Kaan Yücel M.D., Ph.D. 5.January.2011 Thursday Structures inside the temporal fossa: 1) Temporal muscle 2) Temporal fascia (overlies the temporalis muscle) 3) Superficial temporal artery (br. of external carotid) 4) Superficial temporal vein (unites with the maxillary vein to form the retromandibular vein) 5) Auriculotemporal nerve (br. of mandibular nerve which is a br of the trigeminal nerve) A knowledge of the anatomy of the infratemporal and pterygopalatine fossae and their contents is essential for understanding the dental region. Many of the nerves and blood vessels supplying the structures of the mouth run through or close to these fossae. In addition, the infratemporal fossa contains the pterygoid muscles which play an important part in movements of the mandible. Infratemporal Fossa Irregularly shaped space deep and inferior to the zygomatic arch, deep to the ramus of the mandible and posterior to the maxilla. Communicates with the temporal fossa through the interval between (deep to) the zygomatic arch and (superficial to) the cranial bones. Temporal fossa is superior to the zygomatic arch, The infratemporal fossa is inferior to the zygomatic arch. The boundaries of the infratemporal fossa Laterally: ramus of the mandible Medially: lateral pterygoid plate Anteriorly: posterior aspect of the maxilla Posteriorly: tympanic plate ,mastoid and styloid processes of the temporal bone Superiorly: the inferior (infratemporal) surface of the greater wing of the sphenoid Inferiorly: where the medial pterygoid muscle attaches to the mandible near its angle The infratemporal fossa contains the: 1) 2) 3) 4) 5) 6) Inferior part of the temporalis muscle Lateral and medial pterygoid muscles Maxillary artery Pterygoid venous plexus Mandibular, inferior alveolar, lingual, buccal, chorda tympani nerves Otic ganglion Neurovasculature of the infratemporal fossa • The maxillary artery is the larger of the two terminal branches of the external carotid artery. • It arises posterior to the neck of the mandible and is divided into three parts based on its relation to the lateral pterygoid muscle. 1st (mandibular) part: Deep to the condyle of mandible 2nd (pterygoid) part: Neighbourhood of lateral pterygoid muscle 3rd (pterygopalatine) part: Inside the infratemporal fossa (extends into the pterygopalatine fossa) Branches of the 1st part: 1) Deep auricular (to external acoustic meatus) 2) Anterior tympanic artery (to the tympanic membrane) 3) Middle meningeal (to dura mater and calvaria) 4) Accessory meningeal aa. (to the cranial cavity) 5) Inferior alveolar artery (to the mandibular gingiva and teeth) Branches of the 2nd part: 1) 2) 3) 4) Deep temporal aa. (to the temporal muscle) Pterygoid aa. (to the pterygoid muscles) Masseteric artery (to the masseter muscle) Buccal artery (to the buccinator muscle) o o o o o o o o o o o deep auricular (da) anterior tympanic (at) middle meningeal (mm) accessory middle meningeal (amm) inferior alveolar (ia) buccal (b) deep temporal (dt) posterior superior alveolar (psa) descending palatine (dp) infraorbital (io) sphenopalatine (sp) Pterygoid venous plexus Located partly between the temporalis and the pterygoid muscles. The venous equivalent of most of the maxillary Actually a network of veins formed by the veins following the branches of maxillary artery. Mandibular nerve Arises from the trigeminal ganglion in the middle cranial fossa. Immediately receives the motor root of the trigeminal nerve Leaves the cranium through the foramen ovale into the infratemporal fossa. Mandibular nerve The mandibular nerve contains GSA and SVE fibers. Branches of CN V3 supply the four muscles of mastication but not the buccinator, which is supplied by the facial nerve. Branches within the infratemporal fossa is divided into three groups: 1) Branches arising from the trunk Spinous nerve Medial pterygoid nerve 2) Anterior branches Buccal nerve Masseteric nerve Deep temporal nerves Lateral pterygoid nerve 3) Posterior branches Auriculotemporal nerve Lingual nerve Inferior alveolar nerve The spinous nerve passes through the spinous foramen and enters the cranium. It is a sensory nerve innervating the dura mater. The medial pterygoid nerve innervates the medial pterygoid muscle, tensor veli palatini muscle and the tensor tympani muscle. Buccal nerve, masseteric nerve, deep temporal nerves, lateral pterygoid nerve innervate the muscles with the same name except the buccal nerve. Buccal nerve is sensory and innervates the inner surface of the cheek. Auriculotemporal nerve Supplies sensory fibers to the auricle and temporal region. Also sends articular (sensory) fibers to the TMJ. Conveys postsynaptic parasympathetic