The thoracic wall consists of the thoracic cage (rib cage) which includes 12 thoracic vertebrae, 12 pairs of ribs, costal cartilages, and the sternum. This provides support, stability, protection for thoracic organs, and facilitates breathing. The sternum has three parts - manubrium, body, and xiphoid process. Ribs can be typical or atypical. Movements of the thorax include pump handle and bucket handle. The thoracic cavity contains the lungs enveloped by pleura and heart within the mediastinum.

1. THORACIC WALL & CAVITY
PRESENTED BY SAMPADA KULKARNI
1ST MPT

2. THORACIC CAGE
▪ The thoracic cage (rib cage) is the skeleton of the thoracic wall.
▪ Structural component –
12 thoracic vertebrae with their intervertebral discs, 12 pairs of ribs and
their associated costal cartilages and sternum
▪ Function –
Provides support
stability for the upper part of the body
protection for thorax and thoracic organs
facilitates breathing
attachment for the muscles

4. SURFACE ANATOMY

5. STERNUM
The sternum consists of three distinct bony parts: flat bones
1. The manubrium
2. The body of sternum
3. The xiphoid process

6. THORACICVERTEBRAE
▪ Typical vertebrae
have vertebral bodies, arches, and
processes for muscular and
articular connections,
characteristic long spinous
processes
▪ Atypical vertebrae
(T1, T10, T11, T12) – transition
vertebrae
“whole costal facets” in place of
demifacets.

7. VERTEBRAL BODY
PEDICLEOFVERTEBRAL
ARCH
LAMINA OFVERTEBRAL
ARCH

8. COSTAL FACET OF
TRANSVERSE PROCESS
SUPERIORCOSTAL FACET
OFVERTEBRA
Atypical thoracic vertebrae

9. RIBS
▪ long, flat bones that enclose most of the thoracic cage
▪ first seven (and sometimes the 8th) cartilages attach directly and
independently to the sternum.
▪ 8th, 9th and 10th cartilages articulate with the costal cartilages just
superior to them, forming a continuous, articulated,
cartilaginous costal margin of the rib cage.

10. TYPICAL RIBS
▪ The 3rd-9th ribs are known
as typical ribs and all present a head,
neck, tubercle and body.
▪ superiorly the crest of the neck, angle
and external surface are shown.
▪ Inferiorly, the internal surface is shown
medial to where the costal groove is
located; this groove contains the
intercostal artery, vein and nerve.
▪ The distal end of a typical rib is
continuous with a costal cartilage
which articulates directly, or indirectly,
with the sternum.

11. ATYPICAL RIBS
▪ The atypical ribs (1st, 2nd, 10th-12th)
also have a head, neck and body, however
they differ by their morphology and/or
unique landmarks (e.g. attachment points
for subclavius/scalene muscles and and
grooves for subclavian vessels (1st rib),
tuberosity for serratus anterior muscle
(2nd rib).
▪ The 11th and 12th ribs are more slender
than the other ribs and lack several of the
typical landmarks seen on typical ribs

12. INTERCOSTAL SPACES
▪ spaces between the ribs
▪ mainly occupied by intercostal
muscles (internal and
external) and membranes

13. THORACIC CAGE
▪ Joints –
Xiphisternal : between xiphoid process and body of sternum
Intervertebral : between vertebrae
Sternochondral: between sternum and costal cartilages
Sternoclavicular: between manubrium and clavicles
Manubriosternal: between manubrium and body of sternum
Costochondral : between costal cartilage and rib
Costovertebral: between formed by ribs and bodies of vertebrae
Interchondral : between the costal cartilages

14. XIPHISTERNAL JOINT
▪ a symphysis between the
inferior margin of the body of
the sternum and the superior
margin of the xiphoid process

15. INTERVERTEBRAL JOINT
▪ The intervertebral joints
connect directly adjacent
vertebrae of the vertebral
column
▪ 1 symphysis & 2 facetal joints

16. STERNOCONDRAL JOINTS
▪ synovial plane joints that
attach the sternum (sterno-)
with the costal cartilages (-
chondral) of the thorax

17. STERNOCLAVICULAR JOINTS
▪ synovial saddle joint that
connects the sternum with
the clavicles
▪ It is the only direct connection
between the appendicular
skeleton of the upper limb and
the axial skeleton of the trunk.

