THE NOSE AND PARANASAL SINUSES
Dr. Ali A. Muttalib Mohammed Assistant Professor/ Consultant Otolaryngologist Head of ENT Dept, College of Medicine, University of Mosul In charge, Mosul Centre, Iraqi Board of OtolaryngologyUndergraduate, The Nose, 2013/2014
THE NOSE AND PARANASAL SINUSES
The external nose is supported by bone and cartilage. The bony part is formed mainly by the nasal bones and by the frontal process of the maxillary bone. The cartilaginous portion is formed by several cartilages which support and give shape to the lower part of the nose.
Is the midline partition of the nasal cavity. It is formed by:Anteriorly quadrilateral cartilage.Posterosuperiorly perpendicular plate of ethmoid.Posteroinferiorly vomer.
The nasal septum
The nasal septumIs the entrance of the nasal cavity lined by hair-bearing squamous epithelium which ends at the mucocutaneous junction at which the nasal cavity begins. This hair is called the vibrissae.
Are two irregular cavities extending from the vestibule (anterior nares) to the nasopharynx (posterior nares or choanae) . The nasal cavity has its axis at right angle to the face. The lining of the cavity is mainly pseudostratified ciliated columnar epithelium (respiratory type).
Floor: maxilla and palatine bones. Roof: Nasal bones, cribriform plate of ethmoid and sphenoid bone. Medially: nasal septum. Laterally: there is a system of ridges (turbinates), each of which overhangs a groove (meatus). The turbinate is formed from erectile tissue covered by a mucous membrane.
The turbinates are three in number. The superior and middle turbinates are part of the ethmoid bone, while the inferior turbinate is a separate bone.
The lateral nasal wall
Inferior meatus: nasolacrimal duct Middle meatus: Maxillary sinus Frontal sinus Anterior ethmoid Superior meatus: posterior ethmoid Sphenoethmoidal recess: sphenoid sinusSagital section
1. Sphenopalatine artery (maxillary). 2. Greater palatine artery (maxillary). 3. Superior labial artery (facial).(External carotid artery)4. Anterior ethmoidal artery (ophthalmic artery)5. Posterior ethmoidal artery (ophthalmic artery) (Internal carotid artery) These vessels anatomse forming Keissel-Bach’s plexus in Little’s area.
Facial + ophthalmic vein cavernous sinus.Submandibular, retropharyngeal and deep cervical chain.
1. Sensory: ophthalmic (anterior ethmoid) and maxillary (sphenopalatine) nerve. 2. Secretory: Vidian nerve (nerve of pterygoid canal) which is formed by the junction of the greater petrosal nerve, a branch of the facial nerve (parasympathetic) and the deep petrosal nerve (sympathetic) derived from the sympathetic plexus on the internal carotid artery .
- Greater petrosal nerve (parasymp.) Dilates blood vessels + enhance gland secretion.- Deep petrosal nerve (symp.) constricts blood vessels.3. Olfactory: The olfactory epithelium which is yellowish in colour occupies the cribriform plate, the upper one third of lateral nasal wall (up to superior turbinate) and corresponding part of nasal septum. The oflactory nerves (18-20) on each side pass through the cribriform plate to synapse in the oflactroy bulb. . Injury to these nerves can open CSF space leading to CSF rhinorrhea or meningitis.
Are air filled cavities located inside the facial bones, lined by an evagination of the mucous membrane of the nose and have communication with the nasal cavity. Ant. Group Frontal. Maxillary (Middle meatus) Anterior ethmoidal Post Group Posterior ethmoidal (Superior Meatus) Sphenoid (Sphenoethmoidal recess)
This sinus is pyramidal in shape with base towards lateral wall of nose and apex directed laterally into the zygoma. Its roof is the floor of the orbit and its floor lies over the 1st premolar – 3rd molar teeth. The ostium of the sinus is sited high in the medial wall (1 cm) and hence drainage is dependent on ciliary action and not gravity.
The sinus is not present at birth but appear at the age of 5 years. The sinus is frontal in location ethmoidal in origin. The frontal sinuses are rarely symmetrical and they are separated by a thin bone. The roof of the orbit forms the floor of the frontal sinus.
