"charnela = hinge; hinged or articulated joint"
http://forum.wordreference.com/showthread.php?t=106568

"Transverse (ac) joints are abundant. They are steep to vertical and trend east-west, essentially perpendicular to the fold axes. These are tension joints; ..."
http://www.planetary.brown.edu/mappers/Fieldtrip_2003/Purgat...

"Layer parallel shear responsible for the asymmetry of the folds caused joint rotation toward the fold hinge within the long limb. ..."
http://www.sav.sk/index.php?lang=sk&charset=&doc=publish-jou...

"As you walk along these ledges, be on the lookout for folds, joints, and quartz veins like those described for the Cape Elizabeth Formation..."
http://maine.gov/doc/nrimc/mgs/explore/bedrock/2-lights/rock...

"Both crystals and irregularly shaped grains of feldspars are commonly twinned. ... of such structural features as faults, joints, cleavage, and small folds. ..."
http://www.britannica.com/EBchecked/topic/145289/Crystal-Mou...