For medical undergraduates, nursing and physiotherapy students

1. ANTERIOR TRIANGLE
OF NECK – I
DR. SUNDIP CHARMODE
ASSOCIATE PROFESSOR
DEPARTMENT OF ANATOMY
AIIMS RAJKOT

3. BOUNDARIES
• In front: Anterior Median line from S. Mentis to
suprasternal notch
• Behind: Anterior border of the Sterno-cleido-mastoid
• Base: Lower border or Base of the Body of mandible
and a line extending from angle of mandible to
mastoid process
• Apex: Directed below and is formed by supra-sternal
notch

4. BOUNDARIES
• Roof:
1. Skin, Superficial Fascia,
2. Platysma
3. Investing layer of deep cervical fascia
4. Cervical branch of facial nerve
5. Ascending and descending branches of
Transverse cervical cutaneous nerve

6. SUB-DIVISIONS
• Each Anterior triangle is subdivided into :
1. Muscular triangle
2. Carotid triangle
3. Digastric triangle
4. Sub-mental – half triangle

7. MUSCULAR TRIANGLE
Boundaries
• In front: Anterior median line extending from
Hyoid bone to the supra-sternal notch.
• Behind and above: Superior belly of Omohyoid
• Behind and below: Anterior border of lower part
of sterno-cleido-mastoid
• Floor: Sterno-hyoid and Sterno-thyroid

9. CONTENTS
• No significant structures
• Beneath the floor, lies
1. Thyroid Gland,
2. Larynx,
3. Trachea,
4. Esophagus.

12. CAROTID TRIANGLE
Boundaries
• In front and above:
• Posterior belly of Digastric and Stylohyoid
• In front and below:
• Superior belly of Omohyoid
• Behind: Anterior border of sterno-cleido-
mastoid muscle.

15. CAROTID TRIANGLE
Boundaries
• Floor: Formed by parts of four muscles
1. Thyro-hyoid
2. Hyo-glossus
3. Inferior constrictor
4. Middle constrictor

16. FLOOR OF CAROTID TRIANGLE

18. CONTENTS
• Arteries
• Veins
• Nerves
• Other structures

19. ARTERIES
• Common Carotid artery and its two terminal
branches :
1. Internal carotid artery
2. External carotid artery

20. COMMON CAROTID ARTERY
• Origin
• Course

21. COMMON CAROTID ARTERY - RELATIONS
• In front and laterally:
– Skin
– Superficial fascia, Platysma, investing layer of deep
fascia
– Sterno-mastoid, Sternohyoid, Sternothyroid
– Descendens hypoglossi and ansa cervicalis
(embedded in the anterior wall of carotid sheath)

23. COMMON CAROTID ARTERY
• In behind:
– Transverse process of lower four cervical vertebrae
– Pre-vertebral muscles covered by pre-vertebral
fascia
– Sympathetic trunk
– Vertebral vessels below the carotid tubercle in
scaleno-vertebral triangle
– Carotid body at its bifurcation
• Laterally:
– Internal jugular vein with vagus nerve between and
behind them

25. COMMON CAROTID ARTERY
• Medially:
– Trachea, esophagus, recurrent laryngeal nerve
– Larynx and pharynx
– Thyroid gland
• Branches:

27. STRUCTURES BETWEEN ICA & ECA
1. A part of parotid gland
2. Styloid process of temporal bone
3. Styloglossus and stylopharyngeus muscles
4. Glossopharyngeal nerve
5. Pharyngeal branch of Vagus nerve

28. INTERNAL CAROTID ARTERY
• Supplies:
1. Cerebral hemispheres
2. Eyes
3. Contents of orbits
4. Forehead

29. EXTERNAL CAROTID ARTERY
• Origin :
• Course :

30. RELATIONS
• Superficial:
In Carotid Triangle-
• Overlapped by Sterno-cleido-mastoid
• Crossed by hypoglossal nerve, lingual and facial
veins
• Posterior belly of digastric, stylohyoid muscle
Within Parotid gland-
Overlapped by Retro-mandibular vein, facial nerve and
its branches

32. RELATIONS
• Deep:
• Constrictor muscles of pharynx
• Superior laryngeal nerve and its branches:
• Internal laryngeal nerve
• External laryngeal nerve
• Internal carotid artery

