Chapter 16 - Bony Thorax and Chest Flashcards
thorax
refers to the upper portion of the trunk, the chest. It consists of the 12 thoracic vertebrae, 12 pairs of ribs, and the breastbone, which is called the sternum.
jugular notch
also called the manubrial notch or suprasternal notch
true ribs
The first seven pairs of ribs
false ribs
The lower five pairs of ribs are called false ribs because they do not completely surround the thorax.
floating ribs
Ribs 11 and 12 are also called floating ribs. They have no cartilage and are not attached anteriorly.
diaphragm
The diaphragm is a large sheath of muscle that expands and contracts with breathing.
The thoracic cavity (Fig. 16.3) is divided into three parts:
two pleural cavities that contain the lungs and the space between the lungs, which is called the mediastinum.
mediastinum
The principal structures within the mediastinum are the heart, with its associated great vessels; the trachea or “windpipe”; and the esophagus.
The heart is divided into four hollow chambers:
the right and left atria, which are receiving chambers, and the right and left ventricles, which are discharging chambers.
vena cava
The vena cava is the large vein that brings oxygen-depleted blood from the body to the right atrium.
aorta
The aorta is the largest artery of the body. It leaves the heart in a superior direction and makes a “U turn” through what is called the aortic arch.
The right lung has three lobes:
superior, middle, and inferior
The left lung has only two lobes:
superior and inferior
cardiophrenic angles
The inferomedial corners
costophrenic angles
The inferolateral corners
carina
The trachea divides into right and left primary branches at the carina (tracheal bifurcation), found at about the level of the sternal angle and the T4-T5 interspace.
sthenic
The sthenic body habitus is considered to be “average.” About 50% of the population has this body type. The size, shape, and location of organs correspond to classic textbook descriptions and illustrations.
hyposthenic
The hyposthenic body type might be thought of as “slender normal.” About 35% of the population has a hyposthenic build. The organs tend to be longer, narrower, and more vertical in position.
asthenic
The asthenic body type is very slender. The organs are long and narrow, and the abdominal organs are located much lower in the body. About 10% of the population has this body type.
hypersthenic
The hypersthenic body type is a massive and stocky. About 5% of the population has this body type. The thorax is short, broad, and deep. The organs tend to be high and more horizontal in position.
Chest - PA and left lateral projections
Body position
Standing, facing IR holder.
Part position
PA
Anterior surface of chest is against upright Bucky with coronal plane parallel to IR. Backs of hands are placed on hips, and shoulders are rotated anteriorly (Fig. 16.13A). The purpose of arm position is to rotate scapulae out of the way so that they will not be superimposed on lungs. As an alternative, patients who are unsteady may wrap their arms around the Bucky to prevent movement and decrease the potential for a fall. IR is aligned so that upper margin is 1.5 to 2 inches (3.8 to 5cm) above level of spinous process of C7.
AP
Patient supine with arms at side (Fig. 16.13B). IR is aligned so that upper margin is 1.5 to 2 inches (3.6 to 5cm) above level of shoulders.
Lateral
Both arms are raised overhead, with the patient grasping opposite elbows. As an alternative, patients who are unsteady can grasp an overhead bar, if incorporated into the upright Bucky, or an intravenous pole to prevent movement and decrease the potential for a fall. Left side of body is in contact with upright Bucky, and midcoronal plane of thorax is perpendicular to center of IR (Fig. 16.15). IR placement is unchanged from PA projection.
Central ray
PA
Perpendicular to center of IR. Center point should be at the level of T7, which corresponds to the level of the inferior angle of the scapulae.
AP
Perpendicular to center of IR. Center point should be on the midsagittal plane at a level 3 inches below the jugular notch.
Lateral
Perpendicular to center of IR. Center point should be on the midcoronal plane at the level of T7.
Structures seen
Heart, lungs, and mediastinum. No rotation of the sternoclavicular joints on the PA projection (Fig. 16.14). Superimposition of the posterior ribs, indicating no rotation, on the lateral projection (Fig. 16.16).
Chest (Lung Apices)
AP Axial Projection (Lordotic Position)
Body position
Standing
Part position
Patient stands facing tube, 8 to 12 inches (20 to 30cm) in front of upright Bucky. Patient then arches back and places shoulders against Bucky. Sagittal plane is perpendicular to IR. Backs of hands are placed on hips and shoulders rotated anteriorly (Fig. 16.19). The purpose of the arm position is to rotate the scapulae out of the way anteriorly so that they will not be superimposed on lungs. IR is aligned so that upper margin is 3 inches above upper border of shoulder.
Central ray
Perpendicular to center of IR. Center point should be at the level of the midsternum.
Structures seen
Apices of both lungs, free of superimposition by the clavicles (Fig. 16.20).
UPPER POSTERIOR RIBS: AP AND AP OBLIQUE PROJECTIONS
Body position
Standing or recumbent.
Part position
AP
Supine on table or upright with posterior surface of chest against upright Bucky or grid holder (Fig. 16.21). Coronal plane is parallel to IR. Upper margin of IR is 1.5 to 2 inches (3.8 to 5cm) above level of spinous process of C7.
AP oblique
RPO position for right ribs or LPO position for left ribs. Coronal plane forms an angle of 45 degrees with IR plane (Fig. 16.22). Upper margin of IR is 1.5 to 2 inches (3.8 to 5cm) above level of spinous process of C7.
Central ray
AP
Perpendicular to center of IR. Center point should be in midclavicular line at approximate level of axillary fold.
AP oblique
Perpendicular to center of IR. Central ray enters at a point on midline of anterior surface at approximate level of axillary fold.
Structures seen
Ribs 1 through 10. Posterior portions are best seen on AP projection (Fig. 16.23); axillary portions are best seen on oblique projection (Fig. 16.24).
Upper Anterior RIBS: PA and PA Oblique Projections
Body position
Standing or recumbent.
Part position
PA
Prone on table or upright with anterior surface of chest against upright grid cabinet (Fig. 16.25). Coronal plane is parallel to IR. Upper margin of IR is 1.5 to 2 inches (3.8 to 5cm) above level of spinous process of C7.
PA oblique
RAO position for left ribs or LAO position for right ribs. Coronal plane forms angle of 45 degrees with IR plane (Fig. 16.27). Upper margin of IR is 1.5 to 2 inches (3.8 to 5cm) above level of spinous process of C7.
Central ray
PA
Perpendicular to center of IR. Center point should be in midclavicular line at approximate level of axillary fold.
PA oblique
Perpendicular to center of IR. Central ray enters at point on posterior surface midway between spine and midaxillary line of affected side at approximate level of axillary fold.
Structures seen
Ribs 1 through 10. Anterior portions are best seen on PA projection (Fig. 16.26); axillary portions are best seen on oblique projection (Fig. 16.28).
