Blood Vessels of Head and Neck

Question 1

Describe the route of IJV and EJV relative to SCM

Answer 1

• External jugular vein runs above sternocleidomastoid

- Internal jugular vein and carotid artery covered by sternocleidomastoid

Question 2

Where do subclavian and common carotid arteries arise from

Answer 2

brachiocephallic trunk

Question 3

Name arteries that arise from subclavian artery

Answer 3

Vertebral, internal thoracic arteries and thyrocervical trunk

Question 4

Name the branches off the thyrocervical trunk

Answer 4

• Ascending cervical and transverse cervical supply the neck
• Suprascapular artery supplies shoulder
• Inferior thyroid supplies lower pole of thyroid gland

Question 5

Describe the route of the vertebral arteries

Answer 5

• Vertebral arteries arise from the subclavian arteries on left and right
• Ascend in the neck through transverse foramina in cervical vertebrae C6-C1 and pass through the foramen magnum
• Continues as the basilar artery in the skull

Question 6

Distinguish between internal and external carotid arteries in the neck

Answer 6

Internal carotid artery gives no branches off in the neck

Question 7

Describe the route of the internal carotid artery

Answer 7

• Internal carotid artery gives no branches off in neck
• Enter skull through carotid canal
• Bother vertebral and internal carotid arteries supply the brain and enter circle of Willis
• Anastomoses of arteries in case one gets blocked

Question 8

State the arrangement of internal jugular vein relative to common carotid in the neck

Answer 8

Internal jugular lies lateral to the common carotid mostly under sternocleidomastoid

Question 9

At what level does common carotid artery bifurcate

Answer 9

• Bifurcates at about the level of the superior border of thyroid
• At C4 level within carotid triangle

Question 10

What complications occur at point of common carotid artery bifurcation

Answer 10

• At point of bifurcation, common site of atheroma formation
• Causes narrowing (stenosis) of the artery creating turbulence - can be heard from stethescope
• Rupture of the clot can cause an embolus to travel to brain
• Cause TIA or stroke

Question 11

State the location and action of carotid sinus

Answer 11

• Swelling at region of bifurcation - stretching of arterial wall
• Location of baroreceptors for detecting changes in arterial blood pressure

Question 12

State the location and action of carotid body

Answer 12

• Peripheral chemoreceptors which detect arterial oxygen

- Located near the bifurcation of carotid artery

Question 13

State the origin and branches of ophthalmic artery

Answer 13

• Ophthalmic artery branches from internal carotid artery

- Supratrochlear and supra-orbital artery are branches of ophthalmic artery

Question 14

State the branches of external carotid artery

Answer 14

• 6 branches
  
  • superior thyroid
  • lingual
  • facial
  • ascending pharyngeal
  • occipital
  • posterior auricular
• +2 terminal branches
  
  • superficial temporal
  • maxillary

Question 15

State the blood supply to the scalp

Answer 15

• From internal carotid:
  
  • supra-orbital
  • supratrochlear
• From external carotid:
  
  • superficial temporal
  • posterior auricular
  • occipital

Question 16

State the layers of the scalp

Answer 16

• Skin
• Connective tissue (dense)
• Aponeurosis
• Loose connective tissue
• Periosteum

Question 17

State where blood vessels lie in the scalp

Answer 17

• Mainly dense connective tissue layer

Question 18

Describe how injuries to the scalp can cause raccoon eyes

Answer 18

• Blood may seep in the loose connective tissue layer below the aponeurosis
• Occipitaofrontalis muscle is not inserted into bone, but into the orbit
• Blood flows through the loose connective tissue to the orbit

Question 19

Name 2 branches of the maxillary artery

Answer 19

• Middle meningeal

- Sphenopalatine (nasal septum)

Question 20

Describe the blood supply to the nasal septum

Answer 20

• Anastomosis of arteries of Kiesselbach area
• Most important branches are septal branch of sphenopalatine artery (from maxillary nerve) and anterior ethmoidal arteries (from ophthalmic artery)
• Kiesselbach area common site for nose bleed (epistaxis)
  
  • Septal branch sources of severe bleeds

Question 21

What artery supplies the dura and skull

Answer 21

Middle meningeal artery - lies between inner table and dura matter

Question 22

State how the venous drainage of the eye occur

Answer 22

Supraorbital and supratrochlear veins unite at medial angle of eye to form angular vein which drains into the facial vein

Question 23

Explain diploic and emissary veins

Answer 23

• Diploic veins drain the skull bone to the dural venous sinuses
• Emissary veins connect the veins in the scalp to the dural venous sinuses within the skull
  
  • Emissary veins are valveless
• Infection from scalp can spread to the cranial cavity and affect meninges

Question 24

Explain the venous drainage of the facial vein

Answer 24

• Veins of the face are valveless
• At medial angle of eye, facial vein communicates with superior ophthalmic
  
  • Drains into cavernous sinus
• Deep facial veins drain into pterygoid venous plexus
  
  • Infection from facial vein can spread to dural venous sinuses
    
    • Thrombophlebitis of facial vein - infected clot can travel to intracranial venous system

Question 25

Explain the danger triangle of the face

Answer 25

- Between the eyebrows down to the edge of the mouth | - Infections in this region of the face can spread through the venous system to the dural venous sinuses

Question 26

State the importance of the carotid triangle surgically

Answer 26

- Important for surgical approach of the carotid arteries or internal jugular vein - Can also access vagus and hypoglossal nerves via carotid triangle - Carotid pulse can be felt in carotid triangle just below bifurcation

Question 27

State the borders of the carotid triangle

Answer 27

- Superior border - posterior belly of digastric muscle - Lateral border - medial border of SCM - Inferior border - superior belly of omohyoid muscle

Question 28

Explain how and when a carotid sinus massage is used

Answer 28

- Terminate supraventricular tachycardia - Massaging tricks peripheral receptors in thinking blood pressure has increased - Stimulates glossal pharyngeal nerve to activate parasympathetic system through brainstem - Stimulates vagus nerve to lower heart rate

Question 29

How is jugular venous pressure measured

Answer 29

- Use right internal jugular vein - Direct connection to right atrium - Patient at 45˚ angle - head slightly to the left - IJV largely hidden by sternocleidomastoid - Pulsation observed through muscle - Height from sternal angle + 5cm - Do not palpate as that is carotid artery

Question 30

Explain the course of the internal carotid artery

Answer 30

- Internal carotid artery enters skull through carotid canal at petrous part - Turns medially and horizontally - Enters the cranial cavity then makes S-shaped bend - Course through the cavernous sinus - Continues into circle of Willis

Question 31

Through which opening does the vertebral artery pass through in the skull

Answer 31

- Vertebral artery pass through the foramen magnum | - Continues as basilar artery into circle of Willis

Question 32

Explain the passage of the middle meningeal artery through the skull

Answer 32

- Middle meningeal artery runs alongside pterion area - Easily fractured so risk of rupture of middle meningeal artery - Passes through foramen spinosum

Question 33

Through which opening does the internal jugular vein pass through in the skull

Answer 33

Jugular foramina