Elsevier Inc. items and derived items © 2007 by Saunders, an imprint of Elsevier Inc. Initial...

Elsevier Inc. items and derived items © 2007 by Saunders, an imprint of Elsevier Inc.

Initial Viewing of the SkullInitial Viewing of the Skull

Illustrated Anatomy of the Head and NeckIllustrated Anatomy of the Head and NeckThird EditionThird Edition

Margaret J. Fehrenbach and Susan W. HerringMargaret J. Fehrenbach and Susan W. HerringElsevier, 2007Elsevier, 2007


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NOTENOTE

It is easier to study the skull by first It is easier to study the skull by first looking looking at its various viewsat its various views: the superior, anterior, : the superior, anterior, lateral, and inferior views. lateral, and inferior views.


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Superior View of the SkullSuperior View of the Skull

When the skull is When the skull is viewed from above, four viewed from above, four cranial bones are cranial bones are visible.visible.

At the front of the skull At the front of the skull is the single frontal is the single frontal bone. bone.

At the sides are the At the sides are the paired parietal bones. paired parietal bones.

At the back of the skull At the back of the skull is the single occipital is the single occipital bone.bone. Figure 3-1


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SUTURES ON SUPERIOR VIEWSUTURES ON SUPERIOR VIEW

The suture extending across The suture extending across the skull, between the frontal the skull, between the frontal and parietal bones, is the and parietal bones, is the coronal suturecoronal suture. .

A second suture, the A second suture, the sagittal suturesagittal suture, extends , extends from the front to the back of from the front to the back of the skull, between the paired the skull, between the paired parietal bones. parietal bones.

The third suture, located The third suture, located between the single occipital between the single occipital bone and the paired parietal bone and the paired parietal bones, is the bones, is the lambdoidal lambdoidal suturesuture. .

Figure 3-2


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Anterior View of the SkullAnterior View of the Skull

When the skull is viewed When the skull is viewed from the front, certain bones from the front, certain bones of the skull (or portions of of the skull (or portions of these bones) are visible.these bones) are visible.

These bones include the These bones include the single frontal, ethmoid, single frontal, ethmoid, vomer, and sphenoid bones vomer, and sphenoid bones and the mandible, and also and the mandible, and also the paired lacrimal, nasal, the paired lacrimal, nasal, inferior nasal conchal, inferior nasal conchal, zygomatic, and maxillary zygomatic, and maxillary bones.bones.

Figure 3-3


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Facial Bones on Anterior ViewFacial Bones on Anterior View

The The facial bonesfacial bones visible on the anterior visible on the anterior view of the skull include view of the skull include the lacrimal bone, nasal the lacrimal bone, nasal bone, vomer, inferior bone, vomer, inferior nasal concha, nasal concha, zygomatic bone, zygomatic bone,

maxilla, and mandible.maxilla, and mandible.

Figure 3-4


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Orbit and Associated StructuresOrbit and Associated Structures The The orbitorbit contains and protects contains and protects

the eyeballs.the eyeballs. The larger The larger orbital wallsorbital walls are are

composed of the orbital plates composed of the orbital plates of the frontal bone (roof or of the frontal bone (roof or superior wall), ethmoid bone superior wall), ethmoid bone (greatest portion of medial wall), (greatest portion of medial wall), and lacrimal bone (at the and lacrimal bone (at the anterior medial corner of the anterior medial corner of the orbit) and the orbital surfaces of orbit) and the orbital surfaces of the maxilla (floor or inferior wall) the maxilla (floor or inferior wall) and zygomatic bone (anterior and zygomatic bone (anterior portion of the lateral wall). portion of the lateral wall).

The orbital surface of the The orbital surface of the greater wing of the sphenoid greater wing of the sphenoid bone is also included (the bone is also included (the posterior portion of the lateral posterior portion of the lateral wall).wall).

Figure 3-5


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Orbit and Associated StructuresOrbit and Associated Structures The The orbital apexorbital apex is is

composed of the lesser wing composed of the lesser wing of the sphenoid bone of the sphenoid bone (forming the base) and the (forming the base) and the palatine bone (a small palatine bone (a small inferior portion). inferior portion).

