1. 1

2. Introduction
• Surgeon should master surgical anatomy of the neck before
embarking on any neck dissection
• Upper border of the neck:
 ant: FOM
 post: BOS
• Lower border:
 ant: upper border of 1st rib
 post: body of the 1st thoracic vertebrae
2

3. Developmental Anatomy
• Skin of the neck – from cervical dermatomes (2nd to 6th cervical
segments)
• SCM, strap muscles and trapezius – cervical myotomes
• Six branchial arches form at four weeks of POG – has principal
nerve and vessel
• The first arch:





Form the upper border of the neck
Bone: mandible - derived from Meckel’s cartilage
Muscles: mylohyoid, ant. belly of digastric
Trematic nerve is the mandibular branch of the trigeminal nerve
The first pouch form ear structures only
3

4. • The second arch:
 Bone: Styloid process, lesser cornu and upper body of hyoid bone formed from Reichart’s cartilage
 Muscles: platysma, post belly of digastric and stylohyoid
 Nerve: Facial nerve
 The second pouch – ear related structures
• The third arch:





Bone: greater cornu and inferior body of the hyoid bone
Cartilage: epiglottis – developed from hypobranchial eminence
Muscle: stylopharyngeus
Nerve: glossopharyngeal nerve
The third pouch:
• ventral aspect – thymus
• posterior aspect - inferior parathyroid gland
4

5. •
•
•
•
Arches four, five and six – merge to form one
The fifth arch being completely absorbed
The 3rd and 4th arches fuse forming cervical sinus
If persists  cervical sinus (in lower neck, btw ICA & ECA to the
apex of the pyriform fossa
• Fourth and Six arches
 Cartilages: laryngeal cartilages
 Muscles: cricothyroid constrictors of the pharynx, intrinsic muscles of the
larynx
 Nerve: SLN, RLN (X)
 Fourth pouch: superior parathyroid gland
 Fifth pouch: ultimobranchial body
 Sixth pouch: intrinsic muscles of the larynx
5

6. 6

7. POUCH
Overall Structure
Specific Structures
1
tubotympanic recess
tympanic membrane, tympanic cavity,
mastoid antrum, auditory tube
2
intratonsillar cleft
crypts of palatine tonsil, lymphatic nodules
of palatine tonsil
3
inferior parathyroid gland, thymus
gland
4
superior parathyroid gland,
ultimobranchial body
5
becomes part of 4th pouch
7

8. 8

9. Triangles of the Neck
• SCM divides the neck into anterior and posterior triangles
• Triangles of the neck
 Anterior: submental, submandibular, carotid and muscular
 Posterior: lateral neck, subclavian
Anterior triangle
• Boundaries: SCM, inf. ramus of mandible, midline
• Submental:
 Boundaries: anterior belly of digastric, midline and hyoid bone
 Contains LN and submental salivary gland
9

10. • Submandibular:
 Boundaries: Inferior margin of mandible, anterior and posterior bellies of
digastric
 Deep boundary – stylohyoid and mylohyoid muscle
 Contains: SM salivary gland, deep fascia, LN, ant. facial vein, facial artery,
MM br. of VII n.
• Carotid:
 Boundaries: ant. border of SCM, post belly of digastric, superior belly of
omohyoid
 Contains: upper carotid sheath, LNs
10

11. • Muscular:
 Boundaries: lower anterior border of SCM, anterior belly of omohyoid, hyoid
bone, midline
 Contains: lower carotid sheath, infrahyoid strap muscles, upper
aerodigestive tract, thyroid and parathyroid gland
Posterior triangle
• Divided into lateral neck, subclavian triangles
• Lateral Neck:
 Boundaries: Posterior border of SCM, ant border of trapezius, sup. border of
inf belly of omohyoid
 Contains: cervical plexus, fibrofatty tissue, LN, XI nerve
11

12. • Sublavian:
 Boundaries: Lower border of Inf. belly of omohyoid, clavicle, post. border of
SCM
 Contains: fibrofatty tissue, scalene muscles, brachial plexus, subclavian
vessels, thyrocervical trunk, Sibson’s subpleural fascia and the pleura
 Trapezius muscle
• covers cervico-occiptal region
• represents the posterior neck
• rarely involved in detail
12

