Head & Neck DH: Chapter 3 Skeletal System Objectives

External oblique line

At what bony demarcation does the ramus join the body of the mandible?

Between the greater wing of the sphenoid bone and maxilla, infraorbital and zygomatic nerves, branches of the maxillary nerve, infraorbital artery and the inferior ophthalmic vein

Describe the inferior orbital fissure and its location, as well as what travels through it.

- Lateral to the optic canal is the curved, slit like opening, between the greater and lesser wings of the sphenoid bone - 3rd cranial (oculomotor) nerve, 4th cranial (trochlear) nerve, 6th cranial (abducent) nerve, then the ophthalmic nerve (from the 5th cranial or trigeminal nerve) and vein travel through this fissure.

Describe the superior orbital fissure and its location, as well as what passes through it.

Lateral external surface, 2 separate parallel, crossing both the frontal and parietal bones. Superior ridge is the superior temporal lines and the inferior ridge is the inferior temporal line which is superior boundary of the temporal fossa and where the fan shaped temporalis muscle attaches.

Discuss the temporal lines and where they are located.

Anterior process is the lesser wing of the sphenoid, which comprises of the base of the orbital apex, the posterolateral process is the greater wing of the sphenoid bone and is the pterygoind process, an area of attachment of some muscles of mastication.

Explain the relationship of the processes of the sphenoid bone to each other?

Cranial & facial bones

How are the bones of the skull divided?

Frontonasal duct into the nasal cavity through the middle nasal meatus

How does each frontal sinus communicate with and drain into the nasal cavity and where does it drain?

Into the nasal cavity through an opening superior to each superior nasal concha

How does each sphenoidal sinus communicate with and drain into the nasal cavity and where does it drain?

- Middle of meatus on each side - Ostium of each sinus is higher than the floor of the sinus cavity

How does the maxillary sinus drain and how does the position of the ostium relate to infection?

22 bones

How many bones from the skull of the patient (not counting the small bones of the middle ear)?

In the lateral mass of the ethmoid

In what specific location are the ethmoidal sinuses?

Less dense

Is the facial bone of the upper jaw more or less dense than that of facial bone of the lower jaw?

Single; articulates with the paired parietal, paired temporal, sphenoid bones of the skull and also articulates with the 1st cervical vertebrae (atlas)

Is the occipital bone paired or single and what bones does it articulate with?

Palatal or mandibular tori

Name and further describe normal variation of bone in the orofacial region that involve bony enlargement.

- Incisura/Notch: indentation at the edge of a bone - Sulcus/sulci: shallow depression or groove, usually marks the course of blood vessels or nerves -Fossa/fossae: generally deeper depression, concavity on a bone surface - Plate: flat structure of a bone

Name four types of bony depressions and state which one is considered generally deeper (and also include their plural forms).

Frontal bone, behind the supraorbital ridges

Name the location of the frontal sinuses.

Anterior tubercle, transverse process, superior articular surface of lateral mass for occipital condyle, groove for vertebral artery, transverse foramen, anterior arch, spinous process, dens, superior articular facet for atlas, pedicle

Name the parts of each of the cervical vertebra.

Body of the sphenoid bone

Name the specific part of the bone where the sphenoidal sinuses are located.

- Coronal Sutures: frontal & parietal bone - Frontonasal Suture: frontal & nasal bones - Intermaxillary Suture: maxillae - Lambdoidal Suture: occipatal & parietal bones - Median Palatine Suture: anterior part; maxillae /posterior part: palatine bones -Sagittal Suture: parietal bones - Squamosal Suture: temporal & parietal bones - Temporozygomatic Sutures: temporal bones & zygomatic - Transverse Palatine Suture: maxillae & palatine bones - Zygomaticomaxillary Sutures: zygomatic bones & maxillae

Name the structures of the skull bones and what bones they join.

Ethmoid bone, numerous foramina for the first cranial or olfactory nerve.

State where the cribiform plate is located and what passes through it.

Sphenoid bone carrying the maxillary nerve

State where the foramen rotundum is located and what passes through it.

Occipital bone, 12th cranial hypoglossal nerve

State where the hypoglossal canal is located and what passes through it.

