ANAT241 Lecture 15 - Skull and Vertebral Column Flashcards
what is the axial skeleton?
bones that are along the midline
what are the 5 major structures of the axial skeleton?
skull vertebrae + discs ribs + cartilages sacrum coccyx
what are the 3 functions of the skull?
- protecting the brain and the brainstem
- protecting sensory organs
- attachment site for muscles involved in speech, chewing, eye movement, facial expression
what are sutures?
fibrous joints that are tiny gaps in between bones
what is the coronal suture?
suture that separates the frontal bone from the parietal bones
what is the sagittal suture?
suture that separates the 2 parietal bones
where is the lambdoid suture located?
on the posterior aspect of the skull
what is the lambdoid suture?
suture that separates the parietal bone from the occipital bone
what is the relationship between lambda and the lambdoid suture?
the lambdoid suture is shaped like the symbol lambda (upside down Y)
what is the relationship between age and sutures?
sutures are membraneous when young and will only fuse in the late 20s
what is the fontanelle?
the top part of the skull in a baby that is more like a membrane that will ossify to become solid bone
what is the squamous suture?
the suture that separates the temporal bone and the parietal bone bilaterally
what is the pterion?
the region where the frontal, temporal, parietal and sphenoid bones join together
what is the TMJ?
tempromandibular joint
what is the tempromandibular joint (TMJ)?
the temporal bone of the mandible
what type of joint is the tempromandibular joint (TMJ)?
a synovial joint
what does the articular disc articulate with?
articulates with the mandibular fossa of the temporal bone and the condyle of the mandible below
what is the condylar process?
the part of the mandible that connects with the temporal bone
what is required for the jaw to open?
in order for the jaw to open some type of rotation of the condylar process is required
what is protusion?
the mandible moving forward
what is retraction?
the mandible moving backwards
what is elevation?
the mandible moving up
what is depression? (in terms of the mandible)
the mandible moving down
what is the part of the mandible that moves up during elevation?
the ramus
what is the alveolar arch?
where the teeth are located
what are the 3 features/functions of the mandible?
- it attaches to the temporal bone via the TMJ
- it is a site for muscle attachments (e.g for chewing, facial expressions)
- it has alveolar process for teeth
what is the coronoid process?
where the temporalis muscle attaches to help close the mouth resulting in elevation of the mandible
what is the temporal line?
where muscles attach
what are the 2 divisions of the structure of the skull?
viscerocranium
neurocranium
what does the viscerocranium make up?
makes up the facial skeleton
what is the neurocranium?
the part of the skull that protects the brain
what are the 3 singular bones that make up the viscerocranium?
mandible
ethmoid bone
vomer bone
what are the 6 paired bones that make up the viscerocranium?
maxillae bone zygomatic bone palatine bone nasal bone lacrimal bone inferior nasal conchae
what bone makes up the forehead?
the frontal bone
what are the 4 singular bones that make up the neurocranium?
frontal bone
ethmoidal bone
sphenoidal bone
occipital bone
what are the paired bones that make up the neurocranium?
temporal bones
parietal bones
what does the frontal bone form?
forms the anterior and superior walls
how does the frontal bone articulate with other bones?
articulates with other bones via sutures
what is the supraorbital notch/foramen?
foramen located above the eye socket
what is the orbital?
the cavity of the skull in which the eye and its appendages are situated
what is the function of the supraorbital notch/forameen?
allows the passage of the supraorbital vein, artery and nerve to pass through
what does the supraorbital nerve supply?
supplies skin sensation on the forehead
what is the supraorbital ridge?
the ridge on top of the eyebrows
what bone is the upper jaw?
the maxilla bone
what bone is the lower jaw?
the mandible bone
what is the zygomatic bone?
the cheekbone
what is the projection of zygomatic bone?
the frontal process of the zygomatic bone
what is the projection of the maxilla bone?
maxilla process
what is the temporal projection?
the temporal process of the zygomatic bone
what is the vomer bone?
bone that splits the nasal cavity into left and right
what bone is the side of the neurocranium?
the parietal bone
what bone is the side of the neurocranium?
the occipital bone
what is the projection of the temporal bone to the zygomatic bone?
the zygomatic process of the temporal bone
what does the parietal bones form?
forms the lateral and superior walls
what line does the parietal bones have?
has the temporal lines for the temporalis muscle
what does the parietal bones contribute to?
the pterion
what is the pterion?
a weak part of the skull where multiple bones come together
what 4 things does each temporal bone have?
- a mandibular fossa for TMJ
- mastoid and styloid processes
- zygomatic process
- internal and external acoustic meatus
where is the mastoid process located?
behind the ear
what is the styloid process?
a small needle like projection
what is the external acoustic meatus?
the opening of the ear canal
why is the pterion a weak part of the skull?
because multiple bones join together at this point if it suffers a blow/damage it will have a large effect on the skull
what are the 4 features of the occipital bone?
- forms the posterior and floor of the neurocranium (vault)
- occipital protuberance
- occipital condyles
- forman magnum
what is the function of the occipital proturberance?
for muscle and ligament attachment
what is the function of the occipital condyles?
articulation of the C1 vertebrae
what are the 4 features of the sphenoid bone?
