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Pictures are included in the last three pages , so refer to them
while studying.
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T Tongue :p
1] Innervation of The Tongue:
tongue innervation is very important, carried out mostly by cranial nerves ( by four
cranial nerves).
Sensory
It is divided into general sensation ( thermal, pressure, pain,
touch "touch receptors are located in the post central gyrus
of the brain and carried by PNS") and special sensation( in
medicine we have 4 special senses not 5). Different
embryological origins resulted in different innervations
anteriorly and posteriorly.
1) General : Anterior 2/3 of the tongue  the lingual nerve of
mandibular branch of the trigeminal (V) [ V is the largest
cranial nerve] while the Posterior 1/3  glossopharyngeal
(IX).
2) Special (taste) : Anterior 2/3 facial nerve (VII) while the
posterior 1/3  Glossopharyngeal ( IX)
Motor
All muscles of
the tongue are
innervated by
hypoglossal
nerve (XII)
except
palatoglossus.
2] Arterial Blood Supply to The Tongue
Tongue is mainly supplied by the lingual artery (which is a branch of external carotid
artery) deep to the hyoglossus muscle. When the lingual reaches the tongue, it gives
3 branches : 1) dorsal lingual artery to the posterior 1/3.
2) deep lingual artery to the anterior 2/3 (it appears through the mucus membrane).
3) sublingual branch  this branch is the main blood supply of thestructures of the
mouth floor such as sublingual salivary gland “mainly”.
In addition, Tonsillar artery (branch of facial artery) will help in supplying the
posterior 1/3 of the tongue where the palatine tonsil is present. Ascending
pharyngeal artery(branch of the external carotid artery) ascends on the pharyngeal
wall supplying the pharyngeal part of the tongue in the oropharynx, but mainly it
supplies the pharynx.
P.s : Tonsillar and ascending pharyngeal arteries are helpers while lingual artery is the
main supplier of the tongue.
3] Lymph drainage
it is important because it determines the problems in the tongue –tumors mainlyand has its own characteristic features.
◘ At the Tip of the tongue drains into sub-mental L.N in the sub-mental
triangle.
If these L.N are enlarged and rubbery (ma bt7ess fehum), it indicates a problem
in the tongue tip.
◘ Lateral anterior 2/3  each one is epsi-lateral , drains into submandibular L.N
below the mandible. If these L.N are affected , it indicates a problem in the lateral
anterior 2/3.
◘ medial anterior 2/3  inferior deep cervical L.N named as jugulo-omohyoid
L.N (jugulo: neck , omohyoid: at the intermediate tendon of omohyoid muscle) SO
enlargement of these L.N indicates problems in the medial anterior 2/3.
◘ posterior 1/3  here is the lingual tonsil which drains into the superior deep
cervical L.N (at the mandibular neck) called the jugulo-digastric L.N behind the
mandibular angle (jugulo: neck, digastric: at the intermediate tendon of the
digastric muscle "two fleshy parts").
Physicians use tongue suppressor and palpate juglo-digastric L.N "at the neck of
the mandible" , if enlarged and tender  inflammation either in the lingual tonsil
(posterior 1/3 of the tongue) or more commonly in the palatine tonsil
“tonsillitis”, BUT if they are enlarged rubbery and non-tender, it indicates a tumor
or cancer.
4] Genioglossus& Airway Patency:
genioglossus is the largest muscle of the tongue. It originates from genial
tubercle “mental spine” going all the way to the tongue. it is under constant
state of contraction (non-relaxed) to keep the tongue forward preventing it
from collapsing backward (keeping it in its position), so if it is relaxed, the
tongue will relapse backward closing the upper airways (oropharynx) leading
to suffocation. While hyper-contraction of genioglossus muscle will protrude
the tongue out of the mouth ( like this “:p”). This is an important issue under
general anesthesia in the operation room, fibers will relax so the tongue will
relapse backward leading to suffocation ( fa by3’yeb), that’s why they put
plastic tube through the nose or the oral cavity (intubation) when applying
general anesthesia, so there is no matter if the tongue relax after relaxation of
genioglossus because the tube will keep the upper pathway patent. In CPR, you
have also to maintain the airways (checking the state of the tongue –not to be
collapsed). When the patient has coma, elevate the neck and extend the head in
order to make sure there is a small passage of air even though the tongue is
collapsed backward.
5] Clinical: Deviation of The Tongue:
we have two genioglossus muscles, they are innervated by hypoglossal nerve.
So in order to check the function of this nerve, we will ask the patient to
protrude his tongue, knowing that normally the right muscle will pull the
tongue to the left side and the left one pulls it to the right side so the resultant
position is in the middle. If his tongue is deviated to the left the left muscle is
affected but if it deviated to the right side  the right muscle is affected. So the
general rule is : ( the tongue deviates to the damaged or paralyzed side resulted
from nerve damage).
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Salivary Glands
Salivary glands are accessory structures in the head and neck region, they are
3 glands :
1. parotid gland ( the largest one but not the most functional, 30% of saliva).
