Neck Muscles

Question 0

Geniohyoid

Answer 0

O: inner surface of anterior part of mandible on each side of midline (inferior mental spines)
I: hyoid bone
A: pulls hyoid bone upward and anteriorly; depresses mandible when hyoid bone is fixed
Inn: branch from anterior rami of C1(hypoglossal)

Question 1

Mylohyoid

Answer 1

O: medial surface of mandible (mylohyoid line)
I: hyoid bone; along midline with muscle of other side
A: elevates floor of oral cavity; depresses mandible when hyoid bone is fixed
Inn: trigeminal n (mandibular division)

Question 2

Digastric

Answer 2

O: medial to mastoid process (digastric notch)
I: inner surface of mandible adjacent to midline (digastric fossa); intermediate tendon held to hyoid bone by fascia
A: pulls hyoid bone upward and anteriorly; depresses mandible when hyoid bone is fixed
Inn: anterior belly: trigeminal N (mandibular division); posterior belly: facial N

Question 3

Stylohyoid

Answer 3

O: styloid process
I: hyoid bone
A: pulls hyoid bone upward and posteriorly
Inn: facial N

Question 4

Sternocleidomastoid

Answer 4

O: sternum and medial third of clavicle
I: mastoid process of temporal bone
A: both muscle: flexion of head and neck; one muscle: lateral flexion (turn face to opposite side)
Inn: accessory N (motor); spinal nerves C2 and C3 (sensory)

Question 5

Sternohyoid

Answer 5

O: sternum (posterior)
I: hyoid bone
A: depression and/or fixation of hyoid bone
Inn: anterior rami of first three cervical spinal nerves through ansa cervicalis

Question 6

Sternothyroid

Answer 6

O: sternum (posterior surface)
I: thyroid cartilage
A: depression and/or fixation of thyroid cartilage
Inn: anterior rami of first three cervical spinal nerves through ansa cervicalis

Question 7

Thyrohyoid

Answer 7

O: thyroid cartilage
I: hyoid bone
A: depression and/or stabilization of hyoid bone; if hyoid bone is fixed, elevation or thyroid cartilage
Inn: anterior ramus of C1 by way of hypoglossal nerve

Question 8

Omohyoid

Answer 8

O: superior border if scapula
I: hyoid bone
A: depression and/or fixation of hyoid bone
Inn: anterior rami of first three cervical spinal nerves through ansa cervicalis

Question 9

Anterior scalene

Answer 9

O: transverse processes of C3-C6
I: first rib
A: fixation or elevation of first rib during inhalation. With rib fixed: lateral flexion of neck
Inn: anterior rami of cervical spinal nerves at origin of muscle

Question 10

Middle scalene

Answer 10

O: transverse processes of lower C3-C7 cervical vertebrae (possibly C2)
I: first rib
A: fixation or elevation of first rib during inhalation. With rib fixed: lateral flexion of neck
Inn: anterior rami of cervical spinal nerves at origin of muscle

Question 11

Posterior scalene

Answer 11

O: transverse processes of C4-C6
I: second rib
A: fixation or elevation of second rib; with rib fixed: lateral flexion of neck
Inn: anterior rami of cervical spinal nerves at origin of muscle