-has greater and lesser wings
-has hypophyseal fossa
-has many foramina
has pterygoid processes
what is the function of having a hypophyseal fossa in the sphenoid bone?
to provide a space for
the pituitary gland
what is the function of having many foramina in the sphenoid bone?
for many nerves and blood vessels to pass through
what is the function of pterygoid processes in the sphenoid bone?
for muscle attachment for muscles involved in side to side jaw movement
what are the muscles involved inside to side jaw movement?
pterygoid muscles
what are the 3 features of the ethmoid bone?
- has a cribriform plate
- crista galli
- ethmoidal air sinuses
what is the function of the cribriform plate of the ethmoid bone?
has perforations/openings for olfactory nerves
what is the function of the crista galli of the ethmoid bone?
it is an attachment site for the dura
what is the dura?
one of the layers that protects the brain
what are the ethmoidal air sinuses of the ethmoid bone?
many tiny air spaces
what are the 4 depressions of the base of the skull?
- anterior cranial fossa
- middle cranial fossae
- hypophyseal fossa
- posterior cranial fossa
what are 3 functions of the vertebral column?
- to protect the spinal cord and spinal nerves
- keep the torso upright and provide attachment to the pelvic girdle for bipedalism
- attachment sites for muscles and ligaments
what are 2 divisions of the vertebral column in terms of mobility?
mobile vertebrae
fused vertebrae
what does the mobile vertebrae consist of?
cervical vertebrae (7) thoracic vertebrae (12) lumbar vertebrae (5)
what does the fused vertebrae consist of?
sacral vertebrae (5) coccygeal vertebrae (3-4)
what are the typical vertebrae?
the lumbar vertebrae
what are the 6 features that compose a typical vertebrae?
- body
- pedicle
- transverse process
- lamina
- spinous process
- articular process
what is the pedicle?
the part of the vertebrae that connects the body to the remaining vertebral arch
what are the 2 types of articular process?
superior and inferior articular process
what are the 4 features of the cervical vertebrae?
- small body
- bifurcated spinous process
- transverse foramina for vertebral artery
- C1 (atlas) and C2 (axis) are specialised
what is the foramen transversium?
the transverse foramen for the vertebral artery that is the main arterial supply to the brain
what is the main arterial supply to the brain?
the vertebral artery
what is the site of ligament attachment of the cervical vertebrae?
the bifid spine
what is the C1 vertebrae?
atlas
what is the relationship between the C1 vertebrae and body of the vertebrae?
the C1 (atlas) vertebrae has no body
what is the C2 vertebrae?
axis
what is the tubercle?
thickened part of a bone
what is the atlantoccipital joint?
the joint between the atlas bone and the occipital bone
what is the function of the atlantoccipital joint?
side to side hip movement
what is the dens?
superior projecting bony element from the C2 (axis) vertebrae
what are the 4 features of the thoracic vertebrae?
- the spinous process points downwards
- has costal facets
- has little movement between 2 adjacent vertebrae
- multiple thoracic vertebrae
what is the function of the costal facets in the thoracic vertebrae?
for superior, inferior and transverse rib attachment and articulation
what is the function of multiple thoracic vertebrae?
allow for more movement
what are the 4 features of the lumbar vertebrae?
- large body
- do not allow much movement
- distal end of the spinal cord ends at L1/L2
- only cauda equina below this level (important site for lumbar puncture)
what is the function of the large body of the lumbar vertebrae?
large body for load bearing to transmit force from the upper body
what is the cauda equinoa?
bundle of spinal nerves at the end of the spinal cord
what is the sacrum?
5 fused vertebrae
what joint does the sacrum form?
forms the sacroiliac joint with the pelvis
what 2 openings does the sacrum have?
sacral canal (superior) sacral hiatus (inferior)
what is the function of the sacral canal of the sacrum?
for the cauda equina to pass through
what is the sacral hiatus of the sacrum?
the inferior opening of the sacral canal
what is the sacrococcygeal symphysis?
a fibrocartilage disc that separates the sacrum and the coccyx
what is the coccyx in humans?
vestigial tail
what is the relationship between the coccyx and age?
the coccyx deteriorates with age and becomes easily fractured
what is the zygapophyseal joint?
a synovial joint between the superior and inferior articular processes of the adjacent vertebrae
what does the zygapophyseal joint form?
forms the invertebral foramen for spinal nerves
what are intervertebral discs found?
found between vertebrae
what does the intervertebral discs consist of?
anulus fibrosus
nucleus pulposus
what is anulus fibrosis?
a fibrous structure
what does the nucleus pulpous contain?
contains lots of water and will deteriorate with age
where are the anterior and poster longitudinal ligaments located?
located anterior and posterior to the vertebral body
where is the ligament flavum located?
located between adjacent lamina
how many vertebrae is the ligament flavum between?
between 2 vertebrae
where does the ligamentum nuchae extend from?
extends from the external occipital protuberance to C7
what is the function of the ligamentum nuchae?
for posterior neck support
what is the supraspinous ligament?
ligament that connects the tip of the spinous processes from C7 vertebrae to the sacrum
what is the ligament between spinous processes?
interspinous ligament
what is whiplash injury?
hyperextension of the neck where the anterior longitudinal ligament is stretched or torn
