Temporal and Infratemporal Regions Questions and Answers

Temporal and Infratemporal Regions Questions and Answers

Question 1: Give the branches of 1st part of the maxillary artery.

Answer: DAIMA

1. Deep auricular,
2. Anterior tympanic,
3. Inferior alveolar,
4. Middle meningeal, and
5. Accessory meningeal.

Body Fluids	Muscle Physiology	Digestive System
Endocrinology	Face Anatomy	Neck Anatomy
Lower Limb	Upper Limb	Nervous System

Read And Learn More: Head Anatomy Notes And Important Questions With Answers

Maxillary artery

Maxillary artery Introduction: It is one of the two terminal branches of the external carotid artery given at the neck of the mandible. It is the artery of the upper and lower jaws, the muscles of mastication, the palate, and the nose.

1. Maxillary artery Course: It is divided into three parts by the lower head of the lateral pterygoid muscle.
It enters the infratemporal fossa.
It lies between the neck of the mandible and the sphenomandibular ligament.
Here the auriculotemporal nerve is above the artery and the maxillary vein lies below the artery.
It enters the pterygopalatine fossa through the pterygomaxillary fissure.
It is divided conveniently into three parts by lateral pterygoid muscle

1. 1st part lies proximal to the lower head of the lateral pterygoid.
2. 2nd part lies in relation to the lateral pterygoid.
   It lies either superficial or deep to the lower head of the lateral pterygoid.
3. 3rd part lies in the pterygopalatine fossa distal to the upper head of the lateral pterygoid.

2. Maxillary artery Branches: Branches of 1 stand 2nd parts accompany the branches of the maxillary nerve.

3. Maxillary artery Applied anatomy

1. Middle meningeal artery is the largest meningeal branch. Clinically, it is the most a important branch of maxillary artery.
2. It may be torn in fracture of the skull producing extradural haematoma that –
   overlies the motor area of the cerebral cortex.

Question 2: Describe Infratemporal Fossa under the following heads:
1. Infratemporal Fossa  Boundaries,
2. Infratemporal Fossa  Contents, and
3. Infratemporal Fossa  Applied anatomy

Answer: 1. Infratemporal Fossa  Boundaries

Infratemporal Fossa  Location: It is the space located deep to the ramus of the mandible.

Infratemporal Fossa  Communication

1. Temporal fossa.
2. Orbit.
3. Middle cranial fossa

Infratemporal Fossa  Openings

1. Foramen ovale,
2. Foramen spinosum,
3. Pterygomaxillary fissure, and
4. Inferior orbital fissure.

Note: The foramen rotundum cannt be seen in the roof of infratemporal fossa.

Infratemporal Fossa  Superiorly or roof: It is formed by

1. The inferior surface of the greater wing of the sphenoid bone.
2. Mandibular surface and inferior surface of the petrous part of the temporal bone.

Infratemporal Fossa  Anteriorly

1. Posterior surface of maxilla.
2. Inferior orbital fissure.

Infratemporal Fossa  Medially

1. The lateral surface of the lateral pterygoid plate.
2. Tensor palatini.
3. Superior constrictor.
4. Pterygomaxillary fissure.

Infratemporal Fossa  Posteriorly

1. The anterior surface of the styloid process of the temporal bone.
2. Carotid sheath.

Infratemporal Fossa  Laterally

1. Medial surface of the ramus of the mandible.
2. Coronoid process.

2. Infratemporal Fossa  Contents

A deep part of the parotid gland

Infratemporal Fossa  Muscles

1. Insertion of temporal is into the coronoid process,
2. Medial pterygoid, and
3. Lateral pterygoid.

Infratemporal Fossa  Arteries: The Maxillary artery and its branches from the 1st and 2nd parts are the contents of the infratemporal fossa.

Branches of 1st part

1. Deep auricular,
2. Anterior tympanic,
3. Inferior alveolar,
4. Middle meningeal, and
5. Accessory meningeal.

Branches of 2nd part (to muscles of mastication).

