Skull II Anatomy: Norma Basalis Externa & Interna Quiz

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Questions and Answers

Which part of the hard palate is formed by the palatine processes of the maxilla?

Horizontal plate of palatine bone

Alveolar arch

Posterior 1/3

Anterior 2/3 (correct)

Which feature is a projection from the posterior end of the alveolar arch?

Pyramidal process of palatine bone

Posterior nasal spine

Maxillary tuberosity (correct)

Greater palatine foramen

What is the conical projection found at the sharp free posterior border of the hard palate called?

Alveolar arch

Pyramidal process of palatine bone

Maxillary tuberosity

Posterior nasal spine (correct)

What divides the anterior and middle parts of the norma basalis externa?

Line passing along the posterior border of hard palate Signup and view all the answers

Which foramina transmit the right and left greater palatine nerves and vessels?

Greater palatine foramen Signup and view all the answers

Which anatomical feature creates the U-shaped ridge of bone in the hard palate?

Alveolar arch Signup and view all the answers

What divides the anterior part of the hard palate into right and left halves?

Median palatine suture Signup and view all the answers

What lies medial to the last molar tooth?

Greater palatine foramen Signup and view all the answers

What is the function of the choanae in the respiratory system?

They connect the nasal cavity to the throat. Signup and view all the answers

Which structure is located at the base of the skull and allows passage for the spinal cord?

Foramen magnum Signup and view all the answers

Which part of the sphenoid bone is described by the lateral pterygoid plate?

It serves as an attachment point for muscles of mastication. Signup and view all the answers

What is the role of the stylomastoid foramen?

It's a passage for the facial nerve. Signup and view all the answers

Where would you find the mandibular fossa?

On the temporal bone. Signup and view all the answers

What does the lesser palatine foramina transmit?

Lesser palatine nerve and vessels Signup and view all the answers

Which foramen is located adjacent to the carotid canal?

Jugular foramen Signup and view all the answers

Which structure is transmitted through the foramen ovale?

Mandibular nerve Signup and view all the answers

What is transmitted by the foramen spinosum?

Middle meningeal artery Signup and view all the answers

Which bone forms a major part of the bony nasal septum?

Vomer Signup and view all the answers

What is the significance of the pterygoid fossa?

It serves as an attachment for the medial pterygoid muscle. Signup and view all the answers

Which part of the temporal bone includes the mastoid process?

Mastoid part Signup and view all the answers

What does the jugular foramen transmit?

Inferior petrosal venous sinus Signup and view all the answers

Which of the following bones is located anteriorly to the middle part?

Vomer & body of sphenoid bone Signup and view all the answers

Which features are located at the lower end of the medial pterygoid plate?

Pterygoid hamulus Signup and view all the answers

Which nerve is transmitted through the stylomastoid foramen?

Facial nerve Signup and view all the answers

Where does the groove for the cartilaginous part of the pharyngotympanic tube lie?

Between the greater wing of the sphenoid and the petrous part of the temporal bone Signup and view all the answers

Which structure is NOT transmitted through the foramen magnum?

Internal jugular vein Signup and view all the answers

What feature is found on the infratemporal surface of the greater wing of the sphenoid?

Sphenoidal spine Signup and view all the answers

Which of the following is true about the foramen lacerum?

Its upper part transmits the internal carotid artery. Signup and view all the answers

What separates the choanae from each other?

Vomer Signup and view all the answers

Which artery is associated with the inferior orbital fissure?

Infra-orbital artery Signup and view all the answers

Which structure is associated with the mandibular fossa?

Articular eminence Signup and view all the answers

What structure passes through the carotid canal?

Deep petrosal nerve Signup and view all the answers

What is the function of the hypophysial fossa?

It houses the pituitary gland. Signup and view all the answers

Which structure is located anterior to the hypophysial fossa?

Tuberculum sellae Signup and view all the answers

What does the tegmen tympani primarily form?

Roof of the middle ear Signup and view all the answers

Which foramen allows the passage of the maxillary nerve?

Foramen rotundum Signup and view all the answers

Which structure is found posterior to the medial end of the superior orbital fissure?

Foramen rotundum Signup and view all the answers

What structure does the arcuate eminence correspond to?

Elevation from the superior semicircular canal Signup and view all the answers

Where is the prechiasmatic sulcus located?

In front of the tuberculum sellae Signup and view all the answers

Which of the following structures does NOT transmit the oculomotor nerve?

Foramen lacerum Signup and view all the answers

What structure is transmitted through the foramen spinosum?

Middle meningeal artery Signup and view all the answers

Which bony feature is formed by the body of the sphenoid and the basilar part of the occipital bone?

Clivus Signup and view all the answers

The internal auditory meatus is located at which part of the temporal bone?

Petrous part Signup and view all the answers

The sigmoid sulcus extends as what kind of shape from the transverse sulcus?

S-shaped Signup and view all the answers

Which cranial nerves are transmitted through the internal auditory meatus?

Facial and Vestibulocochlear nerves Signup and view all the answers

What is a characteristic feature of the internal occipital protuberance?

It is a median round projection. Signup and view all the answers

Which structure forms a groove along the superior border of the petrous part of the temporal bone?

Superior petrosal sulcus Signup and view all the answers

The posterior cranial fossa is formed by which of the following bones?

