Trembling at the Knees

Genuphobia is an irrational fear of knees; your own, or even someone else's knees. 

Genuphobia (from Latin word genu meaning ‘knee’) is a rare phobia that can be caused by witnessing or experiencing a traumatic knee injury. Alternatively, it might also be caused if you come from a highly conservative religious background where knees are always covered. Some sufferers experience extreme anxiety just thinking about knees, let alone seeing them.