Posterior and Anterior Triangles of the Neck
M1 - Anatomy
Posterior and Anterior Triangles of the Neck
Jeff Dupree Sanger 9-057 828-9536 [email protected]
1
Landmarks of the Neck
2 Landmarks of Cervical Triangles
3
Anterior Cervical Triangle
4 Anterior Cervical Triangle Boundaries
Sup: mandible
Ant: midline
Lat. Post: SCM
5
Anterior cervical triangle is divided into 4 smaller triangles
Muscular
Carotid
Submandibular
Submental
6 Muscular triangle boundaries
Lat/sup: sup belly of omohyoid
Lat/inf: SCM
Med/ant: midline
7
8 Muscles in the muscular triangle are referred to as infrahyoid or strap muscles
Sup belly of omohyoid Sternohyoid
Thyrohyoid Sternothyroid
9
2 layers: #1 omohyoid sternohyoid
#2 thyrohyoid sternothyroid
10 Innervation of Infrahyoid/Strap Muscles
Ansa cervicalis C1-C3
Exception: Thyrohyoid fibers directly from C1
11
Nerves of the Muscular Triangle
12 Carotid triangle boundaries
Sup: post belly digastric
Ant: sup belly omohyoid
Post: SCM
13
Carotid triangle
Contents:
Carotid sheath common carotid internal jugular vagus nerve
Ansa cervicalis (embedded in sheath)
Hypoglossal nerve (XII)
Arteries: Branches of ext. carotid 14 Contents of carotid sheath
Ansa cervicalis frequently is embedded within the sheath
Med: common carotid
Lat: internal jugular
Post: vagus (CN X)
15
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
16 17
Branches of external carotid
Sup. Thyroid Ascending pharyngeal Lingual Facial Occipital
NOT in Carotid Triangle Post. Auricular Maxillary Superficial temporal
18 19
Nerves of Carotid Triangle
20 Submandibular triangle boundaries
Sup: mandible
Post/inf: post. digastric
Ant/inf: ant. digastric
21
Submandibular Triangle contents
Arteries: facial
Nerve: Trigeminal Hypoglossal
Muscles: Mylohyoid Stylohyoid
Gland: submandibular 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 27
28 29
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
30 Submental Triangle Boundaries
Sup: ant. bellies of digastrics
Inf: hyoid bone
31
Submental Triangle Contents
Muscle: mylohyoid
Venous supply: Small veins that form ant. jugular
32 Summary of Anterior Cervical Triangle
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
33
Landmarks of the Neck
34 Posterior Cervical Triangle
35
Posterior Cervical Triangle
Subdivided into 2 triangles:
Occipital Supraclavicular (Subclavian)
36 Occipital Triangle Boundaries
Ant: SCM Inf: inf. belly omohyoid Pos: trapezius
37
Occipital Triangle
38 Occipital Triangle
39
40 Boundaries of the Supraclavicular Triangle
Ant: SCM Inf: clavicle Sup/Pos.: inf. belly omohyoid
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42 Summary of Posterior Cervical Triangle
2 triangles: occipital supraclavicular
Occipital: 4 cutaneous nerves lesser occipital, great auricular, transverse cervical, supraclavicular
43