Temporal and Infra Temporal Fossa | Human Face | Skeletal System | Biology

In this article we will discuss about the temporal and infra temporal fossa of human face.

Temporal Fossa of the Human Face:

Boundaries:

It is bounded:

Anteriorly – Zygomatic process of frontal bone and frontal process of zygomatic bone.

Posteriorly – Temporal line.

Superiorly – Superior temporal line.

Inferiorly – Zygomatic arch.

Floor – Parts of – frontal, parietal, temporal and greater wing of sphenoid bone.

Contents:

1. Temporalis muscle and fascia.

2. Deep temporal nerves – two

3. Deep temporal vessels – two

4. Auriculo – temporal nerve

5. Superficial temporal vessels.

Infra Temporal Fossa of the Human Face:

Situation:

It is situated below the zygomatic arch and temporal fossa, in the deeper aspect of the lateral surface of the face.

Boundaries of Infra Temporal Fossa:

Anterior:

Posterior surface of maxilla

Posterior:

1. Styloid process

2. Tympanic plate of temporal bone

3. Carotid sheath

Medial:

Lateral pterygoid plate.

Superiorly:

1. Infra temporal surface of greater wing of sphenoid bone.

2. Squamous part of temporal bone.

Inferiorly:

This fossa is continuous with para-pharyngeal spaces.

Lateraly:

Inner surface of ramus of mandible.

Communications:

Anteriorly- With orbit through inferior orbital fissure.

Medially- With pterygo palatine fossa through pterygo maxillary fissure.

Superiorly- With temporal fossa deep to zygomatic arch, and middle cranial fossa via foramen ovale, foramen spinosum and foramen lacerum.

Inferiorly- With para pharyngeal spaces.

Contents:

1. Mandibular nerve and its branches.

2. Maxillary artery and its branches.

3. Chorda tympani nerve.

4. Otic ganglion.

Applied Anatomy of Infra Temporal Fossa:

1. Head of mandible may dislocate forwards into the infra temporal fossa and compresses the structures present in it, e.g., mandibular nerve, maxillary artery etc.

2. Any growth from maxillary air sinus may grow posteriorly and involve the contents of infra temporal fossa.

3. Infection from dangerous area of face spread to cavernous sinus through pterygoid venous plexus communicates through emissary veins.

4. Collection of pus or blood in the infra temporal fossa may pass downwards to para pharyngeal spaces.

Muscles of Mastication:

Mastication is a process by which food is made into small particles. This function is done by muscles of mastication and temporo mandibular joint.

Muscles involved are:

i. Masseter

ii. Temporalis

iii. Medial pterygoid and

iv. Lateral pterygoid.

Development:

The muscles of mastication are developed from mesoderm of first pharyngeal arch. The nerve of this arch is mandibular nerve – supplies all the muscles of mastication (V₃).

I. Masseter Muscle:

Gr = Masseter = a Chewer

Origin:

Anterior 2/3 of zygomatic arch by tendinous fibres.

Entire medial surface of arch by fleshy fibres.

Insertion:

i. Outer surface of ramus and

ii. Angle of mandible

Relations:

Deep:

Buccal pad of fat

Masseteric nerve and vessels

Buccal branch of anterior division of mandibular nerve.

Superficial:

Transverse facial artery and vein

Parotid duct and gland

Branches of facial nerve.

Nerve Supply:

Masseteric nerve branch of mandibular nerve.

Action:

Elevation of mandible. It locks the jaw and clinches the teeth.

Applied Anatomy:

1. In Tetanus – Spasm of this muscle causes lock jaw or trismus.

2. Facial artery crosses lower border of mandible at antero inferior angle of masseter muscle. Pulsations of artery can be felt here.

II. Temporalis Muscle:

It is fan shaped muscle present in temporal fossa.

Origin of temporalis from:

i. Floor of temporal fossa and

ii. Temporal fascia.

Insertion:

Margins and deep surface of coronoid process and anterior border of Ramus of mandible.

Nerve:

Two deep temporal nerve branch of anterior division of mandibular nerve.

Action:

Anterior and superior fibres elevate the mandible.

Posterior Fibres:

Retract the protruded mandible.

III. Lateral Pterygoid:

Arises by two heads – upper and lower.

Origin:

A. Upper Head (Small):

Infra temporal surface and crest of greater wing of sphenoid bone.

B. Lower Head (Large):

Lateral surface of lateral pterygoid plate.

Insertion:

Fibres run backwards laterally converge and inserted on pterygoid fovea present on anterior surface of neck of mandible.

