CAROTID TRIANGLE

Carotid TriangleBoundaries Post. Belly of digastric m

sup. Belly of omohyoid

Ant. border of sternomastoid

Carotid TriangleContents

I. Carotid sheath

is a column of fascia that surrounds the blood vessels and nerves as they pass through the neck

I. Carotid sheath

Attachment:

• Sup.: Base of skull (Carotid and jugular foramina)

• Inf.: Arch of aorta

I. Carotid sheath

Contents:

• Above post. Belly of digastric: ICA, IJV & lower 4 CNs

• Below post. Belly of digastric: CCA, IJV & vagus nerve

Carotid TriangleContents

II. 3 Carotid arteries: CCA, ICA & ECA

III. IJV

IV. 10, 11 & 12 CN

V. 3 small nerves: descending hypoglossi & cervicalis & nerve to thyrohyoid

VI. Cervical lymph nodes

VII. Sympathetic chain

Common Carotid aOrigin:

• Rt CCA: from innominate a

• Lt CCA: from arch of aorta

Common Carotid aTermination: at C3-4 or at upper border of thyroid cartilage by dividing into 2 terminal branches ICA & ECA

Branches: ICA and ECA

Internal Carotid aOrigin: at C3-4 or at upper border of thyroid cartilage from CCA

Termination: intracranially by dividing into anterior and middle cerebral a

Internal Carotid aDivide into parts : cervical, intrapetrous, intracavernous & intracranial• Termination of Cervical part: at carotid canal

• Branches of cervical part : NO BRANCHES

External Carotid aOrigin: at C3-4 or at upper border of thyroid cartilage from CCA

Termination: in parotid g. by dividing into superficial temporal a & maxillary a

Branches: 63 ant2 post1 medial

External Carotid a

Internal jugular vein

Beginning: sigmoid venous sinus

Termination: join subclavian V to form innominate V

Has 2 dilatations (sup. & inf. Bulbs)

Tributaries:

1. Inf. Petrosal sinus

2. Pharyngeal V

3. Lingual V

4. Common facial V

5. Sup. Thyroidal V

6. Middle thyroidal V

CRANIAL NERVES 9TH & 10TH

The Glossopharyngeal nervea.Functions: mixed (motor, sensory & parasympathetic)b.Deep origin: in the medulla oblongata c.Foramen: middle of the jugular foramen e.Ganglia:

• Superior ganglion: small and has no branches • Inferior ganglion: large give tympanic branch

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The Glossopharyngeal nerve

Course : • At the base of the skull the

nerve lies between the internal jugular vein and the internal carotid artery deep to the styloid process and structures attached to it and the posterior belly of digastric

• Then leave carotid sheath & passes forward with stylopharyngeus muscle between the internal and external carotid arteries

9th CN

Stylopharyngeus

The Glossopharyngeal nerve

Course : then curves forwards between the superior and middle constrictor muscles of pharynx to end by breaking into its terminal branches

The Glossopharyngeal nerve

Branches:

Tympanic nerve: become the lesser petrosal nerve ……….otic ganglion. supplies the parotid gland

Carotid branch: to the carotid sinus and body,

Pharyngeal branches: sensory

Nerve to the stylopharyngeus

Tonsillar branches: sensory from the palate and the tonsils

Lingual branches: carry general and taste fibres from the posterior 1/3 of the tongue

The Vagus nervea.Functions: mixed (motor, sensory & parasympathetic)b.Deep origin: in the medulla oblongata c.Foramen: middle of the jugular foramen e.Ganglia:

• Superior ganglion: small give 2 branches• Inferior ganglion: large give 2 branches. Cranial accessory

root (XI) join it

Cranial part

of XI

Vagus nerveCourse : At the base of the skull the nerve lies between the internal jugular vein and the internal carotid artery deep to the styloid process and structures attached to it and the posterior belly of digastric

10th CN

Vagus nerveCourse : The nerve descends vertically within the carotid sheath between the common carotid artery and the internal jugular vein until it reaches the root of the neck, it crosses in front of the first part of the subclavian artery to the thorax

Vagus nerve

Branches:

I. From sup. ganglionMeningeal nAuricular n

II. From inf. ganglionPharyngeal n (motor)Superior laryngeal n (mixed)

III. Cardiac branch (parasym.)

IV. Recurrent laryngeal n (mixed)