h&n lecture 17

8/7/2019 H&N lecture 17

http://slidepdf.com/reader/full/hn-lecture-17 1/17

Lecture 17

24 minute

larynx and trachea 2

done by : azam,najwa aiman,nur liyana

slide 2

Today I want to finish talking about thelarynx and talk about the trachea in theneck. Ok, so there are two groups of muscles acting on the larynx. The firstgroup consists of the extrinsic musclesthat elevate or depress the larynx as a whole . Where as the second group

consists of the intrinsic muscles that act on the laryngeal inlet and the vocalcords. So, you can divide the extrinsicmuscles into elevators and depressoraccording to their action on the larynx.So elevators of the larynx are (slides 2)

Slides 3,4

you can see digastric muscle here. Infact this is the posterior belly. Ok, so,again here you can see the posteriorbelly of the digastric muscle , thestylohyoid muscle and then you can see

here the most posterior is call the

8/7/2019 H&N lecture 17


salpingopharyngeus muscle. Then, hereif you remember,this is the soft palate,more anterior is the uvula, and here is

the pharynx. (The doctor then stoplecturing for 5 minutes because thestudents were making noise. Please dohave respect for the dukturah and otherstudents who willingly came to class . drquoted : if you do not care about

yourself,care about others (“,)V )ok so if you remember this the softpalate, this is the larynx.we can see theepiglottis and then this is thepharynx,posterior to the larynx.

So here you can see the muscle fromthe soft palate to the pharynx calledpalatopharyngeus muscle and then thisis the stylopharyngeus muscle. So, all of these pharynx muscle are some of theelevators of the larynx which meansthey are some of the muscles that

elevate the larynx as a whole.

Now if you remember, this the anteriorbelly of the digastric and this is themylohyoid muscles . the two mylohyoidmuscles form the muscular floor of themouth or the oral cavity and the

mylohyoid muscles as well as the

8/7/2019 H&N lecture 17


geniohyoid muscle which is located deepto the mylohyoid muscles also act as theelevators of the larynx. Now the muscles

of the larynx are, you can see thesternohyoid here, sternothyroid, as wellas the omohyoid. If you remember this isthe superior belly and this the inferiorbelly of the omohyoid muscle. Well,there are many intrinsic muscles of the

larynx and whenever you say intrinsic,means that they present within thelarynx. So they insert from parts of cartilages of the larynx and they arisefrom other parts of those cartilages.

Slide 6

8/7/2019 H&N lecture 17


So the intrinsics muscle can be dividedinto two groups. There is the first groupconsist of those muscles that act on thelaryngeal inlet whereas the other group

consist of muscles act on the vocalcords. So the first group consist of twomuscles which are the oblique arytenoidmuscle and the thyro-epiglottic muscle.And the oblique arytenoid muscle arisesfrom the muscular process of the

arytenoid cartilage and insert on theapex of the opposite arytenoid cartilage.The thyro-epiglottic as the nameindicates arises from the medial surfaceof the thyroid cartilage and inserts onlateral margin of the epiglottis and ary-epiglottic fold.

8/7/2019 H&N lecture 17


Thyroepiglottic as the name indicates, itarises from the medial surface of thethyroid cartilage and inserts at the

lateral margin of the epiglottis andaryepiglottic fold. So, as its mentionhere, oblique arytenoids narrowslaryngeal inlet while thyroepiglotticmuscle widens the inlet. (refer table 11-12,slide 6)

Then,the muscles that are controllingthe movement of vocal cords/true vocalcords are cricothyroid, thyroarytenoid,lateral cricoarytenoid, posteriorcricoarytenoid and the transversearytenoid. Now, remember that the

vocalis is consider as heart of thyroarytenoid muscle and its medial toit. Now, cricothyroid arises from side of cricoid cartilage and inserts to the lowerborder and inferior cornu/horn of thyroidcartilage and it tenses the vocal cords.

Thyroarytenoid as well as the vocalisinserts from the inner surface of thyroidcartilage specifically the vocalis muscleimpact arises from the angle betweentwo laminae of the thyroid cartilage andthen this two muscles insert on thearytenoids cartilage and they relaxes

the vocal cords. The lateral

8/7/2019 H&N lecture 17


8/7/2019 H&N lecture 17


So, to view those muscles, here youhave posterior view of ,this is the hyoidbone, this is the epiglottis, this is thyroidcartilage,the lamina of thyroid cartilage,superior horn,inferior horn and thenhere is the lamina of the cricoidcartilage. Here is the aryepiglottic fold.You can see the corniculate cartilagewhich sits on the apex of the arytenoidcartilage and here is the inferior horncartilage anterior to it in thearyepiglottic fold.

8/7/2019 H&N lecture 17


So, here you have muscle that istransversely. this is the transversearytenoids muscle (horizontally) and this

muscle here is the oblique arytenoidmuscle. This is one and this is anotherone. Here, this is the cricoarytenoidmuscle and since you can see itposteriorly, just to remember, so, this isthe posterior cricoarytenoid muscle. A

student ask about blood supply and drsaid will explain it later.

