Superficial Structures of the Neck 3

Question 1

Where do strap muscles get their nerve supply from?

Answer 1

From the upper cervical ventral rami.

Question 2

Which upper cervical ventral rami hitch hike along the hypoglossal nerve?

Answer 2

The ones from C1.

Question 3

What do fibres from C1 leave the hypoglossal nerve as?

Answer 3

They leave the nerve as the superior root of the ansa cervicalis.

Question 4

What do the other upper cervical ventral rami form?

Answer 4

They form the inferior root of the ansa cervicalis.

Question 5

When do the superior and inferiro root of the ansa cervicalis join?

Answer 5

They join as a U shaped loop on the common carotid artery and the internal jugular vein.

Question 6

Where do branches of the ansa enter?

Answer 6

They enter the strap muscles.

Question 7

Describe how a nerve containing only C1 fibres works independently of the ansa for the strap like muscle.

Answer 7

A small nerve containing only C1 fibres leaves the hypoglossal nerve separately and enters the thyrohyoid muscle and the geniohyoid muscle.

Question 8

What do the strap muscles act on?

Answer 8

They act on they hyoid bone and the larynx.

Question 9

What can the strap muscles do to the hyoid?

Answer 9

• depress the hyoid
• with the muscle on the floor of the mouth, they can fix the hyoid

Question 10

Why is fixation of the hyoid significant?

Answer 10

It is significant because it provides a stable bony basis on which the tongue can move.

Question 11

When can we see the action of the strap muscles on the larynx?

Answer 11

We can see their action during swallowing.

• thyrohyoid elevates the thyroid cartilage towards the hyoid
• sternothyroid depresses the larynx
• rise and fall of the larynx can be seen during swallowing

Question 12

Which are the 2 muscles in the neck that have 2 bellies?

Answer 12

• digastric
• omohyoid

Question 13

How are the 2 bellies of the digastric and omohyoid muscles united?

Answer 13

They are united by a small intermediate tendon.

Question 14

What does the small intermediate tendon slide through?

Answer 14

It slides through a small fibrous fascial sling.

Question 15

Where does the anterior belly of the digastric muscle arise from?

Answer 15

It arises from a depression on the mandible beneath the chin.

Question 16

Where does the posterior belly of the digastric muscle arise from?

Answer 16

It arises from a notch on the medial side of the mastoid process on the cranial base.

Question 17

Where is the fibrous pulley that the intermediate tendon attached to?

Answer 17

It is attached to they hyoid bone.

Question 18

What is the synovial tendon surrounded by?

Answer 18

They are surrounded by a synovial sheath to minimize friction.

Question 19

Describe the nerve supply to the 2 bellies of the digastric muscles.

Answer 19

They are supplied by 2 different nerves and this shows that they have differing developmental origins.

Question 20

Where does the anterior belly of the digastric muscle recieve its nerve supply from?

Answer 20

From a small branch of the mandibular division of the trigeminal nerve.

Question 21

Aside from the anterior belly of the digastric nerve, what other muscle does the mandibular division of the trigeminal nerve (Viii) supply?

Answer 21

Supplies the mylohyoid muscle in the floor of the mouth.

Question 22

What is the posterior belly of the digastric nerve supplied by?

Answer 22

It is supplied by the facial nerve (VII)

Question 23

What does the action of the digastric muscle depend on?

Answer 23

It depends on whether or not the hyoid bone is fixed.

Question 24

What is the action of the digastric muscle when the hyoid bone is unfixed?

Answer 24

The muscle raises that bone – this action is seen during swallowing.

Question 25

What is the action of the digastric muscle on the fixed hyoid bone?

Answer 25

The digastric muscle + infrahyoid strap muscles on a fixed hyoid bone –> opens the mouth by lowering the mandible.

Question 26

What are the bellies of the omohyoid muscle called?

Answer 26

They are called the superior and inferior belies and these are united by a small intermediate tendon as well.

Question 27

Where does the inferior belly arise from?

Answer 27

It arises from the upper part of the scapula and passes forwards over the root of the neck.

Question 28

Where does the superior belly of the omohyoid arise from?

Answer 28

It arises from the inferior border of the hyoid bone.

Question 29

Where does the fascial sling that the intermediate tendon of the omohyoid muscle passes through attach to?

Answer 29

It attaches to the fascia on the deep surface of the sternocleidomastoid muscle.

Question 30

How does the omohyoid muscle act on the hyoid bone?

Answer 30

In the same way as the strap muscles and it also has the same nerve supply as the strap muscles.

Question 31

What do the lymph nodes in the neck lie in close relationship with?

Answer 31

They lie in close relationship with the jugular vein and either the digastric or omohyoid muscles.

Question 32

Where do lymph nodes lying above the digastric muscles belong to?

Answer 32

They belong to the floor of the mouth.

Question 33

Where is a deep group of cervical lymph nodes strung along?

Answer 33

Strung along the internal jugular vein and carotid sheath.

Question 34

Where do the deep group of cervical lymph nodes recieve blood supply from?

Answer 34

From more superficial groups of regional lymph nodes in the neck.

Question 35

How are the superficial groups of regional lymph nodes in the neck divided?

Answer 35

They are divided descriptively into 4 groups.

Question 36

What are the regional nodes behind the internal jugular vein called?

Answer 36

They are called the posterior nodes.

Question 37

What are the regional nodes in front of the internal jugular vein called?

Answer 37

They are called the anterior nodes.

Question 38

What are the regional nodes that are the upper members of each group called?

Answer 38

They are called superior nodes.

Question 39

What are the regional nodes that are the lower members of each group called?

Answer 39

They are called inferior nodes.

Question 40

What is the jugulodigastric node?

Answer 40

This is the node that lies in the angle between the digastric and the jugular vein.

Question 41

What drains into the jugulodigastric node?

Answer 41

Lymphatics from the tonsil and the back of the tongue.

Therefore this node can become painful and enlarged during tonsilitis.

Question 42

What group of nodes does the jugulodigastric nodes belong to?

Answer 42

It belongs to the anteroposterior group.

Question 43

Where does the anteroinferior group lie?

Answer 43

Lies just above the clavicle.

Question 44

What is the anteroinferior group of nodes also called?

Answer 44

It is also called the supraclavicular nodes.

Question 45

Why are the supraclavicular nodes important?

Answer 45

Because some of the trunk and the upper limb lymph drains through them on its way to the great neck veins.

Question 46

What can we say about cancer of the breast that has a secondary deposit in a supraclavicular node?

Answer 46

We can say that it has already invaded the thoracic cavity through the internal thoracic nodes.

Question 47

What other type of cancer other than breast cancer can we find a secondary deposit of in the supraclavicular nodes?

Answer 47

Carcinoma of the stomach.

Question 48

What is another named node of the postero-inferior group?

Answer 48

The jugulo-omohyoid node.

Question 49

How does venous drainage from the lower facial region and the temple pass into the neck?

Answer 49

Through the retromandibular vein and the posterior auricular vein.

Question 50

Where does the retromandibular vein divide?

Answer 50

It divides deep to the parotid gland.