The carotid triangle contains the carotid arteries, internal jugular vein, and cranial nerves X, XI, and XII. It is bounded by the posterior belly of the digastric muscle, the omohyoid muscle, and the anterior border of the sternocleidomastoid muscle. The carotid sheath surrounds the major blood vessels and nerves as they pass through the neck. The glossopharyngeal and vagus nerves pass through the carotid triangle, giving off branches innervating nearby structures before descending in the neck.

2. Carotid Triangle
Boundaries
Post. Belly of digastric m
sup. Belly of omohyoid
Ant. border of sternomastoid

3. Carotid Triangle
Contents
I. Carotid sheath
is a column of fascia that surrounds the blood
vessels and nerves as they pass through the neck

4. I. Carotid sheath
Attachment:
• Sup.: Base of skull
(Carotid and jugular
foramina)
• Inf.: Arch of aorta

5. I. Carotid sheath
Contents:
• Above post. Belly of
digastric: ICA, IJV &
lower 4 CNs
• Below post. Belly of
digastric: CCA, IJV
& vagus nerve

6. Carotid Triangle
Contents
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

7. Common Carotid a
Origin:
• Rt CCA: from innominate a
• Lt CCA: from arch of aorta

8. Common Carotid a
Termination: at C3-4 or at upper border of thyroid cartilage by dividing into 2
terminal branches ICA & ECA
Branches: ICA and ECA

9. Internal Carotid a
Origin: at C3-4 or at upper border of thyroid cartilage from CCA
Termination: intracranially by dividing into anterior and middle cerebral a

10. Internal Carotid a
Divide into parts : cervical, intrapetrous, intracavernous &
intracranial
• Termination of Cervical part: at carotid canal
• Branches of cervical part : NO BRANCHES

11. External Carotid a
Origin: at C3-4 or at upper border of thyroid
cartilage from CCA
Termination: in parotid g. by dividing into
superficial temporal a & maxillary a

13. External Carotid a
Branches: 6
3 ant
2 post
1 medial

14. 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

16. The Glossopharyngeal nerve
a.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

17. The Glossopharyngeal nerve
Course :
9th CN
•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 Stylopharyngeus
between the internal and
external carotid arteries

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

19. 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

20. The Vagus nerve
a.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

21. Vagus nerve 10th CN
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

22. Vagus nerve
Course :
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

23. Vagus nerve
Branches:
I. From sup. ganglion
Meningeal n
Auricular n
II. From inf. ganglion
Pharyngeal n (motor)
Superior laryngeal n (mixed)
III. Cardiac branch (parasym.)
IV. Recurrent laryngeal n (mixed)