![]() The larger of these is the inferior nasal concha, an independent bone of the skull. When looking into the nasal cavity from the front of the skull, two bony plates are seen projecting from each lateral wall. Each side of the nasal cavity is triangular in shape, with a broad inferior space that narrows superiorly. The upper portion of the nasal septum is formed by the perpendicular plate of the ethmoid bone and the lower portion is the vomer bone. Inside the nasal area of the skull, the nasal cavity is divided into halves by the nasal septum. The 22nd bone is the mandible (lower jaw), which is the only moveable bone of the skull.įigure 7.4 Anterior View of Skull An anterior view of the skull shows the bones that form the forehead, orbits (eye sockets), nasal cavity, nasal septum, and upper and lower jaws. In the adult, the skull consists of 22 individual bones, 21 of which are immobile and united into a single unit. The rounded brain case surrounds and protects the brain and houses the middle and inner ear structures. The facial bones underlie the facial structures, form the nasal cavity, enclose the eyeballs, and support the teeth of the upper and lower jaws. It is subdivided into the facial bones and the brain case, or cranial vault ( Figure 7.3). The cranium (skull) is the skeletal structure of the head that supports the face and protects the brain. Identify the bony openings of the skull.Identify the bones and structures that form the nasal septum and nasal conchae, and locate the hyoid bone.Name the bones that make up the walls of the orbit and identify the openings associated with the orbit.Define the paranasal sinuses and identify the location of each.Locate and define the boundaries of the anterior, middle, and posterior cranial fossae, the temporal fossa, and infratemporal fossa.Locate the major suture lines of the skull and name the bones associated with each.List and identify the bones of the brain case and face.The portion above the transverse crest presents behind, the superior vestibular area ( area cribrosa superior), pierced by a series of small openings, for the passage of the nerves to the utricle and the superior and lateral semicircular ducts, and, in front, the facial area (area facians), with one large opening, the commencement of the canal for the facial nerve ( aquæductus Fallopii).By the end of this section, you will be able to: ![]() In the portion beneath the crista falciformis are three sets of foramina one group, just below the posterior part of the crest, situated in the inferior vestibular area (area cribosa media) , consists of several small openings for the nerves to the saccule below and behind this area is the foramen singulare, or opening for the nerve to the posterior semicircular duct in front of and below the first is the tractus spiralis foraminosus, consisting of a number of small spirally arranged openings, which encircle the canalis centralis cochleæ these openings together with this central canal transmit the nerves to the cochlea. Each portion is further subdivided by a vertical ridge into an anterior and a posterior part. It is closed by a vertical plate, which is divided by a horizontal crest, the transverse crest (falcifom crest, crista falciformis), into two unequal portions. The fundus of internal acoustic meatus is the lateral end of the internal aoustic canal.
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