Hyoids

Question 1

_Digastric: Anterior _

Answer 1

Origin: Mandible (digastic fossa)

Insertion: Hyoid (body)

Intermed tendon fibrous loop

Actions: Elevate hyoid (swallowing)

Open mandible

Depress mandible hyoid bone fixed

Innervation: Myohyoid nerve (CNV3)

Question 2

_Digastric: Posterior _

Answer 2

Origin: Temporal bone (mastoid notch)

Insertion: Hyoid (body)

Intermed tendon fibrous loop

Actions: Elevate hyoid (swallowing)

Opening mandible

Depress mandible hyoid bone fixed

Innervation: Facial nerve (CN VII)

Question 3

Stylohyoid

Answer 3

Origin: Temporal bone (styloid)

Insertion: Hyoid bone via split tendon

Actions: Elevate hyoid (upward/posteriorly)

Innervation: Facial nerve (CN VII)

Question 4

Mylohyoid

Answer 4

Origin: Mandible (medial, mylohyoid line)

Insertion: Hyoid bone

Median tendon/mylohyoid

Actions: Elevate floor oral cavity

Hyoid bone forward (swallow)

Opening mandible (mastication)

Depress mandible when hyoid fixed

Innervation: Mylohyoid (CN V3)

Question 5

Geniohyoid

Answer 5

Origin: Mandible (inferior mental spine)

Insertion: Hyoid bone (directly)

Actions: Hyoid upward and anteriorly (swallow)

Depress and open mandible when hyoid fixed

Innervation: Anterior ramus CI

Hypoglossal nerve (CN XII)

Question 6

Omohyoid

Answer 6

Origin: Scapula (superior border)

Insertion: Hyoid bone

Actions: Depress and fix hyoid

Innervation: Ansa cervicalis (anterior rami C1-C3)

Question 7

Sternohyoid

Answer 7

Origin: Manubrium

SC joint (posterior surface)

Insertion: Hyoid bone

Actions: Depress and fix hyoid

Innervation: Ansa cervicalis (anterior rami C1-C3)

Question 8

Sternothyroid

Answer 8

Origin: Sternum (posterior manubrium)

Insertion: Thyroid cartilage (oblique line)

Actions: Depress and fix thyroid cartilage

Innervation: Ansa cervicalis (anterior rami C2-C3)

Question 9

Thyrohyoid

Answer 9

Origin: Thyroid cartilage (oblique line)

Insertion: Hyoid bone (body)

Actions: Depress and stabilize hyoid

Fix hyoid=elevate thyroid cartilage

Innervation: Hypoglossal CN XII (C1)

Question 10

Anterior scalene

Answer 10

Origin: Transverse process vertebrae C3-C6

Insertion: Rib 1

Actions: Fix and elevate Rib 1 inhalation

1st Rib fixed= lateral flex neck

Innervation: Anterior rami cervical spinal nerves

Question 11

_Middle scalene _

Answer 11

Origin: Transverse process atlas, C5-C6

Insertion: Rib 1

Actions: Fix and elevate Rib 1 inhalation

1st Rib fixed= lateral flexion neck

Innervation: Anterior rami cervical spine nerves

Question 12

Posterior scalene

Answer 12

Origin: Transverse process C4-C6

Insertion: Rib 2

Actions: Fix and elevate 2nd Rib

Rib fix lateral flex neck

Innervation: Anterior rami cervical spinal nerves

Question 13

Platysma

Answer 13

Origin: Skin over lower neck and upper lateral thorax

Insertion: Mandible (inferior border)

Skin over lower face and angle of mouth

Actions: Depress and wrinkle skin lower face and mouth

Tense skin of neck

Aid force depression mandible

Innervation: Facial nerve (CN VII) cervical branch

Question 14

Sternocleidomastiod

Answer 14

Origin: Sternum (manubrium)

Clavicle (medial 1/3)

Insertion: Temporal bone (mastiod process)

Occipital bone (superior nuchal line)

Actions: Unilateral= Tilt head same side

Rotate head opposite side

Bilateral= Extend head

Aid respiration when head fixed

Innervation: Accessory nerve (CN XI) –motor

Cervical plexus (C2, C3)–pain/proprioception

Question 15

Longus capitis

Answer 15

Origin: Transverse process (ant tuberbles) C3-C6

Insertion: Occipital bone (basilar part)

Actions: Flexion of head at atlanto-occipital

Innervation: Cervial plexus (C1-C3)

Question 16

Longus colli

• Vertical intermediate part*
• Superior oblique part*
• Inferior oblique part*

Answer 16

Origin: Anterior surface/tubercles vertebral bodies

C5-T3

C3-C5

T1-T3

Insertion: C2-C4

Atlas (anterior tubercles)

C5-C6 (anterior tubercles transverse process)

Actions: Unilateral= tilts amd rotates cervical spine to opposite side

Bilateral= Forward flexion of cervical spine

Innervation: Direct branch from cervical plexus C2-C6