Anatomy of the Skull

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Questions and Answers

Which bone does the frontal bone articulate with in an unpaired manner?

Parietal bone

Sphenoid bone

Occipital bone

Ethmoid bone (correct)

How many borders does the parietal bone have?

Four (correct)

Three

Five

Six

Which bony structure does the squamosal border of the parietal bone come into contact with?

Sphenoid bone

Nasal bone

Frontal bone

Greater wing of the sphenoid bone and the squamous and petrous parts of temporal bone (correct)

What is the shape of the sphenoid bone?

Butterfly-shaped Signup and view all the answers

What is the shape of the body of the sphenoid bone?

Cubical Signup and view all the answers

What is the function of the septum in the sphenoid body?

Separates the sphenoidal sinuses Signup and view all the answers

What is located on the superior surface of the sphenoid body?

Sella turcica and chiasmatic groove Signup and view all the answers

What surrounds the sella turcica?

Anterior and posterior clinoid processes Signup and view all the answers

What is the function of the condylar part of the occipital bone?

To serve as an articular surface with the atlas Signup and view all the answers

What is the name of the eminence formed by the grooves on the internal surface of the squamous part of the occipital bone?

Cruciform eminence Signup and view all the answers

What is the name of the bone that articulates with the zygomatic process of the temporal bone?

Zygomatic bone Signup and view all the answers

What is the function of the nuchal lines on the external surface of the occipital bone?

To represent the site of attachment for numerous muscles and ligaments Signup and view all the answers

What is the name of the bone that covers the back of the head?

Occipital bone Signup and view all the answers

What is the name of the groove located on either side of the internal occipital protuberance?

Groove for transverse sinus Signup and view all the answers

How many parts does the occipital bone have?

Three Signup and view all the answers

What is the name of the bone that articulates with the squamous part of the temporal bone?

Parietal bone Signup and view all the answers

Which of the following bones forms the medial wall of the orbit?

Ethmoid bone Signup and view all the answers

What is the function of the olfactory nerve (CN I) in relation to the ethmoid bone?

It innervates the nasal cavity with the sense of smell Signup and view all the answers

Which part of the ethmoid bone forms the roof of the nasal cavity?

Cribriform plate Signup and view all the answers

What is the function of the perpendicular plate of the ethmoid bone?

It forms the superior two-thirds of the nasal septum Signup and view all the answers

How many bones does the ethmoid bone articulate with?

13 Signup and view all the answers

Which of the following bones contains the middle and inner portions of the ear?

Temporal bone Signup and view all the answers

How many constituent parts make up the temporal bone?

5 Signup and view all the answers

What is the function of the temporomandibular joint?

It forms the joint of the jaw Signup and view all the answers

What is the location of the hypoglossal canal?

In the inner side of the condyle base Signup and view all the answers

What passes through the foramen magnum?

Medulla oblongata, accessory nerves, and vertebral arteries Signup and view all the answers

Which bone articulates with the occipital bone anteriorly?

Sphenoid bone Signup and view all the answers

What forms the posterior part of the jugular foramen?

Jugular notch Signup and view all the answers

Which bones articulate with the occipital bone superiorly?

Parietal bones Signup and view all the answers

Which joint is formed by the articulation of the occipital bone and the atlas?

Atlanto-occipital joint Signup and view all the answers

What is the location of the frontal fontanelle?

At the junction of the coronal and sagittal sutures Signup and view all the answers

What is the name of the groove in the midline of the frontal bone that contains the superior sagittal sinus?

Sagittal sulcus Signup and view all the answers

What is the function of the nasal part of the frontal bone?

Serving as an area of articulation for the nasal bones and frontal processes of the maxilla Signup and view all the answers

What is the name of the vessels and nerve that pass through the supraorbital foramen?

Supraorbital vessels and nerve Signup and view all the answers

What is the shape of the orbital part of the frontal bone?

Triangular-shaped flat plate Signup and view all the answers

What is the name of the bone that forms the anterosuperior aspect of the cranium?