-Medial aspect of the orbit, articulation of the zygomatic bone with bone with both the frontal and temporal bones, articulation of the pterygoid plates, the palatine bones and each maxilla - bone can fracture

What are the buttress points of the skull and what can happen with sever blows to the face?

Paired occipital condyles, articulate with the atlas

What are the curved and smooth paired projections on the occipital bone that are both lateral and anterior to the foramen magnum and also what do they articulate with?

Supraorbital ridges, subadjacent to the eyebrows and more prominent in adult males.

What are the curved elevations over the superior part of the orbit and on what bone are they located and also at what age and in what gender are they more prominent?

Paired hypoglossal canals -- 12th (hypoglossal) nerve passes through them

What are the paired openings in the skull that are anterior and lateral to the foramen magnum on the occipital bones and what passes through them?

- Lateral borders of the posterior nasal apertures are formed on each side by the pterygoid process. - Each process consists of a thin medial pterygoid plate and a flattened lateral pterygoid plate.

What are the processes and plates of the sphenoid bone?

Lateral pterygoid plate, pterygoid fossa, medial pterygoid plate, pterygoid process, foramen ovale, foramen spinosum, spine of the sphenoid bone

What are the seven landmarks on each greater wing of the sphenoid bone?

Genial tubercles or mental spines, muscle attachment area

What are the small midline projections on the internal surface of the mandible and what is their function?

Superior, middle and inferior nasal conchae

What are the three projecting structures that create the lateral walls of the nasal cavity and which extends inward from the maxillae?

Frontal bone articulates with the paired parietal bones, sphenoid bone, paired lacrimal bones, paired nasal bones, ethmoid bone, paired zygomatic bones and the paired maxillae

What bone forms the forehead and the superior part of the orbit and also what bones does it articulate with?

- Hyoid bone muscle attachment - Important for mastication, swallowing and speech body of hyoid, greater & lesser cornu

What bone is suspended in the neck, forming the base of tongue and larynx, wha function does it serve, what are its specific parts?

Mandible

What bone is the only freely movable bone of skull?

Maxillary process of the zygomatic bone

What bone with its specific parts forms the infraorbital rim?

Squamous portion of the zygomatic process of the temporal bone and the temporal process of the zygomatic bone

What bones and their specific parts form the zygomatic arch of the face?

Frontal & Nasal Bone

What bones are at the junction formed by the nasion?

Maxilla and ethmoid

What bones form the lateral boundaries of the nasal cavity?

- Temporal bones, they articulate with one zygomatic and one parietal bone each, occipital bone and the mandible 3 portions: - Squamous: flat portion - Tympanic: small irregularly shaped portion associated with the ear canal - Petrous: inferiorly located and helps form the cranial floor

What bones form the lateral walls of the skull and with what bones do they articulate and of what three parts are they composed?

Paired nasal bones

What bones form the the bridge of the nose?

Petrotympanic fissure

What bony demarcation is located posterior to the articulation part of the temporal bone through which the chorda tympani nerve emerges?

Mastoid notch is medial, inferior and medial is the styloid process

What bony demarcation on the large roughened projection of the temporal bone is posterior to the external acoustic meatus and what bony demarcation is inferior and medial?

Supraorbital notch, the supraorbital artery and nerve travel from the orbit to the forehead.

What bony demarcation when palpated causes patient discomfort and is located on the medial part of the curved elevations superior to the orbit and also what passes through it?

Secondary sinusitis and perforation due to infection, trauma or extraction

What can happen clinically given that the maxillary sinus is in direct contact with the mucosa of the maxillary sinus?

Ethmoid bone, it articulates with the frontal, sphenoid, lacrimal and maxillary bones as well

What cranial bone is single, in the middle of the skull and adjoins the vomer at its inferior and posterior border and also what other bones does it articulate with?

Mandibular notch

What depression is located between the coronoid process and the condyle of the mandible?

Lacrimal fossa, it contains the lacrimal gland which produces lacrimal fluid (tears) which the lacrimal fluid then drains into the nasal cavity through the nasolacrimal duct

What depression is located just inside the lateral part of the supraorbital ridge and what did it contain in life and also what did it produce?

between the lateral and medial plates: pterygoid fossa

What fossa is located between the plates of the sphenoid bone?

