Changes

'''Middle Ear'''

'''Middle Ear'''

Lizards have middle and inner ears; the tympanic membrane covers the middle ear cavity which is linked to the pharynx and eustachian tube. In general, the inner boundary of the middle ear cavity has two openings: a round one, covered by a thin membrane, and an oval opening that is uncovered. <br>

Lizards have middle and inner ears; the tympanic membrane covers the middle ear cavity which is linked to the pharynx and eustachian tube. In general, the inner boundary of the middle ear cavity has two openings: a round one, covered by a thin membrane, and an oval opening that is uncovered.

 

The stapes (or stirrup) is a single bone that connects the eardrum to the inner ear; it crosses the middle ear cavity, from the inside of the tympanic membrane, its inner end fitted inside the oval opening. The outer end of the stapes has a cartilage cap which comes into contact with the tympanic membrane. In some reptiles, this cartilage, called the extrastapes, is attached to the quadrate (the primary support of the lower jaw). The upper and lower jaws of lizards contain several bones not found in mammals.

The stapes (or stirrup) is a single bone that connects the eardrum to the inner ear; it crosses the middle ear cavity, from the inside of the tympanic membrane, its inner end fitted inside the oval opening. The outer end of the stapes has a cartilage cap which comes into contact with the tympanic membrane. In some reptiles, this cartilage, called the extrastapes, is attached to the quadrate (the primary support of the lower jaw). The upper and lower jaws of lizards contain several bones not found in mammals.