2. Introduction
Anterolaterally
the neck appears
as a quadrilateral
area
It is limited
• Above by the lower border of the
body of the mandible ,and an imaginary
line drawn from the angle of the
mandible to the mastoid process.
• Below , by the upper border of the
clavicle.
• Medially ,by the midline of the neck.
• Posteriorly , by the anterior border of
the trapezius muscle .
3. •This quadrilateral space is
divided by the
Sternocleidomastoid muscle
into two main triangles
•The Sternocleidomastoid
muscle passes obliquely
upwards and backwards
from its site of origin at the
clavicle and sternum to its
point of insertion on the
mastoid process and the
occipital bone
•The triangle in front of this
muscle is the anterior
triangle and the one behind
it is the posterior triangle
4. Anterior Triangle
Boundaries
Anterior border of the
SCM muscle
Midline of the neck
Inferior border of the
mandible
Roof
Skin
Superfacial fascia
Platysma muscle
Investing layer of deep
cervical fascia
5. Posterior triangle
Boundaries
Anteriorly: The
Sternocleidomastoid musc
posteriorly:The Trapezius
muscle.
Inferiorly:The Clavicle
The apex: occipital bone
Roof
Skin
Superficial fascia
Platysma muscle
Investing layer of the deep
cervical fascia
Floor
Splenius Capitis
Levator scapulae
Posterior scalene
Middle scalene
Anterior scalene
11. Submandibular Triangle
Roof
• Platysma
• Facial vein (fv)
• Cervical branch of facial nerve (cbf)
Removal of the superficial
structures displays the
submandibular salivary gland
itself.
12. Contents Of The Submandibular Triangle
Facial
artery
Lingual nerve
and
submandibula
r ganglion
• The lingual nerve and
submandibular duct pass
through a gap between
the hypoglossal (hg) and
mylohyoid (mh) muscles
Submandibul
ar duct
Lingual
artery
• The lingual artery passes
deep to the hyoglossus
muscle
Hypoglossal
nerve
14. Submental Triangle
Formed by the :
Anterior midline of neck
Hyoid bone
Anterior belly of digastric
muscle
Located between the two
anterior digastric muscles
Structures
Submental lymph node-
drain the floor of the
mouth.
Mylohyoid muscle (mh)
arise from the body of the
hyoid bone and insert into
the mylohyoid line of the
inside of the mandible.
16. Carotid Triangle
Boundaries of the carotid
triangle are:
posterior belly of digastric muscle (pbd)
superior belly of the omohyoid muscle (so)
anterior border of sternomastoid muscle
(st)
Roof:
skin
superficial fascia
platysma
17. Carotid Triangle
Deepest aspect of
the carotid
triangle
The muscles, at
this level, are the
middle and lower
pharyngeal
constrictors
Floor
Superior laryngeal
nerve, a branch of
the vagus its 2
terminal branches
Internal laryngeal
(ilb--sensory to
upper part of the
larynx)
External laryngeal
(elb--motor to the
cricoid muscle)
Structures
seen
passing
through
18. Contents Of Carotid Triangle
Veins
• Common facial vein
• Near by:
• Retromandibular vein
• Posterior auricular vein
(pav)
• Facial vein (fv)
• External jugular vein
• Anterior jugular vein
Arteries
• Facial
• Lingual
• Occipital
• Common carotid
• External carotid
• Internal carotid
• Superior thyroid
Nerves
• Hypoglossal (XII)
• C1 root of ansa cervicalis (C1)
• C1 fibers running with
hypoglossal nerve (nerve to
thyrohyoid muscle (nth)
• C2-C3 root of ansa cervicalis
• Ansa cervicalis (ac)
20. Muscular Triangle
Boundaries
• Mid line of neck
• Superior belly of omohyoid
• Sternomastoid
The muscles forming and within the triangle
• Superficial layer
• Sternohyoid (sh)
• Superior belly of omohyoid (oh)
• Deep layer
• Thyroid (th)
• Sternothyroid (st)
Strap
Muscles
21. Muscular Triangle
When the strap muscles are reflected,
you can see the thyroid gland with its
arteries (superior and inferior thyroid
artery)
If the thyroid gland is reflected
laterally, the structures making up the
larynx and trachea are seen:
thyrohyoid membrane (thm)
thyroid cartilage (Adam's apple)(tc)
cricothyroid membrane and ligament
(ctm)
cricoid cartilage (cc)
tracheal rings (tr)
22. Table of Muscles
Muscle Origin Insertion Nerve supply
Sternohyoid Sternum Hyoid Ansa
Omohyoid Suprascapular notch Hyoid Ansa
Sternothyroid
Below sternohyoid on
manubrium
Thyroid cartilage oblique
line
Ansa
Thyrohyoid
Thyroid cartilage oblique
line
Hyoid C1-C2 (ansa)
Anterior belly digastric Intermediate tendon Inner surface of mandile Trigeminal nerve
Posterior belly
Digastric
Medial aspect of the
mastoid process
-Intermediate tendon- Facial nerve
Mylohyoid Mylohyoid line of mandible Hyoid bone Trigeminal nerve
Hyoglossus Hyoid bone Lateral side of tongue Hypoglossal
Stylohyoid Styloid process Hyoid Facial nerve
23. Clinical Considerations
The cricothyroid ligament and membrane are
frequently pierced in emergency situations to open the
airway.
It has been known that an empty ball-point pen or a
hollow stem has been used in the field to save lives,
where an air passage has been closed above this region.
26. Boundaries of Posterior Triangle
Anteri
orly
• Sternocleidomastoid
Poster
iorly
• Anterior edge of trapezius
Inferi
orly
• Middle third of the clavicle
Apex
• Between the attachments of sternocleidomastoid and trapezius to the
occiput and is often blunted, so that the 'triangle' becomes quadrilateral
Roof
• Investing layer of the deep cervical fascia
Floor
• Prevertebral fascia overlying splenius capitis, levator scapulae and the
scalene muscles
27. Nerves And
Plexuses
• Spinal acessory
nerve.
• Branches of
Cervical plexus
• Roots and trunks
of brachial plexus
Vessels
• Subclavian artery
• Transverse
Cervical artery
• Suprascapular
artery
• External jugular
vein (terminal
part)
Lymph Nodes
• Occipital
• Supraclavicular
Muscles
• Inferior belly of
Omohyoid muscle
Contents of the posterior triangle
28. Clinical Significance Of The Posterior Triangle
The Accessory Nerve may be damaged, while
taking lymph node biopsy.
The External Jugular Vein is present in a
superficial location here and this makes it
vulnerable to injury.
29. Lower and smaller
division of the posterior
triangle
It corresponds in the living neck
with the lower part of a deep,
prominent hollow, namely, the
greater supraclavicular fossa
Its size varies with the extent of the clavicular
attachments of sternocleidomastoid and
trapezius and also the level of the inferior belly
of omohyoid
Subclavian Triangle
30. Boundaries
Borders
• It shares the
same
boundaries
• Except that
superiorly it is
limited by
omohyoid
Floor
• The first rib,
• Scalenus
medius
• The first slip
of serratus
anterior
Roof
• Supraclavicular
nerves
• Platysma
• Superficial and
deep fasciae
• Skin
33. Boundaries
Shares the same
borders
Except that
inferiorly by the
inferior belly of
omohyoid
Borders
Semispinalis
capitis
Occasionally
appears at the
apex
Posteriorly
35. Contents
Cutaneous and muscular branches of the
cervical plexus
Uppermost part of the brachial plexus
Transverse cervical vessels
Spinal accessory nerve
Supraclavicular nerves
Lymph nodes