13. 13

14. 14

15. Fascial Layers
• Superfical
• Deep: investing layer, middle of visceral layer, deep layer
Superficial
• Invests platysma muscle
• Closely associated with adipose tissue
• Penetrated by the blood vessels that supply the neck skin
• Subplatysmal flap: protects the blood supply to the skin
15

16. Deep
1. Investing layer
• Arises from the ligamentum nuchae and the spinous process of
cervical vertebrae and invests the entire neck
• Splits to enlose the trapezius, omohyoid, SCM, strap muscles and the
parotid gland
• Superior attachment: external occipital protruberance, superior nuchal
line, mastoid tip an zygomatic arch
• The splitting of the facial layer around the parotid forms a deep layer
which fuses with the fascia around the ICA
• Forms stylomandibular ligament
• Anterior attachment: hyoid bone
• Inferior attachment: acromium, clavicle, sternum
16

17. 2. Carotid sheath
• Derived from the superficial layer of DCF medial to SCM
• Contains 80% of the LN of the neck, carotid arteries, IJV, X nerve
2. Middle layer, or pretracheal of visceral layer
• Derived from the superficial layer of DCF – passes deep to the strap
muscles and encircles the tracheal, thyroid and esophagus
• Movement of the hyoid and strap muscles during swallowing elevates
the fascia
2. Deep layer (prevertebral fascia)
• Arises from the ligamentum nuchae and the spinous process of the
cervical vertebrae
• Splits to enclose the postvertebral muscles, passes laterally around
the scalene muscles and then forms a layer over the vertebrae
• Forms the floor of the posterior triangles and allows the pharynx to
glide during deglutition
17

18. 18

19. Neck Spaces
Submental Space
• Midline spaces that lies between the anterior bellies of digastric
muscles
Submandibular Space
• Superf boundary: submandibular gland, digastric muscle
• Deep boundary: mylohyoid muscle
• Communicates with FOM around the posterior border of mylohyoid
Peritonsillar Space
• Between tonsil and superior constrictor
• Communicates through the fibres of the superior constrictor with
retropharyngeal and parapharyngeal space
19

20. 20

21. Parapharyngeal Space
• Inverted pyramidal shape
• Top: BOS; Inferior: Greater cornu of hyoid bone
• Medial: Sup constrictor; Lateral: Pterygoid muscles, mandible and
deep lobe of parotid gland
• Divided by styloid process into pre- and poststyloid spaces
• Prestyloid space contains ectopic salivary tissue
• Poststyloid space contains carotid arteries, internal jugular vein CN
IX-XII, cervical sympathetic chain and lymph node
21

22. 22

23. Retropharyngeal Space
• Sits between the two parapharyngeal spaces and is continuous
with both
• Superiorly: Skull base
• Anteriorly: musculature of pharynx
• Posteriorly: prevertebral fascia
• Contains only lymph node
• Continues inferiorly behind esophagus then with posterior
mediastinum
23

24. Pretracheal Space
• Lies anterior and lateral to the thyroid cartilage and deep to strap
muscles
• Contains Delphian node and communicates with the superior
mediastinum
Prevertebral Space
• Potential Space
• Lies btw cervical vertebrae and anterior longitudinal ligament
(posteriorly) and the prevertebral fascia (anteriorly)
• Extends down to 3rd thoracic vertebrae where the fascia is bound
to the vertebrae
• Infection in this space can rupture directly through into the
posterior mediastinum
24

25. Muscles
Sternocleidomastoid muscle
•
•
•
•
•
•
•
•
•
Has two heads of origin; that are from manubrium of sternum and clavicle
The manubrial tendon is attached to the front of the bone below the jugular
notch
The clavicular head arises from the superior surface of the medial third of the
clavicle
It is attached by a tendon to lateral surface of the mastoid process and by a thin
aponeurosis to the lateral half of the superior nuchal line
Spinal accessory nerve enters the muscle and runs through the deep part of it
and emerged at the posterior border of the muscle
It is enclosed within the investing layer of deep cervical fascia
It is crossed superficially by the greater auricular nerve, transverse cervical
nerve and external jugular vein
Deep to the upper half of the muscle lies the cervical plexus
Deep to its lower part lies the carotid sheath and its contents
25

