The posterior triangle of the neck is bounded anteriorly by the sternocleidomastoid muscle, posteriorly by the anterior border of the trapezius muscle, and inferiorly by the middle third of the clavicle. It contains the spinal part of the accessory nerve, branches of the cervical plexus, the external jugular vein, and the brachial plexus. The triangle is divided into an occipital triangle superiorly and a supraclavicular triangle inferiorly by the inferior belly of the omohyoid muscle.

1. Posterior triangle ofPosterior triangle of
neckneck
Dr Pratik Mistry

2. 22
STERNOCLEIDOMASTOID
Sternocleidomastoid
is a strap muscle.
It extends obliquely
across the side of
the neck.
It forms a prominent
surface landmark.
It divides the side of
the neck into
anterior & posterior
triangles

3. 33
The neck is divided into
anterior and
posterior triangles by
sternocleidomastoid
Anterior triangle lies
in front of the muscle
Posterior triangle lies
behind it.
TRIANGLES OF THE NECK

4. Torticollis (wry neck)Torticollis (wry neck)

5. 55
Boundaries of the
Posterior triangle:
Anteriorly: posterior
border of sternomastoid
Posteriorly: anterior
border of trapezius
Inferiorly: middle third
of the clavicle.

6. 66
OMOHYOID MUSCLE
The omohyoid
muscle has:
 Inferior belly
 Intermediate
tendon
 Superior
belly.

7. 77
The inferior belly
of omohyoid
subdivides the
posterior triangle
into:
 a large occipital
triangle above
a small
supraclavicular
triangle below.

8. 88
The roof of the triangle is
covered by:
 Skin.
 superficial fascia, which
contains:
 platysma,
 cutaneous branches of
cervical plexus
 External jugular vein
 Investing layer of deep
cervical fascia.

10. 1010
PLATYSMA MUSCLE
The platysma can
be seen as a sheet
of muscle by
asking the patient
to clench the jaws
firmly.
It extends from
the body of the
mandible
downward over
the clavicle onto
the anterior
thoracic wall.

11. 1111
Running across
the triangle in its
covering:
the cutaneous
branches of
cervical plexus

13. 1313
BRANCHES OF THE CERVICAL PLEXUS
The cervical plexus is
formed by the anterior
rami of C1,C2,C3 &
C4.
Several cutaneous
nerves emerge from
under the middle of
the posterior border
of the sternomastoid
muscle.
They innervate parts
of the skin in the head
and neck region.

14. 1414
LESSER OCCIPITAL NERVE
The lesser occipital
nerve is a branch of
C2.
It hooks around the
accessory nerve and
ascends along the
posterior border of the
sternomastoid muscle
It supply the skin over
the lateral part of the
occipital region and
the medial surface of
the auricle.

15. 1515
GREAT AURICULAR NERVE
The great auricular
nerve is a branch of
C2 & C3.
It ascends across
the sternomastoid
where it divides into
branches that
supply the skin over
the angle of the
mandible, the
parotid gland, and
the auricle.

16. 1616
TRANSVERSE CERVICAL NERVE
Transverse cervical nerve
of the neck is a branch of
C2 and C3.
It emerges from behind
the middle of the
posterior border of the
sternomastoid.
It passes forward across
that muscle and divides
into branches that supply
the skin on the anterior
and lateral surfaces of the
neck, from the body of
the mandible to the
sternum.

17. 1717
SUPRACLAVICULAR NERVES
The supraclavicular
nerves are branches
of C3 and C4.
They emerge from
beneath the posterior
border of the
sternocleidomastoid
muscle and descend
across the side of the
neck.
They pass onto the
chest wall and
shoulder region, down
to the level of the
second rib.

18. 1818
EXTERNAL JUGULAR VEIN
The External
jugular vein
begins just
behind the angle
of the mandible
by the union of
the posterior
auricular vein
with the
posterior division
of the
retromandibular
vein.

20. 2020
TRIBUTARIES Posterior auricular
vein.
Posterior division of
the retromandibular
vein.
Transverse cervical
vein.
Suprascapular vein.
Anterior jugular vein.
Posterior external
jugular vein, a small
vein that drains the
posterior part of the
scalp and neck and
joins the external
jugular vein about
halfway along its
course.

21. Notice:
The cutaneous
branches of
cervical plexus
& the external
jugular vein are
contents and in
the same time
they run in the
roof of the
triangle

22. Parts of Deep
cervical
fascia:
Investing
layer.
Prevertebral
layer.
Pretracheal
layer.
Carotid
sheath.

23. 2323
The FLOOR of the
triangle is covered by the
prevertebral layer of
deep cervical fascia.
It is formed from below
upward by the:
– Scalenus medius.
– Scalenus posterior
– Levator scapulae
– Splenius capitis, &
Semispinalis capitis,
A small part of the
scalenus anterior may
be present, but it is
usually overlapped and
hidden by the
sternocleidomastoid.

