External carotid artery

This is a presentation of external carotid artery from a view point of a Maxillo-Facial Surgeon

1. External carotid artery Moderator: Dr Sheron M Presented by: Dr Rayan M

2. CONTENTS Introduction History Embryology Course Applied anatomy References

3. HISTORY The word carotid is derived from the Greek Kotpalv , to stupefy. The vessel has also been termed the apoplectic or sopornl artery in recognition of the common effect of compression of both carotids. Aristotle is credited as the earliest source of this observation. It was the anatomist Andreas Vesalius who first observed in systematic detail the human vascular system. His masterwork , De Humani Corporis Fabrica (1543), is considered by some to be the greatest contribution to the medical sciences.

4. External carotid artery is the chief artery which lies anterior to internal carotid artery, supplies to structures in the front of the neck and in the face. Ext e r n al c a r o tid art e ry is one of the terminal branches of the common carotid artery. INTRODUCTION

5. During the fourth and fifth wee ks of embryological development, when the pharyngeal arches form, the aortic sac gives rise to arteries – the aortic arches. The aortic sac is the endothelial lined dilation, it is the primordial vascular channel from which the aortic arches arise. EMBRYOLOGY OF ECA

6. 3rd Arch : forms common carotid artery , first (cervical) part of internal carotid artery ( rest of internal carotid arises from dorsal aorta) , and external carotid artery .

7. Right common carotid artery is a branch of the brachiocephalic artery.It begins in the neck behind the right sternoclavicular joint. Left common carotid artery is a branch of the arch of aorta.It ascends to the back of the left sternoclavicular joint and enters the neck. In the neck,each artery runs upwards within the carotid sheath,under cover of the anterior border of the sternocleidomastoid muscle. COMMON CAROTID ARTERIES

8. Carotid sheath is condensation of the fibroareolar tissue around the main vessels of the neck. CONTENTS: It contains the common and internal carotid arteries,internal jugular vein and the vagus nerve. In the sheath,common carotid artery is medially placed.Vagus nerve lies in between. CAROTID SHEATH

9. The ansa cervicalis lies embedded in the anterior wall of the carotid sheath. The cervical sympathetic chain lies behind the sheath . RELATIONS

10. Common carotid artery bifurcates into external and inter n al carotid arteries at t he level of upper border of t he thyroid cartilage. Two structures of importa nce at the bifurcation are Carotid sinus Carotid body BIFURCATION OF COMMON CAROTID ARTERY

11. This bifurcation can sometimes be at a higher or lower level artery may be compressed against the prominent transverse process of the sixth cervical vertebra ( Chassaignac’s tubercle); above this level it is superficial and its pulsation can be easily felt.

12. APPLIED ANATOMY Hypoglossal nerve is in closer proximity to the CCA bifurcation when the CCA bifurcates at the level of the body of hyoid, than when the CCA bifurcates at the superior border of thyroid cartilage. Thus, the presence of a high CCA bifurcation should caution surgeons that the hypoglossal nerve is more vulnerable. Kim T, Chung S, Lanzino G. Carotid artery–hypoglossal nerve relationships in the neck: an anatomical work. Neurological Research. 2009;31(9):895–9.

13. Carotid sinus is slight dilatation at the termination of the common carotid artery or the beginning of the internal carotid artery. It receives a rich innervation from the glossopharyngeal and sympathetic nerves. FUNCTION: Carotid sinus acts as a baroreceptor or pressure receptor and regulates pressure. CAROTID SINUS

14. Carotid body is a small,oval reddish-brown structure situated behind the bifurcation. It receives nerve supply mainly from the glossopharyngeal nerve, but also from the vagus and sympathetic nerves. FUNCTION: Carotid body acts as a chemoreceptor and responds to changes in the oxygen and carbon dioxide and Ph content of the blood . CAROTID BODY

15. EXTERNAL CAROTID ARTERY

16. SURFACE MARKING Palpation of common carotid artery: Draw a line from mastoid process to sternoclavicular joint. Then draw a horizontal line from upper border of thyroid cartilage. The point where these two lines meet is the site of bifurcation of common carotid artery. This artery should be palpated just below this point. Absent carotid artery pulsation is called a Berry sign

17. ECA begins in the carotid triangle at the level of upper border of thyriod cartilage opposite the disc between the third and fourth cervical vertibrae . COURSE

18. In the carotid triangle,it lies under cover of the anterior border of the sternocleidomastiod muscle As the artery ascends ,it passes deep to the post. Belly of digastric and stylohyoid muscle and terminates behind the mandible by dividing into the maxillary and superficial temporal arteries.

