The document provides information on the structure and components of the thorax. It discusses the bones that make up the thoracic cage including the ribs, sternum, and thoracic vertebrae. It describes the joints that connect these bones, including costovertebral, costotransverse, and sternocostal joints. The document also outlines the landmarks of the thorax, the shape of the thoracic cavity, and the openings at the superior and inferior aspects.

1. V.BHASKER
MPT(CT)
NIMS

2. INTRODUCTION
 Thorax (Latin chest) forms the upper part of the trunk
of the body.
 The trunk of the body is divided by the diaphragm into
an upper part, called the thorax, and a lower part,
called the abdomen .
 The thorax is supported by a skeletal framework,
thoracic cage.
 The thoracic cavity contains the principal organs of
respiration-the lungs and of circulation-the heart both
of which are vital for life.

3. COMPONENTS OF THORACIC CAGE:
Sternum
Manubrium, Body (Gladiolus), Xiphoidprocess
Ribs
7 True Ribs
5 False Ribs (including 2 floating ribs)
Clavicle
Scapula
Pectoral
girdle
12Thoracic Vertebrae (T1- T12)

5. SURFACE LAND MARKS OF THORAX
Bony land
marks
Soft tissue
land marks

6. Bony land marks
 Supra sternal or jugular notch
 Sternal angle/angle of Louis
 Xiphisternal joint
 Costal cartilages
 Ribs
 Thoracic vertebral spines

7. Soft Tissue land marks
 The nipple
 Apex beat
 Mid clavicular line/mammary plane
 Mid axillary line
 Scapular line

10. Skeleton of Thorax
 Also known as thoracic cage
 Formation
 Anteriorly – Sternum
 Posteriorly – 12 Thoracic vertebrae& intervening inter
vertebral disc
 On each side by 12 ribs with therir cartilages

11. Shape of Thorax
 Resembles a truncated cone which is narrow above
and broad below
 Narrow upper end is continuous with the root of neck
 The broad lower end is almost completely separated
from the abdomen by Diaphragm

13. Superior aperture/ Inlet of Thorax
 Viscera
Trachea, oesophagus, apices of the lungs with pleura,
remains of the thymus
Large vessels
Brachiocephalic artery on right side.
Left carotid artery and left subclavian artery on left side
Right&Left brachiocephalic veins
Smaller veins
1 Right and left internal thoracic arteries. 2 Right and left
supedor intercostal arteries. 3 Right and left first posterior
intercostal veins. 4 Inferior thyroid veins.

14.  Nerves
1 Right and left phrenic nerves. 2 Right and left vagus
nerves. 3 Right and left sympathetic trunks. 4 Right
and left first thoracic nerves as they ascend across the
first rib to join the brachial plexus.
Muscles
Sternohyoid, sternothyroid and longus colli.

15. Inferior aperture/Outlet of thorax
 Diaphragm of the Outlet of Thorax The outlet is
closed by a large musculo-tendinous partition, called
the diaphragm-the thoraco-abdominal diaphragm-
which separates the thorax from the abdomen.
 Large openings
 Vena caval opening in central tendon
 Oesphagel in right crus of diaphragm
 Aortic opening behind median arcuate ligament

16. Diagram of inlet thorax

17.  Small openings
 Superior epigastric artery
 Musculophernic artery
 Lower 5 intercostal vessels and nerves
 Sub costal vessels and nerves

18. Structure passing through
diaphragm

19. BONES AND JOINTS OF THORAX
 INTRODUCTION:
The thorax is an osseocartilaginous cavity or cage for
various viscera, providing them due support and
protection.
This cage is not static, but dynamic, as it moves
at its various joints, increasing or decreasing the various
diameters of the cavity for an extremely important
process of respiration, which is life for all of us.

20. BONES OF THORAX
RIBS OR COSTAE
12 Pairs of ribs on each side forming the greater part of
the thoracic skeleton.
The number may be increased by development of a
cervical or a lumbar rib; or the number may be
reduced to L1 by the absence of the twelfth rib.
The gap between ribs are called intercostal spaces
Ribs are arranged oblique.

21. Ribs
Typical Ribs 2-7
Head
Neck
Tubercle
Angle
Shaft
Subcostal groove
Atypical Ribs 1,8 -10
•Rib 1- short, flat and
supports Subclavian
vessels
•Ribs 1,10-12 - articulate
with only 1vertebra
• Ribs 11and 12–
“floating ribs” – do not
articulate withTransverse
processes of Vertebrae or
Sternum

22. True ribs: 1– 7 pairs of ribs
are attached anteriorly to
the sternum by their costal
cartilages.
False ribs: 8th, 9th and 10th
pairs of ribs are attached
anteriorly to each other and to
the 7th rib by means of their
costal cartilages and small
synovial joints.
Floating ribs :The 11thand
12th pairs have no anterior
attachment. They are
embedded in theabdominal
muscles.