Occipital and Sphenoid Signup and view all the answers

Study Notes

Skull II - Norma Basalis Externa & Interna

The external base of the skull (Norma Basalis Externa) is the outer surface of the skull's base.
The inner surface of the skull's base (Norma Basalis Interna) is divided into three cranial fossae: anterior, middle, and posterior.
Norma basalis externa is divided into three parts: Anterior, Middle, and Posterior. These three parts are divided by two imaginary transverse lines:
- Line 1: Runs along the posterior border of the hard palate.
- Line 2: Runs along the posterior border of the foramen magnum.

Anterior Part

Bones: Composed of the hard palate, split into right and left halves separated by the median palatine suture. Each half is further divided:
- Anterior 2/3: Formed by the palatine processes of the maxilla.
- Posterior 1/3: Formed by the horizontal plate of the palatine bone.
Bony features:
- Alveolar arch: A U-shaped ridge holding the sockets for upper teeth roots.
- Posterior nasal spine: A conical projection on the hard palate's posterior border.
- Maxillary tuberosity: A projection from the posterior alveolar arch.
- Pyramidal process of palatine bone: Projects behind the maxillary tuberosity, on the palatine bone.
Foramina:
- Incisive fossa: A small pit with four foramina inside, including two median foramina. These transmit the sphenopalatine nerves. Two lateral foramina transmit greater palatine nerves and vessels.
- Greater palatine foramen: A single foramen on each side, located medial to the last molar tooth, transmits the greater palatine nerve and vessels.
- Lesser palatine foramina: One to three foramina on each side, within the pyramidal process of the palatine bone, transmitting the lesser palatine nerve and vessels.

Middle Part

Bones:
- Vomer and body of the sphenoid bone (anteriorly).
- Pterygoid process of the sphenoid bone, the infratemporal surface of greater wing of sphenoid & squamous part of temporal bone (anterolaterally).
- Petrous, tympanic, and mastoid parts of temporal bone (posterolaterally).
- Basilar and two lateral parts of the occipital bone (posteriorly).
Bony features:
- Choanae (posterior nasal apertures): Separated by the vomer, forming a major part of the bony nasal septum.
- Pterygoid processes: Each has lateral and medial pterygoid plates with a pterygoid fossa between them. The upper end of the medial pterygoid plate has the scaphoid fossa and pterygoid tubercle; the lower end forms the pterygoid hamulus.
- Groove for pharyngotympanic (Eustachian) tube: Lies between the greater wing of the sphenoid and the petrous part of the temporal bone.
- Squamous part of temporal bone: Has the mandibular fossa and articular eminence, crucial for the temporomandibular joint.
- Infratemporal surface of the greater wing of sphenoid bone: Has a sphenoidal spine at its apex and two foramina (foramen ovale and foramen spinosum).
- Inferior orbital fissure: Separates the greater wing of sphenoid bone from the maxilla, contributing to the orbital cavity.
- Petrous part of temporal bone: A wedge-shaped bone with foramen lacerum, rough quadrate area, and carotid canal. The jugular foramen is positioned posterolaterally to the carotid canal.
- Mastoid part of temporal bone: Has a styloid process, mastoid process, mastoid notch, and occipital groove. It includes the stylomastoid foramen, an opening between the mastoid and styloid processes.

Posterior Part

Bones:
- Squamous part of the occipital bone.
Bony features:
- External occipital protuberance
- External occipital crest
- Superior nuchal line
- Inferior nuchal line
- Mastoid emissary foramen

Description of Norma Basalis Interna

The inner surface of the skull's base is divided into three cranial fossae:
- Anterior cranial fossa
- Middle cranial fossa
- Posterior cranial fossa

Anterior Cranial Fossa

Bones: Cribriform plate of ethmoid bone and orbital plates of frontal bone (anteriorly).
Bones: Body and lesser wings of the sphenoid bone (posteriorly)..
Bony features: Frontal crest, cribriform plate, crista galli, body of sphenoid bone(jugum sphenoidale), and anterior clinoid process.
Foramina: Foramen cecum; pores of cribriform plate; Anterior ethmoidal foramen; Posterior ethmoidal foramen.

Middle Cranial Fossa

Bones: Greater wing of sphenoid bone, squamous part of temporal bone, and anterior surface of petrous part of temporal bone.
Bones: Sella turcica (body of sphenoid); made of hypophysial fossa(pituitary fossa); tuberculum sellae and dorsum sellae:
Bony features: Prechiasmatic sulcus, posterior clinoid processes, and petrous part of temporal bone (trigeminal impression, arcuate eminence, and tegmen tympani).
Foramina: Superior orbital fissure, Optic canal, Foramen lacerum, Foramen rotundum, Foramen ovale, Foramen spinosum.

Posterior Cranial Fossa

Bones: Basilar part of the occipital bone, two lateral parts of the occipital bone, posterior surface of petrous part of temporal bone, and mastoid part of temporal bone.
Bony features: Clivus, internal occipital protuberance, internal occipital crest, transverse sulcus, sigmoid sulcus, superior petrosal sulcus, inferior petrosal sulcus.
Foramina: Internal auditory meatus, jugular foramen, anterior condylar foramen, and foramen magnum.

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Description

Explore the anatomical features of the Norma Basalis Externa and Interna of the skull in this quiz. Learn about the divisions of the external base and the three cranial fossae. Test your knowledge on the bony structures and their arrangements.

Skull II - Norma Basalis Anatomy

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