Inside the knee joint, there are two ligaments that help to hold the thigh and shin bones together, while allowing them to move relative to one another, creating a hinge joint. These ligaments are called the cruciate ligaments - together they form a ‘cross’ shape. The cranial cruciate ligament (CCL) sits at the front of the joint and prevents the shin moving forwards relative to the thigh – this is the equivalent of the anterior cruciate ligament (ACL) in humans. It is this CCL that is particularly prone to damage, with a partial or complete tear resulting in pain and instability of the knee joint. This condition is called cruciate ligament disease, and is more common in certain breeds, including Labradors, West Highland White Terriers, Rottweilers, Golden Retrievers and Boxers.