Download October 6, 2010

October 6, 2010
Jarvis 436-439
Harbinder Minhas
Position and Surface Landmarks
Thoracic cage
-bony structure with a conical shape, which is narrower at the top
-defined by the sternum, 12 pairs of ribs, and 12 thoracic vertebrae
-It’s floor is the diaphragm-a musculotendinous septum that separates the thoracic cavity
from abdomen
-the first seven ribs attach directly to the sternum via their costal cartilages
-ribs 8, 9 & 10 attach to the costal cartilage above and ribs 11 & 12 are “floating” with
free palpable tips
-the costochrondial junctions are the points at which the ribs join their cartilages. They
are not palpable
Refer to Fig 18-1 p 436 Jarvis (google image below of similar fig 18.1 p 436 in txt)
Anterior Thoracic Landmarks:
-surface landmarks on thorax are signposts for underlying respiratory structures
-Suprasternal Notch: hollow U-shaped depression just above the sternum, in between
clavicles
-Sternum: The breastbone, has 3 parts-manubrium, the body, xiphoid process
Manubriosternal Angle: often called the sternal angle or the “angle of Louis” this is the
articulation of the manubrium and body of the sternum and is continuous with the second
rib
-angle of Louis also marks the site of tracheal bifurcation into the right and left main
bronchi
-angle of Louis corresponds with the upper border of the atria of the heart, and lies above
the fourth thoracic vertebra on the back
Costal Angle
-the right and left costal margins form an angle where they meet at the xiphoid process
-usually 90 degrees or less, this angle increases when the rib cage is chronically
overinflated, as in emphysema
Posterior Thoracic Landmarks: (Fig 18-2, p 437)
-Vertebra Prominens: Start here. Flex your head and feel for the most prominent bony
spur protruding at the base of the neck.
-This is the spinous process of C7. If two bumps seem equally prominent, the upper one
is C7 and the lower one is T1.
-Spinous Processes: Count down these knobs on the vertebrae, which stack together to
form the spinal column
-spinous processes align with their same numbered ribs only down to T4. After T4, the
spinous processes angle downward from their vertebral body and overlie the vertebral
body and rib below.
Inferior Border of the Scapula: The scapulae are located symmetrically in each
hemithorax. The lower tip is usually at the 7th or 8th rib
Twelfth Rib: Palpate midway between the spine and the person’s side to identify its free
tip.
Reference lines:
-use reference lines to pinpoint a finding
vertically on the chest.
-On the anterior chest, note the
midsternal line and the midclavicular line
-the midclavicular line bisects the centre
of each clavicle at a point halfway
between the palpated sternoclavicular
and acromioclavicular joints
Fig 18-3 p.437 Jarvis
The posterior chest wall has the vertebral
(or midspinal) line and the scapular line,
which extends through the inferior angle
of the scapula when the arms are at the
sides of the body
Fig 18-4 p.438 Jarvis
Lift up the person’s arm 90 degrees, and
divide the lateral chest by three lines:
The anterior axillary line extends down
from the anterior axillary fold where the
pectoralis major muscle inserts
The posterior axillary line continues
down from the posterior axillary fold
where the lattissimus dorsi muscle inserts
The midaxillary line runs down from the
apex of the axilla and lies between and
parallel to the other two.
Fig 18-5 p.438 Jarvis
The Thoracic Cavity:
-The mediastinum is the middle section of the thoracic cavity containing the esophagus,
trachea, heart and great vessels.
-The right & left pleural cavities, on either side of the mediastinum, contain the lungs
Lung Borders:
-In the anterior chest, the apex or highest point of lung tissue is 3 or 4 cm above the inner
third of the clavicles
-the base, or lower border, rests on the diaphragm at about the 6th rib in the midclavicular
line.
-laterally, lung tissue extends from the apex of axilla down to the 7th or 8th rib
-posteriorly, the location of the C7 marks the apex of lung tissue, T10 corresponds to the
base
-deep inspiration expands the lungs and their lower border drops to level of T12.
Lobes of the Lungs:
-the lungs are paired but not symmetrical structures
- the right lung is shorter than the left lung because of the underlying liver
-the left lung is narrower than the right lung because the heart bulges to the left
-right lung has 3 lobes
-left lung has 2 lobes
-these lobes are not arranged in horizontal bands like dessert layers in a parfait glass
-they are separated by fissures that run obliquely through the chest
Anterior
-the oblique (major or diagonal)
fissure crosses the 5th rib in the
midaxillary line and terminates at the
6th rib in midclavicular line
-the right lung also contains
horizontal (minor) fissure, which
divides the right upper and middle
lobes
-this fissure extends from the 5th rib
in the right midaxillary line to the 3rd
intercoastal space or 4th rib at the
right sternal border
Fig 18-6 p 439 Jarvis
Posterior
-almost all lower lobe
-the upper lobes occupy a smaller
band of tissue from their apices at T1
down to T3 or T4.
-at this level, the lower lobes begin
and their inferior border reaches
down to the level of T10 on
expiration and T12 on inspiration
Fig 18-7 p 439 Jarvis