Anatomy III: Blood and the Cardiovascular and Respiratory Systems - Lesson 2 - Nostrils and Pharynx

Anatomy III: Blood and the Cardiovascular and Respiratory Systems Antoni Alegre Martinez 6 CM Lesson 2 Nostrils and pharynx 2 Nose Entry to the respiratory tract It is superior to the hard palate It also contains the organ...

Anatomy III: Blood and the Cardiovascular and Respiratory Systems Antoni Alegre Martinez 6 CM Lesson 2 Nostrils and pharynx 2 Nose Entry to the respiratory tract It is superior to the hard palate It also contains the organ of smell The nasal septum divides the nasal cavity in right and left Functions of the nose: – Smelling – Respiration – Filtration of dust – Humidification – Reception and secretions from the paranasal sinuses and nasolacrimal ducts 3  Its skeleton is mainly cartilaginous External nose Dorsum of the nose: from the root to the apex Nostrils: two openings in the inferior surface of the nose. They limit laterally with the wings of the nose The cartilages of the nose are covered by thick skin with sebaceous glands, except the superior part of the nose that is bony and covered by thin skin The skin ends at the vestibule of the nose, where it has moist vibrissae that filter the dust particles 4 Skeleton of external nose Bony part of the nose: Nasal bone Frontal processes of the maxillary bone Nasal part of the frontal bone Bony part of the nasal septum Cartilaginous part of the nose: Two lateral cartilages Two alar cartilages, U-shaped, with free movement, they can close the nostrils One septal cartilage 5 Muscles of nose These muscles are not very important in humans, but they are essential in certain animals (elephants, rabbits, diving mammals)… The only meaning in the human is related to the facial expression or aesthetic look – Habitual nasal breathers may be able to flare their nostrils – Habitual mouth breathers normally eliminates their ability to flare the nostrils. In children it can develop into dental malocclusion There are some anti-snoring devices that flare the nostrils and maintain opened the airway 6 Skeleton of external nose Nasal septum: divides the nasal cavity in two cavities. Two parts: Bony part: – Perpendicular plate of the ethmoid bone forms the superior part of the septum, descending from the cribiform plate and continuing as crista galli – Vomer: flat and thin bone, it is the postero- inferior part of the septum Cartilaginous part: mobile and soft, it articulates with the edges of the bony part 7 Nasal cavity The nostrils are the entry to the nasal cavities The cavities are opened posteriorly to the nasopharynx through the choanae The nasal vestibule is lined with skin Thee cavities are lined with mucosa, firmly attached to the periosteum and perichondrium, and continuous with the nasopharynx and paranasal sinuses – The superior third of the nasal mucosa is the olfactory area for the smell sense – The inferior two thirds of the nasal mucosa are the respiratory area, where the air is warmed and moistened before passing to the superior respiratory tract 8 Nasal cavity Medial view 9 Nasal cavity limits Roof: it is formed by three bones, from anterior to posterior: – Frontal: here the roof is curved and narrow – Ethmoid – Sphenoid: here the roof is plain and wide Floor: formed by two bones: – Palatine process of maxilla – Horizontal plates of the palatine bone Medial wall: the septum Lateral wall: irregular due to the nasal conchae 10  Nasal cavity limits Lateral part (conchae) Medial part (septum) 11 Features of nasal cavities There are three nasal conchae hanging from the lateral wall: superior, middle, and inferior They have many valleys and convolutions for increase the area of heat exchange. Their mucosa is very sensitive to the infection or irritation, and it can very quickly swell for block the entry of air in the affected side Inferior concha: the biggest one, formed by an independent bone called inferior concha bone lined with a highly vascularized mucosa Middle and superior conchae: formed by the ethmoid bone, also covered by a mucosa. When the middle concha is removed we can see the ethmoidal bulla, formed by middle ethmoidal cells 12  Check how small is the superior concha. It is anterior to the sphenoidal sinus Check how the inferior and middle conchae cover the inferior and middle meatus, and also how they divide the wall into three equal parts Check that the inferior concha almost ends at the Eustaquian tube 13 Nasal cavities with the conchae dissected Medial view 14  Nasal cavities Medial view Check the communications of the nasal cavity with the sinuses: The sphenoidal sinus opens into the spheno- ethmoidal recess The orifices of posterior ethmoidal cells