Neck anatomy

1. SURGICAL ANATOMY OF
NECK
Dr Sruthi S Suresh
DNB resident
Dept of ENT

2. • upper border of the neck –
Anteriorly- floor of mouth
Posteriorly- skull base
• lower border is the upper border of the first
rib and body of the first thoracic vertebra

3. Root of the neck
•The manubrium, sternoclavicular joints and
the clavicles form the surface landmarks of
root of the neck.
• The superior surface of the manubrium is
jugular notch and above this is the
suprasternal fossa or Burn's space.
• Laterally, the clavicles articulate with the
acromium forming the anterior boundary of
the root of the neck

5. Mandible
represents the upper border of
neck.
 The superficial lobe of the
submandibular gland can be
palpated just inferior to the lower
border of the inferior ramus of the
mandible.

6. Hyoid
 The body and greater cornu of the hyoid
bone are important bony landmarks in the
neck.
 The body is in the midline and the greater
cornu is just inferior to the angle of the
mandible.
 The greater cornu acts as a guide to the
lower extent of the course of the marginal
mandibular branch of the facial nerve and it
divides node levels II and level III

7. Thyroid cartilage
•Just inferior to the
body of the hyoid is
the thyroid
• The thyrohyoid
membrane links the
two.
pierced by superior
laryngeal vessels
internal laryngeal
nerve.

8. Cricoid cartilage
Lies at C6 level
 can be palpated inferior to the thyroid
cartilage in the midline.
 Between the two is the cricothyroid
membrane. the site of emergency
surgical airway.

10. Trachea
The cervical trachea can be palpated just
inferior to the cricoid cartilage.
Thyroid gland
•The isthmus can be palpated overlying the
trachea between the second and fourth
• The thyroid lobes lie deep to the
sternocleidomastoid muscles and cannot be
palpated unless enlarged.

11. SUPERFICIAL MUSCLES OF NECK

12. PLATYSMA- action-
muscle of facial expression
1. draws corners of mouth inferiorly and widens it.
2. draws skin of neck superiorly when teeth are
clenched.
Importance- subplatysmal flap is raised during neck
surgeries to protect blood supply to skin.
STERNOCLEIDOMASTOID- action-
flexes and rotates the head
importance- divides neck into anterior and posterior
triangles.
On its deep surface is carotid sheath.
TRAPEZIUS- action-
stabilises scapula.

14. Superficial fascia:
Invests platysma muscle
Closely associated with adipose
tissue
Penetrated by the blood vessels
that supply the neck skin
Marginal mandibular br of facial n.
lies just deep to superficial
cervical fascia.

15. Deep cervical fascia:(fascia colli)
Form the boundaries of
compartments
Allow the neck structures to glide
past one another
Supports the thyroid gland, lymph
nodes, blood vessels
Used as a guide for surgical
dissection of neck

16. Deep cervical fascia is condensed
to form following layers-
1. Investing layer
2. Pretracheal fascia
3. Prevertebral fascia
4. Carotid sheath
5. Buccopharyngeal fascia
6. Pharyngobasilar fascia

19.  Investing layer
• Arise from the ligamentum nuchae and the spinous
processof cervical vertebrae and invests the entire
neck
• Splits to enclose
• Muscles- Trapezius and Sternocleidomastoid
• Salivary glands- Parotid and Submandibular
• Spaces- Suprasternal and Supraclavicular
• Superior attachment: external occipital protuberance,
superior nuchal line, mastoid tip and zygomatic arch
• The splitting of fascial layer around the parotid forms
a deep layer which fuses with the fascia around the
ICA
• Forms stylomandibular ligament.
• Inferior attachment : spine of scapula , acromian
process, clavicle and manubrium.

20. Pretracheal fascia:
The importance of this fascia is that
it encloses and suspends the
thyroid gland and forms its false
capsule.
• Movement of the hyoid and strap
muscles during swallowing
elevates the fascia

21. Prevertebral fascia:
• Arises from the ligamentum nuchae
and the spinous process of the
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 degluttition.