Anterior margin of articular disc and capsule of temporo mandibular joint.

Nerve Supply:

Pterygoid branch of anterior division of mandibular nerve.

Action:

It depresses the mandible to open mouth.

Lateral pterygoid of one side and medial pterygoid of other side – protrudes the mandible and causes side to side movement as in chewing, when act alternatively.

Relations:

A. Superficial:

i. Masseter

ii. Ramus of mandible

iii. Tendon of temporalis

iv. Maxillary artery.

B. Deep:

i. Mandibular nerve

ii. Middle meningeal artery

iii. Sphenomandibular ligament

iv. Deep head of medial pterygoid muscle.

C. Structures emerging at upper border of lateral – pterygoid – deep temporal nerves and masse­teric nerve.

D. Structures emerging at lower border of lateral – pterygoid.

Lingual nerve.

Inferior alveolar nerve.

Middle meningeal artery passes upwards deep to it.

E. Structures passing through gap between two heads of lateral pterygoid –

Maxillary artery enters the gap.

Buccal branch of mandibular nerve comes out through gap.

F. Pterygoid venous plexus – surrounds lateral – pterygoid muscle.

IV. Medial Pterygoid:

Origin by two heads:

A. Superficial Head (Small Slip):

Tuberosity of maxilla and adjoining bone.

B. Deep Head:

Medial surface of lateral pterygoid plate and adjoining part of palatine bone (Pyramidal process).

Insertion:

Fibres run downwards, backwards and laterally to insert on medial surface of angle and ramus of mandible.

Nerve Supply:

To medial pterygoid from main trunk of mandibular nerve a branch arises and supplies it.

Applied Anatomy of Infra Temporal Fossa:

1. Head of mandible may dislocate forwards into infra temporal fossa and compresses the structures like mandibular nerve and maxillary artery.

2. Any growth from maxillary air sinus may grow posteriorly and invade the contents of infra temporal fossa.

3. Infection from dangerous area of face spread into facial vein → deep facial vein → pterygoid venous plexus → emissary vein → cavernous sinus → may lead to meningitis or encephalitis.

4. Collection of fluid – pus or blood in infra temporal fossa may pass downwards to para pharyngeal space.

Location or Situation of Infra Temporal Fossa:

Infratemporal fossa just below foramen ovale, medial to mandibular nerve and lateral to tensor palati surrounds origin of medial pterygoid nerve.

Relations:

Anterior- Medial pterygoid muscle

Posterior- Middle meningeal artery

Lateral- Trunk of mandibular nerve

Medial- Tensor veli palatini.

1. Mandibular Nerve:

This is the largest of the three divisions of the trigeminal nerve.

It is the nerve of the first branchial arch.

It is a mixed nerve – consists of both sensory and motor fibres.

Origin:

It is formed by two roots:

(a) Larger Sensory Root:

Arises from the convex aspect of the trigeminal ganglion.

(b) Small Motor Root:

Arises from ventral aspect of pons and passes below the trigeminal ganglion.

Course:

Both roots pass through the foramen ovale and join to form the main trunk, which lies in the infra temporal fossa. After a short course the main trunk divides into a small anterior and a large posterior division.

Relations of the Mandibular Trunk:

Medial – tensor veli palatini

Lateral – lateral pterygoid muscle

Anterior – otic ganglion and tensor palati

Posterior – middle meningeal artery.

Branches:

I. Main Trunk:

(a) Nervous Spinosus or Meningeal Branch:

Enters through foramen spinosum and supplies duramater of middle cranial fossa.

(b) Nerve to Medial Pterygoid:

It supplies medial pterygoid and then passes through otic ganglion and divides into two branches to supply tensor palati and tensor tympani. It forms the motor root of the otic ganglion.

II. Anterior Division:

It consists major part of motor fibres and few sensory fibres.

Motor Branches:

i. Two deep temporal nerves to supply temporalis muscle from its deep surface.

ii. Nerve to lateral pterygoid supplies lateral pterygoid muscle.

iii. Masseteric nerve passes through mandibular notch and supplies masseteric muscle on its deep surface. It also gives a branch to temporo­mandibular joint to supply it.

Sensory Branch:

Buccal nerve supplies skin and mucous membrane of cheek, passes between two heads of lateral pterygoid muscle – downwards and forwards pierces the buccinator muscle to reach its area of distribution, but it does not supply buccinator muscle.

