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M1 - Anatomy

Posterior and Anterior Triangles of the Neck

Jeff DupreeSanger 9-057828-9536jldupree@vcu.edu

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Landmarks of the Neck

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Landmarks of Cervical Triangles

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Anterior Cervical Triangle

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Anterior Cervical Triangle Boundaries

Sup: mandible

Ant: midline

Lat. Post: SCM

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Anterior cervical triangleis divided into 4 smaller triangles

Muscular

Carotid

Submandibular

Submental

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Muscular triangle boundaries

Lat/sup: sup bellyof omohyoid

Lat/inf: SCM

Med/ant: midline

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Muscles in the muscular triangle are referred to asinfrahyoid orstrap muscles

Sup belly of omohyoidSternohyoid

ThyrohyoidSternothyroid

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2 layers:#1 omohyoid

sternohyoid

#2 thyrohyoidsternothyroid

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Innervation of Infrahyoid/Strap Muscles

Ansa cervicalisC1-C3

Exception:Thyrohyoidfibers directly from C1

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Nerves of the Muscular Triangle

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Sup: post belly digastric

Ant: sup belly omohyoid

Post: SCM

Carotid triangle boundaries

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Contents:

Carotid sheathcommon carotidinternal jugularvagus nerve

Ansa cervicalis(embedded in sheath)

Hypoglossal nerve (XII)

Arteries:Branches of

ext. carotid

Carotid triangle

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Contents of carotid sheath

Med: common carotid

Lat: internal jugular

Post: vagus (CN X)

Ansa cervicalisfrequently is embeddedwithin the sheath

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Carotid Triangle

Carotid sinus-dilatation of internal carotid-innervated by CN IX-baroreceptor that reacts to changes in blood pressure

Carotid body-ovoid mass positioned in the bifurcation of the carotid-innervated by CN IX-chemoreceptor that monitors blood oxygen levels

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Sup. ThyroidAscending pharyngealLingualFacialOccipital

NOT in Carotid TrianglePost. AuricularMaxillarySuperficial temporal

Branches of external carotid

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Nerves of Carotid Triangle

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Submandibular triangle boundaries

Sup: mandible

Post/inf: post. digastric

Ant/inf: ant. digastric

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Arteries: facial

Nerve: TrigeminalHypoglossal

Muscles: MylohyoidStylohyoid

Gland: submandibular

Submandibular Triangle contents

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Muscles of the Submandibular Triangle

Posterior belly of digastric CNVIIAnterior belly of digastric CN VMylohyoid CN VStylohyoid CN VII

Suprahyoid muscles-act to elevate the hyoid-if the hyoid bone is stabilized by

the infrahyoid m, can act toopen the mouth

**Geniohyoid C1 via CN XII24

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Submandibular Gland Innervation

Parasympathetic Innervation (secretomotor)

Superior salivatory nucleus Nervus Intermedius (VII)

Chorda tympani (petrotympanic fissure) Lingual n. (V)

submandibular ganglion (post syn.) Submandibular Gland

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Submental Triangle Boundaries

Sup: ant. bellies of digastrics

Inf: hyoid bone

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Submental Triangle Contents

Muscle: mylohyoid

Venous supply:Small veins that

form ant. jugular

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Summary of Anterior Cervical Triangle

Boundaries:Mandible, SCM, midline

Divided into 4 triangles:Muscular, carotid, submandibular, submental

Muscular: infrahyoid muscles innervated by ansa cervicalisEXCEPT thyrohyoid (C1)

Carotid: carotid sheath, ansa cervicalis, branches of ext. carotid,hypoglossal n.

Submandibular: submandibular gland, suprahyoid muscles

Submental: crosses midline

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Landmarks of the Neck

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Posterior Cervical Triangle

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Posterior Cervical Triangle

Subdivided into 2 triangles:

Occipital Supraclavicular (Subclavian)

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Occipital Triangle Boundaries

Ant: SCMInf: inf. belly omohyoidPos: trapezius

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Occipital Triangle

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Occipital Triangle

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Boundaries of the Supraclavicular Triangle

Ant: SCMInf: clavicle Sup/Pos.: inf. belly

omohyoid

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Summary of Posterior Cervical Triangle

2 triangles:occipitalsupraclavicular

Occipital:4 cutaneous nerveslesser occipital, great auricular, transverse cervical, supraclavicular