The opening in the orbital The opening in the orbital apex is the apex is the optic canaloptic canal, , which lies between the two which lies between the two roots of the lesser wing of roots of the lesser wing of the sphenoid bone. the sphenoid bone.

The second cranial or optic The second cranial or optic nerve passes through the nerve passes through the optic canal to reach the optic canal to reach the eyeball. The ophthalmic eyeball. The ophthalmic artery also extends through artery also extends through the canal to reach the eye.the canal to reach the eye.

Figure 3-6


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Orbit and Associated StructuresOrbit and Associated Structures Lateral to the optic canal is Lateral to the optic canal is

the the superior orbital fissuresuperior orbital fissure, , between the greater and between the greater and lesser wings of the sphenoid lesser wings of the sphenoid bone. Like the optic canal, bone. Like the optic canal, the superior orbital fissure the superior orbital fissure connects the orbit with the connects the orbit with the cranial cavity. cranial cavity.

The third cranial or The third cranial or oculomotor nerve, the fourth oculomotor nerve, the fourth cranial or trochlear nerve, cranial or trochlear nerve, the sixth cranial or abducent the sixth cranial or abducent nerve, and the ophthalmic nerve, and the ophthalmic nerve (from the fifth cranial nerve (from the fifth cranial or trigeminal nerve) and vein or trigeminal nerve) and vein travel through this fissure.travel through this fissure. Figure 3-7


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Orbit and Associated StructuresOrbit and Associated Structures The The inferior orbital fissureinferior orbital fissure

can be seen between the can be seen between the greater wing of the sphenoid greater wing of the sphenoid bone and the maxilla. bone and the maxilla.

The inferior orbital fissure The inferior orbital fissure connects the orbit with the connects the orbit with the infratemporal and infratemporal and pterygopalatine fossae. pterygopalatine fossae.

The infraorbital and The infraorbital and zygomatic nerves, branches zygomatic nerves, branches of the maxillary nerve, and of the maxillary nerve, and infraorbital artery enter the infraorbital artery enter the orbit through this fissure. orbit through this fissure. The inferior ophthalmic vein The inferior ophthalmic vein travels through this fissure to travels through this fissure to join the pterygoid plexus of join the pterygoid plexus of veins.veins.

Figure 3-7


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Nasal Cavity and Associated Nasal Cavity and Associated StructuresStructures

The The nasal cavitynasal cavity can also can also be viewed from the anterior be viewed from the anterior aspect.aspect.

The The nasionnasion, a midpoint , a midpoint landmark, is located at the landmark, is located at the junction of the frontal and junction of the frontal and nasal bones. nasal bones.

The anterior opening of the The anterior opening of the nasal cavity, the nasal cavity, the piriform piriform apertureaperture, is large and , is large and triangular. triangular.

The The bridge of the nosebridge of the nose is is formed from the paired nasal formed from the paired nasal bones. The lateral bones. The lateral boundaries of the nasal boundaries of the nasal cavity are formed by the cavity are formed by the maxillae.maxillae.

Figure 3-8


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Each lateral wall of the Each lateral wall of the nasal cavity has three nasal cavity has three projecting structures projecting structures that extend inward from that extend inward from the maxilla, which are the maxilla, which are called the called the nasal nasal conchaeconchae. .

Figure 3-8


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The vertical partition of the The vertical partition of the nasal cavity, the nasal cavity, the nasal nasal septumseptum, divides the nasal , divides the nasal cavity into two portions.cavity into two portions.

Anteriorly, the nasal septum Anteriorly, the nasal septum is formed by both the nasal is formed by both the nasal septal cartilage inferiorly and septal cartilage inferiorly and the perpendicular plate of the perpendicular plate of the ethmoid bone superiorly.the ethmoid bone superiorly.

The posterior portions of the The posterior portions of the nasal septum are formed by nasal septum are formed by the vomer.the vomer.

Figure 3-9


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External Lateral View of the SkullExternal Lateral View of the Skull

When viewed from the side, When viewed from the side, the external skull shows both the external skull shows both cranial bones and facial cranial bones and facial bones. bones.

