Bones And Muscles Of The Face Flashcards
What are the main components that make up the face and cranium?
The face and cranium are made up of different bones, many of which are rigid and do not allow for any movement.
What is the primary purpose of the bones in the face and cranium?
The bones in the face and cranium form part of the axial system and are primarily present for means of protection.
What system do the bones of the face and cranium belong to?
The axial system.
What are fossae?
Fossae are shallow depressions in bones that house different structures.
What are the three main fossae within the skull?
The three main cranial fossae are the anterior, middle, and posterior fossae, each made up of specific bones.
What is the difference between foramina and fissures?
Foramina are mostly round while fissures are more elongated. Both serve as passageways for structures of the nervous and circulatory systems.
What is the role of the foramen caecum?
Located in the frontal bone, it allows the passage of a vein from the nose to the superior sagittal sinus.
What is the function of the olfactory or cribriform foramina?
These allow for bundles of nerve fibres to pass through, necessary for the sense of smell.
What passes through the optic foramen?
The ophthalmic artery and the second cranial nerve (CNII), which sends visual information from the eye to the brain.
What structures pass through the superior orbital fissure?
The third, fourth, fifth and sixth cranial nerves, which are responsible for eye movement.
What is the significance of the foramen rotundum of the sphenoid bone?
It connects the middle cranial fossa with the pterygopalatine fossa and allows passage of the maxillary nerve.
What nerve is transmitted through the foramen ovale?
The mandibular nerve, responsible for motor axons to the muscles necessary for mastication.
What is the role of the foramen magnum?
It allows communication between the cranial cavity and the spinal canal.
What is the role of the foramen spinosum?
It permits passage of the middle meningeal artery and the meningeal branch of the mandibular nerve.
What is the dura mater?
The dura mater is the tough fibrous membrane covering the brain and lining the inner surface of the skull. It is the outermost of the three meninges that surround the brain and spinal cord.
What structures combine in the foramen lacerum?
Two nerves combine within this triangular hole, creating the nerve of the pterygoid canal, which provides secretomotor innervation to various glands.
What passes through the carotid canal?
The internal carotid artery, one of the major blood supplies to the brain, enters the skull through the carotid canal.
What is the role of the internal acoustic meatus?
It is one end of a passageway that houses the necessary apparatus for hearing and balance. The seventh and eighth cranial nerves enter the skull through this meatus.
What structures pass through the jugular foramen?
The internal jugular vein and the ninth, tenth and eleventh cranial nerves pass through this foramen.
What is the role of the hypoglossal canal?
It allows passage of the twelfth cranial nerve (the hypoglossal nerve), associated with the tongue.
What structures are situated either side of the foramen magnum?
Situated either side are the condyles, each seated upon a process. These processes are referred to as the condylar portions.
What is the primary function of foramina and fissures in the skull?
They serve as passageways through the bones for structures of the nervous and circulatory system to enter and exit the skull.
What important structures are allowed passage through the superior orbital fissure?
The superior orbital fissure allows many important structures to pass to and from the eye, including many of the nerves responsible for eye movement.
How are foramina, fissures and fontanelles similar yet different?
All three are openings or gaps in the bone structure.
Foramina and fissures act as passageways, whereas fontanelles are soft spots in the skull that eventually ossify.
What is the primary function of the bones in the axial system?
Protection.
What structures does the foramen ovale transmit?
The foramen ovale transmits the mandibular nerve, which is responsible for conducting motor axons to the muscles necessary for mastication.
What is significant about the ethmoid bone’s olfactory foramina?
They are essential for the sense of smell, allowing nerve fibres to pass through and make up the cranial nerve I.
What important neurovascular structures does the foramen rotundum connect?
It connects the middle cranial fossa, which houses the pituitary gland, and the pterygopalatine fossa, which houses important neurovascular structures including the maxillary nerve.
What structures pass through the jugular foramen in the temporal bone?
The jugular foramen transmits the internal jugular vein and the ninth, tenth and eleventh cranial nerves.
Which cranial nerves are associated with the internal acoustic meatus?
The seventh and eighth cranial nerves enter the skull through the internal acoustic meatus and are associated with hearing and balance.
What is the function of the foramen magnum in the occipital bone?
It allows communication between the cranial cavity and the spinal canal.
