Prac 2: Anatomy of External Skull Flashcards by Alexandra Robinson

Excluding the 32 teeth and 6 auditory ossicles, how many bones are in the skull?

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What types of joints exist between bones of the skull?

All fibrous (sutures) -> which ossify in adults over a variable amount of time

Aside from auditory ossicles, the only non-fibrous joint is the Temporomandibular Joint (TMJ) = Bilateral synovial hinge

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What portion is the neurocranium?

The portion surrounding the brain - more dorsal

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What portion is the facial skeleton?

Anterior and lower portions of the skull

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List the facial bones. Which ones aren’t paired?

Mandible (unpaired)
Vomer (unpaired)
Maxilla (2)
Zygomatic (2)
Lacrimal (2) 
Nasal (2)
Inferior Nasal Concha (2)
Palatine (2)

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Bones of the neurocranium are?

Frontal, Occipital, Parietal (2), Temporal (2), Sphenoid and Ethmoid

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What are the two divisions of the neurocranium?

Calvaria (skull cap)

Cranial Base: Cranial base further divided into Anterior, Middle and Posterior Fossae

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Coronal suture - between which bones?

Frontal and Parietal

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Lambdoid Suture?

Parietal and Occipital

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Sagittal Suture?

Between the 2 parietal bones

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Squamosal Suture?

Arches posteriorly from the pterion, from the temporal squama to the lower border of parietal bone

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What is the Lambda?

Meeting of the sagittal and lambdoid sutures

thus meeting of the two parietal bones and occipittal bone, posteriorly

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What is the Bregma?

Meeting of the Sagittal and Coronal sutures

thus of frontal bone and parietal bones

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What is the vertex?

Highest point of the skull

Formed by 4 bones: Frontal, 2 parietals and the occipital

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What is the Pterion?

Short suture on the lateral side of the skull where the greater wing of the sphenoid articulates with 3 other bones:

Temporal (squamous part)
Frontal
Parietal

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What is the asterion?

At the articulations of the Parietal, Occipital and Temporal Bones - posterolaterally

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What is the nasion?

Meeting of the nasal and frontal bones

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What is the inion?

The most prominent part of the external occipital protuberance

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What are the articulating portions involved in the TMJ?

The head of the condylar proces of mandible
with
Mandibular fossa of temporal bone

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By what type of joint are the teeth attached to the mandible and maxilla?

Gomphoses - fibrous peg-in-socket joints

From teeth to the inferior (mandible) and superior (maxilla) alveolar processes

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Where is the mandibular foramen located? Where does it lead?

Medial aspect of the ramus of mandible

Leads into mandibular canal

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Which nerves and blood vessels are transmitted in the mandibular canal?

Inferior Alveolar Nerve (from V3)

Inferior Alveolar Artery and Vein

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Where is the mental foramen located?

What emerges from here?

Anterolateral aspect of the mandible

Mental nerve and blood vessels (from the mental canal)

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What is the superior nuchal line?

Extends laterally from the external occipital protuberance

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What muscle attaches to the mastoid process of the temporal bone?

The sternocleinomastoid

Where is the mastoid notch? Which muscle attaches here?

Just medial to the mastoid process Posterior belly of digastric muscle attaches here