23. Typical Ribs (2 -7)
• Long, twisted, flat bone
• The anterior end of each rib is attached to the corresponding costal
cartilage
• Arib has a head, neck, tubercle, shaft, and angle
• Head – located posteriorly - has 2 facets for articulation – one for the
numerically corresponding vertebral body and the other for the vertebral
body immediately aboveit.
• Neck is a constricted portion - between the head and the tubercle.
• The Tubercle is a prominence on outer surface of the rib - at the
junction of the neck with the shaft. It has a facet for articulation with the
transverse process of the numerically corresponding vertebra.
• The Shaft is thin, flat and twisted on its long axis.
• It has a rounded, smooth superior border and a sharp, thin inferior
border which has costal groove (it accommodates the intercostal
vessels and nerve (VAN ) The angle is where the shaft of the rib bends
sharply forward.

28. Atypical Rib (1st Rib)
• The first rib has a close relationship to the lower nerves of the
Brachial plexus, Subclavian artery and vein
• This rib is small and flattened from above downward
• Scalenus anterior muscle is attached to its upper surface and inner
border
• Anterior to the attachment of Scalenus anterior, the Subclavian
vein crosses therib
• Posterior to the attachment of Scalenus anterior, the Subclavian
artery and the lower trunk of the Brachial plexus cross the rib
and lie in contact with the bone

29. Clinical Anatomy
• Fracture of 1st rib maycause:
• Injury to lower trunk of Brachial plexus: Klumpke’s
paralysis
• Injury to Subclavianvessels:
Hemorrhage/Ischemia
• Thoracic outlet syndrome: Compression of
Subclavian vessels/Brachial plexus between 1stRib
and Clavicle – Klumpke’s paralysis and ischemia.

31. Sternum/Breast bone
Flat bone, with 3parts:
1. Manubrium sterni
2. Body/Gladiolus
3. Xiphoid process

32. PARTS OF STERNUM:
1. Manubrium sterni
Jugular/suprasternal notch
Articulates with Clavicles
and Ribs 1and 2
Lies opposite to T3 and T4
vertebrae
Manubriosternal joint
inferiorly – called Sternal
Angle/Angle of Louis –
opposite articulationwith
2nd rib – at the level of
intervertbral disc between
T4 and T5vertebrae
(imp. for counting the ribs)

33. PARTS OF STERNUM:
2. Body/Gladiolus
Articulates with Ribs2-7
Xiphisternal joint inferiorly-
opposite toT9 vertebra
3. Xiphoid process
Cartilaginous - calcifies
through time
Allows attachment of
muscles
Tip of xiphoid – at level of
T10

35. Clinical Anatomy
1. Bone marrow biopsy (to take sample of bone
marrow)
1. Median sternotomy (Sternum is split in half,
longitudinally to gain access to thoracic organs for
surgery)

36. Sternocostal joints

37. JOINTS OF THORAX
 MANUBRIOSTERNAL JOINT:
Manubriosternal joint is a secondary cartilaginous joint. It
permits slight movements of the body of the sternumon on
the manubrium during respiration.
 COSTOVERTEBRAL JOINT:
The head of a typical rib articulates with its own
vertebra, and also with the body of the next higher vertebra,
to form two plane synovial joints separated by an intra-
articular ligament.
 COSTOTRANSVERSE JOINTS:
The tubercle of a typical rib articulates with the transverse
process of the corresponding vertebra to form a synovial
joint.

38.  COSTOCHONDRAL JOINTS
 Each rib is continuous anteriorly with its cartilage, to
form a primary cartilaginous joint. No movements are
permitted at these joints.
 CHONDROSTERNAL JOINTS
The first chondrosternal joint is a primary cartilaginous joint,
it does not permit any movement. This helps in the
stability of the shoulder girdle and of the upper limb.
 INTERVERTEBRAL JOINTS
 Adjoining vertebrae are connected to each other at three
joints. There is a median joint between the vertebral
bodies, and two joints-right and left-between the articular
processes.The joints between the articular processes are
plane synovial joints.

39. The vertebral column, also called the
spine, spinal column or backbone.
Composed of a series of bones called
vertebrae (singular is vertebra).
About 71 cm (28in): adult male.
About 61 cm (24in): adult female.
3
9

40. Total number of vertebrae during early
development is 33.
As a child grows, several vertebrae in the
sacral and coccygeal regions fuse.
Adults have 26 vertebrae. *Sacrum and
coccyx bones become fused.

