Thoracic cage the vertebra

1. Anatomy of the Thorax, Pelvis and
Back
1
By Addis T.

2. Thorax
The thorax (chest) is the
superior part of the trun
k between the neck and
abdomen
The superior thoracic a
perture bordered by ver
tebra TI, rib I, and the m
anubrium of sternum
The inferior thoracic a
perture bordered by ver
tebra T12, rib 12, the en
d of rib 11, the costal ma
rgin, and the xiphoid pro
cess of sternum By Addis T. 2

3. The Bony Thorax (thoracic cage)
 Sternum
Composed of Manubrium, Body, Xiphoid Process
form anterior boundary with costal cartilages
 Ribs (12 pair)
7 pair True Ribs
3 pair False Ribs
2 pair are floating
 Form lateral boundaries
 Vertebrae
Thoracic(12)
Forms Posterior boundary of the cage
By Addis T. 3

4. The Sternum
Manubrium
Has Jugular (sternal)
notch
Articulats with rib #1 & 2
Articulate with clavicle at
Clavicular facets
Sternal Angle –articulate
2nd rib which is a major
surface landmark used by
clinicians
Body
Articulates with ribs
2-7
Xiphosternal joint
Xiphoid process
Cartilage-calcifies
through time
Partial attachment of
many muscles
By Addis T. 4

5. By Addis T. 5

6. The Ribs
Twelve pairs
Ribs 1-7 attach directly to sternum by separate
costal cartilages - true ribs
Ribs 8-10 attach indirectly to sternum by attaching
to costal cartilages –false immediately above
Ribs 11-12 have no anterior attachments - floating
ribs
By Addis T. 6

7. By Addis T. 7

8. Rib Anatomy
Typical Ribs
(3rd-9th)
Head (2 facets)
Neck
Tubercle
Angle
Shaft
Subcostal Groove
By Addis T. 8

9. 9
By Addis T.

10.  Atypical Ribs (1st , 2nd , 1
0th , 11th & 12th )
 1st rib-short, wider, posse
s subclavian groove , no an
gle
 1st , 10th, 11th -12th articul
ate with only = one vertebr
a (single articular facet)
 #11, 12
– don’t articulate with transve
rse processes (not have tube
rcle), or anteriorly at all,
– very short neck,
– poor/no angle and costal gro
ove
By Addis T. 10

11. By Addis T. 11

12. Vertebral Column
 The vertebral column the main
part of the axial skeleton, which
extends from the cranium (skull
) to the apex of the coccyx.
 Composed of:-
 The vertebrae, IV discs & assoc
iated ligaments.
 The adult vertebral column is 72
-75 cm long
 one quarter is formed by the
IV discs
12
By Addis T.

13. Vertebrae…
 The vertebral column consists of 33 vertebrae arranged in fiv
e regions.
 7 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 4 coccygeal.
 Of the 9 inferior vertebrae,
 the 5 sacral vertebrae are fused in adults to form the sacru
m
 after approximately age 30, the 4 coccygeal vertebrae fuse
to form the coccyx.
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By Addis T.
Significant motion occurs only between 25 superior vertebrae
The vertebrae gradually become larger as the vertebral colum
n descends to the sacrum and then become progressively smal
ler toward the apex of the coccyx

14. Vertebral Column
By Addis T. 14

15. Structure and Function of the Vertebrae
• Vertebras are vary in size but t
heir basic structure is the same.
• Classified as typical and atypic
al
• Typical vertebra consists of
 Vertebral body
 Vertebral arch
 Seven processes
15
By Addis T.

16. Structure and Function of the Vertebrae
Vertebral body:
– Massive and roughly cylindric
al anterior part of the bone
– The size of the vertebral bodies
increases as the column descen
ds, most markedly from T4 inf
eriorly, as each bears progressi
vely greater body weight.
– Separated from above and belo
w by intervertebral discs (IVD
)
– Used for hematopoiesis.
16
By Addis T.

17. Structure and Function of the Vertebrae…
Vertebral arch
– Is U shaped and posterior to th
e vertebral body
– Formed by two pedicles and la
minae
Pedicles: short cylindrical proce
sses, that project posteriorly f
rom the vertebral body to la
minae
Laminae: two flat parts that co
nnects the spinous process a
nd the transverse process of t
he vertebrae
By Addis T. 17

18. Structure and Function of the Vertebrae…
 Seven processes: arise from the
vertebral arch
– Spinous process (1)
– Transverse processes (2)
– Articular processes ( 4)
Function of processes
 Attachment for deep back muscl
e
 Keeping adjacent vertebrae align
ed, i.e. preventing one vertebra fr
om slipping anteriorly on the ver
tebra below.
 Determine type of movement &
weight bearing (temporarily) 18
By Addis T.

