The bony landmarks of the thoracic wall are as follows:
1. Suprasternal notch (jugular notch): Just above the superior border of the manubrium sterni between the proximal medial ends of both clavicles is exactly where the jugular notch is found. At the level of lower border of the body of T2 vertebra is where it can be located. The trachea can be palpated in this notch.
2. Sternal angle (angle of Louis): It’s felt as a transverse ridge about 5 cm below the suprasternal notch. It indicates the angle made between the manubrium and the body of the sternum (the angle between the long axis of manubrium and body of sternum is 163 ° posteriorly and 17 ° anteriorly). It is located at the level of intervertebral disc between the T4 and T5 vertebrae. The 2nd rib articulates on the either side together with the sternum at this level. Therefore it utilized as surface landmark for counting the ribs.
3. Xiphisternal joint: It can be felt in the apex infrasternal/ subcostal angle created by the assembly of anterior end of subcostal margins. The xiphisternal joint is located at the level of the upper border of the body of T9 vertebra.
4. Costal margin: It creates the lower boundary of the thorax on every side and is composed by the cartilages of the 7th, 8th, 9th, and 10th ribs and the free ends of 11th and 12th ribs. The lowest point of costal margin is composed by the 10th rib and is located at the level of L3 vertebra.
5. Subcostal angle: It’s situated in the inferior end of the sternum between the sternal attachments of the 7th costal cartilage.
6. Thoracic vertebral spines: The first notable spine felt at the lower end of nuchal furrow (midline furrow on the rear of neck) is the spine of C7 vertebra (vertebra prominens). All the thoracic spines are counted below this level. For reference, the 3rd thoracic spine is located at the level of root of spine of scapula and 7th thoracic spine is located at the level of inferior angle of the scapula.
Soft Tissue Landmarks
- Nipple: In men, the nipple is normally situated in the 4th intercostal space about 4 in (10 cm) from the midsternal line. In females, its position changes significantly.
- Apex beat of the heart: It’s lowermost and outermost push of cardiac pulsation, that is felt in the left 5th intercostal space 3.5 in (9 cm) from the midsternal line or just medial to the midclavicular line.
Lines Of Orientation
The subsequent imaginary lines in many cases are utilized to describesurface places on the anterior and posterior chest wall.
1. Midsternal line: It runs vertically downwards in the median plane on the anterior aspect of the sternum.
2. Midclavicular line: It runs vertically downwards from the midpoint of the clavicle to the midinguinal point. It crosses the tip of the 9th costal cartilage.
3. Anterior axillary line: It runs vertically downwards from the anterior axillary fold.
4. Midaxillary line: It runs vertically downwards from the point in the axilla situated between the anterior and posterior axillary folds.
5. Posterior axillary line: It runs vertically downwards from the posterior axillary fold.
6. Scapular line: It runs vertically downwards on the posterior aspect of the chest going through the inferior angle of the scapula with arms at the sides of the body.