Lecture 2: Arterial supply + venous drainage of face/head Flashcards

1
Q

Common Carotid Artery

A

Ascends with neck to superior border of thyroid cartilage/C3-C4 vertebral level

  • Birfucates –> internal/external carotid a
  • As it ascends, positioned MEDIAL to IJV.
  • Vagus n is POSTERIOR, between artery and vein
  • All 3 in carotid sheath
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2
Q

Internal carotid artery

A
  • Passes deep to posterior belly of digastric and stylohyoid muscles
  • Crossed by hypoglossal n (passes superficial to both internal and external carotid arteries)
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3
Q

ICA p 2

A
  • Ascends anterior to transverse process of C1-C3 to reach base of skull; passes into carotid canal (petrous temporal bone) to reach cranial cavity (middle cranial fossa)
  • No branches in neck
  • Major source of blood to brain and orbit
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4
Q

Four parts of ICA

A
  1. Cervical part: bifurcation of CCA to lower end of carotid canal
  2. Petrous part: pass through carotid canal (in petrous temporal bone)
  3. Cavernous: course through cavernous sinus (along body of sphenoid)
  4. Cerebral: after piercing dura (near anterior clinic process), ICA gives off ophthalmic a before terminating as anterior and middle cerebral arteries
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5
Q

Ophthalmic a

A

Emerges from internal carotid immediately upon leaving cavernous sinus

  • Enters orbit via optic canal
  • Several branches (lacrimal, ciliary, ethmoidal, muscular) + 2 to forehead: supraorbital and supratrochlear
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6
Q

External carotid a

A

Deep to posterior belly of digastric and stylohyoid muscles
- Posterior to ramus of mandible, embedded in parotid gland
Mainly supply structures external to skull

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7
Q

ECA branches

A
  1. Superior thyroid a
  2. Ascending pharyngeal a
  3. Lingual a
  4. Facial a
  5. Occipital a
  6. Posterior auricular a
  7. Superficial temporal a
  8. Maxillary a
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8
Q

Superior thyroid a

A

Passes anteroinferior, DEEP to infra hyoid muscles to reach thyroid gland
- Also gives off branches to local muscles – gives rise to superior laryngeal a (larynx)

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9
Q

Ascending pharyngeal a

A

Near origin of ECA and smallest branch

  • Ascends between ICA and pharynx to base of skull
  • Sends branches to pharynx
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10
Q

Lingual a

A

Arises from anteromedial aspect of ECA, between superior thyroid and facial arteries

  • Crossed by hypoglossal n
  • Passes deep to stylohyoid and posterior digastric muscles before disappearing deep to hyoglossus
  • Passes to inferior aspect of tongue -> deep lingual and sublingual branches
  • Primary blood supply to tongue and floor of oral cavity
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11
Q

Facial a

A

Deep to digastric and stylohyoid muscles and medial to ramus/angle of mandible

  • Passes along lower border of mandible, where it has a close relationship to submandibular gland
  • Prior to entering face, gives off submental a
  • Hooks around inferior border of mandible and enters face
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12
Q

Facial branches of facial a

A

Inferior labial a
Superior labial a
Lateral nasal branch
Angular a
– terminal part of facial a as it travels to medial angle of eye
–Forms anastomosis with ophthalmic a (branch of ICA)

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13
Q

Occipital a

A

Arises from posterior aspect of ECA, opposite origin of facial a

    • Passes posteriorly, parallel and deep to posterior belly of digastric as it courses to posterior scalp
  • -Several branches that supply structures in area, scalp+muscles in the area
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14
Q

Posterior auricular a

A

Small posterior branch, ascends posteriorly between EAM and mastoid process
- several branches to structures in area, including posterior auricle and muscles in the area

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15
Q

Superficial temporal a

A

Originates within parotid gland

  • Between neck of mandible and EAM, enters temporal fossa and terminates by dividing into frontal/parietal branches
    • TRANSVERSE FACIAL A- superficial to masseter, inferior to zygomatic arch
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16
Q

Maxillary a

A
  • Arises within parotid gland, posterior to neck of mandible
  • Medial to mandible to enter infra temporal fossa
  • Within infra temporal fossa, may pass superficial OR deep to lateral pterygoid muscle
  • Divided into 3 parts by lateral pterygoid muscle
  • Passes through pterygomaxillary fissure to enter pterygopalatine fossa
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17
Q

Maxillary a (1st or mandibular part)

A
  1. Deep auricular a - pierces wall of EAM, supplies lateral surface of tympanic membrane
  2. Anterior tympanic a - traverses petrotympanic fissure and supplies medial surface of tympanic membrane
  3. Middle meningeal a - traverses foramen spinosum to enter middle cranial cavity, blood supply: dura mater
  4. Accessory meningeal a - foramen ovale -> middle cranial cavity -> dura mater
  5. Inferior alveolar a: mandibular foramen -> mandibular canal; mandibular teeth and gingiva

Before passing into bone, gives off mylohyoid branch (travels with n)
2nd premolar: divides into incisor/incisive and mental branches
Incisive branch to midline–> anterior teeth/gingiva
Mental branch -> mental foramen -> muscles/skin of chin

18
Q

Max artery 2nd or pterygoid part

A
  1. Masseteric a: superior to mandibular notch –> deep surface of masseter muscle
  2. Deep temporal a (anterior and posterior): ascends to supply temporal muscle
  3. Pterygoid arteries: supply pterygoid muscles
  4. Buccal a: buccinator
19
Q