41. 7 cervical vertebrae (C1 - C7 )
12 thoracic vertebrae (T1 –T12)
5 lumbar vertebrae (L1 – L5)
1 sacrum ( 5 fused )
1 coccyx ( 4 fused )
*The sacrum and coccyx do not have
number.

42. The cervical, thoracic and lumbar vertebrae
movable
Sacrum and coccyx immovable
Between adjacent vertebrae from the
second cervical vertebra to the sacrum are
intervertebral disc (inter = between).
42

43. 43

44. General Structure of Vertebrae
44
1. Cervicalvertebrae (C1-C7)
•
•
•
•
Formedframeworkof neckregion
Support skull
Smallin size
Presenseforamenineachtransverse process
2. Thoracicvertebrae (T1-T12)
•
•
Formedposteriorpartof thoraciccage
Articulateswithassociated ribs

45. 3. LumbarVertebrae (L1-L5)
45
•
•
Formedskeletalsupportforposteriorabdominalwall
Characterizedbylargeinsize
4. Sacrum Vertebrae
•
•
•
•
•
Fusionof 5sacralbones
Immovable(synostosis)
ArticulateswithL5atlumbosacraljoint
Articulateslaterallywithpelvicboneatsacroiliacjoint.
Formedposteriorwallof lowerabdominalandpelvic cavity
5. Coccyx
•
•
•
Fusionof 4coccyxbones
Immovable(synostosis)
Formedpartof pelviccavity

46. 1. Supports the head.
2. Help maintain balance in the upright
position.
3. Enclose and protect the spinal cord.
4. Permits movement (move forward,
backward, sideways, and rotate).
5. Absorbs shocks during walking.
6. Serve as a point of attachment for the ribs,
pelvic girdle and muscles of the back and
upper limbs.
46

47. In the fetus, there is a single concave
curve.
At 3 months after birth when infant lifts head
as it begins to crawl the cervical curve
develops.
When child sits up, stands and walks the
lumbar curve develops.
47

48. In adult, it shows four slight bends called
normal curve:
Cervical and lumbar curve are convex
(bulging out)
Thoracic and sacral curve are concave
(cupping in)

49. 49

50. 50

51. The thoracic and sacral curves are called
primary curves because they form first
during fetal development.
The cervical and lumbar curves are called
secondary curves because they form later,
several months after birth.
All curve fully developed by age 10.
However, secondary curves may be
progressively lost in old age.
51

52. Newborn Spinal Curvature :
52
C-shaped curve
Known as Primary Curve
Single curve
Adult Spinal Curvature:
S-shaped vertebral column
Four curve (cervical, thoracic, lumbar amd
sacral curve)
Secondary curvatures develop after birth
Differences newborn and adult spinal curvature

53. 53

54. Consist of four slight
bends (cervical,
thoracic, lumbar,
sacral)
Cervical and lumbar
curve are convex
(bulging out).
The thoracic and
sacral curves are
concave (cupping in).
54

55. Increases its strength
Help maintain balance in the upright
position
Absorb shocks during walking
Help protect the vertebrae from fracture
55

56. ABNORMAL SPINAL
CURVATURE

57. ABNORMAL SPINAL
CURVATURE
22

58. Typical vertebrae consists of:
◦ A body
◦ A vertebral arch (pedicles and lamina)
◦ Seven processes: two transverse
processes, one spinous process, four
articular processes
58

59. Largest part of vertebra,
thick.
Disc-shaped anterior
portion
Weight bearing portion –
size increases inferiorly
Its inferior and superior
surfaces are roughened and
give attachment to the
intervertebral disc.
Anterior and lateral
surfaces contain nutrient
foramina – pathway for
blood vessels.
59

60. Extend backwards from the body of the
vertebra.
Consists of a pair of pedicles and a pair of
laminae.
The pedicle project backward from the body to
unite with the laminae.
60

61. 7 processes arise from
the vertebral arch:
TWO TRANSVERSE PROCESS
ONE SPINOUS PROCESS
FOUR ARTICULAR
29

62. TRANSVERSE PROCESS:
Extends posterolaterally
for the junction between
pedicle and laminae on
each side (left and right)
ONE SPINOUS PROCESS:
A single spinous process
projects posteriorly from
the junction of the laminae.
These 3 processes serve
as points of attachment for
muscles.