The ethmoid bone is made up of five parts; the perpendicular plate, the horizontal cribriform plate, the crista galli and two lateral labyrinths of cells suspended by the horizontal plate.
The ethmoidal sinuses are multiple air cells (7-15) in number and divided into anterior and posterior groups which drain respectively into middle and superior meatus. They are separated from the orbit by a thin plate of bone known as lamina papyracea.
This sinus occupies the body of the sphenoid bone and drains into the sphenoethmoidal recess. The pituitary gland is located on its roof whereas the lateral wall is in contact with the cavernous sinus, internal carotid artery, and II, III, IV, V and VI cranial nerves. The Vidian nerve passes below this sinus.
1. Olfaction. 2. Respiration a. Provide an airway for respiration. b. Filtration of air. c. Humidification and warming of the inspired air. 3.Vocal resonance. 4. Collect moisture from the expired air to prevent excessive loss. 5. The mucus is transported by the action of the cilia and contains antibodies which act as a defense mechanism
Particles Dissolved in mucous Carried to olfactory mucosa [Nerve endings] Olfactory bulb Olfactory nucleus, hypothalamus & thalamus
Reda Kamel, M.D.
1. Air conditioning of the inspired air. 2. Reduce the weight of the skull. 3. Vocal resonance. 4. Thermal insulation of the skull base. Nasal Cycle Nasal mucosa undergoes rhythmic cyclical congestion and decongestion, thus controlling the airflow through nasal chambers. Nasal cycle varies every 2-4 hours.
I. Nasal obstruction: Anatomical abnormality: Congenital choanal atresia or deviated nasal septum. Abnormality of the mucous membrane: Nasal polyposis or turbinate hypertrophy. Abnormalities of autonomic control of the mucosa: Vasomotor rhinitis.
Symptomatology: Bilateral Obstruction Nasal
Bil. Choanal atresia
Foreign bodyAccident: Fracture- Haematoma
Iatrogenic: Pack-Haematoma
Acute nonspecific: Common cold-Abscess
Acute specific: Diphtheria
Chronic nonspecific: At. - Hypertrophic
Chronic specific: $ – T.B. - Scleroma Benign: Ostioma -papilloma
Malignant: Carcinoma - Sarcoma
Polyps
Allergy
Deviated septum
1- Congenital
2- Traumatic
3- Inflammatory
4- Neoplastic
5- Others
II. Nasal Discharge: -Watery clear discharge: Onset of common cold, allergic rhinitis or CSF rhinorrhea. -Mucopurulent: Yellow pus: Sinusitis. Unilateral foul discharge in a child: FB in the nose. Crusts in adults: Atrophic rhinitis. -Thick blood stained discharge: Tumour. -Postnasal mucopurulent discharge: Disease of the posterior group of sinuses.
III. Sneezing: Allergic rhinitis or common cold. IV. Pain: Severe local pain: Folliculitis. Early morning headache: Sinusitis. V. Epistaxis.
VI. Disturbance of smell: 1. Anosmia and hyposmia: Complete or partial loss of the sense of smell. It is often described as loss of taste as flavours are largely perceived through the olfactory apparatus. The causes are: -Nasal obstruction from common cold or nasal polyposis. -Vasomotor rhinitis. -Peripheral neuritis particularly following influenza virus. -Atrophic rhinitis. -Trauma: Base of skull fracture involving the cribriform plate.
2. Cacosmia: The perception of a bad smell. The causes are: -Maxillary sinusitis. -Foreign body in the nose. -Chronic suppurative otitis media. Pus discharge through Eustachian tube.
3. Parosmia: The perversion of the sense of smell or subjective sensation of non-existing odours. Causes: Functional. Organic. -Influenzal neuritis. -Epileptic aura. -Drugs: Streptomycin.
Investigations: Differential diagnosis
CTEndoscopy
Reda Kamel, M.D.
Endoscopic Nasal Examination
Nasal SeptumInferior Turbinate
*
*