H and N 1.6

Question 1

What do the muscles of the larynx act on?

Answer 1

• The muscles of the larynx are small

- They act on the laryngeal cartilages

Question 2

What forms the vocal ligament?

Answer 2

The most superior portion of the conus elasticus is thickened and forms the vocal ligament

Question 3

What do the vocal folds contain?

Answer 3

The vocal folds themselves contain a small amount of muscle called the vocalis muscle, which is derived from some of the fibers of the thyroarytenoid muscle

Question 4

What are all the intrinsic muscles innervated by?

Answer 4

1. With the exception of the cricothyroid, all the intrinsic muscles of the larynx are innervated by the recurrent laryngeal nerve of the vagus
2. All of these muscles are derived embryologically from the 4th through 6th pharyngeal (branchial) arches.

Question 5

What is the origin of the scalenus anterior?

Answer 5

The scalenus anterior arises from the anterior tubercles of the transverse processes of C3-C6 vertebrae

Question 6

What is the origin of the scalenus medius and posterior?

Answer 6

The scalenus medius and scalenus posterior arise from the posterior tubercles of the transverse processes of C2-C7 (middle) and C4-C6 (posterior)

Question 7

What is inferior attachment of the scalenus anterior?

Answer 7

The scalenus anterior attaches to the scalene tubercle of the 1st rib

Question 8

What is inferior attachment of the scalenus medius?

Answer 8

The scalenus medius attaches to the superior surface of the 1st rib

Question 9

What is inferior attachment of the scalenus posterior?

Answer 9

he scalenus posterior attaches to the external border of the 2nd rib

Question 10

What is the action of the scalenus?

Answer 10

1. The scalenus anterior and scalenus medius elevate the 1st rib
2. When that rib is fixed, they also flex the neck forward and laterally and rotate it to the opposite side
3. The scalenus posterior raises the 2nd rib and flexes and slightly rotates the neck

Question 11

What are the innervation of the scalenus?

Answer 11

1. The scalenus anterior is innervated by C5-C7 anterior rami
2. the scalenus medius, by C3-C8 anterior rami
3. the scalenus posterior, by anterior rami of C6-C8

Question 12

What are the lateral vertebral muscles?

Answer 12

1. The scalenus muscles are often called lateral vertebral muscles
2. They form a large portion of the floor of the posterior cervical triangle
3. Components of the brachial plexus can be seen emerging between the scalenus anterior and scalenus medius muscles

Question 13

How are scalenus muscles used in respiration?

Answer 13

-The scalenus muscles are accessory muscles of respiration and help elevate the first 2 ribs during deep or labored breathing.

Question 14

What do the scalenus muscles form?

Answer 14

-They form a portion of the floor of the posterior cervical triangle and are crossed by the accessory nerve (CN XI) as it passes between the sternocleidomastoid and trapezius muscles.

Question 15

Where. is the phrenic nerve with the scalenus muscles?

Answer 15

1. The phrenic nerve (C3-C5) is observed on the anterior surface of the scalenus anterior muscle; it courses inferiorly toward the diaphragm, which it innervates.
2. Trauma to the neck can damage these nerves.

Question 16

Where does the longus capitis arise from?

Answer 16

The longus capitis arises from the anterior tubercles of the C3-C6 vertebral transverse processes

Question 17

Where does the longus Colli arise from?

Answer 17

The longus colli arises from the bodies of the T1-T3 vertebrae, the bodies of the C4-C7 vertebrae, and transverse processes of the C3-C6 vertebrae.

Question 18

Where does the longus’ attach?

Answer 18

1. The longus capitis attaches to the basilar portion of the occipital bone
2. The colli portion attaches to the anterior tubercle of the atlas (C1), the bodies of the C2-C4 vertebrae, and transverse processes of the C5-C6 vertebrae

Question 19

What is the action of the longus’?

Answer 19

1. Both muscles flex the neck, although the longus colli is weak
2. The longus colli also slightly rotates and laterally bends the neck

Question 20

What is the longus capitis innervated by?

Answer 20

The longus capitis is supplied by the C1-C3 anterior rami

Question 21

What is the longus Colli innervated by?

Answer 21

The longus colli is supplied by the C2-C6 anterior rami

Question 22

Where doe the longus’ lie?

Answer 22

• The longus capitis and longus colli lie in front of the cervical vertebrae and are often called prevertebral muscles
• They help other muscles flex the cervical spine.

Question 23

What do the longus’ and scalenus form?

Answer 23

1. These muscles and the scalenus muscles comprise anterior muscle groups often lumped together as “prevertebral” muscles
2. They are encased in a strong fascial sleeve called the prevertebral fascia and do not tolerate swelling well because of this tight enclosure

Question 24

Where is the retropharyngeal space lie?

Answer 24

-Just anterior to the prevertebral fascia, where it covers the bodies of the cervical vertebrae, lies the retropharyngeal space (this space is posterior to the buccopharyngeal fascia [the posterior portion of the pretracheal fascia] covering the posterior pharynx and esophagus)

Question 25

Where can infections in this vertical space lie?

Answer 25

Infections in this vertical space may pass superiorly to the base of the skull or inferiorly into the posterior mediastinum of the thorax