26. •
•
•
•
•
•
The blood supply is derived from the branches of the occipital and superior
thyroid arteries
Is Innervated by the spinal part of accessory nerve mostly C2 and C3
Contraction of one muscle tilts the head towards ipsilateral shoulder, and
rotates the head and neck to opposite side
Both muscles acting together from below draw the head forwards
The muscles can assists in raising the roof of the thorax in forced inspiration
Can be tested by turning the face to the opposite side against resistance
and the muscle palpated
26

27. 27

28. Trapezius muscle
• Wide origin from the medial third of superior nuchal line,
ligamentum nuchae down to 7th cervical vertebrae and all the
spinous process and interspinal ligaments down to 12 th thoracic
vertebrae
• Superior fibres insert into clavicle and acromium
• Inferior fibres insert into the spine of the scapular
• Action: to rotate the scapular so that the glenoid fossa points up
• Paralysis is a common consequence damage to the accessory
nerve leading to malrotation of the scapular and traction on the
branchial plexus
28

29. 29

30. Omohyoid muscle
•
•
•
•
•
•
It arises from the upper border of the scapula, and occasionally from the
superior transverse scapular ligament which crosses the scapular notch
Inferior belly inclines forward and slightly upward across the lower part of
the neck, being bound down to the clavicle by a fibrous expansion
Inferior belly passes behind the sternocleidomastoid, becomes tendinous
and changes its direction
Superior belly lies close to the lateral border of the sternohyoid and inserted
into the lower border of the body of the hyoid bone
The central tendon of this muscle is held in position by a fascial sling
derived from investing layer of deep cervical fascia and is prolonged down
to be attached to the clavicle and first rib
The superior belly is supplied by the superior root of the ansa cervicalis with
the ansa supplies the inferior belly
30

31. •
•
The inferior belly of the omohyoid divides the posterior triangle of the neck into
an upper or occipital triangle and a lower or subclavian triangle
Its superior belly divides the anterior triangle into an upper or carotid triangle and
a lower or muscular triangle
31

32. 32

33. Digastric muscles
•
•
•
•
•
•
•
•
Posterior belly arises from the digastic notch on the medial surface of the
base of the mastoid process
Posterior belly tapers down to the intermediate tendon, which is attached to
the junction to the body and the greater horn of the hyoid bone
The tendon is lubricated by a synovial sheath within the fibrous sling
Anterior belly lies on the inferior surface of mylohyoid
Anterior belly connects the intermediate tendon to the digastrics fossa on
the inner surface of the mandible
Posterior belly is supplied by facial nerve
Anterior belly is supplied by the nerve to mylohyoid
The actions of the muscles are to depress and retract the chin and to assist
the lateral pterygoid in opening of mouth
33

34. 34

35. Strap muscles
• Comprises of sternohyoid, omohyoid, thyrohyoid and sternothyroid
muscles
• Move larynx and depress the mandible
• Supplied segmentally from C1, C2, C3 via the ansa cervicalis
• Retracted to access the trachea and thyroid gland
• Form the anterior boundaries of the neck level
35

36. 36

37. Cervical Lymphatics
• Divided into superficial and deep
• Superfical vessels perforate the cervical fascia and drain into the
deep
• Deep vessels:
 commonly found around blood vessels, nerves and muscles
 drain the mucosa of the mouth, OP, NP, larynx and hypopharynx
 group of nodes: submental, submandibular, jugular chain, posterior nodes
Submental
• Situated in the midline, inferior to mandible and between anterior
bellies of digastric muscles
• Drain the anterior floor of mouth
37

38. Submandibular
• Divided into six groups: preglandular, prevascular, retrovascular,
retroglandular, intraglandular and deep nodes
• Can be described as those related to submandibular gland those
related to facial vessels
• Cancers of FOM, tongue and buccal cavity metastasize more
commonly to the perivascular nodes - cleared in the neck
dissection
Jugular chain
• Closely associated with internal jugular vein
• Upper jugular nodes: drain the posterior faucial region esp
palatine tonsil
38

39. • Middle jugular nodes:
 Found between carotid bifurcation and the level at which omohyoid tendon
crosses IJV
 Drain larynx, midhypopharynx and upper thyroid gland
• Lower jugular nodes:
 Between tendon of omohyoid and down to the thoracic inlet
 Sometimes referred to as prescalene group of nodes
 Form an important confluence between the mediastinal node group, the
axillary group and the neck
 Neck nodes may appear secondary to disease outside the neck
39

