TRIANGLES OF NECK

TO LOCATE STRUCTURES IN NECK ON PATIENT OR IN PRACTICAL EXAM MOST USEFUL LANDMARKIS STERNOCLEIDOMASTOID MUSCLE

OUTLINE

I. TRIANGLES OFNECK

II. DEEPSTRUCTURES OFNECK

STERNOCLEIDO-MASTOID

Triangles of Neck –for description neck is divided into anterior & posterior triangles bySternocleidomastoidmusclePosterior

triangleAnterior triangle

SternocleidomastoidMuscle

I. TRIANGLES OF NECK

1. Boundaries

Superficial cover - superficial fascia, platysmaand Investing Layer

Deep - (floor) Prevertebrallayer of fascia

Clavicle

A. POSTERIOR TRIANGLE

PosteriorTrapezius

Anterior -SternocleidomastoidMuscle

Superficial -branches of cervical plexus

Trans Cerv. n.

External Jugular VeinSupra-

clavicular nerves

Occipital artery

Great Auricular n.

Lesser occipital n.

Accessory n. (XI)

B. CONTENTS OF POSTERIOR TRIANGLE

Note: Accessory n. -divides post. triangle into 'Carefree' -superior 'Careful' -inferior Phrenic

nerveBrachial plexus roots & trunks

POSTERIOR TRIANGLE - deeper, saw throughclavicle Nose

note: Subclavian vein is not in post triangle

Nose

Phrenic n.Brachial plexus roots & trunks

Transverse (superf.) Cervical A.

Suprascapular A.

Subclavian a.Subclavian vein

POSTERIOR TRIANGLE - deeper

1. Boundaries-ant. - midline of neckpost. - sternocleido-mastoid superior - mandible (lower margin).

Subdivided to smaller triangles (not required)

Midline of neck

SternocleidomastoidMuscle

B. ANTERIOR TRIANGLE OF NECK

In Carotid sheath:Int. and Common Carotid A., Int. Jug. V., Vagus N.

Follow dissection to all branches of Ext. carotid

- cut through sternocleido-mastoid 2” above sternum

Hypoglossal n. XII & ansa cervicalis

2. CONTENTS OF ANTERIOR TRIANGLE OF NECK

Two Lateral Lobes - below & on sides thyroid cartilage

Lateral Lobe

A. THYROID GLAND

Lateral Lobe

II. DEEP STRUCTURES OF NECK

THYROID GLAND

Right lateral lobe

Left lateral lobe

Isthmus- located below cricoid cartilage

Pyramidal lobe-when present often attached to hyoid bone by fibrous strand

very vascular-arteries accompanied by nerves

a) Sup. Thyroid artery &Sup. Laryngeal n.

b) Inf. Thyroid artery & Recurrent laryngeal n.

Note: In thyroid surgery care taken not to damage Recurrent Laryngeal Nerve

THYROID GLAND - ARTERIAL SUPPLY

THYROID GLAND - LOTS OF VEINS

1) Sup. Thyroid vein follows Sup. Thyroid artery

2) Middle Thyroid vein - to Int Jugular

3) Inf. Thyroid vein -Both sides join at midline -> L. Brachiocephalic Vein

PARATHYROID GLANDS

- 4 small bodies (2 on each side) located posterior to or within Thyroid gland

Superior parathyroid gland

Inferior parathyroid gland

Sympathetic trunk- deep to (not in) Carotid Sheath

Ant to vertebrae

Not confuse with Vagus X

SYMPATHETIC CHAIN

Note: sympatheticsto most of headare from SuperiorCervical Ganglion

FOLLOWS LEFT MARGIN OF ESOPHAGUS

DRAINS TO LEFT BRACHIOCEPHALIC V.

AT JUNCTION OF SUBCLAVIAN AND INT. JUGULAR VEINS

THORACIC DUCT

SUBCLAVIAN V.

INT. JUGULAR V.

THORACIC DUCT

1) Completely Skin Neck

2) Skip p. 175 see: Prosection Cutaneousnerves

Do Post. Triangle

3) Cut through clavicle if not already done

4) Cut through sternocleidomastoid 2” (5cm) above sternum p. 178

GUIDE TO DISSECTION

Superficial fascia:

- connective tissue below dermis - completely surrounds neck -thin and hard to demonstrate - contains Platysma & Superficial veins

FASCIA OF NECK

Superficial -branches of cervical plexus

Trans Cerv. n.

External Jugular VeinSupra-

clavicular nerves

Occipital artery

Great Auricular n.

Lesser occipital n.

Accessory n. (XI)

POSTERIOR TRIANGLE - CONTENTS

Accessory n.-divides post. triangle into Carefree-superior Careful-inferior Phrenic

nerveBrachial plexus roots & trunks

POSTERIOR TRIANGLE - deeper, saw throughclavicle Nose

note: Subclavian vein is not in post triangle

Nose

Phrenic n.Brachial plexus roots & trunks

Transverse (superf.) Cervical A.

Suprascapular A.

Subclavian a.Subclavian vein

POSTERIOR TRIANGLE - deeper

Carotid sheath contents Int. and Common Carotid A., Int. Jug. V., Vagus N.

Follow dissection to all branches of ext. carotid

-cut through sternocleidomastoid 2” above sternum

Hypoglossal n. XII & ansa cervicalis

ANTERIOR TRIANGLE OF NECK - CONTENTS

Superficial temporal-scalp & temporalis

Post auricular- post. ear & scalp

Occipital- post. scalp

Ascending pharyngeal-pharynx

Lingual- tongue

Superior thyroid- br. is Sup laryngeal

Maxillary

EXTERNAL CAROTID ARTERY

Facial

PROSECTION OFANTERIORNECK

2) STERNOHYOID O- Manubrium & clavicle

1) OMOHYOID intermediate tendon to clavicle, rib 1; Sup. belly to hyoid

4) THYROHYOID - O -thyroid cartilage; also elevates larynx

3) STERNOTHYROID --O - manubrium I -thyroid cartilage; also depresses larynx

INFRAHYOID MUSCLES - all depress hyoid

deeperNOSE

very vascular-arteries accompanied by nerves

Sup. Thyroid artery &Sup. Laryngeal n.

Inf. Thyroid artery & Recurrent laryngeal n.

Note: in thyroid surgery care taken not to damage Recurrent Laryngeal Nerve

THYROID GLAND - ARTERIAL SUPPLY

PROSECTION: DEEPDISSECTION OFNECK