- Infratemporal fossa, boundaries include superiorly the greater wing of the sphenoid bone, anteriorly- the maxillary tuberosity, medially-the lateral pterygoid and laterally- the ramus of the mandible and the zygomatic arch. - It contains the mandibular division of the 5th cranial or trigeminal nerve (including the alveolar and lingual nerves) the pterygoid plexu and pterygoid muscles.

What fossa is located inferior to the anterior part of the temporal fossa and what bones form its area and also what are its boundaries?

Nasal meatus, the opening through which the paranasal sinuses or nasolacrimal duct communicated with the nasal cavity.

What groove is beneath each nasal conchae and what is the function of their openings?

Mylohyoid groove, mylohyiod nerve and blood vessels

What groove is near to the mandibular foramen and what travels in it?

Crest

What is a general term for a prominent often roughened border or ridge on bone?

Spine

What is a general term for an abrupt prominence on bone that may be blunt or sharply pointed?

Notch

What is a general term for an indentation at the edge of the bone?

Canal

What is a longer, narrow tubelike opening in the bone?

Sulcus/sulci

What is a shallow depression or groove on bone, which usually marks the course of a blood vessel?

A narrow strip of the parietal bone, the squamous portion of the temporal bone. Temporal surface of the greater wing of the sphenoid bone, it contains the body of the temporalis muscle and area blood vessels and nerves.

What is located in this fan-shaped depression on the lateral surface of the skull?

Inferior border of the 2 funnel shapes cavities. Posterior nasal apertures or choanae. Superior border of each aperture is formed by the vomer and the sphenoid bone. Posterior edge of the vomer forms the medial border of the posterior nasal apertures are the posterior openings of the nasal cavity.

What is located on the posterior border of the hard palate and what bones form these structures?

Piriform Aperature

What is the anterior opening of the nasal cavity?

Articulation

What is the area of the skeleton where the bones are joined to each other?

Coronoid notch

What is the concave forward curve on the anterior border of the lower jaw that serves as a landmark for a dental block?

Mandibular symphysis

What is the faint ridge on the external surface of the midline of the lower jaw?

Basilar portion, midline projection is the pharyngeal tubercle

What is the four-sided plate on the occipital bone that is anterior to the foramen magnum and what is its midline projection?

Arch

What is the general term for a bone that is shaped like a bridge, with a bowlike outline?

Cornu

What is the general term for a hornlike prominence on bone?

Tuberosity

What is the general term for a large, often rough prominence on bone that usually serves as an attachment for muscles or tendons?

Condyle

What is the general term for a relatively large, convex prominence on bone that is usually involved in joints?

Head

What is the general term for a rounded surface projecting from a bone by a neck?

Line

What is the general term for a straight small ridge on bone?

Plate

What is the general term for an area of bone that consists of a flat bony structure?

Process

What is the general term for any type of bony prominence?

Infraorbital sulcus

What is the groove in the floor of the orbital surface and what canal does it become?

Body of the mandible

What is the heavy horizontal part of the lower jaw inferior to the mental foramen called?

Articular fossa

What is the landmark on the inferior part of the temporal bone that is part of the articulation of the temporomandibular joint?

Foramen lacerum

What is the large irregularly shaped opening on the external surface of the skull., which in life was filled with cartilage?

- Foramen magnum of the occipital bone - Spinal cord, vertebral arteries and 11th cranial (accessory) nerve pass through it.

What is the largest opening on the inferior view of the skull and in what bone is it located and what passes through it?

Carotid canal carries the internal carotid artery and sympathetic carotid plexus. Bony projection that is lateral and posterior is the styloid process.

What is the more posterior opening in the petrous part of the temporal bone and what passes through it and also what pointed bony projection is nearby?

Mental foramen, mental nerve and blood vessels into the mandibular canal.

What is the opening on the external surface of the lower jaw that is usually between the apices of the mandibular first and second premolars and what does it carry?

Stylomastoid foramen, is named for its location between the styloid process and mastoid process

What is the opening on the temporal bone that carries the facial nerve and why is it named as such?

Jugular notch of the occipital bone, jugular notch of the temporal bone

What is the part of the occipital bone that forms the medial part of the jugular foramen and what bone does it articulate with?

- Optic Canal --> 2nd Cranial or Optic Nerve

What is the round opening in the orbital apex termed and what passes through it?