A division between the A division between the cranial bones and facial cranial bones and facial bones can be reinforced by bones can be reinforced by making an making an imaginary imaginary diagonal linediagonal line that passes that passes downward and backward downward and backward from the supraorbital ridge of from the supraorbital ridge of the frontal bone to the tip of the frontal bone to the tip of the mastoid process of the the mastoid process of the temporal bone.temporal bone.

Figure 3-10


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External Lateral View of the SkullExternal Lateral View of the Skull

On the lateral external On the lateral external surface of the skull are two surface of the skull are two separate parallel ridges or separate parallel ridges or temporal linestemporal lines, crossing , crossing both the frontal and parietal both the frontal and parietal bones.bones.

The superior ridge is the The superior ridge is the superior temporal line. superior temporal line.

The inferior ridge or inferior The inferior ridge or inferior temporal line is the superior temporal line is the superior boundary of the temporal boundary of the temporal fossa and where the fossa and where the temporalis muscle attaches.temporalis muscle attaches.

Figure 3-11


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Cranial Bones on Cranial Bones on External Lateral ViewExternal Lateral View

From the lateral view, From the lateral view, the cranium is easily the cranium is easily seen, which includes seen, which includes the the cranial bonescranial bones: the : the occipital , frontal, occipital , frontal, parietal, temporal, parietal, temporal, sphenoid, and ethmoid sphenoid, and ethmoid bones.bones.

Figure 3-12


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Cranial Bones onCranial Bones onExternal Lateral ViewExternal Lateral View

Also present on the lateral Also present on the lateral view of the cranium are the view of the cranium are the coronal suturecoronal suture, an , an articulation between the articulation between the frontal and parietal bones, frontal and parietal bones, and the and the lambdoidal suturelambdoidal suture, , an articulation between the an articulation between the parietal and occipital bones.parietal and occipital bones.

Also present is the Also present is the squamosal suturesquamosal suture, between , between the temporal and parietal the temporal and parietal bones.bones. Figure 3-12


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Fossae on Fossae on External Lateral ViewExternal Lateral View

The The temporal fossatemporal fossa is is formed by several formed by several bones of the skull and bones of the skull and contains the body of the contains the body of the temporalis muscle. temporalis muscle.

Inferior to the temporal Inferior to the temporal fossa is the fossa is the infratemporal fossa. infratemporal fossa. Deep to the Deep to the infratemporal fossa and infratemporal fossa and harder to see is the harder to see is the pterygopalatine fossa. pterygopalatine fossa.

Figure 3-13


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Zygomatic Arch and TMJ onZygomatic Arch and TMJ onExternal Lateral ViewExternal Lateral View

The The zygomatic archzygomatic arch is is formed by the union of the formed by the union of the broad temporal process of broad temporal process of the zygomatic bone and the the zygomatic bone and the slender zygomatic process slender zygomatic process of the temporal bone. of the temporal bone.

The suture between these The suture between these two bones is the two bones is the temporozygomatic suturetemporozygomatic suture..

The zygomatic arch serves The zygomatic arch serves as the origin for the as the origin for the masseter muscle.masseter muscle.

Figure 3-14


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Zygomatic Arch and TMJ on Zygomatic Arch and TMJ on External Lateral ViewExternal Lateral View

The The temporomandibular temporomandibular jointjoint is a movable is a movable articulation between the articulation between the temporal bone and the temporal bone and the mandible. mandible.

Figure 3-14


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Inferior View of the Inferior View of the External Surface of the SkullExternal Surface of the Skull

Most of the structures of the Most of the structures of the inferior aspect of the skull inferior aspect of the skull surface surface are more easily are more easily viewed on the skull modelviewed on the skull model if the mandible is if the mandible is temporarily removed. temporarily removed.

The maxillary, zygomatic, The maxillary, zygomatic, vomer, temporal, sphenoid, vomer, temporal, sphenoid, occipital, and palatine bones occipital, and palatine bones are visible on this inferior are visible on this inferior view of the skull’s external view of the skull’s external surface.surface.

