TRIANGLES OF NECK
TRIANGLES OF NECK
TRIANGLES OF NECK
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STERNOCLEIDO-<br />
MASTOID<br />
<strong>TRIANGLES</strong> <strong>OF</strong> <strong>NECK</strong><br />
OUTLINE<br />
I. <strong>TRIANGLES</strong> <strong>OF</strong><br />
<strong>NECK</strong><br />
II. DEEP<br />
STRUCTURES <strong>OF</strong><br />
<strong>NECK</strong><br />
TO LOCATE STRUCTURES IN <strong>NECK</strong> ON PATIENT OR<br />
IN PRACTICAL EXAM MOST USEFUL LANDMARK<br />
IS STERNOCLEIDOMASTOID MUSCLE
Sternocleidomastoid<br />
Muscle<br />
Posterior<br />
triangle<br />
I. <strong>TRIANGLES</strong> <strong>OF</strong> <strong>NECK</strong><br />
Anterior<br />
triangle<br />
Triangles of Neck –<br />
for description neck<br />
is divided into<br />
anterior & posterior<br />
triangles by<br />
Sternocleidomastoid<br />
muscle
Anterior -<br />
Sternocleidomastoid<br />
Muscle<br />
Posterior<br />
Trapezius<br />
A. POSTERIOR TRIANGLE<br />
Clavicle<br />
1. Boundaries<br />
Superficial cover<br />
- superficial<br />
fascia, platysma<br />
and Investing<br />
Layer<br />
Deep - (floor)<br />
Prevertebral<br />
layer of fascia
Occipital<br />
artery<br />
Supraclavicular<br />
nerves<br />
B. CONTENTS <strong>OF</strong> POSTERIOR TRIANGLE<br />
Great<br />
Auricular n.<br />
Lesser<br />
occipital n.<br />
Accessory n.<br />
(XI)<br />
Superficial -<br />
branches of<br />
cervical<br />
plexus<br />
Trans Cerv. n.<br />
External<br />
Jugular Vein
POSTERIOR TRIANGLE - deeper, saw through<br />
clavicle Nose<br />
Note:<br />
Accessory n. -<br />
divides post.<br />
triangle into<br />
'Carefree' -<br />
superior<br />
'Careful' -<br />
inferior<br />
Brachial<br />
plexus<br />
roots &<br />
trunks<br />
Phrenic<br />
nerve
Brachial<br />
plexus roots &<br />
trunks<br />
Transverse<br />
(superf.)<br />
Cervical A.<br />
Suprascapular<br />
A.<br />
Subclavian a.<br />
POSTERIOR TRIANGLE - deeper<br />
Phrenic n.<br />
Nose<br />
note: Subclavian vein is not in post triangle<br />
Subclavian<br />
vein
B. ANTERIOR TRIANGLE <strong>OF</strong> <strong>NECK</strong><br />
Sternocleidomastoid<br />
Muscle<br />
Midline<br />
of neck<br />
1. Boundariesant.<br />
- midline of neck<br />
post. - sternocleidomastoid<br />
superior - mandible<br />
(lower margin).<br />
Subdivided to<br />
smaller triangles (not<br />
required)
2. CONTENTS <strong>OF</strong> ANTERIOR TRIANGLE <strong>OF</strong> <strong>NECK</strong><br />
In Carotid<br />
sheath:<br />
Int. and<br />
Common<br />
Carotid A.,<br />
Int. Jug. V.,<br />
Vagus N.<br />
Follow<br />
dissection<br />
to all<br />
branches of<br />
Ext. carotid<br />
- cut through<br />
sternocleidomastoid<br />
2”<br />
above<br />
sternum<br />
Hypoglossal<br />
n. XII & ansa<br />
cervicalis
Lateral Lobe<br />
II. DEEP STRUCTURES <strong>OF</strong> <strong>NECK</strong><br />
A. THYROID GLAND<br />
Two Lateral<br />
Lobes - below<br />
& on sides<br />
thyroid<br />
cartilage<br />
Lateral Lobe
Isthmus<br />
- located<br />
below<br />
cricoid<br />
cartilage<br />
Right<br />
lateral<br />
lobe<br />
THYROID GLAND<br />
Left<br />
lateral<br />
lobe<br />
Pyramidal lobewhen<br />
present often<br />
attached to hyoid<br />
bone by fibrous<br />
strand
very<br />
vasculararteries<br />
accompanied<br />
by nerves<br />
THYROID GLAND - ARTERIAL SUPPLY<br />
a) Sup.<br />
Thyroid<br />
artery &<br />
Sup.<br />
Laryngeal n.<br />
b) Inf.<br />
Thyroid<br />
artery &<br />
Recurrent<br />
laryngeal n.<br />
Note: In thyroid surgery care taken not to damage<br />
Recurrent Laryngeal Nerve
THYROID GLAND - LOTS <strong>OF</strong> VEINS<br />
1) Sup. Thyroid vein<br />
follows Sup. Thyroid<br />
artery<br />
2) Middle Thyroid<br />
vein - to Int Jugular<br />
3) Inf. Thyroid vein -<br />
Both sides join at<br />
