Muscles that MOVE the neck

Question 1

Platysma

Answer 1

ORIGIN

Fascia of chest, particularly the deep fascia over pectoralis major muscles.

INSERTION

Mandible and angle of mouth.

ACTION

Depresses skin of lower mouth and mandible (as in expressions of sadness and fright). Draws the skin of the neck superiorly when teeth are clenched.

INNERVATION

Facial nerve (CN VII).

Question 2

Sternocleidomastoid

Answer 2

ORIGIN

Manubrium of the sternum and medial 1/3 of clavicle.

INSERTION

Mastoid process of the temporal bone, superior nuchal line of occipital bone.

ACTION

Bilateral contraction: Extension of the head and flexion of the neck. Unilateral contraction: Ipsilateral cervical lateral flexion and contralateral rotation of the head.

INNERVATION

Spinal accessory nerve C2, C3.

Question 3

Rectus Capitis Anterior

Answer 3

ORIGIN

Transverse process of C1 (Atlas).

INSERTION

Inferior surface of occipital bone.

ACTION

Flexion of neck at atlanto-occipital joint.

INNERVATION

C1-C2 spinal nerves.

Question 4

Scalene Muscles (Anterior, Medius, Posterior)

*Middle scalene shown in photo.

Answer 4

ORIGIN

Transverse processes of C2-C7.

INSERTION

First and second ribs.

ACTION

Elevates first and second ribs, flexes the cervical spine (anterior), rotates head to opposite sides, and laterally flexes the cervical spine.

INNERVATION

Cervical.

Question 5

Splenius Capitis

Answer 5

ORIGIN

Nuchal ligament and spinous processes of C7-T3. INSERTION

Mastoid process of temporal bone and occipital bone.

ACTION

Unilateral contraction produces ipsilateral lateral flexion of the head and neck and ipsilateral rotation of the head. Bilateral contraction produces extension of the head and neck.

INNERVATION

Spinal.