Thoracic cage Thoracic. inlet.pdf

Thoracic cage

1. By
DARE SAMUEL SUNDAY
Department of Human Anatomy, KABSOM

2. 
ThechestisRegionbetweentheneckandabdomen.

Flattenedinfront&behindbutroundedatthesides

Frameworkiscalledthoraciccage
2

3. 
Coveredontheoutsidebyskinandmusclesattachingthe
shouldergirdletothetrunk.

Linedwithparietalpleuralontheinside.
Walls

Anteriorly:Sternum&costalcartilages

Posteriorly:Thoracicpartofvertebralcolumn

Laterally:Ribs&intercostalspaces

Superiorly:Suprapleuralmembrane

Inferiorly:Diaphragm
3

4. 
A flat bone in the midline of the anterior chest wall

Divided into: manubrium sterni, body & xiphoid process

Relatively shorter and thinner in the female

Sternal angle (Angle of Louis): formed by articulation of the
manubrium with the body of the sternum

Joints:
◦Manubriosternal –level of disc btw T4 & T5
◦Xiphisternal –opposite the body of T9
◦Manubrium articulates with clavicle and 1
st
rib
◦Body of sternum articulates with 2
nd
to 7
th
costal cartilages.
4

5. 
Sternum and Marrow Biopsy
Since the sternum possesses red hematopoietic marrow throughout
life, it is a common site for marrow biopsy.

Under a local anesthetic, a wide-bore needle is introduced into the
marrow cavity through the anterior surface of the bone.

The sternum may also be split at operation to allow the surgeon to
gain easy access to the heart, great vessels, and thymus.
5

6. Consistof12pairsofbonesthatformthemainpartofthe
thoraciccage
Structure:

Typicalrib:longtwistedflatboneandhashead,neck,tubercule
angle&body(e.g3
rd
to9
th
ribs)

Atypicalrib:aredissimilar(1
st
,2
nd
,10
th
,11
th
&12
th
ribs)
Classification:

Trueribs:areribsattachedtotheircostalcartilages

Falseribs:ribs8
th
,9
th
,10
th
attachedtocostalcartilageofthe7
th
rib.

Floatingribs:11
th
&12
th
,hasnoattachmentanteriorly.
6

7. First Rib

Is the broadest and shortest of the true ribs.

Has a single articular facet on its head, which articulates with
the first thoracic vertebra.

Has a scalene tubercle for the insertion of the anterior scalene
muscle and two grooves for the subclavian artery and vein.
Second Rib

Has two articular facets on its head, which articulate with the
bodies of the first and second thoracic vertebrae.

Is about twice as long as the first rib.
7

8. Tenth Rib

Has a single articular facet on its head, which articulates with
the 10th thoracic vertebra.
Eleventh and Twelfth Ribs

Have a single articular facet on their heads.

Have no neck or tubercle.
8

9. 9

10. 
Joints of the Sternum

Joints of the ribs
◦Head
◦Tubercules
◦Costal cartilages
◦Sternum
10

11. SternoclavicularJoint

Saddle-type synovial joint with two separate synovial cavities

Provides the only bony attachment between the appendicular
and axial skeletons.
Sternocostal(Sternochondral) Joints

Articulates the sternum with the first seven cartilages.

Articulation of manubrium with first costal cartilage is
synchondrosis(cartilaginous)

Second to seventh costal cartilages form synovial plane joints
with the sternum.
11

12. CostochondralJoints

Articulation of ribs with their respective costal cartilages

Are synchondroses.
ManubriosternalJoint

Between manubrium and body of the sternum.

Is symphysis (secondary cartilaginous joint)
XiphisternalJoint

Articulation between xiphoid process and body of the sternum
is synchondrosis
12

13. CostovertebralJoints

Synovial plane joints of heads of ribs with corresponding and
supraadjacentvertebral bodies.
CostotransverseJoint

Synovial plane joint of tubercle of rib with transverse process
of corresponding vertebra.
InterchondralJoints

Synovial plane joints between 6th and 10th costal cartilages of
ribs.
13

14. Boundaries

Anteriorly:Superiorborder
ofmanubriumsterni

Posteriorly:Firstthoracic
verterbra

Laterally:Medialborderof
firstribsandtheircostal
cartilages
14

15. 
TheThoracicOutletSyndrome
Thebrachialplexusofnerves(C5,6,7,and8andT1)andthe
subclavianarteryandveinarecloselyrelatedtotheupper
surfaceofthefirstribandtheclavicleastheyentertheupper
limb.