40. 40

41. • Posterior nodes:
 Arranged into two groups:
• Along the accessory nerve: first echelon for nasopharynx
• Along the thyrocervical vessels: second echelon for the areas drained
by the anterior neck nodes
Lymph node levels
• Level I




Refers submental and submandibular nodes
Drains the lip, oral cavity and tongue
Subzone Ia: submental nodes; Drains ant FOM, lower lip, ventral tongue
Subzone Ib: submandibular nodes; Drains other subsite in oral cavity
41

42. • Level II






Forms upper jugular group of nodes
Drains the oropharynx, larynx, hypopharynx and parotid
IIa: Lies anterior inferior to Cr. XI
Iib: Lies posterosuperior
Positive Iia disease mandates Iib dissection
Elective dissection for laryngeal and hypopharyngeal malignancy can
exclude level Iib
• Level III
 Refers to middle jugular node
 Drains the larynx and pharynx
42

43. • Level IV
 Refers to lower jugular group of nodes
 Drains the larynx and hypopharynx
• Level V
 Refers to posterior triangle group of nodes
 Drains the other lymphatic regions in the neck
 Level Va:
• Superior to inf belly of omohyoid
• Contains the chain of nodes along the accessory nerve, which drain
the nasopharynx
 Level Vb:
• Inferior to inf belly of omohyoid
• Contains nodes related to the thyrocervical trunk which drains the
thyroid gland
43

44. • Level VI:
 Anterior or central group of nodes
 Paratracheal, perithyroidal, Delphian nodes
• Level VII:
 Corresponds to the superior mediastinal tissues
44

45. Level
II
Boundaries
Possible primary
Submental
Submandibular
Midline, body of hyoid, posterior belly digastric,
body of mandible
Lower lip, floor of mouth,
lower gum
Face, nose, PNS, oral cavity,
submandibular gland
Upper deep cervical
I
Nodes
Skull base above
Carotid bifurcation below (clinically – level of
hyoid)
Posterior belly digastric anteriorly
Sternomastoid posteriorly
Nasopharynx,
Oropharynx,
Hypopharynx,
Supraglottic larynx, Oral
cavity
Carotid bifurcation above
Superior belly of omohyoid (clinically level of
cricothyroid notch)
Sternomastoid posteriorly
Thyroid,
Larynx,
Hypopharynx, Cervical
esophagus
Superior belly of omohyoid above (clinically
cricothyroid notch)
Clavicle below
Sternomastoid posteriorly
? Carotid sheath anteriorly
Thyroid, esophagus, breast,
lung, GI
Sternomastoid anteriorly
Trapezius posteriorly
Clavicle below
Occipital – scalp, external ear
Supraclavicular
–
nasopharynx, thyroid,
esophagus, lung, breast
Midline anteriorly
Carotid sheath posteriorly?
Sup. Belly of omohyoid above?
Sternum below
Thyroid
upper 1/3 of IJV
adjacent spinal accessory
(= upper half of carotid triangle)
Middle deep cervical
III
- middle 1/3 of IJV
(=lower half of carotid triangle)
Lower deep cervical
IV
lower 1/3 of IJV
(= part of muscular triangle behind carotid sheath)
Posterior triangle
V
-
spinal accessory group
supraclavicular group
Anterior neck between carotid sheaths
VI
prelaryngeal
pretracheal
paratracheal
(=part of muscular triangle in front of carotid
sheath)
45

46. 46

47. Major Blood Vessels
Common carotid artery
•
•
•
•
•
•
The common carotid artery on the left side arises from the arch of aorta, where it
lies in front of the subclavian artery up to the sternoclavicular joint
The common carotid artery on the right side arises from brachiocephalic trunk
where it bifurcates behind the sterno-clavicular joint
The common carotid artery gives off no branches proximal to its bifurcation
It lies within the medial part of carotid sheath, where the internal jugular vein lies
lateral to it and the vagus nerve deeply placed between the two vessels
The sympathetic trunk is behind the artery and outside the sheath, which is
overlapped superficially by the infrahyoid mucles and sternocleidomastoid
It usually bifurcates into the external and internal carotids at the level of the
upper border of the lamina of the thyroid cartilage (upper border of C4
vertebrae)
47