1. Masseteric branch,
2. Temporal branch,
3. Pterygoid branch, and
4. Buccal branch.

Pterygoid Venous Plexus
Nerves

Branches of mandibular division of trigeminal nerve.

Branches from the main trunk.

1. Branch to medial pterygoid.
2. Meningeal branch.

Branches from the anterior trunk (mainly motor)

1. Masseteric branch.
2. Branch to lateral pterygoid.
3. Deep temporal branch.
4. Buccal branch.

Sensory branches are not the contents of the infratemporal fossa.

Chorda tympani nerve

Posterior superior alveolar branches of maxillary nerve.

Ganglion: Otic ganglion.

Applied anatomy

1. Lefort and zygomatic fracture: It is a bilateral horizontal fracture of the maxilla.
   It invariably involves infratemporal fossa.
   It damages the nerves, blood vessels, and muscles in the region.
   The clinical manifestations are Injuries to the 2nd and 3rd divisions of the trigeminal nerve and chorda tympani resulting in altered sensations in the oral cavity and face.
   Injuries involving otic ganglion interfere with salivation.
   Damage to the motor nerve results in loss of chewing and swallowing movements.
2. Fractures of the zygomatic bone involve the infratemporal fossa and the maxillary
   air sinus.
   The infection of this region has grave consequences.
   It spreads in the middle cranial fossa through the various foramina present at the roof of the fossa.
3. Infection from
   The impacted 3rd molar tooth also spreads to the infratemporal fossa.
   The main symptom of the infection is painful reflex muscle spasm.
   The infratemporal fossa may spread to orbit through inferior orbital fissures.
   It may result in cavernous sinus thrombosis.
4. Infection also can spread to the nose, palate, and pharynx through the pterygopalatine fissure.

Question 4:  Describe muscles of mastication under the following headings:
1. Muscles Of Mastication Proximal attachments,
2. Muscles Of Mastication Distal attachments,
3. Muscles Of Mastication Action, and
4. Muscles Of Mastication Nerve supply

Answer:

4. Muscles Of Mastication Nerve supply: All the muscles of mastication are supplied by branches from the anterior trunk of the mandibular nerve except the medial pterygoid which is supplied by the branch from the main trunk of the mandibular nerve.

Pterygoid venous plexus

Introduction: It is a plexus of veins present

1. Superficial to lateral pterygoid muscle.
2. Deep to lateral pterygoid muscle.
3. In the lateral pterygoid muscle.
4. Partly between temporalis and lateral pterygoid.
5. Partly between two pterygoid muscles.

1. Tributaries of the plexus correspond to the branches of the maxillary arteries. They are

1. From muscles of mastication.

1. Deep temporal
2. Masseter
3. Pterygoid
4. Buccal

2. Veins of palate

1. Palatine
2. Sphenopalatine

3. Veins of cranium: Middle meningeal vein

2. Termination: It drains into the maxillary vein which is formed at the lower border of
lateral pterygoid muscle deep to the neck of the mandible.
They run back and join with the superficial temporal vein to form the retromandibular vein.
3. Communications: It has important communication with

1. Inferior ophthalmic vein through veins of the inferior orbital fissure.
2. Cavernous sinus via emissary veins. These emissary veins pass through the foramen ovale and foramen of Vesalius (emissary sphenoidal foramen)
3. Facial vein via deep facial veins.

4. Role of pterygoid plexus: (Contraction of lateral pterygoid muscle facilitates venous return to the heart. Hence, lateral pterygoid is called a peripheral heart.) The veins of the plexus have valves that suck the blood from incompressible parts (face, bones, and orbit) and pump it back into maxillary veins.

5. Applied anatomy: The infection from the face can spread to the cavernous sinus via the plexus.

Lateral Pterygoid Muscle

Lateral Pterygoid Muscle Introduction: It is the muscle of mastication.