III. Posterior Division:

It consists of major sensory part with few motor fibres, gives rise to three branches:

A. Auriculo Temporal Nerve:

Arises by two roots and consists only sensory fibres. Two roots unite to form single trunk after encircling the middle meningeal artery.

It runs backwards passing behind the insertion of lateral pterygoid muscle, around the neck of the mandible to reach the lateral side behind the temporo mandibular joint, superior to the parotid gland.

It gives:

(a) Auricular Branch:

To supply pinna, external acoustic meatus and adjoining part of tympanic membrane.

(b) Articular Branch:

To temporo mandibular joint.

(c) Superficial Temporal Branches:

To supply area of skin over temple.

(d) Communicating Branches:

It receives post ganglionic secretomotor fibres from otic ganglion to supply parotid gland. It also gives sensory fibres to parotid gland for its sensory supply.

B. Inferior Alveolar Nerve:

It is the larger terminal branch of posterior division of mandibular nerve containing more sensory fibres and few motor fibres means – it is a mixed nerve.

It emerges below the lateral pterygoid and runs over the ramus of mandible to enter the mandibular foramen along with inferior alveolar vessels.

It traverses the mandibular canal and divides into terminal branches:

(a) Nerve to Mylohyoid:

This branch is given before the inferior alveolar nerve enters the mandibular foramen. It consists all its motor fibres to supply mylohoid and anterior belly of digastric muscle and runs into mylohoid groove for its supply.

(b) Dental Branches:

To supply teeth of lower jaw – these branches form inferior dental plexus before supplying the teeth – molar, premolar teeth and adjoining gum of lower jaw.

(c) Mental Nerve:

Passes through mental foramen and supplies skin of chin and lower lip.

(d) Incisive Branch:

Runs forwards into incisive canal of mandible and supplies canine an incisor teeth with the adjoining gum of lower jaw.

(e) Communicating branch to lingual nerve.

C. Lingual Nerve:

It is the smaller terminal branch of posterior division of mandibular nerve. About 2 cm below the base of the skull chorda tympani nerve joins it posteriorly at an acute angle in the infra temporal fossa.

Lingual nerve emerges below the lower border of lateral pterygoid muscle and runs downwards and forwards between the ramus of mandible and medial pterygoid.

It comes in direct contact with mandible medial to the last molar teeth. Here it is covered by mucous membrane of gum only.

Then it crosses styloglossus and hyoglossus laterally.

The submandibular ganglion is suspended from lingual nerve by two roots on the surface of hyoglossus.

Finally it curves under the submandibular duct at the level of genioglossus and turns up medially to the anterior part of tongue and floor of oral cavity.

Branches of Lingual Nerve:

(a) Sensory branches to mucous membrane of anterior 2/3 of tongue, floor of mouth and adjoining area of gum.

(b) Communicating branches with:

i. Chorda Tympani:

The lingual nerve receives secretomotor fibres for submandibular and sublingual glands. It also conveys fibres for taste sensation from anterior 2/3 of tongue to the chorda tympani.

ii. With Hypoglossal Nerve:

Lingual nerve transmits proprioceptive sensations from the lingual muscles via its communicating branches to the hypoglossal nerve.

2. Maxillary artery (Syn. Internal Maxillary artery or mandibulo – maxillary artery)

This artery supplies the structures present on a deeper plane and supplied by branches of mandibular and maxillary nerve.

It is the larger terminal branch of external carotid artery.

Course:

It begins behind the neck of mandible and runs forwards, medially and upward upto the lower border of lower head of lateral pterygoid.

Crosses the lower head superficially sometimes deep and emerges between two heads of lateral pterygoid and enters the pterygo palatine fossa by passing through the pterygomaxillary fissure.

Here it ends by giving its terminal branches.

Parts:

Maxillary artery is divided into three parts by the lower head of lateral pterygoid muscle.

(a) First Part or Mandibular Part:

From its origin to the lower border of lateral pterygoid. It lies between the neck of the mandible laterally and the sphenomandibular ligament medially. Auriculo temporal nerve lies above this part. This part is horizontally placed.

(b) Second Part or Pterygoid Part:

From the lower border of lateral pterygoid to the upper border of lower head of lateral pterygoid muscle.

(c) Third Part or Pterygopalatine Part:

From upper border of lower head of lateral pterygoid to pterygo palatine fossa, where it lies infront of pterygo palatine ganglion.

