And boom:
"What are the symptoms of a cruciate ligament injury?
[
B]Often, a cruciate ligament injury does not cause pain[/B]. Instead, the person may hear a popping sound as the injury occurs, followed by the leg buckling when trying to stand on it, and swelling. However, each individual may experience symptoms differently.
The symptoms of a cruciate ligament injury may resemble other conditions or medical problems. Always consult your physician for a diagnosis.
How are collateral ligaments injured?
The medial collateral ligament is injured more often than the lateral collateral ligament. Stretch and tear injuries to the collateral ligaments are usually caused by a blow to the outer side of the knee, such as when playing hockey or football."
http://www.nationalsportsmed.com/knee.html
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