What glands does the nerve of the pterygoid canal, formed in the foramen lacerum, innervate?
The nerve of the pterygoid canal provides secretomotor innervation to the lacrimal, nasal and palatine glands.
Why are fontanelles important in infants?
Fontanelles are soft spots that allow for easier passage through the birth canal and accommodate rapid brain growth in infancy.
What are the paranasal sinuses?
The paranasal sinuses are air-filled spaces located in the skull, which include the maxillary, frontal, sphenoid and ethmoid sinuses.
What is the primary function of the paranasal sinuses?
They connect to the nasal passages and provide a complex network for airflow and drainage.
Which sinuses are the largest among the pairs?
The maxillary sinuses are the largest.
How are the sinuses named?
The sinuses are named based on the part of the skull they are situated in (e.g., maxillary sinuses are in the maxilla).
What are the bones of the cranium classified as?
The bones of the cranium are classified as irregular bones. They are thin, flat plates that collectively protect the brain.
What are the four main types of fontanelles in the cranium?
The four main types of fontanelles are the anterior, posterior, sphenoid and mastoid fontanelles.
Where is the anterior fontanelle located?
At the junction of the frontal bone and the two parietal bones.
Where is the posterior fontanelle located?
Between the two parietal bones and the occipital bone.
What are sutures in the context of the cranium?
Sutures are the articulation points of the cranial bones. They are immoveable, interlocking joints that join all points together.
Which bones does the sagittal suture join?
The two parietal bones.
Which bones does the lambdoid suture mark the borders between?
The lambdoid suture marks the borders between the parietal and occipital bones.
Which bones does the coronal suture separate?
The coronal suture separates the frontal bone and the parietal bone.
Which bones does the squamous suture join?
The squamous suture joins the parietal bone and the temporal bone.
What is the function of the fontanelles and sutures in a newborn?
The fontanelles and sutures allow for the limited space of the birth canal and facilitate brain growth. They eventually fuse to form a protective helmet for the brain.
What sutures are found in the inferior view of the cranium?
Median palatine,
Transverse palatine,
Petro-occipital,
Spheno-occipital,
Petrosquamous,
Petrotympanic
Where is the frontal bone located and what does it form?
It is located at the front of the head and forms the forehead.
What is the role of the occipital bone?
The occipital bone is situated at the rear of the skull, sits atop the atlas vertebra, and supports the whole head. It is also the route through which blood carrying oxygen to the brain is ferried.
What is the function of the Atlanto-occipital joint?
The Atlanto-occipital joint allows for the movement of the head. It is one of the only three synovial joints within the head.
How are the sphenoid and ethmoid bones unique in their positioning?
These bones sit within the skull but only their ends are visible from an external view. The sphenoid bone articulates with twelve other bones and is butterfly-shaped.
What do the parietal bones form?
The parietal bones form most of the side walls of the cranium.
What are the three prominent markings on the temporal bones?
The external acoustic meatus
The styloid process
The mastoid process.
What is the role of the external acoustic meatus?
It is an opening that leads to the organs of the inner ear.
What is the function of the styloid process?
It is a thin projection where muscles and ligaments of the neck are attached.
What is the function of the mastoid process?
The mastoid process is a wide projection that serves as another attachment point for neck muscles.
What is another role played by bone processes besides muscle attachment?
Another role played by bone processes is to fit into a depression on another bone, forming a joint.
Aside from the Atlanco-occipital joint, what are the only other 2 synovial joints within the head?
Where are they and what is their function?
Temporomandibular Joint (TMJ): This joint is located between the temporal bone of the skull and the mandible. It allows for the opening, closing and lateral movement of the jaw, and is essential for functions like speaking and chewing.
Zygomaticotemporal Joint: This joint is less commonly mentioned but is located between the zygomatic bone and the temporal bone. While it doesn’t provide as much movement as the TMJ, it is still considered a synovial joint.
