IV. Muscles of the Neck and the Deep Muscles of the Head.
If the superficial muscles of the head have been dissected according to the directions above given ([p. 434]), the skin of the head and neck, and the external ear, will have been removed, and the specimen is ready for further study. The parotid and submaxillary glands ([Fig. 65], 1 and 2) should be removed if this has not been done; also the lymphatic glands ([Fig. 65], 3).
If the superficial muscles of the head have not been dissected and are not to be, remove the skin from the side of the neck, head, and face to the median dorsal line, removing the thin superficial muscles with the skin. Remove also the parotid, submaxillary, and lymphatic glands ([Fig. 65], 1, 2, and 3), and cut through the ear-muscles and the cartilaginous auditory meatus (under direction) and remove the external ear. Clean fat, connective tissue, etc., from the surface of the muscles of the thorax, neck, and head; then dissect as follows:
1. The sternomastoid ([p. 139], and [Fig. 65], g). Transect and reflect it.
2. The cleidomastoid ([p. 120], and [Fig. 65], h). This has already been transected; examine now its origin.
Remove the large lymphatic gland beneath the sternomastoid and close to the tympanic bulla, and clean the surface of the muscles in this region.
3. The levator scapulæ ventralis ([p. 120], and [Fig. 72], c, c′, c″). This has already been cut; study now its origin.
4. The sternohyoid ([p. 140], and [Fig. 65], e). In raising it begin at the cranial end and take care not to injure the subjacent sternothyroid ([Fig. 65], g′). Transect.
5. The sternothyroid ([p. 141], and [Fig. 65], g′). Transect.