Dissection of breast and anterolateral thoracic wall

Seventh intercostal space.

For permissions information regarding the use of these images, please contact Drew Bourn at dbourn@stanford.edu

Image #115-7
Bassett ImageDiagram Image
Legend Image
Dissection of breast and anterolateral thoracic wall
Seventh intercostal space.
The ribs above the eighth on the left side have been cut off along the mid-axillary line. The intercostal muscles of the seventh space have been retained and have been separated into their three layers (17, 18, 19). The middle layer, the internal intercostal muscle, becomes membranous in its posterior portion. The transition from muscle to membrane occurs just anterior to the cut end of the seventh rib (16). The membrane has been incompletely preserved in the seventh interspace. In the sixth interspace the membrane is clearly visible (14). The intercostal vessels and nerve have been separated slightly.
1 . Rib VIII
2 . Costal groove VII
3 . Posterior intercostal vein
4 . Posterior intercostal artery (a piece of this vessel several cms. in length has been removed laterally)
5 . Intercostal nerve VII
6 . Endothoracic fascia
7 . Costal pleura
8 . Diaphragm
9 . Posterior intercostal vein VI (cut off)
10 . Posterior intercostal artery VI (cut off)
11 . Intercostal nerve VI (cut off)
12 . Costal pleura
13 . Innermost intercostal muscle
14 . Internal intercostal membrane
15 . External intercostal muscle
16 . Rib VII (cut off)
17 . External intercostal muscle (reflected laterally)
18 . Innermost intercostal muscle (reflected inward)
19 . Internal intercostal muscle
20 . Muscular branch of intercostal nerve
21 . Lateral cutaneous branch intercostal nerve VII