Head And Neck Anatomy(miscellaneous) Flashcards
Define the skull
A bony structure
What is the classification of the bones of the skull?
What is the function of the skull?
(1) supports the face
(2) forms a protective cavity for the brain
What is the structure of the skull?
It is comprised of many bones,which are:-
(1) formed by intramembranous ossification
(2) joined by sutures (fibrous joints)
What is the other name of the cranium?
Neurocranium
Define the cranium
Formed by the superior aspect of the skull
What is the function of the cranium?
It encloses and protects the(Mnemonic;MBC)
(1) meninges
(2) brain
(3) cerebral vasculature
What are the anatomical subdivisions of the cranium?
1st/ Cranial roof (aka; calvarium)
comprised of the following bones (Mnemonic;FO2):-
(1)frontal bone
(2)occipital bone
(3)2 parietal bones
2nd/ Cranial base
-comprised of the following bones:-
(1) frontal bones
(2) ethmoid bones
(3) sphenoid bones
(4) occipital bones
(5) temporal bones
(6) parietal bones
-these bones articulate with the:-
(1) 1st cervical vertebrae (atlas)
(2) facial bones
(3) mandible (jaw)
What are the bones that form the cranial roof(calvarium)
comprised of the following bones(Mnemonic;FO2):-
(1)frontal bone
(2)occipital bone
(3)2 parietal bones
What are the bones that form the cranial base?
comprised of the following bones:-
(1) frontal bones
(2) ethmoid bones
(3) sphenoid bones
(4) occipital bones
(5) temporal bones
(6) parietal bones
What are the structures that the bones of the cranial base articulate with?
these bones articulate with the:-
Mnemonic;1st FM
(1) 1st cervical vertebrae (atlas)
(2) facial bones
(3) mandible (jaw)
Discuss pterion
Definition: a junction
Shape: H-shaped
Location: a junction between the
Mnemonic; TWO SPECIFIC PARIETAL FRACTURES
(1) Temporal bone
(2) Sphenoid bone
(3) Parietal bone
(4) Frontal bone
Define pterion
A junction
What is the other name of the cranial roof?
Calvarium
What is the shape of the pterion?
H-shaped
What is the location of the pterion?
A junction between the
Mnemonic; TWO SPECIFIC PARIETAL FRACTURES
(1) temporal bone
(2) parietal bone
(3) frontal bone
(4) sphenoid bone
What is the clinical significance of the pterion?
What are the bones that form the pterion?
Mnemonic; TWO SPECIFIC PARIETAL FRACTURES
What are the typical causes of cranial fractures?
Typically arise from:-
(1) blunt force OR
(2) penetrating trauma
What is the anatomical part of clinical importance when considering cranial fractures? and why?
The pterion, because it is a weak area of the skull,where the anterior middle meningeal artery is at risk of damage
What is the anatomical structure that might be injured in fractures involving the pterion and what is the sequale?
The anterior middle meningeal artery (aka,frontal branch of the middle meningeal artery), causing blood to accumulate between the skull and the dura matter ,forming an extra dural haematoma.
What is the other name of the face or facial skeleton?
Viscerocranium
What is the function of the face or facial skeleton?
Supports the soft tissue of the face
What is the number of bones of the facial skeleton?
14 bones
What is the function of the bones of the face or facial skeleton?
They fuse to house the(Mnemonic;SOON)
(1) orbits of the eyes
(2) nasal cavity
(3) oral cavity
(4) sinuses
What is the other name for the facial bones?
Bones of the facial skeleton
Enumerate the facial bones
Mnemonic;Zaman Laily Night In PM Very Moony
Discuss zygomatic bone very briefly
Function
Forms the cheek bones of the face
Articulates with the (Mnemonic;FSTM على وزن سستم)
(1) Frontal bone
(2) Sphenoid bone
(3) Temporal bone
(4) Maxilla bone
How many zygomatic bones are there in the facial bones?
2
What is the function of the zygomatic bone?
Forms the cheek bones of the face
Enumerate the bones with which the zygomatic bone articulates?
Articulates with the (Mnemonic;FSTM على وزن سستم)
(1) Frontal bone
(2) Sphenoid bone
(3) Temporal bone
(4) Maxilla bone
Discuss zygomatic arch fracture
Aetiology
Trauma to the side of the face
Clinical features
Displaced fractures can damage the nearby infra orbital nerve leading to ipsilateral parasthaesia of the cheek,nose and lips
What is the aetiology of the zygomatic arch fracture?
Trauma to the side of the face
What is the clinical features of the zygomatic arch fracture?
Displaced fractures can damage the nearby infra orbital nerve leading to ipsilateral parasthaesia of the cheek,nose and lips
What is nerve injured by displaced zygomatic arch fracture?
Infraorbital nerve leading to ipsilateral parasthaesia of the cheek,nose and lips
What is the sequelae of the infraorbital nerve injury by displaced zygomatic arch fractures?
Ipsilateral paraesthesia of the cheek,nose and lip
Discuss lacrimal bones very briefly
(1) the smallest bones of the face
(2) they form part of the medial wall of the orbit
How many lacrimal bones are there in the facial bones?
2
What is the feature of the lacrimal bones?
They are the smallest bones of the face
What is the function of the lacrimal bones?
They form part of the medial wall of the orbit
Discuss the nasal bones very briefly
+Shape: slender
+Location: at the bridge of the nose
What is the shape of the nasal bones?
Slender
What is the location of the nasal bones?
At the bridge of the nose
How many nasal bones are there in the facial bones?
2
Discuss nasal bones fractures very briefly
Incidence: the most common facial fractures
Risk factor: due to the prominent position of the nasal
bones at the bridge of the nose
C/P: (1) significant soft tissue swelling
(2) epistaxis
What is the incidence of nasal bones fractures?
the most common facial fractures
What is the risk factor of the nasal bone fractures?
due to the prominenet position of the nasal bones at the bridge of the nose
What are the clinical features of the nasal bones fractures?
(1) significant soft tissue swelling
(2) epistaxis
Discus inferior nasal conchae very briefly
+location
within the nasal cavity
+Function
these bones increase the surface area of the nasal cavity,thus increasing the amount of inspired air that can come into contact with cavity walls.
What is the location of the inferior nasal chonchea
within the nasal cavity
How many inferior nasal chonchae are there in the facial bones?
2
What is the function of the inferior nasal chonchae?
these bones increase the surface area of the nasal cavity,thus increasing the amount of inspired air that can come into contact with cavity walls.
discuss the palatine bone very briefly
+Location
at the rear of oral cavity
+Function
forms part of the hard palate
How many palatine bones are there in the facial bones?
2
What is the location of the palatine bone?
at the rear of oral cavity
What is the function of the palatine bone?
forms part of the had palate
How many maxilla bones are there in the facial bones?
2
What are the parts of the maxilla?
comprises part of the
(1) Upper jaw
(2) Hard palate
Discus maxillary fracture very briefly
+Aetiology
high energy trauma
+Classification
Le fort classification ,ranging from 1 to 3
What is the aetiology of the maxillary fracture?
high energy trauma
What is the classification of the maxillary fracture?
Le Fort classification ,ranging from 1 to 3
How many vomer bones are there in the facial bones?
1
What is the function of the vomer?
forms the posterior aspect of the nasal septum
How many mandibular bones are there in the facial bones?
1
What is the location of the mandible?
inferiorly in the facial skeleton
What is the feature of the mandible?
the largest and strongest bone of the face
What is the function of the mandible?
(1) Forms the lower jaw
(2) Acts as a receptacle for the lower teeth
What is the anatomical part with which the mandible articulates with and where is that?
aticulates on either side with the temporal bone at the base of the cranium forming the temporomandibular joint (TMJ)
What are the parts of the mandible?
(1) Body
(2) 2 rami
(3) mandibular angle
What is the shape of the body of the mandible?
