The musculature employed in a bassoon embouchure is primarily around the lips, which pressure the reed into the shapes needed for the desired sound. The jaw is raised or lowered to adjust the oral cavity for better reed control, but the jaw muscles are used much less for upward vertical pressure than in single reeds, only being substantially employed in the very high register. However, double reed students often "bite" the reed with these muscles because the control and tone of the labial and other muscles is still developing, but this generally makes the sound sharp and "choked" as it contracts the aperture of the reed and stifles the vibration of its blades.