Download Ch 5 Power Point - Axial Skeleton

Chapter 5
Axial Skeleton
3 parts: skull, vertebral
column, bony thorax
Skull: cranium and facial – all but
one joined by sutures
• Cranium: 8 large flat bones – 2
paired – rest single
– Frontal
– Parietal (pair)
• Meet at sagittal suture
• Coronal suture – btw
parietal and frontal
– Temporal (pair) – meet parietal at squamous
suture
• External acoustic meatus – canal to
eardrum
• Styloid process – inferior to acoustic
meatus – neck muscle attachment
• Zygomatic process – joins cheek bone
• Mastoid process – posterior and inferior to
acoustic meatus
–Mastoid sinuses – air cavities
• Jugular foramen – allow passage of jugular
vein
– Occipital – joins parietal at lamboid suture
• Foramen magnum – large opening for
spinal cord
• Occipital condyles – sit on 1st vertebra
– Sphenoid bone – butterfly shaped – floor of
cranial cavity
• Sella turcia – depression that holds pituitary
• Foramen ovale – opening for cranial nerve
to mandible
• Optic canal and
superior orbital
fissure – allow
nerves for eye
– Ethmoid bone – anterior to sphenoid
• Roof of nasal cavity and medial walls of
orbits
• Crista galli – outer brain covering attaches
• Cribriform plates – allow nerves through
• Facial: 14 bones – 6 paired – 2 single
– Maxillae (maxillary bones)
• Upper jaw – keystone of face
• Alveolar margin – holds teeth
• Palatine processes – anterior portion of
hard palate
• Paranasal sinuses –
openings – drain
into nasal passage
– Palatine bones
• Posterior to palatine processes
• Posterior part of hard palate
• Failure to fuse = cleft palate
– Zygomatic bones – cheekbones
– Lacrimal bones
• Fingernail size
• Medial wall of orbit
• Grooved for tear
passage
– Nasal bones - bridge of nose
– Vomer – single – nasal septum
– Inferior Nasal Conchae
• Project from lateral walls of nasal cavity
– Mandible – single
• Lower jaw
• Only free movable joint of skull – meets
temporal bones
• Body – horizontal part
• Rami (ramus) –
upright bars
• Hyoid bone
– Suspended in midneck region
• 2cm above larynx
– Held by ligaments – touches
no other bones
– Body and 2 pairs of horns
(greater and lesser)
– Movable base for tongue
• Fetal skull
– Fontanels – soft spots
• allow compression
during birth
Vertebral column (spine)
• Before birth – 33 vertebrae
• 9 fuse to form sacrum and coccyx
• 24 single vertebrae
– 7 cervical – neck
– 12 thoracic – back
– 5 lumbar – lower back
• Vertebrae separated by intervertebral
discs
– Cushion and absorb shock
• Primary curvature
– In thoracic and sacral – present from birth
• Secondary curvature
– Cervical – appears when baby begins to raise
head
– Lumbar – appears when baby begins to walk
• Vertebrae
– Parts
• Body (centrum) – weight bearing – faces
anterior
• Vertebral arch – joining of lamina and pedicle
• Vertebral foramen – canal for spinal cord
• Transverse processes – projection off arch
• Spinal processes –
projection off posterior
• Superior and inferior
articular processes
– Lateral to vertebral
foramen
– Joints w/ other vertebrae
• Cervical – C1 – C7
– 1st – atlas – no body
• Depressions in transverse processes to
receive occipital condyles
• Allow nodding
– 2nd – axis – acts as a pivot
• Dens – pivot point
– All have transverse foramen for cranial nerves
• Thoracic – T1 – T12
– Costal facets – receive ribs
– Have long spinous processes
• Lumbar – L1 – L5
– Short, chunky spinous processes
• Sacrum – 5 fused vertebrae
– Alae – wings – articulate w/ hips
– Median sacral crest – fused
spinous processes
– Sacral foramen – openings
– Sacral canal – for spinal cord – ends @ sacral hiatus
• Coccyx – 3-5 fused vertebrae – tailbone
Bony Thorax – thoracic cavity
• Sternum – breastbone
– Fusion of manubrium, body,
and xiphoid process
– 7 ribs attach
– Jugular notch – upper border
of manubrium
– Sternal angle – where
manubrium and body meet
– Xiphisternal joint – where
body and xiphoid process
meet
– Sternal puncture – w/draw
hematopoietic tissue
• Ribs – 12
– True ribs – 1st 7 – attach to
sternum
– False ribs – next 5
• 3 – attach to ribs by
costal cartilage
• 2 – floating – don’t attach
to anything
– Intercostal space – btw ribs
– filled w/ muscle