Mnemonic;CASH
(1) Horizontal
(2) Anteriorly
(3) Curved
(4) Shaped much like a horseshoe
What are the borders of the body of the mandible?
(1) Alveolar border(superior)- contains 16 sockets to hold the lower teeth
(2) Base(inferior)- for the attachment of the diagastric muscle medially
How many sockets are there in the alveolar border (superior) of the mandibular body?
contains 16 sockets to hold the lower teeth
What is the significance of the alveolar border (superior) of the mandibular body?
contains 16 sockets to hold the lower teeth
What is the significance of the base (inferior) of the mandibular body?
for the attachment of the diagastric muscle medially
Which muscle is attached to the base (inferior) of the mandibular body and on which direction?
diagastric+medially
What are the surfaces of the body of the mandible?
(1) External (lateral) surface
(2) Internal (medial) surface
What are the markings of the body of the mandible?
Mnemonics; 3M
(1) Mandibular symphysis
(2) Mental protuberance
(3) Mental foramen
Discuss Mandibular symphysis
+Definition
a ridge of bone
+Size
small
+Location
in the midline of the body of the mandible
+Embryological significance
Represents the fusion of the two halves of the mandibular body during development
Define the mandibular symphysis
a ridge of bone
What is the size of the mandibular symphysis?
small
What is the location of the mandibular symphysis?
in the midline of the body of the mandible
What is the embryological significance of he mandibular symphysis?
Represents the fusion of the two halves of the mandibular body during development
Discuss the mental protuberance
+Definition
an eminence enclosed by the mandibular symphysis
+Shape
Triangular
+Function
Forms the shape of the chin
Define the mental protuberance
an eminence enclosed by the mandibular symphysis
What is the shape of the mental protuberance?
Triangular
What is the function of the mental protuberance?
Forms the shape of the chin
Discuss mental foramen
+Location
(1) On the internal surface of the mandibular ramus
(2) Lateral to the mental protuberance
(3) Below the 2nd premolar teeth on either side
+Function
(1) It allows the inferior alveolar nerve and artery to exit the mandibular canal.
(2) When the inferior alveolar nerve passes through the mental foramen,it
becomes the mental nerve(innervates the skin of the lower lip and the front
of the chin).
What is the location of the mental foramen?
(1) On the internal surface of the mandibular ramus
(2) Lateral to the mental protuberance
(3) Below the 2nd premolar teeth on either side
What is the function of the mental foramen?
(1) It allows the inferior alveolar nerve and artery to exit the mandibular canal.
(2) When the inferior alveolar nerve passes through the mental foramen,it
becomes the mental nerve(innervates the skin of the lower lip and the front
of the chin).
What happens to the inferior alveolar nerve when it passes through the mental foramen?
It becomes the mental nerve(innervates the skin of the lower lip and the front of the chin)
What part of the face is innervated by the mental nerve?
skin of the
(1) lower lip
(2) front of the chin
How many mandibular rami are there?
2
What is the location of the mandibular rami?
(1) vertical
(2) posteriorly
(3) project perpendicularly upwards from the angle of the mandible
What are the parts of the mandibular rami?
What is the location of the head of the mandibular rami?
situated posteriorly
What is the anatomical part of the cranium with which the head of mandibular rami articulates with?
articulates on either side with the temporal bone at the base of the cranium forming the temporomandibular joint(TMJ)
What is the function of the neck of the mandibular rami?
(1) supports the head of the mandibular ramus
(2) for attachment of the lateral pterygoid muscle
What muscle attaches to the neck of the mandibular rami?
lateral pterygoid
What is the function of the coronoid process of the mandibular rami?
for attachment of the temporalis muscle
What muscle attaches to the coronoid process of the mandibular rami?
temporalis
Define the foramen in anatomy?
any opening through which neurovascular structures can travel
How many foramen are there in the mandible?
2
Name the foramen in the mandible
(1) Mandibular foramen
(2) Mental foramen
Discuss mandibular foramen
+Location
on the internal surface of the mandibular ramus
+Function
It serves as a conduit for the inferior alveolar nerve and inferior alveolar artery. They travel through the mandibular foramen, into the mandibular canal, and exit at the mental foramen.
What is the location of the mandibular foramen?
on the internal surface of the mandibular ramus
What is the function of the mandibular foramen?
It serves as a conduit for the inferior alveolar nerve and inferior alveolar artery. They travel through the mandibular foramen, into the mandibular canal, and exit at the mental foramen.
Discuss the muscular attachments to different parts of the mandible
What are the muscular attachments of the mandibular body?
1st/ External (lateral) surface;
Mnemonic;Men Bodies Placed Deeply Down
(1) Mentalis
(2) Buccinator
(3) Platysma
(4) Depressor labii inferioris
(5) Depressor anguli oris
2nd/Internal (medial) surface;
Mnemonic;Go Go My Darling
(1) Genioglossus
(2) Geniohyoid
(3) Mylohyoid
(4) Digastric
What are the muscular attachments of the external (lateral) surface of the mandibular body?
Mnemonic;Men Bodies Placed Deeply Down
(1) Mentalis
(2) Buccinator
(3) Platysma
(4) Depressor labii inferioris
(5) Depressor anguli oris
What are the muscular attachments of the internal (medial) surface of the mandibular body?
Mnemonic;Go Go My Darling
(1) Genioglossus
(2) Geniohyoid
(3) Mylohyoid
(4) Digastric
What are the muscular attachments of the mandibular rami?
Mnemonic; MTML
(1) Masseter: attaches to the mandibular rami on each side
(2) Temporalis: attaches to the coronoid process
(3) Medial pterygoid: inserts into the mandibular ramus near the angle of the
mandible
(4) Lateral pterygoid: inserts into the neck of the mandible
What are the four most common facial fracture type?
Mnemonic;Zimmermann Neilsen Media Man
(1) Zygomatic fracture
(2) Nasal fracture
(3) Maxillary fracture
(4) Mandibular fracture
What is the incidence of fractures of the facial skeleton?
Relatively common
What is the aetiology of fractures of the facial skeleton?
(1) RTA
(2) Fist fights
(3) Falls
Discuss mandibular fracture very briefly
+Location
(1) Often bilateral
(2) Rarely occurs in isolation:
Much like fractures of the pelvic brim, a fracture on one side is frequently associated with a fracture on the
contralateral side.Therefore, if one fracture is observed, another should be searched for.
For example, a fractured neck of the mandible is often observed in conjunction with a fracture of the contralateral mandibular body.
+Aetiology
(1) Direct- at the side of trauma
(2) Indirect- at the contralateral side due to transmitted forces
+Clinical features
1st/General features:
(1) Pain at the fracture site
(2) Malocclusion- misalignment of the teeth
2nd/Specific features of fractures related to an anatomical site
- Fractures of the coronoid process: (1) Uncommon
(2) Usually singular
- Fractures of th neck of the mandible:
(1) Often transverse
(2) Usually accompanied with dislocation of the temporomandibular joint (TMJ).
- Fractures of the angle of the mandible:
(1) Usually oblique
(2) May involve the alveolus of 3rd molar teeth
- Fractures of the body of the mandible: frequently pass through the canine
tooth
What is the location of the mandibular fracture?
(1) Often bilateral
(2) Rarely occurs in isolation:
Much like fractures of the pelvic brim, a fracture on one side is
requently associated with a fracture on the contralateral side.
Therefore, if one fracture is observed, another should be searched for.
For example, a fractured neck of the mandible is often observed in
conjunction with a fracture of the contralateral mandibular body.
What is the aetiology of the mandibular fracture?
(1) Direct- at the side of trauma
(2) Indirect- at the contralateral side due to transmitted forces
What is the direct aetiology of the mandibular fracture?
at the side of trauma
What is the indirect aetilogy of the mandibuar fracture?
at the contralateral side due to transmitted forces
What are the clinical features of the mandibular fracture?
