Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_2853_Библиотеки_им_академика_М_И_Перельмана
.pdf
266 CHAPTER 8: The Chest: Chest Wall, Pulmonary, and Cardiovascular Systems; The Breasts
https://t.me/medicina_free
of ribs. Pulling the sternum and the rst rib upward rotates the costal ring
forward and upward. This happens by having the scaleni x the sternum and
rst rib while the contracting intercostal muscles narrow the interspaces. The
anteroposterior dimension of the thoracic cavity increases as the ribs are pull
upward and the sternum moves forward.
Increasing the transverse diameter of the thorax. In (Fig. 8-2C) the sternum and
rst rib are xed. Each rib is a separate semicircle rotating on an anteroposterior
axis. During expiration, the hoops slant downward on either side of the axis.
When the hoops are pulled upward toward the horizontal, each hoop, like the
pail handle, moves further from the center increasing the transverse dimension.
Similarly, contracting the intercostal muscles narrows the interspaces elevating
the ribs and increasing the transverse diameter of the thorax. Thus, xing the
rst rib and manubrium, and narrowing the interspaces causes rotation of each
rib, except the rst, on both an anteroposterior and a transverse axis, increasing
thoracic cavity dimensions. Movement is greatest in the lower thorax because
the lower ribs are longer and more oblique and the interspaces wider.
Increasing the vertical dimension of the thorax. The diaphragm is an elliptic
muscular sheet with a central brous aponeurosis. Its edges are xed to the
lower ribs, the center domes into the thorax. At end expiration the dome is
high, and the thoracic walls are close together (Fig. 8-2D). During inspiration, the walls diverge and the muscular diaphragm contracts lowering its
dome thereby elongating the vertical dimension of the thoracic cavity further
increasing its volume.
The Lungs and Pleura: The airways include the nasal passages and naso-
pharynx, the mouth and oropharynx, the larynx, trachea, and branches of the
bronchial tree supplying the pulmonary alveoli. The larynx is a frequent site
of obstruction, either from intrinsic swelling or by vocal cord paralysis.
The bronchial tree. The trachea bifurcates asymmetrically at the carina into
right and left mainstem bronchii. The left bronchus diverges at a greater angle
from the trachea than the right bronchus. Therefore, foreign bodies are most
likely to lodge in the right main stem bronchus. The right bronchus sends a
lobar bronchus to the three pulmonary lobes, the left bronchus branches into two
lobar bronchi. Each lobar bronchus subsequently divides into bronchopulmonary segments. Although highly variable, the upper lobes typically have 3 segments while the lower lobes have ve segments on the right but four on the left.
The heart lies caudal to the tracheal bifurcation and the aorta arches from front
to back over the left mainstem bronchus. Interposed between the aorta, trachea
and left main bronchus is the left recurrent laryngeal nerve, which descends in
front of the aortic arch, loops under it, and ascends on the lateral aspect of the
trachea into the neck. A dilated, aneurysmal aortic arch can produce a tracheal
tug by pulsating downward against the left bronchus. Similarly, a dilated aorta
as well as mediastinal adenopathy can compress the left recurrent laryngeal
nerve against the left bronchus, paralyzing the left vocal cord.
Lungs. Think of the lungs as clusters of pulmonary alveoli around subdivisions of the bronchial tree. The right lung has upper, middle, and lower
lobes. The left lung has upper and lower lobes. The lobes are separated by
Major Systems and Physiology 267
Right middle lobe
Left upper lobe
PosteriorAnterior
https://t.me/medicina_free
Right upper lobe
Right lower lobe
FIG. 8-3
The Lobes of the Lungs. The transparent diagram shows the anterior aspects of the pulmonary lobes and their
main bronchi. Note the three divisions of the right main bronchus and the more direct line with the trachea on the right side.
The dotted line shows the posterior extent of the lower lobes.