63. ARTICULAR PROCESSES (Zygapophyses):
At the junction between pedicles and lamina meet, also
projecting superior and inferior articular process.
At the end of these processes – concave surface (facet)
IAP of vertebrae above articulates with SAP of vertebrae
below – zygapophysial joints (Facet Joints).
63

64. Between the bodies of the
adjacent vertebrae C2 to
the sacrum.
Each disc forms a
cartilaginous joint to allow
slight movement of the
vertebrae, and acts as a
ligament to hold the
vertebrae together.
64
INTERVERTEBRAL DISCS

65. Each vertebral discs consist of:
an outer fibrous ring consisting of
fibrocartilage called called annulus
fibrosus (annalus = ringlike).
Inner soft, pulpy, highly elastic substance
called the nucleus pulposus (pulposus =
pulplike), which is acts as a shock
absorber, absorbing the impact of the
body's daily activities and keeping the two
vertebrae separated
65

66. Nucleus pulposus hardens and
less elastic with age.
Narrowing of discs and
compression of the vertebrae
results in a decrease in the
height with age.
A tear can occur within the
annulus fibrosus (ring) and cause
the nucleus pulposus may track
into the vertebral canal or
intervertebral foramen to impinge
on neural structures – herniation
IV discs. (prolapsed/slipped disc)
66

67. 1. Binds the vertebrae and
forms a strong joint
2. Permits various
movements of the
vertebral column
3. Absorbs vertical shock
and avoid friction during
intervertebral joints
movements.
67

68. Vertebral foramen
contains : spinal cord
and its roots, spinal
meninges, ASA and
PSA, Venous Plexus, fat
The vertebral foramina
of all vertebrae form the
vertebral (spinal) canal.

69. 69
C1-C7 (formedframeworkof theneck)
C1, C2 andC7 – atypical(looks weird!!!)
C3-C6 – havesimilarities– typical
◦ Smallerbodies, short
◦ Largervertebralarch– hencelargervertebralforamen(cervical
enlargement)
◦ Transverseprocessconsisttransverseforamina@ foramen
transversarium(vertebral artery)
◦ Spinousprocessshortandbifid
Cervical Vertebrae

70. Typicalthoracic vertebrae
◦ Fairlylargesizeof body
◦ Longspinousprocessand
pointedandangled
downward
◦ Vertebralforamengenerally
circular
◦ Transverseprocess
projectingposterolaterally
.
◦ Have3 pairs of facets–
attachmentfortheribs(2
pairsof demifacetsatthe
bodyand1pairof facetat
thetransverseprocess.
Thoracic Vertebrae (T1-T12)
70

71. 71
T1hasasuperiorfacetandinferiordemifacetsforheadof ribs.
T2-T8havesuperiorandinferiordemifacetsforheadof ribs.
T9hasasuperiordemifacets
T10-T12havesuperior facet.
Movementsof thethoracicvertebraearelimitedbythinintervetebraldisc
andbyattachmentof theribstothesternum(sternocostaljnt).

72. Movements of vertebral column
 Movements between adjacent vertebrae occur
simultaneously at all the joints connecting them.
 Movement between any two vertebrae is slight.
 However, when the movements between several
vertebrae are added together the total range of
movement becomes considerable. The movements are
those of flexion, extension, lateral flexion and a certain
amount of rotation.

73. Respiration Movements
 The lungs expand during inspiration and retract
during expiration. These movements are governed by
the following two factors.
Alterations in the capacity of the thorax are brought
about by movements of the thoracic wall. Increase
in volume of the thoracic cavity creates a negative
intrathoracic pressure which sucks air into the lungs.
Movements of the thoracic wall occur chiefly at the
costovertebral and manubriosternal joints.

74. Elastic recoil of the pulmonary alveoli and of the
Thoraic wall expels air from the lungs during expiration.

75. Principals of Movement
1.Each rib may be regarded as a lever, the fulcrum of
which lies just lateral to the tubercle. Because of the
disproportion in the length of the two arms of the
lever, the slight movements at the vertebral end of
the rib are greatly magnified at the anterior end.
2. The anterior end of the rib is lower than the posterior
end. Therefore, during elevation of the rib, the
anterior end also moves forwards. This occurs mostly
in the vertebrosternal ribs. In this way, the
anteroposterior diameter of the thorax is increased.
Along with the up and down movements of the
second to sixth ribs, the body of the sternum also
moves up and down called pump-handle moaements.
This results in formation of sternal angle.

77. 3. The middle of the shaft of the rib lies at a lower level
than the plane passing through the two ends.
Therefore, during elevation of the rib, the shaft also
moves outwards. This causes increase in the
transverse diameter of the thorax.
4. The thorax resembles a cone, tapering upwards. As
a result each rib is longer than the next higher rib.
On elevation the larger lower rib comes to occupy
the position of the smaller upper rib. This also
increases the transverse diameter of the thorax

78. 5. Vertical diameter is increased by the "piston
movements" of the thoracoabdominal diaphragm.