Head and Neck Practical II

Question 1

Why does irritation of parietal pleura or parietal peritoneum refer to the shoulder?

• nerves involved
• where they come from?

Answer 1

-phrenic and supraclavicular nerves have a common origin from C3 and C4 spinal cord segments

Question 2

What 3 infrahyoid muscles are innervated by the ansa cervicalis?

Which one is not?

Answer 2

1. Sternohyoid
2. Omohyoid
3. Sternothyroid

NOT -> thyrohyoid (cranial spinal nerve 1 via hypoglossal nerve)

Question 3

Which muscle inserts onto the oblique line of the thyroid cartilage?

Answer 3

Sternothyroid

Question 4

Where is the opening for a tracheotomy made?

Answer 4

B/w the infrahyoid muscles in the midline

Question 5

Insertion and Innervation for digastric muscle

Answer 5

1. Anterior belly
   - insertion -> digastric fossa of mandible
   - innv -> mylohyoid nerve (branch of V3)
2. Posterior belly
   - insertion -> mastoid process
   - innv -> CN VII

Both bellies attach to each other by intermediate tendon which is attached to the greater horn of hyoid bone

Question 6

Submandibular triangle

-contents and boundaries

Answer 6

- Contents
○ Submandibular gland
○ Facial artery
○ Facial vein
○ Stylohyoid muscle
○ Part of CN XII
○ Lymph nodes

• Boundaries
  ○ Superior - inferior border of the mandible
  ○ Anteroinferior - anterior belly of the digastric muscles
  ○ Posteroinferior - posterior belly of the digastric muscles
  ○ Superficial (roof) - superficial layer of deep cervical fascia
  ○ Deep (floor) - mylohyoid muscle and hypoglossus muscle

Question 7

Submental triangle

-contents and boundaries

Answer 7

• Contents
  ○ Submental lymph nodes
• Unpaired triangle; crosses midline
• Boundaries
  ○ Right and left - anterior bellies of right and left digastric muscle
  ○ Inferior - hyoid bone
  ○ Superficial (roof) - superficial layer of deep cervical fascia
  ○ Deep (floor) - mylohyoid muscle

Question 8

Carotid triangle

-contents and boundaries

Answer 8

- Contents
○ Carotid arteries (common, internal, external)
○ Branches of external carotid artery
○ Part of hypoglossal nerve
○ Branches of vagus nerve

• Boundaries
  ○ Inferomedial - superior belly of the omohyoid muscle
  ○ Inferolateral - anterior border of the sternocleidomastoid
  ○ Superior - posterior belly of digastric muscle

Question 9

Cricothyroid muscle innervated by?

Answer 9

External branch of superior laryngeal nerve

Question 10

Carotid sheath contains?

Answer 10

1. the common carotid artery as well as the internal carotid artery
2. internal jugular vein
3. the vagus nerve (CN X)
4. the deep cervical lymph nodes

Question 11

4 branches of external carotid (LOFS)

Answer 11

1. Superior thyroid
   - gives rise to superior laryngeal artery
2. Lingual artery
3. Facial artery
4. Occipital artery

Question 12

Where is the carotid sinus found?

Carotid body?

Functions?

Answer 12

Carotid sinus

• at bifurcation of common carotid artery
• dilation of origin of internal carotid
• contains pressoreceptors that monitor BP
• innervated by IX and X

Carotid body

• monitors changes in O2 and CO2 concentration in blood
• Innervated by IX and X