Lecture 12 Flashcards
Major structures of the axial skeleton
- skull
- vertebrae (and discs)
- sternum, ribs and cartilages
- sacrum and coccyx
Yellow
Main Functions of the skull
- protect brain and brain stem
- protect sensory organs
- attachment sites for muscles
What bones does the skull consist of?
• Cranial bones
– Calvaria (external)
– Base (internal)
• Facial bones
How many bones in the skull
22
8 cranial
14 facial
What are the joints of the skull called
Sutures (fibrous joints)
- made of DFCT
- allows some movement but not a lot
Function of sutures
- allow head to squish in child birth
- allows brain to grow
example of sutures dysfunction
(Synostosis = fusion of two or more bones )
Craniosynostosis = premature fusion of cranial sutures
What is craniosynostosis ?
premature fusion of cranial sutures
Where is the pterion?
- menengeal artery underneath
- if there is damage can cause rupture
What are the joints of the skull called? - connect jaw to cranium
Temporomandibular joint
What kind of joint is the tempomandibular joint ?
Synovial condyloid joint
Parts that form the synovial condyliod joint
Articulation between the manipulation fossa and the condole of the mandible
Features of the temporomadibular joint - synovial condyliod joint
- joint capsule
- synovial fluid
- ligaments to strengthen the joint
- articulable disc
To facilitate lots of movement
Features of the mandible
• Condylar process/head articulates with the temporal bone via the TMJ
• Site for muscle attachments (e.g., for chewing, facial expressions)
• Alveolar processes for teeth
Two key muscles of the skull
Temporalis and masseter
How many facial bones are there
14
Singular facial bones
Mandible
Vomer
Paired facial bones
Maxillla
Zygomatic
Palatine
Nasal
Lacrimal
Inferior nasal conchae
What is the bony base of the oral cavity formed by?
Maxilla and mandible
Paired and singular cranial bones
Singular
- frontal
- ethmoid
- sphenoid
- occipital
Paired
- temporal
- parietal
Functions of the cranial bones
- protects the brain
- attachment sites for muscles
What does the frontal bone do?
- Forms the forehead
- contributes to upper margin of each orbital cavity
Features of the frontal bone
• Supraorbital notch/foramen
– contains supraorbital artery, vein, nerve
• Supraorbital ridge/supercilliary arch
– deep to the eyebrows
What does the Supraorbital notch / foramen contain
Contains supraorbital artery, vein, nerve
Where is the supraorbital ridge/supercilliary arch located?
Deep to the eyebrows
What are the margins of the orbital cavities formed by?
Frontal, zygomatic and maxilla bones
What are the walls of the orbital cavities formed by?
Numerous bones
What are the margin of the nasal cavity formed by
Maxilla and nasal bones
Function of orbital cavities
- holds eyeball
- neurvascular structures
What forms the nasal septum
Vomer and ethmoid
What do the parietal bones form
Lateral and superior walls
What attaches to the temporal lines?
Temporalis muscle which elevates the mandible
Features of the temporal bone
- mandibular fossa (for TMJ)
- zygomatic process
- mastoid process
- external acoustic meatus opening (tympanic part)
Function of the mastoid process
Important attachment site for muscles
Function of the external acoustic meatus opening
Opening into the ear
What does the occipital bone form?
The posterior wall
Purpose of the external occipital protuberance and its location
- needed for muscle attachment
- located on the occipital bone
Features of the occipital bone
- posterior and floor of skull
- occipital condyles ( articulate with cervicval spine - C1)
- foramen magnum (large opening at base of skull for passage of spinal cord)
Sphenoid
Floor/base of the skull is divided by prominent ridges of bone into _____
Fossae
4 different fossa of the cranium
- anterior cranial fossa
- middle cranial fossa
- posterior cranial fossa
- pituitary/hypophysial fossa
Functions of the vertebral column
- balances skull
- supports thoracic cavity
- attachment sites for muscles and ligaments
- protects spinal cord
Two sections of spinal curvature
- kyphosis
- lordosis
Kyphosis
- posterior curvature (convex)
- primary
- determined by shape of vertebra
(In sacrum and thoracic spine)
Lordosis
- anterior curvature (concave)
- secondary
- determinded by the shape of vertebrae and discs
(Cerivcal and lumbar)
Development of curves
- allow us to remain upright
- gives as stablility
Movements of the spine
Spine can be defined as a
Flexible rod
How many vertebrae in each region of the spine
• Cervical (7)
• Thoracic (12)
• Lumbar (5)
• Sacral (5)
• Coccygeal (3-4)
Cervical skull is important for supporting
Skull
Thoracic skull is important for supporting
Ribs
Lumbar skull is important for
Weight bearing
Features of the vertebral arch
- posterior
- muscle and ligament attachment
- encloses spinal cord
Features of the vertebral body
- anterior
- weight-barfing
- (intervertebral disc)
Parts of the vertebral arch and what they do
- 2 pedicle : joins to body
- 2 lamina : forms posterior wall of canal
Extensions of the vertebral arch
- spinous process - posterior
- 2 transverse process - lateral
- articular process - 2 superior, 2 inferior
Function of the articular processes (extensions of the vetebral arch)
- two superior
- two inferior
Functions
• Together form the facet/ zygapophysial (Z) joints
• Guide and direct movement
• Orientation differs between regions
Features of the vertebral canal
- formed by connection between adjacent vertebrae and soft tissues
- passage for spinal cord
Features of the intervetebral foramen
- formed by connection between adjacent vertebrae
- spinal nerves exit
Features of intervertebral disc
- separates vertebral bodies
- binds vertebrae
- resists compression
Features of C1 and C2 specialised vertebrae
C1 (atlas)
- no body
- articulates with occipital condyles
- key function is transmits forces from skull to cervical spine
C2 (axis)
- dens
- no disc between C1 and C2
Atlanto-occipital joint
- occipital condyles (convex)
- Atlas (superior facet) (concave)
Primary movement if nodding (small amount if flexion/extention)
