SURFACE ANATOMY OF THORACIC VISCERA
I. DIAPHRAGM
A. Position obviously varies with respiration
B. Forced expiration, supine posture
1. Right dome - rises to ICS4
2. Left dome - rises to ICS5
C. Quiet respiration - one ICS lower
D. Erect posture - may be as much as one ICS lower than supine posture
E. Central tendon - level of xiphisternal junction
F. Peripheral location - costal margins
G. Innervated by the Phrenic nerve (C3-5)
II. HEART
A. Apex beat (cardiac impulse) - only visible and palpable part of the heart in the precordium
1. Located in ICS5, just medial to the midclavicular line (or 9 cm from the midline)
2. Movement caused by apex "hitting" precordium during outline
3. In deep inspiration, in ICS6
4. Sometimes an epigastric beat reflects systole
B. Cardiac outline - D:\DCIM\images\fig147.gif
1. Right border - approximately 1/2 inch (1cm) right of sternal margins
a. upper extent - R3
b. lower extent - R6
c. slightly more lateral at R4
d. above R3, same line marks projection of s. vena cave
2. Left border
a. upper extent - R3 or ICS2 near sternal margin
b. lower extent - apex location
3. Inferior margin - convex upward along diaphragm
4. Superior margin - between the two R’s 3
5. Clinical "base of heart" - near upper border over aortic and pulmonary trunks
C. Valves of heart
1. Generally lie along oblique line between right inferior left superior extent of heart
2. Pulmonary valve
a. located behind left edge of sternum, R3 level
b. best heard in ICS2 just to left of sternum
3. Aortic valve
a. located behind left edge of sternum, ICS3 level
b. best heard - R2 at right sternal border
4. Mitral (bicuspid) valve
a. located behind left edge of sternum, R4 level
b. best heard near at the apex
5. Tricuspid valve
a. located behind mid sternum at level ICS4
b. best heard near its surface projection
6. Heart sounds
a. lub = closure of a-v valves
b. dub = closure of semilunar valves
c. no sounds associated with valves opening
d. systole between lub and dub
e. diastole between dub and next lub
D. Percussion of the heart
1. Difficult because of sternum and some space or lung between body wall and heart
III. GREAT VESSELS
A. Aorta
1. Ascending aorta - from aortic valve toward right margin of sternum at R2
2. Aortic arch - behind lower half of manubrium
B. Pulmonary trunk - from pulmonary valve to point at the edge of sternum in ICS2
C. Vena cava - continuations of right border of heart just lateral to the right sternal margin
D. Right brachiocephalic vein - continuation of direction of s. vena cava from confluence at
lower edge of R1 to its formation behind the SC joint
E. Left brachiocephalic vein - from SC joint to lower margin of R1 on right
F. Great arteries – - arise in sequence from arch, must pass behind SC joints
1. Brachiocephalic a
2. Left common carotid a.
3. Left subclavian a.
IV. PARIETAL PLEURA
A. Right side - line of reflections
1. Apex - highest point over junction of medial and middle third of clavicle (3cm above
clavicle)
2. Crosses sternoclavicular joint
3. Near midline at sternal angle
4. Near midline to level of R6 - may drop slightly below the angle with xiphoid
5. Deviates to cross midclavicular line at R8
6. Crosses R10 at midaxillary line
7. Horizontal line from midaxillary point to neck of R12
8. Posterior reflection - vertical along sides of vertebral bodies
B. Left side - line of reflection - similar to right, except:
1. At level of R4 anteriorly it swings laterally to slightly beyond sternal edge
2. Descends vertically to reach R6, then to R8 in midclavicular
V. LUNGS
A. Lung margins - similar to parietal pleura in upper extent
B. Two rib levels higher than pleura in midclavicular, and midaxillary lines and at posterior
angles
C. Obvious cardiac notch on left, as far lateral as halfway between sternum and midclavicular
line
D. Oblique fissure
1. From T3 posteriorly (spine of T2)
2. Extends to 6th costal cartilage (5cm from midline)
3. This line generally follows vertebral border of scapula when the arm is raised
E. Horizontal fissure - along R4 from midline to the oblique fissure
F. Bronchopulmonary segments
1. Most can be easily derived from a knowledge of fissures, and projected to specific areas of the body wall
2. Superior lobe - both sides
a. anteriorly - apical and anterior segments have a surface projection
b. posteriorly - apical and posterior segments can be “mapped”
c. axillary approach - all three have surface projections
3. Middle lobe - right side
a. anteriorly - lateral and medial segments
b. axillary region - lateral segment
c. none projects to the back
4. Lingular segments
a. anteriorly - superior and inferior segments
b. axillary region - both segments
c. posteriorly - neither segment
5. Lower lobe
a. superior segment - only projects posteriorly
b. anteriorly - none of segments are accessible
c. posteriorly - superior, posterior basal, lateral basal
d. axillary region - lateral basal, anterior basal
e. medial basal segment - inaccessible as body wall projection
G. Trachea - midline - lower end slightly to right
1. bifurcation - at or below sternal angle, can be as much as 3cm lower (1 1/4 inches)