18. MANUBRIOSTERNAL JOINTS
▪ a secondary cartilaginous joint
[ 2 bones are connected either
by fibrocartilage or hyaline
cartilage] (symphysis) between
two parts of the sternum; the
manubrium and the body of
sternum.

19. COSTOCHONDRAL JOINTS
▪ structurally classified as
primary cartilaginous joints
[bone is united to cartilage]
(synchondrosis) in which bones
are joined by hyaline cartilage.
▪ connect the sternal ends of
the ribs and their
respective costal cartilages.

20. COSTOVERTEBRAL JOINTS
▪ The costovertebral
joints are synovial joints, and
they are surrounded by joint
capsule.
▪ Articulation of the left and right
ribs with the vertebral column
(thoracic vertebrae) complete
the thoracic cage posteriorly.

21. INTERCHONDRAL JOINTS
▪ plane synovial joints between
the adjacent borders of the 6th
and 7th, 7th and 8th, and 8th
and 9th costal cartilages.

22. MOVEMENTS OFTHORAX
▪ The movements of the costocorporeal and costotransverse joints are
closely related and usually described together.
▪ ribs are relatively long, a small movement on their vertebral end will
cause movement of much larger amplitude at their sternal end. The end
result of these movements is anterior and lateral expansion of
chest during inhalation.

23. PUMP HANDLE
▪ Due to an almost vertical orientation of the costotransverse joints in
the upper six ribs, the elevation of ribs will cause the rib necks to glide
superiorly. But as the articular surfaces are notably curved, the main
movement will be the rotation of the rib heads around their antero-
posterior axes.
▪ Since the sternal ends of ribs are lower than the vertebral ones, the
elevation of ribs 1-6 will move the sternum superiorly and anteriorly.
This is referred to as the ‘pump-handle’ movement.

24. BUCKET HANDLE
▪ Ribs are curved in a way that
their middle thirds are lower
than their sternal and vertebral
ends, the rotation on 7-10 joints
will move the rib shafts
laterally, expanding the
transverse diameter of the
thorax. This is called the
‘bucket-handle’ movement.

25. THORCIC CAVITY
▪ The mediastinum is located
centrally and bordered by
two pleural cavities laterally.
▪ The mediastinum consists
of superior and inferior mediasti
nal cavities.
▪ The inferior mediastinal
cavity is
comprised of anterior, middle a
nd posterior compartments.

26. ARTERIES OFTHORACIC CAVITY
▪ Arterial: Aorta and it’s 3
branches - brachiocephalic
trunk, left common carotid, and
left subclavian arteries
▪ The aorta arises from the left
ventricle of the heart and arches
superiorly and posteriorly.

27. VEINS OFTHORACIC CAVITY
▪ Venous: Blood returning to the heart (right atrium) is either through the
superior vena cava or inferior vena cava.
▪ The superior vena cava drains blood from bilateral brachiocephalic
veins and the azygos venous system.
▪ The inferior vena cava travels a short distance after piercing the
diaphragm at the level of T8 to drain blood from the abdomen and
lower limbs into the floor of the right atrium.

28. NERVES
▪ The thoracic sympathetic trunk is a
ganglionated chain situated one on each
side of the thoracic vertebral column
▪ The first thoracic ganglion is commonly
fused with the inferior cervical ganglion
to form the cervi-cothoracic, or stellate
ganglion.
▪ The second thoracic ganglion is
occasionally fused with the first. The
remaining thoracic ganglia generally lie
at the levels of the corresponding
intervertebral discs and the intercostal
nerves.

29. MEDIASTINUM
▪ The cavity of the thorax contains the right and left pleural cavities
which are completely occupied by the lungs.
▪ The right and left pleural cavities are separated by a thick median
partition called the mediastinum.
▪ The heart lies in the mediastinum.

30. CONTENTS OFTHE MEDIASTINUM
Left lateral view

31. Right lateral view

32. THE PLEURA
▪ The spongy lungs occupying a major
portion of thoracic cavity are enveloped
in a serous cavity — the pleural caviy.
1. Pulmonary pleura
2. Visceral pleura - (i) costal
(ii) Diaphragmatic
(iii) Mediastinal
(iv) cervical

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