03 The Skull Flashcards
List the eight bones that make up the cranium
occipital, parietal (2), frontal, temporal (2), ethmoid, sphenoid
List the fourteen bones that make up the facial bones
zygomatic (2), lacrimal (2), palatine (2), maxilla (2), vomer, nasal (2), inferior nasal concha (2), mandible
List the six bones that make up the auditory ossicles
malleus (2), incus (2), stapes (2)
What is the function of the skull sutures?
To connect the major cranial bones
What connects the frontal and parietal bones?
The coronal suture
What connects the left and right parietal bones?
The sagittal suture
What connects the parietal and temporal?
Squamous suture
What connects the occipital and parietal?
Lambdoid suture
What is the bone that forms first during birth?
Occipital (L occipio - to begin)
What does the occipital bone form of the skull?
Most of the posterior and base of the skull
What does the occipital bone of the skull articulate with and via which sutures?
The parietal and temporal bones via lamboid and occipitomastoid sutures
What is the foramen magnum and what is it for?
Present in the base of the occipital bone in the cranium and allows the brain to connect with the spinal cord
What part of the occipital bone of the cranium articulate with the atlas?
Occipital condyles
In neonates, the occipital is formed of four parts joined by cartilage. What are these four parts?
- Squamous part 2. Condylar parts (2) 3. Basilar part
At about which age are the four sections making up the occipital bone of the cranium fused?
Six years old
The squamous part of the occipital bone is incompletely divided by…
The left and right mendosal sutures
If the squamous parts do not fuse it leads to the formation of which bone?
The Wormian bone
Where does the Wormian bone present?
Between lamboidal and saggital sutures
What is the Wormian bone present between the lamboidal and saggital sutures called?
The Inca bone or the os incae
Which population is the Inca bone quite prevalent in?
Peruvian populations
Describe the parietal bone.
Paired, forming the superior and lateral aspects of the skull
What bones do the parietal bones articulate with?
The frontal, temporal, occipital and opposite parietal bone
What is special about the superior and inferior temporal lines present on the parietal bones of the cranium?
They mark the origin of the temporalis muscle
What does the frontal bone exist as until birth?
Exists as paired bones
What suture divides the frontal bone until birth?
The metopic suture (metopon - forehead)
What does the frontal bone articualte with?
The paired parietal bones
What suture does the frontal bone articulate with the paired parietal bones via?
The coronal suture
What does the frontal bone form the roof of?
The orbit
What bone forms the deepest part of the skull?
The ethmoid
The ethmoid has a complex shape. It has paired _____ plates lateral to the ______ plate
Cribriform plates lateral to the perpendicular plate
What does the perpendicular plate form related to the nasal septum?
The superior portion of the nasal septum
The lower/anterior part of the nasal septum is described to be
cartilaginous
What are the implications of the lower part of the nasal septum being cartilaginous?
Cocaine being a vasoconstrictor can cause the blood vessels to close - depriving tissue of blood and leading to septal perforation
Why is the temporal bone called what is it - latin for ‘time’?
Because grey hairs typically appear near the temporal bones first
What does the zygomatic process of the temporal bone join with to form what?
The zygomatic process of the temporal bone joins with the zygomatic bone to form the zygomatic arch or the CHEEKBONE (fleeky!)
What does the tympanic region of the temporal bone surround?
The external auditory meatus
What part of the temporal region of the cranium can be used to estimate the sex of the skull?
The mastoid process
What does the styloid process of the temporal region of the skull do?
Acts as attachment for muscles and a ligament supporting the hyoid bone
How would you describe the shape of the sphenoid?
Butterfly shapes
Why is the sphenoid described as being the keystone of the cranium?
Because it articulates with all other cranial bones
How would you describe the structure of the sphenoid?
A central body with three paired processes
What are the three paired processes which make up the sphenoid?
Greater wings, lesser wings and pterygoid processes
What does the superior surface of the sphenoid bear and what is this for?
Sella turcica in which sits the pituitary (hypophysis)
What is the zygomatic bone?