34. BRANCHES
• Medial side (1) : Ascending pharyngeal
• Front (3) : Superior thyroid, Facial, Lingual
• Behind (2) : Occipital, Posterior auricular
• Terminal (2) : Superficial temporal, Maxillary

35. ASCENDING PHARYNGEAL ARTERY
• First and smallest branch
• Arises from medial side and ascends to the base of
skull
• Lies between the wall of pharynx and ICA
BRANCHES
1. Pharyngeal branches
2. Inferior Tympanic branches
3. Meningeal branches

36. ASCENDING PHARYNGEAL ARTERY -
DISTRIBUTION
1. Pharyngeal branches – wall of pharynx, tonsils, part
of auditory tube and soft palate
2. Inferior Tympanic branches – medial wall of
tympanic cavity
3. Meningeal branches – dura mater and adjacent
bones, enter cranium through foramen lacerum,
jugular foramen and hypoglossal canal.

39. SUPERIOR THYROID ARTERY
• Arises from front, below the tip of greater cornua of
hyoid bone
• Pass down and forwards
• Accompanied by External laryngeal nerve (postero-
medial to it)
• Lies on Inf. Constrictor. Deep to OH,SH,ST muscles.
• Reach upper pole of thyroid gland. Lie superficial to
gland and divide into terminal branches.

43. SUPERIOR THYROID ARTERY - BRANCHES
1. Infra-hyoid branch
2. Superior Laryngeal
3. Crico-thyroid branch
4. Sternomastoid branch
5. Glandular branches –
1. Anterior
2. Posterior
3. Lateral

44. SUPERIOR THYROID ARTERY - DISTRIBUTION
1. Infra-hyoid:
– Anastomose with opposite artery across median plane along
lower border of hyoid bone
2. Superior Laryngeal:
– Pierces thyro-hyoid membrane along with Internal laryngeal
nerve.
– Supply larynx
– Anastomose with Inferior laryngeal branch of Inferior thyroid
artery
3. Crico-thyroid:
– Pass across Crico-thyroid ligament
– Anastomose with fellow branch

45. SUPERIOR THYROID ARTERY - DISTRIBUTION
4. Sternomastoid branch:
– Pass down and back
– Supply SCM
5. Glandular branches:
1. Anterior
2. Posterior
3. Lateral

46. LINGUAL ARTERY
• Arises from front of ECA, opposite to tip of greater
cornua
• Course divided into 3 parts by Hyoglossus muscle
• First part –
– Lies in carotid triangle
– From the origin to posterior border of hyoglossus
– Rests on middle constrictor
– Crossed superficially by hypoglossal nerve

47. LINGUAL ARTERY
• Second part –
– Lies deep to hyoglossus
– Runs horizontally forwards along the upper border of hyoid
– Lies between hyoglossus laterally and middle constrictor and
stylohyoid medially
– Artery is separated from hypoglossal nerve and vena
comitantes by hyoglossus.

48. LINGUAL ARTERY
• Third part –
– Ascends along the anterior border of hyoglossus
– Runs forwards beneath the mucus membrane of
undersurface of tongue
– Lies between longitudinalis linguae laterally and
genioglossus medially
– Accompanied by lingual nerve
– At the tip of tongue it anastomoses with fellow branch.

51. LINGUAL ARTERY - BRANCHES
• First part – Suprahyoid artery:
– Pass forward, along upper border of hyoid
– Anastomose with fellow artery across middle line
• Second part – Dorsal lingual arteries (3-4 branches):
– Supplies mucous membrane of dorsal surface of
tongue, palatine tonsils, soft palate
• Third part/Arteria Profunda Linguae – Sub-lingual
artery:
– Supply sublingual gland
– Mucus membrane of floor of mouth and adjoining gums

55. FACIAL ARTERY
• Arises from front of ECA, just above the tip of greater
cornua
• Cervical part:
– Pass upward and forward deep to posterior belly of digastric &
stylohyoid
– Lodges in a groove at posterior end of submandibular gland
– Presents loop with upward convexity, rests on middle and
superior constrictor
– Pass down, forward between medial pterygoid and lateral surf.
SM gland
– Winds round the lower border of mandible at antero-inferior
angle of masseter by piercing investing layer.

