The human body is made up of both hard and soft tissues, which are connected to each other by various attachments. These structures are designed to connect specific parts of the body to one another, and an important example of such attachments are the ligaments.
A specialized band of tough fibrous tissues that connect one bone to another, can be said to be a simple definition of this structure. Ligaments usually have high elasticity, that is, they lengthen and change their shape when they are under tension, and then return to their original shape when the tension is lifted.
However, there are a few exceptions to this rule, like the ovarian ligament, round ligament of uterus and suspensory ligament of the ovary. They connect certain soft tissues to one another. Other exceptions are the peritoneal ligament and fetal remnant ligament. However, as a rule, a ligament denotes the supporting structure connecting one bone to another.
Range of Motion
Ligaments are present in every joint of the body, and are responsible for determining the extent to which the connected joint and/or muscle can extend. Thus, it prevents dislocation of the joint. Also, the ligament-based joint capsule, which is present in most synovial joints, holds the bones together when the joint is flexed or extended.
This limits the extent of movement in the joint, preventing hyperextension of the bones or the joint, by 360 degree rotation or less. Thus, a function of this attachment is to stabilize joints, and guide them during their movement.
Protection of Bones and Joints
Another function is to prevent bones from breaking, or in other words, ligaments prevent bone fractures. When there is any kind of strain on the joint, the ligaments 'creep', i.e., slightly deform under a constant and heavy load.
This prevents joint injury, as ligaments try and act as shock absorbers, and spare the bone of any damage. This is one of the main functions of the anterior longitudinal ligament, which runs down in front of the spine. It prevents shock and impact forces on the back, when there is a sudden change in posture.
One of the most neglected ligament functions is the role played by this structure in maintaining homeostasis and posture of an individual, with the help of proprioception. The tissue types and functions are also closely related.
One good example of this would be seen in the knee joint. Here, the proprioception is provided by a combination of muscles, ligaments, and the receptors involved in this area. When the joint is bent, it is the receptors present in the vicinity that make the muscles contract, while at the same time, makes the person realize the position of his knee and leg.
This is one of the main functions of the anterior cruciate ligament and posterior cruciate ligament, which are important ones that connect the femur to the tibia in the knee area.
Many people tend to confuse ligaments with tendons. However, these are two different structures, which settles the whole ligaments vs. tendons debate, as ligaments help to connect one bone with another, whereas tendons usually connect muscles to bone. Thus, the functions of ligaments and tendons are different.
Ligaments are one of the most common structures to be injured when there is a force that acts on the joint, as can be verified by the common occurrence of a partial ACL tear. Thus, if a person suffers from an injury to the joint, then he should immediately get it evaluated to rule out the possibility of a torn ligament, or any other similar injury.