Anatomy of the larynx

Prepared by

Dr. Muaid I. AzizOtolaryngologist–head & neck

surgeonM.B.Ch.B F.I.C.M.S

• The Larynx is the organ of voice production• placed at the upper part of the air passage.• It is situated between the trachea and base of the

tongues, lies opposite the 3rd- 6th cervical vertebrae.

AnatomyAnatomy

• The framework of the larynx consist of :-

Hyoid boneCartilaginous skeletonmusclesLigaments & membranesneurology

U-shaped bone w give attachment for many of the ext.

muscles of the larynx & suspend it in the neck

Hyoid boneHyoid bone

• 9 diff. seg.of cart.

3 unpaired (epiglottis, thyroid , cricoid)

3 Paired (arytenoid , corniculate ,cuneiform)

Cartilaginous skeletonCartilaginous skeleton

• composed of elastic fibrocartilage Shaped like a leaf , project upwards behind the tongue & hyoid body.

• connected to the hyoid & thyroid cart. by hyoepiglottic & thyroepiglottic lig. Respectively.

EpiglottisEpiglottis

Attached to the tongue base via median& lateral Glossoepiglottic folds w form depression called vallecula.

Thyroid cartilageThyroid cartilage

• 2 quadrilateral-shaped lamina fused in the midline in 90-120 degree

• level of v.c in the males is halfway bet. the notch & inf. edge of thy. c

• Wile in the females is 1/3 the distance.

Oblique line

• the only complete ring. Signet ring w narrow

arch ant. & a broad lamina post.

At C3-4 in child At C6-7 in adult

Cricoid cartilageCricoid cartilage

o Irregular , 3-sided pyramids w forward projection (vocal

process ) attached to the vocal folds

Lateral projection (musc.process) (PCA ,LCA) m.

Apical process attached to the aryepiglottic fold

Vocal process cricoid cart

Muscular process

Arytenoid cart

Arytenoid cartilageArytenoid cartilage

2 synov. J.: cricothyroid & cricoaryt.Cricothyroid j allowing changes in the v.c

lengh.Cricoaryt. J helps to manipulate the v.c in

needed direction.

• Abduction– Posterior cricoarytenoid

• Adduction– Lateral cricoarytenoid– Transverse arytenoid– Oblique arytenoid

• Tension– Thyroarytenoid– Cricothyroid

Intrinsic Muscles of the Larynx

Intrinsic Muscles of the Larynx

Anatomy:laryngeal motionVocal cord abduction of

Adduction of vocal cord

Tension of vocal ligament

• Infrahyoid strap m.: Depress the hyoid & larynx

1. thyrohyoid2. Sternohyoid 3. Sternothyroid • Suprahyoid strap m: Elevate the hyoid & larynx1. Stylohyoid2. Diagastric 3. Mylohyoid 4. Genohyoid5. Stylopharyngeus6. Palatopharyngeus7. salpngopharyngeus

Extrinsic Muscles of the Larynx

Extrinsic Muscles of the Larynx

• The ext. lig. Connect the laryngeal cart. to the hyoid above & trachea below

Ligaments & membranes of the larynx Ligaments & membranes of the larynx

• The int. lig. Connect the laryngeal cart. together. Elastic memb. W supports endolarynx has an

upper part ( quadrangular memb. W spans from aryt. to epig.)

the free inf. edge is called ventricular lig.= false v.c.

the free sup. edge ultimately forms(AE)fold

Lower part (conus elasticus) w spans from sup. border of cricoid to the lower ant. border of thy.cart., thus forming crico - thyroid memb.

Vocal lig. , the sup. edge of the conus elasticus,is the fibrous core of v.c w extend from ant. midline of thy.c (broyles lig.) to v. process of aryt. Cart.

Spaces within the larynxPre-epiglottic space:Ant: th.c & thyro-hyoid

memb.post: epig.& thyr-epig. Lig.Sup: hyo-epig.lig .&

vallecular mucosa

Pre-epiglottic space

Paraglottic space is formed by the : thyroid lamina lat. conus elasticus &quadrangular memb.

Med. pyriform fossa post.

Internal branch of s.l.n

Nerves of the LarynxNerves of the Larynx

Vocal fold histologyVocal fold histologyVocal fold histologyVocal fold histology