secretomotor fibers from the otic ganglion to the parotid gland. The inferior alveolar nerve enters the mandibular foramen and passes through the mandibular canal, forming the inferior dental plexus, which sends branches to all mandibular teeth on its side. The terminal branch of the inferior alveolar nerve is the mental nerve which passes through the mental foramen. Lingual nerve sensory to the anterior two thirds of the tongue, the floor of the mouth, and the lingual gingivae. o deep temporal (dt) o auriculotemporal (at) o inferior alveolar (ia) o nerve to the mylohyoid (nmh) o lingual (l) o buccal (b) o branches to lateral pterygoid (not labeled) o Not shown: meningeal branch o nerve to masseter Chorda tympani nerve A branch of CN VII carrying taste fibers from the anterior two thirds of the tongue. Joins the lingual nerve in the infratemporal fossa. Also carries secretomotor fibers for the submandibular & sublingual salivary glands. Otic ganglion (parasympathetic) Located in the infratemporal fossa, just inferior to the foramen ovale. Presynaptic parasympathetic fibers, derived mainly from the glossopharyngeal nerve (via the lesser petrosal nerve), synapse in the otic ganglion. Postsynaptic parasympathetic fibers, secretory to the parotid gland, pass from the otic ganglion to this gland through the auriculotemporal nerve. auriculotemporal nerve glossopharyngeal nerve (via the lesser petrosal nerve) Pterygopalatine Fossa A small space behind and below the orbital cavity. An inverted 'tear-drop' shaped space between bones on the lateral side of the skull immediately posterior to the maxilla. Although small in size, the pterygopalatine fossa communicates via fissures and foramina in its walls with: 1) the middle cranial fossa 2) infratemporal fossa 3) floor of the orbit 4) lateral wall of the nasal cavity 5) oropharynx 6) roof of the oral cavity 7 foramina and fissures provide apertures through which structures enter and leave the pterygopalatine fossa: foramen rotundum & pterygoid canal middle cranial fossa palatovaginal canal nasopharynx palatine canal leads oral cavity (hard palate) sphenopalatine foramen nasal cavity pterygomaxillary fissure infratemporal fossa inferior orbital fissure orbit Gateways Because of its strategic location, the pterygopalatine fossa is a major site of distribution for the maxillary nerve [V2] and for the terminal part of the maxillary artery. + parasympathetic fibers from the facial nerve [VII] Sympathetic fibers from the T1 spinal cord level joinining the branches of the maxillary nerve [V2] in the pterygopalatine fossa. All the upper teeth receive their innervation and blood supply from the maxillary nerve [V2] and the terminal part of the maxillary artery, respectively, that pass through the pterygopalatine fossa. Skeletal framework The walls of the pterygopalatine fossa are formed by parts of the palatine, maxilla, and sphenoid bones: • anterior wall is formed by the posterior surface of the maxilla; • medial wall is formed by the lateral surface of the palatine bone; • posterior wall and roof are formed by parts of the sphenoid bone. The part of the sphenoid bone that contributes to the formation of the pterygopalatine fossa is the anterosuperior surface of the pterygoid process. Opening onto this surface are two large foramina: • maxillary nerve [V2] through foramen rotundum middle cranial fossa • greater petrosal nerve from the facial nerve [VII] + sympathetic fibers internal carotid plexus join to form the nerve of the pterygoid canal that passes into the pterygopalatine fossa through the anterior opening of the pterygoid canal. The pterygoid canal is a bony canal opening onto the posterior surface of the pterygoid process. The pterygoid canal opens into the middle cranial fossa just anteroinferior to the internal carotid artery as the vessel enters the cranial cavity through the carotid canal. The contents of the pterygopalatine fossa 1) 2) 3) 4) Third part (pterygopalatine part) of the maxillary artery Maxillary nerve Nerve of the pterygoid canal (Vidian’s nerve) Pterygopalatine ganglion Lacrimal Gland Consists of a large orbital part and a small palpebral part. Situated above the eyeball in the anterior and upper part of the orbit posterior to the orbital septum. Opens into the lateral part of the superior fornix of the conjunctiva. Innervation of the lacrimal gland The parasympathetic secretomotor nerve supply is derived from the lacrimal nucleus of the facial nerve. The preganglionic fibers reach the pterygopalatine ganglion via the nervus intermedius and its great petrosal branch. The postganglionic parasympathetic and sympathetic fibers leave the zygomaticotemoral branch