HNS24 Vasculature And Lymphatic Of Head And Neck

Question 1

General rule of learning blood supply

Answer 1

Origin
—> Structures supplied
—> Branches
—> Branch details
—> Clinical examples

1. External carotid
2. Internal carotid
3. Subclavian branches
4. Veins
5. Lymphatics

Question 2

Aortic arch supply to head and neck

Answer 2

Left:

• Left subclavian
• Left common carotid —> external + internal

Right:
- Brachiocephalic (Innominate)
—> Right subclavian + Right common carotid —> external + internal

Variants:

• Left carotid and Brachiocephalic have common origin (1%-22%)
• Left carotid originates from Brachiocephalic (9%)

Question 3

Carotid arteries landmarks

Answer 3

Bifurcation of carotid

• Upper margin of thyroid cartilage
• C4 level

Question 4

(4 parts of Internal carotid artery)

Answer 4

(1. Cervical
2. Petrous
3. Cavernous
4. Cerebral)

Question 5

External carotid artery

Answer 5

Supply:

1. Scalp
2. Face
3. Maxilla
4. Tongue
5. Glands
6. Pharynx

Branches (總共8 branches):
Anterior
1. Facial
2. Maxillary (分3段, 總共13 branches)
- 1st (Mandibular)
- 2nd (Pterygoid / muscular)
- 3rd (Pterygopalatine)
3. Superior thyroid
4. Lingual
5. Ascending pharyngeal

Middle:
1. Superficial temporal (頭頂scalp)

Posterior:

1. Posterior auricular (scalp)
2. Occipital (scalp)

Question 6

Maxillary artery branches (X rmb detail branches)

Answer 6

分3段

1. Mandibular (最先段) —> posterior to Lateral pterygoid muscle
   - deep auricular
   - anterior tympanic
   - ***middle meningeal
   - accessory meningeal
   - inferior alveolar
2. Pterygoid / Muscular —> within Lateral pterygoid muscle (supply muscles)
   - anterior deep temporal branches
   - posterior deep temporal branches
   - pterygoid branches
   - masseteric artery
   - buccinator artery
3. Pterygopalatine (最後段) —> anterior to Lateral pterygoid muscle
   - posterior superior alveolar artery
   - infraorbital artery
   - artery of pterygoid canal
   - greater (descending) palatine / pharyngeal artery
   - ***sphenopalatine artery

Question 7

Internal carotid artery

Answer 7

Supply:

1. Brain
2. Eye
3. Nasal cavity
4. Scalp

Branches:
1. Anterior and Middle cerebral artery —> Circle of Willis
2. Ophthalmic arteries
—> Ocular group
—> Orbital group

Question 8

Circle of Willis contents

Answer 8

Internal carotid arteries x2
Anterior cerebral arteries x2
Posterior cerebral arteries x2
Anterior communicating artery ***x1
Posterior communicating artery x2

Question 9

Ophthalmic artery (X rmb detail branches)

Answer 9

Runs alongside CN2 via Optic canal
—> Ocular group
—> Orbital group

1. Ocular branches (eyeballs):
   - Central artery of retina (end artery)
   - Short / Long posterior ciliary arteries
   - Anterior ciliary artery
   - Superior / Inferior muscular arteries
2. Orbital branches:
   - **Anterior / Posterior ethmoidal artery
   - Dorsal nasal artery
   - Supratrochlear artery
   - Supraorbital artery
   - **Zygomatico-facial artery
   - ***Zygomatico-temporal artery
   - Muscular artery

Question 10

Subclavian branches

Answer 10

1. Vertebral arteries (transverse foramina)
   - Basilar artery
2. Internal thoracic artery
3. Thyrocervical trunk
   - Inferior thyroid artery (Superior: branch of external carotid)
   - Ascending cervical artery
4. Costocervical trunk
   - Deep cervical artery

Question 11

Vertebral artery

Answer 11

• Ascend through transverse foramina of upper 6 cervical vertebrae
• Enters cranium through foramen magnum
• 2 Vertebral arteries —> Basilar artery —> 2 Posterior Cerebral arteries
  —> contribute to Circle of Willis

Question 12

Anastomoses regions

Answer 12

1. Face
2. Scalp
3. Nasal cavity
4. Thyroids + parathyroid glands
5. Oral cavity
6. Palate

Question 13

Face anastomoses (Superior to Inferior) (External + Internal)

Answer 13

External carotid

1. Facial artery
2. Maxillary artery
3. Superficial temporal artery

Internal carotid
4. Ophthalmic artery

Question 14

Scalp anastomoses (Anterior to Posterior) (External + Internal)

Answer 14

Occurs between L/R branches, different branches of same / different origin

External carotid (Posterior)

