist or fall.
In terms of structure, while fibers in tendons run parallel, the fibrous tissue in ligaments forms more of a crisscross pattern, offering stability and strength and some limited flexibility.
The name "ligament" is actually derived from the Latin word for "bind" or "tie" - "ligare". While the simplest way to describe a ligament is to say they "connect bone to bone," there are a few exceptions to this. For example, some ligaments aren't connected to the bone but rather help ensure that internal organs are held in the correct position. An example of this is the womb, which is kept in place by the pelvic ligaments. The main thing to remember is that ligaments provide stability in the body.
Although tendons are more elastic than ligaments, they can still be damaged by overstretching. In some cases, the tendon might slip from its normal position, causing damage. This is called a subluxation. Common tendon injuries include the Achilles (attaches the calf to the heel bone and is the longest tendon in the body), hamstring, and shoulder.
Overstretched or torn ligaments are called sprains and typically happen when a sharp impact or violent twist causes the ligament to hyperextend. Since ligaments have limited ability to stretch, this type of force causes tears. The most common types of ligament injuries are ankle, knee, and wrist sprains.