Chapter II: SUPERFICIAL MUSCLES OF THE FACE AND HEAD (pp. 96-107, and Figs. 63

and 64).

These will perhaps not usually be dissected by the student. They should be studied on a well-dissected laboratory preparation, if possible. If they are to be dissected, this should be done if possible on a fresh specimen, as it is very difficult to dissect them on preserved material. Proceed as follows:

The skin should be removed with care from the sides and top of the face and head, without injury to the external ear.

1. The platysma (p. 95, and Fig. 62, _a_). Determine its cranial attachments.

2. The intermedius scutulorum (p. 96, and Fig. 63, _a_).

3. The corrugator supercilii medialis (Fig. 63, _b_).

4. The orbicularis oculi (Fig. 63, _c_; Fig. 64, _s_).

5. The corrugator supercilii lateralis (Fig. 64, _k_).

6. Notice the frontoauricularis if it exists.

7. The levator auris longus (Fig. 63, _g_, _g′_). Transect and reflect.

8. The auricularis superior (Fig. 63, _k_). Transect.

9. The abductor auris longus (Fig. 63, _m_). Transect.

10. The abductor auris brevis (Fig. 63, _l_). Transect.

11. The epicranius (Fig. 63, _h_, _h′_). In dissecting this muscle the intermedius scutulorum and corrugator supercilii medialis may be cut by an incision parallel to the middle line but a short distance to one side of it.

12. The zygomaticus (Fig. 64, _d_). This and the two following muscles may usually be best seen running beneath the fibres of the platysma, without reflecting the latter. If necessary, however, the platysma may be transected and reflected, though this can be done only with great difficulty.

13. The submentalis (Fig. 64, _c_).

14. The depressor conchæ (Fig. 64, _b_).

The zygomaticus, submentalis, and depressor conchæ should now be transected one or two centimeters from the external ear. The corrugatores supercilii lateralis and medialis may be cut across between the eye and the ear, and reflected. There is thus exposed:

15. The frontoscutularis. Transect near the scutiform cartilage.

16. The adductor auris inferior (Fig. 64, _o_). Transect near its insertion.

The external ear is now attached to the head only by the external auditory meatus and the tragicus lateralis muscle. Read the description of the latter (p. 418, and Fig. 67, _a_), find it beneath the fat which surrounds the proximal portion of the external ear, and cut it as far ventrad as possible. Now cut across the cartilaginous auditory meatus as near to the tympanic bone as possible, and remove the external ear, preserving it for future study. (The remainder of the muscles of the external ear may be studied in connection with the study of the auditory organ.)

17. The orbicularis oris (p. 105 and Fig. 64, _i_).

18. The zygomaticus minor, if it exists (p. 105, and Fig. 64, _e_).

19. The quadratus labii superioris (p. 105).

_a._ The levator labii superioris proprius (Fig. 64, _f_).

_b._ The levator labii superioris alæque nasi (Fig. 64, _g_).

20. The caninus (p. 106, and Fig. 64, _f′_).

21. The buccinator (p. 106).

22. The myrtiformis (p. 106, and Fig. 64, _h_).

23. The “moustachier” (p. 107).

24. The quadratus labii inferioris (p. 107).