19. BRANCHES ANTERIOR Superior thyroid Lingual Facial POSTERIOR Posterior auricular Occipital MEDIAL Ascending pharyngeal TERMINAL Superficial temporal Maxillary

20. The variations in the branching pattern of ECA were reported in the literature. Zumre et al., in his study on variations of branches of ECA described a linguofacial trunk in 20% of the cases, a thyrolingual trunk in 2.5%, a thyrolinguofacial trunk in 2.5%, and an occipitoauricular trunk in 12.5% of the cases ( Zumre 2005) Gurbuz et al found carotid trifurcation during routine dissection.

21. APPLIED ANATOMY The carotid sinus syndrome (CSS) is characterized by syncope and hypotension due to a hypersensitive carotid sinus located in the carotid bifurcation. While supporting the mandible care should be taken not to apply pressure on the carotid sinus

22. SUPERIOR THYROID ARTERY First branch of the external carotid artery, Below the level of the greater cornua of the hyoid bone origin of the superior thyroid artery appeared to be related to the level of the CCA bifurcation. If carotid artery had a relatively low bifurcation, the superior thyroid artery tended to originate from the ECA. when the CCA had a high bifurcation, the superior thyroid artery tended to originate at the level of the carotid bifurcation. Lo A, Oehley M, Bartlett A, Adams D, Blyth P, Al-Ali S. Anatomical Variations Of The Common Carotid Artery Bifurcation. ANZ Journal of Surgery. 2006;76(11):970–2

23. ORIGIN: Arises from the front of ECA below the tip of greater cornua of hyoid bone . COURSE: Runs downwards and forwards parallel and just superficial to the extenal laryngeal nerve. - It passes deep to omohyoid ,sternohyoid, sternothyroid and reaches the upper pole of lateral lobe of thyroid and divides into its terminal branches. It is accompanied by same-named vein.

24. BRANCHES INFRAHYOID ARTERY : A small vessel, passing inferior to the hyoid bone to anastomose with its counterpart on the other side. -Supplies infrahyiod muscles. STERNOCLEIDOMASTOID ARTERY :Passes ventral to the carotid sheath, suppling SCM on its deep surface. SUPERIOR LARYNGEAL ARTERY : Passes superficial to the inferior pharyngeal constrictor muscle and pierces the thyrohyoid membrane, accompanied by the internal laryngeal nerve. -Within the larynx, it serves its muscles, glands, and mucosa.

25. CRICOTHYROID ARTERY: Supplies cricothyriod muscle and anastomoses with the artery of the opposite side. GLANDULAR BRANCHES Supplies the upper one third of the lobe and the upper half of the isthmus. Anterior branch Posterior branch Lateral branches(occasionally). The anterior branch descends on the anterior border of the lobe and continues along the upper border of the isthmus to anastomose with the opposite side.

26. APPLIED ANATOMY The artery and external laryngeal nerve are close to each other higher up, but diverge slightly near the gland. ligature of superior thyroid artery in thyroid surgery should be made close to the gland in order to avoid injury of the external laryngeal nerve. Damage to the external laryngeal nerve causes some weakness of phonation due to loss of tightening effect of the cricothyriod on the vocal cord. Alzahrani RE, Alashkham A, Soames R (2018) Observations on the Superior Thyroid Artery and its Relationship with the External Laryngeal Nerve. Anat Physiol 8: 292.

27. ORIGIN: Arises from ECA opposite the tip of the greater cornua of hyoid bone. -It may arise in common with the facial artery, then becoming the linguofacial trunk. COURSE: Divided into three parts by hyoglossus muscle. FIRST PART – In carotid triangle, extends from origin to the posterior border of hyoglossus. - Rests on the middle constrictor,forms a upward loop which is crossed by hypoglossal nerve. This loop permits the free movements of the hyiod bone.