Itisherethatthenervesorbloodvesselsmaybecompressed
betweenthebones.Mostofthesymptomsarecausedby
pressureonthelowertrunkoftheplexusproducingpaindown
themedialsideoftheforearmandhandandwastingofthe
smallmusclesofthehand.Pressureonthebloodvesselsmay
compromisethecirculationoftheupperlimb.
15

16. MuscleOrigin InsertionNerveAction
External
intercostals
Lower border of ribsUpper border of
rib below
IntercostalElevate ribs in
inspiration
Internal
intercostals
Lower border of ribsUpper border of
rib below
IntercostalDepress ribs (costal
part);
elevate ribs
(interchondral
part)
Innermost
intercostals
Lower border of ribsUpper border of
rib below
IntercostalElevate ribs
Transversus
thoracis
Posterior surface of
lower sternum and
xiphoid
Inner surface of
costal
cartilages 2–6
IntercostalDepresses ribs
SubcostalisInner surface of lower
ribs near their angles
Upper borders of
ribs 2 or
3 below
IntercostalElevates ribs
Levator
costarum
Transverse processes
of T7–T11
Subjacent ribs
between
tubercle and angle
Dorsal
primary
rami
of C8–T11
Elevates ribs
16

17. 
Spaces between the ribs
contaning:
◦External intercostal muscle
◦Internal intercostal muscle
◦Innermost intercostal muscle
(*endothoracic fascia and
pleural)
◦Neurovascular bundles:
Intercostal nerves and blood
vessels (VAN)
17

18. 
Structurespenetratedbyaneedlewhenitpassesfromskinsurfaceto
pleuralcavity.

Dependingonthesiteofpenetration,thepectoralmuscleswillbe
piercedinadditiontotheserratusanteriormuscle.
18

19. 
Skin

Subcutaneous tissue

Pectoral muscles

Serratus anterior muscle

External Intercostal muscle

Anterior Intercostal membrane

Internal Intercostal muscle

Innermost Intercostal muscle

Endothoracic fascia

Parietal pleura
19

20. 
Intercostalarteries and Veins
Eachintercostalspacecontainsalargesingleposteriorintercostalartery
(PIA)andtwosmallanteriorintercostalarteries(AIA).
◦PIAsofintercostalspace1&2arebranchesfromsuperior
intercostalartery,abranchofthecostocervicaltrunkofthe
subclavianartery.
◦PIAs
arteriesofthelowerninespacesarebranchesofthe
descendingthoracicaorta.
◦AIAsofthefirstsixspacesarebranchesoftheinternal
thoracicartery,whicharisesfromthefirstpartofthe
subclavianartery.
20

21. 
AIAs of lower spaces are
branches of the
musculophrenic artery, one of
the terminal branches of the
internal thoracic artery

Posterior intercostal veins
drain backward into the
azygos or hemiazygos veins,
and the anterior intercostal
veins drain forward into the
internal thoracic and
musculophrenic veins.
21

22. Intercostalnerves

Anteriorramiofthefirst11thoracicspinalnerves.

Anteriorramusofthe12ththoracicnerveliesintheabdomen
andrunsforwardintheabdominalwallasthesubcostalnerve.
Note:Thefirstsixnervesaredistributedwithintheirintercostal
spaces.
o7thto9thintercostalnervesleavetheanteriorendsoftheir
intercostalspacesbypassingdeeptothecostalcartilages,
toentertheanteriorabdominalwall.
oThe10thand11thnerves,sincethecorrespondingribsare
floating,passdirectlyintotheabdominalwall
22

23. 23
Branches
•Rami communicates
•Collateral branch
•Anterior cutaneous branch
•Muscular branch
•Pleural sensory branches
•Peritoneal sensory branches

24. 
First intercostal nerve
◦Joined to the brachial plexus by a large branch that is equivalent to
the lateral cutaneous branch of typical intercostal nerves.
◦The remainder of the first intercostal nerve is small, and there is no
anterior cutaneous branch.

Second intercostal nerve
◦Is joined to the medial cutaneous nerve of the arm by a branch called
the intercostobrachialnerve
◦supplies the skin of the armpit and the upper medial side of the arm.

