From A Grammar of English Heraldry, pg. 21
It is unclear what is intended by fig. 67, since “maunch” or “manche” and “sleeve” both refer to the shape displayed on the shield. “Maunche” most likely refers to the sinister part of the sleeve, since it was that portion which differentiated a French “manche” or ordinary sleeve, from the “manche mal taille” displayed here.