Ramus, from the body of the mandible, coronoid process

What is the stout, flat plate of the lower jaw, from what does it extend upward and backward, and what is its anterior border termed?

- zygomatic arch, temporozygomatic suture, the temporal process of the zygomatic bone and the zygomatic process of the temporal bone. - serves as an origin for the masseter muscle.

What is the term for the cheekbone area and what suture is located on it and also which bones form this area?

Hamulus

What is the term for the curved process on the inferior part of the medial plate of the sphenoid bone?

Pterygoid fovea

What is the triangular depression on the anterior surface of the condyle?

Cristal galli, it serves as an attachment for layers covering the brain

What is the vertical midline continuation of the perpendicular plate into the cranial cavity and what is its function?

Nasal septum anteriorly- nasal cartilage inferiorly and the perpendicular plate of ethmoid bone superiorly, the posterior portions of the nasal septum are formed by the vomer

What is the vertical partition of the nasal cavity and what bones form its anterior and posterior parts?

Stylomastoid foramen, 7th cranial or facial nerve

What opening is immediately posterior to the more posterior opening in the petrous part of the temporal bone and what passes through it from the skull to the face?

Incisive foramen, the branches of the right and left nasopalatine nerves and blood vessels from the nasal cavity to the palate.

What opening is located on the anterior midline part of the palatine process and what does it carry and also what clinical landmark is present over it?

- jugular foramen - internal jugular vein and 9th cranial (glossopharyngeal) nerve, 10th cranial (vagus) nerve, 11th cranial (accessory) nerve pass through

What opening is medial to the styloid process and is easier to see if you tilt the skull to one side and also what passes through it?

Zygomatic bones, which articulate with the frontal, temporal, sphenoid and maxillary bones

What pair of facial bones form the cheekbones and what bones do they articulate with?

Inferior nasal conchae which are composed of fragile, thin, spongy bone curved onto itself like a scroll. They articulate with the ethmoid, lacrimal, palatine and maxillary bones.

What pair of facial bones project off the maxillae to form the lateral walls of the nasal cavity and what type of bone are they composed of and also what bones do they articulate with?

- Parietal bones are paired cranial bones that articulate with each other at the sagittal suture - Parietal bones articulate with the occipital, frontal, paired temporal and sphenoid bones

What paired bones articulate with each other at the sagittal suture and what other bones do they articulate with?

Lacrimal bones

What paired facial bones are irregular thin plates of bone that form a small part of the anterior medial wall of the orbit?

Nasal bones, superior to the piriform aperture, they articulate with the frontal bone superiorly and the maxillae laterally

What paired facial bones form the bridge of the nose and what opening in the skull are they superior to and also what bones do they articulate with?

Medial orbit wall, which is medial to the nasal conchae

What part of the orbit does the orbital plate of the ethmoid bone form and where is its location in relationship to the nasal conchae?

Frontal process of the maxilla articulates with the frontal bone to form the medial orbital rim with the lacrimal bone on its anterior surface

What part of the upper jaw forms a part of the medial orbital rim and what other bones are involved in this formation?

Vertical plates of palatine bones

What plates contribute a small lip of bone to the orbital apex?

Zygomatic process of the frontal bone

What projection is located on the frontal bone lateral to the orbit?

Submandibular fossa, sublingual fossa

What shallow depression is located just inferior to the mandibular posterior teeth and which similar depression is superior to the anterior part of the mylohyoid line?

Sphenoid bone

What single cranial bone is midline and complex and contains the superior orbital fissue, foramen ovale foramen rotundum, and the foramen spinosum?

- Median palatine suture a midline articulation between the 2 palatine processes of the maxillae anteriorly and the 2 horizontal plates of the palatine bones posteriorly. The transverse palatine suture. - Articulation between the 2 palatine processes of the maxillae and the 2 horizontal plates of the palatine bones

What sutures are located on the hard palate and what bones does it show the articulation between?

In the petrous part of the temporal bone, the 7th cranial (facial) nerve and 8th cranial (vestibulocochlear) nerve

Where is the internal acoustic meatus located and what passes through it?

Atlas (1st cervical vertebra)

Which cervical vertebra articulates with the skull and what are its specific parts?