Describe the Mandible:
Location
Features
Function
Location: Lower part of the skull, beneath the maxilla
Features: Largest, strongest, and only movable bone of the face; connected to the temporal bones by the temporomandibular joints
Function: Forms the lower jaw and supports the entrances to the digestive and respiratory tracts
Describe the Maxilla
Location
Features
Function
Location: Directly above the mandible
Features: Fixed in position, articulates with most facial bones
Function: Forms the upper jaw and supports the entrances to the digestive and respiratory tracts
Describe the Palatine bones
Location
Features
Function
Location: Behind the maxilla
Features: United to form the posterior palate
Function: Supports and protects the nasal cavity and oral cavity
Describe the Nasal bones
Location
Features
Function
Location: Top of the nose, forming the bridge
Features: Small and paired
Function: Provide shape to the nose and protect the nasal cavity
Describe the Inferior nasal concha
Location
Features
Function
Location: Inside the nose, below the nasal bones
Features: Shell-shaped
Function: Increase the surface area of the nasal cavity, aiding in humidifying and filtering air.
Describe the Vomer
Location: Lower part of the nasal septum
Features: Single bone, flat
Function: Divides the nasal cavity into two nostrils
Describe the lacrimal bones
Location
Features
Function
Location: Inner edges of the orbits of the eyes
Features: Most fragile of all facial bones
Function: House the lacrimal apparatus, which aids in tear production and drainage
Describe the Zygomatic bones
Location
Features
Function
Location: Cheek area
Features: Connected to the zygomatic process of the temporal bone and the temporal process of the zygomatic bone
Function: Form the cheekbones and contribute to the orbit of the eye
Define the zygomatic arch
Location
Features
Function
Location: Extension of the zygomatic bones
Features: Formed by processes of two connected bones (zygomatic and temporal)
Function: Provides shape and contour to the face, also an attachment site for muscles
Define the hyoid bone
Location: In the neck
Features: U-shaped, does not articulate with any other bone
Function: Supports the floor of the mouth and the tongue, crucial for human speech
Describe the Zygomatic Process of Temporal Bone
Location
Features
Function
Location: Side of the skull, extending towards the zygomatic bone
Features: Long, arched process
Function: Helps to form the zygomatic arch and provides an attachment for muscles of the jaw and cheek
Describe the Temporal Process of Zygomatic Bone
Location
Features
Function
Location: Extends from the zygomatic bone towards the temporal bone
Features: Flat, pointed
Function: Joins with the zygomatic process of the temporal bone to complete the zygomatic arch
Describe the Nasal Septal Cartilage
Location
Features
Function
Location: Between the nostrils, part of the nasal septum
Features: Composed of cartilage rather than bone
Function: Separates the two nasal passages and provides shape to the nose
Describe the ethmoid bone
Location
Features
Function
Location: At the roof of the nasal cavity, between the two orbits
Features: Light, spongy bone that contributes to the nasal septum and the medial walls of the orbits
Function: Provides support for the nasal cavity and orbits, houses the olfactory apparatus
Using the mnemonic
The Man Made Pies, (Lovely Pies)
List the muscles of mastication
Describe each one separately followed by the function of the group.
Temporalis: Elevates the mandible, originates in the temporal fossa
Masseter: Major jaw muscle, originates in the zygomatic bone
Medial Pterygoid: Quadrilateral muscle
Lateral Pterygoid: Two-headed muscle, inserts into the temporomandibular joint
Functions
• Protrusion (protraction) • Retraction • Elevation • Depression • Rotation
Using the Mnemonic: Old Zoos Can Be Pretty Dull,
List the muscles of facial expression with their individual functions.
Orbicularis Oculi: Surrounds the eyelids
Zygomaticus: Raises the corners of the mouth
Corrugator Supercilii: Draws eyebrows down and together
Buccinator: Compresses the cheek
Platysma: Tenses the skin of the neck
Depressor Labii: Lowers the lower lip
Overall function:
Various movements of the face, eyes, and mouth to produce facial expressions.
Using the mnemonic: Don’t Pick Nose
List the muscles of the nose along with their functions
Dilator Nares: Opens the nostrils
Procerus: Lowers the medial eyebrow, wrinkles the nose
Nasalis: Compresses the bridge, depresses the nostrils
Overall Function:
Control the nostrils and contribute to expressions involving the nose.
Using the mnemonic: Fred Owns Two Apples,
List the muscles of the scalp and there functions
Frontalis: Raises eyebrows and wrinkles the forehead
Occipitalis: Retracts the scalp
Temporalis: Elevates and retracts the mandible
Auricular muscles: Surround the ear
Overall Function:
Movement of the scalp and ears.
