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Chapter 7, Part 2
Axial Skeleton
Spine and Ribcage
Fig. 7.28
7 cervical
vertebrae
(C1–C7)
12 thoracic
vertebrae
(T1–T12)
C1
2
3
4
5
6
7
T1
2
3
4
5
6
7
8
9
10
11
12
Posterior Anterior
Posterior arch
of atlas (C1)
Cervical
Vertebra
curvature
prominens
(C7)
Transverse
process
Body
Thoracic
curvature
Fig. 7.28
L1
5 lumbar
vertebrae
(L1–L5)
2
3
Lumbar
curvature
4
5
Sacrum
(5 fused
sacral
vertebrae)
(S1–S5)
S1
2
3
4
5
Coccyx
Sacral
curvature
(4 fused coccygeal
vertebrae)
(Co1–Co4)
Fig. 7.28
• Primary curves form
during fetal development:
– thoracic
– sacral
• Secondary curves appear
after birth:
– cervical curve—3-4 mos.
(baby can hold head up)
– lumbar—1 year (learning to
stand and walk)
C1
2
3
4
5
6
7
T1
2
Posterior
Posterior arch
of atlas (C1)
Vertebra
prominens
(C7)
Anterior
Cervical
curvature
3
4
5
Transverse
process
6
7
8
Body
9
Thoracic
curvature
10
11
12
L1
2
3
4
Intervertebral
foramen
Spinous
process
Lumbar
curvature
5
S1
2
3
4
5
Sacral
curvature
Coccyx
(4 fused coccygeal vertebrae)
(Co1–Co4)
(a) Anterior view
(b) Right lateral view
Kyphosis (“hunchback”)
Lordosis (“swayback”)
Scoliosis
Often results from
osteoporosis, or vertebral
compression fractures
May be caused by osteoporosis,
vertebral compression fractures,
or added abdominal weight
Most common curvature
deformity; caused by abnormal
formation of vertebral arch
and/or body on one side
Fig. 7.29 – Basic vertebral anatomy
Spinous process
Transverse process
Superior articular facet
Lamina
Superior articular process
Pedicle
Vertebral
arch
Vertebral foramen
Spinal cord
location
Body
(a) Superior view
Fig. 7.29 – Basic vertebral anatomy
Body
Transverse process
Intervertebral disc
Superior articular facet
L3
Inferior articular
process of L3
Superior articular
process of L4
L4
Lamina
Spinous process
(b) Posterior view
Inferior articular
process of L4
Fig. 7.29 – Basic vertebral anatomy
Superior articular process of L1
Pedicle
Body
L1
Intervertebral foramen
Intervertebral
disc
L2
Transverse process
Spinous process
Spinal nerve location
L3
Inferior articular process of L3
Inferior articular facet
(c) Lateral view
• Anulus fibrosus
– fibrocartilage
Anulus fibrosus
Nucleus pulposus
• Nucleus
pulposus
– gelatinous
(high water content)
Herniated disc
Pinched left
nerve roots
• Discs together make ~1/4 of
column
• Shock absorbers
• Compressed while
standing/walking
• Stretch back while sleeping (or
doing yoga or Pilates)
Normal right
nerve roots
Superior view of a herniated disc.
Table 7.5a-5
Cervical Vertebrae
Fig. 7.30
Atlas (C1)
Anterior arch
Anterior tubercle
• Named for Atlas,
titan condemned by
Zeus to hold the
heavens on his
shoulders
• Enables you to nod
your head
Superior
articular
facet
Transverse
process
Transverse
foramen
Posterior
tubercle
Posterior arch
Fig. 7.30
Anterior
Dens
Axis (C2)
Superior articular facet
Transverse foramen
Body
Transverse process
Pedicle
Lamina
• Enables you to
turn your head
side to side
Spinous process (bifid)
Posterior
Fig. 7.30
Atlas and axis
Axis of rotation
Atlas
(C1 vertebra)
Transverse
ligament
Axis
(C2 vertebra)
Articular facet for dens
Dens
Axis (C2)
"C2 from top animation small" by Anatomography
"Cervical vertebra 2 close-up top animation" by
Anatomography
14
X-ray of Axis
with dens visible
"Dens axis" by Hellerhoff - Own work. Licensed under CC BY-SA
3.0 via Wikimedia Commons http://commons.wikimedia.org/wiki/File:Dens_axis.jpg#/media/Fil
e:Dens_axis.jpg
15
Table 7.5a-1, Cervical Vertebrae
Transverse
process
Superior
articular facet
Body
Spinal cord
location
Transverse
foramen
Superior articular facet
Transverse
foramen
Body
Bifid spinous
process
Bifid spinous
process
Inferior articular facet
Cervical Vertebra
•
•
•
•
•
Body shaped like kidney bean
No costal articulation for ribs
Spinous process is bifurcated (bifid)
Small transverse processes
Transverse foramen present – provide passage
for arteries and veins to head
• C7, vertebra prominens, can be felt at base of
neck
Cervical vertebra
looks like a fish face
18
Table 7.5a-6
Table 7.5a-2: Thoracic vertebrae
Body
Superior articular facet
