Neck muscle: OIA

Platysma

Origin - Fascia of pectoralis major and deltoid. Insertion - base of mandible and surrounding fascia. Action - Tenses skin of neck, draws down lower lip and angle of mouth, helps depress mandible.

Sternocleidomastoid

Origin - Manubrium of sternum, medial clavicle. Insertion - Mastoid process of temporal bone. Action - Bends neck laterally and rotates head to opposite side, both heads together flex the neck.

Digastric

Origin - Posterior belly: temporal bone Anterior belly: mandible. Insertion - Hyoid bone. Action - steady hyoid during swallowing and speaking, helps to open mouth and depress mandible.

Rectus Capitis Posterior Minor

Origin - Posterior tubercle of atlas. Insertion - Occiput. Action - Extends the head. *Suboccipital Muscles

Rectus Capitis Posterior Major

Origin - Spinous process of axis. Insertion - Occiput. Action - Extends the head, rotates it towards the same side. *Suboccipital Muscle

Obliquus Capitis Inferior

Origin - Spinous process of axis. Insertion - Transverse process of atlas. Action - Rotates head. *Suboccipital Muscles

Scalene Posterior

Origin - Transverse process cervical vertebrae 4-6. Insertion - 2nd rib. Action - Flexes neck anterior and laterally, rotation of neck to opposite side, raises 2nd rib. *accessory muscles of inspiration*

Rectus Capitis Anterior

Origin - Transverse process of atlas. Insertion - Occiput anterior to foramen magnum. Action - Flexes head. *helps stabilize neck while coughing and sneezing

Rectus Capitis Lateralis

Origin - Transverse process of atlas. Insertion - Occiput bone. Action - Bends head laterally. * Helps stabilize neck while coughing or sneezing

Obliquus Capitis Superior

Origin - Transverse process of atlas. Insertion - Occiput. Action - Extends the head. *Suboccipital Muscles

Scalene Medius

Origin - Transverse process of cervical vertebrae 2-7. Insertion - 1st rib. Action - Flexes neck anterior and laterally, rotation of neck to opposite side, raises the first rib. *accessory muscles of inspiration*

Scalene Anterior

Origin - Transverse process of cervical vertebrae 3-6. Insertion - 1st rib. Action - Flexes neck anterior and laterally, rotation of neck to opposite side, raises the first rib. *accessory muscles of inspiration*

Longus Colli

Origin - Transverse processes of cervical vertebrae 3-5, lower cervical/upper thoracic. Insertion - Anterior arch of atlas, anterior bodies of cervical vertebrae 3-5, transverse processes cervical vertebrae 5-6. Action - Flexes the neck.

Longus Capitis

Origin - Transverse processes of cervical vertebrae 3-6. Insertion - Occiput anterior to foramen magnum. Action - Flexes cervical vertebrae, laterally flex the head.