Assertion: retrocalcaneal bursa | /r/CapableOf | serve as a both a cushion
Facets:
value: between the achilles tendon
type: LOCATION
value: between the heel bone
type: LOCATION
Source sentences:
text: The retrocalcaneal bursa is a thin, slippery, fluid-filled sac that serves as a both a cushion and lubricant between the heel bone and the Achilles tendon.