28. SECOND PART – Deep to hyoglossus, runs horizontally forward along the upper border of hyoid bone between hyoglossus laterally and middle constrictor , stylohyoid ligament medially.

29. THIRD PART Also called as deep lingual artery. -It runs upwards along the anterior Border of hyoglossus, then horizontally forwards on the undersurface of tongue on each side of frenum linguae. -In vertical course,it lies b/t the genioglossus medially & inferior longitudinal muscle of tongue laterally. Horizontal part is accompanied by lingual nerve.

30. Has four branches: SUPRAHYOID ARTERY : Courses along the superior border of the hyoid bone, serving the muscles in its vicinity, and anastomosing with its counterpart on the other side. DORSAL LINGUAL ARTERY: Arises deep to the hyoglossus muscle. It ascends to the posterior dorsum of the tongue to supply the palatoglossal arch, mucous membrane of the tongue, palatine tonsil, and some of the soft palate , freely anastomosing with other arteries in its vicinity. BRANCHES

31. SUBLINGUAL ARTERY : Arises at the border of the hyoglossus muscle to course between the genioglossus and mylohyoid muscles on its way to the sublingual gland , which it supplies along with adjacent muscles in addition to the mucous membrane of the floor of the mouth and gingiva . -Branches of this artery anastomose with the submental branch of the facial artery. DEEP LINGUAL ARTERY: Terminus of the lingual artery. -Passes along the ventral aspect of the tongue, immediately deep to the mucous membrane, accompanied by the lingual nerve, to its apex, where it will anastomose with its counterpart of the other side.

32. In surgical removal of tongue , first part of artery is ligated before it gives any branches to the tongue or tonsil. APPLIED ANANTOMY

33. Beclards triangle: posterior belly of the digastric muscle superiorly, the greater horn of the hyoid bone inferiorly, and the posterior border of the hyoglossus muscle posteriorly , with the floor being the hyoglossus muscle.

34. LESSER'S TRIANGLE; is bordered superiorly by the hypoglossal nerve and anteriorly and posteriorly by the intersection of the hypoglossal nerve with the anterior and posterior bellies of digastric muscle The floor consists of the mylohyoid and hyoglossus muscles.

35. Pirogoff's triangle is bordered superiorly by the hypoglossal nerve, posteriorly by the posterior belly of the digastric muscle anteriorly by the posterior border of the mylohyoid muscle The floor of this triangle being the hyoglossus muscle.

36. SUBLINGUAL ARTERY Injury occurs in premolar & molar region, when sharp instrument or rotating disks slips off a lower molar & injure the floor of mouth. -May present problems to the surgeon attempting to ligate its source because it may arise from the submental branch of the facial artery rather than from the lingual artery.

37. ORIGIN: Arises from the ECA just above the tip of greater cornua of hyoid bone. COURSE: Runs upwards in -- neck as cervical part ; face -- facial part. Tortuous course —In neck allows free movements of pharynx during deglutition, on face -- free movements of mandible , lips, & cheek during mastication & facial expressions, escapes traction & pressure during movements. .

38. Cervical part : Cervical part Runs upwards on superior constrictor of pharynx deep to the posterior belly of digastric. -It grooves the posterior border of submandibular gland, makes S-bend [2 loops] 1st winding down over submandibular gland & then up over the base of mandible.

39. Facial part: The vessel enters the face by winding around the base of the mandible, and by piercing the deep cervical fascia,at the anteroinferior angle of the masseter muscle. It runs upwards and forwards deep to the risorus, to a point 1.25cm lateral to the angle of the mouth. Then it ascends by the side of the nose upto the medial angle of the eye where it terminates by anastomosing with the dorsal nasal branch of the ophthalmic artery.

40. SURFACE MARKING OF FACIAL PART . By joining the following 3 points A point o n the base of the mandible at the anteriorinferior border of the masseter muscle. A second point 1.2cm lateral to the angle of the mouth. A point at the medial angle of the eye. 1 2 3

41. VARIATIONS : May arise in common with lingual artery constituting ―linguo-facial trunk‖. -Occasionly ends by forming submental artery and freqently extends only as high as the angle of mouth or nose. -Deficiency is compensated by enlargement of one of neighbouring arteries.