of the zygomatic nerve and form a special autonomic nerve, which joins the lacrimal nerve. The lacrimal nerve is a major general sensory branch of the ophthalmic nerve [V1]. The postganglionic parasympathetic and sympathetic fibers pass with the lacrimal nerve to the lacrimal gland. Maxillary Nerve (V2) Purely sensory Originates from the trigeminal ganglion in the cranial cavity Exits the middle cranial fossa Enters the pterygopalatine fossa (foramen rotundum) Exits as the infra-orbital nerve (inferior orbital fissure) Gives sensory fibers to the skin of the face and the side of the nose. Maxillary Nerve (V2) Branches Within the fossa, the maxillary nerve is attached to the pterygopalatine ganglion by two ganglionic branches. Sensory fibers from the nose, the palate, and the pharynx. Postganglionic parasympathetic fibers to the lacrimal gland. More anteriorly posterior superior alveolar nerves are given off. Pass through the pterygopalatine maxillary fissure into the infratemporal fossa. Here they divide into numerous small branches • Enter the maxilla through the posterior alveolar foramina Supply the upper molar teeth, the mucous membrane on the buccal surface of the associated alveolar process and the lining of the maxillary sinus. Anesthesia of the upper molar teeth and associated buccal mucosa can be achieved by a posterior superior alveolar block. As the maxillary nerve is about to enter the inferior orbital fissure it gives rise to the zygomatic nerve. divides into: Zygomaticotemporal branch passing into temporal fossa to supply skin of the temple Zygomaticofacial nerve supplies skin over the prominence of cheek. Pterygopalatine Ganglion (Ganglion pterygopalatinum, Meckel's ganglion, Nasal ganglion, Sphenopalatine ganglion) Largest of the 4 parasympathetic ganglia in the head Formed by the cell bodies of the postganglionic neurons associated with preganglionic parasympathetic fibers of the facial nerve [VII] carried by the greater petrosal nerve and the nerve of the pterygoid canal. Pterygopalatine Ganglion The postganglionic fibers, together with sympathetic fibers, join fibers from the ganglionic branches of the maxillary nerve [V2]. Postsynaptic fibers arising from the pterygopalatine ganglion supply the lacrimal gland as well as nasal glands and minor salivary glands within the oral cavity. The postsynaptic fibers innervating the lacrimal gland pass to the lacrimal nerve to reach the lacrimal gland. Branches • Orbital branches, enter the orbit (inferior orbital fissure) Supply of the orbital wall and of the sphenoidal and ethmoidal sinuses. • Greater and lesser palatine nerves, supply the palate, the tonsil, and the nasal cavity. The greater palatine nerve originates from the geniculate ganglion of the facial nerve [VII] in the temporal bone. In the palatine canal, gives origin to posterior inferior nasal nerves, which contribute to the innervation of the lateral nasal wall. Greater petrosal nerve enters the pterygoid canal and becomes the nerve of the pterygoid canal • Pharyngeal branch, which supplies the roof of the nasopharynx 1. 2. 3. 4. 5. 6. 7. infraorbital nerve posterior superior alveolar nerve pterygopalatine ganglion (parasympathetic) greater palatine nerve lesser palatine nerve cut nasopalatine nerve nerve of the pharyngeal canal Maxillary Artery A major branch of the external carotid artery in the neck. Passes through the infratemporal fossa Enters the pterygopalatine fossa through the pterygomaxillary fissure. Branches of the third part of the maxillary artery 1) 2) 3) 4) 5) 6) Posterior superior alveolar artery Infra-orbital artery Greater palatine artery Pharyngeal artery Sphenopalatine arteries Artery of the pterygoid canal Collectively, these branches supply much of the nasal cavity, the roof of the oral cavity, and all upper teeth. In addition, they contribute to the blood supply of the sinuses, oropharynx, and floor of the orbit. The maxillary artery gives off the posterior superior alveolar branch as it enters the pterygopalatine fossa. Runs with the corresponding branches of the maxillary nerve to suppy the upper posterior teeth and adjacent structures. MAXILLARY ARTERY MNEMONICS IDAMA 1ST PART Inferior alveolar artery Deep auricular Anterior tympanic artery Middle meningeal Accessory meningeal aa. Mehmet 2ND PART Polat Deniz Buca Masseteric artery Pterygoid aa. Deep temporal aa. Buccal artery PIG SAP 3RD PART Posterior superior alveolar artery Infra-orbital artery Greater palatine artery Sphenopalatine arteries Artery of the pterygoid canal Pharyngeal artery Veins The veins pass through the pterygomaxillary fissure to join the pterygoid plexus of veins in the infratemporal fossa.