1. Axial Skeleton 3 parts: skull, vertebral column, bony thorax
Chapter 5
Axial Skeleton
3 parts: skull, vertebral column, bony thorax

2. 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

3. 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

4. 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

5. 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

6. 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

7. 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

8. 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

9. Hyoid bone Fetal skull 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

10. 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

11. Primary curvature Secondary 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

12. 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

13. 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

14. Sacrum – 5 fused vertebrae
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 – sacral hiatus
Coccyx – 3-5 fused vertebrae – tailbone

15. 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

16. 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