Muscular System Activity 1
- Risorius
Origin: Fascia over the salivary gland
Insertion: Skin at the angle of the mouth
Action: Draw the angle of the mouth laterally - Platysma
Origin: Fascia over the deltoid and pectoralis major
Insertion: Mandible, blends with the muscles around the angle of the mouth, and the skin of lower face
Action: Draw the outer part of the lower lip inferiorly and posteriorly, and depress the mandible - Buccinator
Origin: Alveolar processes of the maxilla and the mandible and pterygomandibular raphe
Insertion: Orbicularis oris
Action: Press the cheeks against the teeth and the lips, draw the corners of the mouth laterally, and assist in mastication by keeping the food between the teeth - Frontal belly of the occipitofrontalis
Origin: Epicranial aponeurosis
Insertion: Skin superior to the supraorbital margin
Action: Draw the scalp anteriorly, raise the eyebrows, and wrinkle the skin of the forehead horizontally - Orbicularis oculi
Origin: Medial wall of the orbit
Insertion: Circular path around the orbit
Action: Close the eye - Corrugator supercilli
Origin: Medial end of the superciliary arch of the frontal bone
Insertion: Skin of the eyebrow
Action: Draw the eyebrow inferiorly and wrinkle the skin of the forehead vertically