1st/General features: (1) Pain at the fracture site
(2) Malocclusion- misalignment of the teeth
2nd/Fractures related to the anatomical sites
- fractures of the coronoid process: (1) Uncommon
(2) Usually singular
- Fractures of th neck of the mandible: (1) Often transverse
(2) Usually accompanied with dislocation
of the temporomandibular joint (TMJ).
- Fractures of the angle of the mandible: (1) Usually oblique
(2) May involve the alveolus of the 3rd
molar
- Fractures of the body of the mandible: frequently pass through the canine
tooth
What are the general clinical features of the mandibular fractures?
(1) Pain at the fracture site
(2) Malocclusion- misalignment of the teeth
Define malocclusion and what is the cause?
Misalignment of the teeth+occurs in mandibular fracture
What are the specific features of fractures related to anatomical sites of the mandible?
- fractures of the coronoid process: (1) Uncommon
(2) Usually singular - Fractures of th neck of the mandible: (1) Often transverse
(2) Usually accompanied with dislocation
of the temporomandibular joint (TMJ). - Fractures of the angle of the mandible: (1) Usually oblique
(2) May involve the alveolus of the 3rd
molar - Fractures of the body of the mandible: frequently pass through the canine
tooth
What are the specific features of the fractures of the coronoid process?
(1) Uncommon
(2) Usually singular
What are the specific features of the fractures of the neck of the mandible?
(1) Often transverse
(2) Usually accompanied with dislocation of the temporomandibular joint (TMJ)
What are the specific features of the fractures of the angle of the mandible?
(1) Usually oblique
(2) May involve the alveolus of the 3rd molar
What are the specific features of the fractures of the body of the mandible?
frequently pass through the canine tooth
Define the frontal bone of the skull
(1) one of the 8 bones that make up the cranium
(2) the superior aspect of the skull
What is the origin of the name frontal bone in latin?
derived from the latin (frons), meaning forehead
What the function of the frontal bone in general?
(1) encloses and protects the brain
(2) forms the anterosuperior aspect of the cranium
What the shape of the frontal bone in general?
(1) Unpaired
(2) Shell-shaped
How many parts form the frontal bone?
4
What are the 4 parts that form the frontal bone?
consists of 4 parts:(Mnemonic; SON)
(1) Squamous
(2) Orbital (x2)
(3) Nasal
What is the feature of the squamous part of the frontal bone?
the largest component of the frontal bone
What is the largest component of the frontal bone?
squamous part
What are the parts of the squamous part of the frontal bone?
1st/Surfaces
(1) External surface
(2) Internal surface: 1)Sagital sulcus
2)Frontal crest
3)Groove for the anterior meningeal artery
2nd/Frontal sinuses
(1) Anterior plate or table
(2) Posterior plate or table
3rd/Supraorbital margin or border
4th/Supraorbital foramen
Discuss the external surface of the squamous part of the frontal bone?
+Shape: Convex
+Function: Forms the shape of the forehead
What is the shape of the external surface of the squamous part of the frontal bone?
convex
What is the function of the external surface of the squamous part of the frontal bone?
Forms the shape of the forehead
What are the features of the internal surface of the squamous part of the frontal bone?
Discuss sagittal sulcus of the internal surface of the squamous bone very briefly
+Definition: a groove
+ Shape: vertical
+ Location: in the midline of the frontal bone
+ Contents: superior sagittal sinus
What is the definition of sagittal sulcus of the internal surface of the squamous bone
a groove
What is the shape of sagittal sulcus of the internal surface of the squamous bone
Vertical
What is the location of sagittal sulcus of the internal surface of the squamous bone
In the midline of the frontal bone
What are the contents of sagittal sulcus of the internal surface of the squamous bone
superior sagittal sinus
Discuss frontal crest of the internal surface of the squamous part of frontal bone
+Definition: extension of the sagittal sulcus edges
+Function: forms an attachment for the falx cerebri
Define frontal crest of the internal surface of the squamous part of frontal bone
(1) a body ridge projecting upward
(2) extension of the sagittal sulcus edges
What is the location of the frontal crest of the internal surface of the squamous part of frontal bone
Midline of the frontal bone
What is the function of the frontal crest of the internal surface of the squamous part of frontal bone
forms an attachment for the falx cerebri
How the falx cerebri is related to the frontal crest of the squamous part of frontal bone?
The falx cerebri also forms part of its attachments with the frontal crest of the internal surface the squamous part of the frontal bone.
Discuss the frontal sinuses of the frontal bone
+ Location
(1) Housed by the squamous part of the frontal bone
(2) Above the orbits
(3) Either side of the midline of the face
+Structure
Separated by a septum
+Parts
(1)Anterior plate
(2)Posterior plate
What is the location of the frontal sinuses of the frontal bone?
(1) Housed by the squamous part of the frontal bone
(2) Above the orbits
(3) Either side of the midline of the face
What is the structure of the frontal sinuses of the frontal bone?
separated by a septum
What are the parts of the frontal sinuses of the frontal bone?
(1)Anterior plate
(2)Posterior plate
What is the function of the supraorbital margin of the squamous part of frontal bone
(1) Separates the squamous part of the frontal bone from its orbital part
(2) Contains the supraorbital foramen
Discuss the supraorbital foramen of the squamous part of the frontal bone?
+Location: contained within the supraorbital margin or border
+Contents: supraorbital vessels and nerves
What is the location of the supraorbital foramen of the squamous part of the frontal bone?
contained within the supraorbital margin or border
What are the contents of the supraorbital foramen of the squamous part of the frontal bone?
supraorbital vessels and nerves
How many orbital parts of the frontal bone are there?
2
Define the orbital part of the frontal bone?
A plate
What is the shape of the orbital part of frontal bone?
(1) Triangular shaped
(2) Flat
What is the location of the orbital part of frontal bone?
Extends posteriorly from the supraorbital margin or border of the squamous part of frontal bone
What is the function of the orbital part of frontal bone?
forms the roof(superior border) of the orbit
What is the parts of the orbital part of frontal bone?
(1) Anterolateral portion (lacrimal fossa): where the lacrimal gland sits
(2) Anteromedial portion (trochlear fossa): for attachment of the cartilaginous pulley of the superior oblique muscle
What is the other name for the anterolateral portion of the orbital part of frontal bone?
lacrimal fossa
What is the function of the anterolateral portion of the orbital part of frontal bone?
where the lacrimal gland sits
What is the other name for the anteromedial portion of the orbital part of frontal bone?
(1) Trochlear fossa
(2) Trochlea of the superior oblique muscle
What is the other name for the trochlear fossa of the orbital part of frontal bone?
(1) Anteromedial portion of the orbital part of frontal bone
(2) Trochlea of the superior oblique muscle
What is the function of the anteromedial portion of the orbital part of frontal bone?
for attachment of the cartilaginous pulley of superior oblique muscle(named the ‘trochlea’ of the superior oblique muscle)
What is the attachment of the trochlear fossa of the orbital part of frontal bone?
for attachment of the cartilaginous pulley of superior oblique muscle(named the ‘trochlea’ of the superior oblique muscle)
What is the size of the nasal part of the frontal bone?
small area
What is the location of the nasal part of the frontal bone?
Projects inferiorly between the supraorbital margins or borders of the squamous part of frontal bone
What is the function of the nasal part of frontal bone?
Serves as an area of articulation for the:
(1) Nasal bones and
(2) Frontal processes of the maxilla
What is the marking of the nasal part of frontal bone?
Nasal spine
Discuss Nasal spine of nasal part of the frontal bone
+Location: Protrudes from the central portion
+Function: Supports the bridge of the nose
What is the location of the nasal spine of the nasal part of frontal bone?
protrudes from the central portion
What is the function of the nasal spine of the nasal part of frontal bone?
supports the bridge of the nose
Discuss muscular attachments of the frontal bone
no specific muscular attachment to the frontal bone
Discuss frontal bone articulations
How many bones of the skull articulate with the frontal bone?