56. FACIAL ARTERY – BRANCHES
• Cervical part:
1. Ascending palatine artery:
– Arises from proximal loop, ascends along pharyngeal wall
– Winds round upper border of superior constrictor
– Supplies soft palate, tonsils, wall of pharynx and auditory
tube
2. Tonsillar artery:
– Arises close to Ascending palatine artery
– Reaches the gland by piercing superior constrictor
3. Glandular branches (3-4): Submandibular gland

57. FACIAL ARTERY – BRANCHES
4. Sub-mental artery:
– Winds round lower border of mandible
– Lies on mylohyoid muscle
– Supply adjoining structures
– Anastomose with mylohyoid branch of Inferior alveolar
artery
– Few branches anastomose with mental and inferior labial
arteries

59. FACIAL ARTERY - BRANCHES
• Facial part:
1. Inferior labial
2. Superior labial
3. Lateral nasal artery

60. OCCIPITAL ARTERY
• Arises from posterior aspect of ECA, opposite the
origin of Facial artery.
• Pass backwards and upwards
• Along and undercover of posterior belly of digastric
• Pass superficial to the contents of carotid sheath and
hypoglossal and accessory nerves.
• Pass deep to SCM, Splenius capitis, longissimus capitis
• Pierces trapezius and appears tortuously in posterior
part of scalp.

61. OCCIPITAL ARTERY
• Lodges in a groove on medial side of mastoid bone
• Pierces trapezius and appears tortuously in posterior
part of scalp.

62. OCCIPITAL ARTERY
1. Sterno-mastoid branches (2)- sterno-cleido-mastoid
2. Mastoid – enters cranial cavity, supply mastoid air
cells and duramater
3. Meningeal – enters skull and supplies duramater
4. Muscular- adjoining muscles
5. Occasional auricular – cranial surface of auricle

63. OCCIPITAL ARTERY
6. Descending branch -
– Superficial branch – anastomose with superficial branch of
transverse cervical artery
– Deep branch – anastomose with deep cervical artery
7. Occipital branches – scalp up to vertex

64. POSTERIOR AURICULAR ARTERY
• Arises from posterior aspect of ECA above the occipital
artery
• Pass back and upward along the upper border of
posterior belly of digastric
• Reach interval between auricle and mastoid process
and divide into terminal branches.

65. POSTERIOR AURICULAR ARTERY
1. Stylo-mastoid artery:
– Enters stylomastoid foramen
– Supply facial nerve, tympanic cavity, mastoid air cells,
semicircular canals
2. Auricular branch:
– Cranial and lateral surface of auricle
3. Occipital branch:
– scalp above and behind the auricle

66. SUPERFICIAL TEMPORAL ARTERY
• Smaller terminal branch
• Arises within the parotid gland behind neck of
mandible
• Lies superficial to temporal fascia
• About 5 cm above arch, divides into anterior and
posterior branches.

68. SUPERFICIAL TEMPORAL ARTERY - BRANCHES
1. Transverse facial artery:
– arises within parotid gland
– Pass forward across the masseter between the zygomatic
arch and parotid duct
– Supplies parotid gland and duct, TM joint, masseter muscle
– Anastomoses with branches of facial artery
2. Anterior auricular branch: Lateral surface of auricle
and external acoustic meatus
3. Zygomatico-orbital artery: Reach lateral angle of orbit

69. SUPERFICIAL TEMPORAL ARTERY - BRANCHES
4. Middle temporal artery:
– Supply temporalis
– Anastomose with middle temporal branch of maxillary
artery
5. Anterior/Frontal branch: Muscles and skin of
frontal region
6. Posterior/Parietal branch: Anastomose with
posterior auricular and occipital arteries

70. MAXILLARY ARTERY
• Largest terminal branch

71. VEINS
• Internal Jugular vein – Extends from Base of skull to the
root of neck.
• Collects blood from :
– Brain
– Superficial part of face and neck
• Lies lateral to the Internal and external carotid arteries
• Overlapped by Anterior border of sternocleidomastoid.

