I'm going to show you how to find vertical lines.
Anterior lines of the chest
1. Anterior midline (midsternal)
- to find Jugular notch (the deepest point of the sternal incision, between clavicles)
- to find xiphoid process (you feel it with your fingers in the end of the sternum)
Then connect these two points to form the midsternal line.
2. Sternal line
- lateral side of the sternum (the junction of ribs and sternum)
3. Midclavicular line
- to find the center of the clavicle. The midclavicular line runs downward from this point.
To make it easier: elevate the shoulder. Then the clavicle is more visible.
- between the midclavicular and sternal lines.
Lateral lines of the chest
- to elevate the arm when determining the lines
5. Anterior axillary line
- it runs downward from lateral border of pectoralis major muscle (along the anterior axial fold, close to the front of the thorax)
6. Posterior axillary line
- it runs downward from lateral border of latissimus dorsi muscle (along the posterior axillary fold, close to the back)
7. Middle axillary line (Midaxillary line)
- the axilla has a shape of triangle. The line runs downward from the center of this area (the deepest point).
- other method: the midaxillary line runs between the posterior and anterior axillary lines, from the deepest point.
Posterior lines of the chest
8. Scapular line
- projected to the inferior scapular angle
To make it easier: put your hand on the back and bend your arm - then the scapula is more visible.
9. Posterior median line
- projected to the spinous processes of vertebra
10. Vertebral line
- projected to the transverse processes of vertebra
11. Paravertebral line
- between the vertebral and scapular lines
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That's all. Any other ideas?
P.S. These pictures were found on the web. I just added a few amendments to them.