The Skeleton / What are Ligaments?
submitted by Dr. Gary Farr - Contact the author here. Last Updated September, 26, 2011	Save Money! Check out our special offers here.

What are Ligaments?

Aligament refers to a band of tough, fibrous dense regular connective tissue comprising collagenous fibers. Ligaments connect bones to other bones to form a joint. They do not connect muscles to bones; that is the job of tendons. Some ligaments limit the mobility of articulations, or prevent certain movements altogether.

Internal organs also contain ligaments including the uterus, the bladder, the liver, and the diaphragm.

In the joints, capsular ligaments are part of the articular capsule that surrounds synovial joints. They act as mechanical reinforcements. Extra-capsular ligaments join together and provide joint stability. Intra-capsular ligaments, which are much less common, also provide stability but permit a far larger range of motion. Cruciate ligaments occur in pairs.

Ligaments are viscoelastic meaning they gradually lengthen when under tension, and return to their original shape when the tension is removed. However, they cannot retain their original shape when stretched past a certain point or for a prolonged period of time. This is one reason why dislocated joints must be set as quickly as possible: if the ligaments lengthen too much, then the joint will be weakened, becoming prone to future dislocations. Athletes, gymnasts, dancers, and martial artists perform stretching exercises to lengthen their ligaments, making their joints more supple.

The word ligament comes from the latin word, ligâre, which means "to bind."

In joints, there are two types: capsular and noncapsular.

• Capsular ligaments are simply thickenings of the fibrous capsule itself, taking the form of either elongated bands or triangles the fibers of which radiate from a small area of one articulating bone to a line upon its mating fellow. The iliofemoral ligament of the hip joint is an example of a triangular ligament. Capsular ligaments are found on the outer surface of the capsule. There is one exception to this rule: ligaments of the shoulder joint (glenohumeral ligaments) are found on the inner surface.
• Noncapsular ligaments are free from the capsule and are of two kinds, internal and external.

The internal type is found in the knee, wrist, and foot. In the knee there are two, both arising from the upper surface of the tibia; each passes to one of the two femoral condyles and lies within the joint cavity surrounded by synovial membrane. They are called cruciate ligaments because they cross each other X-wise. At the wrist most of the articulations of the carpal bones share a common joint cavity, and neighbouring bones are connected sideways by short internal ligaments. The same is true of the tarsal bones that lie in front of the talus and calcaneus.

The external, noncapsular ligaments are of two kinds, proximate and remote. The proximate ligaments pass over at least two joints and are near the capsules of these joints.  They are found only on the outer side of the lower limb. Examples are the outer (fibular) ligament of the knee, which passes from the femur to the upper part of the fibula over both the knee and tibiofibular joints, and the middle part of the outer ligament of the ankle joint, which passes from the lowest part of the fibula to the heel bone. These two ligaments, particularly that passing over the ankle, are especially liable to damage (sprain).

The remote ligaments are so called because they are far from, rather than close to, the joint capsule. A notable example is that of the ligaments that pass between the back parts (spines and laminae) of neighbouring vertebrae in the cervical, thoracic, and lumbar parts of the spinal column. (See figures below).

These are the chief ligaments of the pairs of synovial joints between the vertebrae of these regions.  Unlike most ligaments they contain a high proportion of elastic fibers that assist the spinal column to return to its normal shape after it has been bent forward or sideways.

Contrary to the opinion of earlier anatomists, ligaments are not normally responsible for holding joint surfaces together. This is because a set of collagen fibers, like a string, can exert a reactive force only if stretched and tightened by some tensile stress. Normally the bones at a joint are pressed together (when at rest) by the action of muscles or gravity. An individual ligament can stop a movement that tightens it. Such a movement will loosen the ligaments that would be tightened by the opposite movement. The one exception to this case is the movement that brings a joint into the close-packed position. This movement is brought about by a combination of a swing with a spin of the moving bone.  Experiment shows that the combination of movement screws the articular surfaces firmly together so that they cannot be separated by traction and that the capsule and most of the ligaments are in simultaneous maximal tautness.

To view a detailed listing of the ligaments and joints of the head and neck click here.

To view a detailed listing of the ligaments and joints of the thorax click here.

To view a detailed listing of the ligaments and joints of the upper limb click here.

To view a detailed listing of the ligaments and joints of the lower limb click here.

To view a detailed listing of the ligaments and joints of the abdomen click here.

To view a detailed listing of the ligaments and joints of the pelvis and perineum click here.

To view a detailed listing of all the ligaments and joints of the body click here.

For a limited time you can schedule a to talk with a licensed doctor or clinician regarding your condition. Please complete a preliminary and schedule your consultation NOW!

Use our to find a doctor in your area.