1. Superficial temporal
2. Occipital
3. Posterior auricular

Internal carotid (Anterior)
4. Upper branches of Ophthalmic artery
—> Supratrochlear
—> Supraorbital
—> Zygomatico-temporal branches

Question 15

Nasal cavity anastomoses (External + Internal)

Answer 15

External carotid
1. Facial
—> Superior labial
—> Lateral nasal

2. Maxillary
   —> Sphenopalatine
   —> Greater palatine

Internal carotid
3. Ophthalmic artery
—> Ethmoidal branches

Clinical significance
- Kiesselbach’s area (Little’s area) —> common for nosebleeds

Question 16

Thyroid and Parathyroid blood supply (External + Subclavian)

Answer 16

1. Superior thyroid artery (from External carotid)
   —> supply Superior thyroid
2. Inferior thyroid artery (from Subclavian via Thyrocervical trunk)
   —> supply Inferior thyroid + Parathyroid
3. Thyroid ima artery (1-2% of population)
   —> supplies Inferior thyroid
   —> Clinical significance: cut vessel during neck surgery (thyroidectomy) —> uncontrollable bleeding

Question 17

Oral cavity blood supply anastomoses (External ONLY)

Answer 17

***External carotid ONLY!!!

1. Facial
   —> superior labial
   —> lateral nasal
2. Maxillary artery
   —> superior / inferior alveolar buccal
3. Lingual artery
   —> dorsal lingual
   —> deep lingual
   —> sublingual

Question 18

Palate blood supply

Answer 18

***Maxillary artery ONLY (between branches of sub-branch) —> rich blood supply

1. Sphenopalatine
   (- after passing through nasal cavity enters palate through Incisive foramen)
2. Greater palatine
   (- merges onto palate through Greater palatine foramen, passing forward to join Sphenopalatine artery)
3. Lesser palatine
   (- passes through Lesser palatine foramen and supply soft palate)

Question 19

Carotid Bruit

Answer 19

Carotid stenosis

Clinical significance: Stroke risk
3 ways:

1. Narrow artery
   —> ↓ blood flow
2. Thrombosis
   - roughen arterial wall
   —> blood clots
   —> ↓ blood flow
3. Embolism
   - plaque deposits / blood clots break away
   —> travel to brain
   —> ↓ blood flow within brain

Diagnosis

• Doppler ultrasound
• Digital angiography

Question 20

Central artery of retina occlusion

Answer 20

ICA —> Ophthalmic arteries —> Ocular branch

1. Central artery of retina
   - pierces the Optic nerve —> run inside optic nerve
   - emerges at centre of optic disc
   - End-artery (ONLY blood supply to retina)
   - emboli from Carotid can travel to it
2. Ciliary artery
   - supply Conjunctiva, Sclera, Choroid

Question 21

Venous drainage: Overview

Answer 21

Brain and meninges:

1. Cerebral veins
2. Dural venous sinuses

Head and face:
1. Veins follow arteries and have same names (e.g. facial artery and vein)

Neck:

1. Anterior jugular veins
2. External jugular veins
3. Internal jugular veins
4. Vertebral veins

Question 22

Veins of face

Answer 22

1. Facial vein:
   - Union of Supratrochlear + Supraorbital vein
   —> Angular vein
   —> Facial vein
   —> communicates with Ophthalmic, Infraorbital, Deep facial veins
   —> directly into Internal jugular vein
   OR
   —> via Common Facial vein first (variable) —> Internal jugular vein
2. Retromandibular vein:
   - Union of Superficial temporal + Maxillary vein
   - divided into:
   —> Anterior division: joins Facial vein —> Common facial vein
   —> Posterior division: joins Posterior auricular vein —> External jugular vein

Question 23

Anterior jugular vein

Answer 23

Anterior neck drainage

Starting point:
Union of Mental veins (under chin)
—> communications between 2 Anterior jugular veins at Jugular Venous Arch
—> **External jugular vein / **Subclavian vein directly

Question 24

External jugular vein

Answer 24

Structures outside skull + External face drainage

Lies ***superficial to Sternocleidomastoid (SCM)

Starting point:
**Parotid gland (under mandible)
—> **Subclavian vein

Question 25

Internal jugular vein

Answer 25

Starting point: ***Jugular foramen (at base of skull, as continuation of Sigmoid sinus) —> ***Subclavian vein —> ***Brachiocephalic vein Travels down neck in Carotid sheath with Internal / Common carotid arteries + Vagus nerve