open into the superior meatus The orifices of middle and anterior ethmoidal cells open into the semilunar hiatus → middle meatus 15 Nasal meatus The meatus are the opening of the sinuses and the ducts to the nasal cavity: Spheno-ethmoidal recess: located posterosuperior to the superior concha. It receives the opening of the sphenoidal sinus, a cavity in the body of the sphenoid – The roof of the spheno-ethmoidal recess is the cribriform plate Three nasal meatus: located laterally – Superior – Middle – Inferior 16  Three nasal meatus: located laterally: Nasal meatus Superior nasal meatus: narrow track between the superior and the middle nasal conchae. It receives the opening of the posterior ethmoidal cells Middle nasal meatus: longer and deeper than the superior. It contains the semilunar hiatus, where drain: – The frontal sinus, through the frontonasal duct → Ethmoidal infundibulum → Semilunar hiatus – The maxillary sinus → Semilunar hiatus (sometimes can go first to infundibulum) – The anterior and middle ethmoidal cells directly to the Semilunar hiatus Inferior nasal meatus: infero-lateral to the inferior nasal concha. Here drains the nasolacrimal duct that guides the tears from the lacrimal sac 17 Lateral wall with conchae cut 18 Coronal section of the right side of the head 19 Vessels of the nose Arterial supply: Anterior and Posterior ethmoidal artery, from the ophthalmic artery. They divide into lateral and medial/septal branches. The anterior branch also irrigates the external nose Sphenopalatine artery, from the maxillary artery. It divides into lateral and medial/septal branches Greater palatine artery, from the maxillary artery. It reaches the septum through the incisive canal of the anterior hard palate Septal branch of the superior labial artery, from the facial artery. It also irrigates the external nose The septum has at its anterior part an anastomotic arterial plexus involving all this five arteries (Kiesselbach area) 20  Arterial supply The most important arteries are the sphenopalatine artery (from the maxillary) and anterior ethmoidal artery (from the ophtalmic). Check the Kiesselbach area 21 Veins of the nose Venous drainage: Small veins form a rich submucosal plexus deep to the nasal mucosa, very useful for the thermoregulation of the body and for warm the incoming air These veins will drain into the: – Spheno-palatine vein – Facial vein – Ophthalmic vein The external nose will drain to the facial vein 22 Nerves of the nose Dorsum and apex of the nose is innervated by infratrochlear nerve from V1 Alae of the nose are innervated by infraorbital nerve from V2 The nervous territory of the inner nose is divided in two parts by an imaginary line passing through the anterior nasal spine to the spheno-ethmoidal recess, obtaining: – Postero-inferior region – Anterosuperior region 23 Nerves of the nose Innervation of inner nose: Postero-inferior region: sensory is received by two branches from the maxillary nerve: – Nasopalatine nerve: for the nasal septum – Greater palatine nerve: for the lateral wall Anterosuperior region: sensory is received by ethmoidal nerves – They are branches from the nasociliary nerve Which is a branch from the ophthalmic nerve 24  Nerves of the nose The spotted line marks the difference of the territory of the V1 Ophtalmic and the V2 Maxillary nerves. Check the position of the olfactory bulb 25 Sense of smell The olfactory epithelium is located in the superior part of the lateral and septal walls It sends nervous cells that form the olfactory nerve and pass through the cribiform plate for end at the olfactory bulb 26 Paranasal sinuses Hollow extensions of the respiratory system inside of some bones. The sinuses receive the name of their corresponding bone Frontal Ethmoidal Sphenoidal Maxilary Functions: Reduce the weight of the skull Increase the surface of mucosa Serve as resonance chambers for phonation 27  Paranasal sinuses in X-Ray F: Frontal sinus CG: Crista Galli E: Ethmoidal cells M: Maxillary sinuses HP: Hard Palate OC: Oral cavity 28 Paranasal sinuses Frontal sinuses: Right and left, with a septum in the middle Normally they are not symmetrical They are located posterior to the superciliary arches They drain into the ethmoidal infundibulum thanks to the frontonasal duct – Gravity helps in the drainage of the sinuses They are innervated by the supra-orbital nerves 29 Sphenoidal sinuses: Right and left, with a septum Located in the body and wings of the sphenoid, posterior to the ethmoidal cells The bony wall is very fragile and very important because it separates the mucosa from the optic nerves, chiasm, pituitary gland and internal carotid arteries They drain to the spheno-ethmoidal