24. Contents of occipital triangleContents of occipital triangle
Spinal part ofSpinal part of
accessory nerveaccessory nerve
C3 & C4 nervesC3 & C4 nerves
Nerve toNerve to
rhomboidusrhomboidus
Four cutaneousFour cutaneous
branches ofbranches of
cervical plexuscervical plexus
Upper trunk ofUpper trunk of
brachial plexusbrachial plexus
Occipital arteryOccipital artery

25. 2525
ACCESSORY NERVE
(SPINAL PART)
The spinal part of
the accessory nerve
enters the posterior
triangle by emerging
from beneath the
middle of the
posterior border of
sternomastoid.
It runs downward
and laterally across
the posterior triangle
on the levator
scapulae muscle

26. 2626
OCCIPITAL ARTERY It is a branch of the
external carotid
artery.
It enters the posterior
triangle at its superior
angle, appearing
between the
sternomastoid &
trapezius muscles.
Then, it ascends in a
tortuous course over
the back of the scalp,
accompanied by the
greater occipital
nerve.

27. Contents of supraclavicular triangleContents of supraclavicular triangle
Third part ofThird part of
subclavian arterysubclavian artery
Subclavian veinSubclavian vein
External jugularExternal jugular
veinvein
Trunks of brachialTrunks of brachial
plexusplexus
Superficial cervicalSuperficial cervical
arteryartery
Suprascapular a.Suprascapular a.
Dorsal scapular a.Dorsal scapular a.
Supraclavicular LNSupraclavicular LN

28. 2828
THIRD PART OF THE SUBCLAVIAN ARTERY
The subclavian artery
is divided into three
parts by the scalenus
anterior muscle, which
crosses in front of the
artery.
 First part medial to
scalenus anterior.
 Second part lies
behind the muscle.
 Third part extends
from the lateral border
of the muscle to the
outer border of the first
rib; where, it is
continuous as the
axillary artery.

29. 2929
The third part of the subclavian artery enters the
anteroinferior angle of the posterior triangle and
disappears behind the middle of the clavicle.

30. 3030
BRACHIAL PLEXUS
The brachial
plexus is formed
from the
anterior rami of
the C 5th
, 6th
, 7th
,&
8th
&T 1st
.
It lies in the
subclavian
triangle of the
posterior
triangle.

31. 3131
The trunks of the
brachial plexus
enter the posterior
triangle of the
neck through the
interval between
the scalenus
anterior and the
scalenus medius
muscles.

32. Branches of supraclavicular part ofBranches of supraclavicular part of
brachial plexus in the trianglebrachial plexus in the triangle
Nerve toNerve to
rhomboidsrhomboids
Nerve to serratusNerve to serratus
anterioranterior
Nerve to subclaviusNerve to subclavius
SuprascapularSuprascapular
nervenerve

33. 3333
SUPERFICIAL CERVICAL ARTERY
It is a branch of
the thyrocervical
trunk, of the first
part of the
subclavian artery.
It runs across the
lower part of the
posterior triangle
and disappears
deep to the
trapezius muscle.

34. 3434
SUPASCAPULAR ARTERY
The suprascapular
artery is also a
branch of the
thyrocervical trunk.
It runs across the
lower part of the
posterior triangle.
It follows the
suprascapular nerve
into the supraspinous
fossa and takes part
in the anastomosis
around the scapula.

35. Supraclavicular lymph nodesSupraclavicular lymph nodes
In relation withIn relation with
inferior belly ofinferior belly of
omohyoidomohyoid
Drain lymph fromDrain lymph from
back of scalp, neckback of scalp, neck
and from upperand from upper
deep cervical,deep cervical,
axillary nodesaxillary nodes
Empty into theEmpty into the
jugular lymphjugular lymph
trunktrunk

36. Clinical anatomyClinical anatomy
Subclavian steal syndromeSubclavian steal syndrome

37. Cervical ribCervical rib

38. Swellings in the posteriorSwellings in the posterior
trianglestriangles
Tuberculosis of cervical vertebraTuberculosis of cervical vertebra
Enlarged supraclavicular lymphEnlarged supraclavicular lymph
nodes (Virchow's nodes) as seen innodes (Virchow's nodes) as seen in
many infections like TB, Lymphoma,many infections like TB, Lymphoma,
malignancies of breast, stomach,malignancies of breast, stomach,
testis and other abdominal organstestis and other abdominal organs

39. External jugular veinExternal jugular vein
Injury to EJV in theInjury to EJV in the
supraclavicularsupraclavicular
space cause airspace cause air
embolism andembolism and
sudden death.sudden death.
JVPJVP
Raised in rightRaised in right
sided heart failuresided heart failure

41. THANK YOUTHANK YOU