42. CERVICAL PART: ASCENDING PALATINE ARTERY: Originates near the origin of facial artery. -It passes upwards between the stylopharyngeus and styloglossus muscles, to supply the levator veli palatini, superior pharyngeal constrictor and neighboring muscles, soft palate, tonsils, and auditory tube. TONSILLAR A RTERY: Passes between the styloglossus and medial pterygoid muscles and pierces the superior pharyngeal constrictor muscle to supply the palatine tonsil and the posterior tongue. BRANCHES

43. GLANDULAR ARTERIES: Distribute as three or four vessels to the submandibular gland to supply it and the adjacent area. SUBMENTAL ARTERY: Arises from the facial artery near the anterior border of the masseter muscle. -It follows the base of the mandible in an anterior direction and turns onto the chin at the anterior border of the depressor anguli oris muscle and accompanies with the mylohyiod nerve. -It supplies the submental triangle and sublingual salivary gland and forms anastomoses with several arteries in its vicinity, including the mental and sublingual arteries.

44. FACIAL PART: INFERIOR LABIAL ARTERY: Originates near the corner of the mouth, passes deep to the depressor anguli oris muscle, and pierces the orbicularis oris muscle. -The artery courses superficial to that muscle, supplying it as well as the substance of the lower lip. -It forms an anastomosis with its counterpart of the other side and with branches of the mental and submental arteries.

45. SUPERIOR LABIAL ARTERY: Arises just above the inferior labial artery. It passes superficial to the orbicularis oris muscle in the upper lip to serve that muscle as well as the substance of the upper lip. - It sends a small twig, the SEPTAL BRANCH to supply anteroinferior part of the nasal septum and another one, the ALAR BRANCH , into the wing of the nose. -The terminus of the vessel will anastomose with its counterpart of the opposite side.

46. LATERAL NASAL ARTERY: Small branch arising at and passing into the wing and bridge of the nose. -This supplies ala and dorsum of the nose . This vessel will anastomose with various other arteries in its vicinity. ANGULAR ARTERY: Is the terminal continuation of the facial artery, supplying the tissues in the vicinity of the medial corner of the eye and anastomosing with dorsal nasal branch of the ophthalmic artery.

47. Facial Artery Comp r es s ion: Applying pressure to the facial artery as it passes over the inferior border of the mandible just anterior to the angle will diminish blood flow to that side. o Can be injured –during operative procedures on lower premolars & molars , if instrument enters the cheek at inferior vestibular fornix., also while attempt to open a buccal abscess or mucocoele. Applied anatomy

48. In mand. 1 st molar region care must be taken not to injure the facial artery while extending the vertical incision down the vestibule during surgical extraction of mandibular impaction So it is recommended t o start vertical incision from the ves t ibu l e in upward direc t ion. While excising the sbmandibular gland,the facial artery should be ligated at two points and should be s e cured before dividing it, otherwise it may retract through stylomandibular ligament causing serious bleeding.

49. Trauma to the facial artery should always be avoided as the clinician should refrain from excessive retraction in this area. Proximal ligation of facial artery must be accomplished along its course before it enters the deep aspect of submandibular gland and gives off its branches; glandular and submental arteries. Interruption of the facial artery flow by injury or during surgery is usually not significant since its zone of supply is rapidly taken over by transverse facial artery, buccal , infraorbital and sphenopalatine branches

50. Mathes DW, Furukawa M, Anzai Y. Abstract 132. Plastic and Reconstructive Surgery. 2013;131:100.

51. ORIGIN: Arises in carotid triangle from posterior aspect of ECA , opposite the origin of facial artery. -It is crossed at its origin by hypoglossal nerve. COURSE: Passes backwards and upwards along & under cover of lower border of post. Belly of diagastric , crossing carotid sheath, hypoglossal & accessory nerves. Then it runs deep to the mastiod process and muscles attached to it i.e.,sternocleidomastiod, digastric etc.

52. Then crosses the rectus capitus lateralis,superior oblique,and semispinalis capitus muscle at the apex of the posterior triangle. Finally it pierces the trapezius muscle and ascends in a tortuous course in the superficial fascia of the scalp. Its terminal portion comes to lie along the greater occipital nerve.