22.  Carotid sheath: Formation- formed on
anterior aspect by pre-tracheal fascia and on
posterior aspect by prevertebral fascia.
Contents- common or internal carotid arteries
arteries , internal jugular vein and vagus
nerve.
Relations-
• The ansa cervicalis lies embedded in the
anterior wall of carotid sheath.
• The cervical sympathetic chain lies behind
the sheath, plastered to the prevertebral
fascia.
• The sheath is overlapped by the anterior
border of the sternocleidomastoid .

23. Danger space of neck:
Space between alar fascia and prevertebral
fascia; since infection from here can spread
thorax.
Injury to EJV: Division of the external
jugular vein in the supraclavicular space
cause air embolism and consequent death
because the cut ends of the vein are
prevented from retraction and closure by
fascia , attached firmly to the vein.

25. Anterior triangle of neck
Medially- midline of neck
Laterally- anterior border of SCM muscle
Superiorly- base of mandible
• subdivided into smaller triangles by the
digastric muscle and the superior belly of
the omohyoid into
Submental
Digastric
Carotid
Muscular triangle

27. Submental triangle
• Bounded by anterior
belly of the
corresponding
digastric muscles on
each side
• base- body of
bone
• Apex- lies at chin
• Floor- right and left
mylohyoid muscles
and the median
raphe uniting them

29. Contents:
• Two to four small submental
lymph nodes
• Small submental veins join to
the anterior jugular veins

30. Digastric triangle:
Anteroinferiorly- anterior belly of digastric
Posteroinferiorly – posterior belly of
and stylohyoid
Superiorly – base of mandible and line
angle of mandible to mastoid process

31. Roof : -skin
-superficial fascia containing
platysma ,the cervical branch of facial n.
and ascending branch of transverse or
anterior cutaneous nerve of neck.
-deep fascia, which splits to
enclose the submandibular salivary
gland
Floor : mylohyoid muscle anteriorly and
the hyoglossus posteriorly.

33. Contents:
In the anterior part of
triangle
• Superficial part of the
submandibular
gland
• Facial vein and the
submandibular lymph
nodes are superficial
it and the facial artery
is deep to it
• Submental artery
• Mylohyoid nerve and
vessels
• Hypoglossal nerve

34. In the posterior part of the
triangle
• Superficial structures:
-lower part of the parotid
gland
-external carotid artery before
it enters parotid gland

35. • Deepest structures:
-internal carotid artery
-internal jugular vein
-vagus nerve

36. Carotid triangle
•Anterosuperiorly- posterior belly of
and stylohyoid
•Anteroinferiorly- superior belly of omohyoid
•Posteriorly- anterior border of SCM

37. • Roof : skin, superficial fascia( platysma,
cervical branch of the facial nerve,
transverse cutaneous nerve of the neck)
and investing layer of the deep cervical
fascia
• Floor : formed from the middle
constrictor muscle,inferior constrictor of
the pharynx and thyrohyoid membrane

40. Contents:
ARTERIES
1. Common carotid artery with carotid sinus and
carotid body.
2. Internal carotid artery.
3. External carotid artery with its superior
thyroid,lingual,facial,ascending pharyngeal and
occipital branches.
VEINS
1.Internal jugular vein
2. Common facial vein
3.Pharyngeal vein
4.Lingual vein

41. NERVES
1.Vagus nerve
2. Superior laryngeal branch of vagus
dividing into external and internal
laryngeal nerves.
3. The spinal accessory nerve running
backwards over the internal jugular vein.
3.Hypoglossal nerve[running forwards
over the external and internal carotid
arteries] and its branches upper root of
the ansa cervicalis (descedens hypoglossi)
and branch to the thyrohyoid
4.Sympathetic chain
LYMPH NODES
1.Deep cervical lymphnodes along IJV
include
.Jugulodigastric node below posterior
belly of digastric
.Jugulo omohyoid node above the
inferior belly of the omohyoid.

