A-THE
A-THE THORACIC WALL
Boundaries
Boundaries
Posteriorly
Posteriorly
by
by the
the thoracic
thoracic part
part of
of the
the vertebral
vertebral column
column
Anteriorly
Anteriorly
by
by the
the sternum
sternum and
and costal
costal cartilages
cartilages
Laterally
Laterally
by
by the
the ribs
ribs and
and intercostal
intercostal spaces
spaces
Superiorly
Superiorly
by
by the
the suprapleural
suprapleural membrane
membrane
Inferiorly
Inferiorly
by
by the
the diaphragm,
diaphragm, which
which separates
separates
the
the thoracic
thoracic cavity
cavity from
from the
the abdominal
abdominal cavity
cavity
1- STERNUM
It is a flat bone
 Divides into three
parts:
1-Manubrium sterni
2-Body of the sternum
3- Xiphoid process
The sternal angle
(angle of Louis)
formed by the articulation of the
manubrium with the body of the
sternum
Lies at the level of
second costal cartilage
The point from which all costal cartilages and
ribs are counted
2-Ribs
There are 12 pairs of ribs, all of which are
attached posteriorly to the thoracic vertebrae.
The ribs are divided into three categories
according to their relation to the sternum:
True ribs: The upper seven pairs are attached
anteriorly to the sternum by their costal
cartilages
False ribs: The 8th, 9th, and 10th pairs of
ribs are attached anteriorly to each other and
to the 7th rib by means of their costal
cartilages.
Floating ribs: The 11th and 12th
pairs have no anterior attachment
Typical Rib
A typical rib is a long, twisted, flat bone
having a rounded, smooth superior
border
and
a sharp, thin inferior border
The inferior border forms
THE COSTAL GROOVE
which accommodates the intercostal
vessels and nerve.
intercostal vein
intercostal artery
intercostal nerve
VAN
A rib has a head, neck, tubercle, shaft,
and angle
3-The Vertebral Column
is composed of 33 vertebrae
7 cervical
12 thoracic
5 lumbar
5 sacral
(fused to form the sacrum)
4 coccygeal
(the lower 3 are commonly fused)
A typical thoracic vertebra
consists of:
1-a rounded body anteriorly
(body bearing)
2-a vertebral arch
posteriorly.
(protect the spinal cord)
They enclose a space called
The vertebral foramen
through which run the spinal
cord and its coverings
The vertebral arch gives rise
to seven processes:
a-One spinous
b-Two transverse
c- Four articular
(2 superior 2 inferior)
Characteristics of a Typical Thoracic Vertebra
The body is heart
shaped
The vertebral foramen
is small and circular
The spines are long
and inclined downward
Costal facets are
present on the sides of
the bodies for
articulation with the
heads of the ribs
Costal facets are
present on the
transverse processes for
articulation with the
tubercles of the ribs
The body and the vertebral arch are connected by means of pedicles
The pedicles
are notched on their
upper and lower borders
Forming
the superior and inferior
vertebral notches.
On each side
the superior notch of one
vertebra and the inferior
notch of an adjacent
vertebra together form an
intervertebral foramen.
These foramina, in an
articulated skeleton, serve to
transmit the spinal nerves
and blood vessels.
4-The diaphragm
The diaphragm is a thin
muscular and tendinous septum
that separates
the chest cavity above
from
the abdominal cavity below
The diaphragm is the most
important muscle of
respiration.
It is
dome shaped and
consists of a
peripheral muscular part
and a centrally placed tendon
Main Openings in the diaphragm
The inferior vena cava
passes through the central tendon at
approximately vertebral
level T8
The esophagus
passes through the muscular part of the
diaphragm, approximately at vertebral
level T10
The aorta passes behind the
posterior attachment of the
diaphragm at vertebral
level T12
Nerve supply of the diaphragm
The phrenic nerves
5-Intercostal Spaces
1-SKIN
2-SUPERFISCIAL FASCIA
3- THREE MUSCLES OF RESPIRATION:
THE EXTERNAL INTERCOSTAL
THE INTERNAL INTERCOSTAL
THE INNERMOST INTERCOSTAL MUSCLE
4-THE ENDOTHORACIC FASCIA
5-THE PARIETAL PLEURA.
