This fact is from Anchorage Types in Orthodontics. It is a commonly tested concept in NEET MDS examinations. Understanding this fact is crucial for answering MCQs correctly.
Nance holding arch = maxillary anchorage
Lingual arch = mandibular anchorage
Headgear = extraoral anchorage cervical pull or high pull
Critical anchorage = ALL space needed for crowding
Maximum anchorage = most space for retraction
Moderate anchorage = reciprocal movement acceptable.