Ligation Of External Carotid Artery

Attachment of parotid capsule to the anterior border of sternomastoid severed with scalpel. Parotid gland retracted .

post. Belly of digastric ,stylohyoid muscle is visible. Above this stylomandibular ligament can be palpated if lower jaw of the patient is pulled forward.

This movement--- widens the entrance into retromandibular fossa , tenses the stylomandibular ligament.

Pulsations of ECA are felt , isolated & tied.

• 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.

Lingual Artery

Applied Anatomy

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

 LIGATION OF LINGUAL ARTERY :

Incision – circling the lower pole of submandibular gland.

- Skin, platysma, deep fascia incised, submandibular gland exposed , lifted, tendon of diagastric visible.

-Free border of mylohyoid muscle seen, hypoglossal nerve identified. Digastric tendon pulled downwards –enlarges the lingual triangle, hyoglossus muscle visible.

- Muscle divided bluntly, in the gap of its vertical fibers lingual artery found & ligated.

• COURSE -

Divided into three parts by hypoglossus muscle.

• FIRST PART – In carotid triangle, extends from origin to the posterior border of hyoglossus.

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

• THIRD PART [ ‘arteria profunda linguae’ ]—Also called as deep lingual artery.

LIGATION OF EXTERNAL CAROTID ARTERY

• Ligation Of Facial Artery

• Ligation Of Lingual Artery

• Ligation Of External Carotid Artery
• In Carotid Triangle
• In Retromandibular Fossa

Branches

Total of 8 branches -

• ANTERIOR— Superior thyroid

Lingual

Facial

• POSTERIOR-- Occipital

Posterior auricular

• MEDIAL — Ascending pharyngeal
• TERMINAL— Maxillary

Superficial temporal

SURFACE MARKING

ECA is marked by joining the following two points.

-A) point on the anterior border of the sternocleidomastoid muscle at the level of the upper border of the thyroid cartilage.

-B) second point on the posterior border of the neck of the mandible.

The artery is slightly convex forwards in its lower half and slightly concave forwards in its upper half.

External Carotid Artery & Course

Generally,it lies anterior to the internal carotid artery.

It is the chief artery of supply to structures in the front of the neck and in the face.

Course

• 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.
• 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 neck of the mandible by dividing into the maxillary and superficial temporal arteries.

BIFURCATION OF COMMON CAROTID ARTERY

CAROTID BODY

• 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.

• Common carotid artery bifurcates into external and internal carotid arteries at the level of upper border of the thyroid cartilage.
• Two structures of importance at the bifurcation are

Carotid sinus

Carotid body

CAROTID SINUS

• 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 SHEATH

RELATIONS

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

• 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.

Applied Anatomy

LIGATION OF FACIAL ARTERY.

Exposed --at the point crossing the lower border of mandible .

Using contracted masseter as a landmark, pulse of facial artery felt at point situated anterior to the attachment of masseter.

Incision - at least half inch below the border of mandible & parallel to it.

ORIGIN: Arises from the ECA just above the tip of greater cornua of hyoid bone.

FACIAL ARTERY

COURSE: Runs upwards in -- neck as cervical part ; face -- facial part.

Tortuous course—rseIn 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.

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.

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.

Ligation of External Carotid Artery

Ligation

Incision of skin at level of angle , behind anterior border of SCM, downwards parallel to the anterior border of the muscle to the level of cricoid.

THERE ARE TWO SURGICAL EXPOSURES TO LIGATE THE ECA

CAROTID TRIANGLE

RETROMANDIBULAR FOSSA

Dissection is carried through skin,platysma,then anterior border of SCM is identified and retracted posteriorly.

A clamp is used to dissect anterior to the muscle parallel to great vessels ,to identify carotid sheath.

The CCA is carefully separated from other contents of sheath.

The IJV, vagus nerve and ansa hypoglossi are retracted posteriorly.

COMPLICATIONS:

-Damage to vital structures.

-Retrograde thrombus formation.

-Persistence of bleeding due to collateral flow.

• Usually at this place,a vesicular loop is placed loosely around CCA to obtain control.

• Then dissection is carried up along the CCA to the bifurcation area.

• At this point hypoglossal nerve is identified crossing the branches,it should be preserved.

ABOVE THE CAROTID TRIANGLE

Lies deep in the substance of the parotid triangle.

Within the gland, it is related

Superficially—Retromandibular vein

Facial nerve

Deep to the artery—ICA

Structures passing between ECA and ICA

Styloglossus

Stylopharyngeus

IXth nerve

Pharyngeal branch of

Xth nerve

Styloid process

EMBRYOLOGY OF ECA

Relation

CAROTID TRIANGLE

Superficially— Cervical branch of facial nerve

Hypoglossal nerve

Facial,lingual,and superior

Thyriod veins

Deep to the artery— Wall of pharynx

Superior laryngeal nerve

Ascending pharyngeal artery

LIGATION IN RETROMANDIBULAR FOSSA:

Done when there are maxillary artery injuries.

Skin incision--- at line starting at the tip of mastoid process , circling the mandibular angle, continuing forward below the mandible one inch.

Skin & posterior fibers of platysma are cut, the retromandibular vein or EJV is located, tied & cut.

Branches of great auricular nerve cut -- permit mobilization of cervical lobe of parotid gland.  

During the fourth and fifth weeks 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.

In the initial stage there are pairs of aortic arches, which are numbered I, II, III, IV, and V. This system becomes altered in further development.

• 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.

INTRODUCTION

Ligation Of External Carotid Artery

External carotid artery is the chief artery which supplies to structures in the front of the neck and in the face.

Refrences

1. Sicher

2. Gray's Anatomy

3. Peterson's

Thank You!

Presented By- Dr. Ashish Chalana

First Year PG