53. IN THE CAROTID TRIANGLE STERNOMASTOID BRANCHES – Two in no.,upper branch accompanies the accessory nerve and lower branch arises near the origin of the occipital artery. Supplies sternomastoid m uscle IN THE POSTERIOR TRIANGLE and SCALP REGION: AURICULAR BRANCH: Passes superficial to the mastoid process to reach and supply the back of the auricle. BRANCHES

54. MASTOID BRANCH:– Enters cranial cavity through mastoid foramen, supplies mastoid air cells MENINGEAL BRANCH – Ascends with the internal jugular vein and enters the skull through jugular foramen & condylar canal, supplies dura of posterior cranial fossa. MUSCULAR BRANCH -Supply the Digastricus, Stylohyoideus, Splenius, and Longissimus capitis.

55. DESCENDING BRANCH : The largest branch of the occipital, descends on the back of the neck, and divides into a superficial and deep portion. -The superficial portion runs beneath the Splenius, giving off branches which pierce that muscle to supply the Trapezius and anastomose with the ascending branch of the transverse cervical artery. -The deep portion runs down between the Semispinales capitis and colli, and anastomoses with the vertebral and with the a. profunda cervicalis, a branch of the costocervical trunk.

56. The terminal branches of the occipital artery (occipital branches ) are distributed to the back of the head: they are very tortuous, and lie between the integument and Occipitalis, anastomosing with the artery of the opposite side and with the posterior auricular and temporal arteries, and supplying the Occipitalis, the integument, and pericranium

57. APPLIED ANANTOMY Superficial branch anastomosis with ascending branch of transverse cervical artery. Deep branch of descending branch of occipital artery anastomosis with deep cervical artery.

58. ORIGIN: Arises from the posterior aspect of the external carotid artery just above the posterior belly of the digastric. COURSE: It runs upwards and backwards deep to parotid gland, but superficial to the styloid process.It crosses the base of the mastiod process and ascends behind the auricle. POSTERIOR AURICULAR ARTERY

59. Besides several small branches to the Digastricus, Stylohyoideus, and Sternocleidomastoideus, and to the parotid gland, this vessel gives off three branches: Stylo m as t oi d . Auricular Occipital. Stylomastoid Artery ( a. stylomastoidea ) :Enters the stylomastoid foramen along with facial nerve and supplies the tympanic cavity, the tympanic antrum and mastoid cells, and the semicircular canals . In the young subject a branch from this vessel forms, with the anterior tympanic artery from the internal maxillary, a vascular circle, which surrounds the tympanic membrane. BRANCHES

60. Auricular Branch ( ramus auricularis ): Ascends behind the ear, beneath the Auricularis posterior, and is distributed to the back of the auricle , upon which it ramifies minutely, some branches curving around the margin of the cartilage, others perforating it, to supply the anterior surface. -It anastomoses with the parietal and anterior auricular branches of the superficial temporal.

61. Occipital Branch ( ramus occipitalis ): Passes backward, over the Sternocleidomastoideus, to the scalp above and behind the ear. It supplies the Occipitalis and the scalp in this situation and anastomoses with the occipital artery.

62. ORIGIN: The smallest branch arising from the medial side of the external carotid artery, near its commencement. COURSE: Ascends vertically between the internal carotid and the side of the pharynx, to the under surface of the base of the skull, lying on the Longus capitis.

63. PHARYNGEAL BRANCHES :Are three or four in number. Descend to supply the medial and inferior constrictors of pharynx and the Stylopharyngeus . PALATINE BRANCH: It passes inward upon the superior constrictor of pharynx, sends ramifications to the soft palate and tonsil , and supplies a branch to the auditory tube. PREVERTEBRAL BRANCHES: Are numerous small vessels, which supply the Longi capitis and colli, the sympathetic trunk, the hypoglossal and vagus nerves, and the lymph glands . BRANCHES

64. INFERIOR TYMPANIC ARTERY : Passes through a minute foramen in the petrous portion of the temporal bone, in company with the tympanic branch of the glossopharyngeal nerve, to supply the medial wall of the tympanic cavity and anastomose with the other tympanic arteries. MENINGEAL BRANCHES: Are several small vessels, which supply the dura mater . One, the posterior meningeal, enters the cranium through the jugular foramen; a second passes through the foramen lacerum; and occasionally a third through the canal for the hypoglossal nerve.

