Azygos venous system and great vessels of the neck

Question 1

What does the aortic arch divide into?

Answer 1

Arch of the aorta splits into brachiocephalic trunk (l and r common carotid artery and l and r subclavian artery), pulmonary trunk (r and l pulmonary arteries), superior vena cava

Question 2

Where do the common carotid arteries birfurcate?

Answer 2

C4 - into l and r internal and external carotid arteries

Question 3

Internal carotid arteries characteristics

Answer 3

• No branch in neck
• Enters cranial cavity through carotid canal to contribute in blood supply of brain
• Dilated proximally to form carotid sinus - baroreceptor
• Atherosclerosis of carotid arteries - arteries narrowed
• Carotid artery endarterectomy

Question 4

External carotid arteries characteristics

Answer 4

• 8 branches to face and scalp:
• Superior thyroid arteries
• Ascending pharyngeal arteries
• Lingual arteries
• Facial arteries
• Occipital arteries
• Posterior auricular arteries
• Maxillary arteries
• Superficial temporal arteries
• Bleeding due to scalp injury
• Extradural haematoma due to injury of middle meningeal artery
• L and R subclavian arteries = l and r vertebral arteries and l and r thyrocervical trunks

Question 5

Vertebral arteries characteristics

Answer 5

• No branch in neck
• Enters vertebrae transverse foramina from 6th cervical vertebrae and cranial cavity through foramen magnum
• Divided into - preforaminal or prevertebral (V1), foraminal or vertebral (V2), atlantal or suboccipital (V3) and intracranial (V4)

Question 6

Major neck veins

Answer 6

• EJV
• ANterior jugular veins
• IJV
• Subclavian veins
• Brachiocephalic veins

Question 7

EJV

Answer 7

• Face and scalp
• Formed by retromandibular and posterior auricular veins by mandible
• Drains to subclavian vein

Question 8

AJV

Answer 8

• Drains to EJV or subclavian

- L and R AJV form jugular venous arch

Question 9

IJV

Answer 9

• Brain, ant face, cervical viscera
• Continuation of sigmoid sinus
• In carotid sheath
• Joins with subclavian to form brachiocephalic veins at venous angle
• Inferior bulb of IJV at inferior end
• Inferior bulb has bicuspid valve to allow blood to heart
• Raised JVP = right sided heart pressure and venous hypertension

Question 10

Carotid sheath

Answer 10

• Wrapping of neurovascular bundle from cranium to neck

- Contains carotid arteries, IJV, vagus nerve, deep cervical lymph nodes, carotid sinus nerve, sympathetic nerve fibres

Question 11

Subclavian veins

Answer 11

• Drains upper limb
• Continuation of L and R axillary veins
• Starts at lateral border of rib 1
• Joins IJV to form l and r brachiocephalic veins
• Central venous line inserted here

Question 12

Brachiocephalic veins

Answer 12

• Formed by union of IJV and subclavian veins
• L and R brachiocephalic veins form SVC
• L is longer than R because it crosses obliquely from l to r anterior to arch of aorra
• Drains head, neck and upper limb - SVC - RA
• Can be obstructed

Question 13

What does azygos venous system drain

Answer 13

Drains back and thoracoabdominal walls and mediastinal viscera

Question 14

Azygos vein characteristics

Answer 14

• Unpaired
• Between SVC and IVC
• Arises from posterior IVC
• Ascends to RHS of inferior 8 thoracic vertebrae in post mediastinum
• Arches over root of right lung to join the SVC
• Drains thorax and abdomen
• Tributaries include hemi-azygos veins, lumbar veins, mediastinal, oesophageal and bronchial veins

Question 15

Hemi-azygos vein characteristics

Answer 15

• Unpaired
• From renal vein
• Ascends to T9 thoracic aorta
• Receives from 3 posterior inferior intercostal veins, oesophageal veins and mediastinal veins

Question 16

Accessory heimi-azygos vein characteristics

Answer 16

• Unpaired
• Begins in 4 or 5th intercostal space
• Descends on LHS from T5 to T8
• Receives from 4-8 intercostal veins and l bronchial veins

Question 17

Where does internal carotid artery bifurcate?

Answer 17

c4