Assertion: middle knuckle | /r/HasProperty | hyperextend
Facets:
Source sentences:
text: Swan's neck deformity occurs when the large knuckle (MCP joint) and the outermost knuckle (DIP) abnormally flex, while the middle knuckle (PIP joint) hyperextends.
text: occurs when the large knuckle (MCP joint) and the outermost knuckle (DIP) abnormally flex, while the middle knuckle (PIP joint) hyperextends.