Pharynx, Larynx & Neck

1 May 2008

Organization of the Neck

Atlas & axis

· Specialized for support and mobility of skull

· Dens - note its position relative to the Atlas

Dens (odontoid process)

· Lateral masses

· Spinous process

· Articular facets

· Lateral masses

· Anterior & posterior arches

· Alar & apical ligaments

· Transverse ligament & synovial cavities

Netter, 2003, pl. 15, 18; Netter, 2006, pl. 17, 22

· Posterior longitudinal ligament

· Tectorial membrane

· Cruciform ligament

– transverse ligament

– superior & inferior bands

Netter, 2003 pl. 18; Netter, 2006 pl. 22

Axis of cranial rotation runs through odontoid process

Moore & Dalley, 1999; Fig. 4-18

Netter, 2003 pl. 17; Netter, 2006 pl. 21

Fascial Sheaths of Neck

· Investing fascia

– Forms complete collar around neck

· Pretracheal fascia

– Contains neck viscera

· Prevertebral fascia

– Covers neuromuscular structures

· Carotid sheath

– Contains carotid a., jugular v., & vagus n.

Anderson 1983, Grant's Atlas of Anatomy, 8th ed; Fig. 9.1C, 9.3C

Netter, 2003 pl. 31; Netter, 2006 pl. 35

Muscles of Neck - superficial

· Trapezius

· Sternocleidomastoid

· Scalenes

· omohyoid

· Digastricus

· Hyoid bone

Netter, 2003 pl. 23; Netter, 2006 pl. 27

Infrahyoid Strap muscles

Named for attachments - inferior to superior

Longest muscles are most superficial

· Sternohyoid

· Omohyoid

· Sternothyroid

· Thyrohyoid

Netter, 2003, pl. 25; Netter, 2006 pl. 29

Suboccipital Muscles

Obliquus capitis sup.

Rectus capitis post. minor

Rectus capitis post. major

Obliquus capitis inf.

Greater occipital n. (sensory)

Suboccipital n. (motor)

Clemente 1997, Fig. 638

Netter, 2003 pl. 168, 171; Netter, 2006 pl. 175, 178

Cervical Plexus

· Hypoglossal n. (CN XII) (not part of cervical plexus)

· Great auricular n

· Lesser occipital n

· Accessory n (CN XI)

· Phrenic n (C 3, 4 &5)

· Vagus n

· Ansa cervicalis - derived from C1,C2, C3

Netter, 2003 pl. 28; Netter, 2006 pl. 32

Scalenes

· Anterior

· Middle

· posterior

Note position of brachial plexus between anterior & middle scalene

Phrenic nerve originates from C3, 4 & 5 and runs over surface of anterior scalene muscle

Netter, 2003 pl. 26, 29; Netter, 2006 pl. 30, 33

Branches of subclavian a.

· Vertebral a.

· Thyrocervical trunk

– suprascapular

– transverse cervical

– inferior thyroid

– ascending cervical a.

Netter, 2003 pl. 29; Netter, 2006 pl. 33

Thyroid gland

· Produces thyroid hormone

· Anterior surface of neck, deep to strap muscles.

· Positioned inferior to thyroid cartilage and contained within pretracheal fascia

Blood supply

· Superior thyroid a.

· Inferior thyroid a.

Thyroid veins

· superior

· middle

· inferior

Netter 1997, pl. 68; 2003, pl. 70

Pharyngeal Musculature (posterior view)

· Superior Constrictor

– Hangs from base of skull

· Stylopharyngeus

· Middle Constrictor

– lateral fibers of the middle pharyngeal constrictor converge on the horn of the hyoid

· Inferior Constrictor

– Cricopharyngeus

Continuous with muscles of esophagus

Rosse & Gaddum-Rosse 1997, Fig. 34-2

Netter, 2003 pl. 63; Netter, 2006 pl. 67

Pharyngeal Musculature (lateral view)

· Tensor veli palatini

· Levator veli palatini

Visible superiorly

Buccinator and Superior Constrictor meet at the Pterygomandibular raphe

Netter, 2003 pl. 64; Netter, 2006 pl. 68

Blood supply and Innervation

· Glossopharyngeal n.

