Triangles of the neck ppt year 1

1. TRIANGLES OF THE NECK

2. •The side of the neck presents a somewhat
quadrilateral outline .
•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 ,it is limited by the upper border of
the clavicle.
•Medially ,by the midline of the neck.
•Posteriorly , by the anterior border of the
Trapezius muscle .

3. Quadrilateral outline in the neck

4. The Sternocleidomastoid muscle

5. •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 .

6. Anterior and posterior triangles

7. Anterior Triangle

8. Posterior triangle

9. Posterior triangle
•This is formed by :
•The Sternocleidomastoid musc.,anteriorly.
•The Trapezius muscle, posteriorly.
•The Clavicle ,inferiorly.
•The apex of the triangle is formed by the
occipital bone.

10. The ROOF of the posterior triangle is
formed by:
•Skin
•Superficial fascia
•Platysma muscle
•Investing layer of the deep cervical fascia

11. The FLOOR of the triangle is formed by
the following muscles from above
downwards:
Splenius Capitis
Levator scapulae
Posterior scalene
Middle scalene
Anterior scalene

12. Subdivisions of the posterior
triangle
•The posterior triangle
is further divided into
two smaller triangles
by the Inferior belly
of the Omohyoid
muscle .
•These are the :
Supraclavicular
triangle
Occipital triangle

13. Supraclavicular triangle
•It is formed by the

Inferior belly of the Omohyoid ,
the Clavicle ,
Sternocleidomastoid muscle.

14. The Occipital triangle
•The Occipital triangle is formed by the
Inferior belly of the Omohyoid
The Trapezius muscle
Sternocleidomastoid muscle.

15. CONTENTS OF THE POSTERIOR
TRIANGLE
•NERVES and PLEXUSES :
•Spinal acessory nerve.
•Branches of Cervical plexus
•Roots and trunks of brachial plexus.

16. Contents of the posterior triangle

18. •VESSELS:
•Subclavian artery
•Transverse Cervical artery
•Suprascapular artery
•External jugular vein (terminal part)

19. LYMPH NODES:
•Occipital
•Supraclavicular
MUSCLES:
•Inferior belly of Omohyoid muscle

20. 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.

21. THE ANTERIOR
TRIANGLE

22. ANTERIOR TRIANGLE
•BOUNDARIES:
Anterior border of the SCM muscle
midline of the neck
inferior border of the mandible
•ROOF:
•Skin
•Superfacial fascia and platysma muscle
•Investing layer of deep cervical fascia

23. SUBDIVISIONS OF ANTERIOR
TRIANGLE

24. SUBDIVISIONS OF THE
ANTERIOR TRIANGLE
•The anterior triangle is divided into four
smaller triangles:
2.SUBMENTAL TRIANGLE
3.SUBMANDIBULAR TRIANGLE
4.CAROTID TRIANGLE
5.MUSCULAR TRIANGLE

25. SUBMENTAL TRIANGLE
•Formed by the :
anterior midline of
neck
hyoid bone
anterior belly of
digastric muscle

26. SUBMANDIBULAR TRIANGLE
•Formed by:
Inferior border of
the mandible
Anterior belly of
the digastric muscle
Posterior belly of
the digastric muscle

27. CAROTID TRIANGLE
•FORMED BY:
Superior belly of the
Omohyoid muscle
Sternocleidomastoid
muscle
Posterior belly of the
digastric muscle

28. MUSCULAR TRIANGLE
•Formed by:
midline of the neck
superior belly of the
Omohyoid
sternocleidomastoid
muscle

29. Contents of the anterior triangle

30. CONTENTS OF THE ANTERIOR
TRIANGLE
•VESSELS:
carotid system(CCA,ICA, ECA)
Internal Jugular vein
•NERVES:
Cranial nerves 7,9,10,11,12
Cervical plexus

32. •MUSCLES:
Suprahyoid muscles: (Digastric ,
Mylohyoid,Stylohyoid,Geniohyoid )These
elevate the hyoid bone , and the floor of
the mouth ,and depress the mandible .

Infrahyoid muscles :
(Sternohyoid,Sternothyroid,Thyrohyoid,
Omohyoid )
These depress the hyoid bone and the
larynx.

33. That’s it!