65. APPLIED ANATOMY The ascending pharyngeal artery plays an important role in the healing process of Le Fort I osteotomies , because it supplies the attached posterior palatal soft-tissue pedicle Superselective microcatheter placement in various branches of the external carotid artery ,Specifically infusion of the ascending pharyngeal artery is necessary for successful embolization of cancer of the palate

66. ORIGIN: Large terminal branch given off behind the neck of the mandible. COURSE: Divided into three parts by lateral pterygiod muscle. The first or mandibular portion passes horizontally forward, between the ramus of the mandible and the sphenomandibular ligament, where it lies parallel to and a little below the auriculotemporal nerve; it crosses the inferior alveolar nerve, and runs along the lower border of the lateral pterygiod.

67. The second or pterygoid portion runs obliquely forward and upward superficial to the lower head of the lateral pterygiod. The third or pterygopalatine portion passes between the t wo heads of the l a t er a l pterygi o d and pterygomaxillary fissure,to enter into the pterygopalatine fossa where it lies in front of the sphenopalatine ganglion.

68. First or Mandibular Portion Deep Auricular. Anterior Tympanic. Middle Meningeal Accessory Meningeal Inferior Alveolar. Second or Pterygoid Portion Deep Temporal. Masseteric. Pterygoid. Buccinator. Third or Pterygopalatine Portion Posterior Superior Alveolar. Infraorbital. Greater palatine artery Pharyngeal. Aretry of pterygiod canal Sphenopalatine. BRANCHES

69. Applied anatomy The mandibular division of maxillary artery and its branches are vulnerable during surgical procedures such as condylectomy or transoral osteotomies of the ascending ramus The masseteric artery passes through the mandibular notch and may be damaged by joint injections or during coronoidectomy . The buccal artery is often cut by intraoral incisions along the anterior coronoid crest because artery swings anteriorly around the crest to penetrate and supply buccinator muscle Middle meningeal artery may be torn in temporal fracture or injuries may lead to separation of from the dura matter to the bone, followed by hemorrhage between them, trephening may be necessary to reduce cerebral compression

70. The incision for a palatine abscess arising from palate in relation to molars should never be placed in transverse direction but placed in antero -posterior direction.

71. During lefort I osteotomy: Greater palatine artery is easily injured during oteotomy of the medial or lateral maxillary sinus walls, pterygomaxillary dysjunction or during d o wn fracturing of maxilla The average distance from the piriform rim to the descending palatine artery was 35.4 mm, range is 31 to 42 mm. The average length of the greater palatine canal above the nasal floor was 10mm, range is 6 to 15 mm. The average distance between the pterygomaxillary fissure and the greater palatine foramen was 6.6mm

72. GUIDELINES TO AVOID INJURY: Oteotomy of lateral wall of maxillary sinus should extend just beyond the second molar. Osteotomy of medial wall of maxillary sinus should usually extend 30mm posterior to the piriform rim in females,in males it can be carried back to 35mm Because the descending palatine artery travels in an anterior- inferior direction as it enters the greater palatine canal ,injury can be prevented by closely adapting the cutting edge of the osteotome or the saw to the pterygomaxillary fissure.

73. LITTLE’S AREA or KIESSELBACH’S PLEXUS -Near the anteroinferior part or vestibule of the septum. -Contains anastomoses between Superior labial branch of facial artery Branch of sphenopalatine artery Anterior ethmoidal artery Greater palatine artery This is common site of bleeding from nose or epistaxis.

74. ORIGIN: The smaller of the two terminal branches of the external carotid, appears, to be the continuation of ECA. It begins in the substance of the parotid gland, behind the neck of the mandible. COURSE: It runs vertically upwards crossing over the root of the zygomatic process -about 5 cm. above this process it divides into two branches, a frontal and a parietal.

75. Relations. — As it crosses the zygomatic process, it is covered by the Auricularis anterior muscle, and by a dense fascia; it is crossed by the temporal and zygomatic branches of the facial nerve and one or two veins, and is accompanied by the auriculotemporal nerve, which lies immediately behind it.

