Dissection 9 - Neck II

Dissection Guide

Osteology

• Important bones… Hyoid, Clavicle, Sternum

  • Sternal angle: Between body of sternum and manubrium

Submandibular Triangle

• Borders: Mandible, anterior digastric, posterior digastric

• Contains submandibular gland

  • Facial a. passes through cleft in gland to get to the face

  • Facial v. lies superficial to gland

• Anterior and posterior belly of digastric have different innervations

  • Anterior: CN V3 (n. to mylohyoid)

  • Posterior: CN VII

• Stylohyoid runs from styloid process to hyoid bone

  • Splits and wraps around digastric tendon to reach hyoid bone

  • Innervated by CN VII

• Hypoglossal n. passes deep to…stylohyoid, mylohyoid, and posterior belly of digastric

• Muscles under mylohyoid

  • Geniohyoid

  • Hyoglossus, superior fibers interdigitate with styloglossus

• Submandibular duct runs superior to hyoglossus

• Lingual n. superior to submandibular duct

  • Sharp cure to reach tongue

  • Submandibular ganglion immediately inferior to lingual n. curve

• Lingual a. passes deep to hyoglossus m. after branching from ECA

Posterior triangle

• Borders: SCM, trapezius, clavicle

• Structures located lateral to IJV

• Vessels in the area

  • R and L brachiocephalic v.

  • Internal jugular v.: Drains into brachiocephalic v.

  • R and L common carotid a.

  • R and L subclavian a. and v.

    • R subclavian a., branches off brachiocephalic trunk

    • L subclavian a. branches directly off aortic arch

• Anterior scale m. found lateral to CCA

  • 2 a. that pass mediolaterally, transverse cervical a. and suprascapular a. (coming off thyrocervical trunk)

    • Inferior thyroid a. goes superiorly to thyroid gland (also a branch)

  • Phrenic n. courses vertically on surface

    • Note that vagus runs medially

• L and R subclavian a. fist branch on either side = vertebral a.

• Thoracic duct enters junction between IJV and L subclavian

Bolded Terms

Anterior and posterior bellies of the digastric m.

• Involved in jaw depression

• Have a tendon connecting the anterior and posterior bellies

• Anterior innervated by CN V3 (n. to mylohyoid)

• Posterior innervated by CN VII

Anterior scalene m.

• Located lateral to CCA

• Phrenic n. runs on top

Brachiocephalic trunk

• Right most branch off aortic arch

• Branches into R CCA and R subclavian a.

Cervical sympathetic trunk

• Paired sympathetic trunk that runs up to base of skull

• Path for sympathetics to travel

Clavicle

• Major site for m. attachment

• Articulates with manubium and scapula

Dens

• Part of C2 vertebrae

Facial a.

• Branch of ECA

• Tortuous as it enters the face around the mandible

Foramen magnum

• Where vertebral a., spinal cord enter brain

Geniohyoid

• Right below mylohyoid

• Run from genu to hyoid

• Suprahyoid m.

Hyoglossus

• Extrinsic tongue m.

• Innervated by CN XII

Hyoid

• Floating bone, kept in place by muscles

Hypoglossal n. (CN XII)

• Provides SM to various tongue m.

Inferior thyroid a.

• Part of thyrocervical trunk

• Ascends to thyroid

Internal jugular v.

• Deep to SCM within carotid sheath

• Drains into brachiocephalic v.

Lingual a.

• Branch of ECA

Lingual n.

• Branch of CN V3

• Found between IAN and long buccal

Manubrium

• Top portion of sternum

Mylohyoid m.

• "Outermost” layer of suprahyoid m.

Mylohyoid n.

• Branch of CN V3

• Provides SM to mylohyoid and anterior belly of digastric

Mylohyoid raphe

• Division between the L and R side of mylohyoid

Phrenic n.

• Originates from C3-5 of cervical plexus

• Runs superficial to anterior scalene m

Posterior triangle

• Bordered by SCM, Trapezius, and Clavicle

Brachiocephalic v.

• Drain into SVC

Common carotid a.

Subclavian v.

• Drain into brachipcephalic v.

Recurrent laryngeal n.

• R recurrent laryngeal loops under R subclavian

• L recurrent laryngeal loops under ligamentum arteriosum

• Provides SS, SM, and parasympathetics to infraglottic area

Retropharyngelal space

• Posterior to the pharynx and esophagus and anterior to the prevertebral muscles

Sternal angle

• Between manubrium and body

Sternal body

• Below manubrium

Sternum

Styloglossus

• Styloid to tongue

• Involved in retraction and elevation of the tongue

Stylohyoid

• Styloid to hyoid

• Splits around digastric tendon

Subclavian a

Submandibular duct

• Courses on the hypoglossal m.

Submandibular gland

Submandibular ganglion

• Submandibular ganglion immediately inferior to lingual n. curve

• Para/pre to submandibular and sublingual glands synapse here

Suprascapular a.

• Most lateral branch off the thyrocervical trunk

Thoracic duct

• Empties into junction between L IJV and brachiocephalic v

• Lymph from whole body except R quadrant

Thyrocervical trunk

• Branch off subclavian a.

Transverse cervial a.

• Branch off thyrocervical trunk

• Courses laterally across anterior scalene m.

Vagus n.

• Courses medially to phrenic n.

• Runs through carotid sheath

Vertebral a.

• First branch on L and R subclavian a,

Xiphoid process

• Bottom of sternum