Bones and joints of thorax

1. Thorax
The hard part

2. BONES AND JOINTS OF THE THORACIC WALL

3. STERNUM
the anterior median part of the thoracic cage.

4. PARTS OF A
STERNUM
It consist of three parts
1.Manubrium sterni
2.Body
3.Xiphoid process

5. Anatomical position
● Quadrilateral manubrium is directed
upwards & triangular xiphoid process is
directed downwards.
● Anterior surface of the manubrium is
convex from side to side and concave from
above downwards.
● Anterior surface of the body is flat and
marked by three transverse ridge and the
posterior surface of the body is smooth&
slightly concave.

6. Features
● It is morphologically a flat bone. It's ossification is intra
cartilaginous ossification.
● Manubrium has two surface
& Four borders.
● The superior border ia thik, rounded and marked by
jugular notch or suprasternal notch on middle &
clavicular notch on each side.
● Manubrium makes a slight angle with the body of
sternum called sternal angle of Luis.
● The lateral border of the sternum contain 7 pair of costal
facet.

7. Attachment
Manubrium
Anterior surface- sternocleidomastoid muscle & pectoralis major muscle .
Posterior surface - sternohyoid (upper) & Sternothyroid (lower)
Body of the sternum
Anterior surface- pectoralis major muscle (on each side)
Posterior surface - sternocostalis muscle (Lower lateral part)
Lateral border - internal intercostal muscle & external intercostal membrane
Xiphoid process
Anterior surface - rectus abdominalis muscle
Posterior surface - The diaphragm

8. Relations
Manubrium
Posterior surface: Arch of aorta (Lower
half), branches of arch of aorta (upper
half)& branches are brachiocephalic trunk,
left common carotid and left subclavian
artery
Body of the sternum
Right side: Right lung & right pleura
Left side: left lung & left pleura (upper
half)

9. Joints
1.Sternoclavicular joint is a saddle
synovial joint.
2.Manubrio-sternal joint is a secondary
cartilaginous joint.
3. Xiphisternal joint is primary
cartilaginous joint
4.1st chondrosternal joint is a primary
cartilaginous joint.
5.2nd-7th chondrosternal joint is synovial
joint.

10. Clinical importances of sternum
● Bone marrow collection: from Sternum
cause it contains red bone marrow
throughout the life.It is done in upper part
of manubrium to prevent injury to arch of
aorta which lies behind its lower half.

11. Ribs
Lateral boundary of thoracic cage

12. Classifications
According to their features
1.Typical ribs-3rd to 9th
2.Atypical ribs

13. Typical ribs

14. Ribs of similar features.

15. Identifications
1.Costal groove at the lower border
of internal surface.
2.Twisted,angulated and curved
shaft

16. Anatomical position
❄️Posterior end is higher and medial than
the anterior end.
❄️The anterior end bears a concave
depression to receive its own costal
cartilage.
❄️The shaft is thin,flat and curved with
convexity directed outward.
❄️The inner surface of the shaft is
marked by costal groove near the lower
border

17. Parts
1.Two ends-
Anterior end bears a concave depression that forms the
costo- chondral joint.Posterior end bears - a)Head bears
two facets separated by crest b)Neck possesses two
surfaces-anterior and posterior.Two borders-upper and
lower.c)Tubercle bears two parts-Medial articular part that
forms costo- transverse joint and Lateral non-articular part.
2.Shaft-
It is curved with convexity directed outward and twisted.It
possesses two surfaces-external surface is convex and
smooth and internal surface is smooth .Two borders-
rounded upper and sharp lower borders.

18. Attachments
1.Radiate ligament,intra-articular ligament at the head.
2. Inferior costotransverse ligament at the rough posterior part, Superior
costotransverse ligament at the crest of the neck. The anterior surface is covered by
costal pleura.
3.The Lateral costotransverse ligament is attached to the lateral non-articular part of
Tubercle.
4.The thoracolumbar fascia, lateral fibres of Sacrospinalis muscle,lere attached to the
posterior angle. The anterior angle separates the origin of External oblique and
serratus anterior in 5th-8th ribs and External oblique from Latissimus dorsi in 9th-
10th rib.

19. Attachment
5. The Internal intercostal muscle arises
from the floor of costal groove and the
Innermost intercostal muscle arises from
the middle two-fourths of the ridge above
the groove.
6. The External intercostal muscle is
atteched on the outer lip and Internal &
Innermost intercostal muscle are
attached on the inner lip of the upper
border of the shaft.

