NECK MUSCLES ACTIONS

Posterior Scalene

Unilateral contraction causes lateral flexion of the neck. Reversed muscle action causes Elevation of 2nd rib

Omohyoid

Depression of hyoid

Sternohyoid

Depression of hyoid

Thyrohyoid

Depression of hyoid and Elevation of thyroid cartilage

Sternothyroid

Depression of thyroid cartilage

Platysma

Draws up the skin of superior chest and neck, creating ridges in neck skin. Assists in drawing the lip laterally and depresses the mandible

Geniohyoid

Elevation of hyoid

Stylohyoid

Elevation of hyoid

Mylohyoid

Elevation of hyoid and depresses the mandible

Digastric

Elevation of hyoid, depression of the mandible, and retraction of the mandible.

Middle Scalene

Bilateral contraction: flexion of the neck. Unilateral contraction causes lateral flexion of the neck. Reversed muscle action causes Elevation of 1st rib

Sternocleidomastoid (SCM)

Bilateral contraction: flexion of the neck. Unilateral contraction results in Lateral flexion of neck/head and Contralateral rotation of neck/head

Longus Capitis

Bilateral contraction causes Flexion of head/neck. Unilateral contraction causes Lateral flexion of head/neck

Longus Colli

Bilateral contraction causes weak flexion of neck. Unilateral contraction causes lateral flexion and contralateral rotation of the neck.

Anterior Scalene

Bilateral contraction: flexion of the neck. Unilateral contraction causes lateral flexion and contralateral rotation of the neck. Reversed muscle action causes Elevation of 1st rib

Rectus Capitis Anterior

Flexion of head

Rectus Capitis Lateralis

Lateral flexion of head