1-Lateral & medial pterygoids (muscles of mastication). 2-Branches of mandibular N. 3-Otic ganglion. 4- Chorda tympani. 5-Maxillary artery. 6-Pterygoid venous plexus. Contents of infratemporal fossa

Contents of infratemporal fossa : 2-Mandibular Nerve  Origin & course :  It is a mixed N.,formed by 2 roots : Large sensory & Small motor roots.  They unite together in foramen ovale to form the main trunk of mandibular N. (mixed).  The main trunk emerge from skull through foramen ovale to reach infratemporal fossa, then divides into a small anterior & a large posterior division.

Branches from main trunk  Meningeal branch (Nervous Spinosus) – sensory nerve : it enters skull through foramen spinosum (with middle meningeal artery) to supply meninges in middle cranial fossa.  Nerve to medial pterygoid –motor nerve : It gives off 2 branches, which pass without relay through otic ganglion to supply : tensor tympani (middle ear) & tensor vili palatini (soft palate).

Branches from Anterior Division :  2 deep temporal nerves (motor) : enter deep surface of temporalis muscle to supply it.  Masseteric nerve (motor).  Nerve to lateral pterygoid muscle (motor).  Buccal nerve ( sensory) : supplies skin over cheek + mucous membrane lining cheek, (it does not supply buccinator muscle, which is supplied by buccal branch of facial nerve).

Branches from Posterior Division :(mainly sensory) 1-Auriculotemporal nerve (sensory) : - It arises by 2 roots that surround middle meningeal artey, then it ascend in company with superficial temporal vessels behind TM joint. - It gives sensory branches to : skin of auricle, external auditory meatus, tympanic membrane, scalp + parotid gland, TM joint. - It gives postganglionic para- sympathetic secretomotor fibres from otic ganglion, to supply parotid gland.

2-Lingual nerve (sensory) : - It arises from posterior division of mandibular nerve, in front of inferior alveolar N. - It lies deep to lateral pterygoid, where it is joined by chorda tympani nerve (branch of facial N. carrying taste & parasympathetic fibres). - It descends between ramus of mandible & medial pterygoid. -Then, it passes on the inner surface of the socket of lower 3 rd molar tooth (dangerous area during tooth extraction) - It passes into the submandibular region superficial on the lateral surface of hyoglossus, here the sub-mandibular ganglion hangs from it. - It ends by dividing into terminal branches to the tongue to carry general & taste sensation from anterior 2/ 3 of m.m of tongue & floor of mouth. Also, it gives secretomotor para-symp. Fs.to submandibular & sublingual glands.

3- Inferior alveolar N. (mixed) : -It is the largest branch of post.division of mandibular N. - It descends on lateral surface of sphenomandibular ligament. -Then, it enters mandibular canal through mandibular foramen and runs below teeth, supplying the teeth of lower jaw. - Finally it emerges from mental foramen to supply skin of chin (sensory) -N. to mylohyoid (motor) : arises from inferior alveolar N. before it enters the mandibular foramen, it runs in mylohyoid groove of mandible. It ends by supplying mylohyoid m.+ anterior belly of digastric.

3-Otic Ganglion 3-Otic Ganglion  It is a small parasympathetic ganglion that is functionally associated with glosspharyngeal N.  It lies below foramen ovale, medial to mandibular N.  It receives preganglionic para- sympathetic fibres via tympanic branch, tympanic plexus & lesser petrosal N. originate from glossopharyngeal N.(relay in the ganglion).  It sends postganglionic parasympathetic secretomotor fibres via the auriculo-temporal N. to supply the parotid gland.

4-Chorda Tympani 4-Chorda Tympani  It is a branch of facial N., it leaves the middle ear cavity to enter infratemporal fossa through petrotympanic fissure to join lingual N.  It carries secretomotor parasympathetic fibres to submandibular & sublingual salivary glands.  It carries also sensory taste fibres continue with lingual N. from anterior 2/3 of tongue & floor of mouth.

