Hyomandibula

The Hyomandibula (Greek y psilon = " the letter Y " because the hyoid bone in humans υ -shaped ( gr ὑοιδἡς ), and Latin. Mandible = " Kinnbacke ", " pine "), even Epihyale, is a skeletal element of the second gill arch ( hyoid or tongue bone arch ) of vertebrates. It is in original vertebrates represents the upper part of the gill arch and is integrated with the skull animals into the jaws of the skull. If there is bony, it says ( os ) hyomandibular.

Hyostylie

About the Hyomandibel exists in most sharks, as well as the genuine bony fish in the form of so-called pine stem an articulation of the jaw to the skull in the area of ​​ear tips ( Hyostylie ), thereby achieving a high mobility of the entire jaw; the jaw apparatus can be lowered independently and back and push. The associated first gill slit is narrowed by this suspension in sharks to the injection hole ( spiracle ). See also fish's mouth.

Ossicles of land vertebrates

Among the land vertebrates ( Tetrapoda ) the hyomandibular was converted to a ossicles. In amphibians, reptiles and birds provides this as a small columns ( columella auris ) is the only ossicles dar. It forms an elongated bone rod and ( columellae base ) with its base in the atrium window ( fenestra vestibuli, also oval window oval window ), a small opening between the middle and inner ear, which has formed as a depression of the contact point of the hyomandibular to the otic capsule, anchored. It serves as a sound- transmitting member between the eardrum and the oval window.

In mammals, two other ossicles with the hammer ( malleus ) and the anvil ( incus ) present, from the upper and lower part of the first branchial arch ( mandibular arch mandibular and palatoquadrate from ) are formed. The hyomandibular here has a stirrup- like shape and is accordingly called the stirrup ( stapes ).

Documents

• Anatomy of the ear
• Bone