The intercostal nerves and blood vessels run between
the intermediate (internal intercostal) and deepest
layers (innermost intercostal) of muscles
They are arranged in the following order from above
downward:
INTERCOSTAL VEIN
INTERCOSTAL ARTERY
INTERCOSTAL NERVE
(VAN)
The external intercostal muscle
the most superficial
layer.
Its fibers are directed
downward
and forward
The Internal Intercostal Muscle
forms the intermediate layer.
Its fibers are directed
downward and
backward
The innermost intercostal muscle
Forms the deepest layer
It is an incomplete muscle
layer and crosses more than
one intercostal space within
the ribs.
B-CHEST CAVITY
The chest cavity is
bounded by the chest
wall and below by the
diaphragm
The chest cavity
can be divided
into
MEDIAN
PARTITION
CALLED
THE
MEDIASTINUM
LATERALLY
PLACED
PLEURAE
AND LUNGS
2-Pleurae
The pleurae and lungs lie
on either side of the
mediastinum within the
chest cavity
FORMATION OF THE LUNGS
Each lung bud invaginates
the wall of the cavity and
then grows to fill a greater
part of the cavity
the lung is covered with
visceral pleura and the thoracic
wall is lined with parietal
pleura
The original cavity is reduced to
a slitlike space called the pleural
cavity as a result of the growth
of the lung.
Each pleura has two parts:
1- Parietal layer, which lines
A-The thoracic wall
2- Visceral layer:
completely covers the outer surfaces of
The lungs
The parietal and visceral layers of
pleura
are separated from one another
by a slit like space
The Pleural Cavity
Trachea
The trachea is a mobile
cartilaginous and membranous
tube
 It begins in the neck as a
continuation of the larynx at
the lower border of the cricoid
cartilage at the level of the
sixth cervical vertebra
ends at the carina by
dividing into right and
left principal (main)
bronchi at the level of the
sternal angle (opposite
the disc between the
fourth and fifth thoracic
vertebrae).
Principal Bronchi
The right principal (main) bronchus
1-wider
2-shorter
3- more vertical than the left
4-is about 1 in. (2.5 cm) long
The left principal (main) bronchus is
1-narrower
2-longer
3-more horizontal than the right
4- is about 2 in. (5 cm) long.
INHALED FOREIGN BODIES
Inhalation of foreign bodies into the lower
respiratory tract is common, especially in children
Because the right bronchus is the wider and more
direct continuation of the trachea foreign bodies
tend to enter
the right instead of the left bronchus
Lungs
In the child, they are pink, but with age, they
become dark because of the inhalation of dust
particles that become trapped in the phagocytes
of the lung.
The lungs are situated so that one lies on each
side of the mediastinum.
Each lung is conical, covered with visceral
pleura
Each lung has a blunt apex,
which projects upward into the
neck for about 1 in. (2.5 cm) above
the clavicle
a concave base that sits on the
diaphragm
a convex costal surface, which
corresponds to the concave chest wall
a concave mediastinal surface,
which is molded to the pericardium
and other mediastinal structures
At about the middle of mediastinal
hilum
surface is the
a depression in which the bronchi,
vessels, and nerves that form the root
enter and leave the lung.
The anterior border is thin and overlaps the heart
The posterior border is thick and lies beside the vertebral
column
Right Lung
The right lung is
slightly larger than the left
is divided by
the oblique and horizontal
fissures into three lobes:
THE UPPER
MIDDLE
LOWER LOBES
Left Lung
The left lung is
divided by a similar
oblique fissure into
two lobes:
the upper and lower
lobes There is no
horizontal fissure in
the left lung
1-Pulmonary
artery
Superior
in position
superior
3-Main bronchus
Posterior
in position
2-Pulmonary veins
Inferior
in position
posterior
anterior
inferior
For the
Practical
sessions you
do need to
recognize
the
following
(1, 2 & 3)
according to
their
anatomical
positions