FIG. 8-4 Lung Segments. Each lobe is divided into segments. The thick lines are the anatomical fissures, readily identi-
fied on inspection of the lung and often in radiographs. The thinner lines are established only by careful dissections of injected
preparations. In the abbreviations the first capital letter designates right or left; the second, upper, middle, or lower, and the
third L i s for lobe. Note t hat the lingul a, composed of t he superior an d inferior seg ments of the le ft upper lob e, is near the hear t
corresponding in many respects to the right middle lobe.
Left lower lobe
infolded visceral pleura, the lobar ssures which limit air passage between
lobes. However, ssure variations are common and many are incomplete or
partial and permit air passage between adjacent lobes. The shape of the lungs
is molded by the rib cage peripherally and the heart centrally. The molding
indentation of medial edge of the left lung is termed the cardiac notch. Each
lobe is divided into bronchopulmonary segments, consisting of the cluster
of alveoli supplied by a single rst branch of the lobar bronchus (Figs. 8-3
and 8-4). Segments are not demarcated by ssures. However, if present, extra
ssures may follow these boundaries. The lingula of the left upper lobe is
homologous with the right middle lobe.
The pleura. The relationship of each lung to its pleura is visualized by imagining a sphere of thin plastic material from which the air is being evacuated
268 CHAPTER 8: The Chest: Chest Wall, Pulmonary, and Cardiovascular Systems; The Breasts
Parietal pleura
https://t.me/medicina_free
Visceral pleura
FIG. 8-5 Modeling the Relationship of the Pleura and Lung. Deflate a rubber or plastic sphere so that it assumes
a hemisphere with a concave and convex surface. Place a model lung in the concavity and cement the lung surface to the
inner surface of the hemisphere. On the right, in cross section, the parietal pleura is represented by the convex surface of the
hemisphere; the cemented layers represent the visceral pleura. To complete the model, exhaust the hemisphere of air, replacing it with a little fluid to lubricate the inner surface. This geometry should be visualized while examining the chest and when
looking at radiographs, remembering that the pleural surfaces are anterior, lateral, medial, and inferior.
(Fig. 8-5). As the sphere collapses, one-part invaginates forming a hollow
hemisphere with convex and concave layers in apposition. The convex layer,
representing the parietal pleura, is cemented to the inside of the thoracic cavity. The lung lls the concavity, which represents the visceral pleura. The parietal pleura is adherent to the thoracic wall; the visceral pleura is xed to the
lung surface and lines the interlobar ssures. The two apposing layers form
the pleural cavity, containing only enough uid for lubrication. The parietal
pleura has the greater area, extending inferiorly on the ribs and diaphragm
some distance below the lower tip of the lung forming the costophrenic sinus.
This permits the lungs to move within the thoracic cavity, each descending
part way into this sinus during deep inspiration. Between the two layers of
pleura is a potential space, normally with a negative pressure relative to the
atmosphere. This negative pressure maintains lung distention and transfers
the inspiratory forces of diaphragm attening and chest expansion to the
lung. Air in this space, pneumothorax, destroys mechanical coupling of chest
motion to lung expansion. The parietal pleura contains sensory nerve endings, but the visceral pleura is anesthetic.
Lung and pleura mechanics. When a normal lung is removed it partially
collapses from its elastic recoil becoming much smaller than its hemithorax.
Normal lung volume is maintained by adherence to the thoracic wall of the
parietal and visceral pleurae. Atmospheric pressure resists any force tending
to separate the pleural layers. During passive expiration, about negative –4
to –5 cm of water intrapleural pressure is maintained by elastic recoil of the lung
and thorax. During inspiration, the pleural pressure decreases further to –8
to –10 cm of water because additional elastic recoil is produced by stretching
the lung as the thorax expands.