20. Relations
Internal surface lodges
intercostal vein,artery
and nerve from above
downwards.

21. Joints
1.Costo-vertebral joint
2.Costo-transverse joint
3.Costo-chondral joint

22. Ossifications
1.One primary centre-for shaft.
2.Three secondary centres-for
head and two tubercle.

23. Atypical
ribs
1st,2nd,10th,
11th and 12th ribs

24. The first rib

25. Identifications
1.Single circular facet
2.No costal grooves
3.Scalene tubercle in inner border
4.Shortest,broadest,flat,curved
5.No twist,no angle

26. Anatomical position
1.Anterior end is larger,thicker and
pitted
2.Posterior end is small and rounded.
3.Both ends touch the surface.
4.Posterior end is higher than the
anterior end.

27. Parts
1.Two ends -
Anterior end is largest and thickest which articulates with 1st costal
cartilage.
Posterior end bears a)Head bears single circular facete. b)Neck c)Tubercle
is prominent and thik.It faces upwards and backwards.
2.Shaft
It possesse two surfaces -Upper surface is marked by two shallow grooves
that ends in scalene tubercle.Lower surface is smooth and no costal
grooves.Two borders-convex outer and concave inner border.

28. Attachments
1.Capsular ligament and radiate ligament on head
2.Inferior costo-transverse ligament and superior costo-transverse ligament on neck.
3.Lateral costo-transverse ligament on tubercles.
4.Scalenus anterior,subclavius,scalenus medius, costo-clavicular ligament on upper
surface.External and Internal intercostal muscle on lower surface.1st digitation of
serratus anterior on outer border. Supra-pleural membrane and scalenus anterior on
inner border.

29. Relations
1.Sympathetic trunk,1st posterior intercoastal
vein,superior intercoastal artery,1st thoracic
nerve,lower trunk of branchial plexus lies
anteriorly on neck from medial to lateral.
2.Subclavian vein,artery and lower trunk of
branchial plexus on upper surface.
3.1st intercoastal vein and artery on outer border.

30. The second rib

31. Identifications
1.More curved
2.Twice longer than 1st rib
3.Head is small and bears two facets .
4.Non-articular part of tubercle is small
5.No twist,slight angle,slight costal groove on
posterior internal surface.
6.Angle is close to the tubercle.

32. Anatomical position
1.Both ends touch surface
2.Posterior end is higher and medial
than the anterior end.
3.Tubercle is in middle of the external
surface.

33. Parts
1.Two ends-
Anterior end lies forward
and downward.Posterior
End lies backward,upward
and medially.
2.Shaft
Convex external surface faces upwards and outwards.Concave Internal
surface faces downwards and inwards.

34. Attachments
Scalenus posterior and serratus
posterior superior on angle.
Half of the 1st and whole of the
2nd digitation of serratus
anterior.
Others are as typical ribs.

35. ◾10th Rib

36. Anatomical Points
❄️The posterior end is higher and nearer to the
medial plane.
❄️ Posterior end comprises head,neck,tubercle
and the anterior end bears a concave depression
to receive its own cartilage.
❄️The inner surface is smooth and marked by a
costal groove close to its lower border.

37. Joints
❄️Anterior end articulate with costal cartilage → costochondral junction.
❄️Head articulates with body of vertebrae → costovertebral joint.

38. Attachment and Relation
Attachment
❄️ Upper lip→innermost intercostal
❄️Lower lip→external intercostal
Relation of costal groove
❄️ Intercostal vein
❄️Intercostal artery
❄️Intercostal nerve

39. 11th and 12th Rib
Termed as Floating Rib

40. Floating Rib
They are floating ribs becuase anterior ends are
free. They have no communication with the
sternum

41. Anatomical Position
❄️The posterior end is higher and nearer to the medial plane.
❄️Posterior end comprises only head. There is no neck and tubercle.
❄️The inner surface is marked by shallow costal groove only on its posterior aspect.
❄️There is an angle on the shaft.
❄️Anterior end is pointed.

