Caudad: Away from the head (towards the feet)

Cephalad: Towards the head.

Chondral: Pertaining to cartilage (as in "chondral lesion". See "lesion" below)

Distal: Away from the center of the body or the top of a limb. The foot is distal to the knee. Opposite of proximal.

Dislocation: The kneecap completely slips out of the groove. The kneecap doesn't spontaneously go back in place.

Dysplasia: Congenital anatomic anomaly featuring incomplete development.

Extension: Straightening

Extensor Mechanism: Quadriceps muscles + patella + related tendons. These "extend", i.e. straighten the knee.

Fibrous: Tough, dense. Like fiber

Flexion: Bending

Inferior: Further down. Similar to "distal".

Instability: A situation whereby the kneecap slips out of its groove. This is uncomfortable and/or painful.

Lateral: Away from the midline of the body.

Lesion: A visible disorder. In the context of this webpage, you will see this word most commonly in conjunction with the word cartilage. Cartilage is a white, smooth substance. Occasionally it will have a crab meat appearance, or it will be worn down, or there will be a bubble-like swelling. All of these changes are lesions.

Medial: Closer to the midline of the body.

Posterior: Towards the back. Opposite of anterior.

Proximal: close to the center of the body or to the top of a limb. The knee is proximal to the foot. Opposite of distal.

Subluxation: The kneecap partially slips out of the trochlear groove.

Superior: Further up. Similar to "proximal".

Symptomatic: Causing symptoms, e.g. pain.