The Cardiovascular System
The circulation. The circulatory system includes the heart, the blood and its
conducting vessels, the lymph and its ducts, and the vessel walls. Since the
heart and much of the aorta are intrathoracic, consideration of the circulatory
system starts in the chest. Blood returning from the extremities enters the
chest from the abdomen and lower extremities via the inferior vena cava (IVC),
and from the arms and head via the axillary and jugular veins, which merge
Major Systems and Physiology 269
https://t.me/medicina_free
into the brachiocephalic veins and superior vena cava (SVC) in the mediastinum.
The heart is suspended from the great vessels (aorta, pulmonary artery, pulmonary veins, IVC, and SVC) within the pericardium, allowing the heart free
motion during ventricular contraction.
The cardiac conduction system. The heart’s normal pacemaker is the sino-
atrial (SA) node located in the right atrial wall near the entrance of the SVC
(Chapter 4, Fig. 4-1, page 54). It originates rhythmic waves of excitation that
spread quickly through both atria until they reach the atrioventricular (AV)
node near the posterior margin of the interatrial septum. The AV-node delays
conduction during atrial systole. The impulse then passes down the bundle
of His, which divides into right and left bundle-branches to the muscle of the
right and left ventricles via the Purkinje network. Normal conduction is very
rapid, arriving nearly simultaneously in both atria, and, after AV delay, in
both ventricles. Deviations in the timing or pathways taken by these electrical
waves cause changes in rate, rhythm, and electrical pattern of the P, QRS, and
T waves of the electrocardiogram (ECG). The electrical signals trigger mechani
cal muscle contraction via the process of electrical–mechanical coupling.
Heart movement and function. Because myocardial muscle bers form a
complete spiral, contraction during systole decreases all cardiac dimensions.
The apex rotates forward and to the right, approaching the chest wall and
frequently causing a visible and palpable thrust, the apical impulse, in early
systole marking the palpable onset of cardiac contraction. The heart has
extremely high oxygen and energy requirements and the highest oxygen
extraction of any organ. As a result, it is particularly sensitive to decreased
blood ow. Blood ow within the heart and lungs is dependent upon complete functional separation of the cardiac chambers by intact interatrial and
interventricular septa and functional valves. Valve closure, turbulent blood
ow, and heart contraction can be felt and auscultated through the chest wall.
-
Peripheral arteries. Blood is distributed to the body through the major
branches of the aorta, which are easily examined where they leave the chest
(carotid and axillary arteries) or abdomen (femoral arteries). Blood pressure
measurement and an estimate of blood ow are easily performed by physical
examination.
Leg veins. Knowledge of normal leg vein functional anatomy has many
clinical applications including differentiation of supercial from deep venous
thrombosis and surgical planning. The great saphenous vein begins at the
mediodorsal side of the foot, continuing upward along the medial edge of the
tibia, and passing the knee behind the medial femoral condyle. In the thigh, it
runs subcutaneously to the femoral canal, emptying into the femoral vein. The
small saphenous vein begins at the lateral side of the foot, curving under and
behind the lateral malleolus, continuing upward in the posterior midline, and
nally diving into the popliteal vein. Valved communicating veins connect the
saphenous veins to the deep calf veins and the great saphenous to the femoral
vein. Supercial veins course through the cutaneous and subcutaneous tissues and are not surrounded by muscle. In contrast, deep veins by convention are completely surrounded by muscle. Normal ow is from supercial
to deep veins and thence proximally driven by skeletal muscle contraction
compressing the veins within the muscle compartments (the muscle pump).
270 CHAPTER 8: The Chest: Chest Wall, Pulmonary, and Cardiovascular Systems; The Breasts
Head of clavicle
https://t.me/medicina_free
Antegrade ow is assured by competent venous valves. Thrombosis in
supercial veins is less likely to embolize because of the absence of muscular
compression while deep venous thrombosis typically is associated with high
potential to embolize into the vena cava and pulmonary arteries.
