We saw its emergence into the nasopharynx from the inside in Tape 4. The auditory tube enters the nasopharynx here. The narrowest part of the tube is here, where it emerges from the bone. This is the bony part of the auditory tube, connnecting with the tympanic cavity. To see the auditory tube all the way to the tympanic cavity we'll open it along this line, and remove this part of the bone. Here's the cartilage of the auditory tube. To see the auditory tube, we'll remove the tensor palati, and the lateral pterygoid plate. This one is the tensor palati, passing downward and forward to go round the hamulus.
#OPENING OF AUDITORY TUBE FREE#
This one is the levator palati, passing down above the free border of the superior constrictor. It’s concealed between these two small muscles. This is the superior pharyngeal constrictor. The external auditory meatus, and the tympanic cavity have been exposed, as in the previous dissection. In this deep dissection of the infratemporal region we've removed the zygomatic arch, the mandible, and all the muscles of mastication. To see the auditory tube itself, we’ll go back to a dissected specimen. In this deep dissection of the infratemporal region we've removed. Its medial end projects beneath the mucosa of the nasopharynx. The cartilage of the auditory tube is attached to the base of the skull. Only the lateral third of the auditory tube goes through bone its medial two thirds pass though a partial tube of cartilage that’s represented by this added material. The tunnel is quite short: it starts here, and ends here.
It passes forwards and medially in a narrow tunnel in the bone. The auditory tube, which is where we're going next, begins at this opening at the front of the tympanic cavity. This is the lower part of the tympanic cavity with the three small bones removed. To see into the tympanic cavity we removed more bone here. Here's the bony external meatus, here's the groove for the anulus. To see the tympanic membrane we removed this part of the bone. After taking the mandible out of of the picture, we've been looking up at the underside of the petrous temporal bone from below.
We’ll look at the auditory tube, then come back to the tympanic cavity, but first let’s look at a dry bone specimen to see where we’ve been and where we’re going next. Here in front is the opening for the auditory tube, which connects the tympanic cavity with the nasopharynx. We'll get a much better look at them later. This is the handle of the malleus, this is our first look at the incus, and the stapes. There's more of it back here, and up here, as we'll see. Here we're looking into the lower part of the tympanic cavity.
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