42. MUSCULAR
•Anteriorly- anterior median line of
from hyoid bone to sternum
•Posterosuperiorly-superior belly of
omohyoid
•Posteroinferiorly-lower part of
border of SCM ms
CONTENTS-
•Infrahyoid ms/strap ms/ribbon ms
These are:
1) Sternohyoid
2) Sternothyroid
3) Thyrohyoid
4) Omohyoid
Arranged in two layers
Superficial: sternohyoid and
Deep: sternothyroid and thyrohyoid

44. Posterior triangle
The posterior triangle can be divided by the
inferior belly of omohyoid, into occipital part and
supraclavicular part.

45. Ant- post border of SCM
Post- ant border of trapezius
Inf- middle third of clavicle
Apex- on the superior nuchal line where
trapezius and SCM meet.
Roof- skin, platysma, superficial layer of DCF
Floor- splenius capitus, levator scapulae and
posterior, middle and anterior scalene
muscles covered by prevertebral fascia.

46. LATERAL NECK
TRIANGLE/OCCIPITAL
TRIANGLE
BOUNDARIES-
Posterior border of SCM
Anterior border of trapezius
Superior border of inferior belly of
omohyoid
•Spinal accessory nerve
•Lesser occipital, greater auricular, ant,
cutaneous nerve of neck, supraclavicular
nerves
•Muscular branches to levator
scapulae,trapezius, rhomboideus, upper

47. SUBCLAVIAN
TRIANGLE/SUPRACLAVICU
LAR TRIANGLE/omo
clavicular or Ho’s triangle
BOUNDARIES-
Lower border of inferior belly of
omohyoid
Clavicle
Posterior border of SCM
• The contents are
tissue, the scalene
the brachial plexus and the
subclavian vesseIs,
the thyrocervical trunk.
• Also included are Sibson's
suprapleural fascia and the
pleura. The trapezius
the cervico-occipital region
and represents the
neck.

48. contents
nerves- Brachial plexus
N to SA
N to subclavius
Suprascapular nerve.
Vessels- 3rd part of subclavian Artery & subclavian vein
Suprascapular Artery and vein
Transverse cervical A
Lower part of EJV
lymphnodes

50. CERVICAL LYMPHATICS
•The cervical lymphatics are divided into
superficial and deep.
• The superficial perforate the cervical
fascia and drain into the deep
•The deep lymphatic vessels and nodes
most densely associated with fascial
condensations.

53. Submental group / IA
•These nodes are situated in the
inferior to the mandible and between
the anterior bellies of the digastric
muscles.
• They drain the anterior floor of the
mouth and tip of tongue.
•Submandibular triangle/ IB
•Within the submandibular triangle-
cavity, nasal cavity ant, soft tissue
structures of midface, SM gland

54. LEVEL II
Uppermost nodes of jugular chain extending
from skull base to the level of inferior
of hyoid bone/carotid bifurcation.
The spinal accessory nerve subdivides level
into IIA(medial to SAN)and IIB.( lateral to
Drain –Oral cavity,Nasal Nasopharynx
Oropharynx,Larynx,Hypopharynx,Parotid
LEVEL III
Sup- inferior border of hyoid
Inf- inf border of cricoid
Drain- NP, OC, OP, HP, larynx

55. LEVEL IV
Extends from the level of inferior border of
cricoid to the clavicle.
The omohyoid muscle crosses the superior
aspect of this level.
Drain the hypopharynx and larynx,thyroid,
cervical esophagus

56. Posterior nodes /V
•Arranged into two groups:
•VA- SAN
•VB- transverse cervical vessels &
supraclavicular nodes.
•Drain nasopharynx, oropharynx,posterior
neck and scalp.

57. Anterior compartment- level VI
 Pretracheal & paratracheal, precricoid( delphian), perithyroidal
nodes
 Sup- hyoid
 Inf- suprasternal notch
 Lat- CCA on each side
 Drain- thyroid,glottic,subglottic, apex of PFS, cervical esophagus
 Level VII- superior mediastinum
 Extend inferiorly below the suprasternal notch along each side of
cervical trachea to level of innominate artery

60. Common carotid artery
•Arises from the brachiocephalic artery on the right
and the arch of the aorta on the left.
•Surface markings are the sternoclavicular joint,
tubercle of lateral process of C6 (Chassaignac's
tubercle) and it
•Bifurcates at the level of the greater cornu of the
hyoid.

