Muscles of the Neck

Question 1

Platysma

Answer 1

ORIGIN: inferior border of mandible and parotid fascia
INSERTION: pectoral fascia overlaying pec. maj. and deltoid muscles
ACTION: depression of ankles of mouth and mandible, draws skin of neck superiorly when teeth are clenched
INNERVATION: CNVII (facial nerve)

Question 2

Sternocleidomastoid

Answer 2

ORIGIN:
sternal head - anterior surface of the manubrium
clavicular head - medial 3rd of clavicle
INSERTION: mastoid process, lateral part of superior nuchal line of occipital bone
ACTION: lateral flexion of head and neck (ipsilateral), rotation of head (contralateral)
INNERVATION: CNXI (accessory nerve)

Question 3

Digastric

Answer 3

ORIGIN:
anterior belly - digastric fossa of mandible
posterior belly - mastoid notch of temporal bone
INSERTION: hyoid bone
ACTION: elevation of hyoid bone, depression of mandible
INNERVATION:
anterior belly - CNV (trigeminal nerve)
posterior belly - CNVII (facial nerve)

Question 4

Mylohyoid

Answer 4

ORIGIN: mylohyoid line of mandible
INSERTION: body of hyoid bone, mylohyoid raphe
ACTION: elevation and protrusion of hyoid bone, elevation of tongue, depression of mandible
INNERVATION: CNV (trigeminal nerve)

Question 5

Geniohyoid

Answer 5

ORIGIN: inferior mental spine of mandible
INSERTION: body of hyoid
ACTION: elevation of hyoid bone, depression of mandible
INNERVATION: communicating branch of C1 spinal nerve via CNXII (hypoglossal nerve)

Question 6

Stylohyoid

Answer 6

ORIGIN: styloid process of temporal bone
INSERTION: body of hyoid
ACTION: elevation nad retraction of hyoid bone, lowers mandible
INNERVATION: CNVII (facial nerve)

Question 7

Omohyoid

Answer 7

ORIGIN: superior body of scapular near suprascapular notch
INSERTION: inferior border of hyoid
ACTION: depression and stabilisation of hyoid bone and larynx for phonation and swallowing
INNERVATION: anterior rami of cervical spinal nerves

Question 8

Sternothyroid

Answer 8

ORIGIN: posterior surface of manubrium of sternum, costal cartilage of rib 1
INSERTION: oblique line of thyroid cartilage
ACTION: depression and stabilisation of larynx (thyroid cartilage) for phonation and swallowing
INNERVATION: anterior rami of cervical spinal nerves

Question 9

Thyrohyoid

Answer 9

ORIGIN: oblique line of thyroid cartilage
INSERTION: lower border of hyoid bone
ACTION: depression and stabilisation of hyoid bone, elevation of larynx during swallowing
INNERVATION: anterior rami of C1 via CNXII (hypoglossal nerve)

Question 10

Longus capitis

Answer 10

ORIGIN: inferior surface of basilar part of occipital bone
INSERTION: anterior tubercles of transverse processes of 3-5 cervical vertebrae
ACTION: flexion of head
INNERVATION: anterior rami of cervical spinal nerves

Question 11

Longus colli

Answer 11

ORIGIN:
superior part - anterior tubercles of transverse processes C3-C5
vertical part - anterior surfaces of bodies of T1-T3 and C5-C7
inferior part - anterior surfaces of bodies of T1-T3
INSERTION:
superior part - tubercle of anterior arch of atlas
vertical part - anterior surface of bodies of C1-C3
inferior part - anterior tubercles of transverse processes of C3-C6
ACTION:
unilateral - rotation of neck (contralateral), lateral flexion of neck (ipsilateral)
bilateral - flexion of neck
INNERVATION: anterior rami of cervical spinal nerves

Question 12

Rectus capitis anterior

Answer 12

ORIGIN: anterior surface of lateral mass and transverse process of atlas
INSERTION: interior surface of basilar part of occipital bone
ACTION: flexion of head
INNERVATION: anterior rami of cervical spinal nerves

Question 13

Rectus capitis lateralis

Answer 13

ORIGIN: inferior surface of jugular process of occipital bone
INSERTION: superior surface of transverse process of atlas
ACTION: lateral flexion of head (ipsilateral)
INNERVATION: anterior rami of cervical spinal nerves

Question 14

Scalene anterior

Answer 14

ORIGIN: anterior tubercles of transverse processes of C3-C6, muscle lays btw subclavian vein and artery and the roots of the brachial plexus pass posterior to it, the phrenic nerve crossing its anterior surface
INSERTION: scalene tubercles at 1st rib
ACTION:
unilateral - elevation of 1st rib during forced inspiration, lateral flexion of neck (ipsilateral)
bilateral - flexion of neck
INNERVATION: anterior rami of cervical spinal nerves

Question 15

Scalene medius

Answer 15

ORIGIN: posterior tubercles of transverse processes of C2-C7
INSERTION: upper surface of 1st rib behind subclavian artery
ACTION: elevation of 1st rib during forced inspiration, lateral flexion of neck (ipsilateral)
INNERVATION: anterior rami of cervical spinal nerves

Question 16

Scalene posterior

Answer 16

ORIGIN: posterior tubercles of transverse processes of C4-C6
INSERTION: external border of 2nd rib
ACTION: elevation of 2nd rib, lateral flexion of neck (ipsilateral)
INNERVATION: anterior rami of cervical nerves

Question 17

Rectus capitis posterior major

Answer 17

ORIGIN: spinous process of axis (C2)
INSERTION: lateral part of occipital bone below inferior nuchal line
ACTION:
unilateral - rotation of head (ipsilateral)
bilateral - extension of head
INNERVATION: suboccipital nerve

Question 18

Rectus capitis posterior minor

Answer 18

ORIGIN: posterior tubercles of atlas (C1)
INSERTION: medial part of inferior nuchal line
ACTION: extension of head
INNERVATION: suboccipital nerve

Question 19

Obliquus capitis inferior

Answer 19

ORIGIN: spinous process of axis (C2)
INSERTION: transverse process of atlas (C1)
ACTION:
unilateral - rotation of head (ipsilateral)
bilateral - extension of head
INNERVATION: suboccipital nerve, 1st and 2nd cervical nerves

Question 20

Obliquus capitis superior

Answer 20

ORIGIN: transverse process of atlas (C1)
INSERTION: occipital bone below superior nuchal line
ACTION:
unilateral - lateral flexion of head (ipsilateral)
bilateral - extension of head
INNERVATION: suboccipital nerve, 1st and 2nd cervical nerves