76. Besides some twigs to the parotid gland, to the temporomandibular joint, and to the Masseter muscle, its branches are: Transverse Facial. Anterior Auricular. Middle Temporal. Frontal. Parietal BRANCHES

77. Parietal branch Frontal branch Middle temporal artery Transverse facial artery

78. Transverse Facial Artery : ORIGIN: From STA before it leaves parotid gland . COURSE : Running forward through the substance of the gland, it passes transversely across the side of the face, between the parotid duct and the lower border of the zygomatic arch. This vessel rests on the Masseter, and is accompanied by one or two branches of the facial nerve . SUPPLIES: The parotid gland and duct, the Masseter, and the integument, and anastomose with the external maxillary , masseteric, buccinator, and infraorbital arteries.

79. Middle Temporal Artery : Arises immediately above the zygomatic arch, and, perforating the temporal fascia, gives branches to the Temporalis , anastomosing with the deep temporal branches of the internal maxillary artery. - It occasionally gives off a zygomaticoorbital branch, which runs along the upper border of the zygomatic arch, between the two layers of the temporal fascia, to the lateral angle of the orbit. -This branch, which may arise directly from the superficial temporal artery, supplies the Orbicularis oculi, and anastomoses with the lacrimal and palpebral branches of the ophthalmic artery.

80. Anterior Auricular Branches : Distributed to the anterior portion of the auricle, the lobule, and part of the external meatus, anastomosin g with the posterior auricular.

81. Frontal Branch : Runs tortuously upward and forward to the forehead, supplying the muscles, integument, and pericranium in this region, and anastomosing with the supraorbital and frontal arteries. Parietal Branch : Larger than the frontal, curves upward and backward on the side of the head, lying superficial to the temporal fascia, and anastomosing with its fellow of the opposite side, and with the posterior auricular and occipital arteries.

82. Applied Anatomy During the preauricular approach to condylar surgery, superficial temporal artery is identified along with the accompanying auriculotemporal nerve and retracted and tied Crossing the zygomatic process the artery is palpable through skin and fascia and is easily compressed here to control temporal hemorrhage

83. Thyroid gland tumors :- Malignant thyroid are highly vascular. Role of superior thyroid artery in superselective intra-arterial chemotherapy . Role in hyperthyroidism :- The mechanism is to block most of the blood supply to the thyroid gland, thus leading to necrosis and later fibrosis of thyroid tissue which will decrease thyroid hormone secretion. Embolisation of both the superior and one inferior thyroid artery will destroy 70- 80 % of gland achieving similar results to subtotal thyroidectomy .

84. LIGATION OF EXTERNAL CAROTID ARTERY The first recorded ligation of a common carotid artery was performed by Ambroise Paré in 1551.

85. INDIC A TION S Un c o n t r o lled hemorrhage Acu t e mass i v e ep i s t a x is He r ed i t a r y t elian g ect i a s is Nasopharyn g eal angi of i b r o m a Aneu r y sm s ( t r aum a tic aneu r y sms , o f hea d and neck , pa r ot id gland) Arteriovenous malformations Hyper vascular tumor (nasopharyngeal tumor, hemangiomas )

86. Exposed at two sites in the carotid triangle -at its origin from the common carotid (above the origin of superior thyroid artery) in the retromanibular fossa - here we ligate it behind the angle of mandible

87. IN THE CAROTID TRIANGLE INCISION A submandibular skin crease incision is made approximately two finger breadth below the angle of mandible extending from the inferior to the mastoid process to just short of midline (behind the anterior border of sternocledomastoid process) continue downwards / to the anterior border up to the level of cricoid cartilage after penetrating skin, platysma superficial sheath of sternoclediomastoid is incised exposure of great vessel with blunt dissection anterior border is exposed, muscle is retracted and deep layer is seen in this part internal juglar vein is exposed

88. the jugular vein is mobilized by opening the carotid sheath & free the jugular vein. retract posteriorly the vein to visualize artery as the dissection proceed posteriorly the carotid bulb is identified and bifurcation is seen manipulation of bulb at this stage may lead to arrythemia and anaesthesist should be informed external carotid artery is identified & ligated above the superior thyroid artery

89. COMPLICATIONS hameorrhage due to IJV or ECA ( profuse bleeding) damage to vagus nerve ( posteriomedially ) ligation of ICA ( contra lateral hemiplegia & blindness on the same side) hematoma formation /infection