What are the two parts of the zygomatic bone? With which bones do they articulate?

``` Frontal Process (superiorly) -> with fronal bone Temporal process (posteriorly) -> with temporal bones ```

What structures form the zygomatic arch?

Temporal process of the zygomatic and the zygomatic process of the temporal bone

What is the area above the zygomatic arch? | What is the area below?

Temporal Fossa Infratemporal fossa

Describe the location of the infratemporal fossa

Beneath the zygomatic arch, | deep to the ramus of the mandible

What bones form the anterior opening of the nasal cavity (piriform aperture)?

Maxilla (most) | Nasal bones

What is the sharp projection of the maxilla at the piriform aperture called?

Anterior Nasal Spine

Where is the Lateral Pterygoid Plate located? Which bone does it belong to?

In the infratemporal fossa, posterior to the maxilla Part of sphenoid bone

Where is the pterygomaxillary fissure?

Between the Lateral Pterygoid Plate (in infratemporal fossa, posterior to maxilla) and the Maxilla bone

Where is the Pterygomaxillary fossa?

Located deeply, at the superior end of the Pterygomaxillary fissure (between maxilla and lateral pterygoid plate)

What is Fossa of the Lacrimal Sac?

Large depression at the anterior part of the medial wall of the orbit This opens into the Nasolacrimal Canal -> leads to the nasal cavity

Infraorbital foramen - which nerve traverses this?

Infraorbital Nerve -> of maxillary division of trigeminal

Supraorbital Foramen - which nerve traverses this?

Supraorbital Nerve -> from Frontal Nerve of Opthalmic nerve from Trigeminal Nerve

Where is the apex of the orbit?

Losated Posteriorly/medially on the orbit

Where is the superior orbital fissure?

In apex of the orbit

What nerves and vessels pass through the superior orbital fissure? (hint think nerves to muscles of eye movement...)

CNIII CNIV Branches of Opthalmic Nerve (CNV) CNVI Sympathetic Fibres from the Cavernous Plexus Inferior Division of the Opthalmic Vein (also passes through the inferior orbital fissure)

Where is the optic canal located? What nerve and vessel pass through here?

Just medial/superior to the superior orbital fissure ``` Optic Nerve (CNIII) Opthalmic Artery ```

What passes through the inferior orbital fissure?

Zygomatic branch of maxillary nerve

What bones contribute to the nasal septum?

Inferiorly, the VOMER bone articulates with the Anterior Nasal Spine (of the maxilla). Superiorly, the nasal septum is formed by the PERPENDICULAR PLATE OF ETHMOID BONE Septal cartilage fills the triangular space between these bones

Middle nasal concha is part of which bone?

Ethmoid

Roof of nasal cavity is formed by...?

Cribriform plate of ethmoid bone

What nerve passes through the foramina in the cribriform plate?

Olfactory Nerve CNI

What forms the base of the nasal cavity?

Anteriorly: Palatine Process of Maxilla Posteriorly: Horizontal Plate of the Palatine bone

What specific part of the CNS passes through the Foramen Magnum?

Where the medulla is continuous with the spinal cord

What major arteries, and which CN enter the skull through the foramen magnum?

Vertebral Arteries Posterior and Anterior Spinal Arteries Accessory Nerve CNXI

What is the Basion? | What is its significance?

The most anterior part of the foramen magnum A landmark to emasure cranial height: from basion to bregma

What are the occipital condyles?

The point of articulation of the skull onto the 1st cervical vertebra (atlas)

Where is the hypoglossal canal, and what passes through it?

Superior to the occipital condyles Hypoglossal nerve (CNXII)

Where is the condylar canal?

May be present posterior to the occipital condyle

Which bones contribute to the Clivus?

Clivus = anterior to foramen magnum Formed from: Occipital bone anterior to the foramen magnum Posterior part of the body of sphenoid

What is the Foramen Lacerum?

Located lateral to the anterior part of the Clivus Formed at the junction between the Occipital, Temporal (apex of petrous part) and sphenoid bones. Filled with cartilage in life*

What nerve passes through the stylomastoid foramen?

Facial Nerve | also the stylomastoid artery

What bones contribute to the jugular foramen What vessel and nerves pass through it?

occipital and temporal Internal Jugular vein Meningeal Branches from Occipital and Pharyngeal Arteries Glossopharyngral, Vagus and Accessory Nerves

What passes through the carotid canal? Where is it?

Internal carotid artery Just anterior to the jugular foramen

What bone (and part of that bone) forms the lateral walls of the posterior nasal apertures?

Medial Pterygoid Plates of the Sphenoid Bone

What passes through the foramen ovale?

Mandibular division of trigeminal nerve (CNV3)

What passes through foramen spinosum? What artery is this a branch of?

Middle Meningeal Artery | from maxillary artery, which is from external carotid artery

What is a Metopic Suture?

Failure of the frontal suture to ossify (usually does so by ~4yo).

What is a fontanelle? Why do they occur?

Fibrous tissue yet to ossify between bones of the neurocranium Occur because neurocranium bones develop via intramembranous ossification

What is the site of the anterior fontanelle?

Bregma in v young children

Site of Posterior Fontanelle?

Lambda in v young children

Site of Sphenoidal Fontanelle

Pterion in v young children

Site of Mastoid Fontanelle

Asterion

Which bones contain air sinuses?

Ethmoid air cells Maxillary Sinuses Frontal Sinuses Sphenoid Sinuses

Prac 2: Anatomy of External Skull Flashcards

(69 cards)