lecture #3 major boneiuius(1) (2)

8/10/2019 Lecture #3 Major Boneiuius(1) (2)

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Head and NeckAnatomy

Lecture # 3Sphenoid,

Maxilla and

MandibleChapter 26

Salvador Dali Ballerina 1939


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Sphenoid Bone


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Sphenoid Bone

Single midline bone that articulates with frontal,parietal, ethmoid,temporal, zygomatic, maxillary,palatine, vomer and occipital bones

Runs through the midsaggital section of the skulland helps connect neurocranium toviscerocranium

Resembles a bat with wings Complex bone encountered in almost every view

of the skull


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Sphenoid Bone

Composed ofbody, greaterwings and lesserwings andpaired pterygoidprocesses

Within the bodyis one of thepairs ofparanasalsinuses thesphenoid sinus


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Pterygoid processes

These processes project downwardfrom the body of the sphenoid Articulate with the maxilla (palatine

bones) Projecting down from the medial

pterygoid plate is the hamulus whichis important in attachment of musclesof the soft palate

Muscles of mastication attach tothese plates


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Pterygoid Processes of the SphenoidBone


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=

Lacrimal groove


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Maxilla(e)

Paired bones which join at the midpalatine suture Consists of a body and four processes Frontal process, zygomatic process, alveolar process and palatine process

f

z

a


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Maxilla

10

Body

FrontalProcess

ZygomaticProcess

Alveolar Process

Palatine Process

Courtesy Mike Fey, DDS, MSD

Disarticulatedlateral view withthe body and fourprocesses of themaxilla.


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Palatal process of the maxilla

Incisive foramen


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What is a rapid palatal expansiondevice?

Used to widenthe palate tofacilitateimprovedocclusion

May be fixedor removeable

Usually wornfor 3-4 months


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Maxillary Sinuses

Maxilla containslarge sinuses whichlie within thebodies of themaxillae

Form a very thinwall of bonebetween the rootsof the maxillaryposterior teeth andsinus

Infections mayspread from sinusto teeth and teethto sinus


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What is a sinus lift? (sinus augmentation)

Surgery that adds bone to the maxillaryalveolar process in the region of molars andpremolars to facilitate placement of animplant

Bone may come from your own body(autogenous), from a cadaver (allogeneic) orfrom a cow (xenograft)

The sinus lining membrane is lifted and boneis added


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Paranasal Sinuses


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Paranasal Sinuses There are four pairs of paranasal sinuses two ethmoids, two

frontals, two maxillaries and two sphenoids. The maxillary sinuses are the largest of the paranasal sinuses.

At birth these sinuses are the size of a small pea. With growththey expand to occupy a greater portion of the body of the

maxilla. In a young adult the maxillary sinus occupies an areafrom just posterior to the maxillary canine back to the area ofthe third molar in the anteroposterior direction. In a superiorinferior direction it would extend from the floor of the orbitalcavity inferiorly to the point where it extends down to theroot tips of the maxillary posterior teeth.


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Mandible Single large bone consisting of three parts:

horizontal body, alveolar process and verticalramus

body

ramus

Alveolar process
http://biology.clc.uc.edu/fankhauser/Labs/Anatomy_&_Physiology/A&P201/Skeletal/skull/mandible_lateral_PA281031.JPGhttp://biology.clc.uc.edu/fankhauser/Labs/Anatomy_&_Physiology/A&P201/Skeletal/skull/mandible_lateral_PA281031.JPGhttp://biology.clc.uc.edu/fankhauser/Labs/Anatomy_&_Physiology/A&P201/Skeletal/skull/mandible_lateral_PA281031.JPGhttp://biology.clc.uc.edu/fankhauser/Labs/Anatomy_&_Physiology/A&P201/Skeletal/skull/mandible_lateral_PA281031.JPG


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Lateral view of the mandible


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Lateral view of the mandible The mental protruberance is located at the tip

of the chin. Just posterior to the mentalprotruberance is the mental foramen for thepassage of blood vessels and nerves. The

location of this foramen divides the alveolarprocess from the body of the mandible. Thepoint where the inferior border of the

mandible turns upward is the angle of themandible which divides the horizontal bodyfrom the vertical ramus.


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Midway up the ramus is the mandibular foramen where the nerves and blood vesselsfor the lower teeth and lip enter the mandible. These travel within the mandible in themandibular canal providing nutrition and sensation to the mandibular teeth.

Just anterior to the mandibular foramen is the mylohyoid line an area of attachmentof the mylohyoid muscle.

The mylohyoid groove below the mandibular foramen is for passage of the mylohyoidnerve and vessels to the mylohyoid and anterior digastric muscles.

Toward the anterior part of the mylohyoid line are found the sublingual andsubmandibular fossae. These depressions provide for the salivary glands which are

located in these fossae. The area immediately behind the mandibular third molar is the retromolar triangle.

The lateral margin of this triangle is the external oblique li ne and the medial margin isthe internal oblique line.

At the superior aspect of the ramus of the mandible there are a number of landmarks.

The mandibular condyle articulates with the temporal bone to form the TMJ. Theslightly narrowed area just beneath the condyle is known as the condylar neck.Anterior to the condyle is a depression in the ramus known as the coronoid ormandibular notch. Anterior to the coronoid notch is the coronoid process which is theattachment for one of the muscles of mastication.


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The mandibular canal


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Posterior view of the mandible


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Viewing the mandible from the posterior view of themandible, in the midline are two small, groupedprojections, one above and one below. These arethe superior and inferior genial tubercles or mental spines which provide attachments for muscles thataid in tongue movement and swallowing thegenioglossus and geniohyoid muscles. Just belowthese projections at the inferior border of themandible are the digastric fossae for attachment ofthe digastric muscles.

Also visible is a small projection of bone that partiallycovers the opening of the mandibular foramenknown as the lingula where the sphenomandibularligament attaches.


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Anterior view of the mandible


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Temporomandibular Joint

L t l i f th f h i g


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Lateral view of the face showinglandmarks of the mandible


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Landmarks Ptyergoid processes Hamulus Anterior nasal spine Maxillary tuberosity Median palatine suture Maxillary sinus

Frontal, zygomatic and palatineprocesses and body of the maxilla Mental protruberance Mandibular condyle Coronoid (mandibular) notch Coronoid process Neck of the condyle Body, ramus and alveolar processesof the mandible Angle of the mandible

Mandibular foramen Mental foramen Mandibular canal Mylohyoid line Sublingual and submandibular fossae Retromolar triangle

Genial tubercles (mental spines) Digastric fossa Lingula


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Review / Answer / Read

Review questions: Page 331 (answers page413)

Answer T /F + multiple choice + diagrams:page 516 (answers page 558)

Read Chapter 27 Nose, Nasal Cavity andParanasal Sinuses

Read Chapter 28 Muscles of Mastication,Hyoid Muscles, SCM and Trapezius Muscles fornext class

lecture #3 major boneiuius(1) (2)

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