19. Vertebral foramen
 Bounderis:
 anteriorly by the posterior surf
ace of the vertebral body
 laterally and posteriorly: the v
ertebral arch.
 Contains the spinal cord and
the roots of the spinal nerves
19
By Addis T.
Structure and Function of the Vertebrae…

20. Structure and Function of the Vertebrae…
Vertebral notches
•are indentations(concavities) on the s
uperior surface and inferior surface of
the pedicle on each side of a vertebra
• The superior and inferior vertebral
notches of adjacent vertebrae and th
e IV discs connecting them form the
intervertebral foramina, in which t
he spinal nerves emerge from the ver
tebral column with their accompanyi
ng vessels.
By Addis T. 20

21. Structure and Function of the Vertebrae…
In general vertebral column
Support the body's weight
Protection
Plays an important role in posture and locomoti
on
By Addis T. 21

22. Regional Characteristics of the Vertebrae
• Each of the 33 vertebrae is unique.
• However, most of the vertebrae have
characteristic features identifying the
m as belonging to one of the five regi
ons of the vertebral column
• e.g. Cervical vertebrae have foramin
a in their transverse processes
22
By Addis T.

23. Cervical Vertebrae
• Cervical vertebrae form the skeleton of the nec
k.
• Smallest of the 24 moveable vertebrae
• are located between the cranium and the thorac
ic vertebrae.
• they bear less weight than do the larger inferio
r vertebrae.
• Although the cervical IV discs are thinner than
those of inferior regions
• Thickness of the disc & horizontal orientation
of the articular facet , small amount of surroun
ding body mass, give high mobility. 23
By Addis T.

24. Cervical Vertebrae
• The most distinctive feature of each cervical v
ertebra is a foramen on transverse process cal
led foramen transversarium (transverse fora
men).
• The vertebral arteries and their accompanyin
g veins pass through the transverse foramina,
except those in C7, which transmit only small
accessory veins.
• The transverse processes has two projections:
– anterior tubercle and
– posterior tubercle By Addis T. 24

25. Cervical Vertebrae
• The tubercles provide attachment f
or a laterally placed group of cervi
cal muscles (levator scapulae and sc
alenes).
• The anterior rami of the cervical s
pinal nerves course initially on th
e transverse processes in grooves f
or spinal nerves between the tube
rcles.
By Addis T. 25

26. Cervical Vertebrae
• There are 4 typical
– (C3-C6) and
• 3 atypical
– C1(atlas), C2(axis) and C7
• Typical cervical vertebra
– Has a bifid spine
– Have foramina in their transverse
processes.
– Transverse process has an anterior
tubercle and a posterior tubercle.
26
By Addis T.

27. C1 (Atlas)
• The Atlas is ring-shaped and supports the s
kull
• No a body & spinous process
• has paired lateral masses that serve the pla
ce of a body by bearing the weight of the cr
anium
• superior articular surfaces articulate with t
wo large cranial protuberances called the o
ccipital condyles and form atlanto-occipita
l joint
• Inferior articular surfuces articulate with b
elow vertebra and form atlanto axial joint
27
By Addis T.

28. C2 (Axis)
• is the strongest of the cervical vertebr
ae
• C1, carrying the cranium, rotates on
C2 (e.g., when a person turns the hea
d to indicate “no”).
• Has superior articular facets, on whi
ch the atlas rotate
• Has blunt tooth-like dens (odontoid
process) which projects superiorly fro
m its body.
28
By Addis T.
• Both the dens and the spinal cord are encircled by the atlas.
• The dens lies anterior to the spinal cord transverse ligamen
t of the atlas is a ligament which passes between the dens a
nd spinal cord
• It has a large bifid spinous process

29. Atypical Cervical vertebrae
C7
 long spinous process.
 Small transverse foramen
 Has prominent unbifid spinous used to count ve
rtebrae
29
By Addis T.

30. 30
By Addis T.

