Chapter 7 - Axial Skelly Flashcards
What does the cranial cavity enclose?
The brain
What are the orbits?
Eye sockets
What are the paranasal sinuses?
Air-filled spaces connected to nasal cavity
- frontal
- sphenoid
- ethmoidal
- maxillary
What are the functions of the paranasal sinuses?
Decrease skull weight
Resonating chambers
What is the job of your cranial bones?
To protect the brain
What are the two divisions of the cranium?
Calvaria (skullcap) and cranial base (cranial floor)
What are the three divisions of the cranial base?
- anterior cranial fossa (frontal lobe)
- middle cranial fossa (temporal lobe)
- posterior cranial fossa (cerebellum)
Describe the location of the frontal bone
Makes up the forehead
Roof of orbit
Anterior third of roof of cranial cavity
What skull bone is separate in infants but fuses to a single bone by adulthood?
Frontal bone
What is the glabella?
the smooth area above the root of nose
Describe the location of the parietal bones
Cranial roof and part of walls
What are the 4 largest sutures and where are they found?
- Sagittal: between parietal bones
- Coronal: anterior margin (frontal/parietal joint)
- Lambdoid: posterior margin (occipital/parietal joint)
- Squamous: lateral border (parietal/temporal joint)
Describe the location of the temporal bones?
Lateral wall and part of floor of cranial cavity
What are the four main parts of the temporal bones?
- Squamous
- Tympanic
- Mastoid
- Petrous
Describe the squamous part of the temporal bone and what features are found there
Flat/vertical
Encircled by squamous suture
Features: zygomatic process, mandibular fossa
Describe the tympanic part of the temporal bone and what features are found there
Ring that borders the ear canal
Features: external auditory meatus, styloid process
Describe the mastoid part of the temporal bone and what features are found there
Posterior portion
Features: mastoid process (air pockets), mastoid notch, stylomastoid foramen (Facial nerve)
Describe the petrous part of the temporal bone and what features are found there
Cranial floor - “little mtn. range”
Separates middle from posterior cranial fossa
Features: middle- and inner-ear cavities, internal auditory meatus, carotid canal, jugular foramen
Describe the location of the occipital bone?
Rear of skull and base
What is the major foramen found in the occipital bone and what goes through it?
Foramen Magnum
Spinal cord
What are some of the features of the occipital bone?
Foramen Magnum
Occipital condyle (knobs that allow skull to rest of vertebral column)
External occipital protuberance
Superior and inferior nuchal lines
Describe the sphenoid bone
Thick median body with outstretched wings
Describe the lesser wings of the sphenoid bone
Posterior margin of anterior cranial fossa
Posterior wall of orbit
Features: optic canal (optic nerve) - anterior to sella turcica
Describe the greater wings of the sphenoid bone
Approximately half of the middle cranial fossa
Lateral surface
What are some of the features fo the sphenoid bone?
Greater and lesser wings Superior orbital fissure (passage of nerves supplying the eye muscle, between greater/lesser wings) Body (sphenoid sinus) Sella turcica (pituitary gland) 3 major foramen: 1. Foramen rotundum 2. Foramen ovale 3. Foramen spinosum
Describe the location of the ethmoid bone
Between orbits
Contributes to the roof/walls of the nasal cavity, medial wall of orbit, nasal septum
What are some features of the ethmoid bone
Honeycomed with air cells - ethmoid sinus
Perpendicular and orbital plates
Crista galli (attachment for dura matter)
Cribriform plate and foramina
Nasal conch (superior and middle, inferior is it’s own bone)
What bones are considered facial bones (14)?
2 each: maxillae, palatine, zygomatic, lacrimal, nasal, inferior nasal conchae
1 of each: vomer, mandible
What is the purpose of the facial bones?
To shape the face
support internal structures of oral and nasal cavities
Support teeth
Where is the maxillae located and what is its job?
Upper jaw
Supports teeth
Make up the floor and medial walls of the orbit
Forms 4/5ths of the hard palate
What are some features fo the maxillae?
Alveolar process (bony points between teeth) Alveolus (sockets that hold teeth) Inferior orbital fissure Palantine process Maxillary sinus (largest sinus)
Describe the palatine bones and the structures it helps to form
L-shaped
Forms part of nasal cavity wall
Forms part of floor of orbit
Posterior 1/5 of the hard palate
What are the two plates of the palatine bone?
Perpendicular plate and parallel plate
Where are the zygomatic bones found and what structures do they help to form?
Upper cheek bones Forms the angle of cheeks Forms part of the lateral wall fo orbit Inverted T-shape Contribute to the zygomatic arch
Where are the lacrimal bones found?
Part of the medial wall of each orbit
Describe features of the lacrimal bones
Smallest skull bone
Lacrimal sac (foss)
- collect tears from eyes
- drain into nasal cavity
Describe the nasal bones and their jobs
Form bridge of nose
Support cartilages that shape lower portion of the nose
Easily fractured
Describe the vomer and it’s job
Inferior half of the nasal septum (inferior to eh perpendicular plate of ethmoid)
Supports cartilage that forms anterior part of nasal septum
Describe the inferior nasal conchae
Largest of three conchae in the nasal cavity
Not part of the ethmoid bone (other two conchae are)
Describe the location of the mandible and it’s job
Jaw bone
Supports lower teeth
Attachment for the muscles of mastication
What are some features of the mandible?