recess Arterial supply: posterior ethmoidal arteries Nerve supply: posterior ethmoidal nerves 30 Ethmoidal sinuses: Small caves of the mucous membrane Located next to the middle and superior nasal meatus Separated from the orbit by the thin and delicate lamina papyracea Innervated by the ethmoidal branches of the nasociliary nerves Drainage: Anterior ethmoidal cells: drain to the semilunar hiatus → middle nasal meatus Middle ethmoidal cells: form the ethmoidal bulla and drain to the semilunar hiatus → middle nasal meatus Posterior ethmoidal cells: open to the superior meatus 31 Maxillary sinuses: The largest ones, with these limits: – Base: inferior part of the lateral wall of the nasal cavity – Roof: floor of the orbit – Floor: alveolar part of the maxillary bone They drain through infundibulum → semilunar hiatus → middle nasal meatus – This drainage runs against gravity, so it is very common to have chronic maxillary sinusitis Arterial supply: superior alveolar branches of the maxillary artery Innervation: anterior, middle, and posterior superior alveolar nerves – They are branches of the maxillary nerve 32 Paranasal sinuses 33 Pharynx 34 Pharynx It forms part of the digestive system and respiratory system It is posterior to the nasal and oral cavities Superior limit: cranial base Inferior limit: inferior border of the cricoid cartilage (level of C6) where it continues with the esophagus Posterior limit: the posterior wall lies at the prevertebral layer of deep cervical fascia Its widest width is at the hyoid bone (5 cm diameter) Its tighter width is at the inferior end (1,5 cm diameter) 35  Pharynx Pharynx opened by a cut in the midline of the posterior wall Check the choanas (opening to the nose), the opening to the mouth, and the laryngeal inlet (opening to the larynx) Check the piriform fossa, an invagination of the larynx into the anterior wall 36 Pharynx The pharynx is divided into three parts: Nasopharynx: the part of pharynx behind the nose, it is superior to the soft palate Oropharynx: the part of pharynx behind the mouth, it is inferior to the soft palate Laryngopharynx: the part of pharynx behind the larynx 37 Nasopharynx Nasopharynx: Respiratory function It is located posterior to the nasal cavities The nasal cavities open to the nasopharynx through two choanae The roof of the nasopharynx is in contact with the surface of the sphenoid bone and the basilar part of the occipital bone This roof is continuous with the posterior wall of the nasopharynx, where we can find the pharyngeal tonsil 38 Nasopharynx Salpingo-pharyngeal fold: – It is a fold that covers the salpingo-pharyngeus muscle from the Eustaquian tube – Eustaquian tube is also called pharyngo-tympanic tube – The fold is useful for open and close the Eustaquian tube during swallowing Near the opening of the Eustaquian tube there are the tubal tonsils 39  Bartolomeo Eustachi San Severino ~1510, Rome 1574 He discovered the suprarrenal glands He invented the name “vena cava” He discovered many of the structures in the hearing and the teeth: cochlea, stapedius, etc. His book “Tabulae anatomicae” is one of the most important anatomy books in history. It influenced the new generations of physicians during centuries 40 One of the pictures from Tabulae Anatomicae 41 Oropharynx Oropharynx Digestive function, the origin of the swallowing It extends from the soft palate to the epiglottis – Superior limit: soft palate – Inferior limit: base of the tongue – Laterally: Palatoglossal arch and palatopharyngeal arch The oropharynx allows deglutition after the mastication in three stages: 42 Oropharynx Stages of the deglutition: 1. Voluntary: thanks to the movements of the tongue and soft palate, the bolus is compressed against the bony palate and pushed from the mouth into the oropharynx 2. Involuntary and quick: the soft palate elevates for seal the nasopharynx from oropharynx and laryngopharynx 3. Involuntary: the three pharyngeal constrictor muscles contract sequentially creating a peristaltic wave that guides the bolus into the esophagus 43 Laryngopharynx Located at C4-C6 level Posterior to the larynx From the superior border of the epiglottis to the inferior border of the cricoid cartilage Below the cricoid, it continues with the esophagus 44 Laryngopharynx Piriform fossa: cave on the laryngo-pharyngeal cavity on either side of the laryngeal inlet The fossa and the inlet are separated by the ary-epiglottic fold. It is also separated medially by the thyroid cartilage and the thyro-hyoid membrane In this fossa are located the internal laryngeal and recurrent laryngeal nerves, very easy to damage if an external body achieves the fossa 45  Check the piriform fossa 46 