Anatomy of the neck- divided into triangles. Relevant info for ENT and head and neck surgeons.

1. Dr. Juveria Majeed
MS ENT,
Govt. ENT Hospital/Osmania
Medical College
TRIANGLES OF NECK
1

2.  The side of the neck is roughly
quadrilateral in outline.
 It is bounded
 Anteriorly by –Anterior Median
Line
 Posteriorly- Anterior border of
Trapezius
 Superiorly- Base of the
Mandible, a line joining angle
of the mandible & mastoid
process, superior nuchal line.
 Inferiorly- Clavicle
 This quadrangular space is
divided obliquely by SCM
muscle into anterior and2

3. STERNOCLEIDOMASTOID
 Origin:
a) Sternal head
b) Clavicular head
 Insertion:
a) Lateral process of mastoid process
b) Lateral half of the superior nuchal line of occipital
bone
 Nerve Supply:
Spinal Accessory Nerve
 Blood Supply:
One br from sup thyroid A. and suprascapular A.
Two br from occipital A.
3

4. STERNOCLEIDOMASTOID
4
 One of the most
important landmark in
neck.
 Actions-
 When one muscles
contracts-
 When both muscles
contracts
 To make scm taut on
one side, the pt is
asked to turn the
head to opp. side
against resistance.

5. Layers of the Neck
5
 Skin
 Superficial fascia
 Deep fascia (Fascia Colli)
 Deep Structures
a) lying above the hyoid bone
b) lying below the hyoid bone

6. SKIN
6
 Loosely attached anteriorly.
 Posteriorly, the skin is very thick and adherent to
the underlying structures with numerous
sebaceous glands.
 Well supplied with blood vessels and has
transverse lines.
 Nerve supply: 2nd 3rd 4th cervical nerves.
 Anterolateral part: anterior primary rami thru ant.
cutaneous, great auricular, lesser occipital and
supraclavicular nerves.
 Posterior part supplied by dorsal posterior primary
rami.

7. Skin, subcutnaeous fat, superficial fascia containing
platysma, deep fascia
7

8. PLATYSMA
8
 It is a subcutaneous
muscle forming a
wide, thin fleshy sheet
running upwards and
medially in the neck
from deltoid and
pectoral fasciae to the
base of mandible.
 Supplied by cervical
br. of facial nerve.

9. DEEP FASCIA (FASCIA COLLI)
9
 Investing Layer
 Pretracheal Fascia
 Prevertebral fascia
 Carotid sheath
 Buccopharyngeal Fascia
 Pharyngobasilar Fascia

10. DEEP FASCIA
10

11. Anterior Triangle of Neck
11
 Boundaries:
Medially: Ant median plane of neck
Laterally: SCM
Superiorly: Base of the mandible and a line
joining the angle of the mandible n mastoid
process
 Subdivisions:
The ant triangle is subdivided by the digastric
belly and sup belly of omohyoid into:
a) Submental
b) Digastric
c) Carotid and
d) Muscular Triangles

12. ANTERIOR TRIANGLE -
SUBDIVISONS
12

13. 13

14. SUPRAHYOID MUSCLES14

15. SUPRAHYOID MUSCLES
15
MUSCLE ORIGIN INSERTION NERVE
SUPPLY
DIGASTRIC Anterior belly from
digastric fossa
Post belly from
mastoid notch
Intermediate
tendon held by a
pulley to hyoid
bone
Ant belly by nerve
of mylohyoid
Post belly by facial
nerve
STYLOHYOI
D
Posterior surface of
styloid process
Junction of body
and greater
cornua of hyoid
bone
Facial nerve
MYLOHYOID Mylohyoid line of
mandible
Body of hyoid
bone
Two m. muscle of
both side form
median raphe
Nerve to mylohyoid
GENIOHYOI
D
Inferior mental
spine(Genial
tubercle)
Ant surface of
body of hyoid
bone
C1 thru
hypoglossal nerve

16. SUBMENTAL TRIANGLE
16
 This is a median
triangle.
 Boundaries:
Either side- Anterior
belly of
corresponding
digastric muscles
Base- Body of hyoid
bone
Apex- at the chin
Floor- Rt and Lt
Mylohyoid muscle

