ENT Anatomy and PhysiologyENT Anatomy and Physiology

Dr. ZAID AL-DAHWIConsultant ENT

Head of ENT department

KING SAUD MEDICAL CITY

ENT Undergraduate Lecture

Ear Anatomy Ear Anatomy External EarExternal Ear

• Auricle (Pinna)– Collects sound– Sound

localization

Ear Anatomy Ear Anatomy External EarExternal Ear

• External audiotary meatus– Approximately 24mm in

length, “S” shaped– Lateral/Outer 1/3

• in cartilages • wax (cerumen) • hair

– Medial 2/3• bone• wax free

– Skin migration

Increases sound pressure at the tympanic membrane by as much as 5-6 dB (due to acoustic resonance)

Ear Wax (Cerumen)Ear Wax (Cerumen)

1.Keeps skin soft

2. Keeps bugs out

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Mastoid ProcessMastoid Process

• Bony ridge behind the auricle

• Provides support to the external ear and posterior wall of the middle ear cavity

Middle Ear Anatomy Middle Ear Anatomy Boundaries of Middle Boundaries of Middle

EarEar• Middle ear is Air containing space

in temporal bone.

Middle Ear Anatomy Middle Ear Anatomy OssiclesOssicles

• Three ossicles • Mallus, • incus • stapes

• Ossicles are smallest bones in the body

• Act as a lever system• transfer sound from air to

inner ear fluids

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Stapedius MuscleStapedius Muscle

• Connects the stapes to the middle ear wall• Contracts in response to loud sounds; known

as the Acoustic Reflex

Middle Ear Anatomy Middle Ear Anatomy Tympanic membraneTympanic membrane

• Thin membrane• Forms boundary between outer and middle ear• Vibrates in response to sound• Changes acoustical energy into mechanical

energy

Middle Ear Anatomy Middle Ear Anatomy Eustachian tube Eustachian tube

• Equalises pressure between middle ear and atmosphere

Middle Ear Anatomy Middle Ear Anatomy medial wallmedial wall

Oval window Footplate of the

stapes

Round window

Promontory

Middle Ear Anatomy Middle Ear Anatomy The posterior wallThe posterior wall

Mastoid wall

Tympanic aditus

Pyramidal

eminenceChorda tympani

nerve

Ear Anatomy Ear Anatomy Inner EarInner Ear

• Cochlea

• Semicircular canal – Angular acceleration

• Vestibule – Linear acceleration

• Sound transmission through middle ear• Oval Window –

– located at the footplate of the stapes; when the footplate vibrates, the cochlear fluid is set into motion

• Round Window – – functions as the pressure relief port for the fluid set into motion

initially by the movement of the stapes in the oval window

• Cochlea : organ of corti– Snail-shaped organ with a series of fluid-filled tunnels;

converts mechanical energy into electrical energy

Inner Ear Inner Ear CochleaCochlea

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Organ of CortiOrgan of Corti

• The end organ of hearing; contains stereocilia and hair cells.

Hair Cells Frequency-

specificHigh pitch sounds

(base of cochlea)Low pitch sounds

(apex of cochlea)

Inner Ear Inner Ear Vestibular FunctionVestibular Function

• Macula in saccule and utricle – linear acceleration

• Crista in semi-circular canal – angular acceleration

RhinologyRhinology

• Anatomy

• Physiology

Rhinology Rhinology AnatomyAnatomy

• External

Rhinology Rhinology AnatomyAnatomy

• LATERAL WALL OF NASAL CAVITY

It has 3 curved long projections called nasal conchae:

1) Superior turbinate.

2) Middle turbinate.

3) Inferior turbinate.

* The space below each of these conchae is called nasal meatus.

Rhinology Rhinology Nasal septumNasal septum

• Above:– perpendicular plate of

the ethmoid.• Below and in front:

– septal cartilage.• Below and behind:

– vomer.

– Little’s area– Epistaxis

Rhinology Rhinology Roof Roof

• narrow

Formed by :

1.cribriform plate of the ethmoid bone

2.nasal and frontal bones, and posteriorly sphenoid Bone.