Here, this is just the thyroid cartilage,the lamina, inferior horn, superior horn,and this is the cricoid cartilage, anteriorarch and the posterior lamina. (Doc was

mad at those who were sitting and talking at the back. I think we shouldn’t make the doctor mad and make things(giving lecture) hard for her as shealways try her best (including theexam’s date,material, labs) for us. Just

try to give her a respect during thelecture.For the sake of us too)

So, this cricothyroid cartilage can bedivided into a posterior oblique part orsuperior part, anterior and inferiorvertical part. Then, here is the epiglottis,

here is the cricoid cartilage that has

8/7/2019 H&N lecture 17


been cut.This lamina, the right lamina of the thyroid cartilage has been cut andremoved.And then this is the cricoid

cartilage arch and lamina and this istrachea and this is the cricotrachealligament.so, the cricothyroid muscle hasalready been cut, you can see the lateralcricoarytenoid muscle on its lateral view,and then between the arytenoid

cartilage and thyroid cartilage, you cansee the thyroarytenoid muscle. Finallyyou can see the thyroepiglottic musclebetween the thyroid cartilage and theepiglottis.

8/7/2019 H&N lecture 17


SUPERIOR VIEW

If you look at the larynx superiorly,theintrinsic muscle that can be seen arefirst, this is thyroid cartilage and here is

the arytenoid cartilage and so this is thethyroarytenoid muscle. Medial to it is thevocalis muscle.Now, again this is thelateral cricoarytenoid muscle and this isthe posterior one. Here, you can see thetransverse and then the oblique

arytenoid muscle. Okay, so I’ve alreadytold you about the sensory innervations

8/7/2019 H&N lecture 17


of the larynx in the last lecture buthere,you have,this is the superiorlaryngeal nerve which is the branch of

the vagus. So,here you have commoncarotid artery, the vagus nerve andthere is internal jugular vein that hasbeen removed. All of these are withinthe carotid sheath which has beenremoved.

Slide 10,12 next page…

8/7/2019 H&N lecture 17


Now, the branch of vagus nerve issuperior laryngeal nerve which divide to

internal branch that pass together withsuperior laryngeal artery. superiorlaryngeal artery is a branch of superiorthyroid artery which is branch of external carotid artery.

Now remember that the internal branch

of superior laryngeal nerve is sensory to

8/7/2019 H&N lecture 17


the larynx to down as far as vocal foldsor the true vocal cords. Then, here youhave the Recurrent laryngeal nerve. This

is the vagus. Recurrent laryngeal nerveis for sensory innervations to that part of the larynx below the vocal cords.

Now, the Recurrent laryngeal nerve alsoprovide nerve supply to the muscles,intrinsic muscle of the larynx. All theintrinsic muscle of the larynx exceptcricothyroid muscle which receives itsmotor innervations from externalbranch of the superior laryngeal nerve.

Slide 11,12

Now, regarding to blood supply, this isthe right side, this is the left side. So,this should be the brachiocephalic trunk,this is arch of aorta. The brachiocephalictrunk divides into the common carotidartery and subclavian artery. Now thecommon carotid artery divides into theinternal carotid artery and the externalcarotid artery. The external carotidartery gives off the superior thyroidartery which gives off the superiorlaryngeal artery. Now, the superiorlaryngeal artery provides blood supply

to the upper half of the larynx. While the

8/7/2019 H&N lecture 17


lower half of the larynx is supplied byinferior laryngeal artery which is branchof inferior thyroid artery. So here is the

inferior thyroid artery which is branch of thyrocervical trunk which is branch of subclavian artery.

Slide 13,14

THE TRACHEA

The trachea. You know that the larynxcontinues as trachea. So, here is the firsttracheal ring and of course the trachealbegins at level of CV6. So now, if youremember from histology, the trachea is

lined by pseudostratified columnarepithelium and its wall consist of Ushaped hyaline cartilages that isconnected superiorly by smooth musclecalled trachealis. The trachea divides(bifurcate) at the level of sternal angle

into two main bronchi (right and left).Now, this cartilaginous ridge that endsanterior posteriorly at lower end of trachea (at its birfurcation) is called thecarina.

So, this is the thyroid cartilage.it consist

of an isthmus and two lateral lobes.

8/7/2019 H&N lecture 17


Now remember that the thyroid cartilageespecially the isthmus of it, covers theanterior part of the trachea. we also

have the inferior thyroid vein located infront of the trachea. Now, of coursethere are sternohyoid and sternothyroidmuscles which are overlapping thetrachea that has been removed.Laterally, you can see this lateral lobe of

the thyroid gland and the carotid sheathand its contents which are the cartilageitself, vagus nerve and internal jugularvein. Posteriorly, you will see theesophagus (It is the continuation of thepharynx) and recurrent laryngeal nerve.

Now remember that the lymph drainsfrom the pharynx into the deep cervicalnode and remember that the tracheareceive its sensory innervations fromrecurrent laryngeal nerve which isbranch of the vagus nerve, and the

vagus nerve itself.

8/7/2019 H&N lecture 17


The trachea receives its blood supplythe inferior thyroid artery and from thebronchial artery. This here one and theother one. Those are the branches of thearch of aorta. Finally, the lymph drainsfrom the trachea into paratracheal

lymph nodes (para means they are tothe sides of trachea) and they also havepretracheal (pre is anterior or before)lymph nodes which located anterior. Sothe pretracheal lymph nodes is at theanterior surface of trachea and finallyinto the deep cervical lymph nodes.

8/7/2019 H&N lecture 17


“ONE OF THE HOW TO RESPECT

OURSELVES IS TO RESPECT OTHERSWHETHER KIDS, FRIENDS, OLDPEOPLE, ESPECIALLY OUR

TEACHERS, IF YOU ARE BEING RUDETO THEM MEANING THAT YOU ARE

RUDE TO YOURSELVES.”

RESPECT YOURSELF,RESPECTOTHERS.YOSH!

h&n lecture 17

Documents