90. IN RETROMANDIBULAR FOSSA ADVANTAGES: simpler less dangerous procedure artery is ligated in the retromandibular fossa behind the angle of mandible & here artery crosses the stylomandibular ligament at lateral side

91. INCISION incision starts the tip of mastoid process and circling the mandibular angle, continuing forward below the mandible for about one inch incision should be at equal distance from the posterior and inferior border of mandible exposure after the blunt dissection of skin, some post. fibers of platysma , retromandibular vein or ejv is located, cut & tied branches of greater auricular nerve is cut & tied to permit the mobilization of cervical lobe of parotid gland attachment of parotid with sternomastoid at anterior border is severed & gland is retracted anteriorly & upwards

92. underneath the parotid gland & post. belly of digastric, small thin part of stylohyoid muscle is visible above this- styloid process & stylomandibular ligament is palpated now moving the jaw forward entrance to retromandibular fossa is widened & pulse of eca is felt, isolate & ligate it

93. LIGATION OF LINGUAL ARTERY INCISION incision given below the lower border of mandible after palpating the submandibular gland the posterior part of incision should be towards the tip of mastoid process and anterior should point towards the chin after blunt dissection submandibular gland is exposed post belly of digastrics identified, mylohyoid muscle reached, hypoglossal nerve and accompanying vein identified

94. digastrics tendon pulled downward , hyoglossus muscle dissected and lingual artery is found and ligated

95. LIGATION OF FACIAL ARTERY INCISION ½ inch below & parallel to the lower border of mandible EXPOSURE the skin, platysma muscle and deep facia are cut, soft tissue is bluntly cut and retracted

96. Approach to facial artery- Incision is made at least ½ inch below lower border of mandible and parallel to it Skin – platysma and deep fascia are cut Blunt dissection done to reflect soft tissue upward Use finger to feel facial pulsation. Artery can be isolated, tied and cut. facial artery crosses the level of inferior vestibular fornix in the region of 1st mandibular molar avoid deep incision, incision should be downwards & inwards instead of straight upwards

97. LIGATION OF MAXILLARY ARTERY Approaches: 1. Trans- antral approach 2. Intraoral approach

98. Transantral ligation of IMA Traditional Caldwell-Luc approach Approximately 1-2cm of the posterior maxillary wall is removed to gain access to the pterygomaxillary fossa . The internal maxillary artery and collaterals are then identified with the operating microscope Surgical clips are placed on the proximal portion of the maxillary artery followed by descending palatine artery and sphenopalatine artery. Tackeno S;Transantral ligation of maxillary artery for refractory epistaxis : a case report; Hiroshima J Med Sci,Vol 40,No.3.109-113,Sept 1991

99. Intra oral approach for Maxillary artery ligation- Incision- extends posterior to the maxillary tuberosity or further to the anterior border of the ascending ramus of the mandible. Partial division of the anterior part of the insertion of masseter muscle on the zygoma is made IMA can be easily seen after blunt dissection of the buccal part of fat pad because most of the IMA lies lateral to the lateral pterygoid muscle.

100. LIGATION OF SPHENOPALANTINE ARTERY TWO METHODS 1. Transantral ligation 2. Endoscopic ligation

101. TRANSANTRAL APPROACH described by simpson et al. in 1982 approach C aldwell luc avoid entrance to pterygopalatine fossa medial, posterior & inferior wall is removed sphenopalatine & vidian nerve is dissected & ligation of artery is done

102. ENDOSCOPIC LIGATION described by White ( modification of simpsons tech) approach through 1. meatal antrostomy & 2. canine fossa not used widely advantages 1. reduce patient discomfort and 2. duration of hospitalization

103. EXTERNAL CAROTID ARTERY EMBOLIZATION PURPOSE: to occlude blood vessels proximal to the lesion to deposit intra- lesional micro-particulate substances deep within the capillary network.

104. CONCLUSION External carotid artery through its branches supplies the structures of head and neck region The knowledge of vascular anatomy of external carotid artery is essential while performing surgical procedures. Awareness of details and the topographic anatomy of variations of the external carotid may be useful for surgeons to prevent diagnostic errors, influence surgical tactics and interventional procedures and avoid complications during surgery in the cervical region.

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