5-Maxillary Artery 5-Maxillary Artery  It arises behind to the neck of mandible within the substance of parotid gland, as the larger of the 2 terminal branches of external carotid artery.  It runs upward and forward, superficial to lower head of lateral pterygoid muscle, then it dips between 2 heads of lateral pterygoid to enter pterygopalatine fossa.  Branches : 1-inferior alveolar artery : follows inf.alveolar N. into mandibular canal. 2-middle meningeal artery : it passes upward between 2 roots of auriculo- temporal N. it enters skull through foramen spinosum to supply meninges. 3-deep auricular artery : to supply external auditory meatus + tympanic membrane. 4-numerous branches to muscles of mastication.

6-Pterygoid venous plexus 6-Pterygoid venous plexus  It is a network of veins lying around and inside the substance of lateral pterygoid muscle.  It is drained posteriorly by maxillary v.  It communicates anteriorly with facial vein through deep facial vein. Maxillary Vein  It drains the posterior end of pterygoid venous plexus.  It runs backward with maxillary artery on medial side of neck of mandible and joins superficial temporal vein within parotid gland to form retromandibular v.

Submandibular Region Submandibular Region  It lies under cover of body of mandible, between mandible & hyoid bone.  It contains the following structures :  Muscles : digastric, mylohyoid, hyoglossus, geniohyoid, genioglossus and styloglossus.  Salivary glands : submandibular + sublingual.  Nerves : lingual, glossopharyngeal, & hypoglossal.  Parasympathetic ganglion : submandibular.  Blood vessels : facial & lingual.  Lymph nodes : submandibular.

Muscles of submandibular region :  1-digastric muscle :  Origin : by 2 bellies -anterior belly : from digastric fossa on the lower border of body of mandible close to symphysis menti. -posterior belly : from medial surface of mastoid process.  Insertion : into the intermediate tendon which is cnnected to hyoid bone by a fibrous loop of deep fascia. This intermediate tendon pierces stylohoid insertion.  Nerve supply : anterior belly : by N.to mylohyoid from mandibular. Posterior belly : by facial N.  Action : depress mandible or elevate hyoid bone during swallowing.

2-mylohyoid muscle :  Origin : flate triangular sheet of muscle arise from mylohyoid line of mandible.  Insertion : the anterior fibres into a median fibrous raphe, the mylohyoid raphe which extends in the median plane from symphysis menti to hyoid bone. The posterior fibres into body of hypoid bone.  Nerve supply : mylohyoid N. from inferior alveolar N.  Action : -they supports tongue & floor of mouth. -they elevate floor of mouth & hyoid bone during 1 st stage of swallowing. -they depress mandible (open mouth) when hyoid bone is fixed.

3-hyoglossus muscle :  Origin :upper border of body and greater cornu of hyoid bone.  Insertion : it lies deep to mylohyoid to be inserted to side of posterior ½ of tongue.  Nerve supply : hypoglossal N.  Action :depresses the tongue. 4-styloglossus muscle :  Origin : styloid process.  Insertion : it passes downward on lateral surface of superior constrictor muscle to insert into side of tongue decussating with hyoglossus m.  Nerve supply : hypoglossal N.  Action : retracts the tongue backward.

5-Geniohyoid muscle :  Origin : inferior mental spine, behind symphysis menti of mandible.  Insertion : into anterior surface of body of hyoid bone.  Nerve supply : 1 st cervical N. via hypoglossal N.  Action : elevate hyoid bone or depress mandible if hyoid bone is fixed. 6-Genioglossus muscle : it is a fan- shaped m.lies medial to hyoglossus m.  Origin : superior mental spine, behind symphysis menti of mandible.  Insertion : into whole length of tongue + superior fs.into tip of tongue + few inferior fs. Into body of hyoid bone.  Nerve supply : hypoglossal N.  Action : 1-single m. : pulls tongue to opposite side. 2-The 2 ms. Protrude the tongue forward.