midline -> L.<br />
Brachiocephalic Vein
Superior<br />
parathyroid<br />
gland<br />
Inferior<br />
parathyroid<br />
gland<br />
PARATHYROID GLANDS<br />
- 4 small<br />
bodies (2<br />
on each<br />
side)<br />
located<br />
posterior<br />
to or<br />
within<br />
Thyroid<br />
gland
Ant to<br />
vertebrae<br />
Not<br />
confuse<br />
with<br />
Vagus X<br />
SYMPATHETIC CHAIN<br />
Sympathetic<br />
trunk- deep to<br />
(not in)<br />
Carotid Sheath<br />
Note: sympathetics<br />
to most of head<br />
are from Superior<br />
Cervical Ganglion
FOLLOWS LEFT<br />
MARGIN <strong>OF</strong><br />
ESOPHAGUS<br />
THORACIC DUCT<br />
INT. JUGULAR V.<br />
THORACIC DUCT<br />
SUBCLAVIAN V.<br />
DRAINS TO LEFT<br />
BRACHIOCEPHALIC<br />
V.<br />
AT JUNCTION <strong>OF</strong><br />
SUBCLAVIAN AND<br />
INT. JUGULAR VEINS
GUIDE TO DISSECTION<br />
1) Completely Skin Neck<br />
2) Skip p. 175 see:<br />
Prosection Cutaneous<br />
nerves<br />
Do Post. Triangle<br />
3) Cut through clavicle if<br />
not already done<br />
4) Cut through<br />
sternocleidomastoid 2”<br />
(5cm) above sternum p.<br />
178
Superficial fascia:<br />
- connective<br />
tissue below<br />
dermis<br />
- completely<br />
surrounds neck -<br />
thin and hard to<br />
demonstrate<br />
- contains<br />
Platysma &<br />
Superficial veins<br />
FASCIA <strong>OF</strong> <strong>NECK</strong>
Occipital<br />
artery<br />
Supraclavicular<br />
nerves<br />
POSTERIOR TRIANGLE - CONTENTS<br />
Great<br />
Auricular n.<br />
Lesser<br />
occipital n.<br />
Accessory n.<br />
(XI)<br />
Superficial -<br />
branches of<br />
cervical<br />
plexus<br />
Trans Cerv. n.<br />
External<br />
Jugular Vein
POSTERIOR TRIANGLE - deeper, saw through<br />
clavicle Nose<br />
Accessory n.divides<br />
post.<br />
triangle into<br />
CarefreesuperiorCarefulinferior<br />
Phrenic<br />
nerve<br />
Brachial<br />
plexus<br />
roots &<br />
trunks
Brachial<br />
plexus roots &<br />
trunks<br />
Transverse<br />
(superf.)<br />
Cervical A.<br />
Suprascapular<br />
A.<br />
Subclavian a.<br />
POSTERIOR TRIANGLE - deeper<br />
Phrenic n.<br />
Nose<br />
note: Subclavian vein is not in post triangle<br />
Subclavian<br />
vein
ANTERIOR TRIANGLE <strong>OF</strong> <strong>NECK</strong> - CONTENTS<br />
Carotid sheath<br />
contents<br />
Int. and<br />
Common<br />
Carotid A.,<br />
Int. Jug. V.,<br />
Vagus N.<br />
Follow<br />
dissection to all<br />
branches of ext.<br />
carotid<br />
-cut through<br />
sternocleido<br />
mastoid 2”<br />
above<br />
sternum<br />
Hypoglossal<br />
n. XII & ansa<br />
cervicalis
Superficial temporalscalp<br />
& temporalis<br />
Post auricular- post. ear &<br />
scalp<br />
Occipital- post.<br />
scalp<br />
EXTERNAL CAROTID ARTERY<br />
Ascending pharyngealpharynx<br />
Maxillary<br />
Facial<br />
Lingual- tongue<br />
Superior thyroid- br. is Sup<br />
laryngeal
PROSECTION<br />
<strong>OF</strong><br />
ANTERIOR<br />
<strong>NECK</strong>
INFRAHYOID MUSCLES - all depress hyoid<br />
NOSE<br />
2) STERNOHYOID<br />
O- Manubrium &<br />
clavicle<br />
1) OMOHYOID<br />
intermediate<br />
tendon to<br />
clavicle, rib 1;<br />
Sup. belly to<br />
hyoid<br />
deeper<br />
4) THYROHYOID - O -<br />
thyroid cartilage; also<br />
elevates larynx<br />
3) STERNOTHYROID --<br />
O - manubrium I -<br />
thyroid cartilage; also<br />
depresses larynx
very<br />
vasculararteries<br />
accompanied<br />
by nerves<br />
THYROID GLAND - ARTERIAL SUPPLY<br />
Sup. Thyroid<br />
artery &<br />
Sup.<br />
Laryngeal n.<br />
Inf. Thyroid<br />
artery &<br />
Recurrent<br />
laryngeal n.<br />
Note: in thyroid surgery care taken not to damage<br />
Recurrent Laryngeal Nerve
PROSECTION:<br />
DEEP<br />
DISSECTION <strong>OF</strong><br />
<strong>NECK</strong>
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