Frontal bone Signup and view all the answers

What is the location of the frontal sinuses?

Above the orbits either side of the midline of the face Signup and view all the answers

What is the name of the extension of the sagittal sulcus edges?

Frontal crest Signup and view all the answers

Study Notes

Fontanelles

There are two major fontanelles: frontal (anterior) and occipital (posterior)
Frontal fontanelle is located at the junction of the coronal and sagittal sutures
Occipital fontanelle is located at the junction of the sagittal and lambdoid sutures

Frontal Bone

Forms the anterosuperior aspect of the cranium
Consists of four parts: squamous, orbital, and nasal
Squamous part:
- Largest component of the frontal bone
- External convex surface forms the shape of the forehead
- Internal surface features: sagittal sulcus, frontal crest, and frontal sinuses
Orbital part:
- Comprised of a triangular-shaped flat plate
- Forms the roof of the orbit
- Anterolateral portion consists of the lacrimal fossa
Nasal part:
- Small area that projects inferiorly between the supraorbital margins
- Articulates with the nasal bones and frontal processes of the maxilla
Articulations:
- Unpaired: ethmoid, sphenoid
- Paired: nasal, maxilla, lacrimal, parietal, zygomatic

Parietal Bone

Has four borders that articulate with surrounding skull bones via sutures
Sagittal border: superiorly, articulates with the other parietal bone to form the sagittal suture
Squamosal border: inferiorly, articulates with the greater wing of the sphenoid bone and the squamous and petrous parts of the temporal bone
Frontal border: anteriorly, articulates with the frontal bone
Occipital border: posteriorly, articulates with the occipital bone to form the lambdoid suture

Sphenoid Bone

'Butterfly-shaped'
Comprised of:
- Body
- Greater wings
- Lesser wings
- Two pterygoid processes
Body:
- Contains the sphenoidal sinuses
- Articulates with the ethmoid bone anteriorly
- Superior surface features: sella turcica, chiasmatic groove

Ethmoid Bone

Comprised of:
- Cribriform plate
- Perpendicular plate
- Ethmoidal labyrinth
Cribriform plate:
- Forms the roof of the nasal cavity
- Pierced by olfactory nerve fibers
Perpendicular plate:
- Forms the superior two-thirds of the nasal septum
Ethmoidal labyrinth:
- Contains the ethmoidal air cells (sinuses)
- Comprised of an orbital plate and a medial sheet
Articulations:
- Unpaired: frontal, vomer, and sphenoid bones
- Paired: nasal bones, maxillae, lacrimal bones, palatine bones, and inferior conchae

Temporal Bone

Contributes to the lower lateral walls of the skull
Contains the middle and inner portions of the ear
Articulates with the mandible to form the temporomandibular joint
Squamous part:
- Articulates with the sphenoid bone and the parietal bone
- Zygomatic process articulates with the zygomatic bone to form the zygomatic arch

Occipital Bone

Unpaired bone that covers the back of the head (occiput)
Comprised of three parts: squamous, condylar, and basilar
Squamous part:
- Largest and most posterior portion
- Borders the parietal and temporal bones
- Internal surface features: grooves for dural venous sinuses, cruciform eminence, and internal occipital protuberance
- External surface features: nuchal lines
Condylar part:
- Forms the lateral walls of the foramen magnum
- Articulates with the atlas (at the atlanto-occipital joint)
- Contains the hypoglossal canal
Basilar part:
- Forms the anterior part of the foramen magnum
- Articulates with the temporal and sphenoid bones
Foramen magnum:
- Allows passage of structures to and from the cranial cavity
- Structures that pass through: medulla oblongata, accessory nerves, vertebral arteries
Articulations:
- Parietal bones superiorly to form the lambdoid suture
- Temporal bones laterally to form the occipitomastoid structure
- Sphenoid bone anteriorly
- Atlas (C1) inferiorly at the atlanto-occipital joint

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Description

This quiz covers the structure and bones of the skull, including the fontanelles and frontal bone.