2. submandibular (60% of saliva)
3. sublingual (5% of saliva).
We have hundreds of minors of individual unicellularcells distributed in the
oral cavity secreting saliva. (5%)
So lets see the anatomical details of these glands:
♥Parotid Gland :
1. the largest one
2. triangular wedge shaped with the base superiorly below the zygomatic arch
and the apex inferiorly behind the angle of the mandible.
3. covered by a very strong dense connective tissue sheath “ the parotid
capsule” derived from investing layer of deep cervical fascia.
4. divided by the facial nerve into superficial and deep parts.
5. looking superiorly in a cross section : you will see the oropharynx and the
skin outside, the parotid gland is placed between the mandible and the
mastoid process. See the picture in the last page.
6. special features: it has vital structures (artery, vein and nerves) so any
cervical procedure in this gland will not be as easy as other glands  we open
the mandible in tumors of submandibular gland and remove it and the same to
sublingual gland tumor, while parotid gland tumor is a severe problem
because of the vital structures inside, when you do parotid cervical removal ,
you will go first with blunt dissection to search for these structures and isolate
them in order to remove the parotid gland piece by piece not completely one
time.
So what are these vital structures ? (arranged from outside to inside)
1) Superficial : facial nerve that terminate into 5 branches within the parotid
gland to supply muscles of facial expression ( temporal branch supplies frontalis
+ orbicularis oculi / Zygomatic branch supplies zygomatic muscles and
orbicularis oculi/ buccal branch supplies buccinator / Mandibular branch
supplies muscles of the lower lip/ Cervical branch supplies platysma+
stylohyoid), so when you do a surgery, you have to take care of these branches
because any cut of anyone will paralyze the muscles it supplies.
Mumps virus causes inflammation and pain in the parotid gland edema
inserting tension on the surrounding capsule  pressurize the facial nerve
resulting in numbness and facial palsy at that side ( eye drop , salivation because
of dropped mouth angle).
2) Middle : Retro-mandibular vein , very large vein behind the mandible within
the parotid, it is formed by union of two veins : superficial temporal vein that
drains the temple “the lateral area of the scalp” and the Maxillary vein that drains
the anterior area of the face and the maxilla. So if you remove the parotid gland
you will end up with sever bleeding.
3) Deep : external carotid artery with its two terminations leaving the gland:
superficial temporal artery and deeply, the maxillary artery.
as a general rule: arteries are always deep to veins giving more protection to the
arteries. WHY? Because arteries have higher blood pressure , if a problem occurs,
it will lead to prolonged bleeding with no control , so they are protected more.
4) parotid L.N : distributed within and on the gland draining into the deep
cervical L.N.
All in all , the presence of these vital structures inside the parotid gland makes
surgical procedures more complicated than other glands.
7. Parotid Duct (Stensen's duct)
it is discovered by the Denmark scientist called nikolas steno. It arises from the
anterior part of the parotid gland passing over one of the strongest muscles, the
Masseter ”masticatory M.” . At the anterior border of the masseter, the duct will
turn medially and penetrate or pierce another muscle which is muscle of the
cheek , Buccinator “facial expression M.” and open in the oral cavity opposite to
nd
the upper 2 molar in the vestibule.
8. parotid gland secrets only serous saliva.
Saliva types : serous (aqueous or watery) and mucus (viscous)
♥ Submandibular gland :
1. it is a mixed gland i.e it secretes both mucous (10%) and serous (90%).
Serous saliva contains digestive enzymes, mainly amylaze that breakdown
carbohydrates, and some lipases that breakdown lipids. So serous has digestive
function.
Mucous contains lysozymes “that destroy the cell membranes and organelles”
and munoglobulin Abs. so Mucous has protective function.
2. this gland rests on the posterior border of mylohyoid muscle. This muscle is
flat originating from both sides of the mandible all the way to the middle
emerging with the hyoid bone there. “Mylo: molar”. It is the marker for the floor
of the mouth SO anything below Mylohyoid is in the neck and anything above it is
in the oral cavity.
Submandibular gland has two parts :
* one above mylohyoid muscle, smaller , called deep part in the oral cavity.
* and the other is below it which is larger , called superficial part of
submandibular gland and it is easily palpated in the neck below the mandible.
3. Submandibular duct (Wharton’s referring to thomaswharton, an English
physician): it arises from the deep part of the gland passing anteriorly and opens
beside the frenulum (sublingual papilla) below the tongue “in the floor of the
mouth”. If you raise your tongue, you will see its orifices. This duct has the same
length of parotid duct ~ 5cm.
Most of the saliva is below your tongue (moist area) and that makes sense
because 60% of saliva is secreted from the submandibular gland and 5% is
secreted from the sublingual gland which are located there.
♥Sublingual gland:
1. it is a mixed gland that secrets serous and mucous “mainly mucous”, located
beneath the mucous membrane of the floor of the mouth, so if you injure this
area with a sharp tool, you can easily open into the sublingual gland.
