a-the thoracic wall
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A-THE THORACIC WALL
Posteriorly by the thoracic part of the vertebral column
Boundaries
Anteriorly by the sternum and costal cartilages
Laterally by the ribs and intercostal spaces
Superiorly by the suprapleural membrane
Inferiorly by the diaphragm, which separates the thoracic cavity from the abdominal cavity
A-THE THORACIC WALL
Posteriorly by the thoracic part of the vertebral column
Boundaries
Anteriorly by the sternum and costal cartilages
Laterally by the ribs and intercostal spaces
Superiorly by the suprapleural membrane
Inferiorly by the diaphragm, which separates the thoracic cavity from the abdominal cavity
1- STERNUM
It is a flat bone Divides into three
parts:
2-Body of the sternum
1-Manubrium sterni
3- Xiphoid process
The sternal angle (angle of Louis)
formed by the articulation of the manubrium with the body of the
sternum
second costal cartilage
The point from which all costal cartilages and ribs are counted
Lies at the level of
2-RibsThere 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:
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.
True ribs: The upper seven pairs are attached anteriorly to the sternum by 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
A rib has a head, neck, tubercle, shaft, and angle
The inferior border forms THE COSTAL GROOVE
which accommodates the intercostal vessels and nerve.
intercostal vein intercostal artery intercostal nerve
VANim
porta
nt
3-The Vertebral Column
7 cervical
is composed of 33 vertebrae
12 thoracic
5 lumbar
5 sacral (fused to form the sacrum)
4 coccygeal (the lower 3 are commonly fused)
The vertebral arch gives rise to seven processes:
a-One spinousb-Two transversec- Four articular(2 superior 2 inferior)
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
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 bordersForming
the superior and inferior vertebral notches.
These foramina, in an articulated skeleton, serve to
transmit the spinal nerves and blood vessels .
On each sidethe superior notch of one vertebra and the inferior
notch of an adjacent vertebra together form an
intervertebral foramen .
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
4-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
Main Openings in the diaphragm
Nerve supply of the diaphragm
The phrenic nerves
1-SKIN2-SUPERFISCIAL FASCIA3- THREE MUSCLES OF RESPIRATION: THE EXTERNAL INTERCOSTALTHE INTERNAL INTERCOSTAL THE INNERMOST INTERCOSTAL MUSCLE4-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)
5-Intercostal Spaces
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
LATERALLY PLACED
PLEURAE AND LUNGS
MEDIAN PARTITION
CALLED THE
MEDIASTINUM
2-PleuraeThe pleurae and lungs lie
on either side of the mediastinum within the
chest cavity
the lung is covered with visceral pleura and the thoracic
wall is lined with parietal pleura
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 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:
2 -Visceral layer :completely covers the outer surfaces of
The lungs
1 -Parietal layer, which lines A-The thoracic wall
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 BronchiThe right principal (main) bronchus
1-wider2-shorter
3 -more vertical than the left 4-is about 1 in. (2.5 cm) long
The left principal (main) bronchus is 1-narrower2-longer3-more horizontal than the right4- is about 2 in. (5 cm) long.
Inhalation of foreign bodies into the lower respiratory tract is common, especially in childrenBecause 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
INHALED FOREIGN BODIES
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
surface is the hiluma 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 heartThe posterior border is thick and lies beside the vertebral column
Right LungThe right lung is
slightly larger than the left is divided by
the oblique and horizontal fissures into three lobes:
THE UPPERMIDDLE
LOWER LOBES
Left LungThe 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
For the Practical
sessions you do need to recognize
the following
)1 ,2 & 3 (according to
their anatomical positions
1-Pulmonary artery
Superior in position
2-Pulmonary veinsInferior
in position
3-Main bronchus Posterior
in position
anteriorposterior
superior
inferior
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