Title 8. Max artery, Max nerve, Facial nerve,Ganglion.pdf ✅

FCPS, MS,DDS Admission Preparation Program in Dentistry Farmgate 01638885050 Website: www.purebasic.com.bd 1 | P a g e MAXILLARY ARTERY The maxillary artery is the larger terminal branch of the external carotid artery. It arises behind the neck of the mandible, runs horizontally forward up to the lower border of lower head of lateral pterygoid. Now it turns upwards and forwards, crosses the lower head of lateral pterygoid superficially (sometimes deep). After emerging between the two heads of lateral pterygoid it enters the pterygopalatine fossa by passing through pterygomaxillary fissure. Here it ends by giving its terminal branches. The maxillary artery has a wide territory of distribution. It supplies: (a) upperandlowerjaws, (b) muscles of temporal and infratemporal fossae, (c) nose and paranasal sinuses, (d) palate and roof of pharynx, (e) externalandmiddleear, (f) pharyngotympanictube,and (g) duramater. N.B. The maxillary artery enters the infratemporal fossa by passing forwards, between the neck of mandible and the sphenomandibular ligament.
FCPS, MS,DDS Admission Preparation Program in Dentistry Farmgate 01638885050 Website: www.purebasic.com.bd 2 | P a g e Parts and Relations The maxillary artery is divided into three parts by the lower head of lateral pterygoid muscle. The parts are: 1. First part (mandibular part): From beginning (origin) to lower border of lateral pterygoid. It lies between the neck of the mandible laterally and sphenomandibular ligament medially. The auriculotemporal nerve lies above this part. 2. Second part (pterygoid part): From lower border to the upper border of the lower head of lateral pterygoid (i.e., second part lies on or deep to lower head of lateral pterygoid). 3. Third part (pterygopalatine part): From upper border of the lower head of lateral pterygoid to pterygopalatine fossa. In pterygopalatine fossa it lies in front of the pterygopalatine ganglion. N.B. • Most of the branches from the first and second parts of maxillary artery accompany the branches of the mandibular nerve. • Branches from the third part of the maxillary artery accompany the branches of maxillary nerve and pterygopalatine ganglion. • Branches from the second part of the maxillary artery are muscular only and supply muscles of mastication. • All the branches (1st and 3rd part) of the maxillary artery pass through bony foramina and fissures except branches from its second part. . Middle meningeal artery is the largest meningeal branch. It supplies meninges as well as the skull bone. Clinically it is the most important branch of the maxillary artery. The middle meningeal artery arises from the first part of the maxillary artery. It ascends upwards deep to the lateral pterygoid, behind the mandibular nerve. Passing between the two roots of the auriculotemporal nerve, to enter the cranial cavity through foramen spinosum in company with meningeal branch of mandibular nerve (nervus spinosus). As it emerges in the cranial cavity, it courses laterally on the floor of the middle cranial fossa and turns upwards and forwards on the greater wing of the sphenoid, where it divides into frontal and parietal branches: (a) Frontal (anterior) branch, courses up towards the pterion and then curves backwards to ascend towards the vertex, lying over the precentral gyrus of the cerebral hemisphere. In the region of pterion the artery frequently lies in a bony tunnel in the parietal bone for a centimeter or more. (b) Parietal (posterior) branches arch backwards on the squamous part of the temporal bone, cross the lower border of the parietal bone in front of its mastoid angle; here it divides into branches, which spread out as far as lambda. It lies along the superior temporal gyrus. Distribution: The middle meningeal artery and its branches lie outside the dura and deep to the inner surface of the skull. Both of these are supplied by the artery. N.B. The middle meningeal artery and its branches are accompanied by corresponding veins, which lie between the artery and the bone. Inferior alveolar/dental artery —runs downwards between the sphenomandibular ligament and the ramus of the mandible, enters the mandibular foramen, runs through the mandibular canal, supplies molar and premolar teeth and adjoining gum. It then divides into mental and incisive branches. The incisive branch supplies the canine and incisor teeth. The mental artery emerges through the mental foramen to supply the skin of the chin. Before entering the mandibular foramen the inferior alveolar artery gives off two branches, namely, a) Lingual branch: accompanies the lingual nerve and supply the mucous membrane of the cheek. (b) Mylohyoid branch: pierces the lower end of the sphenomandibular ligament, passes downwards and forwards to run in the mylohyoid groove. It supplies the mylohyoid muscle. Branches from the Second Part (Four Branches) 1. Deep temporal arteries (usually two in number)— ascend up on the lateral aspect of the skull deep to the temporalis muscle, which they supply. 2. Pterygoid branches—supply the medial and lateral pterygoid muscles. 3. Masseteric artery—passes laterally through the mandibular notch and supplies the masseter muscle from its deep surface. 4. Buccal artery—supplies buccinator muscle.