62. The internal carotid
artery
Terminal branch of common carotid artery
• has no branches in the neck and
lies deep and lateral to the external
branch after the bifurcation. It runs
beneath the posterior belly of
to enter the skull via the carotid
•Anterolaterally- IJV

63. Anterior/superficial-
In carotid triangle
Anterior border of SCM
External carotid artery is anteromedial to it
Above carotid triangle
Posterior belly of digastric
Stylohyoid
Stylopharyngeus lateral-
Styloid process internal jugular
vein
Parotid gland with structures within it
temporomandibular joint
Posteriorly-
Superior cervical ganglion
Carotid sheath
Glossopharyngeal ,vagus,accessory and hypoglossal nerves at base of skull
Medial-
Pharynx

64. The external carotid artery
Terminal branch of common carotid artery
• It courses in a straight line from the
greater cornu of the hyoid to a point
between the mastoid and ascending
of the mandible.
• It terminates in the substance of the
parotid gland, the terminal branches are
the superficial temporal and maxillary
artery.
• Before entering the deep surface of the
parotid gland, the artery gives off six

67. LINGUAL ARTERY

68. The lingual artery arises from from the external carotid artery opposite
the tip of the greater cornu of hyoid bone.
It is divided into three parts by the hyoglossus muscle.
First part lies in carotid triangle. Forms a characteristic upward loop
which is crossed by hypoglossal nerve.
Second part lies deep to hyoglossus along the upper border of hyoid
bone.
Third part runs upwards along the anterior border of hyoglossus and
then horizontally forwards on the undersurface of tongue as the fourth
part.
During surgical removal of tongue ,the first part of the artery is ligated
before it gives any branch to the tongue or tonsil.

70. Internal jugular vein
•The surface anatomy of the internal jugular vein in
the neck is the lobule of ear to the medial end of the
clavicle, running deep to the sternal and clavicular
heads of the sternocleidomastoid.
•The internal jugular vein is a continuation of the
sigmoid sinus and is a thin-walled capitance vessel. It
exits the skull in the posterior compartment of the
jugular foramen.
• the sternocleidomastoid muscle lies
superficial to both the IJV and the carotid
arteries, providing protection from the
penetrating trauma.
•The posterior belly of digastric and inferior
belly of omohyoid ms both cross over the IJV.

71. •At its origin exists the superior bulb, which is deep to
the posterior floor of the tympanic cavity. The vein
runs in the carotid sheath and joins the subclavian
vein to form the brachiocephalic vein at the sternal
end of the clavicle.
At its termination the internal jugular vein has an
inferior bulb, which is the only part of the vessel that
contains valves.

73. External jugular vein
•It enters the subclavian vein where there are
valves at the entrance with a further set of
veins at 4 cm proximaL These are inefficient
and do not prevent reflux of blood.
•The external jugular vein has a node, the
external jugular node, which drains the
parotid gland and is important in malignancy.

75. Marginal mandibular branch of the facial nerve
•This nerve runs inferior to the angle of the mandible,
dips down into the neck and runs superficial to the
submandibular triangle.
• The nerve runs just deep to the platysma and is
superficial to the deep fascia. It runs inferior to the
cornu of the hyoid bone.
• It curves upwards and crosses the mandible for a
time close to the facial artery and vein.
• It lies deep to the depressor anguli oris, which it
It also supplies risorius and the muscles of the lower
•Its action is to move corner of mouth and lower lip.
•This nerve is most at risk during submandibular gland
excision and clearance of lymph node level I . Nerve
be protected by incising the investing layer of deep
cervical fascia inferior to the lower border of
submandibular gland or just above the hyoid bone and
reflecting the fascia superiorly along with the facial
retracting the nerve out of the surgical field.