SUPERFICIAL THORACIC ANATOMY
The Chest Wall: The sternum’s subcutaneous anterior surface has landmarks
used in inspection and palpation. The heads of the clavicles are the sides
of the suprasternal notch, its base is the superior edge of the manubrium
(Figs. 8-1 and 8-6). The junction of the manubrium and body, (gladiolus),
where the second rib articulates, forms the sternal angle (angle of Louis), a
landmark for identifying ribs and interspaces. At the inferior end of the sternal body a slight depression, the infrasternal notch, is formed by the junction of
the 7th rib costal cartilages. The xiphoid cartilage is palpable below this notch.
The bony thorax is a truncated cone narrowing superiorly. This narrowing is partially obscured by the overlying clavicles, shoulders, and upper
chest and arm muscles giving the body a broad shouldered, squared-off contour. The clavicles, sternum, and lower ribs are palpable in most patients with
normal body mass; portions of most other ribs can be seen or palpated. The
rst rib is overlaid by the clavicle. The pectoralis major and female breasts
limit palpation of ribs anteriorly, and the latissimus dorsi covers some ribs
behind the axilla. The scapulae, overlying the posterior chest wall lateral to
the spine, cover parts of the second through seventh ribs. With the arms at the
sides, the inferior scapular angle is at the seventh or eighth intercostal space, a
landmark for counting ribs posteriorly (Fig. 8-7). Bilaterally, the inferior margins of the seventh, eighth, and ninth costal cartilages meet in the midline
forming the infrasternal angle (intercostal angle). An oblique line drawn from
the head of the clavicle to the anterior axillary line on the ninth rib approximately locates the costochondral junctions of the second to tenth ribs. The lower
ribs with large radii, supercial location, and extensive anterior cartilage are
vulnerable to injury. Upper ribs are less susceptible to mechanical injury
because of their smaller radius of curvature and overlying muscles.
First rib
Manubrium sterni
Second rib
Angle of Louis
Anterior
FIG. 8-6 The Angle of Louis. The adjacent edges of the manubrium and gladiolus form the angle of Louis. This is a
landmark for counting ribs anteriorly because the second rib abuts the junction that forms the angle. The costicartilage of
the second rib articulates with the fibrocartilage between the manubrium and the body and with the edges of both bones.
Lateral
Supercial Thoracic Anatomy 271
Eighth intercostal space
2nd rib
Anterior Right Left Posterior
https://t.me/medicina_free
Clavicle
Scapular spine
Eighth rib
Inferior scapular angle
FIG. 8-7 Surface Landmarks of the Posterior Thorax. Note the relation of the scapulae to the ribs. The inferior
angle of the scapula is usually at the eighth interspace allowing identification of the eighth rib posteriorly for counting
posterior ribs.
4th rib
6th rib
FIG. 8-8 Topography of the Five Lobes of the Lungs. The solid lines are the pulmonary fissures; the broken lines
are projections. The boundary of the lingula (L) is hypothetical.
The scapula is overlaid with skeletal muscle and glides on the chest wall.
Its medial border, inferior angle, lateral border, spine, acromion, and coracoid
process are palpable in most patients with normal body mass. The lungs
extend to the thoracic apex and may extend superiorly into the base of the
neck where they are vulnerable to penetrating injury. The right and left pleural spaces coapt in the anterior superior mediastinum but are separated posteriorly by the spine and mediastinum and anteriorly and inferiorly by the
pericardial sack and heart. The heart lies retrosternally and to the left with
the right ventricle retrosternal and the left ventricle left lateral and posterior.
The liver and spleen are below the diaphragm deep to the lower ribs. Deep
inspiration attens the diaphragm pushing them toward the costal margins
where the liver and an enlarged spleen can be palpated. The axillary folds are
formed by the pectoralis major anteriorly and the subscapularis and latissimus dorsi posteriorly.
