Anatomy Lecture - CH6: Axial Division of the Skeletal System

function of axial skeleton

framework that supports/protects organs in the dorsal & ventral body cavities

cranial cavity

aka the cranium; a fluid-filled chamber that supports/protects the brain

the bilateral lobes (2)

parietal & temporal

sagittal suture

separates the left & right parietal bones

lamboid suture

separates the parietal & occipital bones

coronal suture

separates the parietal & frontal bones

squamous suture

separates the parietal & temporal bones

bone area of supra-orbital foramen

frontal bone

bone area of lacrimal groove

lacrimal bone

bone area of the infra-orbital foramen

maxilla

bone area of the mental foramen, mental protuberance, coronoid process

mandible

bone area of the external acoustic meatus, mastoid & styloid process

temporal bone

bone area of the superior & inferior temporal line

parietal bone

make-up of the zygomatic arch

temporal / zygomatic process of zygomatic bone

bone area of the optic canal, superior & inferior orbital fissure

sphenoid bone

bone area of the zygomaticofacial foramen

zygomatic bone

bone area of the crista galli, cribiform plate

ethmoid bone

bone area of the optic canal/nerve, foramen rotundum, lacerum, ovale, spinosum

sphenoid bone

bone area of the internal acoustic meatus

temporal bone

bone area of the hypoglossal canal

occipital bone

composition of the axial skeleton

bones of the skull, thorax, & vertebral column

number/percentage of bones in the axial skeleton

80 bones / 40% of bones in the body

composition of the cranial cavity/cranium

occipital, frontal (2), temporal (2), parietal, sphenoid, & ethmoid

composition of the facial complex

vomer, conchae, nasal, maxilla, mandible, palatine, zygomatic, lacrimal (Van Can Not Make My Pet Zebra Laugh)

the only single bones of the face

vomer & mandible

composition of the ethmoid

cribiform plate, ethmoidal labryinth, & perpendicular plate

the cavity/part that the ethmoid is involved

nasal cavity/nasal septum

paranasal sinuses

interconnected air-filled pockets; ex. frontal, maxillary, sphenoid sinuses, & ethmoidal air cells

functions of paranasal sinuses

make the skull lighter; produce mucus; resonate air for voice production

orbital complex

super orbital fissure, inferior orbital fissure, & optic foramen/canal

the base for muscles that move the tongue & larynx

hyoid bone

how the hyoid is held in place

suspension by stylohyoid ligaments; only bone to not be attached to another bone

fontanelles

areas of incomplete ossification (in babies); fuse later w/ development

composition of vertebral column

26 bones: 24 vertebra, 1 sacrum, 1 coccyx

regions of vertebral column (superior to inferior)

cervical (7), thoracic (12), lumbar (5)

primary (spinal) curves

curves developed before birth; posteriorly sweeping curves of thoracic & sacral regions; allows the abdominopelvic viscera more room

secondary (spinal) curves

curves developed after birth as infant learns to hold up head (cervical) & begins to walk (lumbar); anteriorly sweeping curves of cervical & lumbar regions

intervertebral disc

pads of fibrous cartilage

vertebral arch

sides & back of vertebral foramen that surround part of the spinal cord

walls of the vertebral foramen

pedicles

roof of the vertebral foramen

lamina

junctions between the pedicles & laminae

articular process

space formed from the vertebral foramina & column; the long tunnel that the spinal cord goes through

vertebral canal

side openings between 2 vertebrae; holes for spinal nerves

intervertebral foramen

the cervical vertebrae’s notched spinous processes

bifid process

extra extensions of bone from the vertebral body that attach to the transverse processes

costal processes

hole between the costal & transverse processes

transverse foramina

the atlas

C1; has no body; articulates cranially w/ occipital condyles; allows us to nod yes; fuses w/ body of C2→forms dens

the dens formed by the atlas C1 & axis C2

odontoid processes

the axis

C2; no intervetrbal discs; allows us to shake no

thoracic vertebrae

T1-T12; looks like a giraffe; associated w/ ribs; ribs articulate at the costal/demifacets

lumbar vertebrae

L1-L5; looks like a moose; vertebral bodies here take up the most body weight

thoracic cage

refers to the 12 ribs; can be 13 from L1

functions of thoracic cage

protects its structures; attachment site for the muscles that help w/ respiration, positioning vertebral column, & movement of the pectoral girdle & upper limb

true ribs

ribs 1-7; articulate directly w/ body of sternum

false ribs

ribs 8-12

floating ribs

ribs 11-12

difference between human & non-human ribs

non-human ribs are missing the subcostal groove

most superior part of the sternum

manubrium

middle part of the sternum

the body

most inferior & smallest part of the sternum

xiphoid process