The front part of the cheekbones
How does the zygomatic bone articulate with the zygomatic process of the temporal bone?
Through the zygomatic arch which is the cheekbone
What does the lacrimal bone form?
Part of the medial wall of the orbit
What does the lacrimal bone contain?
The lacrimal fossa
What is the lacrimal fossa for?
Allowing the passage of the lacrimal sac
What is the lacrimal sac?
Part of the passageway allowing tear to drain away from the eye surface to the nasal cavity
Why is the lacrimal bone called what it is?
Lachrymose or tearful from Latin ‘lacrimosus’ - tear-like
The horizontal process of the palatine forms what?
The posterior part of the hard palate
The vertical plate of the palatine lies between which bones?
The sphenoid and the posterior part of the maxilla
Is the palatine invisible in an articulated skull?
YAS
How does the maxilla fuse and to form what?
Medially to form the upper jaw
What bones does the maxilla fuse with?
All facial bones except the mandible
What part of the hard palate does the maxilla form?
The anterior
What does the maxilla carry and what does it form the floor of?
Carries the upper teeth and forms most of the floor of the orbit
Where does the vomer lie and what does it form?
Lies in the nasal cavity and forms posterior and inferior part of nasal septum
Why is it called the vomer?
Vomere = latin for vomit. Vomer is shaped like a plough, which throws up soil
What does the inferior nasal conchae form?
Forms part of the lateral walls of nasal cavity
What is the mandible formed of?
Body and ramus - meeting at mandibular angle
What does the mandiblular condyle articulate with?
The temporal bone
What does the coronoid process of the mandible act as?
The coronoid process is an insertion point for the temporalis muscle - elevates the jaw during chewing
What does the mandibular foramen on the medial surface of the ramus allow?
Allows the passage of the mandibular nerve
What is the mandibular nerve?
A branch of trigeminal nerve and is associated with tooth sensation
Where do dentists inject novocaine to deaden pain?
In the mandibular nerve area
What are ossicles?
The ossicles (also called auditory ossicles) are three bones in either middle ear that are among the smallest bones in the human body.
What bones make up the ossicles?
Malleus, incus and stapes
What is the malleus shaped like and what did it evolve from?
Hammer and evolved from articular
How did the malleus form in mammals?
Formed jaw articulation with quadrate in lineage leading to mammals
What is the incus shaped like and what did it evolve from?
Anvil and evolved from quadrate
What did the incus form articulation with in lineage leading to mammals?
Articular
What is the stapes and why is it known as the stirrup?
One of the bones of the ear ossicles and it resembles the stirrup
What is the stapes known as in non-mammalian vertebrates?
Columella
Why is the hyoid difficult to assign to the skull or to the rest of the axial skeleton?
Because it is the only bone in humans that does not articulate with anything else
Where is the hyoid bone suspended from?
The styloid processes of the temporal bone
What is the hyoid bone suspended by in terms of ligaments?
The stylohyoid ligament
The hyoid bone is frequently fractured during
strangulation lol
Describe the primary dentition
four incisors, two canines and 4 molars - upper teeth. lower teeth, 4 incisors, 2 canines and 4 molars
Describe the permanent dentition
upper teeth - 4I, 2C, 4PM, 6M lower teeth- 4I, 2C, 4PM, 6M
Label the skull homie
Label the following sutures
Label the different parts of the occipital bone
What bone is this?
Parietal
What bone is this?
Ethmoid
What bone is this?
Temporal
What bone is this and what are the labels?
Sphenoid - greater wings, lesser wings and pterygoid processes
What bone is this?
Zygomatic
What bone is this?
Lacrimal
What bone is this?
Palatine
what bone is this?
maxilla
What bone is this
vomer
What bone is this and what does the mc and cp stand for?
mandible and • Mandibular condyle and Coronoid process
What is mf and what is it for?
mandibular foramen passage of mandiublar nerve
What is this bone?
hyoid
What dentition is this and label
What dentition is this and label