Max Artery 3rd or Pterygopalatine Part

A
  1. Posterior superior alveolar a: traverses alveolar foramen; supplies max molars, premolars, adjacent ging tissue as well as lining of maxillary sinus
  2. Infraorbital a: passes through inferior orbital fissure –> infraorbital groove –> infraorbital canal –> infraorbital foramen; supplies inferior eyelid, lateral nose and superior lip; along course gives rise to anterior alveolar a (max canine, incisors and adj gingival tissue)
    BOTH supply max sinus
  3. Descending palatine a: descends through greater palatine canal –> greater and lesser palatine arteries and pass through same named foramina; supply mucous membrane/glands of soft and hard palate and maxillary gingival tissue
  4. Artery of pterygoid canal: passes through pterygoid canal; supplies the nasopharynx, pharyngotymapnic tube and tympanic cavity
  5. Pharyngeal a: passes through palatovaginal canal; supplies nasopharynx
  6. Sphenopalatine a: terminal branch of maxillary a, passes through sphenopalatine foramen to reach nasal cavity; supplies portion of nasal cavity, including nasal septum and anterior hard palate
20
Q

Venous Drainage: Cranial Cavity

A

Blood from brain empties into dural venous sinuses

  • Blood from scalp may also communicate with dural venous sinuses via emissary veins, pass through openings in cranial wall
  • — Emissary veins allow communication between veins outside skull and dural venous sinuses (inside skull) –> potential spread of infection
  • Diploic veins occupy channels in diploe of cranial bones
21
Q

Dural venous sinuses

A

Endothelial-lined spaces between periosteal and meningeal layers of dura

22
Q

Superior sagittal sinus

A

Occupies convex superior attaches border of falx cerebri

-Begins near crest Galli and ends near internal occipital protuberance, at confluence of sinuses

23
Q

Inferior sagittal sinus

A

Occupies concave inferior free border of falx cerebri

-Ends in straight sinus

24
Q

Straight sinus

A

Formed by union of inferior sagittal sinus and great cerebral vein

  • Joins confluence of sinuses
  • Located at junction of falx cerebri and tentorium cerebelli
25
Q

Occipital sinus

A

Occupies attached border of falx cerebelli and ends superiorly in confluence of sinuses

26
Q

Confluence of sinuses

A

Union of superior sagittal, straight, occipital and transverse sinuses

27
Q

Transverse sinus

A
  • Passes from confluence of sinuses, laterally along attached margin of tentorium cerebelli
  • Laterally, where sinus passes from tentorium cerebelli, it becomes sigmoid sinus
28
Q

Sigmoid sinus

A
  • Originates where transverse sinus leaves tentorium cerebelli
  • S-shaped as it descends and passes through in posterior cranial fossa
  • Continues inferiorly as IJV after traversing jugular foramen
29
Q

Cavernous Sinus

A

Located on either side of sella turcic (sphenoid)

-Drains posteroinferiorly through superior and inferior petrosal sinuses

30
Q

Superior petrosal sinus

A
  • Located along anterior margin of tentorium cerebelli

- Passes from posterior end of cavernous sinus and terminates where it joins transverse sinus

31
Q

Inferior petrosal sinus

A

Originates at posterior end of cavernous sinus, passes inferiorly and empties into proximal aspect of IJV

32
Q

Cavernous sinus

A

Structures passing cavernous sinus include:
1. ICA
2. Internal carotid plexus (sympathetic nerves)
3. CN3
4. CN4
5. CN6
6. CNV1
7. CNV2
these structures separated from blood in sinus by endothelial cells

33
Q

Superficial Temporal Vein

A

Begins from widespread network of veins in scalp

  • Drains blood from scalp, anterior to auricle
  • Near auricle, superficial temporal vein enters parotid gland
34
Q

Maxillary Vein

A

Short trunk accompanying 1st part of maxillary artery

  • Derived from union of veins of pterygoid venous plexus (deep network of vein in infra temporal fossa)
  • Union of maxillary and superficial temporal veins occurs within parotid gland and forms retromandibular vein
35
Q

Retromandibular vein

A

Courses posterior to ramus of mandible and descends through parotid gland, superficial to ECA and deep to facial n
Divides into anterior and posterior branches

36
Q

Posterior branch of retromandibular vein

A

Joins posterior auricular vein –> external jugular vein (union occurs just after exiting parotid gland)

37
Q

Anterior branch of retromandibular vein

A

Joins facial vein which drains into IJV (sometimes called common facial vein)

38
Q

Facial Vein

A

Formed by union of supraorbital and supratrochlear veins at medial angle of eye

  • Angular vein from its origin (medial eye) -> along lateral aspect of nose
  • Receives several veins (superior, labial, inferior labial, submental veins) before uniting with anterior branch of retromandibular vein
  • Communicates with pterygoid venous plexus
39
Q

Deep Facial Veins and Pterygoid Venous Plexus

A
  • Facial vein communicates with pterygoid venous plexus via deep facial veins and infraorbital vein
    -From pterygoid venous plexus, blood can reach cavernous sinus
    POTENTIAL SPREAD OF INFECTION
40
Q

Routes for Spread of Infection of Embolism

A
  1. Facial vein –> deep facial vein –> pterygoid venous plexus –> emissary vein –> cavernous sinus
  2. Infraorbital vein –> pterygoid venous plexus –> emissary vein –> cavernous sinus
  3. Supraorbital vein –> ophthalmic vein –> cavernous sinus