- Temporal fossa, its boundaries include superiorly and posterior. Inferior temporal line, anteriorly the frontal process of the zygomatic bone, medially the surface of the temporal bone and laterally the zygomatic arch. Inferiorly the infratemporal crest on the greater wing of the sphenoid bone. - Its formed by the zygomatic, frontal greater wing of the sphenoid, temporal and parietal bones.

Which fossa is flat and fan-shaped on the lateral surface of the skull. What are its boundaries and what bones form its area?

To be able to diagnose diseases

Why must a dental professional know the normal anatomy of the bones of the head and neck?

They articulate with the frontal, lacrimal, nasal, inferior nasal conchae, vomer, sphenoid, ethmoid, palatine and zygomatic bones.

With which bones does the upper jaw articulate?

- Aperture: narrow opening - Ostium/ostia: smaller opening, especially as an entrance into a hollow organ or canal - Fissure: opening in bone, narrow cleftlike opening - Meatus: type of canal - Canal: longer narrow tubelike opening in a bone - Foramen/foramina: short windowlike openings in bone

Name six types of bone openings and describe each one.

-Frontal Bone: roof or superior wall - Ethmoid & Lacrimal Bone: medial wall - Zygomatic & Sphenoid Bone: lateral wall - Sphenoid Bone, Maxilla & Palatine Bone: apex or base

Name the bones that form the orbit and what part they form (cover the four walls and apex).

Single occipital bone, frontal bone, sphenoid bone, ethmoid bone, paired parietal bones, temporal bones

Name the cranial bones.

- single vomer - mandible - paired lacrimal bones - nasal bones - inferior nasal conchae - zygomatic bones - maxillae

Name the facial bones of the skull.

- Greater palatine foramina is located in the posterolateral region of each of the palatine bones usually at the apex of the maxillary third molar, which transmits the greater palatine nerve and blood vessels and is a landmark for administration of the greater palatine anesthesia block. - Lesser palatine foramina, transmits the lesser palatine nerve and blood vessels to the soft palate and tonsils, both foramina openings of the pterygopalatine canal that carries the descending palatine nerves and blood vessels from the pterygopalatine fossa to the palate.

State the usual location of the greater and lesser palatine foramina, what each transmits, and what canals they are related to.

Alveolar process

What bone covers each tooth of the upper jaw?

Frontal process of the zygomatic bone

What bone with its specific parts forms the anterior lateral orbital wall?

Lingula

What bony demarcation on the mandible serves as an attachment for the sphenomandibular ligament?

Pterygopalatine fossa

What fossa of the skull is a cone-shaped depression between the pterygoid process and the maxillary tuberosity?

Foramen/ foramina

What is a short windowlike opening in the bone?

Perforation due to secondary sinusitis

What is an abnormal hole in the wall of the sinus and why does it occur?

Aperture

What is another general term used for an opening or orifice in bone?

Mental protuberance

What is bony prominence of the chin?

Foramen ovale, mandibular division of the 5th cranial or trigeminal nerve

What is larger anterior oval opening on the sphenoid bone and what passes through it?

Fissure

What is narrow, cleftlike opening in the bone?

Mandibular foramen, mandibular canal, inferior alveolar nerve and blood vessels

What is the opening on the internal surface of the ramus and what canal is it connected to and also what passes through it?

Retromolar triangle

What is the rounded roughened area on each lateral edge of the mandible that is just posterior to the most distal molar?

Infraorbital foramen

What is the single opening on the facial surface of each side of the upper jaw that is a landmark for a dental block and causes a mild ache when palpated?

Foramen spinosum carries the middle meningeal artery into the cranial cavity. Spine of the sphenoid bone which is at the posterior extremity of the sphenoid bone.

What is the smaller and more posterior opening on the sphenoid bone and what passes through it and also what spine is located nearby?

Temporal bone and the mandible

What is the temporomandibular joint an articulation between?

Mylohyoid line or internal oblique ridge, point of attachment for the mylohyoid muscle

What landmark is located on the medial surface of the body of the mandible and what is its function?

Maxillary tuberosity, one or more posterior superior alveolar foramina

What landmark is on the posterior part of the upper jaw that is rounded roughened elevation and what perforates it?