Pharyngeal muscles External circular layer: three involuntary muscles that contract sequentially: Superior pharyngeal constrictor Middle pharyngeal constrictor Inferior pharyngeal constrictor Internal longitudinal layer: Palatopharyngeus Stylopharyngeus Salpingopharyngeus 47 Pharyngeal muscles Insertions of the pharyngeal muscles: Superior constrictor: pterygoid process of sphenoid bone, pharyngeal tubercle of occipital bone, and mandible Middle constrictor: Hyoid bone Inferior constrictor: Cricoid and thyroid cartilages Palatopharyngeus: Soft palate Stylopharyngeus: Styloid process of temporal bone Salpingopharyngeus: Eustaquian tube 48 Check the three constrictor muscles also in the lateral view 49 Pharyngeal muscles The constrictor muscles have: – A strong internal fascial lining, the pharyngobasilar fascia – A thin external fascial lining, the buccopharyngeal fascia, that blends inferiorly with the pretracheal layer of deep cervical fascia They are innervated by branches from: – Parasympathetic fibers: from vagus nerve – Sympathetic fibers: from the superior cervical ganglion 50 Pharyngeal muscles There are four gaps in the musculature of the pharynx due to the overlapping of the three muscles: First gap: superior to the superior pharyngeal constrictor muscle. Here cross the Eustaquian tube and the Ascending palatine artery Second gap: between the superior and middle pharyngeal constrictors. Here cross the Stylopharyngeus, IX Glossopharyngeal nerve, and Stylohyoid ligament to the interior of the pharynx Third gap: between the middle and inferior pharyngeal constrictors. Here cross the Internal laryngeal nerve and Superior laryngeal artery and vein Fourth gap: Inferior to the inferior pharyngeal constrictor, where crosses the recurrent laryngeal nerve 51 Gaps of Pharynx 52 Constrictor muscles Posterior view 53 Vessels of pharynx Arteries: a lot of vessels, but all of them from external carotid: Ascending pharyngeal Ascending palatine Tonsillar branches of the facial artery Small branches from maxillary and lingual arteries However the inferior part can be irrigated by inferior thyroid artery, from thyrocervical trunk, from subclavian artery 54 Confused about palatine and pharyngeal arteries? Palatine arteries: Maxillary artery gives the descending, greater and lesser palatine arteries Facial artery gives the ascending palatine artery An anastomotic circle is formed between them Pharyngeal arteries: External carotid artery gives the ascending pharyngeal artery Maxillary artery gives a pharyngeal branch that crosses the palatovaginal canal There is no descending pharyngeal artery Pharynx is not only irrigated by the pharyngeal arteries: participation of the lingual, facial and even inferior thyroid arteries 55 Vessels of pharynx Veins: Pharyngeal plexus → Pterygoid plexus → Facial vein → Internal jugular veins Lymph: Deep cervical nodes Retropharyngeal nodes Paratracheal nodes Infrahyoid nodes 56 Pharyngeal nerves There is a pharyngeal nervous plexus Motor fibers come from X Vagus nerve, giving a pharyngeal branch that innervates all the muscles of the pharynx except: – Stylopharyngeus, that is innervated by IX Glossopharyngeal nerve – Tensor veli palatini, that is innervated by V3 mandibular nerve The inferior pharyngeal constrictor can also receive some motor fibers from the external laryngeal nerve and recurrent laryngeal nerve from the X Vagus nerve The nasopharynx mucosa can receive innervation from the V2 Maxillary nerve Tonsilar nerves come from IX Glossopharyngeal and X Vagus nerves 57 Pharyngeal vessels and nerves 58 Vessels of Palatine tonsil Tonsilar artery: from the facial artery. It irrigates also the palatine tonsil together with other small arteries: ascending palatine artery, lingual artery, descending palatine artery Paratonsillar vein: receives the blood from the soft palate and crosses to the tonsil before entering to the pharyngeal venous plexus The lymph vessels go to the mandible angle to the tonsillar node (also called jugulodigastric node) 59 Test yourself: Can you name the sinuses, meatus and conchae? 60 Test yourself: Can you name the sinuses, meatus and conchae? 61 Bibliography Moore Clinically oriented anatomy 8th edition / Moore, Keith L. Published 2018 Moore Essential Cllinical anatomy 6th edition. Published 2019 Gray's Anatomy for students / Drake, Richard L. 4th Edition Published 2019 Some laminae from “Tabulae anatomicae” are published for free in: http://www.nlm.nih.gov/exhibition/historicalanatomies/eustachi_hom e.html Color atlas of anatomy 7h edition, Rohen, Yokochi Manual de embriología y anatomía general. V Smith Agreda Anatomía: estructura y morfología del cuerpo humano, 4ª Edición, Lippert 62