1. Lateral Pterygoid Muscle Features:
1. It acts as a peripheral heart. It has a plexus of veins present

1. Superficial to lateral pterygoid
2. In the lateral pterygoid
3. Deep to lateral pterygoid
   These veins have valves that help in venous return.

2. The emissary veins passing through the foramen ovale and foramen lacerum connect the pterygoid venous plexus to the cavernous venous sinus.

3. It is a key muscle of the temporal and infratemporal regions.

2. Lateral Pterygoid Muscle Origin: It arises from two heads

1. Upper head arises from

1. Roof of infratemporal fossa.
2. Infratemporal crests of the greater wing of the sphenoid bone.

2. The lower head is larger and arises from the lateral surface of the lateral pterygoid plate.

3. Lateral Pterygoid Muscle Insertion: The two heads lying edge-to-edge fuse and form a short tendon which is inserted into

1. Pterygoid fovea of the neck of the mandible.
2. Capsule of temporomandibular joint.
3. Articular disc of temporomandibular joint.

4. Lateral Pterygoid Muscle Relations

1. Superficial (visualize mandible and structures attached and related to it.)

1. Masseter,
2. Ramus of the mandible,
3. Tendon of temporalis, and
4. Maxillary artery.

2. Deep

1. Mandibular nerve
2. Middle meningeal artery
3. Sphenomandibular ligament
4. Deep head of medial pterygoid

3. Structures emerging at the upper border

1. Deep temporal nerve
2. Masseteric nerve

4. Structures emerging at the lower border

1. Lingual nerve,
2. Inferior alveolar nerve, and
3. Middle meningeal artery.

5. Between two heads of lateral pterygoid

1. 3rd part of the maxillary artery.
2. Buccal branch of mandibular nerve.

5. Lateral Pterygoid Muscle Nerve supply: It is supplied by a branch anterior division of the mandibular nerve.
6. Action

1. It is an indispensable muscle for the active opening of the mouth.NEEr
2. Protraction: It draws condyle and disc forward.
3. Helps in side-to-side movements.

7. Development: It is developed from the mesoderm of 1st pharyngeal arch.

Question 5: Describe the mandibular nerve under the following headings:
1. Course and relations,
2. Development,
3. Branches, and
4. Applied anatomy

Introduction: It is 3rd division of the trigeminal nerve. It is a mixed nerve supplying the muscles developed from 1st pharyngeal arch. It is also sensory to the skin and mucous membrane of the mandible.

1. Course and relations

1. It arises from trigeminal ganglion.
2. It lies in the dura mater of the middle cranial fossa lateral to the cavernous sinus.
3. The sensory and motor roots pass through the foramen ovale.
4. Both roots meet in the infratemporal fossa and a mixed nerve is formed.
5. It begins as a trunk and divides into anterior and posterior divisions.
6. The nerve lies deep to the upper head of the lateral pterygoid and tensor palatini.
7. The optic ganglion lies between the mandibular nerve and the lateral pterygoid.

2. Development: It is the nerve of the 1st pharyngeal arch.

3. Branches

From main trunk

Sensory: Meningeal (nervus spinosus): It gives a cartilaginous branch to the eustachian tube and enters the middle cranial fossa through foramen spinosum.
It is accompanied by middle meningeal vessels. In the skull, it supplies

1. Dura mater of middle cranial fossa,
2. Mastoid antrum, and
3. Mastoid air cells.

Motor: It gives the motor branch to the medial pterygoid and gives the motor root to the otic ganglion.
The root passes near or through the ganglion without synapse.
Its fibres supply

1. Tensor palatini, and
2. Tensor tympani

Branches from divisions: After a distance of 4 to 5 mm, the nerve divides into a cat of nine tails. Six branches from the anterior division and three branches from posterior division.

Anterior division (mainly motor): All the branches of the anterior division are motor except the buccal branch which is sensory.