Figure 3-15


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Hard Palate andHard Palate andAssociated StructuresAssociated Structures

At the anterior portion of At the anterior portion of the skull’s inferior the skull’s inferior aspect is the aspect is the hard hard palatepalate, bordered by the , bordered by the alveolar process of the alveolar process of the maxilla with its maxillary maxilla with its maxillary teeth. teeth.

The hard palate is The hard palate is formed by the two formed by the two palatine processes of palatine processes of the maxillae and the the maxillae and the two horizontal plates of two horizontal plates of the palatine bones.the palatine bones.

Figure 3-16


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Two sutures are present on Two sutures are present on the hard palate. One suture the hard palate. One suture is the is the median palatine median palatine suturesuture, a midline articulation , a midline articulation between the two palatine between the two palatine processes of the maxillae processes of the maxillae anteriorly and the two anteriorly and the two horizontal plates of the horizontal plates of the palatine bones posteriorly.palatine bones posteriorly.

The other suture is the The other suture is the transverse palatine suturetransverse palatine suture, , an articulation between the an articulation between the two palatine processes of two palatine processes of the maxillae and the two the maxillae and the two horizontal plates of the horizontal plates of the palatine bones.palatine bones. Figure 3-16


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The hard palate forms the floor The hard palate forms the floor of the nasal cavity, as well as of the nasal cavity, as well as the roof of the mouth. The the roof of the mouth. The posterior edge of the hard posterior edge of the hard palate forms the inferior border palate forms the inferior border of the of the posterior nasal posterior nasal aperturesapertures or choanae. or choanae.

The superior border of each The superior border of each aperture is formed by the vomer aperture is formed by the vomer and the sphenoid bone. and the sphenoid bone.

The posterior edge of the vomer The posterior edge of the vomer forms the medial border of the forms the medial border of the posterior nasal apertures. The posterior nasal apertures. The posterior nasal apertures are posterior nasal apertures are the posterior openings of the the posterior openings of the nasal cavity.nasal cavity. Figure 3-16


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Near the superior Near the superior border of each posterior border of each posterior nasal aperture is the nasal aperture is the pterygoid canalpterygoid canal..

The pterygoid canal The pterygoid canal extends to open into the extends to open into the pterygopalatine fossa pterygopalatine fossa and carries the and carries the pterygoid nerve and pterygoid nerve and blood vessels.blood vessels.

Figure 3-16


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Middle Portion of theMiddle Portion of theExternal Skull SurfaceExternal Skull Surface

The lateral borders of The lateral borders of the posterior nasal the posterior nasal apertures are formed on apertures are formed on each side by the each side by the pterygoid processpterygoid process of of the sphenoid bone.the sphenoid bone.

Each pterygoid process Each pterygoid process consists of a medial consists of a medial pterygoid plate and a pterygoid plate and a lateral pterygoid plate.lateral pterygoid plate.

Figure 3-17


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Middle Portion of theMiddle Portion of theExternal Skull SurfaceExternal Skull Surface

The depression The depression between the medial and between the medial and lateral plates is called lateral plates is called the the pterygoid fossapterygoid fossa. .

At the inferior portion of At the inferior portion of the medial plate of the the medial plate of the pterygoid process is the pterygoid process is the hamulus.hamulus.

Figure 3-17


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Foramina of theForamina of theExternal Skull SurfaceExternal Skull Surface

The larger anterior oval The larger anterior oval opening on the opening on the sphenoid bone is the sphenoid bone is the foramen ovaleforamen ovale, through , through which the mandibular which the mandibular division of the fifth division of the fifth cranial or trigeminal cranial or trigeminal nerve.nerve.

Figure 3-18


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Foramina of theForamina of theExternal Skull SurfaceExternal Skull Surface

The smaller and more The smaller and more posterior opening is the posterior opening is the foramen spinosumforamen spinosum, , which carries the middle which carries the middle meningeal artery into meningeal artery into the cranial cavity. the cranial cavity.

The foramen spinosum The foramen spinosum receives its name from receives its name from the nearby spine of the the nearby spine of the sphenoid bone, which is sphenoid bone, which is at the posterior at the posterior extremity of the extremity of the sphenoid bone.sphenoid bone. Figure 3-18


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Foramina of the Foramina of the External Skull SurfaceExternal Skull Surface

Also on the external surface Also on the external surface of the skull is the large of the skull is the large foramen lacerumforamen lacerum. .