48. •
•
The terminal portion of the artery is often dilated into the carotid sinus, which
includes the comancement of the internal carotid artery
The surface marking of the common carotid artery is along a vertical line from
the sternoclavicular joint to the level of the upper border of the thyroid gland
48

49. 49

50. External carotid artery
•
•
•
•
•
•
•
It lies against the side wall of the pharynx somewhat medial to the internal
carotid artery
It then ascends in front of the internal carotid deep to the posterior belly of
digastric and stylohyoid
It pierces the deep lamina of the parotid fascia and enters the gland
It divides within the gland behind the neck of the mandible into the maxillary
and superficial temporal arteries
It is separated from the internal carotid by deep part of the gland and its fascia,
styloid process and its continuation the styloid ligament, styloglossus and the
‘pharyngeal structures’
The facial vein crosses the artery, with the hypoglossal nerve lying between
The surface marking is along a line of bifurcation of the common carotid
passing up behind the angle of mandible to a midpoint immediately in front of
tragus of the ear
50

51. 51

52. Internal carotid artery
•
•
•
•
•
•
It arises at the bifurcation of the common carotid and continues upwards within
the carotid sheath
At its commencement is the carotid sinus where its contained baroreceptors
are supplied by the glossopharyngeal and vagus nerves
The carotid sinus contains baroreceptors which mediate blood pressure
impulses to medullary centres
The carotid body is a small structure from which it receives two or three small
glomic arteries
The carotid body’s cells are chemoreceptors concerned with respiratory
reflexes and are innervated by the glossopharyngeal and vagus nerves
It lies lateral to lateral to the external carotid at its origin, but soon passes up
posteriorly to a medial and deeper level
52

53. •
•
It has no branches in the neck
It passes straight up in the carotid sheath, beside the pharynx, to the carotid
canal in the base of the skull
Internal jugular vein
•
•
•
•
It emerges from the jugular bulb at the posterior compartment of the jugular
foramen
At first behind the internal carotid artery, it lies on the transverse process of the
atlas, crossed by the accessory nerve
It receives the inferior petrosal sinus as its first tributary just below the base of
skull
The vein passes down to gain lateral side of the internal carotid artery
53

54. •
•
•
•
•
•
•
•
The deep cervical lymph nodes are closely adjacent to the vein throughout its
course
Its posterior relations include the cervical plexus and the phrenic nerve
The thoracic duct crosses behind the left vein at the level of C7 vertebrae
The inferior root of the ansa cervicalis curls around its lateral border, to unite
with the superior root at the variable level in front of the vein
The terminal part of the vein lies deep to the triangular interval between the
sterna and clavicular heads of sternocleidomastoid
It joins the subclavian veinto form the brachiocephalic vein behind the sternal
end of clavicle
Its tributaries below the inferior petrosal sinus are pharyngeal, lingual, facial
and superior and middle thyroid veins
At its commencement and termination of the vein slightly dilated to from
superior and inferior bulb
54

55. External jugular vein
•
•
•
Forms a variable superficial system of vein along with posterior EJV and AJV
Drains blood from the face and scalp
Enters the subclavian vein where there are valves at the entrance with a further
set of veins at 4 cm proximal
55

56. Nerves
Marginal Mandibular br. of Cr. VII
•
•
•
•
•
•
Runs inferior to the angle of mandible
Dips down into the neck and runs superficial to the submandibular triangle
Runs just deep to platysma and superficial to the deep fascia
Runs inferior to the greater cornu of the hyoid bone
Curves upwards and crosses mandible for a second time to the facial artery and
vein
Supplies depressor anguli oris, risorius, muscles of the lower lip
56

57. 57

58. Glossopharyngeal nerve
• Trematic nerve of the third pharyngeal arch
• Exits the skull at the anterior compartment of the jugular foramen
• Has an inferior ganglion in the neck – contains cell bodies of the
sensory fibres
• Passes down on the ICA then curves anteriorly around
stylopharyngeus, deep to hyoglossus and reaches the tongue
• Branches:
 Tympanic branch (Jacobson’s nerve)
• Supplies sensation to the middle ear
• Parasympathetic supply to the parotid gland via tympanic plexus
58