Masseteric nerve: It runs on the upper border of the lateral pterygoid and supplies

1. Masseter muscle, and
2. Temporomandibular joint.

Buccal branch: It is purely sensory. It passes between two heads of lateral

pterygoid. It runs in a fascial tunnel on the deep surface of the temporal muscle
and supplies

1. The external skin of the cheek,
2. Internal mucous membrane,
3. Proprioceptive sensations of buccinator muscle, and
4. Gums of lower jaw opposite lower molar and premolar.
   Along with parotid duct, buccal branch of mandibular nerve pierces buccinator.

Pterygoid branches: They are two in number and supply

Upper head of lateral pterygoid, and

Lower head of lateral pterygoid.

Temporal branches: They are anterior and posterior and run on the upper border of the lateral pterygoid.

They supply the temporalis muscle.

Posterior division (mainly sensory): All the branches of the posterior division are sensory except the nerve to mylohyoid which is motor.

As a rule, the anterior division is motor, and the posterior division is sensory.
Every rule has an exception.
On a lighter note: Exception proves the rule. If there are no exceptions, there are no rules.
All the branches of the anterior division are motor except the buccal branch which is sensory.
All the branches of the posterior division are sensory except the nerve to the mylohyoid which is motor.

Auriculotemporal: It arises from two roots.

It hugs the middle meningeal artery since it is going to the temple to have a darshan.

It passes backward between the neck and the ligament of the mandible (sphenomandibular ligament).
As the name suggests, it supplies structures surrounding the ear and temporal region.

1. Skin of temporal region,
2. Temporomandibular joint,
3. Tragus,
4. The upper part of the pinna of ear,
5. The outer surface of the tympanic membrane, and
6. Parotid gland (postganglionic secretomotor fibres from otic ganglion).

Great auricular nerve is great in the following aspects

1. It is the largest ascending branch of the cervical plexus.

2. It supplies the skin over the parotid gland and parotid fascia.

3. It supplies the area of skin of the ear which is pinched by a person who is great for the pinched person.
Note: Skin over the parotid gland and parotid fascia is supplied by the great auricular nerve.

2. Inferior alveolar nerve

1. It is a large branch of the posterior division.
2. It emerges below the lower head of the lateral pterygoid.
3. It lies anterior to its vessels and between sphenomandibular ligament 1 and the ramus of the mandible.
4. It gives a branch called a nerve to the mylohyoid and enters the mandibular canal.
5. Nerve to mylohyoid pierces sphenomandibular ligament. It supplies
   Mylohyoid muscle, and
   Anterior belly of digastric muscle.
6. Inferior alveolar nerve supplies
   Three molars and two premolar teeth. It divides into
   Mental nerve, and
   Incisive nerve. It supplies pulps and the periodontal membrane of the canine and incisors.
7. Lingual nerve: It appears below the lateral pterygoid muscle on the side of the pharynx.
   It joins with the chorda tympani at an acute angle.
   It emerges medial to the mandible at the third molar tooth.
   It carries General and special sensations of the anterior two-thirds of the tongue (through chorda tympani)
   The mucous membrane of the floor of the mouth.

4. Applied anatomy

1. The sensory function of the mandibular nerve is tested with a wisp of cotton on the skin of the mandible.
2. Motor function of the mandibular nerve is tested by asking the patient to clench the teeth firmly.
   The contraction of the masseter can be felt by palpation when the teeth are clenched.
3. Injury to trigeminal nerve causes paralysis of muscles of mastication.
   The chin is kept in the midline by the balanced tone of the muscles.
   In paralysis of the pterygoid muscles of one side, the chin is pushed to the paralyzed side by the muscles of the opposite side.
4. Pain arising from an area supplied by one branch of the trigeminal nerve may be referred to as another area of skin supplied by another branch of the nerve.
   Thus, caries of the teeth of the lower jaw or ulcer of the tongue may cause pain in the ear because both are supplied by branches of the mandibular nerve.
   A needle introduced to a depth of 4 cm in the coronal plane above the mandibular notch and in front of the neck of the mandible reaches the mandibular nerve.
   Usually, the needle is inserted until it strikes the lateral pterygoid plate.
   It is then passed posteriorly along the lateral pterygoid plate to reach the vicinity of the foramen ovale.
5. Mandibular nerve block: It is given for the extraction of the teeth of the lower jaw.
   The needle is inserted in the interval between pterygomandibular raphe and the anterior margin of the ramus of the mandible.
   The tip of the needle is near the inferior alveolar nerve, just before it enters the mandibular canal. The anesthetic injected here blocks the nerve.
6. A lesion at the foramen ovale involves the mandibular nerve and results in paraesthesia along the mandible, the lower (mandibular) teeth, and the side of the face. There is also paralysis of muscles of mastication and loss of the jaw-jerk reflex as this nerve supplies both afferent and efferent fibers for the jaw-jerk reflex.
7. Mandibular neuralgia: The pain along the distribution of mandibular division of trigeminal nerve is called mandibular neuralgia. It is often difficult to treat. This is treated by division of the sensory root of the trigeminal nerve.