Question 26

Vertebral vein

Answer 26

``` Starting point: Small veins (at base of skull) —> Brachiocephalic vein ``` Travels down transverse foramina (alongside Vertebral arteries) starting at C1 —> although NOT pass through foramen magnum

Question 27

Dural venous sinuses

Answer 27

- Formed between 2 layers of dura mater - receive blood from brain - Drain into ***Internal jugular vein 1. Superior / Inferior sagittal 2. Straight —> Confluence of sinuses —> Transverse —> Sigmoid 3. Superior / Inferior petrosal 4. Basilar 5. Sphenoparietal ***6. Cavernous

Question 28

***Cavernous sinus

Answer 28

- Large paired sinus - in Middle cranial fossa (side of body of Sphenoid bone) Receives blood from: 1. Cerebral veins 2. Ophthalmic veins (from orbit) 3. Emissary veins (from pterygoid plexus) Clinical significance: 1. Connections provide infectious pathway: Extracranial sites (eyes, face) —> Intracranial locations 2. Structures in sinus are vulnerable to injury (aneurysms of internal carotid, pituitary adenoma, cavernous sinus thrombosis): Within sinus: - Internal carotid artery - CN6 On the lateral wall: - CN3 - CN4 - CN5: V1, V2

Question 29

Vertebral venous plexus

Answer 29

Internal + External vertebral venous plexus - Vertebral column drainage - receives blood from Thoracic, Abdominal, Pelvic organs Internal vertebral venous plexus - Connect with intracranial Dural venous sinuses (e.g. Occipital, Basilar sinuses) ``` Clinical significance: ***Intracranial pathway for metastasis Bloods in these valve-less veins —> allow retrograde spread of cancer cells from Thoracic, Abdominal, Pelvic regions —> Vertebral column, Spinal cord, Brain ```

Question 30

Intracranial venous connections

Answer 30

``` Clinical significance: Facial vein (no valves) connects with: 1. Ophthalmic veins 2. Infraorbital vein 3. Deep facial vein —> pass into deeper regions of head ``` Interconnections with intracranial Cavernous sinus directly / via Emissary veins Valve-less Facial vein —> infections of face —> extend to intracranial venous sinuses —> ***Cavernous sinus thrombosis

Question 31

Pterygoid venous plexus

Answer 31

Infratemporal fossa (between pterygoid muscle) Drainage: Nasal cavity, Paranasal sinuses, nasopharynx, oral cavity, teeth, muscles of mastication Receives Inferior ophthalmic vein (via Inferior orbital fissure) Important connections: Anteriorly: Facial vein (by deep facial vein) Posteriorly: Retromandibular vein (via maxillary vein) Superiorly: Cavernous sinus (by emissary veins)

Question 32

Diploic and Emissary veins

Answer 32

Diploic veins - large thin-walled, valveless veins - lying in Diploe (middle spongy layer of cranial bone) - connected to Emissary veins Emissary veins (由skull出面—>skull入面) - small valveless veins - pass through foramen in cranial bones - connect to Dural venous sinuses + Meningeal veins —> Veins external of skull Clinical significance: - Both valve-less veins - Possible route for spread of infection from outside to inside (e.g. osteomyelitis, meningitis, encephalitis) - Function as alternative pathways for venous OUTflow from intracranial structures

Question 33

Venous channels in Orbit

Answer 33

1. Superior ophthalmic veins - superior part of orbit - leaves orbit via Superior orbital fissure —> Cavernous sinus (- Supratrochlear + Supraorbital + Angular veins) 2. Inferior ophthalmic veins - smaller - inferior part of orbit (orbit floor) - leaves orbit by: —> joining Superior ophthalmic vein —> Cavernous sinus OR —> passing though inferior orbital fissure —> Pterygoid venous plexus

Question 34

Lymphatic drainage pattern of head and neck

Answer 34

Superficial LN (5 groups around base of head) —> 1. Superficial cervical nodes (along ***External jugular vein (SCM)) —> Deep cervical nodes (along ***Internal jugular vein) OR 2. Deep cervical nodes directly Clinical significance: 1. Obstruction —> Lymphoedema 2. Channel for spread of malignant disease + infection of head and neck 3. Site of primary tumour

Question 35

Superficial LN (X rmb details)

Answer 35

5 groups of Superficial LN —> form a ***ring at junction of head and neck —> drain lymph from scalp + face + neck 1. Occipital 2. Mastoid (Posterior auricular nodes) 3. Pre-auricular + Parotid 4. Submandibular 5. Submental

Question 36

Superficial and Deep cervical LN

Answer 36

Superficial cervical LN: - along ***External jugular vein - Posterior + Posterolateral scalp drainage Deep cervical LN: - along ***Internal jugular vein - ALL lymph from head and neck - 2 groups: 1. Superior group (with Jugulo-digastric node / tonsilar) 2. Inferior group (with Jugulo-omohyoid node / lingual)