- Cervical ribs
+) These develop
from persistent costal elements of c7
+) Articulate with the seventh cervical vertebra.
+) May be bony, cartilaginous
or fibrous.
+) May compress (or overstretch) the subclavian artery and or lower trunk of
the brachial plexus
- Lumbar ribs
+) Are more common than cervical ribs.
+) They articulate with the first lumbar vertebra or are attached to
tips of the transverse process.
+) May confuse the identification of vertebral levels
in radiographs.
+) May be erroneously interpreted
be intepreted as a fracture of a lumbar transverse process.
 Bifid ribs : Can cause confusion in rib count
Fused ribs are uncommon, and are often associated
with a vertebral abnormality e.g. a hemi vertebra
Rib Fractures:
- Commonest site just anterior to the angle: area of greatest change in curvature
- Becausef
the ribs in infants and children are elastic, they do not often
fracture.
- Broken ends
may be driven inwardly and injure the thoracic and or abdominal
organs- lungs, spleen and liver
- The middle ribs are the most commonly fractured. The first
two ribs (which are partially protected by the clavicle) and the
last two (which are free and movable) are the least commonly injured.
- Fractured ribs are very painful because of their movements during
respiration, coughing and sneezing. Patients experience considerable
pain in the region of the fracture, when asked to take a deep breath.
Careful palpation along the broken rib often reveals tenderness
even when the fracture may not be visible on a radiograph.
- When a sizeable segment of the anterior or lateral chest wall is
freely movable, because of multiple rib fractures; this is called flail chest (‘ stove in chest' ). The loose segment of the
chest wall moves paradoxically i.e. inward in inspiration; and outward
in on expiration.
Thoracotomy: This is opening of the thoracic wall e.g. to remove a collection of pus or fluid in the pleural cavity
Sometimes a piece of rib is used for autogenous
bone grafting e.g. for reconstruction of the mandible following
excision of a tumor. Following the operation, the rib defect generates
from the remaining periosteum
The costal cartilages of young people provide resilience
to the thoracic cage, preventing many crushing injuries or direct
blows from fracturing the ribs and or sternum. Adults loose this
protection, when the cartilage ossifies
Separation of a rib refers to dislocation of the
costochondral junction between the rib and its costal cartilage;
and not the lack of continuity in the shaft.
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- Fracture of the sternum is
uncommon except in automobile accidents, and when drivers'
chest is driven into the steering wheel. In this case, the body of
the sternum is commonly fractured in the region of the sternal angle and is often a comminuted fracture (broken into pieces). Fortunately,
the ligaments coverings confine the fragments in most cases so that
compound (open) fractures are prevented. In severe accidents, the
body of the sternum seperates from the manubrium at the manubrosternal
joint and is driven posteriorly, rupturing the aorta and or injuring
the heart and liver. Such injury may kill from excessive loss of blood
or damage to the myocardium
- Men in their early forties, when they suddenly detect
their ossified xiphoid process, may consult the doctor for fear that
they developed a cancer in the stomach.
- The sternum contains readily accessible bone marrow,
which can be obtained by inserting a wide bone needle through the
cortex of the sternum and aspirating. The needle goes through the
skin , superficial fascia and periosteum of the sternum. This is called
sternal puncture and
is a potentially dangerous procedure which must be done carefully
otherwise the needle may go as far deep and injure the aorta and or
the heart
- Access to the anterior mediastinum may be gained
by splitting the sternum in the median plane. This is called median
sternotomy.
- The sternum develops as two separate Sternal bauds,
which unite in the middle. The union may be incomplete, causing cleft
sternum . Extensive cleft sternum may lead
to exposure of the heart (which is commonly abnormal). This is called
ectopic cordis and
is fortunately rare.
- More commonly, is a sternal foramen,
which care must be taken not to confuse it with a bullet wound. Otherwise
such a foramina when small are of no clinical consequence
- The sternum may protrude out, like a pigeon chest (pectus carinatum)
or project inferiorly and posteriorly like a funnel (pectus escavatum).
These abnormalities are usually congenital and by altering the geometry
of the chest, may interfere with normal respiratory movement. Pectus
carinatum, for example is more subject to trauma.
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- During respiration, there is considerable movement
of the various joints of the thorax (costovertebral; costochondral
and sternocostal). Hence any disorder that reduces the mobility of
these joints interferes with respiration.
- A number of areas of the thoracic cage are affected
by age changes, which compromise the normal respiration in the elderly.
These include:
- Partial or complete ossification of the costal
cartilages
- Fusion of the manubriosternal joint
- Ossification of the xyphoid process and its fusion
with the body of the sternum
- Osteoarthritic changes in the costovertebral
joints
- The shape of the thorax may be distorted by abnormalities
of the chest wall- sternum, ribs or vertebral column e.g. pectus carinatum ,
pectus cavum , scoliosis , kyphosis. These result in a considerable
change in the shape of the thorax.
- Congenital or acquired abnormalities of the diaphragm
affect breathing movements. Paralysis of half of it
does not affect the other half because each half has a separate nerve
supply.
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Because the apex of the lung extends into the neck,
infections , trauma or wounds in the posterior
triangle of the neck
may involve the lung. In addition, auscultation of the lungs must
include the root of the
neck superior to the medial third of the clavicle,
in order that sounds in the apex of the lung may be heard.
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Knowledge of the branching of the bronchial tree is necessary to determine the appropriate postures for
draining infected
areas of the lung e.g. when a patient with brochiectasis (dilation
of bronchi) is positioned
in bed on his or her left side, secretions
from the right lung and bronchi flow towards the carina of the
trachea.