12
What are the unpaired bones of the skull that articulate with the frontal bone?
(1) Ethmoid
(2) Sphenoid
What are the paired bones of the skull that articulate with the frontal bone?
Mnemonic; لن ننسى زمانا مر بنا
(1) Lacrimal
(2) Nasal
(3) Zygomatic
(4) Maxilla
(5) Parietal
Discuss frontal sinusitis very briefly
+Definition: Inflammation of the frontal sinus
+Incidence: Relatively common
+Aetiology: Infection
+Complication:
If untreated,infection can spread to the surrounding structures in the orbit or cranial cavity,leading to:-
(1) Orbital celulitis
(2) Epidural and subdural abscesses
(3) Meningitis
Define frontal sinusitis
Inflammation of the frontal sinus
What is the incidence of frontal sinusitis in general?
Relatively common
What is the aetiology of the of the frontal sinusitis?
Infection
What are the complications of frontal sinusitis?
If untreated,infection can spread to the surrounding structures in the orbit or cranial cavity,leading to:-
(1) Orbital celulitis
(2) Epidural and subdural abscesses
(3) Meningitis
Discuss frontal sinus fracture very briefly
+Aetiology: (1) MVA
(2) Falls
+C/P:
(1)Anterior table of the skull disruption: Frontal depression(the characteristic
clinical sign)
(2)Posterior table of the skull disruption: clear CSF leak due to dura matter
rupture
What is the aetiology of the frontal sinus fracture?
(1) MVA
(2) Falls
What is the clinical picture of frontal sinus fracture?
(1)Anterior table of the skull disruption: Frontal depression(the characteristic clinical sign)
(2)Posterior table of the skull disruption: clear CSF leak due to dura matter rupture
Define the ethmoid bone?
one of the 8 bones of the cranium
What is the origin of the word ethmoid?
originates from the Greek ‘ethmos’, meaning sieve
What is the location of the ethmoid bone?
(1) in the midline of the anterior cranium – the superior aspect of the skull that encloses and protects the brain.
(2) at the roof of the nasal cavity
(3) between the two orbital cavities
What is the size of the ethmoid bone?
small
How many ethmoid bones are there in the skull?
1 (unpaired)
What are the functions of the ethmoid bone?
Forms the following:
(1) Medial wall of the orbit
(2) Part of the anterior cranial fossa, where it
separates the nasal cavity (inferiorly) from the
cranial cavity(superiorly)
(3) A significant portion of the: 1) Nasal septum
2) Lateral nasal wall
What is the anatomical structure that is closely related to the ethmoid bone?What is its function in the ethmoid bone?
The olfactory nerve as its numerous nerve fibres pass through the cripriform plate of the ethmoid bone to innervate the nasal cavity with the sense of smell
What is the nerve that is closely related to the ethmoid bone?What is its function in the ethmoid bone?
The olfactory nerve as its numerous nerve fibres pass through the cripriform plate of the ethmoid bone to innervate the nasal cavity with the sense of smell
What are the parts of the ethmoid bone?
Mnemonic;CPE
(1) Cribriform plate
(2) Perpendicular plate
(3) Ethmoidal labyrinth
Discuss cribriform plate?
Define the cribriform plate
A sheet of bone
What is the location of the cribriform plate?
On either side of the crista galli
What is the shape of the cribriform plate?
Sieve like-because it is pierced by
numerous olfactory nerve fibres
What the reason behind the sieve-like shape of the cribriform plate?
because it is pierced by numerous olfactory nerve fibres
What is the characteristic feature of the cribriform plate?
The thinnest part of the anterior cranial fossa and therefore most likely to fracture
What is the function of the cribriform plate?
What are the types of the cribriform plate foramina?what are the structures that are transmitted by these foramina?
What are the structures transmitted by the small cribriform plate foramina and into what place?
Olfactory nerve into the nasal cavity
What is the name of the larger cribriform plate foramina?
2 larger foramina:
(1) Anterior ethmoidal foramen-for anterior ethmoidal vessels and nerve
(2) Posterior ethmoidal foramen-for posterior ethmoidal vessels and nerve
What are the structures transmitted by the large cribriform plate foramina?
2 larger foramina:
(1) Anterior ethmoidal foramen-for anterior ethmoidal vessels and nerve
(2) Posterior ethmoidal foramen-for posterior ethmoidal vessels and nerve
What is the landmark of the ethmoid bone?
Discuss crista galli
Define crista galli
An upward projection
What is the origin of the word crista galli?
Latin for cock’s comb
What is the location of crista galli?
Middle of the ethmoid bone projecting superiorly from the cribriform plate
What is the function of the crista galli?
Attachment of the falx cerberi(sheet of dura matter that separates the two cerebral hemispheres)
Discuss perpendicular plate of ethmoid bone
Define perpendicular plate of ethmoid bone
Projection from crista galli
What is the location of the perpendicular plate of the ethmoid bone?
Descends from the cribriform plate
What is the function of the perpendicular plate of the ethmoid bone?
Forms the superior 2/3rd of the nasal septum
Discuss the ethmoidal labyrinth of ethmoid bone?
Define the ethmoidal labyrinth
Masses
What is the size of the ethmoidal labyrinth?
Large
What is the location of the ethmoidal labyrinth?
On either side of the perpendicular plate
Discuss parts of the ethmoidal labyrinth
Discuss orbital plate of ethmoidal labyrinth
+Definition
Lateral sheet of bone
+Function
Forms the medial wall of the orbit
Define orbital plate of ethmoidal labyrinth
Lateral sheet of bone
What is the function of the orbital plate of ethmoidal labyrinth
Forms the medial wall of the orbit
What is the function of the medial sheet of ethmoidal labyrinth
Forms the upper lateral wall of the nasal cavity, from which the superior and middle conchae extend into the nasal cavity.
Discuss articulations of ethmoid bone
How many bones articulate with the ethmoid bone?
13
What are the types of bones that articulate with the ethmoid bone?
What are the paired bones that articulate with the ethmoid bone?
Mnemonic;No Man Loves Poking inferiorly
(1) Nasal bones
(2) Maxillae
(3) Lacrimal bones
(4) Palatine bones
(5) Inferior nasal conchae
What are the unpaired bones that articulate with the ethmoid bone?
Mnemonic;Falling very severely
(1) Frontal bones
(2) Vomer
(3) Sphenoid bone
What is the clinical relevance of ethmoid bone?
Discuss ethmoid fracture
What is the aetiology of ethmoid fracture?
Discuss clinical picture of ethmoid bone fracture
Discuss fracture of cribriform plate very briefly
Branches of the olfactory bulb fibres may be sheared.This may cause anosmia(loss of sense of smell)
Discuss fracture of the ethmoidal labyrinth very briefly
(1) May allow communication between
the nasal cavity and the orbit
(2) It is then possible for air to enter the
orbit and cause orbital emphysema
Discuss CSF rhinorrhoea very briefly
Define CSF rhinorrhoea
A clear watery discharge from one side of the nose
What is the aetiology of the CSF rhinorrhoea?
What is the pathogenesis of the CSF rhinorrhoea?
What is the treatment of the CSF rhinorrhoea?
Discuss terminology of sphenoid bone
Its name is derived from the Greek‘sphenoeides’, to mean wedge-shaped.
What is the location of the sphenoid bone?
the anterior aspect of the sphenoid
bone lies within the anterior cranial fossa
anteriorly in the cranium
What is the shape of the sphenoid bone?
Butterfly-shaped
What is the feature of the sphenoid bone?
Unpaired bone
Enumerate the anatomical parts of the sphenoid bone?
(1) Body of the sphenoid
(2) Paired greater wings
(3) Paired lesser wings
(4) 2 pterygoid processes
Discuss body of sphenoid bone in details
What is the location of the body of the sphenoid bone?
at the centre of the sphenoid bone
What is the shape of the body of the sphenoid bone?
almost completely cubical in shape
What are the landmarks of the body of the sphenoid bone?