In coronary artery disease, pain is referred along this nerve to the
medial side of the arm
24

25. 
Athinmuscularandtendinousseptumthatseparatesthechest
cavityabovefromtheabdominalcavitybelow.Itispiercedby
thestructuresthatpassbetweenthechestandtheabdomen

Partsoftheorigin
◦Sternal part: from the posterior surface of the xiphoid
process.
◦Costal part: from the deep surfaces of the lower six ribs and
their costal cartilages.
◦Vertebral part: by vertical columns or cruraand from the
arcuate ligaments.
25

26. 26

27. Branchofthefirstpartofsubclavianarterysupplyingtheanterior
wallofthebodyfromtheclavicletotheumbilicus.
Branches

2anteriorintercostalarteries(supplyupper6ICS)

Perforatingarteries

Pericardiacophrenicartery

Superiorepigastricartery

Musculophrenicartery
27

28. 28

29. Internal Thoracic Vein

Formed by the confluence of the superior epigastric and
musculophrenicveins,

Ascends on the medial side of the artery

Receives the upper six anterior intercostal and
pericardiacophrenicveins

Ends in the brachiocephalic vein.
ThoracoepigastricVein

Is a venous connection between the lateral thoracic vein and the
superficial epigastric vein.
29

30. 30

31. Sternal or Parasternal (Internal Thoracic) Nodes

Are placed along the internal thoracic artery.

Receive lymph from the medial portion of the breast, intercostal spaces,
diaphragm, and supraumbilicalregion of the abdominal wall.

Drain into the junction of the internal jugular and subclavian veins.
Intercostal Nodes

Lie near the heads of the ribs.

Receive lymph from the intercostal spaces and the pleura.

Drain into the cisterna chylior the thoracic duct.
Phrenic Nodes

Lie on the thoracic surface of the diaphragm.

Receive lymph from the pericardium, diaphragm, and liver.

Drain into the sternal and posterior mediastinalnodes.
31

32. 
Suprasternal notch:
Is the superior margin of the manubrium sterni and is easily
felt between the prominent medial ends of the clavicles in the
midline. It lies opposite the lower border of the body of the
second thoracic vertebra.

The sternal angle (angle of Louis):
Angle made between the manubrium and body of the sternum.
It lies opposite the intervertebral disc between the fourth and
fifth thoracic vertebrae.
32

33. 
XiphisternalJoint:
isthejointbetweenthexiphoidprocessofthesternumandthe
bodyofthesternum.Itliesoppositethebodyoftheninth
thoracicvertebra.

Thesubcostalangle:
issituatedattheinferiorendofthesternum,betweenthe
sternalattachmentsoftheseventhcostalcartilages.
33

34. 
CostalMargin

Lowerboundaryofthethoraxandisformedbythecartilages
ofthe7th,8th,9th,and10thribsandtheendsofthe11thand
12thcartilages.

Lowestpartofthecostalmarginisformedbythe10thriband
liesatthelevelofthethirdlumbarvertebra(L3).
34

35. 1. Clavicle
2. Suprasternal notch
3. Manubrium
4. Sternoclavicular joint
5. Body of sternum
6. Xiphisternum
7. Coracoid process
8. True ribs (1–7)
9. False ribs (8–10)
10. Costal cartilages
11. Costal margin
35
Doctorlib© 2015-2019

36. 1. Clavicle
2. Ribs
3. Left dome of diaphragm
4. Right costophrenicangle
5 Right border of heart
6 Left border of heart
7 Pulmonary conus
8 Aortic knuckle
36
Doctorlib© 2015-2019

37. 1. Midline sternotomy approach to
the mediastinum
2. Left anterolateral thoracotomy
through bed of fifth rib
3. Posterolateral thoracotomy
through bed of fourth rib
4. Thoraco-abdominal incision
5. Point for insertion of a needle
into ventricles
6. Point for insertion of a needle
into pericardial cavity for
emergency pericardiocentesis
37
Doctorlib© 2015-2019

38. AnatomicandPhysiologicChangesintheThoraxwithAging

Theribcagebecomesmorerigidandlosesitselasticityastheresult
ofcalcificationandevenossificationofthecostalcartilages.

Thestoopedposture(kyphosis),sooftenseenintheoldbecauseof
degenerationoftheintervertebraldiscs,decreasesthechestcapacity.

Disuseatrophyofthethoracicandabdominalmusclescanresultin
poorrespiratorymovements.

Degenerationoftheelastictissueinthelungsandbronchiresultsin
impairmentofthemovementofexpiration.

Thesechanges,whensevere,diminishtheefficiencyofrespiratory
movementsandimpairtheabilityoftheindividualtowithstand
respiratorydisease.
38

39. Read up the followings:

Surface markings of the lungs and heart

The pleural
39

40. 40