Head and neck

ANATOMY OF NOSEEXTERNAL NOSE

External nose is shaped like a pyramid with its root up and base directed downwards. Consists of osteocartilagenous framework covered by muscle and skin.

ANATOMY OF NOSEEXTERNAL NOSE

Osteocartilagenous framework: Upper 1/3rd - bonyLower 2/3rd – cartilagenousBony frameworkNasal bonesNasal processes of frontal boneFrontal processes of maxilla

ANATOMY OF NOSEEXTERNAL NOSE

Cartilagenous framework Upper lateral cartilages Lower lateral cartilages (alar cartilages) Lesser cartilages (sesamoid cartilages) Septal cartilage Clinical significance: limen nasi (nasal valve) is the narrowest area in the upper airway

ANATOMY OF NOSEEXTERNAL NOSE

Nasal musculature: Procerus Nasalis (transverse and alar part) Levator labi superioris alaque nasi Anterior and posterior dialator naris Depressor septi Nasal skin: skin over nasal bone and upper lateral cartilage is thin and freely mobile while that on alar cartilages is thick and adherent and contains sebaceous glands

ANATOMY OF NOSEEXTERNAL NOSE

Blood supply: facial and ophthalmic arteries and veins Lymphatic drainage: preauricular and submandibular lymph nodes

ANATOMY OF NOSEINTERNAL NOSE

It is divided into right and left nasal cavities by nasal septum. Each nasal cavity consists of Skin lined portion-vestibule (contains sebaceous glands, hair follicles, vibrissae) Mucosa lined portion-nasal cavity proper


ANATOMY OF NOSEINTERNAL NOSE
Nasal cavity proper: bounded by lateral wall, medial wall, roof and a floor. Floor: Formed by Palatine process of maxilla (anterior 3/4th ) Horizontal process of palatine bone (posterior 1/4th )

ANATOMY OF NOSEINTERNAL NOSE

Roof: formed by Anterior sloping part by nasal bones Posterior sloping part by body of sphenoid Middle horizontal part by cribriform plate of ethmoid through which olfactory nerves enter the nasal cavity

ANATOMY OF NOSEINTERNAL NOSE

Septum proper: principal constituents Perpendicular plate of ethmoid postero-superiorly Vomer infero-posteriorly Septal cartilage (quadrilateral cartilage) These articulate with following bones to complete the septum Superiorly-frontal bone, nasal bone, rostrum of sphenoid. Inferiorly anterior nasal spine of maxilla, nasal crest of maxilla and palatine bones

ANATOMY OF NOSEINTERNAL NOSE

Medial wall of nasal cavity (nasal septum)

BLOOD SUPPLY-NASAL SEPTUM

NERVE SUPPLY-NASAL SEPTUM

ANATOMY-LATERAL WALL OF NASAL CAVITY

Lateral wall is marked by three bony projections called turbinates or conchae-superior (part of ethmoid), middle (part of ethmoid), inferior (separate bone). sometimes a fourth turbinate concha suprema may also be present. Bellow and lateral to each turbinate is a corresponding meatus

ANATOMY-LATERAL WALL OF NASAL CAVITY

Inferior meatus- nasolacrimal duct opens in its anterior part. Middle meatus- consists of bulla ethmoidalis, hiatus semilunaris, infundibulum. Frontal, maxillary and anterior ethmoidal sinuses open into middle meatus. Superior meatus- posterior ethmoidal sinuses open into it. Sphenoethmoidal recess- triangular fossa above the superior meatus. Sphenoidal sinus opens into it.

ANATOMY-LATERAL WALL OF NASAL CAVITY

BLOOD SUPPLY-LATERAL WALL OF NASAL CAVITY

NERVE SUPPLY-LATERAL WALL OF NASAL CAVITY

AUTONOMIC NERVE SUPPLY- NASAL CAVITY
Sympathetic supply- superior cervical sympathetic ganglion -> internal carotid plexus -> vidian nerve -> sphenopalatine ganglion. Parasympathetic supply- facial nerve -> greater superficial petrosal nerve -> vidian nerve -> sphenopalatine ganglion. Nasal branches from sphenopalatine ganglion supply the nasal cavity.

SENSORY NERVE SUPPLY-NASAL CAVITY

Trigeminal nerve carries the common sensation via ophthalmic and maxillary divisions. Special sensory (smell) carried via olfactory nerves.

LYMPHATIC DRIANAGE-NASAL CAVITY

Upper deep cervical nodes drain the nasal cavity directly or via the retropharyngeal nodes.

PARANASAL SINUSES-ANATOMY

These are air filled spaces in certain bones of skull and are in direct communication with nasal cavity through their ostia. They are four on each side divided as Anterior group- maxillary, frontal, anterior ethmoidal Posterior group- posterior ethmoid, sphenoid

Maxillary sinus (Antrum of Highmore)

Largest of the paranasal sinuses Pyramidal in shape with base towards lateral wall of nose and apex directed into zygomatic process Capacity- 10-20 ML boundaries- Medial wall- lies between the sinus and nasal cavity Posterior wall- related to pterygopalatine and infratemporal fossae Anterior wall- related to soft tissue of cheek Roof- formed by floor of orbit Floor- formed by alveolar process and palate

FRONTAL SINUS

Situated in between inner and outer table of frontal bone Pyramidal in shape with apex upwards and base is formed by the floor Capacity- 5-10 ML Boundaries Anterior wall-outer table of frontal bone Posterior wall- inner table of frontal bone separates the sinus from cranial cavity Floor- formed by thin bone separating sinus from orbit Medial wall- forms the septum between two frontal sinuses

ETHMOIDAL SINUSES

Thin walled air cavities in the lateral masses of ethmoid bone. Clinically divided into anterior and posterior group Ethmoidal labyrinth has following relations Roof- anterior cranial fossa lateral to cribriform plate Lateral wall- orbit, optic nerve, nasolacrimal duct separated by thin bone called lamina papyracea Inferior- maxillary sinus Posteriorly- sphenoid sinus Medially- superior and middle turbinate

SPHENOID SINUS

There are two sphenoidal sinuses in the sphenoid bone divided unequally by a thin bony septum Relations- Laterally- cavernous sinus containing 3,4,5,6th cranial nerves, internal carotid artery, optic nerve Superiorly- pituitary gland, optic chiasma, olfactory bulb, frontal lobe Inferiorly- nasopharynx and vidian nerve Posteriorly- brainstem, Basilar artery