Discuss sphenoidal sinuses of the body of sphenoid bone
are separated by a septum – meaning that the sphenoid body is essentially hollow. The body articulates with the ethmoid bone anteriorly, and it is here that the sinuses open up into the nasal cavity.
What is the reason for hollowness of the body of the sphenoid bone?
Sphenoidal sinuses
Discuss the main landmarks at the superior aspect of the body of the sphenoid bone
What is the terminology of the sella turcica?
Latin for Turkish saddle
Define sella turcica
A bony prominence
What is the shape of sella turcica?
Saddle-shaped depression
What is the function of sella turcica?
Accomadating the pituitary gland,holding and supporting it
Enumerate parts of the sella turcica
(1) Tuberculum sellae(horn of the saddle)
(2) Hypophyseal fossa(pituitary fossa)
(3) Dorsum sellae(back of the saddle)
Discuss parts of sella turcica in details
What is the other name of tuberculum sellae?
Horn of the saddle
Discuss tuberculum sellae in details
Define the tuberculum sellae
A vertical elevation of bone
What is the anatomical significance of the tuberculum sellae?
What is the other name of the hypophyseal fossa?
(1) Seat of the saddle
(2) Pituitary fossa
Define the hypophyseal fossa
A depression in the body of the sphenoid
What is the location of the hypophyseal fossa?
In the middle of the sella turcica
What is the function of hypophyseal fossa?
Holds the pituitary gland
What is the other name of the dorsum sellae?
Back of the saddle
Define dorsum sellae
(1) Large square
(2) Superior projections of sphenoidal body bone
What is the direction of the dorsum sellae?
Upward and forward
What is the function of the dorsum sellae?
(1) Forms the posterior wall of the sella turcica
(2) Separate the middle cranial fossa from the posterior cranial fossa
Discuss anatomical marking of sellae turcica
Define the clinoid processes
The sella turcica is surrounded by the anterior and posterior clinoid processes
What are the types of the clinoid processes?
(1) Anterior clinoid process
(2) Posterior clinoid process
Define the anterior clinoid process
The round ends of the lesser wings
What is the location of the anterior clinoid process?
Arise from the sphenoidal lesser wings
What is the function of the anterior clinoid process?
Define the posterior clinoid process
Are the superolateral projections of the dorsum sellae
What is the function of the clinoid process?
They serve as attachment points for the tentorium cerebelli, a membranous sheet that divides the brain
What is the other name for the chiasmaticus sulcus?
Chiasmatic groove
Discuss chiasmaticus sulcus
Define chiasmaticus sulcus
A depressed groove running transversely between the two optic canals
What is the location of chiasmaticus sulcus?
Between the right and left optic canals
Discuss formation of chiasmaticus sulcus
By the optic chiasm(where the optic nerves partially cross)
How many greater wings are there in the sphenoid bones?
Paired(2)
Discuss greater wings of the sphenoid bone
+Locations
extends from the sphenoid body in a lateral, superiorand posterior direction
+Function
It contributes to three parts of the facial skeleton:
1-Floor of the middle cranial fossa
2-Lateral wall of the skull
3-Posterolateral wall of the orbit
+ 3 Foramina
What is the location of the greater wings of the sphenoid bone?
extends from the sphenoid body in a lateral, superiorand posterior direction
What is the function of the greater wings of the sphenoid bone?
It contributes to three parts of the facial skeleton:
1-Floor of the middle cranial fossa
2-Lateral wall of the skull
3-Posterolateral wall of the orbit
How many foramina are there in the greater wings of the sphenoid bone?
3 foramina
Enumerate foramina of the greater wings of the sphenoid bone?
3 foramina
Discuss foramen rotundum
+Location
(1) In the middle cranial fossa
(2) In the greater wing of the sphenoid bone
(3) Opens into the pterygopalatine fossa
+Function-transmits the
Maxillary branch of the trigeminal nerve(CNV2)
What is the location of the foramen rotundum?
(1) In the middle cranial fossa
(2) In the greater wing of the sphenoid bone
(3) Opens into the pterygopalatine fossa
What is the function of the foramen rotundum?
transmits the:
Maxillary branch of the trigeminal nerve(CNV2)
Discuss foramen ovale
+Location
(1) In the middle cranial fossa
(2) In the greater wing of the sphenoid bone
(3) Opens into the infratemporal fossa
+Function-transmits the
Mnemonics;OVALE
(1) Otic ganglion
(2) V3(mandibular nerve,3rd branch of trigeminal nerve)
(3) Accessory meningeal artery
(4) Lesser petrosal nerve
(5) Emissary veins
What is the location of the foramen ovale?
(1) In the middle cranial fossa
(2) In the greater wing of the sphenoid bone
(3) Opens into the infratemporal fossa
What is the function of the foramen ovale?
transmits the:
Mnemonics;OVALE
(1) Otic ganglion
(2) V3(mandibular nerve,3rd branch of trigeminal nerve)
(3) Accessory meningeal artery
(4) Lesser petrosal nerve
(5) Emissary veins
Discuss foramen spinosum
+ Location
(1) In the middle cranial fossa
(2) In the greater wing of the sphenoid bone
(3) Opens into the infratemporal fossa
+Function-transmits the
(1) Middle meningeal vessels(vein and artery)
(2) Meningeal branch of the mandibular nerve(CNV3)
What is the location of the foramen spinosum?
(1) In the middle cranial fossa
(2) In the greater wing of the sphenoid bone
(3) Opens into the infratemporal fossa
What is the function of the foramen spinosum?
Transmits the
(1) Middle meningeal vessels(vein and artery)
(2) Meningeal branch of the mandibular nerve(CNV3)
How many lesser wings are there in the sphenoid bones?
Paired(2)
Discuss lesser wings of the sphenoid bone
What is the location of the lesser wings of the sphenoid bone?
arises from the anterior aspect of the sphenoid body in a superolateral direction
What is the function of the lesser wings of the sphenoid bone
(1) Separates the anterior cranial fossa from the middle cranial fossa
(2) For orms the lateral border of the optic canal –through which the optic nerve and ophthalmic artery travel to reach the eye.
The medial border of the optic canal is formed by the body of the sphenoid
Discuss foramina of the lesser wings of the sphenoid bone
What is the location of the superior orbital fissure?
(1) In the middle cranial fossa
(2) Gap between the lesser and greater wings of the sphenoid
(3) Opens anteriorly into orbit
What is the shape of the superior orbital fissure?
Slit-like
What is the function of the superior orbital fissure?
How many pterygoid processes are there in the sphenoid bone?
Paired(2)
Discuss pterygoid processes of the sphenoid bone?
What is the location of the pterygoid processes of the sphenoid bone?
descends inferiorly from the point of junction between the sphenoid body and the greater wing
What are the anatomical parts of the pterygoid processes of the sphenoid bone?
(1)Medial pterygoid plate:–
supports the posterior opening of the nasal cavity
(2)Lateral pterygoid plate:–
site of origin of the medial and lateral pterygoid muscles
What is the function of the medial pterygoid plate?
supports the posterior opening of the nasal cavity
What is the function of the lateral pterygoid plate?
site of origin of the medial and lateral pterygoid muscles
What are the functions of the sphenoid bone?
1st/contributes to
(1) middle cranial fossa,
(2) lateral wall of the skull
(3) floor and sides of both orbits
2nd/Muscular attachment
The lateral and medial pterygoid muscles which form some of the muscles of masticationoriginate from the lateral pterygoid plate of the sphenoid bone
Discuss articulations of the sphenoid bone
How many bones articulate with the sphenoid bone?
12
What are the unpaired bones that articulate with the sphenoid bone?
Mnemonic;On Visually Equal Fonts
(1) Occipital bone
(2) Vomer
(3) Ethmoid bone
(4) Frontal bone
What are the paired bones that articulate with the sphenoid bone?