Inferior alveolar (dental) nerve

Introduction: It is a branch of the mandibular nerve. Its muscular part supplies the mylohyoid and anterior belly of the digastric.
Its sensory part carries sensations of the teeth, pulp, and periodontal membrane of the lower jaw.

1. Origin: It arises from the posterior division of the mandible nerve, below the lower head of the lateral pterygoid.

2. Course and relations: It lies anterior to its vessels between the sphenomandibular ligament and ramus of the mandible and enters the mandibular foramina.
It runs along with vessels in the mandibular canal. It supplies three molars and two premolars.

3. Branches

1. Mental nerve,
2. Incisive nerve and
3. Nerve to mylohyoid: It pierces the sphenomandibular ligament and supplies mylohyoid muscle.

4. Applied anatomy

1. An inferior alveolar nerve block is used for the extraction of all teeth, except incisors.
2. For inferior alveolar block, the needle is inserted orally through the buccinator
   above the 3rd molar tooth and in front of pterygomandibular raphe.

SN-85 Otic ganglion

It is a collection of cell bodies of postganglionic parasympathetic nerves. It is situated t outside the central nervous system. The fibers supply the parotid gland. Topographically ”
(the description of the anatomical region), it is related to the mandibular nerve and functionally it is related to the glossopharyngeal nerve.

1. Size: 2-3 mm in size.

2. Situation: Infratemporal fossa at the base of foramen ovale.

3. Synonym: Arnold ganglion.

4. Relations of otic ganglion

1. Superiorly: Foramen ovale.
2. Anteriorly: Medial meningeal muscle
3. Posteriorly: Middle meningeal artery.
4. Medially: Tensor veli palatini.
5. Latera11y: Mandibular nerve.

5. Connections:

1. Parasympathetic or motor root

1. Preganglionic: Inferior salivatory nucleus-glossopharyngeal nerve—panic branch of glossopharyngeal nerve.
   It forms the tympanic plexus along with caroticotympanic branch of the internal carotid artery. A branch from the plexus, a lesser petrosal branch is given that passes through foramen ovale-otic ganglion-relay.
2. Postganglionic: Auriculotemporal nerve-parotid gland.

2. Sensory: The auriculotemporal nerve passes through the otic ganglion without a relay.

1. 

Sympathetic

1. Preganglionic: Spinal nerve-superior cervical sympathetic ganglion.
2. Postganglionic: Plexus around external carotid artery-maxillary artery middle meningeal artery.

6. Branches:

1. Auriculotemporal nerve to parotid gland.
2. Nerve to the medial pterygoid passes through the otic ganglion and supplies the
   Tensor palatini, and Tensor tympani.
3. The otic ganglion is connected to the chorda tympani nerve and the nerve of the pterygoid canal.
   This communicating channel possibly forms an alternate route of the taste pathway from the anterior two-thirds of the tongue to the geniculate ganglion of the facial nerve.

7. Applied anatomy: Injury to the auriculotemporal nerve manifests in the loss of salivation.