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M1 - Anatomy
Posterior and Anterior Triangles of the Neck
Jeff DupreeSanger [email protected]
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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