Alveolar processes (support teeth) Body Ramus Angle Anterior coronoid process Posterior condylar process Mandibular condyles Mental foramen Mandibular foramen (inferior alveolar nerve for tooth sensation)
What are the 7 bones that make up the orbit?
- frontal
- sphenoid
- zygomatic
- maxilla
- lacrimal
- ethmoid
- palatine
What are the bones of the nasal cavity?
Vomer Ethmoid (perpendicular plate) Inferior nasal conchae Frontal Nasal Sphenoid Palantine (horizontal plate) Maxillae (palatine process) Lacrimal bone
What are fontanelles? What are they made of?
Spaces between unfused cranial bones (in infants)
Contain fibrous membrane
What is the purpose of fontanelles?
Allow for shifting of bones during birth and growth of brain
Where is your hyoid bone and what is so special about it?
Between chin and larynx
No articulation with other bones (only bone in body like that)
Suspending from styloid process
Attachment site for muscles that control mandible, tongue, and larynx
What are the three auditory ossicles
Malleus (mallet)
Incus (handle)
Stapes (stirup)
What is the purpose of the vertebral column?
Supports the skull and trunk
Protects spinal cord
Absorbs stress of movement
Provides attachments for limbs, thoracic cage, and postural muscles
How many total vertebrae are there and what are the breakdowns into groups?
33 total (23 cartilaginous intervertebral discs) Breakdown: - 7 cervical - 12 thoracic - 5 lumbar - 5 sacral (fused into sacrum) - 4 coccygeal (fused into coccyx)
What are some general features of a vertebrae?
Body (weight bearing, rough surfaces for attachment to intervertebral discs)
Vertebral foramen (posterior opening)
Vertebral arch (encloses vertebral forament)
- Lamina and pedicles
Vertebral foramen/canal (passage for spinal cord)
Spinous process
Transverse processes
Superior articular facet (on superior articular process)
Inferior articular facet (on inferior articular facet)
Intervertebral foramen (passage for spinal nerves)
What are some special features of cervical vertebrae?
Small and light C2-C6 have forked spinous process Small body, large vertebral foramen Transverse foramen (passage for vertebral artery and vein) Short transverse process
What are some special features of the atlas vertebrae?
C1 - supports head
Ring surrounding large vertebral foramen
No body
Superior articular facets (articulate with occipital condyles of skull)
Inferior articular facets articulate with C2
What are some special features of the axis vertebrae?
C2 - rotation of head
Dens/odontoid process (projects into vertebral foramen of atlas)
First vertebra with spinous process
What is special about vertebra C7?
“Vertebra prominens”
Has a prominent spinous process
Not forked, but really long/big
(The big bump no the back of your neck)
What are some special features of thoracic vertebrae?
T1-T12 - support ribs
Superior/inferior costal facets
Transverse costal facets
Pointed spinous processes angled downward
What are some special features of lumbar vertebrae?
L1-L5
Thick body
Squarish spinous process
Superior articular processes facing medially
Inferior processes facing laterally (resists twisting)
What are the jobs of the intervertebral discs? What are they made of?
Bind adjacent vertebrae together Enhanced flexibility Support the weight of the body Absorb shock Made of: inner gelatinous nucleus pulposus, outer fibrocartilage annulus fibrosus
What is a herniated disc?
When the pulpous of an intervertebral disc oozes out
What are some of the features of the sacral vertebrae
S1-S5, fully fused into sacrum by age 26 Make up posterior wall of pelvic girdle Anterior surface - smooth and concave - 4 lines of fusion - 4 pairs of sacral/pelvic foramina Posterior surface - very rough - median sacral crest - lateral sacral crest - 4 pairs of sacral/pelvic foramina Sacral canal Auricular surface Superior articular process of S1 (articulates with L5)
What are some features of the coccygeal vertebrae?
Four small vertebrae fused into coccyx by age 20-30
Attachment for pelvic floor muscles
What is included in the thoracic cage? What does it do?
Thoracic vertebrae, sternum, and ribs
Jobs:
Encloses lungs, heart, spleen, liver, and kidneys
Attachment for pectoral girdle and upper limbs
What are the three regions fo the sternum?
The breastbone is the bony plate anterior to the heart
- Manubrium - broad/superior portion, contains suprasternal notch and clavicular notches
- Body - longest part, contains sternal angle, where ribs attach
- Xiphoid process - inferior point, attachment for some abdominal muscles
How many ribs do you have and how are they classified?
12 total
Ribs 1-7 are true ribs
Ribs 8-12 and false ribs
Ribs 11-12 are sub classified as floating ribs (no tubercles!)
What are some features of the ribs?
Head (articulates with bodies of thoracic vertebrae)
Neck (narrow portion distal to head)
Tubercle (articulates with transverse costal facet of vertebrae)
Angle
Shaft (costal groove on inferior margin)
