Muscles of Facial Expression & of Mastication
The muscles of the skull and face are divided into two groups. The muscles of facial expression make up the superficial muscle layer in the face. The muscles of mastication are responsible for the movement of the mandible during mastication (chewing).
Fig. 30.1 Muscles of facial expression
Fig. 30.2 Muscles of mastication
Left lateral view.
Muscle Origins & Insertions on the Skull
Fig. 30.3 Lateral skull: Origins and insertions
Left lateral view. Muscle origins (red), insertions (blue). Note: There are generally no bony insertions for the muscles of facial expression. These muscles insert into skin and other muscles of facial expression.
Fig. 30.4 Mandible: Origins and insertions
Medial view of right hemimandible (inner surface). Muscle origins (red), insertions (blue).
Fig. 30.5 Skull base: Origins and insertions
Inferior view of external skull. Muscle origins (red), insertions (blue).
Fig. 30.6 Hyoid bone: Origins and insertions
Muscle origins (red), insertions (blue).
Muscle Facts (I)
The muscles of facial expression originate on bone and/or fascia, and insert into the subcutaneous tissue of the face. This allows them to produce their effects by pulling on the skin.
Fig. 30.7 Occipitofrontalis
Anterior view.
Fig. 30.8 Muscles of the palpebral fissure and nose
Anterior view.
Fig. 30.9 Muscles of the ear
Left lateral view.
Fig. 30.10 Muscles of the mouth
Left lateral view.
Muscle Facts (II)
The muscles of mastication are located at various depths in the parotid and infratemporal regions of the face. They attach to the mandible and receive their motor innervation from the mandibular division of the trigeminal nerve (CN V3). The muscles of the oral floor that aid in opening the mouth are found on p. 562.
Fig. 30.11 Masseter muscle
Left lateral view.
Fig. 30.12 Temporalis muscle
Left lateral view.
Fig. 30.13 Lateral pterygoid muscle
Left lateral view.
Fig. 30.14 Medial pterygoid muscle
Left lateral view.
Fig. 30.15 Masticatory muscle sling
Oblique posterior view.