The Lungs and Pleura: The topography of the ve lung lobes has some clini-
cal applications. In Figure 8-8, note that the anterior aspect of the right lung
272 CHAPTER 8: The Chest: Chest Wall, Pulmonary, and Cardiovascular Systems; The Breasts
(usual)
https://t.me/medicina_free
Midclavicular line
Aorta
Left ventricle
Pulmonary
artery
Right atrium
FIG. 8-9
Precordial Projections of the Anterior Surface of the Heart. T he entire cent ral area of the precordiu m
is a projection of the right ventricle. The left border and apex are formed by the left ventricle; the right atrium is the right
border.
Right ventricle
A. Right lateral
D. PA
FIG. 8-10 X-ray Silhouettes of the Heart. The positions are named for the aspect of the patient’s thorax that faces
the cassette (except for the PA view). Angles are measured between the direction of the X-ray beam and the plane of the
patient’s back. The heavy lines on the silhouettes indicate distinctive segments used in diagnosis.
B. Right anterior
oblique (30°)
E. Left anterior
oblique (60°)
C. Right anterior
oblique (60°)
(usual)
F. Left anterior
oblique (30°)
Physical Exam of The Chest and Major Vessels 273
https://t.me/medicina_free
is formed almost entirely of the right upper and middle lobes, the posterior
aspect containing only the upper and lower lobes. In the left lung, the upper
and lower lobes present both back and front.
The Heart and Precordium: The anterior chest over the heart and aorta is the
precordium, normally extending vertically from the second to the fth intercostal space and transversely from the right sternal border to the left midclavicular line in the fth and sixth interspaces. With an enlarged or displaced
heart, the precordial boundaries shift. In dextrocardia, all signs described here
are in the opposite hemithorax.
Figure 8-9 depicts the normal heart’s projection on the precordium, and
Figure 8-10 shows the basic projections on chest X-rays and uoroscopic
imaging used during coronary angiography. The aortic arch lies behind the
manubrium. The sternum’s right edge, from the third to fth interspaces, is
roughly the right heart border formed by the right atrium. The right ventricle
lies anteriorly under the sternum and left lower ribs. The left ventricle, forming the cardiac apex and a slender area of the left heart border, sits posterior to
the right ventricle. Thus, the right ventricle forms most of the heart’s anterior
surface but neither right or left heart border.
PHYSICAL EXAM OF THE CHEST AND MAJOR VESSELS
Inspection of the Rib Cage and Thoracic Musculature
Chest wall. With the patient upright or supine, inspect the chest wall from the
foot of the bed looking for structural deformities that might restrict respiratory
excursion. Observe several respiratory cycles noting the amplitude of chest
movement, respiratory rate and rhythm. Look for signs of respiratory distress including labored inspiration with visible contraction of sternocleidomastoid muscles during inhalation and contraction of abdominal musculature during forced exhalation. Observe for other signs of respiratory
compromise including sternal notch retractions, intercostal retraction, and
paradoxical abdominal movements in which the abdomen moves upward
and into the thorax during inhalation rather than downward and outward.
Palpating with the palms can conrm asymmetric and dyskinetic chest wall
motion.
Thoracic spine. With the patient standing or sitting, inspect the spine’s cervical, thoracic and lumbar curves from the side. Observe for exaggerated,
smooth forward curvature, (kyphosis), focal or angular, sharp forward curvature, (gibbus deformity), and exaggerated backward curvature of the lumbar
spine, (lumbar hyperlordosis). From the back, assess the spine for straightness in the cranial to caudle dimension. Observe for lateral curvature of the
spinous processes indicating scoliosis. To accurately detect and characterize
the degree of scoliosis, palpate and mark each spinous process. The complete
spine exam is described in Chapter 13 on page 539.
Palpating the Rib Cage and Thoracic Musculature
Trachea. Check for tracheal deviation by placing your index nger in the
suprasternal notch and judging the space between the clavicles and each lateral tracheal border. Alternatively, feel for the tracheal rings in the middle
274 CHAPTER 8: The Chest: Chest Wall, Pulmonary, and Cardiovascular Systems; The Breasts
https://t.me/medicina_free
of the suprasternal notch. If the apex of the rings touches the middle of the
ngertip, the trachea is midline.
