In the middle of the surface of the chest anteriorly there are three regions: 1. The suprasternal region is the part above the sternum between the sterno-mastoid muscles. It is the suprasternal notch.

2. The upper sternal region extends from the suprasternal notch to a line drawn opposite the third costal cartilages.

3. The lower sternal region is behind the second piece of the sternum from the third costal cartilages down.

Anteriorly on the chest there are four regions (Fig. 212):

1. The supraclavicular region, above the clavicle. This includes the supraclavicular fossa.

2. The infraclavicular region, below the clavicle down to the upper edge of the third rib.

3. The mammary region, from the upper edge of the third to the upper margin of the sixth rib. This extends from the edge of the sternum to the anterior axillary fold and has the nipple nearly in its centre.

Fig. 212.   The anterior regions of the chest.

Fig. 212. - The anterior regions of the chest.

4. The inframammary region extends from the upper margin of the sixth rib to the lower margin of the thorax.

Laterally on the chest between the folds of the axilla there are two regions:

1. The upper axillary region extends down to the upper border of the sixth rib.

2. The lower axillary region extends from the upper border of the sixth rib to the lower edge of the thorax.

Posteriorly there are four scapular regions (Fig. 213):

1. The suprascapular region is above the spine of the scapula.

2. The scapular region is the part covered by the body of the scapula below its spine.

3. The infrascapular region is the part of the chest below the scapula between its angle and the lower edge of the chest.

4. The interscapular region is the part between the posterior edge of the scapula and the median line.