Since this is a sensitive area, the cough reflex is stimulated and
the patients brings up purulent
sputum , clearing the right
bronchial tree. Alternatively, persons with bronchiectasis of the
lingula of the left
superior lobe, drain into it by lying on the right
side. The basal bronchi may be cleared by the patient
standing on
his or her head for several minutes every morning to promote drainage
of the lungs. In the
prone position (face downwards), the trachea slopes downwards
and promotes drainage while the usual
supine position one assumes
in bed with the head slightly elevated by a pillow is poor for lung
drainage.
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Bronchogenic carcinoma, is
one of the most common cancers in men. It is highly positively associated
with
cigarette smoking, and environmental pollution. The arrangement
of the lymphatics is such that these
tumors may metastasise to the
pleura; hila of the lungs; the mediastinum and from there to distant
sites.
Involvement of the closely related phrenic nerve by the tumour
results in paralysis of half of the diaphragm.
in the lower neck, involvement of the sympathetic chain and brachial
plexus causes Pancoas's syndrome.
Because
of the intimate relationship of the recurrent laryngeal nerve to the
apex of the lung, this nerve may
be involved in apical lung cancers
resulting in hoarseness of the voice owing to paralysis of a vocal
fold.
common sites of hematogenous metastasis of cancer cells from a bronchogenic
carcinoma are the:
- Brain
- Bones
- Suprarenal glands
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Supraclavicular lymph nodes are enlarged and hard
when a patient has a carcinoma of the bronchus (or
of the stomach) owing
to metastasis from the primary tumour. The supracavicular lymph nodes
are commonly
referred to as sentinel nodes because enlargement
of them alerts the examiner to the possibility of malignant
changes
in the thoracic and or abdominal organs. A tumor may invade the pleura and produce a pleural
effusion. This exudate
may be bloody and contain exfoliated cancer cells.
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Pulmonary embolism may occur,
for example following fracture or other injury of the lower limb.
It is a
frequent cause of death. Embolic obstruction of a pulmonary
artery produces a sector of lung which is
ventilated but not perfused.
A large embolus may occlude the pulmonary trunk or one of its main
branches.
The patient suffers acute respiratory distress, and may
die in a few minutes. A medium sized embolus may
block an artery to
a bronchopulmonary segment producing an infarct. In healthy young
people, collateral
circulation may prevent this infarction. But in
sick people, with already compromised pulmonary circulation,
infarction
is almost always the result.
Because an area of visceral pleura is also deprived of blood, it becomes
inflamed (pleuritis) and rough
resulting in pleuritic pain and friction
rub.
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The copolae of pleura, and the apices of the lungs,
project superiorly into the neck, posterior to the
sternocleidomastoid
muscles and into the posterior triangle of the neck. Medially, these
are related to the
roofs/trunks of the brachial plexus and the sympathetic
chain. Consequently, apical bronchogenic
carcinoma can compress
these structures giving both autonomic and somatic neurological deficits.
This is the
Pancoast's syndrome. Additionally, such cancers can also
compress the structures in the thoracic inlet,
leading to the thoracic
inlet syndrome. By its extension into the neck, wounds in the posterior
triangle of
the neck can affect the pleural cavity and the lung, and
infections may also spread upwards. In “radical”
block dissection
of the neck for tumor, care must always be taken not to open the pleural
cavity.
2) The pleurae descend inferior to the costal margin in
three regions.
- The right infrasternal angle.
- The left costovertebral angle.
- The right costovertebral angle.
At these sites, an abdominal incision might inadvertently
enter a pleural sac. In cases where the 12 th rib is
very short, the
pleura lies inferior to the posterior costal margin after crossing the
11 th rib, and is therefore in
surgical danger.
3)Fluid in the pleural cavity
- Empyema thoracis/pyothorax- pus .
- Hemothorax - Air occur, a condition known as
- Haemopneumotorax- blood and
air
- Chylothorax-chyle
4) Fluid can be drained from a pleural cavity by inserting
a wide-bore needle through an intercostal space- usually i
n the posterior
axillary line in the seventh intercostal space. The procedure of aspirating
fluid from the pleural
cavity is called a pleural tap . Sometimes, a
canula may be retained in the pleural cavity for continous drainage
of
the fluid. The canula is usually connected to an under water seal
bottle.
5) Sometimes, to prevent troublesome recurrent spontaneous
pneumothorax due to lung disease, the visceral and
parietal layers of
pleura may be purposely fused. The surgical procedure of surgically
fusing the pleurae is called
pleural poudrage . In this procedure, adherence
of the two layers is induced by covering the opposing pleural
surfaces
with a slightly irritating powder.
6) Inflammation of the pleura (pleuritis or pleurisy) causes
the pleural surfaces to become thickened and/or
rough. During breathing,
a friction rub(pleural tub) may be heard with a stethoscope. Pleuritis,
usually leads to
formation of pleural adhesions between the parietal
and visceral pleurae. In extreme cases, in chronic
inflammation of the
pleurae may cause the adhesion of the two layers, with subsequent thickening
. Calcification of
this thickened pleura is known.
7) Irritation of the parietal pleura causes pain, worse on
inspiration. The pain is usually referred to the
thoracoabdominal wall
due to common innervation by the intercostal nerves; or to the shoulder
and the side of
the neck due to shared spinal cord segments with the phrenic
nerve(C3,4,5).
Bronchopulmonary segments
- Benign bronchial and pulmonary disorders tend to be localised
in individual segments.
- Each segment is amenable to independent surgical removal except in malignancy and TB
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