17. CONTENTS OF SUBMENTAL
TRIANGLE
17
 It contains:
 one or two lymph glands,
the submental lymph
nodes
 some small veins; the
latter unite to form the
anterior jugular vein
 The lymph nodes of the
submental triangle
receive lymph from the
skin of the chin, the lower
lip, the floor of the mouth,
and the tip of the tongue.
They send lymph to the
submandibular and
jugular chains of nodes.
They belong to Level 1 gr
of LNs

18. DIGASTRIC TRIANGLE
18
 The submandibular
triangle (or submaxillary
or digastric triangle)
corresponds to the region
of the neck immediately
beneath the body of the
mandible.
 Boundaries:
Anteroinf: Ant belly of
digastric
Posteroinf: Post belly of
digastric and stylohyoid.
Superiorly: Base of the
mandible.
Roof : Skin, superficial
fascia with platysma
muscle, deep fascia

19. Floor of digastric triangle
19

20. CONTENTS OF DIGASTRIC
TRIANGLE
20
 ANTERIOR PART OF
TRIANGLE
 Strucures superficial to
mylohyoid are:Superficial
part of submandibular
gland, Facial vein ,
Subman. LN (belong to
Level 1 gr of LNs), Facial
A.,Submental A.,
Mylohyoid nerve and
vessels.
 Structures superficial to
hyoglossus:
Subman.gland,Intermedia
te tendon of digastric and

21. CONTENTS OF DIGASTRIC
TRIANGLE
21
 POSTERIOR PART
OF TRIANGLE:
 Superficial
Structures: Lower part
of parotid, ECA before
it enters parotid.
 Deep structures:
Styloglossus,
stylopharyngeus,
glossopharyngeal N,
Pharyngeal br of
vagus, Styloid process,
a part of parotid

22. CONTENTS OF POSTERIOR PART
OF DIGASTRIC TRIANGLE
22
 Deepest structures:
a) Internal carotid A.
b) Internal jugular vein
c) Vagus N.
• Submandibular LNs: Belong to Level 1 gr of LNs
• Clinically important because of their wide area of
drainage. They are very commonly enlarged.
• They drain: a) center of forehead
b) Nose with Max. Frontal & Ethmoid sinuses
c) Inner canthus of the eye
d) Upper lip and the ant part of cheek with adjoinin gums
e)Outer part of lower lip with gums and teeth excluding
incisors
f)Ant 2/3rd of tongue and floor of mouth

23. CAROTID TRIANGLE
23
 Boundaries:
 Anterosup: Post belly of
digastric
 Anteroinf: Sup belly of
omohyoid
 Posteriorly: Ant border of
SCM
 Roof: skin, superficial
fascia, investing layer of
deep fascia
 Floor: Thyrohyoid M,
hyoglossus, Middle and
Inf. constrictors of
pharynx

24. CONTENTS OF CAROTID
TRIANGLE
24
 ARTERIES:
 Common caortid A. with
carotid sinus and
carotid body at its
termination
 Internal carotid A.
 External carotid A. with
br.-
Ant br-sup thyroid, lingual
facial
Post br- Occipital , post.
Auricular
Medial- Asc. Pharyngeal
Terminal –Maxillary ,
Superficial Temporal.

25. CAROTID SINUS AND BODY
25

26. BRANCHES OF EXT.CAROTID
ARTERY
26

27. CONTENTS OF CAROTID
TRIANGLE
27
 VEINS:
 Internal Jugular V.
 Common Facial V.
 Pharyngeal V
 Lingual V. all draining
in to internal jugular
vein directly or via
facial vein

28. CONTENTS OF CAROTID
TRIANGLE
28
 NERVES:
 Vagus running vertically
downwards
 Sup L.N of vagus
dividing into ext n int
L.N
 Spinal Accessory N
 Hypoglossal N
 Sympathetic chain
 Carotid sheath and its
contents
 Lymph Nodes: Jugulo-
digastric and jugulo-
omohyoid

29. CONTENTS OF CAROTID
TRIANGLE
ACCESSORY N. HYPOGLOSSAL N.
29

30. ANSA CERVICALIS
30
 Also known as Ansa
Hypoglossi.
 This is a thin nerve
loop that lies
embedded in the ant
wall of carotid sheath.
 FORMATION:
Superior
Root:continuation of
descending br of
hypoglossal N.
Inferior Root: 2nd and 3rd
cervical spinal N.
• Supplies Infrahyoid
muscles.