Branches of Maxillary Artery:

From First Part:

1. Deep auricular artery

2. Anterior tympanic artery

3. Middle meningeal artery

4. Accessory middle meningeal artery

5. Inferior alveolar or dental artery.

From Second Part:

Gives muscular branches and buccal branch.

1. Two deep temporal artery (anterior and posterior).

2. Pterygoid branches – for pterygoid muscles.

3. Masseteric artery – for masseter muscle and T.MJ.

4. Buccal artery – for skin and mucous membrane of cheek.

From Third Part:

1. Posterior superior alveolar artery

2. Infra orbital artery

3. Greater palatine artery

4. Pharyngeal artery

5. Spheno-palatine artery

6. Artery of pterygoid canal occasionally.

Characteristics of Branches:

Branches from 1st and 2nd parts accompany branches of mandibular nerve.

Branches from 3rd part accompany branches of maxillary nerve and pterygo palatine ganglion.

Branches of 1st and 3rd part of maxillary artery enter through a bony canal or foramen to supply their area of distribution.

Middle Meiningeal Artery:

Largest branch from 1st part and most important passes through foramen spinosum and enters middle cranial fossa to supply periosteal dura of the cranial cavity. It ascends upwards deep to lateral pterygoid muscle and behind the mandibular nerve, passes between the two roots of auriculotemporal nerve and enters foramen spinosum along with nervous spinosus branch of mandibular nerve.

Inferior Alveolar Artery:

Passes downwards and enters mandibular foramen to pass into mandibular canal to supply mandible, teeth of the lower jaw and passes through mental foramen to supply skin and mucous membrane of chin and lower lip. It also gives lingual branches to posterior part of the tongue.

Applied Anatomy:

Angle of mandible has poor blood supply and is the site for alveolar osteitis after extraction of lower 3rd molar (wisdom tooth).

Deep Auricular Artery:

Supply external auditory meatus. It passes through squamotympanic fissure.

Anterior Tympanic Artery:

Accompanies chorda tympani nerve through petrotympanic fissure and reaches middle ear to supply.

Accessory Meningeal Artery:

Passes through foramen – ovale to enter middle cranial fossa to supply trigeminal ganglion and surrounding dura.

3. Chorda Tympani Nerve:

It is pre trematic branch of facial nerve.

Carries taste fibres from anterior 2/3 of tongue and parasympathetic fibres to submandibular and sublingual salivary glands.

Commencement and Course:

It arises in the facial canal about 6 mm above the stylomastoid foramen from the facial nerve and enters the middle ear through posterior canaliculus. Passes forwards across the inner surface of tympanic membrane internal to the handle of malleus and then leaves the middle ear by passing through the petrotympanic fissure to appear at the base of skull.

Here it runs downwards and forwards medial to spine of sphenoid and lies deep to:

(i) Lateral pterygoid

(ii) Middle meningeal artery

(iii) Auriculo temporal and

(iv) Inferior alveolar nerve.

Terminates:

By joining the posterior aspect of lingual nerve at an acute angle and distributed with the branches of lingual nerve to anterior 2/3 of tongue, submandibular, sublingual and anterior lingual glands.

4. Otic Ganglion:

It is a peripheral parasympathetic ganglion.

Topographically:

Connected to the mandibular nerve, provides a relay station to secretomotor fibres for the parotid gland.

Functionally:

It is associated with glossopharyngeal nerve.

Size – Pin head – 2-3 mm.

Shape – Oval.

Roots or Connections:

1. Parasympathetic Root:

Pre ganglionic parasympathetic fibres arise from inferior salivatory nucleus and pass via tympanic branch of glossopharyngeal nerve (IXth C.N.) and joins tympanic plexus of nerves in the middle ear. From plexus – lesser superficial petrosal nerve arises and passes through foramen ovale and these fibres are relayed into otic ganglion.

2. Sympathetic Root:

Derived from the sympathetic plexus around middle meningeal artery and conveys postganglionic fibres from superior cervical – sympathetic ganglion. These fibres do not relay in the otic ganglion.

3. Motor Root:

Nerve to medial pterygoid pass through the ganglion without relay.

4. Sensory Root:

Auriculo temporal nerve passes without relay.

Branches and Distribution:

1. Nerve to tensor tympani.

2. Nerve to tensor palati.

3. Communicating branches to auriculotemporal nerve, these convey post ganglionic parasym­pathetic fibres which are secretomotor to parotid gland and sympathetic fibres are vasomotor for parotid, fibres of auriculo temporal are sensory for the gland.

4. Communicating branches to chorda tympani.

5. Communicate with nerve to pterygoid canal.