Anterior is the articular eminence and posteriorly is the postglenoid process, both are portions of the squamous portion of the temporal bone that articulate with the mandible at the TMJ

What landmark on the temporal bone is anterior to the articulation part of the temporomandibular joint and which one is posterior?

Canine fossa

What landmark on the upper jaw is posterosuperior to the roots of the maxillary canine teeth?

Inferior orbital fissure, it carries the zygomatic nerves, infraorbital artery, and inferior opthalmic vein

What landmark separates the upper jaw from the sphenoid bone and what passes through it?

Mastoid process, which is composed of mastoid air cells, it communicates with the middle ear cavity, also serves as a site for attachment of the large muscles of the neck such as the sternocleidomastoid muscle.

What large roughened projection of the temporal bone is posterior to the external acoustic meatus and what is it composed of and also what purposes does it serve?

Alveolar process

What part of the lower jaw contains the roots of the teeth?

Vomer articulates with the ethmoid bone on its anterosuperior border, the nasal cartilage anteriorly, the palatine bones and maxillae inferiorly and the sphenoid bone on its posterosuperior border. The posteroinferior border is free of bony articulation.

What single facial bone forms the posterior part of the nasal cavity and what bone does it articulate with and also what part is free of any bony articulation?

The palatine bones, they articulate with each other, the maxillae and sphenoid

What skull bone could be considered a facial bone consisting of a horizontal and vertical plate and what bones does it articulate with?

Pterygoid canal that extends into the pterygopalatine fossa and carries the pterygoid nerve and blood vessels.

What small canal is located on the superior border of each of these structures on the posterior border of the palate and what do they open into and also what passes through it?

Body of the maxilla articulates with the frontal bone to form the medial orbital rim with the lacrimal bone on its anterior surface

What specific part of the upper jaw contains the maxillary sinuses and what are its surfaces?

- Maxillary artery and its thirds part branches, including the infraorbital and sphenopalatine arteries, and the maxillary nerve (or division) of the 5th cranial also pterygopalatine ganglion - pterygoid muscles, maxillary artery and its second part branches including MMA, inferior alveolar artery and posterior superior alveolar artery. Mandibular nerve (or division) of 5th cranial including inferior alveolar and lingual nerves.

What structures pass through the pterygopalatine and infratemporal fossae?

Eminence/tubercle

What two general terms can be used to describe a rounded elevation on the bony surface?

Posterior open into the superior meatus of the nasal cavity, the middle and anterior open into the middle meatus

Where do the posterior ethmoid air cells open and where do the middle and anterior ethmoid air cells open?

Anterior portion of the skull's inferior aspect bordered by the alveolar process of the maxilla with its maxillary teeth. Hard palate is formed by the 2 palatine processes of the maxillae and the 2 horizontal plates of the palatine bones.

Where is the hard palate located and which teeth are located near it and also what bone borders it?

Its formed at the junction of the lacrimal and maxillary bones, lacrimal fluid or tears from the lacrimal gland are drained through this duct into the inferior nasal meatus.

Where is the nasolacrimal duct located and what function does it serve?

The perpendicular plate is perpendicular to the horizontal cribiform plate, and aids the vomer and nasal septal cartilage in forming the nasal septum

Where is the perpendicular plate in relationship to the cribiform plate and what midline nasal feature does is help form?

- Axis (2nd cervical vertebra) - Dens articulates with anterior arch of the 1st cervical vertebra

Which cervical vertebra is characterized by a dens and what does it articulate with?

Ostium

Which opening in bone is a small one that also serves as an entrance into a hollow organ or canal?

Meatus

Which opening in bone is a type of canal?

Pyramid shape

Describe the shape of each maxillary sinus and its specific parts.

Temporal fossa seen laterally is formed by several bones and contains the body of the temporalis muscle, inferior to the temporal fossa is the infratemporal fossa, deep to the infratemporal fossa is the pterygopalatine fossae.

Discuss the fossae of the skull and where they are located.

2 horizontal plates articulate with each other at the posterior portion of the median palatine suture, and they articulate with the palatine processes of the maxillae anteriorly. The median palatine covers the suture.

Discuss the median palatine suture, the bones involved in its formation, and the clinical landmark its related to?

They become inflamed and congested with mucous as in primary sinusitis

Discuss what happens to the sinuses when they become involved with allergies and/or infections.