Rhinology Rhinology Paranasal SinusesParanasal Sinuses

– Frontal

– Maxillary

– Ethmoid

– Sphenoid

Laryngology Laryngology (Mouth - Pharynx-Larynx-)(Mouth - Pharynx-Larynx-)

Laryngology Laryngology ORAL CAVITYORAL CAVITY

• 1. Lips. • 2. Buccal or cheek

mucosa. • 3. Gums (gingivae). • 4. Hard palate. • 5. Oral tongue. Only

anterior two-thirds

Laryngology Laryngology PHARYNXPHARYNX

• 1. NasophcHynx– extends from the base of skull to

the soft palate

• 2. Oropharynx– extends from the base of skull to

the soft palate includes (Base of tongue, Lingual and Palatinc tonsils, Valleculae)

• 3. Hypopharynx or Laryngopharynx

– extends from hyoid bone to lower border of cricoid cartilage

– continuous with oesophagus.

– opposite the 3rd, 4th, 5th, 6th cervical vertebrae.

– pyriform sinus, post-cricoid region and the posterior pharyngeal wall.

• Structure of Pharyngeal Wall– 1. Mucous

membrane– 2. Pharyngeal

aponeurosis (pharyngobasilar fascia)

– 3. Muscular coat– 4. Buccopharyngeal

fascia

Laryngology Laryngology PHARYNXPHARYNX

• Waldeyer's Ring– Masses of Scattered

lymphoid tissue in the pharynx

• l. Nasopharyngeal tonsil or the adenoids

• 2. Palatine tonsils or simply the tonsils

• 3. Lingual tonsil

• 4. Tubal tonsils (in fossa of Rosenmuller)

• 5. Lateral pharyngeal bands

• 6. Nodules (in posterior pharyngeal wall).

Laryngology Laryngology PHARYNXPHARYNX

palatine (faucial) tonsilspalatine (faucial) tonsils

• Blood Supply of tonsils– l. Tonsillar branch of fac

ial artery. – 2. Ascending pharyngeal

artery from external carotid.

– 3. Ascending palatine, a branch of facial artery.

– 4. Dorsal linguae, branches of lingual artery.

– 5. Descending palatine branch of maxillary artery.

palatine (faucial) tonsilspalatine (faucial) tonsils

• Relations of tonsil

palatine (faucial) tonsilspalatine (faucial) tonsils

• Crypts of tonsil

Laryngology Laryngology LARYNX AnatomyLARYNX Anatomy

Laryngology Laryngology Neck AnatomyNeck Anatomy

Laryngeal CartilagesLaryngeal Cartilages

• Paired

– Arytenoid cartilage– Corniculate

cartilage– Cuneiform

cartilage

• Unpaired:

– Thyroid cartilage– Cricoid cartilage– Epiglottis

Thyroid CartilageThyroid Cartilage

• Angulation more acute in males

• Its function – Shield larynx from injury and – Provide an attachment to vocal cords

Cricoid CartilageCricoid Cartilage

• Signet ring shaped• Stronger than thyroid

cartilage.

• Support to arytenoid

• Only cartilagenous part forms continuous 360 degree ring

EpiglottisEpiglottis

• Thin leaf shaped fibro-cartilage, situated in midline

• Upper free projects up behind base of tongue

• Epiglottic cartilage contains many pits filled with mucous glands

ArytenoidsArytenoids• Paired cartilages, pyramidal

in shape

• Base articulated with cricoid cartilage

• Anterior angle elongated into vocal process which receives insertion of vocal ligament

GlottisGlottis• Consists of

– true vocal cords, – anterior commissure and – posterior commissure

• Anterior 2/3 is membranous

• Posterior 1/3 of cords are called posterior commissure

Intrinsic musclesIntrinsic muscles

Cricothyroid MuscleCricothyroid Muscle

Adductors of the Vocal FoldsAdductors of the Vocal Folds

Abductor of LarynxAbductor of Larynx

Nerve Supply: Derived from the Nerve Supply: Derived from the VagusVagus

• Superior Laryngeal Nerve – Internal -It provides

sensation of the glottis and supraglottis,

– External -It supplies motor function to the cricothyroid muscle which tenses the vocal cords

• Recurrent Laryngeal Nerve – sensation to the subglottic – motor function to the

intrinsic muscles of the larynx.

• Recurrent Recurrent Laryngeal NerveLaryngeal Nerve

– It branches from the vagus in mediastinum and turns back up into the neck.

– On the right, it travels inferior to the subclavian and loops up

– on the left it travel inferior to the aorta and loops up.

THE ENDTHE END

Questions?