Block 3 neck muscles

Platysma

O: Subcutaneous layer of upper thorax | I: Mandible | N: Facial n. | A: Mastication, facial expression?

Sternohyoid “progenitor”

O: Manubrium + medial end of clavicle | I: Body of hyoid | N: Ansa cervicalis (C1, C2, C3) | A: Depresses hyoid after food is swallowed

Sternothyroid

O: posterior manubrium | I: oblique line on lamina of thyroid cartilage | N: Ansa cervicalis (C1, C2, C3) | infrahyoid

Thyrohyoid

O: Oblique line of lamina of thyroid cartilage | I: Inferior border of greater cornua of hyoid bone | N: C1 spinal n. via hypoglossal | infrahyoid but elevates larynx

Omohyoid

O: (Inferior) superior border of scapula, medial to scapular notch | I: Inferior border at body of hyoid (superior) | N: Ansa cervicalis (C1, C2, C3) | infrahyoid

Digastric

O: Digastric fossa inferior internal border of mandible (Ant. belly) / Mastoid notch medial to mastoid process (Post. belly) | I: Intermediate tendon attaches the two to hyoid bone | N: (Ant.) n. to mylohyoid via V3, mandibular / (Post.) Facial n. | suprahyoid

Stylohyoid

O: Posterolateral styloid process | I: Body of hyoid (sometimes splits around digastric) | N: Facial n. | suprahyoid, but no mandible depression

Mylohyoid

O: Mylohyoid line of mandible | I: Body of hyoid (post.) / median raphe (middle / ant.) | N: n. to mylohyoid via V3, mandibular | suprahyoid, raise floor of mouth when swallowing

Geniohyoid

O: Inferior mental spine of mandible | I: Ant. body of hyoid | N: 1st cervical n. via hypoglossal n. | suprahyoid

Scalenus Anterior

O: Transverse of C3-C6 (4 tendons) | I: Scalene tubercle of 1st rib | N: Ventral rami of C4, C5, C6 | A: Elevates 1st rib when neck fixed, flexes neck, lateral rotation opp.

Scalenus Medius

O: Transverse of C2-C7 (maybe atlas) | I: Post. to groove for subclavian a. on 1st rib (ant.) | N: Ventral rami of C3-C8 spinal n. | A: Elevates 1st rib when neck fixed, flexes neck, lateral rotation opp.

Scalenus Posterior

O: Transverse of C4-C6 | I: Anterior surface of 2nd rib | N: Ventral rami of C6-C8 | A: Elevates 1st rib when neck fixed, flexes neck, lateral rotation opp, AND Helps elevate 2nd rib

Longus Colli

O: Bodies of T1-T3, Transverse of C5-C3 | I: Transverse of C6-C3, Anterior tubercle of C1 | N: Ventral rami of C2-C6 | A: Neck flexion, opp. rotation

Longus Capitis

O: Anterior tubercles of C6-C3 transverse | I: Basilar occipital bone | N: Ventral rami of C1-C3 | A: Flexes head @ C0-C1

Rectus Capitis Anterior

O: Anterior surface and lateral mass of C1 | I: Base of skull ant. to occipital condyle | N: C1-C2 branches of loop | A: Flexes head @ C0-C1

Rectus Capitis Lateralis

O: Transverse C1 | I: Jugular process of occiput | N: C1-C2 branches of loop | A: Flexes head; stabilize sidebending?

Sternocleidomastoid (2H)

O: manubrium, clavicle I: mastoid process N: CN XI A: lateral flex same side, oppo rotation, bilateral flex neck, ext. head