Mnemonic;To Perforate Zygomatic Plane
(1) Temporal bone
(2) Parietal bone
(3) Zygomatic bone
(3) Palatine bone
What is the clinical relevance of the sphenoid bone?
Define endoscopic trans-sphenoidal surgery (ETSS)
the pituitary can be accessed surgically by passing instruments through the sphenoid bones and sinus
What is the indication for the endoscopic trans-sphenoidal surgery(ETSS)?
the usual treatment of choice
for pituitary adenomas
What is the technique for the endoscopic trans-sphenoidal surgery (ETSS)?
What is the advantages of the endoscopic trans-sphenoidal surgery (ETSS)?
allows for the surgical management of pituitary denoma without the need for a more extensive craniotomy
What is the disadvantages(complications)of the endoscopic trans-sphenoidal surgery (ETSS)?
1- CSF rhinorrhoea
2- Meningitis
3- Diabetes inspidus
4- Haemorrhage
5- Visual disturbances
Discuss the features, location, shape, parts, attachments (origin, insertion), nerve supply and action of masseter muscle
What are the features of the masseter muscle?
The most powerful muscle of mastication
What is the location of the masster muscle?
The most superficial muscle of all muscles of mastication,I.e; lies superficial to the :
(1) Temporalis muscle
(2) Both pterygoids muscles
Enumerate muscles of mastication
In the following order:-
What is the function of muscles of mastication??
associated with movements of the jaw (temporomandibular joint).
The muscles of mastication develop from which pharyngeal arch ?
1st pharyngeal arch
What is the innervation of muscle mastication?
innervated by the mandibular nerve (V3) ,a branch of the trigeminal nerve (CN V)
What is the shape of the masseter muscle?
Quadrangular
What are the parts of the masseter muscle?
(1) Superficial
(2) Deep
Discuss temporalis muscle
Origin
(1) Floor of the temporal fossa
(2) Deep surface of temporal fascia
Insertion
(1) Coronoid process (tip, inner surface and anterior
border) of the ramus of mandible
(2) Anterior border or margin of ramus of mandible
almost to last molar teeth
Nerve supply
Two deep temporal nerves from the anterior division or trunk of the mandibular nerve (V3), a branch of the trigiminal nerve (CN V)
Action
(1) Elevation of mandible (closing the mouth)
(2) Retraction of mandible (moving the jaw
posteriorly)
(3) Helps in side to side movement of the lower jaw
during grinding
Clinical significance
The muscle is covered by tough temporal fascia which can be harvested surgically and used to repair a perforated tympanic membrane (an operation known as a myringoplasty).
Discuss attachments of masster muscle
What is the origin of the masseter muscle?
What is the insertion of the masseter muscle?
Into the outer surface of the ramus of the mandible
What is the nerve supply of the masseter muscle?
Masseteric nerve from the anterior division or trunk of the mandibular nerve (V3),a branch of the trigeminal nerve (CN V)
What is the action of the masster muscle?
(1) Elevation of the mandible to close the mouth
(as required during biting)
(2) Protrusion of the mandible
Discuss medial Pterygoid muscle
Shape
Quadrangular
Location
Located inferiorly to the lateral pterygoid
Parts
Two heads:(1) Superficial(smaller)
(2) Deep(larger)
Origin
1st/Superficial head: maxillary tuberosity
2nd/Deep head: medial surface(inner surface)of lateral plate of
pterygoid process (lateral Pterygoid plate)
of sphenoid bone
3rd/Both heads: pyramidal process of palatine bone
Insertion
Both heads attach to the medial surface (inner surface ) of the ramus of mandible:
(1) above the angle of mandible and
(2) below the mandibular foramen.
Nerve supply
Nerve to medial pterygoid, a branch from main trunk of the mandibular nerve (V3), a branch of trigeminal nerve.
Action
• Elevation of mandible to close the mouth
• Protraction (Protrusion) of mandible
• Side to side movement of the mandible , i.e.,along
with ipsilateral, lateral pterygoid pushes the chin to
opposite side
Discuss the lateral pterygoid
Shape
Triangular
Parts:
Two heads: (1) Superior (upper): smaller
(2) Inferior (lower): larger
Origin:
1st/Superior (upper) head: (1) infratemporal crest
and
(2) infratemporal surface
of the greater wing of
the sphenoid.
(2) Inferior (lower) head: lateral surface of lateral
pterygoid plate of the
sphenoid (lateral plate of
pterygoid process of
sphenoid bone)
Insertion
(1)The two heads converge into a tendon which
attaches to the pterygoid fovea on the
front of the neck of mandible.
(2)Some fibres are also inserted into the articular
disc and capsule of the temporomandibular joint (TMJ).
Nerve supply
A branch from the anterior division of the mandibular nerve.
Actions:
1st/Bilateral action – (1) protraction of the mandible
(It has horizontally
orientated muscle fibres,
and thus is the major
protractor)
and
(2) depression of the mandible
or chin to open the mouth;
while doing so, the muscle
pulls the articular disc
forwards.
2nd/Unilateral action – ‘side to side’ movement of the
jaw along with ipsilateral
medial pterygoid muscle, it
pushes the chin to the
opposite side.
Anatomical significance
The lateral pterygoid is the key muscle of infratemporal region because its relations provide the fair idea of the layout of the structures in the infratemporal fossa.
Relations
1st/Superficial relations: Mnemonic;My Routine Tendon Moving
• Masseter
• Ramus of mandible
• Tendon of temporalis
• Maxillary artery
2nd/Deep relations: Mnemonic;My Money Should Deeply Dissect
My Lingual Inferior Medicine
• Mandibular nerve
• Middle meningeal artery
• Sphenomandibular ligament
• Deep head of medial pterygoid
Structures emerging from the
upper border
• Deep temporal nerves
(anterior and posterior deep temporal nerves)
• Masseteric nerve
Structures emerging from its lower border
• Lingual nerve
• Inferior alveolar nerve
• Middle meningeal artery
(in fact passes upward deep to
muscle)
What is the other name for the oral cavity?
Mouth
Define the oral cavity?
The start of the alimentary canal
What is the location of the oral cavity?
Spans between and communicates to
+Anteriorly:to exterior by-oral fissure:
.Definition:guarded by the opening between the upper and lower lips
.Diameter:The diameter of the oral fissure is controlled by
the muscles of the facial expression,
principally,the orbicularis oris
+Posteriorly:to oropharynx by-oropharyngeal isthmus:
.Definition: the opening of the oropharynx
.Guarded on either side by the:Palatoglossal arch
What is the communication of the oral cavity?
Spans between and communicates to
+Anteriorly:to exterior by-oral fissure
.Definition:guarded by the opening between the upper and lower lips
.Diameter:The diameter of the oral fissure is controlled by the muscles of the facial expression,
principally,the orbicularis oris
+Posteriorly:to oropharynx by-oropharyngeal isthmus
.Definition: the opening of the oropharynx
.Guarded on either side by the:Palatoglossal arch
What is the anterior communication of the oral cavity?
communicates anteriorly to exterior by-oral fissure
.Definition:guarded by the opening between the upper and lower lips
.Diameter:The diameter of the oral fissure is controlled by the muscles of the
facial expression,principally,the orbicularis oris
What is the posterior communication of the oral cavity?
Communicates posteriorly to oropharynx by-oropharyngeal isthmus
.Definition: the opening of the oropharynx
.Guarded on either side by the:Palatoglossal arch
What are the function of the oral cavity?
(1) Digestion: receives food, preparing it for digestion in the stomach and small intestines
(2) Communication and speaking: modifies sound produced in the larynx to create a range of sounds
(3) Breathing: acts as an air inlet in addition to the nasal cavity
What are the divisions of the oral cavity?
Divided into two parts by the upper and lower dental arches(formed by the teeth and their bony scaffolding):-
(1) oral vestibule(vestibule of the mouth)
(2) oral cavity proper(mouth proper)
What divides the oral cavity into two parts?
