il age ▁is ▁found ▁between ▁the ▁levels ▁of ▁the ▁C 4 ▁to ▁C 5 ▁verte bra e . ▁ ▁The ▁ob lique ▁line ▁is ▁a ▁line ▁on ▁the ▁thy roid ▁cart il age . ▁It ▁marks ▁the ▁upper ▁later al ▁borders ▁of ▁the ▁thy roid ▁g land . ▁Two ▁mus cles ▁origin ate ▁along ▁the ▁line , ▁the ▁thy ro hy oid ▁mus cle ▁and ▁inferior ▁ph ary n ge al ▁con str ict or . ▁The ▁stern othy roid ▁inser ts ▁along ▁the ▁line . ▁ ▁Mov ement ▁of ▁the ▁cart il age ▁at ▁this ▁joint ▁produces ▁a ▁change ▁in ▁t ension ▁at ▁the ▁vocal ▁fol ds , ▁which ▁in ▁turn ▁produces ▁variation ▁in ▁voice . ▁ ▁Function ▁The ▁thy roid ▁cart il age ▁forms ▁the ▁bulk ▁of ▁the ▁front ▁wall ▁of ▁the ▁l ary nx . ▁It ▁protect s ▁the ▁vocal ▁fol ds ▁(" v ocal ▁c ords "), ▁which ▁are ▁located ▁directly ▁behind ▁it . ▁ ▁When ▁the ▁angle ▁of ▁the ▁thy roid ▁cart il age ▁changes ▁relative ▁to ▁the ▁cr ico id ▁cart il age , ▁this ▁changes ▁the ▁pitch ▁of ▁voice . ▁ ▁The ▁cart il age ▁also ▁serves ▁as ▁an ▁attachment ▁for ▁several ▁mus cles . ▁ ▁Et ym ology ▁ ▁Sh ield - like ▁The ▁English ▁term ▁thy roid ▁cart il age ▁is ▁derived ▁from ▁the ▁Latin ▁expression ▁cart il ago ▁thy re o ides . ▁The ▁latter ▁is ▁a ▁translation ▁of ▁An cient ▁Greek ▁ χ ό ν δ ρ ος ▁ θ υ ρ