7. The transversus ([p. 155], and [Fig. 69], l). Requires no further dissection.
8. The rectus abdominis ([p. 155], and [Fig. 73], k). Open its sheath by a longitudinal incision near the linea alba.
9. The external intercostals ([p. 150], and [Fig. 73], m; [Fig. 69], i). To see these, remove the origins of the levator scapulæ and serratus anterior; also the serratus posterior superior.
10. The internal intercostals ([p. 151], and [Fig. 69], k). To uncover these, remove the external intercostals from between two or three pairs of ribs.
11. The transversus thoracis ([p. 151]). To see this muscle, which lies on the inner surface of the thoracic wall, it is necessary to cut through the ribs on one side one or two inches from the sternum, and open the thorax. The muscle can then be observed directly.
(The levatores costarum will be dissected later.)
VI. Muscles on the Ventral Side of the Vertebral Column in the Neck Region ([Fig. 72]).
Clean the surface of these muscles, removing pharynx, larynx, œsophagus, and trachea, if this has not been done.