The upper and lower dental arches (formed by the teeth and their bony scaffolding)
What forms the upper and lower dental arches?
teeth and their bony scaffolding
What is the function of the upper and lower dental arches?
Divides the oral cavity into two parts
(1) Oral vestibule (vestibule of the mouth)
(2) Oral cavity proper (mouth proper)
What is the other name for the oral vestibule?
Vestibule of the mouth
Discuss the oral vestibule
+Definition
An outer part
+Location
Situated anteriorly
+Shape
Horse-shoe shaped
+Size
Small
+Boundaries
(1) Externally: Lips and cheeks
(2) Internally: Teeth and gums
+Communication with the
(1) Exterior via the oral fissure
(2) Oral cavity proper(mouth proper) via the space behind the 3rd molar tooth
+Ducts- parotid gland
.Location: (1) On either side
(2) Opens out into the oral vestibule
(3) Opposite the crown of 2nd upper molar tooth
.Function: Secretes salivary juices
Define the oral vestibule
An outer part
What is the location of the oral vestibule?
Situated anteriorly
What is the shape of the oral vestibule?
Horse-shoe shaped
What is the size of the oral vestibule?
Small
What are the boundaries of the oral vestibule?
(1) Externally: Lips and cheeks
(2) Internally: Teeth and gums
What are the boundaries of the oral vestibule externally?
Lips and cheeks
What are the boundaries of the oral vestibule internally?
Teeth and gums
Discuss communication of the oral vestibule
Communicates with the
(1) Exterior via the oral fissure
(2) Oral cavity proper(mouth proper) via the space behind the 3rd molar tooth
How does the oral vestibule communicate with the exterior?
Via the oral fissure
How does the oral vestibule communicates with the oral cavity proper(mouth proper)?
Via the space behind the crown of 2nd upper molar tooth
Discuss the ducts of the glands that open into the oral cavity
parotid gland
.Location: (1) On either side
(2) Opens out into the oral vestibule
(3) Opposite the crown of 2nd upper molar tooth
.Function: Secretes salivary juices
What is the gland that its duct opens into the oral cavity proper?
Parotid gland
What is the location of the gland that opens its duct into the oral cavity proper?
Parotid gland
(1) On either side
(2) Opens out into the oral vestibule
(3) Opposite the crown of 2nd upper molar tooth
What is the function of the parotid gland in relation to the oral cavity proper?
Secretes salivary juices
What is the other name for oral cavity proper?
Mouth proper
Discuss oral cavity proper
Location
Lies posteriorly to the oral vestibule
Boundaries
1st/Roof(above):
I)Hard palate
.Definition:a bony plate
.Location:anteriorly
.Function:separates the nasal cavity from the oral cavity
.Boundaries(mucosa):
(1) Superiorly:respiratory mucosa- ciliated pseudostratified columnar epithelium(CPCE)
(2) Inferiorly:oral mucosa-stratified squamous epithelium (SSE)
.Nerve supply:Branches of the maxillary nerve(CNV2)-
(1)greater palatine nerve
(2)nasopalatine nerve
II)Soft palate
.Definition:
(1) a muscular structure
(2) posterior continuation of the hard palate
.Location:posteriorly
.Function:It acts as a valve that can-
(1)lower to close the oropharyngeal isthmus
(2)elevate to separate nasopharynx from oropharynx
.Nerve supply:lesser palatine nerve-a branch of the maxillary nerve(CNV2)
2nd/Floor(below):
I)Parts
(1)Oral muscular diaphragm
.Structure:comprised of bilateral mylohyoid muscles
.Function:
1)provides structural support to the floor of the mouth
2)pulls the larynx forward during swallowing
(2)Geniohyoid muscle: pulls the larynx forward during swallowing
(3)Tongue:connected to the floor by the frenulum of the tongue
(a fold of oral mucosa)
(4)Salivary glands
-Submandibular ducts
.Location
1)on either side
2)open in the floor of oral cavity proper
3)on the summot of sublingual papilla
-Sublingual ducts
.Number:about a dozen
.Location:
1)on either side
2)open in the floor of oral cavity proper
3)on the sublingual fold in a row
II)Nerve supply:lingual nerve
-a branch of the mandibular division(V3) of the trigeminal nerve
-provides sensory innervation
3rd/On either side(lateral)
I)Teeth
II)Lips
III)Cheeks
-Layers:
(1)skin
(2)superficial fascia containing buccal pad or fat
(3)buccopharyngeal fascia
(4)Buccinator muscle
–Function:the cheeks are formed are formed by the buccinator muscle
–Action:contracts to keep food between the teeth when chewing
–Nerve supply:buccal branches of the facial nerve(CNVII)
(5)submucosa
(6)buccal mucosa
-Nerve supply:buccal nerve-a branch of the mandibular(V3)division of the trigeminal nerve(not to be confused with the buccal branches of the facial nerve)
Contents (Structures present within oral cavity)
• Teeth and gums
• Tongue
• Soft palate
Nerve supply
(1)Sensory innervation of the oral cavity is supplied by the branches of the trigeminal nerve (CN V)
(2)Posterior aspect of the oral cavity is supplied by glossopharyngeal nerve(CNIX)
Clinical relevance-Gag reflex
.Function: protective against foreign bodies touching the posterior aspects of the oral cavity, which are most
innervated by the glossopharyngeal nerve (CN IX).
.Mechanism: When stimulated, a reflex arc leads to
(1)contraction of the pharyngeal musculature and the
(2)elevation of the soft palate.
The efferent nerve in this case is the vagus nerve (CN X).
What is the location of the oral cavity proper?
Lies posteriorly to the oral vestibule
Discuss boundaries of oral cavity proper
Boundaries
1st/Roof(above):
I)Hard palate
.Definition:a bony plate
.Location:anteriorly
.Function:separates the nasal cavity from the oral cavity
.Boundaries(mucosa):
(1) Superiorly:respiratory mucosa- ciliated pseudostratified columnar epithelium(CPCE)
(2) Inferiorly:oral mucosa-stratified squamous epithelium (SSE)
.Nerve supply:Branches of the maxillary nerve(CNV2)-
(1)greater palatine nerve
(2)nasopalatine nerve
II)Soft palate
.Definition:
(1) a muscular structure
(2) posterior continuation of the hard palate
.Location:posteriorly
.Function:It acts as a valve that can-
(1)lower to close the oropharyngeal isthmus
(2)elevate to separate nasopharynx from oropharynx
.Nerve supply:lesser palatine nerve-a branch of the maxillary nerve(CNV2)
2nd/Floor(below):
I)Parts
(1)Oral muscular diaphragm
.Structure:comprised of bilateral mylohyoid muscles
.Function:
1)provides structural support to the floor of the mouth
2)pulls the larynx forward during swallowing
(2)Geniohyoid muscle: pulls the larynx forward during swallowing
(3)Tongue:connected to the floor by the frenulum of the tongue
(a fold of oral mucosa)
(4)Salivary glands
-Submandibular ducts
.Location
1)on either side
2)open in the floor of oral cavity proper
3)on the summot of sublingual papilla
-Sublingual ducts
.Number:about a dozen
.Location:
1)on either side
2)open in the floor of oral cavity proper
3)on the sublingual fold in a row
II)Nerve supply:lingual nerve
-a branch of the mandibular division(V3) of the trigeminal nerve
-provides sensory innervation
3rd/On either side(lateral)
I)Teeth
II)Lips
III)Cheeks
-Layers:
(1)skin
(2)superficial fascia containing buccal pad or fat
(3)buccopharyngeal fascia
(4)Buccinator muscle
–Function:the cheeks are formed are formed by the buccinator muscle
–Action:contracts to keep food between the teeth when chewing
–Nerve supply:buccal branches of the facial nerve(CNVII)
(5)submucosa
(6)buccal mucosa
-Nerve supply:buccal nerve-a branch of the mandibular(V3)division of the trigeminal nerve(not to be confused with the buccal branches of the facial nerve)
Discuss roof of the oral cavity proper
1st/Roof(above):
I)Hard palate
.Definition:a bony plate
.Location:anteriorly
.Function:separates the nasal cavity from the oral cavity
.Boundaries(mucosa):
(1) Superiorly:respiratory mucosa- ciliated pseudostratified columnar epithelium(CPCE)
(2) Inferiorly:oral mucosa-stratified squamous epithelium (SSE)
.Nerve supply:Branches of the maxillary nerve(CNV2)-
(1)greater palatine nerve
(2)nasopalatine nerve
II)Soft palate
.Definition:
(1) a muscular structure
(2) posterior continuation of the hard
palate
.Location:posteriorly
.Function:It acts as a valve that can-
(1)lower to close the oropharyngeal isthmus
(2)elevate to separate nasopharynx from oropharynx
.Nerve supply:lesser palatine nerve-a branch of the maxillary nerve(CNV2)
Discuss the hard palate of the roof of the oral cavity proper
.Definition:a bony plate
.Location:anteriorly in the roof of the oral cavity
.Function:separates the nasal cavity from the oral cavity
.Boundaries(mucosa):
(1) Superiorly:respiratory mucosa- ciliated pseudostratified columnar epithelium(CPCE)
(2) Inferiorly:oral mucosa-stratified squamous epithelium (SSE)
.Nerve supply:Branches of the maxillary nerve(CNV2)-
(1)greater palatine nerve
(2)nasopalatine nerve
Define the hard palate
a bony plate
What is the location of the hard palate?