2. it opens into the floor of the mouth (sublingual fold) through several ducts
varying in number among individuals (8-20 small ducts), called ducts of
Rivinus, three or four of these ducts unite to form large one called duct of
partholien.
Pharynx :
A funnel shaped fibromuscular tube (striated muscle+ fibrous tissue this
muscle holds a fibrous raphe called pharyngeal raphe) extends from the base of
skull (occiput)& continues below with esophagus at the level of C6. It is divided
into three parts :
1. oropharynx (behind the mouth)
2. nasopharynx (behind the nose)
3. laryngeopharynx behind the larynx.
There are three constrictor muscles that make the funnel shape of the pharynx.
All constrictors attach to the pharyngeal raphe behind. They overlap each other
from down "inferior" to up"superior". WHY ? To keep the food within the
muscles during contraction.
1) superior constrictor. 2) middle constrictor that overlaps with the superior
one. 3) inferior constrictor that overlaps with the middle one. They perform a
successive contraction ( the superior one contracts then the middle then the
inferior down to the esophagus) for Milliseconds  producing the action of
Swallowing.
Pharynx is made of 6 muscles ; 3 small vertical assisting in laryngeal elevation ,
and 3 circular constrictors “ posterior superior circular direction” not
horizontal, pushing down during contraction. With one exception: the inferior
part of the inferior constrictor muscle has different direction.
The inferior constrictor muscle attaches anteriorly with two cartilages : thyroid
and cricoid cartilage below, the direction of fiber changes from posterior
superior (till the end of the part attached to thyroid) to horizontal (the part
attached to the cricoid) and lastly inferiorly .
The inferior constrictor muscle is the largest one, it has two parts,
thyropharengeal part above and cricopharengeal part below according to their
attachment with thyroid and cricoid cartilage respectively . The cricopharyngeal
part has a different function rather than swallowing which is prevention of
regurgitation ( back flow of the food)  acting as a sphincter closing the
esophagus “ upper esophageal sphincter “, SOcricopharyngeal muscle has a
sphincteric function because of their horizontal direction of fibers.
There is a triangular gap between the thyropharyngeal (posterior superior
direction) and cricopharyngeal (horizontal direction) called the Killian’s
Dehiscence (referring to a German anatomic surgeon ghostabkillian , the first
one to use bronchoscopy). This gap has only mucous membrane  it is a weak
area resulted from changing fibers directions . The mucous membrane may
protrude (pharyngeal pouch) because of the absence of muscle fibers in this
trianglei.e no support.
Pharyngoesophageal diverticulum “pouch” is also called zinker diverticulum
(referring to FredriekZinker):
◘ Manifestation of this pouch :
-It mainly affects older people, WHY? Because of weak musculature.
- usually asymptomatic , however, if it starts enlarging , this will lead to
dysphagia (swallowing difficulty), regurgitation and cough.
◘ Diagnosis : simple barium meal to show the pharyngeal pouch.
◘ Treatment :
Small, asymptomatic  no treatment.
Large, symptomatic  endoscopic stapling (closing it by clips)
Vertical muscles that help in elevating the larynx :
1. Stylopharyngeus m.:
originates from the styloid process to the posterior Border of the thyroid
cartilage, it passes through the gap between two muscles; superior and middle
constrictors to enter inside the pharynx with glossopharyngeal nerve.
All pharyngeal muscles are innervated by vagus nerve via pharyngeal plexus
except stylopharyngeus which is innervated by glossopharyngeal N.
2. Palatopharyngeus m.:
originates from the soft palate (Palatal aponerousis) to the pharynx (posterior
border of the thyroid cartilage) .
There are two important muscles coming from the soft palate, palatoglossus that
forms the border between the oral cavity and the pharynx , AND palatopharyngus.
Tonsillar bed (for palatine tonsil) is present in the space between these two
muscles. Mucous membrane will make a fold on palatoglossus muscle making
palatoglossal fold then the mucous membrane will go down to the tonsillar bed
and fold on the palatopharyngeal muscle making the palatopharyngeal fold (the
markers for palatine tonsil). Palatine tonsil lies between these two folds , this
tonsil enlarges if inflammed “tonsillitis”.
P.s : if you cut the fold you will find the corresponding muscle that has the same
name.
3. Salpingopharyngeus m.( the trumpet):
small tiny single bundle of skeletal fibers going down from the Auditory tube or
the eustachian tube (medial end) and blends with palatopharyngeus. It has no
clinical or functional importance.
There is a smaller muscle for facial expression which is called
levatorlabisuperioris dilator alaquinasi ( small bundle of fibers from the nose to
the upper lip)  the longest name for a muscle in humans.
Your colleague : AlaaRasmiBaniBakr
Innervation of The Tongue
Arterial Blood Supply to The Tongue
Lymph Drainage
Genioglossus& Airway Patency
Parotid Gland
Clinical: Deviation of The Tongue
Walls of Pharynx
The Dr skipped this slide
the 2nd presentation slide #3
Structures Within Parotid Gland
Submandibular and sublingual
Salivary Glands
Pharynx
Structures Within Parotid Gland
Muscles of Pharynx