Anatomy Quiz: Nervous System and Ears

Questions and Answers

What structure does the falx cerebri attach to?

Crista galli (correct)

Foramen magnum

Pituitary gland

Sella turcica

Which feature is formed by the combination of the pituitary fossa and clinoid processes?

Jugular foramen

Foramen rotundum

Internal acoustic meatus

Sella turcica (correct)

Which foramen is most lateral in the middle cranial fossa and serves the middle meningeal vessels?

Foramen ovale

Foramen lacerum

Foramen spinosum (correct)

Foramen rotundum

What structure is housed within the posterior cranial fossa?

Cerebellum Signup and view all the answers

What forms the lateral third of the external auditory meatus?

Cartilage Signup and view all the answers

Which canal lies anterior to the occipital condyles?

Hypoglossal canal Signup and view all the answers

What is the primary function of the ceruminous glands located in the external auditory meatus?

To secrete wax Signup and view all the answers

Which structure separates the middle ear from the middle cranial fossa?

Plate of bone Signup and view all the answers

Between which two bones is the jugular foramen located?

Petrous temporal and occipital Signup and view all the answers

Which part of the tympanic membrane is associated with the handle of the malleus?

Pars tensa Signup and view all the answers

What does the anterior cranial fossa primarily house?

Frontal lobes Signup and view all the answers

Which foramen lies between the tip of the petrous temporal bone and the sella turcica?

Foramen lacerum Signup and view all the answers

How is the tympanic membrane positioned within the middle ear?

Obliquely downwards and medially Signup and view all the answers

Which part of the external auditory meatus is completed by fibrous tissue?

Posterosuperior segment Signup and view all the answers

What is the most depressed part of the tympanic membrane called?

Umbo Signup and view all the answers

What is the length of the external auditory meatus approximately?

3.0 cm Signup and view all the answers

Which bone primarily forms the floor of the orbit?

Maxilla Signup and view all the answers

Which structure is located posterior to the inferomedial angle of the orbital rim?

Lacrimal fossa Signup and view all the answers

What type of muscles are the extraocular muscles that move the eyeball?

Skeletal muscles Signup and view all the answers

Which group of muscles is responsible for elevating the upper eyelid?

Levator palpebrae superioris Signup and view all the answers

What part of the bony orbit do the four recti muscles attach to?

Back of the bony orbit Signup and view all the answers

Which foramen in the orbital floor is associated with the nasolacrimal duct?

Infraorbital foramen Signup and view all the answers

How many extraocular muscles are there that move the eyeball?

6 Signup and view all the answers

Which bone does NOT contribute to the formation of the medial wall of the orbit?

Frontal bone Signup and view all the answers

What results from abdominal nerve injury in the context of the internal carotid artery?

Lateral rectus paralysis Signup and view all the answers

Where does the nasal cavity extend from and to?

External nares to the internal nares Signup and view all the answers

What contributes to the skeleton of the external nose?

Both bony and cartilaginous structures Signup and view all the answers

What separates the nasal cavity from the anterior cranial fossa?

Cribriform plate of the ethmoid Signup and view all the answers

Which part of the nasal cavity opens into the nasopharynx?

Choanae Signup and view all the answers

What clinical application is associated with the nose and paranasal sinuses?

Sinus infection evaluation Signup and view all the answers

Which structure is traversed by olfactory nerves to reach the olfactory bulb?

Cribriform plate of the ethmoid Signup and view all the answers

What is the main feature of the middle ear related to its anatomy?

Contains the ossicles Signup and view all the answers

Which cranial nerve is responsible for the movement of the superior oblique muscle?

Trochlear Nerve (CN IV) Signup and view all the answers

What is the primary action of the medial rectus muscle?

Adduction of the eyeball Signup and view all the answers

What anatomical structure forms the optic chiasma?

Separation of optic nerves Signup and view all the answers

Which of the following muscles both elevate and abduct the eyeball?