anteriorly in the roof of the oral cavity
What is the function of the hard palate?
separates the nasal cavity from the oral cavity
What is the other name for the boundaries of the hard palate?
Mucosa
What are the boundaries of the hard palate?
(1) Superiorly:respiratory mucosa- ciliated pseudostratified columnar epithelium(CPCE)
(2) Inferiorly:oral mucosa-
stratified squamous epithelium (SSE)
What is the superior boundary of the hard palate?
respiratory mucosa:
ciliated pseudostratified columnar epithelium(CPCE)
What is the inferior boundary of the hard palate?
oral mucosa:
stratified squamous epithelium (SSE)
Discuss mucosa of the oral cavity proper
(1) Superiorly:respiratory mucosa- ciliated pseudostratified columnar epithelium(CPCE)
(2) Inferiorly:oral mucosa-
stratified squamous epithelium (SSE)
What is the type of mucosa superiorly in the hard palate?
respiratory mucosa:
ciliated pseudostratified columnar epithelium(CPCE)
What is the lining of the respiratory mucosa of the hard palate?
ciliated pseudostratified columnar epithelium(CPCE)
What is the type of mucosa inferiorly in the hard palate?
oral mucosa:
stratified squamous epithelium (SSE)
What is the lining of the oral mucosa of the hard palate?
stratified squamous epithelium (SSE)
What is the nerve supply to the hard palate?
Branches of the maxillary nerve(CNV2):(1) greater palatine nerve
(2) nasopalatine nerve
Discuss the soft palate
.Definition:
(1) a muscular structure
(2) posterior continuation of the hard
palate
.Location:posteriorly
.Function:It acts as a valve that can-
(1)lower to close the oropharyngeal isthmus
(2)elevate to separate nasopharynx from oropharynx
.Nerve supply:lesser palatine nerve-a branch of the maxillary nerve(CNV2)
Define the soft palate
(1) a muscular structure
(2) posterior continuation of the hard
palate
What is the location of the soft palate in the roof of the oral cavity proper?
posteriorly
What is the function of the soft palate?
It acts as a valve that can:
(1)lower to close the oropharyngeal isthmus
(2)elevate to separate nasopharynx from oropharynx
Discuss parts of floor of oral cavity proper
(1)Oral muscular diaphragm .Structure:comprised of bilateral
mylohyoid muscles
.Function:
1)provides structural support to the floor of the mouth
2)pulls the larynx forward during swallowing
(2)Geniohyoid muscle: pulls the larynx forward during swallowing
(3)Tongue:connected to the floor by the frenulum of the tongue
(a fold of oral mucosa)
(4)Salivary glands
-Submandibular ducts
.Location
1)on either side
2)open in the floor of oral cavity proper
3)on the summot of sublingual papilla
-Sublingual ducts
.Number:about a dozen
.Location:
1)on either side
2)open in the floor of oral cavity proper
3)on the sublingual fold in a row
What is the nerve supply of the soft palate?
lesser palatine nerve-a branch of the maxillary nerve(CNV2)
Discuss floor of the oral cavity
2nd/Floor(below):
I)Parts
(1)Oral muscular diaphragm
.Structure:comprised of bilateral mylohyoid muscles
.Function:
1)provides structural support to the floor of the mouth
2)pulls the larynx forward during swallowing
(2)Geniohyoid muscle: pulls the larynx forward during swallowing
(3)Tongue:connected to the floor by the frenulum of the tongue
(a fold of oral mucosa)
(4)Salivary glands
-Submandibular ducts
.Location
1)on either side
2)open in the floor of oral cavity proper
3)on the summot of sublingual papilla
-Sublingual ducts
.Number:about a dozen
.Location:
1)on either side
2)open in the floor of oral cavity proper
3)on the sublingual fold in a row
II)Nerve supply:lingual nerve
-a branch of the mandibular division(V3) of the trigeminal nerve
-provides sensory innervation
What are the layers of the cheek?
(1)skin
(2)superficial fascia containing buccal pad or fat
(3)buccopharyngeal fascia
(4)Buccinator muscle
Discuss oral muscular diaphragm of the roof of the oral cavity proper
.Structure:comprised of bilateral
mylohyoid muscles
.Function:
1)provides structural support to the floor of the mouth
2)pulls the larynx forward during swallowing
What is the structure of the oral muscular diaphragm
Bilateral mylohyoid muscle
What is the function of the oral muscular diaphragm in the floor of oral cavity proper
1)provides structural support to the floor of the mouth
2)pulls the larynx forward during swallowing
Discuss the structures on either side of the oral cavity
3rd/On either side(lateral)
I)Teeth
II)Lips
III)Cheeks
-Layers:
(1)skin
(2)superficial fascia containing buccal pad or fat
(3)buccopharyngeal fascia
(4)Buccinator muscle
–Function:the cheeks are formed are formed by the buccinator muscle
–Action:contracts to keep food between the teeth when chewing
–Nerve supply:buccal branches of the facial nerve(CNVII)
(5)submucosa
(6)buccal mucosa
-Nerve supply:buccal nerve-a branch of the mandibular(V3)division of the trigeminal nerve(not to be confused with the buccal branches of the facial nerve)
Enumerate contents of the oral cavity
Contents (Structures present within oral cavity)
• Teeth and gums
• Tongue
• Soft palate
What is the nerve supply of the oral cavity?
(1)Sensory innervation of the oral cavity is supplied by the branches of the trigeminal nerve (CN V)
(2)Posterior aspect of the oral cavity is supplied by glossopharyngeal nerve(CNIX)
Discuss gag reflex in relation to the clinical relevance of the oral cavity proper
.Function:
protective against foreign bodies touching the posterior aspects of the oral cavity, which are most innervated by the glossopharyngeal nerve (CN IX).
.Mechanism:
When stimulated, a reflex arc leads to
(1)contraction of the pharyngeal
musculature and the
(2)elevation of the soft palate.
The efferent nerve in this case is the vagus nerve (CN X).
What’s the function of the gag reflex?
protective against foreign bodies touching the posterior aspects of the oral cavity, which are most innervated by the glossopharyngeal nerve (CN IX).
.
What is the mechanism of the gag reflex?
When stimulated, a reflex arc leads to
(1)contraction of the pharyngeal
musculature and the
(2)elevation of the soft palate.
The efferent nerve in this case is the vagus nerve (CN X).
What
