1. Dr. Juveria Majeed MS ENT, Govt. ENT Hospital/Osmania Medical
College TRIANGLES OF NECK 1 2. The side of the neck is roughly
quadrilateral in outline. It is bounded Anteriorly by Anterior
Median Line Posteriorly- Anterior border of Trapezius Superiorly-
Base of the Mandible, a line joining angle of the mandible &
mastoid process, superior nuchal line. Inferiorly- Clavicle This
quadrangular space is divided obliquely by SCM muscle into anterior
and2 3. STERNOCLEIDOMASTOID Origin: a) Sternal head b) Clavicular
head Insertion: a) Lateral process of mastoid process b) Lateral
half of the superior nuchal line of occipital bone Nerve Supply:
Spinal Accessory Nerve Blood Supply: One br from sup thyroid A. and
suprascapular A. Two br from occipital A. 3 4. STERNOCLEIDOMASTOID
4 One of the most important landmark in neck. Actions- When one
muscles contracts- When both muscles contracts To make scm taut on
one side, the pt is asked to turn the head to opp. side against
resistance. 5. Layers of the Neck 5 Skin Superficial fascia Deep
fascia (Fascia Colli) Deep Structures a) lying above the hyoid bone
b) lying below the hyoid bone 6. SKIN 6 Loosely attached
anteriorly. Posteriorly, the skin is very thick and adherent to the
underlying structures with numerous sebaceous glands. Well supplied
with blood vessels and has transverse lines. Nerve supply: 2nd 3rd
4th cervical nerves. Anterolateral part: anterior primary rami thru
ant. cutaneous, great auricular, lesser occipital and
supraclavicular nerves. Posterior part supplied by dorsal posterior
primary rami. 7. Skin, subcutnaeous fat, superficial fascia
containing platysma, deep fascia 7 8. PLATYSMA 8 It is a
subcutaneous muscle forming a wide, thin fleshy sheet running
upwards and medially in the neck from deltoid and pectoral fasciae
to the base of mandible. Supplied by cervical br. of facial nerve.
9. DEEP FASCIA (FASCIA COLLI) 9 Investing Layer Pretracheal Fascia
Prevertebral fascia Carotid sheath Buccopharyngeal Fascia
Pharyngobasilar Fascia 10. DEEP FASCIA 10 11. Anterior Triangle of
Neck 11 Boundaries: Medially: Ant median plane of neck Laterally:
SCM Superiorly: Base of the mandible and a line joining the angle
of the mandible n mastoid process Subdivisions: The ant triangle is
subdivided by the digastric belly and sup belly of omohyoid into:
a) Submental b) Digastric c) Carotid and d) Muscular Triangles 12.
ANTERIOR TRIANGLE - SUBDIVISONS 12 13. 13 14. SUPRAHYOID MUSCLES14
15. SUPRAHYOID MUSCLES 15 MUSCLE ORIGIN INSERTION NERVE SUPPLY
DIGASTRIC Anterior belly from digastric fossa Post belly from
mastoid notch Intermediate tendon held by a pulley to hyoid bone
Ant belly by nerve of mylohyoid Post belly by facial nerve
STYLOHYOI D Posterior surface of styloid process Junction of body
and greater cornua of hyoid bone Facial nerve MYLOHYOID Mylohyoid
line of mandible Body of hyoid bone Two m. muscle of both side form
median raphe Nerve to mylohyoid GENIOHYOI D Inferior mental
spine(Genial tubercle) Ant surface of body of hyoid bone C1 thru
hypoglossal nerve 16. SUBMENTAL TRIANGLE 16 This is a median
triangle. Boundaries: Either side- Anterior belly of corresponding
digastric muscles Base- Body of hyoid bone Apex- at the chin Floor-
Rt and Lt Mylohyoid muscle 17. CONTENTS OF SUBMENTAL TRIANGLE 17 It
contains: one or two lymph glands, the submental lymph nodes some
small veins; the latter unite to form the anterior jugular vein The
lymph nodes of the submental triangle receive lymph from the skin
of the chin, the lower lip, the floor of the mouth, and the tip of
the tongue. They send lymph to the submandibular and jugular chains
of nodes. They belong to Level 1 gr of LNs 18. DIGASTRIC TRIANGLE
18 The submandibular triangle (or submaxillary or digastric
triangle) corresponds to the region of the neck immediately beneath
the body of the mandible. Boundaries: Anteroinf: Ant belly of
digastric Posteroinf: Post belly of digastric and stylohyoid.
Superiorly: Base of the mandible. Roof : Skin, superficial fascia
with platysma muscle, deep fascia 19. Floor of digastric triangle
19 20. CONTENTS OF DIGASTRIC TRIANGLE 20 ANTERIOR PART OF TRIANGLE
Strucures superficial to mylohyoid are:Superficial part of
submandibular gland, Facial vein , Subman. LN (belong to Level 1 gr
of LNs), Facial A.,Submental A., Mylohyoid nerve and vessels.