Posterolateral to the foramen Posterolateral to the foramen lacerum is an opening in the lacerum is an opening in the petrous portion of the petrous portion of the temporal bone, the temporal bone, the carotid carotid canalcanal. .

The carotid canal carries the The carotid canal carries the internal carotid artery and internal carotid artery and

sympathetic carotid plexussympathetic carotid plexus..

Figure 3-18


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A bony projection, the A bony projection, the styloid processstyloid process, is , is visible lateral and visible lateral and posterior to the carotid posterior to the carotid canal. canal.

Immediately posterior to Immediately posterior to the styloid process is the styloid process is the the stylomastoid stylomastoid foramenforamen, an opening , an opening through which the through which the seventh cranial or facial seventh cranial or facial nerve exits from the nerve exits from the skull to the face.skull to the face. Figure 3-18


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The The jugular foramenjugular foramen, just , just medial to the styloid process, medial to the styloid process, is more easily seen if the is more easily seen if the skull model is tilted to one skull model is tilted to one side. side.

The jugular foramen is the The jugular foramen is the opening through which pass opening through which pass the internal jugular vein and the internal jugular vein and three cranial nerves: the three cranial nerves: the ninth cranial (glosso-ninth cranial (glosso-pharyngeal) nerve, tenth pharyngeal) nerve, tenth cranial (vagus) nerve, and cranial (vagus) nerve, and eleventh cranial (accessory) eleventh cranial (accessory) nerve.nerve. Figure 3-18


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The largest opening on The largest opening on the inferior view is the the inferior view is the foramen magnumforamen magnum of of the occipital bone, the occipital bone, through which pass the through which pass the spinal cord, vertebral spinal cord, vertebral arteries, and eleventh arteries, and eleventh cranial or accessory cranial or accessory nerve.nerve.

Figure 3-18


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Superior View of the Superior View of the Internal Surface of the SkullInternal Surface of the Skull

The internal surface of The internal surface of the skull is viewed by the skull is viewed by carefully removing the carefully removing the top half of the skull top half of the skull model.model.

The frontal, ethmoid, The frontal, ethmoid, sphenoid, temporal, sphenoid, temporal, occipital, and parietal occipital, and parietal bones are visible from bones are visible from this view of the internal this view of the internal surface of the skull. surface of the skull.

Figure 3-19

Superior orbital fissure

Foramen lacerum


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Foramina of the Foramina of the Internal Skull SurfaceInternal Skull Surface

Also present are the inside Also present are the inside openings of the optic canal, openings of the optic canal, superior orbital fissure, superior orbital fissure, foramen ovale, foramen foramen ovale, foramen spinosum, carotid canal, spinosum, carotid canal, jugular foramen, and jugular foramen, and foramen magnum.foramen magnum.

The perforated The perforated cribriform cribriform plateplate, with foramina for the , with foramina for the first cranial or olafactory first cranial or olafactory nerve, and the foramen nerve, and the foramen rotundum, for the maxillary rotundum, for the maxillary division of the fifth cranial or division of the fifth cranial or trigeminal nerve, are also trigeminal nerve, are also seen from this view. seen from this view.

Figure 3-19

Foramen lacerum



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Foramina of the Foramina of the Internal Skull SurfaceInternal Skull Surface

Also present are the Also present are the hypoglossal canalhypoglossal canal, for , for the twelfth cranial or the twelfth cranial or hypoglossal nerve, and hypoglossal nerve, and the internal acoustic the internal acoustic meatus, for the seventh meatus, for the seventh cranial or facial nerve cranial or facial nerve and the eighth cranial or and the eighth cranial or vestibulocochlear vestibulocochlear nerve.nerve.

Figure 3-19


Foramen lacerum


37Fig 3-22


38Fig 3-23


39Fig 3-26


40Fig 3-30


41Fig 3-31


42Fig 3-32


43Fig 3-44


44Fig 3-45


45Fig 3-48


46Fig 3-51


47Fig 3-52


48Fig 3-54


49Fig 3-60

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