FCPS, MS,DDS Admission Preparation Program in Dentistry Farmgate 01638885050 Website: www.purebasic.com.bd 3 | P a g e Branches from the Third Part (Six Branches) 1. Posterior superior alveolar artery arises from maxillary artery just before it enters the pterygomaxillary fissure. It divides into two or three branches, which enter the foramina on the posterior surface of the body of maxilla, runs into alveolar canals and supply the molar and premolar teeth and mucus membrane of maxillary air sinus. 2. Infraorbital artery also arises from maxillary artery just before it reaches the pterygopalatine fossa. The artery passes successively through inferior orbital fissure, infraorbital groove, and infraorbital canal, and appears on the face through the infraorbital foramen. It gives the following branches: In the orbit: (a) Branchestoorbitalcontents. (b) Middle superior alveolar artery to premolar teeth. (c) Anterior superior alveolar artery, which descends through canaliculus sinuosus in the anterior wall of the maxillary sinus. It supplies the maxillary air sinus, and canine and incisor teeth of the upper jaw. In the face, It gives off branches to supply the lacrimal sac, medial angle of the eye, side of nose, and upper lip. 2. Greater palatine artery passes downwards in the greater palatine canal and appears in the oral cavity at the posterolateral corner of the hard palate through the greater palatine foramen. Now it runs forwards in the groove along the alveolar arch to the incisive fossa where it enters the lateral incisive canal to enter the nasal cavity. It supplies the roof of the mouth and adjoining gum, while in the greater palatine canal the artery gives off lesser palatine arteries that emerge through foramina of the same name and supply the soft palate and tonsil. 3. Sphenopalatine artery is considered as the continuation of the maxillary artery. It is the most important branch of the third part of the maxillary artery. It enters the nasal cavity in the posterior part of the superior meatus through sphenopalatine foramen. Here it divides into: (a) posteriorlateralnasal,and (b) posterior septal branches. The posterior lateral nasal branches supply the lateral wall of the nose and sphenoidal and ethmoidal air sinuses, the posterior septal branches cross the undersurface of the body of the sphenoid, and then pass forwards and downwards along the nasal septum. One of the branches of this group is long, runs in a groove on the vomer towards the incisive canal and anastomoses with the terminal branch of the greater palatine artery.
FCPS, MS,DDS Admission Preparation Program in Dentistry Farmgate 01638885050 Website: www.purebasic.com.bd 4 | P a g e Maxillary Vein It is a short venous trunk, which accompanies the first part of the maxillary artery. It is formed by the confluence of veins from the pterygoid venous plexus and passes backwards between the sphenomandibular ligament and the neck of the mandible. Within the parotid gland it unites with the superficial temporal vein to form the retromandibular vein. Pterygoid Venous Plexus It is a network of very small veins that lie around and within the lateral pterygoid muscle. The pterygoid venous plexus communicates: (a) withinferiorophthalmicveinviainferiororbitalfissure, (b) with cavernous sinus by emissary veins via foramen ovale or foramen of Vesalius, and (c) with facial vein through the deep facial vein. The plexus is drained by maxillary vein which is formed at the lower border of the lateral pterygoid muscle. N.B. The pterygoid venous plexus is sometimes referred to as a peripheral heart for during yawning when the mouth is widely open due to contraction of lateral pterygoid muscle, the stagnant venous blood is pumped up into the cavernous sinus and maxillary vein. Possibly this is the reason why people yawn in the morning when they get up from sleep. MAXILLARY NERVE The maxillary nerve, the second division (V2) of the trigeminal nerve is purely sensory. Course and Relations It arises from the convex anterior border of the trigeminal ganglion, pierces the trigeminal cave of dura to reach the lower part of the lateral wall of the cavernous sinus. The nerve leaves the middle cranial fossa through foramen rotundum to reach the pterygopalatine fossa. It traverses straight in the upper part of the fossa and enters the orbit through inferior orbital fissure, hence it is called infraorbital nerve. The infraorbital nerve (in fact a continuation of maxillary nerve) runs forward along the floor of the orbit in the infraorbital groove and canal in succession and appears on the face, through infraorbital foramen. Therefore in its course the maxillary nerve traverses four regions in succession: the middle cranial fossa, the pterygopalatine fossa, the orbit and the face. N.B. In the pterygopalatine fossa the pterygopalatine ganglion is suspended from the maxillary nerve by two roots.