L10: Pharynx and larynx

Question 1

Constrictor muscles of pharynx

Answer 1

ALL have inf and ant part missing and have left and right joint at pharyngeal raphe
Superior, middle and inferior constrictor muscles

Question 2

Superior constrictor attachments

Answer 2

• Superiorly attached to base of skull (sphenoid bone, temporal bone, pharyngeal tubercle)
• Anteriorly attached to pterygomandibular raphe (ant to raphe is buccinator in the same plane as sup constrictor)

Question 3

Middle constrictor attachments

Answer 3

Attached to lower part of stylohyoid ligament, lesser horn of hyoid bone and greater horn of hyoid bone

Question 4

Inferior constrictor attachments

Answer 4

• Attached to oblique line on thyroid cartilage (where sternothyroid and thyrohyoid also attach)
• And attached down to cricothyroid muscle and cricoid cartilage

Question 5

Longitudinal muscles

Names and function

Answer 5

1. Salpingopharyngeus (attached to cartilaginous part of stylopharyngeus tube)
2. Palatopharyngeus
3. Stylopharyngeus
   From sites of origin run downwards and attach into pharyngeal wall.

Together with pharyngobasilar fascia (between mucosa and constrictor muscles) stabilises the pharynx
Elevate wall and/or assist in swallowing

Question 6

Gaps in pharyngeal wall

Answer 6

Oropharyngeal triangle:
(post free edge of mylohyoid, inf edge of sup constrictor, sup edge of mid constrictorz0
- Lingual a after branching off ext carotid goes anteriorly into triangle
- Hypoglossal n [XII], glossopharyngeal n [IX]
- Lingual n

Between mid and inf constrictor:
- Internal laryngeal n (branch of sup laryngeal) and vessels enter

Below inferior constrictor:
- Recurrent laryngeal n from [X] and inferior laryngeal vessels enter larynx

Question 7

Pharyngeal tonsil

Answer 7

On roof of nasopharynx is pharyngeal (adenoid) tonsil

Enlarged adenoids –> fill nasopharynx and blocks nasal cavity, can also block Eustachian tube (which goes from nasal cavity to middle ear) –> middle ear infection, cannot breathe through nose, loud breathing

Question 8

Pharynx blood supply and venous drainage

Answer 8

Blood supply:
Upper part - supplied by branches of ext carotid (lingual, maxillary, facial a)
Lower part - branches of subclavian a (inf thyroid a of thyrocervical trunk)

(major blood supply to palatine tonsil is tonsillar branch from facial artery)

Venous drainage:
Superiorly veins drain into pterygoid plexus and inferiorly to facial and internal jugular v

Question 9

Lymphatic drainage of pharynx

Answer 9

Runs w internal jugular v
Lymphatic vessels drain into deep cervical lymph nodes (paratracheal, infrahyoid, retropharyngeal nodes)

(palatine tonsils drain into jugulodigastric nodes)

Question 10

Innervation of pharynx

Answer 10

Motor and sensory mainly by pharyngeal plexus (branches of vagus and glossopharyngeal n)

Motor: all muscles innervated by [X] except stylopharyngeus which is innervated by [IX]

Sensory:
Nasopharynx - [V2]
Oropharynx - [IX]
Laryngopharynx - [X]

Question 11

Mucosal features of pharynx

Answer 11

Nasopharynx:
- Pharyngeal tonsil, opening of Eustachian tube, torus tubularis, salpingopharyngeal fold and pharyngeal recess

Oropharynx:
- Palatopharyngeal arch, palatine tonsil, palatoglossal arch

Laryngopharynx:
- Laryngeal inlet

Question 12

General structure of larynx

Answer 12

Musculoligamentous structure w cartilaginous framework located above lower resp tract
Protects airway and involved in phonation
Continues inferiorly with trachea and superiorly opens into laryngopharynx

Question 13

Larynx components

Answer 13

Cartilages: epiglottis, cricoid, arytenoid, corniculate, cuneiform

Ligaments and fibroelastic membranes: thyrohyoid membrane w its ligaments, hyo-epiglottic lig, cricotracheal lig, cricothyroid membrane w its lig and quadrangular membrane w its lig

Muscles: intrinsic and extrinsic

Question 14

Larynx - cricoid cartilage

Answer 14

From C6 vertebral level
Thickened posteriorly
Made up of arch and lamina
Superiorly has 2 facets for articulation with arytenoid cartilage

Question 15

Larynx - extrinsic membrane

Answer 15

= Thyrohyoid membrane (from lower part of hyoid bone to upper part of thyroid cartilage)
Aperture for internal branch of superior laryngeal n and associated artery
(sup laryngeal originates from sup thyroid a and supplies upper part of larynx and thyroid, inf thyroid a supplies lower part)

Question 16

Larynx - Intrinsic membranes

Answer 16

(deep to thyroid cartilage)
Cricothyroid ligament:
- Where it thickens at upper border = vocal ligament (true vocal cord)

Quadrangular membrane:
- Where lower part is thickened = vestibular ligament (false vocal cord)

Question 17

Vocal cords relation to arytenoid cartilage

Answer 17

Vocal ligament (true) runs from anterior thyroid cartilage to arytenoid cartilage
Vestibular ligament (false) runs from anterior thyroid cartilage to arytenoid cartilage

Vestibular lig (false) more lateral then vocal lig

When arytenoid moves, vocal cords open/close
To breath - abduct/externally rotate arytenoid to open vocal cords
Adduct to talk

Question 18

Piriform recess

Answer 18

Piriform recess lies either side of laryngeal inlet, bound medially by aryepiglottic fold and laterally by thyroid cartilage.
Common place for food and foreign bodies to become trapped (e.g. fish bone)
i.e. to locate food go lateral to aryepiglottic fold

In newborn - majority of larynx is piriform recess (drink milk lying down, recess acts as gutter towards oesophagus)

Question 19

Intrinsic muscle of larynx

Answer 19

Cricothyroid muscle with straight and oblique parts

Question 20

Most important extrinsic muscle of larynx

Answer 20

Posterior crico-arytenoid muscle
ONLY muscle that abducts the ligaments to keep the airways open

Innervated by damage to recurrent laryngeal nerve (from vagus n)

• Damage on 1 side = hoarseness of voice
• Damage on both sides = cannot breathe

Question 21

Blood supply to larynx

Answer 21

Above vocal cords:
Larynx supplied by sup laryngeal a (from sup thyroid a)
Below:
Larynx supplied by inf laryngeal a (from inf thyroid a)

Removing thyroid - must ligate sup thyroid right at gland (if you ligate at origin from ext carotid there will be no supply by sup laryngeal to larynx)

Question 22

Venous drainage of larynx

Answer 22

Inferior and superior thyroid veins

Question 23

Innervation

Answer 23

Sensory:
Above vocal cords - sup laryngeal gives off internal laryngeal n
Below vocal cords - recurrent laryngeal n (from vagus n)

Motor :
All muscles of larynx innervated by vagus [X]