59.  Motor branch to stylopharyngeus
 Carotid sinus nerve: main supply to the carotid sinus and carotid body
 Pharyngeal branches: join the pharyngeal plexus on the middle constrictor
muscle
 Tonsillar branch: supplies the mucous membrane over the palatine tonsil
 Lingual branch:
• Supplies the posterior one-third of the tongue with sensory fibres and
secretomotor fibres to the glands of the posterior third
59

60. 60

61. 61

62. Vagus nerve
• Trematic nerve for 4th branchial arch
• Exits the skull base through the middle compartment of jugular
foramen
• The nerve dilates to form the inferior ganglion beneath the skull
base
• Below the ganglion, the vagus receives a branch from the
accessory nerve
• Runs in the carotid sheath between the IJV and the ICA and CCA
• Branches:
 Auricular branch (arnold’s nerve): supply the TM and ear canal skin
 Carotid body branches: supplements the glossopharyngeal branch
 Pharyngeal branches: supply motor innervation to the constrictors and
62
soft palate

63.  Superior laryngeal branches:
• Leaves the vagus high in the neck
• Divides at the level of the hyoid into external and internal laryngeal
nerves
 Cardiac branches: Leave the vagus low in the neck and form the cardiac
plexus
 Recurrent laryngeal branches:
• Branches low in the neck
• Left hooks around ligamentum arteriosum and arch of aorta and then
runs cranially in the tracheo-esophageal groove
• Right runs along the subclavian artery before coursing medially towards
the tracheo-esophageal groove
63

64. 64

65. Spinal accessory nerve
•
•
•
•
•
•
•
•
Formed in the posterior cranial fossa by the union of spinal and cranial part
Emerges from the skull base through the middle compartment of the jugular
foramen, lateral to the vagus nerve
Cranial component joins the vagus just inferior to the inferior ganglion
Runs in contact with IJV, inf to the lateral mass of atlas and passes into the SCM
Supplies motor input only to SCM from C2 and C3 roots
Exits the SCM at the junction of the upper and middle thirds of the posterior
border
Runs across the posterior triangle btw the deep and superf layers of DCF
Enters trapezius at the junction of its lower and middle thirds
65

66. 66

67. Hypoglossal
•
•
•
•
•
•
Exits the skull through hypoglossal canal
Courses around the inferior vagal ganglion
Runs inferior around ICA then ECA to pass below the posterior belly of the
digastric
Runs around the stylomastoid branch of the occipital artery, ECA, lingual artery
and inferior to the greater horn of hyoid bone
It then courses upwards deep to hyoglossus and divides to supply all intrinsic
muscles of tongue and extrinsic muscle, except the palatoglossus
Gives the upper root of the ansa cervicalis
67

68. 68

69. Cervical plexus
•
•
•
•
•
•
•
Is formed by loops between the anterior rami of the upper four cervical nerves
Lies in the series with brachial plexus on the scalenus medius behind the
prevertebral fascia
It is covered by the upper part of sternocleidomastoid
Does not lie in the posterior triangle
The upper three cervical nerves have meningeal branches for the posterior
cranial fossa
The C1 fibres ascend with the hypoglossal nerve
The C2 and C3 fibres ascend thru the foramen magnum
69

70. • Muscular branches of cervical plexus
 Are given off segmentally to prevertebral vessels (longus capitis, longus
colli and scalenes)
 The fibres from the branch of C1 are carried to superior root of ansa
cervicalis and nerves to thyrohyoid and geniohyoid
 Branches from C2 and C3 are to the sternocleidomastoid, while branches
from C3 and C4 are to the trapezius
 The inferior root of ansa cervicalis is formed by union of a branch each from
C2 and C3
 The inferior root of ansa cervicalis descends to join the superior root (C1) at
the ansa
70

71. • Cutaneous branches of cervical plexus
 Generally supply the front and sides of the neck and contribute to the supply
of the scalp, face and chest
 Lesser occipital nerve (C2) supplies posterior aspect of the upper neck
adjacent scalp behind the auricle as well as the auricle
 Transverse cervical nerve divides into ascending and descending branches
and innervate the skin of the front of neck from chin to the sternum
 Supraclavicular nerve emerges with the other three nerves at the posterior
border of sternocleidomastoid and soon divides into several branches
 Greater auricular nerve is a large trunk passing upwards over
sternocleidomastoid
71

72. 72

73. 73

74. 74