38 Questions
Which bone does the frontal bone articulate with in an unpaired manner?
Ethmoid bone
How many borders does the parietal bone have?
Four
Which bony structure does the squamosal border of the parietal bone come into contact with?
Greater wing of the sphenoid bone and the squamous and petrous parts of temporal bone
What is the shape of the sphenoid bone?
Butterfly-shaped
What is the shape of the body of the sphenoid bone?
Cubical
What is the function of the septum in the sphenoid body?
Separates the sphenoidal sinuses
What is located on the superior surface of the sphenoid body?
Sella turcica and chiasmatic groove
What surrounds the sella turcica?
Anterior and posterior clinoid processes
What is the function of the condylar part of the occipital bone?
To serve as an articular surface with the atlas
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
What is the name of the bone that articulates with the zygomatic process of the temporal bone?
Zygomatic bone
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
What is the name of the bone that covers the back of the head?
Occipital bone
What is the name of the groove located on either side of the internal occipital protuberance?
Groove for transverse sinus
How many parts does the occipital bone have?
Three
What is the name of the bone that articulates with the squamous part of the temporal bone?
Parietal bone
Which of the following bones forms the medial wall of the orbit?
Ethmoid bone
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
Which part of the ethmoid bone forms the roof of the nasal cavity?
Cribriform plate
What is the function of the perpendicular plate of the ethmoid bone?
It forms the superior two-thirds of the nasal septum
How many bones does the ethmoid bone articulate with?
13
Which of the following bones contains the middle and inner portions of the ear?
Temporal bone
How many constituent parts make up the temporal bone?
5
What is the function of the temporomandibular joint?
It forms the joint of the jaw
What is the location of the hypoglossal canal?
In the inner side of the condyle base
What passes through the foramen magnum?
Medulla oblongata, accessory nerves, and vertebral arteries
Which bone articulates with the occipital bone anteriorly?
Sphenoid bone
What forms the posterior part of the jugular foramen?
Jugular notch
Which bones articulate with the occipital bone superiorly?
Parietal bones
Which joint is formed by the articulation of the occipital bone and the atlas?
Atlanto-occipital joint
What is the location of the frontal fontanelle?
At the junction of the coronal and sagittal sutures
What is the name of the groove in the midline of the frontal bone that contains the superior sagittal sinus?
Sagittal sulcus
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
What is the name of the vessels and nerve that pass through the supraorbital foramen?
Supraorbital vessels and nerve
What is the shape of the orbital part of the frontal bone?
Triangular-shaped flat plate
What is the name of the bone that forms the anterosuperior aspect of the cranium?
Frontal bone
What is the location of the frontal sinuses?
Above the orbits either side of the midline of the face
What is the name of the extension of the sagittal sulcus edges?
Frontal crest
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
This quiz covers the structure and bones of the skull, including the fontanelles and frontal bone.
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