Anatomy of Thoracic Cage, Thoracic Wall

1. Dr Asma Lashari
University Of Health Sciences
Lahore Pakistan

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

6. 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)

7. 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

9. ClinicalAnatomy
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)

11. 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

12. Typical ribs: 1– 7 pairs of
ribs are attached anteriorly to
the sternum by their costal
cartilages.
Atypical 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.

13. TypicalRibs(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.

17. AtypicalRib(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

18. ClinicalAnatomy
• 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.

21. Articulations of Rib Cage:
The articulations that
join the bones of the
rib cage are:
 Manubriosternal (MS),
 Xiphisternal (XS),
 Costovertebral (CV),
 Costotransverse (CT),
 Costochondral (CC),
 Chondrosternal (CS),
 Interchondral.

22. JOINTSOFSTERNUM
1.MANUBRIOSTERNAL JOINT:
cartilaginous joint, symphysis
between Manubrium and body of Sternum
2. XIPHISTERNALJOINT
cartilaginous joint
between Xiphoid process and body of Sternum
The Xiphoid process usually fuses with the body of the
Sternum during middleage

23. JOINTSOFRIBS
1.COSTOVERTEBRAL JOINTS:
2 joints between heads of the Ribs and bodies of
Vertebrae (corresponding and upper)- Synovial joints
Atypical CV Joint: 1st, 10th, 11thand 12th rib has 1
synovial joint with the corresponding vertebra,
Typical CV Joint: 2nd to 9th ribs have 2 joints each;
one for the corresponding vertebra and the other
for the vertebra above it.
Rotation and gliding movements.

25. Intra articular ligament
connects head of Rib to the
intervertebral disc
Radiate ligament has three
bands:
superior band, attached to
the superior vertebra
intermediate band, attached
to the intervertebral disk;
and the
inferior band, attached to the
inferior vertebra.
Ligaments of Costovertebral Joints:

27. 1joint between costal
tubercle of Ribs and
costal facet on
transverse process of
Vertebra (corresponding)
- Synovial joint (1st- 10th
Rib)
Ribs 11 and 12 do not
articulate with their
respective transverse
processes of T11 or T12.
At the CT joints of T7
through T10,both articular
surfaces are flat and gliding
motions predominate.
2. COSTOTRANSVERSE JOINTS:

28. Three major ligaments support
the CTjoint capsule .
lateral costotransverse
ligament, between the lateral
portion of the costal tubercle
and the tip of the corresponding
transverse process.
costotransverse ligament,
between the neck of the rib
posteriorly and the transverse
process at the same level.
superior costotransverse
ligament, runs from the crest
of the neck of the rib to the
inferior border of the
transverse process.
Ligaments Of Costotransverse Joints:

29. 3. COSTOCHONDRALJOINTS:
Joints of the Ribs with costal cartilages
Cartilaginous joints
4. COSTOSTERNALJOINTS:
Joints between Sternum and costal cartilages
1st: Cartilaginous joint, with lateral facet of manubrium
2nd – 10th : Synovial joints=
2nd-7th costal cartilages with Sternum
8th-10th costal cartilages with eachother
(11thand 12thcostal cartilages are embedded inmuscles)

30. Anterior and posterior
radiate costosternal
ligaments.
The costosternal ligament is
an intra- articular ligament,
that divides the two
demifacets of the 2nd CSjoint.
The CS joints may ossify with
aging.
The costoxiphoid ligament
connects the ant. and post.
surfaces of the 7th costal
cartilage to the front and back
of the xiphoid process.
Ligaments Of Costosternal Joints

31.  The 7th – 10th costal cartilages
articulate with cartilage above them.
 For 8th -10th ribs, articulation
is indirectly with sternum .
 Interchondral joints are synovial
joints and are supported by a capsule
and interchondral ligaments.
 The interchondral articulations, tend
to become fibrous and fuse with age.
5. INTERCHONDRALJOINTS:

32. MOVEMENTS
Cartilaginous joints are immobile (thus 1st rib and
all costochondral joints do not move during
respiration)
Synovial joints are slightly mobile (due to
movements in both the joints between head,
tubercle and vertebrae, necks of Ribs rotate along
their axis, helping in raising and lowering of ribs
during respiration)

33.  During inspiration, the ribs elevate.
 In upper ribs, most of movement
occurs at anterior aspect of the rib,
nearly frontal axis at the vertebrae.
 The movement of ribs pushes the
sternum ventrally and superiorly.
 Less movement occurs at manubrium
becoz first rib is short this causes
movement at the MS joint.
 The motion of upper ribs and sternum
has greatest effect by increasing
anteroposterior (A-P) diameter of thorax.
 This combined rib and sternal motion
has been termed as “pumphandle”
motion.

34.  Elevation of the lower ribs occurs
nearly at sagittal axis.
 Lower ribs have more angled shape and an
indirect attachment anteriorly to sternum.
 These factors allow the lower ribs more
motion at the lateral aspect of the rib cage.
 Elevation of the lower ribs has greater
effect to increase the transverse diameter
of the lower thorax.
 This motion has been termed the
“bucket- handle” motion of the
thorax.
 The intermediate ribs perform both
types of motion.
 The 11th and 12th ribs do not
participate in closed-chain motion of
the thorax.

35. CervicalRib(AccessoryRib)
Occurs in 0.5%population
There is an extra pair of ribs just above the 1st rib
They arise from the transverse process of C7 vertebrae
Anteriorly, they may be attached to 1st Rib or may be
free
Clinical Anatomy: Cervical Rib may compress Brachial
plexus/Subclavian artery; causing Klumpke’s
paralysis/Ischemia

37. Thoracic Vertebra
 There are 12 thoracic vertebra.
 From 2 to 9 they are called Typical.
 1st, 10th,11th and 12th are Atypical.

38. Character of typical thoracic
vertebrae:
 Body: Heart shape & carries 2
demi-facet at its side.
 Transverse process: has a
facet for rib tubercle of the
same number.
 Spine: Long, pointed &
directed downward and
backward.
 Vertebral foramen: Small &
circular.

39. T1:
 Has a complete facet.
 One very small inferior
demifacet.
 Spine nearly horizontal
 Has costal facet in
transverse process for the
tubercle of first rib.
 It has a small body, looks
like a cervical vertebra.
Atypical (Non typical )

40. T10
 One complete facet tangential with
the upper border
 Small costal facet on transverse
process.
T11
 One complete circular facet away
from upper border.
 No costal facet
T12
 Broad body & short, oblong spine.
 One complete facet midway between
upper & lower borders.
 No costal facet

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