31. The thoracic vertebrae
• are in the upper back and provide attachment for the ribs
• the primary characteristic features of thoracic vertebrae are
– the costal facets on the body of the vertebrae for articula
tion with ribs.
– The middle four thoracic vertebrae (T5–T8) demonstrate
all the features typical of thoracic vertebrae.
– The articular processes of thoracic vertebrae extend verti
cally
– This arc permits rotation and some lateral flexion of the
vertebral column in this region.
– The T1–T4 vertebrae share some features of cervical vert
ebrae, eg. horizontal spinous process that may be nearly
as prominent as that of the C7.
– T1 also has a complete costal facet for the 1st rib and a d
emifacet for the 2nd rib
By Addis T. 31

32. Thoracic Vertebrae…
• Body
– Heart shaped
– one or two costal facets for artic
ulation with head of rib
• Vertebral foramen
– Circular and smaller than those
of cervical and lumbar vertebrae
• Transverse processes
– Long and strong and extend pos
terolaterally
– length diminishes from T1 to T1
2
– have facets for articulation with
tubercle of rib
By Addis T.
32

33. Thoracic Vertebrae
• Articular processes
– Superior facets directed po
steriorly and slightly latera
lly
– inferior facets directed ant
eriorly and slightly mediall
y
• Spinous processes
– Long, slope posteroinferior
ly
– tips extend to level of verte
bral body below
By Addis T. 33

34. Thoracic Vertebrae
Typical: T5-T8
– Body is larger than cervical
; heart shaped
– Spinous process is long an
d sharp, projects inferiorly
– Vertebral foramen is circul
ar
– Contains all the features ty
pical of thoracic vertebrae
34
By Addis T.

35. Lumbar Vertebrae
• The lower back between the thorax & sacrum.
• Large and kidney shaped body when viewed superiorly
• Vertebral foramen is triangular; larger than in thoracic vert
ebrae and smaller than in cervical vertebrae
• The transverse processes project posterosuperiorly as well a
s laterally.
• On the posterior surface of the base of each transverse proce
ss is a small accessory process, which provides an attachme
nt for the intertransversarii muscles.
35
By Addis T.

36. Lumbar Vertebrae…
• Articular processes - The superior articular process directed
medially and the inferior articular facets directed laterally.
• On the posterior surface of the superior articular processes a
re mammillary processes, which give attachment to both the
multifidus and intertransversarii muscles of the back.
• Spinous processes is short thick, and broad
• Vertebra L5 - is the largest of all vertebra.
• It has massive body and transverse processes
By Addis T. 36

37. Sacrum
• Triangular bone
• Formed by the union of 5 sacral
vertebrae
• Indicated as a S1-S5.
• The fusion of the sacral vertebra
e begins ages 20yrs.
• It provides strength and stability
to the pelvis
• Transmits the weight of the body
to the pelvic girdle
37
By Addis T.

38. Sacrum
• Contains Sacral canal is the conti
nuation of the vertebral canal in t
he sacrum.
• Sacral canal contains the bundle
of spinal nerve roots known as th
e cauda equina
• Sacrum also contains four pairs
of sacral foramina for the exit of
the posterior and anterior rami of
the spinal nerves
By Addis T. 38

39. Sacrum
• The pelvic surface of the sacru
m (ventral surface) is smooth a
nd concave
• Four transverse lines on this s
urface from adults indicate wh
ere fusion of the sacral vertebr
ae occurred.
By Addis T. 39

40. Sacrum
• The base of the sacrum is forme
d by the superior surface of the
S1 vertebra
• The anterior projecting edge of t
he body of the S1 vertebra is the
sacral promontory
• The apex of the sacrum, its taper
ing inferior end, has an oval face
t for articulation with the coccyx.
• Female sacrum are shorter, wid
er and more curved between S2
and S3 than a male sacrum
• But the body of the S1 vertebra i
s usually larger in males.
40
By Addis T.

41. Sacrum
• Dorsal surface which is rough an
d convex
• Contains:- median sacral crest, int
ermediate sacral crest & lateral sa
cral crest
• the median sacral crest, represent
s the fused rudimentary spinous
processes of S1-S4; S5 has no spin
ous process.
• The intermediate sacral crests rep
resent the fused articular processe
s
• The lateral sacral crests are the tip
s of the transverse processes of th
e fused sacral vertebrae.
41
By Addis T.