– mostly sensory

· Vagus n.(pharyngeal branch)

– sensory and motor

· Ascending pharyngeal a.

· Tonsillar branches of Facial and Ascending Palatine aa.

· Superior thyroid a.

· Inferior thyroid a.

Rosse & Gaddum-Rosse 1997, Fig. 34-1

See Netter, 2003 pl. 65, 67; Netter, 2006 pl. 69 71

Sagittal section

· Tongue

· Epiglottis

· Aryepiglottic fold

· Vestibular fold

· Ventricle

· Vocal fold

see Netter, 2003 pl. 59; Netter, 2006 pl. 63

Sensory Innervation

Glossopharyngeal superiorly and Vagus inferiorly

see Netter, 2003, pl. 58; Netter, 2006, pl. 62

Laryngeal cartilages

· Thyroid

– Large, shield-shaped, but not a complete ring

· Cricoid

– Complete ring, broader posteriorly, inferior to thyroid

· Arytenoid

– Small paired cartilages; articulate with cricoid

· Epiglottic cartilage

– Supports epiglottis

· Hyoid bone

Not part of larynx; horseshoe-shaped bone; supports the thyohyoid membrane

Netter, 2003 pl. 73; Netter, 2006 pl. 77

Laryngeal cartilages (coronal section)

· Vestibule

· Vestibular fold

– vestibular lig.

· Ventricle

· Vocal fold

– vocal ligament

· Vocalis m.

· Conus elasticus

· Lateral Cricoarytenoid m.

· Cricothyroid m

Netter, 2003 pl. 73; Netter, 2006 pl. 77

Laryngeal Cartilages & the Hyoid Bone

· Thyroid

– Large, shield-shaped, but not a complete ring

· Cricoid

– Complete ring, broader posteriorly, inferior to thyroid

· Arytenoid

– Small paired cartilages; articulate with cricoid

· Hyoid bone

– Not part of larynx; horseshoe-shaped bone

Netter, 2003 pl. 73; Netter, 2006 pl. 77

Larynx (coronal section)

· Vestibule

· Vestibular fold

· Vestibular ligament

· Vocalis m.

· Conus elasticus

· Lateral cricoarytenoid m.

· Cricothyroid m.

Netter, 2003, pl. 74; Netter, 2006 pl. 78

Musculature of Larynx (lateral view)

· transverse arytenoid

· lateral cricoarytenoid

· oblique arytenoid

· aryepiglottic

· thyroarytenoid

Netter, 2003, pl. 74; Netter, 2006 pl. 78

Action of Cricothyroid muscles

· Increase tension on vocal ligaments

· Pivots on cricothyroid joint

Netter, 2003 pl. 75; Netter, 2006 pl. 79

Action of Posterior & Lateral Cricoarytenoids

· Posterior cricoarytenoids

· abduct vocal ligaments

· Lateral cricoarytenoids

· adduct vocal ligaments

Netter, 2003 pl. 75; Netter, 2006 pl. 79

Vocalis

· Regulate tension on vocal ligaments

Laryngeal Innervation

· Superior laryngeal nerve

– internal & external branches

· Recurrent laryngeal nerve

Netter, 2003 pl. 76; Netter, 2006 pl. 80

Pharyngeal & Laryngeal

Motor innervations

· CN V - tensor veli palatini; mylohyoid; ant. belly of digastric

· CN IX - stylopharyngeus

· CN X - all pharyngeal constrictors; Levator veli palatini; all muscles of larynx; palatoglossus

· CN XII - all muscles of tongue except palatoglossus

Cranial Nerves IX, X, XI, XII - note relationship of these nerves to the posterior wall of the

pharynx IX, X and XI all emerge from the jugular foramen.

XII emerges from the hypoglossal canal.