How are Extensor Tendons Injured?
Extensor tendons are just under the skin, directly on the bone, on the back of the hands and fingers. Because of their location, even a
minor cut can easily injure them. Jamming a finger may cause these thin tendons to rip apart from their attachment to the bone. After this type of injury, you may have a hard time straightening one or more joints. Treatment is necessary to return use to the tendon and finger.
Boutonniere deformity describes the bent-down (flexed) position of the middle joint of the finger
from a cut or tear of the extensor tendon at the middle joint. Sometimes, stitches are necessary when the tendon has been cut and even if the tendon is torn. If the injury is not treated, or if the splint is not worn properly, the finger can quickly become even more bent and finally stiffen in this position.
(This one shows the Boutonniere deformity referenced above)
So JA either cut herself to attain this injury or she jammed her finger.
No break, thus her story is a fake. I am pretty sure that this is a point Juan will revisit before closing.
I believe with some pressure, she can straighten her finger when laying her hand down. jmo