Anatomy lecture #: 9 Date: 8/3/2011 Tuesday Dr. maher al-hadidi Infratemporal fossa TOPICS: boundaries contents Last lecture we start talking about the infratemporal fossa, which is a small space that is located medial to the ramus of the mandible. Boundaries: 1) Lateral wall formed by the ramus of the mandible. 2) Medial wallformed by the lateral pterygoid plate. 3) Roof (superior wall) formed by the inferior surface of greater wing of sphenoid bone. ** It contains 2 foramina, foramen spinosum and foramen ovale. 1 Behind foramen spinosum there is a spine which is called spine of sphenoid. 4) Posterior wallformed by the styloid process and by the articular process of the mandible (head & neck). 5) Anterior wall formed by the infratemporal part of maxilla. ** Which has posterior superior alveolar foramen for the posterior superior alveolar artery and nerve, and tuberosity of maxilla. {These 2 structures are important and we shouldn't forget them} Between pterygoid and maxilla there is an opening pterygomaxillary fissure (entrance of maxillary artery and other important structures) that leads to pterygopalatine fossa. Contents: 1) 3 muscles lateral pterygoid muscle , medial pterygoid muscle , temporalis muscle (narrowest part of it, this muscle is also located in the temporal fossa) 2) 1 ligament sphenomandibular ligament extending from the spine of sphenoid reaching the mandible. 3) 1 arterymaxillary artery. 4) 2 veinsmaxillary vein, pterygoid venous plexus. 5) 3 nervesmandibular nerve (v3) through foramen ovale. Chorda tympani of the facial nerve (special sensation for the taste buds of anterior 2/3 of the tongue) passing with lingual nerve (general sensation) Otic ganglion (parasympathetic secretomotor fibers to Parotid gland) *Note: all ganglia in head & neck are parasympathetic except the 3 pair of sympathetic ganglia in the neck superior, middle, inferior. **To make things clear: trigeminal nerve originates from the pons, trigeminal ganglion isn't inside the brain, it's outside the brain but inside the skull, it's formed between the brain the cranial cavity on the lateral side of cavernous sinus to give codes to it's 3 branches before division. 2 Now we are going to talk about the contents in details starting with the muscles: After removing ramus of the mandible, coronoid process. **lateral pterygoid muscle It has 2 heads and it's triangular in shape. *Origin: -upper headinfratemporal part of the greater wing of sphenoid. -lower head lateral (outer) surface of lateral pterygoid plate, wedged between two heads of medial pterygoid muscle. *Insertion: 1.pterygoid fossa of mandibular neck. 2. Temporomandibular joint (TMJ) capsule. 3. Articular disk of TMJ (TMJ is 2 joints in one joint between the mandibular fossa of temporal bone and the head of mandible, but there is no direct contact between them due to the presence of the articular disk and that's why all the synovial joints in our body are made of hyaline cartilage except the articular disk it's a fibrocartilage excessive movement. 3 The upper/superior joint which is between the upper surface of articular disk and the mandibular fossa is for forward and backward movements, lower/inferior joint which is between the lower surface of articular disk and the head of mandible is for hinge movements up and down.) *Action: (DP) 1) Depression. 2) Protrusion, but mainly protrusion. 3) Pushes the mandible to the opposite side in side-toside movement. **We can't do protrusion without depression in order to open our mouth *Nerve supply: nerve to lateral pterygoid muscle from (V3) **don’t forget that the nerve supply of all the muscles of mastication through the motor branches of mandibular nerve. ** Lateral pterygoid muscle is sandwiched between the 2 heads of medial pterygoid muscle. **Medial pterygoid muscle It has 2 heads. 4 *Origin: -Deep (large) head medial (inner) surface of lateral pterygoid plate. -Superficial (small) head tuberosity of maxilla. ** SO there are 2 muscles attached to the lateral pterygoid plate from outside lateral pterygoid muscle and from inside medial pterygoid muscle. (Laterally: lateral pterygoid and medially: medial pterygoid.) *Insertion: inner surface of the ramus and angle of mandible. *Action: (ES) 1) Elevation. 2) Side-to-side movements of mandible. **side-to-side movements are done by 2 muscles: medial and lateral pterygoid muscles by alternating action between them. (V3). *Nerve supply: nerve to medial pterygoid from mandibular nerve Now we will talk about maxillary artery: **Maxillary artery 5 ** Common carotid arteryexternal carotid arterymaxillary artery (large branch) superficial temporal artery. ** External carotid artery ascends upward opposite to the neck of the mandible through the parotid gland. **The maxillary artery is the largest branch of external carotid artery. **Starts behind the neck of mandible, it passes medial and deep to the neck of mandible. **It passes external or internal to lateral pterygoid muscle but most of the time externally, after crossing the lateral pterygoid it will disappear by entering pterygomaxillary fissure to reach pterygopalatine fossa in order to accompany it's twin maxillary nerve which innervates all the area that is derived from maxillary process, and we also have pterygopalatine ganglion that gives the maxillary nerve it's code as secretomotor (parasympathetic) for the palate,mouth and nose. **lateral pterygoid muscle divides the maxillary artery into 3 parts: 1) first(mandibular)partit gives 5 branches that pass through spaces: *inferior alveolar artery (enter through mandibular canal). *middle meningeal artery (enter though foramen spinosum). *accessory middle meningeal artery (enter through foramen ovale). *anterior tympanic artery (tympanic membrane). *deep auricular artery (external auditory meatus). 2) Second (pterygoid) parton the outer and lateral surface of the lateral pterygoid muscle, it gives mascular branches to medial and lateral pterygoid muscle, masseter muscle and to temporalis muscle. Branches: * deep temporal artery. *lateral pterygoid artery. *medial pterygoid artery. *massetric artery. *buccal artery. 6 3) Third (pterygopalatine) part it gives branches to accompany the branches of the maxillary nerve (v2). ** To make things clear: the origin of sympathetic fibers from thoracolumber region and then they ascend upward (because there is no ganglia there) to reach structures of head &neck in the superior,middle,inferior cervical sympathetic ganglia, these ganglia give branches of sympathetic fibers around arteries and specially around the internal carotid artery which enters the skull through the canal and cavernous sinus to the brain. ** Hay-fever: it is an allergic inflammation of the nasal airways (mouth, nose, palatine), it affects the pterygopalatine ganglion commonly caused by pollens of olives and treated by giving antihistaminic drugs. "Wherever smart people work, doors are unlocked." =) Done by: Saba hawamdeh 7