Inferior oblique Signup and view all the answers

How does the oculomotor nerve interact with the ciliary muscle?

It transports parasympathetic axons. Signup and view all the answers

Which cranial nerve is responsible for abduction of the eyeball?

Abducent Nerve (CN VI) Signup and view all the answers

What condition can arise due to increased intracranial pressure affecting the optic nerve?

Papilloedema Signup and view all the answers

From which part of the brain do the axons of the optic nerve originate?

Retina Signup and view all the answers

Study Notes

Cranial Fossae

Crista Galli: Midline projection where the falx cerebri attaches.
Anterior Cranial Fossa: Occupied by the frontal lobes; separated by the cribriform plate for olfactory nerve function.
Middle Cranial Fossa:
- Central portion formed by the sphenoid's body, containing the pituitary fossa for the pituitary gland.
- Sella turcica formed by the pituitary fossa and clinoid processes.
- Houses temporal lobes; contains foramina such as foramen spinosum, foramen ovale, foramen lacerum, foramen rotundum, and superior orbital fissure.
Posterior Cranial Fossa: Contains cerebellum and brainstem; features foramen magnum, jugular foramen, and internal acoustic meatus.

Meninges

Composed of three layers of connective tissue membranes that encase the spinal cord and brain.

Bony Structure of the Orbit

Medial Wall: Primarily formed by the labyrinth of the ethmoid bone.
Lateral Wall: Formed by the zygomatic bone and greater wing of the sphenoid, separating the temporalis muscle from the eye.
Lacrimal Structures: Includes lacrimal fossa for the lacrimal sac and a foramen for the nasolacrimal duct leading to the nasal cavity.

Eye Muscles

Divided into:
- Intraocular Muscles: Ciliary muscle for lens shape adjustments, controlling pupil size.
- Extraocular Muscles: Six muscles that move the eyeball; divided into recti (superior, inferior, medial) and oblique (superior, inferior).
- Levator Palpebrae Superioris: Elevates upper eyelid.
Innervation:
- Oculomotor nerve (CN III) innervates three recti and inferior oblique.
- Trochlear nerve (CN IV) innervates superior oblique.
- Abducent nerve (CN VI) innervates lateral rectus.

Optic Nerve (CN II)

Sensory nerve arising from retinal cells; partially decussates at the optic chiasma.
Surrounding membranes create a subarachnoid space for cerebrospinal fluid.

Oculomotor Nerve (CN III)

Emerges from the midbrain, enters cavernous sinus, and divides into superior and inferior divisions supplying various eye muscles.
Carries parasympathetic fibers for the ciliary muscle and sphincter pupillae.

External Nose and Nasal Cavity

Skeleton: Composed of bony and cartilaginous structures; nasal bones meet centrally.
Nasal Cavity: Extends from external to internal nares, separated from anterior cranial fossa by the cribriform plate.

External Auditory Meatus

Channels sound from auricle to tympanic membrane, about 3 cm long.
Lateral third is cartilaginous; medial two-thirds is bony with a groove for the tympanic membrane attachment.
Lined by skin with hairs and ceruminous glands, producing ear wax.

Middle Ear (Tympanic Cavity)

Hollow space in petrous part of the temporal bone separating from the cranial fossa and jugular fossa.
Tympanic Membrane: Forms lateral wall; cone-shaped, connecting to the malleus, bulging into the cavity.
Divisions of the tympanic membrane include the pars flaccida and pars tensa.

Clinical Applications

Knowledge essential for diagnosis related to the nose, paranasal sinuses, external and middle ear anatomy.

Key Figures

Various anatomical illustrations highlight cranial foramina and features of the auditory structures, enhancing the understanding of their roles in anatomy and function.

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Description

This quiz covers important topics related to the internal carotid artery, the abducent nerve, and their implications on ocular movement as well as the anatomy of the external and middle ear. Test your knowledge on the functions and injuries associated with these structures. Ideal for students studying human anatomy.