72. VEINS
• Tributaries of Internal Jugular vein present in
carotid triangle are :
1. Superior thyroid vein
2. Lingual vein
3. Common facial vein
4. Pharyngeal vein
5. Occipital veins
• They follow the course of their corresponding
arteries

73. CAROTID SHEATH
• Tubular investment of deep cervical fascia extends
from base of skull to arch of aorta containing:
– Common carotid artery (medial)
– Internal carotid artery (medial)
– Internal jugular vein (lateral)
– Vagus nerve (in between)
• Feltwork of condensed areolar tissue

75. CAROTID SHEATH
• Thick: arteries, Thin/ill-defined: veins ?
• Anterior wall:
– Pre-tracheal fascia
– Ansa cervicalis embedded in it
– Attached to deep surface of SCM, fused with pre-tracheal
fascia
• Posterior wall:
– pre-vertebral fascia
– Separated from pre-vertebral fascia by loose areolar tissue
– Cervical part of sympathetic chain passes between PVF and
PWOCS

76. STRUCTURES PEIRCING CAROTID
SHEATH
• External carotid artery
• (Most of the tributaries) of Internal jugular
vein
• Glossopharyngeal, accessory, hypoglossal and
cervical branches of Vagus nerves

77. NERVES
• A portion of Spinal part of Accessory nerve:
• Crosses the upper angle of carotid triangle
• Pass either superficial or deep to the Internal jugular
vein
• Disappears beneath or through sternocleidomastoid

79. LOOP OF HYPOGLOSSAL NERVE
• Winds around lower sterno-cleido-mastoid branch of
occipital artery
• Crosses superficial to ICA and ECA and the loop of 1st
part of lingual artery.
• The nerve gives 2 branches from the convex side of
the loop.

81. ANSA CERVICALIS

82. ANSA CERVICALIS
• Descendens hypoglossi:
– pass down in front of carotid sheath
– carries fibers of C1
• Forms a loop called as Ansa Cervicalis after joining
with the Descendens Cervicalis from C2 and C3.

84. NERVES
3. Vagus nerve: gives many branches as :
– Pharyngeal
– Superior laryngeal nerve
– Branch to carotid sinus and carotid body
– Superior and inferior cervical cardiac branches
– Right recurrent laryngeal nerve
• Sup. Laryngeal nerve will divide into :
1. External laryngeal nerve-
2. Internal laryngeal nerve –
4. Cervical part of Sympathetic trunk

86. NERVES
• Internal laryngeal nerve:
– Essentially sensory
– Pierces thyro-hyoid membrane
– Supply laryngeal mucous membrane till vocal cords
• External laryngeal nerve:
– Slender motor, accompanies Sup. Thyroid artery
– Motor branch to cricothyroid muscle
– Motor branch to inferior constrictor

88. OTHER STRUCTURES
• Apex of Parotid gland: encroaches on upper
angle of triangle.
• A chain of Deep Cervical Lymph nodes along
Internal jugular vein namely:
– Jugulo-digastric group – below posterior belly of
digastric
– Jugulo-omohyoid group – above superior belly of
omohyoid

90. CLINICAL CORRELATION
• In case of ligation of CCA, collateral circulation may
be established at:
a. Occipital anastomoses
b. Anastomoses around thyroid gland
c. Anastomoses across the middle line
• Ligation of Sup. Thyroid artery should be done close
to the gland.

91. CAROTID SINUS
• Fusiform dilatation present at the bifurcation of CCA
and the beginning of ICA.
• Wall of sinus is thinner and more elastic than the
adjacent part of the artery.
• Acts as baroreceptors for controlling intracranial blood
pressure
• Stimulation leads to reflex fall in blood pressure,
slowing of heart.

92. CAROTID SINUS
• Receives:
– Sinus branch from the glossopharyngeal nerve
– Twigs from Vagus nerve
– Sympathetic trunk
• Carotid sinus syndrome -

93. CAROTID BODY
• Small, oval neurovascular structure situated close to
the posterior wall of carotid sinus.
• Receives supply from:
– Glossopharyngeal
– Vagus
– Sympathetic nerves
• Acts as chemoreceptor monitoring oxygen tension
within the artery.

94. CAROTID BODY
• Stimulation of the
body by anoxia
produces:
o Reflex rise in blood
pressure and heart rate
o Changes in the depth
and rate of respiration.

95. CLINICAL CORRELATION
• Wry neck – deformity of neck caused due to shortening
of sternocleidomastoid
• Torticollis - repeated painful contractions of SCM and
trapezius of one side.
• Posterior belly of digastric:
– Key muscle of neck
– Vagus, accessory and hypoglossal nerves pass under it
– ICA, IJV and ECA pass under it

96. THANKS