Thoracic wall. Palpate if there is chest tenderness, subcutaneous emphysema,
(air crepitus), cysts or masses, breast lumps, or draining sinuses. Examine the
soft tissues and large thoracic muscles for tenderness. If tender, characterize
the movements that increase or diminish pain. Examine the costal cartilages
and palpate the costochondral junctions and xiphisternal joint for tenderness.
Palpate the ribs for point tenderness, swelling, bony crepitus, and pain on
chest compression.
Testing upper chest excursion. Place a hand over the clavicle on each side of
the patient’s neck with palms against the upper anterior chest wall and curl
the ngers rmly over the superior edges of the trapezii. Then extend your
thumbs so their tips meet in the midline (Fig. 8-11A). Have the patient inspire
deeply permitting your palms to move freely with the chest while your ngers are anchored on the trapezii. The upper four ribs move forward with
inspiration, the thumbs diverging laterally an equal distance. Asymmetric
excursion suggests a lesion on the lagging side in the chest wall, pleura, or
upper lobe of the lung.
Testing midchest excursion anteriorly. With ngers high in each axilla and
thumbs abducted, place the palms rmly on the anterior chest. Move the
hands medially, dragging skin to provide slack until the thumb tips meet in
the midline at the level of the sixth ribs (Fig. 8-11B). Have the patient inspire
deeply letting your hands follow the chest movements. The thumbs should
move apart. A unilateral lag indicates a lesion in the wall, pleura, middle lobe
of the right lung, or lingula of the left lung.
Testing lower chest excursion posteriorly. The patient sits or stands with his
back toward you. Place your ngers in each axilla, with the palms applied
rmly to the patient’s chest, so your index ngers are one or two ribs below
the inferior scapular angles. Provide slack by pressing the soft tissues while
pulling your hands medially until your thumbs meet over the vertebral spines
(Fig. 8-11C). Have the patient inspire deeply, following the chest movements
with your hands; your thumbs should move apart. A unilateral lag indicates
a lesion in the wall, pleura, or lower lobes.
Testing costal margin excursions. With the patient supine, place your
hands so the extended thumbs lie along the inferior edges of the costal margins, with their tips nearly touching (Fig. 8-11D). Have the patient inspire
deeply, letting your thumbs follow the costal margins. Normally, the thumbs
diverge. Diminished divergence or convergence indicates attening of the
diaphragm.
Examining the Lungs and Pleura: Examination of the lungs and pleura is
necessary to screen for subclinical thoracic disease and in the initial evaluation of all patients with suspected cardiopulmonary disease. Accurate classication of breath sounds, cardiac sounds, chest percussion and assessment
of tactile fremitus establish the likelihood of signicant disease, permit initial
Physical Exam of The Chest and Major Vessels 275
of posterior thorax
of costal margins
https://t.me/medicina_free
A. Testing of upper thorax B. Testing of expansion
of midthorax
C. Testing of expansion
FIG. 8-11 Testing Thoracic Movement. A. The upper anterior thorax. B. Expansion of the anterior mid-thorax.
C. Expansion of the posterior thorax. D. Movement of costal margins.
characterization of disorders and provide essential context for accurate interpretation of imaging studies. Importantly, diagnostic imaging of the chest is
static and cannot provide complete information on airow, blood ow and
musculoskeletal dynamics. Physical exam is rapid, can be performed in all
clinical situations, and does not require additional equipment or remove caregivers from the patient. Some life-threatening conditions must be identied
rapidly and primarily by physical exam such as central airway obstruction,
tension pneumothorax, asthma, and pericardial tamponade. Other conditions
require concurrent physical examination and imaging studies for accurate
classication including musculoskeletal trauma and pleural effusions.
D. Testing movements
Соседние файлы в папке Библиотека им академика М.И. Перельмана