77. Glossopharyngeal
•It exits the skull at the anterior
compartment of the jugular foramen.
•It passes down on the internal carotid artery
then curves anteriorly around the
stylopharyngeus, deep to the hyoglossus
and reaches the tongue.
• Its branches are the tympanic or Jacobson's
nerve, which supplies sensation to the
middle ear and parasympathetic supply to
the parotid gland from the inferior salivary
nucleus via the tympanic plexus.
•It has a motor branch that supplies the
stylopharyngeus.

78. •. The carotid sinus is innervated by a
branch of the glossopharyngeal nerve. It
takes baroreceptor and chemoreceptor
information to the brainstem.
• Pharyngeal branches join the
pharyngeal plexus, which is probably
sensory on the posterolateral surface of
the middle constrictor.
•The tonsillar branches supply sensation
to the tonsil mucous membrane.
• Lingual branches supply the posterior
third of tongue with taste, sensation and
secretomotor fibres

80. Vagus
nerve of the fourth branchial arch.
exits the skull base through the middle
compartment of the jugular foramen.
The vagus runs in the carotid sheath between
internal jugular vein and the internal and
carotid artery. Its branches are the:
• auricular branch;
• carotid body branches;
• pharyngeal branches;
• superior laryngeal branches;
• cardiac branches;
• recurrent laryngeal branches.

81. •The auricular branch, or Arnold's nerve, runs
between the mastoid and the tympanic plate
to supply tympanic membrane and ear canal
skin and contributes to referred pain from the
neck to the ear.
•The pharyngeal branch slopes across the
internal carotid· and joins the pharyngeal
plexus on the middle constrictor.
•Superior laryngeal nerve leaves the vagus
high in the neck, runs deep to the internal
carotid and divides at the level of the hyoid
into external and internal laryngeal nerves.

82. The recurrent laryngeal nerve
•It branches low in the neck.
•The left hooks around the ligamentum
arteriosum and arch of aorta and then runs
cranially in the tracheooesophageal groove.
•The right is more variable than the left and
usually runs around the subclavian artery
before coursing medially towards the
oesophageal groove

83. •. It may run deep, through or
superficial to the inferior thyroid artery
and its branches before it perforates
the cricothyroid membrane.
•BEAHR’S TRIANGLE which is formed by
the CCA laterally, the inferior thyroid
vessels and recurrent laryngeal nerve.

85. Spinal accessory
•The spinal accessory runs in contact
with the internal jugular vein, inferior
the lateral mass of the atlas and
into the sternocleidomastoid.
•The commonest cause of iatrogenic
accessory nerve damage is during
V neck dissection which may be
permanent or transient.

86. • motor input only to the sternocleidomastoid
muscle from the C2 and C3 roots
•. The accessory nerve exits the muscle at the
junction of the upper and middle thirds of the
posterior border, a point known as Erb's point.
• It runs across the posterior triangle between
the deep and superficial layers of the deep
cervical fascia.
The nerve enters the trapezius at the junction
of its lower and middle thirds.The trapezius
muscle is supplied from C3 and C4 roots.

88. Hypoglossal
•The nerve courses around the inferior vagal
ganglion then runs inferior around the internal
carotid and then the external carotid artery to
pass below the posterior belly of the digastric.
• It then runs around the stylomastoid branch
of the occipital artery, the external carotid and
the lingual artery and inferior to the greater
horn of the hyoid bone
•. It then courses upwards deep to hyoglossus
and divides to supply all the intrinsic muscles
of the tongue and all the external muscles,
except the palatoglossus

89. • It is entirely a motor
•Most vulnerable at the greater cornu of
the hyoid.
•It passes between the internal jugular vein
and the internal carotid artery and runs on
the internal jugular vein.
•The fibres are derived from the C1 nerve
root and supply the strap muscles.

90. ANSA CERVICALIS/ANSA HYPOGLOSSI
 Thin nerve loop which lies embedded in anterior wall of carotid sheath.
infrahyoid ms.

 DISTRIBUTION
 superior root- to superior belly of omohyoid
 ansa cervicalis- to sternothyroid and sternoh
 inferior root- to inferior belly of omohyoid

91. SUPRAHYOID MUSCLES

93. INFRAHYOID MUSCLES