OIAI Head and Neck

Sternocleidomastoid Origin

Medial clavicle, manubrium

Sternocleidomastoid Insertion

Mastoid process of skull

Sternocleidomastoid Action

Unilateral: contralateral head rotation, ipsilateral side bending Bilateral: cervical flexion, upper cervical extension

Sternocleidomastoid Innervation

Spinal accessory n. (XI)

Omohyoid Origin

Inferior belly: superior scapula, Superior belly: central tendon

Omohyoid Insertion

Inferior belly: Central tendon, Superior belly: Hyoid

Omohyoid Action

Inferior pull on hyolaryngeal apparatus (for swallowing and speech)

Omohyoid Innervation

Ventral rami via ansa cervicalis

Sternohyoid Origin

Manubrium and medial clavicle

Sternohyoid Insertion

Hyoid

Sternohyoid Action

Inferior pull on hyolaryngeal apparatus (for swallowing and speech)

Sternohyoid Innervation

Ventral rami via ansa cervicalis

Thyrohyoid origin

Thyroid cartilage

Thyrohyoid Insertion

Hyoid

Thyrohyoid Action

Inferior pul on hyolaryngeal apparatus (for swallowing and speech)

Thyrohyoid innervation

Ventral rami via ansa cervicalis

Sternothyroid Origin

Manubrium and 1st costal cartilage

Sternothyroid Insertion

Thyroid cartilage

Sternothyroid action

Inferior pull on hyoplaryngeal apparatus (for swallowing and speech)

Sternothyroid Innervation

Ventral rami via ansa cervicalis

Anterior scalene origin

Anterior tubercles of c3-6

Anterior scalene insertion

Scalene tubercle of 1st rib

Anterior scalene action

Lateral cervical flexion, forced inspiration

Anterior scalene innervation

Direct branches of ventral rami

Middle scalene origin

Posterior tubercles of all cervical vertebrae

Middle scalene insertion

1st rib posterior to subclavian a

Middle scalene action

Lateral cervical flexion, forced inspiration

Middle scalene innervation

Direct branches of ventral rami

Posterior scalene origin

Posterior tubercles of lower cervical vertebrae

Posterior scalene insertion

2nd rib

Posterior scalene action

Lateral cervical flexion, forced inspiration

Posterior scalene innervation

Direct branches of ventral rami

Longus capitis Origin

Anterior tubercles of cervical vertebrae

Longus capitis insertion

Occipital bone anterior to foramen magnum

Longus capitis action

Atlanto-occipital joint: Flexes head, Atlanto-axial joint: rotates head to same side

Longus capitis Innervation

Direct branches of ventral rami

Longus colli origin

Bodies of T1-3, anterior tubercles of cervical vertebrae, upper and lower cervical vertebral bodies

Longus colli insertion

Bodies of c1-c4

Longus Colli Action

Flexion of neck (bilateral), Lateral cervical flexion (unilateral)

Longus colli innervation

Direct branches of ventral rami

Rectus capitis posterior major Action

Head extension, ipsilateral rotation of head, ipsilateral lateral flexion

Rectus capitis posterior major innervation

Dorsal rami of upper cervical spine

Rectus capitis posterior minor action

Head extension, ipsilateral rotation of head, ipsilateral lateral flexion

Rectus capitis posterior minor innervation

Dorsal rami of upper cervical spine

Obliquus capitis superior action

Head extension, ipsilateral rotation of head, ipsilateral lateral flexion

Obliquus capitis inferior action

Head extension, ipsilateral rotation of head, ipsilateral lateral flexion

Obliquus capitis inferior innervation

Dorsal rami of upper cervical spine

Obliquus capitis superior innervation

Dorsal rami of upper cervical spine

Platysma origin

Skin of chest inferior to clavicle

Platysma insertion

Skin of face, superficial to mandible

Platysma action

Pulls skin of chest and face toward each other - grimace

Platysma innervation

Facial n (VII)

Digastric Origin

Anterior belly: tendon, Posterior belly: medial to mastoid

Digastric insertion

Anterior belly: posterior mandible, Posterior belly: tendon

Digastric action

Elevate hyoid and depress mandible, retract hyoid (posterior only)

Digastric Innervation

Anterior: Trigeminal n (V) Posterior: Facial (VII)

Stylohyoid origin

Temporal bone

Stylohyoid insertion

Hyoid

Stylohyoid action

Retracts hyoid

Stylohyoid Innervation

Facial n (VII)

Mylohyoid origin

Inner mandible

Mylohyoid insertion

Hyoid

Mylohyoid action

Contract to stiffen the floor of mouth to position food

Mylohyoid innervation

Trigeminal (V)

Geniohyoid origin

Inner chin

Geniohyoid insertion

Hyoid

Geniohyoid action

Elevate hyoid toward chin

Geniohyoid innervation

Hypoglossal (XII)

Masseter Origin

Deep surface of zygomatic arch

Masseter Insertion

Outer surface of mandibular ramus

Masseter Action

Jaw closer

Masseter Innervation

Trigeminal (V3)

Temporalis Origin

Cranial vault, sphenoid, and temporalis fossa

Temporalis Insertion

Coronoid process of the mandible

Temporalis Action

Jaw closer

Temporalis Innervation

Trigeminal (V3)

Medial Pterygoid Origin

Lateral pterygoid plate, maxilla

Medial pterygoid insertion

Inner mandible near angle

Medial pterygoid action

Closes jaw, protrudes chin

Medial pterygoid innervation

Trigeminal (V3)

Lateral pterygoid origin

Superior head: greater wing of the sphenoid, Inferior head: lateral pterygoid plate

Lateral Pterygoid insertion

Superior head: mandibular condyle and Articular disc, Inferior head: neck of mandible below condyle

Lateral pterygoid action

Superior head: pulls condyle anteriorly during jaw closure, Inferior head: pro traction of jaw during opening or protrusion of chin if closed

Lateral pterygoid Innervation Innervation

Trigeminal (V3)