Mandibular Nerve
The largest division of the trigeminal nerve (CN V) and the only one with a motor root. Exits through foramen ovale into the infratemporal fossa, dividing into anterior (predominantly motor) and posterior (predominantly sensory) divisions.
Overview and Origin of Mandibular Nerve
General Character
- Mandibular nerve (V3) is the largest of the three divisions of the trigeminal nerve (CN V)
- It is the only division with a motor root — it carries both sensory and motor fibres
- Classified as a mixed nerve (sensory + motor)
Roots
Root Origin Character Large sensory root From lateral part of trigeminal (semilunar/Gasserian) ganglion General somatic afferent Small motor root Bypasses the ganglion, runs medial to sensory root Special visceral efferent
- Both roots exit the skull through foramen ovale in the greater wing of sphenoid
- They unite just below the foramen ovale in the infratemporal fossa to form the main trunk
Main Trunk (Undivided Segment)
The two roots unite to form a short undivided trunk (~2–3 mm) which immediately gives off:
Branch Type Distribution Meningeal branch (nervus spinosus) Sensory Re-enters skull through foramen spinosum with middle meningeal artery; supplies dura mater of middle cranial fossa and mastoid air cells Nerve to medial pterygoid Motor Supplies medial pterygoid; also gives branches to tensor tympani and tensor veli palatini Division
The main trunk then divides into:
Division Character Branches Anterior division (smaller) Predominantly motor 3 motor + 1 sensory (buccal) Posterior division (larger) Predominantly sensory 3 sensory branches + motor to mylohyoid Mnemonic (Trigeminal branches): “O My Mamma” — Ophthalmic (V1), Maxillary (V2), Mandibular (V3)
Relations at Foramen Ovale
The nerve lies in the infratemporal fossa, medial to the lateral pterygoid, lateral to the tensor veli palatini, with the otic ganglion suspended from its medial aspect.
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Sensory Distribution of Mandibular Nerve
Overview
The mandibular nerve (V3) provides general somatic afferent (sensory) supply to the following regions. It does not supply the cornea, nasal cavity, or upper face (those are V1 and V2).
Cutaneous (Skin) Distribution
Nerve Skin Area Auriculotemporal nerve Temple (anterior temporal region), tragus of ear, upper part of auricle, skin of external acoustic meatus, outer surface of tympanic membrane Buccal nerve (long buccal) Skin and mucous membrane of cheek Mental nerve (terminal branch of inferior alveolar) Skin of chin, lower lip, mucous membrane of lower lip Inferior alveolar nerve Gingiva and skin over lower jaw (before terminating as mental nerve) Mucous Membrane Distribution
Nerve Mucosal Area Lingual nerve Anterior 2/3 of tongue (general sensation — touch, pain, temperature); floor of mouth; lingual gingiva of lower teeth Buccal nerve Mucous membrane of cheek; buccal gingiva of lower molar teeth Inferior alveolar nerve Gingiva of lower teeth; inner aspect of lower lip (via mental nerve) Teeth and Bone
Nerve Structures Inferior alveolar nerve (via inferior dental plexus) All lower teeth (incisors, canines, premolars, molars) on the same side Mental nerve Premolars, canines, incisors (by communicating branches) Special Sensory — Taste
V3 itself carries no taste fibres. Taste from anterior 2/3 tongue is carried by chorda tympani (branch of CN VII) which joins the lingual nerve — these are VII fibres travelling in the V3 sheath.
Joint
- Temporomandibular joint (TMJ): Supplied by auriculotemporal nerve (posterior aspect) and masseteric nerve (anterior aspect)
Summary Map
Link to originalTemple / scalp (anterior) ← Auriculotemporal nerve Auricle (tragus, upper part) ← Auriculotemporal nerve External acoustic meatus ← Auriculotemporal nerve Cheek (skin + mucosa) ← Buccal nerve Chin + lower lip (skin) ← Mental nerve Floor of mouth ← Lingual nerve Tongue anterior 2/3 (general) ← Lingual nerve Lower teeth (all) ← Inferior alveolar nerve Lingual gingiva (lower) ← Lingual nerve Buccal gingiva (lower molars) ← Buccal nerve
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