42. Coccyx (Tail bone )
• Triangular bone formed by fusion of the four
rudimentary coccygeal vertebrae.
• The pelvic surface is concave and relatively s
mooth
• Coccygeal cornua is rudimentary articular pr
ocess which articulate with the sacral cornua.
• Co1 is the largest and broadest of all the cocc
ygeal vertebrae
42
By Addis T.
Rudmentery tran
sverse proces
• Not Participate in support of the body weight during standing.
• Provides attachments for muscle and ligaments.

43. Curvatures of the Vertebral Column
• Vertebral column in adults has fo
ur curvatures: cervical, thoracic, l
umbar, and sacral.
• During fetal development, the ve
rtebral column shows a C-shape
d concavity to the ventral
• This persists in adults only in the
thoracic and sacral regions
• Two type of curvature
– Primary curvature
– Secondary curvature 43
By Addis T.

44. Curvatures of the Vertebral Column
 Primary curvatures
• Seen in the thoracic and sacral curvature
s .
• They are primary curvatures that develo
p during the fetal period in relationship
to the fetal position
• the primary curvatures are in the same
direction as the main curvatures of the fe
tal vertebral column and they retained t
hroughout life 44
By Addis T.

45. Curvatures of the Vertebral Column
 Secondary curvatures
• Occur after birth on the cervical and lumba
r vertebrae
• that result from extension from the flexed f
etal position.
• Cervical curvature begins to appear when t
he infant starts to raise the head.
• The lumbar curvature observed when the in
fant starts to walk
• The secondary curvatures begin to appear b
efore birth but well observed after birth 45
By Addis T.

46. PelvicGirdle
• Basin-shaped ring of bones that connects the vertebral co
lumn to the femurs in the thighs
• Functions
Bear the weight of the upper body when sitting and st
anding
Transfer the weight of the upper body from the axial t
o the lower appendicular skeleton for standing and wa
lking
Provide attachment for the powerful muscles
Contain and protect the pelvic viscera and the inferior
abdominal viscera
46

47. The bony pelvis is formed by 4 bones united by 4 joints
Bones: 2 hip bones, sacrum and coccyx
Joints: 2 sacroiliac joints, pubic symphysis and sacrococc
ygeal joint
47

48. Hipbones
The two hip bones are joined at the pubic symphysis anteri
orly and to the sacrum posteriorly at the sacroiliac joints to
form a bony ring, the pelvic girdle
Each hip bone is formed by 3 bones fusing at the acetabul
um (a cup-like articular depression on lateral aspect for the
head of the femur) by a y-shaped cartilage
Begin to fuse at 15-17 years and complete at 20-25 years o
f age
• The 3 bones are:
 Ilium
 Ischium
 Pubis 48

49. 49

50. Ilium
 The superior, flattened, fan-shaped part of the hip bone
 Located superior to the acetabulum
Body
forms the superior part of the acetabulum
joins ischium and pubis at acetabulum
Ala (wing)
bordered superiorly by iliac crest
dorsum feature:- anterior, posterior and inferior glute
al lines (origins of gluteus minimus, medius and max
imus muscles)
50

51. Landmarks of ilium:
Anterior superior ili
ac spine
Anterior inferior ili
ac spine
Posterior superior il
iac spine
Posterior inferior ili
ac spine
Greater sciatic notc
h
51

52. Ischium
• posteroinferior part of hip bone
• has a body and a ramus
• Body
– forms the posterior part of the acetabulum
– joins ilium and superior ramus of pubis to form acetabu
lum
• Ramus
– fuses with the inferior ramus of pubis
– forms part of the inferior boundary of the obturator fora
men
52

53. • Landmarks
 ischial tuberosity
• large posteroinferior
protuberance of the is
chium
• supports body during
sitting
 ischial spine
• small pointed posteri
or projection near the
junction of the ramus
and body
 lesser sciatic notch
53

54. Pubis
• anteromedial part of hip bone
• Forms anterior part of the acetabulum
• angulated bone; has two rami (inferior & superior) and body
Body
– has a symphyseal surface for articulation with the contral
ateral pubis
Rami
– superior pubic ramus: forms anterior part of acetabulum
– inferior pubic ramus: forms part of the inferior boundary
of the obturator foramen
54

55. Landmarks
Pubic crest
• thickening on the anterior part of the body o
f the pubis
• ends laterally as a swelling - pubic tubercle
Pubic arch (sub pubic angle)
• formed by the ischiopubic rami (conjoined infe
rior rami of the pubis and ischium) of the two s
ides
• these rami meet at the pubic symphysis
• their inferior borders define the subpubic angle
55