Structures superficial to hyoglossus: Subman.gland,Intermedia te
tendon of digastric and 21. CONTENTS OF DIGASTRIC TRIANGLE 21
POSTERIOR PART OF TRIANGLE: Superficial Structures: Lower part of
parotid, ECA before it enters parotid. Deep structures:
Styloglossus, stylopharyngeus, glossopharyngeal N, Pharyngeal br of
vagus, Styloid process, a part of parotid 22. CONTENTS OF POSTERIOR
PART OF DIGASTRIC TRIANGLE 22 Deepest structures: a) Internal
carotid A. b) Internal jugular vein c) Vagus N. Submandibular LNs:
Belong to Level 1 gr of LNs Clinically important because of their
wide area of drainage. They are very commonly enlarged. They drain:
a) center of forehead b) Nose with Max. Frontal & Ethmoid
sinuses c) Inner canthus of the eye d) Upper lip and the ant part
of cheek with adjoinin gums e)Outer part of lower lip with gums and
teeth excluding incisors f)Ant 2/3rd of tongue and floor of mouth
23. CAROTID TRIANGLE 23 Boundaries: Anterosup: Post belly of
digastric Anteroinf: Sup belly of omohyoid Posteriorly: Ant border
of SCM Roof: skin, superficial fascia, investing layer of deep
fascia Floor: Thyrohyoid M, hyoglossus, Middle and Inf.
constrictors of pharynx 24. CONTENTS OF CAROTID TRIANGLE 24
ARTERIES: Common caortid A. with carotid sinus and carotid body at
its termination Internal carotid A. External carotid A. with br.-
Ant br-sup thyroid, lingual facial Post br- Occipital , post.
Auricular Medial- Asc. Pharyngeal Terminal Maxillary , Superficial
Temporal. 25. CAROTID SINUS AND BODY 25 26. BRANCHES OF EXT.CAROTID
ARTERY 26 27. CONTENTS OF CAROTID TRIANGLE 27 VEINS: Internal
Jugular V. Common Facial V. Pharyngeal V Lingual V. all draining in
to internal jugular vein directly or via facial vein 28. CONTENTS
OF CAROTID TRIANGLE 28 NERVES: Vagus running vertically downwards
Sup L.N of vagus dividing into ext n int L.N Spinal Accessory N
Hypoglossal N Sympathetic chain Carotid sheath and its contents
Lymph Nodes: Jugulo- digastric and jugulo- omohyoid 29. CONTENTS OF
CAROTID TRIANGLE ACCESSORY N. HYPOGLOSSAL N. 29 30. ANSA CERVICALIS
30 Also known as Ansa Hypoglossi. This is a thin nerve loop that
lies embedded in the ant wall of carotid sheath. FORMATION:
Superior Root:continuation of descending br of hypoglossal N.
Inferior Root: 2nd and 3rd cervical spinal N. Supplies Infrahyoid
muscles. 31. MUSCULAR TRIANGLE 31 Also known as inferior carotid
triangle. Boundaries: Anteriorly: ant median line of neck
Posterosup: Sup belly of omohyoid Posteroinf: Ant border od SCM
Contents: Infra hyoid Muscles are the chief contents of this
triangle.They also form the floor of the triangle 32. Infrahyoid /
Strap / Ribbon muscles32 33. INFRAHYOID MUSCLES 33 Muscle Origin
Insertion Innervation Sternohyoid Post surface of manubrium sterni
Medial part of lower border of hyoid bone Ansa cervicalis
Sternothyr oid -Post surface of manubrium sterni Oblique line on
lamina of thyroid cartilage Ansa cervicalis Thyrohyoid Oblique line
on lamina of thyroid cartilage Body and greater cornua of hyoid
bone C1 thru hypoglossal N Omohyoid Sup and inf bellies Upper
border of scapula near suprasternal notch Lower border of body of
hyoid bone Ansa cervicalis 34. POSTERIOR TRIANGLE 34 The boundaries
are: Anterior: Post. Border of SCM Posterior: ant border of the
trapezius muscle (Fig. 1-21) Inferior or Base: Middle 1/3rd of
clavicle Apex: Lies on the sup nuchal line where scm and trapezius
meet. Roof: Investing layer of the deep cervical fascia, ext
jugular vein 35. ROOF OF POSTERIOR TRIANGLE35 36. FLOOR OF
POSTERIOR TRIANGLE36 Floor: prevertebral layer of deep cervical
fascia, covering following muscles a) Splenius capitus muscle, b)
Levator scapulae c) Scalenus medius d) Occassionally scalenus
posterior 37. Subdivisions of posterior triangle of neck 37
Subdivided by inf. belly of the omohyoid into a) Larger upper
triangle- Occipital triangle b) Smaller lower triangle-
Supraclavicular or Subclavian triangle 38. TRIANGLE 38 Nerves
Accessory nerve Root, trunks of brachial plexus and their branches
: Nerves to rhomboideus(dorsal scapular n) Nerves to serratus
anterior(long thoracic n) Nerves to subclavius Suprascapular nerve
Cervical nerves Greater occipital nerve Great auriclular nerve
Lesser occipital nerve Transverse cervical nerve of neck
Supraclavicular nerve 3rd and 4th cervical nerves supplying
trapezius 39. NERVES OF POSTERIOR TRIANGLE39 40. ARTERIES OF
POSTERIOR TRIANGLE 40 Arteries Occipital artery Third part of
subclavianartery & branches of subclavianartery Suprascapular
Transverse cervical 41. VEINS IN POSTERIOR TRIANGLE 41 Lower part
of External jugular vein & its tributaries Superficial cervical
vein Subclavian vein is lower down and not in the triangle 42.
LYMPH NODES OF POSTERIOR TRIANGLE 42 Supraclavicularl ymph nodes
are present on posteriorborder of sternocleidomas toid Occipital
nodes The nodes of posterior triangle belong to 5th level of 43.
Levels of lymph nodes 43 Level I: Ia-Submentalgroup
Ib-Submandibulargroup Level II: around upper third of IJV
&adjacent to SAN IIa-located anteriorlyto SAN IIb-located
posteriorlyto SAN Level III: around middle third of IJV Level IV:
around lower third of IJV Level V (posterior triangle group):spinal
accessory nodes, nodes around transverse cervical vessels &
supraclavicular node Level VI: pre & paratracheal, precricoid
& those around reccurent laryngeal nerves Level VIII:
Mediastinal Lymph nodes 44. 44 45. 45
