Cruciate ligament

Cruciate ligaments (also cruciform ligaments) are pairs of ligaments arranged like a letter X. They occur in several joints of the body, such as the knee joint and the atlanto-axial joint. In a fashion similar to the cords in a toy Jacob's ladder, the crossed ligaments stabilize the joint while allowing a very large range of motion.
Knee.
Structure.
Cruciate ligaments occur in the knee of humans and other bipedal animals and the corresponding stifle of quadrupedal animals, and in the neck, fingers, and foot.
Clinical significance.
Rupture.
Rupture of the anterior cruciate ligament is one of the "most frequent acquired diseases of the stifle joint" in humans, dogs, and cats; direct trauma to the joint is relatively uncommon and age appears to be a major factor.
Cruciate ligament injuries are common in animals, and in 2005 a study estimated that $1.32 billion was spent in the United States in treating the cranial cruciate ligament of dogs.
Etymology.
In the first edition of the official Latin nomenclature ("Nomina Anatomica", renamed in 1998 as "Terminologia Anatomica"), the Latin expression "ligamenta cruciata" was used, similar to the expression "cruciate ligaments" currently in use in English. In classical Latin the verb "cruciare" is derived from "crux", meaning "cross". It became considered that cruciate was equivalent to "cross-shaped".