42. Attachment of 12th Rib

43. Attachment
1. External surface
→ From medial to lateral
a. Lavaetor Costae
b. Longissimus Thoracis
c. Illio-costalis
→Laterally
a.Serratus posterior anterior
b.Lattimus dorsi
c.External oblique

44. Attachment
2. Internal surface
a.Upper part→ Diaphragm
b. medial part→ Quadratus lumborum
3. Upper border→ External and internal
intercostal muscles
4. Lower border→ Lumbocostal ligament

45. Thoracic vertebrae
Posterior boundary of thoracic cage

46. Thoracic vertebrae

47. Classifications
According to features
1.Typical vertebra
2.Atypical vertebra

48. Typical thoracic vertebra
Vertebra are the interlocking bones
that form the spinal column. Among
the 33 individual, 12 are thoracic
vertebra.
Out of 12 thoracic vertebta, the second
to eighth are marked as the typical
thoracic vertebra because they carry
some common carecteristic features
Vertebra are the interlocking bones
that form the spinal column. Among
the 33 individual, 12 are thoracic
vertebra.
Out of 12 thoracic vertebta, the
second to eighth are marked as the
typical thoracic vertebra because
they carry some common
carecteristic features
Vertebra are the interlocking bones
that form the spinal column. Among
the 33 individual, 12 are thoracic
vertebra.
Out of 12 thoracic vertebta, the
second to eighth are marked as the
typical thoracic vertebra because
they carry some common
carecteristic features

49. Identification
● The thoracic vertebra are identified by two
demifacets on the both sides of the body.
● the typical thoracic vertebra are identified by
costal facets on the anterior surface of
transverse process

50. Anatomical
position
● The body lies anteriorly
● The arch lies posteriorly
● The large transverse process
is directed backward and
laterally from the junction of
pedicle and lamina.
● The long spinous process is
directed backwards and
downwards
.

51. Features
● The body is heart shapef.That is the anteroposterior
diameter and the transverse diameter are almost
equal. On each sidel,it bears two demi facets.
● The vertebral foramen is circular and small. The
pedicles are short.The superior articular process is not
well marked but the inferior articular process is
conspicuous. The laminae are short, thick and board
and overlap from above downwards.
● And the large transverse process arises from the
junction of pedical and lamina and directed backwards
and somewhat laterally. In the anterior surface, it has
a concave costal facet
● The spinous process is long and directed backwards
and downwards

52. Attachment
● The anterior part of the body is attached to the
anterior longitudinal ligament and the posterior
part of the body is attached to the posterior
longitudinal ligament.
● The laminae of adjacent vertebra are connected
with a series of fibro-elastic membrane which is
named ligamenta flava.
● The transverse process gives attachment to
● . The lateral costotransverse ligament at the
tip.
● . The intertransverse muscles and ligaments
along the upper and lower border.
● . The superior costotransverse ligament along
the lower border
● . The inferior costotransverse ligament along
the anterior surface
● . The levator costae and deep muscle of the
back to the posterior surface

53. The spinous process gives attachment to the supraspinous and
interspinous ligaments
They also give attachment to several muscles including :
Trapezius
Rhomboids major and minor
Latissimus dorsi
serratus posterior superior
serratus posterior inferior
multifidus
sacrospinalis
semispinalis capitis
the content of vertebral foramen in spinal cord with its meninges

54. Joints
● Facet joint or zygacophyseal joint : the joint between
superior articular process and inferior articular process
of adjoining vertebrae.It is a plane type of Synovial
Joint.
● Intervertebral joint :the joint between the body of two
corresponding vertebra. it is a secondary cartilaginous
joint.
● Costovertebral joint: the joint between superior costal
demifacet of a vertebra and head of corresponding rib.
It’s a plane type of synovial joint.
● Costotransverse joint: The joint between costal facet of
a vertebra and tubercle of corresponding rib.It is also a
plane type of synovial joint

55. Atypical thoracic vertebrae

56. Atypical
Thoracic
Vertebra

57. First Thoracic vertebra
1.Body is cervical in form as transverse diameter
is twice than anterior-posterior diameter.
2.Upper costal facetes are circular and lower
costal facetes are semicircular
3.Spine is thik amd lies horizontally
4.No foramen transversarium

58. 9th Thoracic vertebra
1.Large semicircular facate above
2.Small semilunar facate below or may ne
absent
10th Thoracic vertebra
1.Large facetes above and lower facetes are
absent.Facetes of transverse processmay be absent
2.Upper facetes enroach upon the pedicle

59. 11th Thoracoc vertebra
1.Complete circular facet which extends back on pedicle
2.No facet on transverse process
12t Thoracic vertebra
1. circular facet which enroaches on pedicle
2.Body is large and resembles tjat of lumbar vertebra
3.No facet on transverse process
4.Inferior articular facet is convex and twisted laterally.
5..Transverse process has three tubercles-(a).Superior, which corresponds to mamillary process (b)
Lateral, which corresponds to transverse process and (c)Inferior, which corresponds to accessory process.

60. Thank you slide
Student’s most favourite slide