Your anatomy
A ligament is a short band of tough, fibrous tissue connecting bone to bone (in contrast to tendons, which connect muscle to bone). Ligaments form part of every joint in the body, providing strength and support, allowing for a normal range of movement but preventing the joint from moving in the wrong direction, causing it to become unstable.
In order to fulfil this purpose, ligaments must possess immense mechanical tensile strength – the dense, connective tissue from which they are formed is comprised from a protein known as ‘collagen’ (shown right). The longitudinal arrangement of the collagen fibres within the ligament gives it its strength. A normal ligament consists of 90% Type 1 collagen, 9% Type 3 collagen and 1% fibroblast cells (the cells that produce collagen). Mature collagen tissue (Type 1) has the greatest tensile strength; immature tissue (Type 3) provides far less tensile strength to the ligament.
Ligaments are slightly elastic and can stretch lightly with movement of the joint. Athletes perform stretching exercises which make their joints more supple, and people who are ‘double-jointed’ have very elastic ligaments which allow their joints to stretch and contort further than those of most normal people. If ligaments are put under prolonged tension though they can actually lengthen, which is one reason why a dislocated joint must be returned to its normal position as quickly as possible, to prevent lasting damage to the ligaments.
Image - Copyright Pearson Education
Ligaments also provide proprioceptive input to the brain. Proprioception allows a person to know what position their joints are in without the need to look, helping to enable the complex range of movements and co-ordination required to play sport, for example. This is called functional stability.
Whilst most extra-articular ligaments (outside the joint) can heal themselves (providing that the damaged parts remain in close proximity), intra-articular ligaments can struggle to heal due to exposure to synovial fluids inside the joint. For this reason, where a damaged joint continues to give way after an injury or does not respond to conservative treatments such as physiotherapy or a brace, the ligament may need to be reconstructed.
Whilst many different types of ligaments are found throughout the body, those most susceptible to injury include those found in the knee, ankle and shoulder.
| Knee anatomy Although the knee may look like a simple joint, it is actually one of the more complex joints in the body, as well as the largest. |
| Foot and ankle anatomy The foot and ankle have to be very strong and stable joints to take the strain of the weight placed upon them, enabling you to stand, walk and run without pain. |
| Shoulder anatomy The shoulder is not a single joint, but a complex arrangement of bones, ligaments, muscles and tendons, providing strength and motion to the arm. |
* Images - Copyright Pearson Education
Important: The information and guidance provided here is general in nature and should not be considered as medical advice in any way. You should always seek detailed advice from a qualified medical practitioner.
