Neck Muscles

Question 0

Platysma

Answer 0

Origin: inferior border of the mandible, skin, and subcutaneous tissue of the lower face

Insertion: fascia covering superior surface of the pec major and deltoid muscles

Innervation: cervical branch of facial nerve (CN VII)

Action: draw corners of the mouth inferiorly and draw skin of neck superiorly when teeth are clenched

Question 1

Sternocleidomastoid

Answer 1

Origin: lateral surface of the mastoid process and lateral half of the superior nuchal line

Insertion: clavicular head - superior surface of medial third of the clavicle and sternal head - anterior surface of the manubrium

Innervation: spinal accessory nerve (CN XI) and C2,C3

Action: bilaterally extend the head at atlanto-occipital joint and protrusion and unilaterally lateral flexion to the same side and rotation to the opposite side so that the face is turned superiorly