31. MUSCULAR
TRIANGLE
31
 Also known as inferior
carotid triangle.
 Boundaries:
 Anteriorly: ant median
line of neck
 Posterosup: Sup belly of
omohyoid
 Posteroinf: Ant border od
SCM
Contents: Infra hyoid
Muscles are the chief
contents of this
triangle.They also form
the floor of the triangle

32. Infrahyoid / Strap / Ribbon
muscles32

33. INFRAHYOID MUSCLES
33
Muscle Origin Insertion Innervation
Sternohyoid Post surface
of manubrium
sterni
Medial part of
lower border of
hyoid bone
Ansa cervicalis
Sternothyr
oid
-Post surface
of manubrium
sterni
Oblique line on
lamina of
thyroid cartilage
Ansa cervicalis
Thyrohyoid Oblique line
on lamina of
thyroid
cartilage
Body and greater
cornua of hyoid
bone
C1 thru hypoglossal
N
Omohyoid
Sup and inf
bellies
Upper border
of scapula
near
suprasternal
notch
Lower border of
body of hyoid bone
Ansa cervicalis

34. POSTERIOR
TRIANGLE
34
 The boundaries are:
 Anterior: Post. Border of
SCM
 Posterior: ant border of
the trapezius muscle
(Fig. 1-21)
 Inferior or Base: Middle
1/3rd of clavicle
 Apex: Lies on the sup
nuchal line where scm
and trapezius meet.
 Roof: Investing layer of
the deep cervical fascia,
ext jugular vein

35. ROOF OF POSTERIOR
TRIANGLE35

36. FLOOR OF POSTERIOR
TRIANGLE36
 Floor: prevertebral
layer of deep cervical
fascia, covering
following muscles
a) Splenius capitus
muscle,
b) Levator scapulae
c) Scalenus medius
d) Occassionally
scalenus posterior

37. Subdivisions of posterior triangle
of neck
37
 Subdivided by inf.
belly of the omohyoid
into
a) Larger upper
triangle- Occipital
triangle
b) Smaller lower
triangle-
Supraclavicular or
Subclavian triangle

38. TRIANGLE
38
 Nerves
• Accessory nerve
• Root, trunks of brachial plexus and their branches :
Nerves to rhomboideus(dorsal scapular n)
Nerves to serratus anterior(long thoracic n)
Nerves to subclavius
Suprascapular nerve
 Cervical nerves
Greater occipital nerve
Great auriclular nerve
Lesser occipital nerve
Transverse cervical nerve of neck
Supraclavicular nerve
• 3rd and 4th cervical nerves supplying trapezius

39. NERVES OF POSTERIOR
TRIANGLE39

40. ARTERIES OF POSTERIOR
TRIANGLE
40
 Arteries
 Occipital artery
 Third part of
subclavianartery &
branches of
subclavianartery
 Suprascapular
 Transverse cervical

41. VEINS IN POSTERIOR TRIANGLE
41
 Lower part
of External
jugular vein
& its
tributaries
 Superficial
cervical
vein
 Subclavian
vein is
lower down
and not in
the triangle

42. LYMPH NODES OF POSTERIOR
TRIANGLE
42
 Supraclavicularl
ymph nodes are
present on
posteriorborder
of
sternocleidomas
toid
 Occipital nodes
 The nodes of
posterior
triangle belong
to 5th level of

43. Levels of lymph nodes
43
• Level I:
Ia-Submentalgroup
Ib-Submandibulargroup
 Level II:
around upper third of IJV &adjacent to SAN
IIa-located anteriorlyto SAN
IIb-located posteriorlyto SAN
 Level III:
around middle third of IJV
 Level IV: around lower third of IJV
 Level V (posterior triangle group):spinal accessory
nodes, nodes around transverse cervical vessels &
supraclavicular node
 Level VI: pre & paratracheal, precricoid & those around
reccurent laryngeal nerves
 Level VIII: Mediastinal Lymph nodes

44. 44

45. 45