Posterior and Anterior Triangles of the Neck

Home , Carotid triangle, Muscular triangle, Occipital triangle, Submandibular triangle, Submental triangle, Triangles of the neck

Landmarks of the Neck M1 - Anatomy

Jeff Dupree Sanger 9-057 828-9536 [email protected]

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Landmarks of Cervical Triangles Anterior Cervical Triangle

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Anterior Cervical Triangle Boundaries Anterior cervical triangle is divided into 4 smaller triangles Sup: mandible

Ant: midline Muscular

Lat. Post: SCM Carotid

Submandibular

Submental

5 6 Muscular triangle boundaries

Lat/sup: sup belly of omohyoid

Lat/inf: SCM

Med/ant: midline

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Muscles in the muscular triangle are referred to as 2 layers: infrahyoid or #1 omohyoid strap muscles sternohyoid

#2 thyrohyoid Sup belly of omohyoid sternothyroid Sternohyoid

Thyrohyoid Sternothyroid

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Innervation of Infrahyoid/Strap Muscles Nerves of the Muscular Triangle

Ansa cervicalis C1-C3

Exception: Thyrohyoid fibers directly from C1

11 12 Carotid triangle boundaries Carotid triangle Contents:

Sup: post belly digastric Carotid sheath common carotid internal jugular Ant: sup belly omohyoid vagus nerve

Post: SCM Ansa cervicalis (embedded in sheath)

Hypoglossal nerve (XII)

Arteries: Branches of ext. carotid 13 14

Contents of carotid sheath Carotid Triangle

Carotid sinus Ansa cervicalis -dilatation of internal carotid frequently is embedded -innervated by CN IX within the sheath -baroreceptor that reacts to changes in blood pressure

Carotid body Med: common carotid -ovoid mass positioned in the bifurcation of the carotid -innervated by CN IX Lat: internal jugular -chemoreceptor that monitors blood oxygen levels

Post: vagus (CN X)

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Branches of external carotid

Sup. Thyroid Ascending pharyngeal Lingual Facial Occipital

NOT in Carotid Triangle Post. Auricular Maxillary Superficial temporal

17 18 Nerves of Carotid Triangle

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Submandibular triangle boundaries Submandibular Triangle contents Arteries: facial

Sup: mandible Nerve: Post/inf: post. digastric Trigeminal Hypoglossal Ant/inf: ant. digastric Muscles: Mylohyoid Stylohyoid

Gland: submandibular 21 22

Muscles of the Submandibular Triangle

Posterior belly of digastric CNVII Anterior belly of digastric CN V Mylohyoid CN V Stylohyoid CN VII

Suprahyoid muscles -act to elevate the hyoid -if the hyoid bone is stabilized by the infrahyoid m, can act to open the mouth

**Geniohyoid C1 via CN XII 23 24 25 26

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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

29 30 Submental Triangle Contents Submental Triangle Boundaries

Sup: ant. bellies of digastrics Muscle: mylohyoid Inf: hyoid bone Venous supply: Small veins that form ant. jugular

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Summary of Anterior Cervical Triangle Landmarks of the Neck

Boundaries: Mandible, SCM, midline

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

Muscular: infrahyoid muscles innervated by ansa cervicalis EXCEPT 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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Posterior Cervical Triangle Posterior Cervical Triangle

Subdivided into 2 triangles:

Occipital Supraclavicular (Subclavian)

35 36 Occipital Triangle Boundaries Occipital Triangle

Ant: SCM Inf: inf. belly omohyoid Pos: trapezius

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Occipital Triangle

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Boundaries of the Supraclavicular Triangle

Ant: SCM Inf: clavicle Sup/Pos.: inf. belly omohyoid

41 42 Summary of Posterior Cervical Triangle

2 triangles: occipital supraclavicular

Occipital: 4 cutaneous nerves lesser occipital, great auricular, transverse cervical, supraclavicular