Costal
facet
Costal facet
Costal
facet
Superior
articular
facet
Transverse
process
Body
Spinous
process
Spinous
process
Inferior articular facet
Costal
demifacet
Table 7.5a-2: Thoracic vertebrae
• Body shaped like heart
• Costal facets for ribs present
– articulate with head or tubercle of rib
– T11 and T12 lack costal facets on transverse processes
• Costal demifacet
– articulate with edge of head of rib
• No transverse foramen
• Long, slender spinous process
Thoracic vertebra
looks like a giraffe
head
Table 7.5b-3
Lumbar Vertebrae
Table 7.5b-1 Lumbar Vertebra
Transverse process
Body
Body
Spinous
process
Superior
articular
facet
Transverse
process
Inferior articular facet
Spinous process
Table 7.5b-1 Lumbar Vertebra
•
•
•
•
•
Body shaped like oval or circle
No costal facets for ribs present
No transverse foramen
Large, blunt transverse process
Short, blunt spinous process
Lumbar vertebra looks like a
moose head
OsteoMenagerie images from
BoneBrokeBlog.wordpress.com
Fig. 7.31 Sacrum and coccyx
Ala
Base
Superior articular
process
Promontory
S1
S2
Anterior sacral
foramina
S3
Transverse ridges
S4
S5
Apex
Co1
Co2
Co3
Co4
anterior view
Fig. 7.31 Sacrum and coccyx
Sacral canal
Superior
articular facet
Median
sacral crest
Auricular surface
Posterior
sacral foramina
Sacral hiatus
Sacral cornu
Coccygeal cornu
Coccyx
posterior view
Sacrum
• Apex is narrow, pointed portion (inferior)
• Superior end called base
• 5 vertebrae fused
– transverse ridges at horizontal lines of fusion
• superior articular processes at base articulate
with L5
• vertebral canal continues through sacral canal
– terminates in sacral hiatus
• anterior and posterior sacral foramina for
nerves to pelvic organs
sacral
hiatus
Coccyx
• 4 fused vertebrae
– begin to fuse by age 25
• In males, coccyx tilts anteriorly
• In females, coccyx tilts inferiorly
• In old age coccyx may fuse with sacrum
30
Fig. 7.32
Thoracic Cage
Manubrium
Suprasternal notch
Clavicular notch
Costal notch
1
2
True ribs
(1–7)
Sternal angle
3
Body
4
Costal notch
5
6
Xiphoid process
7
False ribs
(8–12)
8
9
12
T12
L1
10 Floating ribs
11
(11–12)
Costal
cartilages
Sternum
Clavicular
notches
Sternum
•
•
•
•
3 parts
Clavicular notches are articulations with clavicles
Suprasternal notch is between clavicular notches
Costal notches are articulations with ribs
– Rib 1 articulates with manubrium
– Rib 2 articulates at sternal angle
– Ribs 3-7 articulate with body of sternum
Manubrium
Sternal
angle
Body
Costal
notches
• Xiphoid process may not ossify until age 40
Sternal foramen
Xiphoid process
Fig. 7.33
Ribs
Head
Crest
Articular facets
for vertebral bodies
Superior
Inferior
Neck
Tubercle
Angle
Articular facet
for transverse process
Junction with
costal cartilage
Costal groove
Shaft
(a) Rib
Fig. 7.33
• Ribs originate on or
between thoracic vertebrae
• Vertebral end of rib
articulates with head of rib
• Head has superior and
inferior articular facets
– articulate with costal facets
on vertebrae
• Tubercle of rib articulates
with costal facet on
transverse process of rib
Costal facet for rib 6
Costal
facet
Costal
demifacet
for rib 6
Rib 6
Tubercle
Neck
Head
T6
(b) Superior view
Fig. 7.32
Thoracic Cage
• Ribs 1-7 are true ribs: articulate
individually with sternum by separate
costal cartilages
• Ribs 8-12 are false ribs: costal cartilages don’t
attach to sternum
– Ribs 8-10: costal cartilages fuse with costal
cartilage of Rib 7
– Ribs 11-12: no connection with sternum, so
called floating ribs
1
2
True ribs
(1–7)
3
4
5
6
7
False ribs
(8–12)
8
9
12
T12
L1
10 Floating ribs
11
(11–12)
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
Fig. 7.34
Parietal
bones
Frontal
bones
Occipital
bone
Zygomatic
bone
Temporal
bone
Maxilla
Nasal bone
Vertebrae
Mandible
Clavicle
Sternum
Scapula
Carpal
bones
Humerus
Metacarpal
bones
Ribs
Phalanges
Radius
Ulna
Femur
Ilium
Tibia
Sacrum
Fibula
Coccyx
Phalanges
Hyaline cartilage
Endochondral ossification center
Intramembranous ossification center
Tarsal
bones
Metatarsal
bones
Fig. 7.35
Fetal development of sternum
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
Sternal bars
8 weeks
9 weeks