Motor Innervations

CN V: Trigeminal

Involved in mastication and sensation of the face, with the mandibular branch controlling muscles of mastication.

Muscles of Mastication

Include the lateral pterygoid, masseter, and temporalis, primarily controlling jaw movements.

CN VII: Facial Nerve

Responsible for facial expression and taste; branches include temporal, zygomatic, buccal, mandibular, and cervical.

Buccinator

Important muscle for swallowing, provides tone, flattens the cheek, and holds food in contact with the cheek.

UMN Innervation of the Face

Upper face receives bilateral upper motor neuron innervation; lower face receives contralateral innervation.

CN IX: Glossopharyngeal

Innervates the stylopharyngeus muscle and parasympathetically controls the parotid gland.

Stylopharyngeus Muscle

The only motor portion of CN IX, elevates and dilates the pharynx.

Pharyngeal Plexus

Formed by CN IX and CN X, innervating the soft palate and pharyngeal muscles.

CN X: Vagus Nerve

Involved in swallowing and talking, with features including pharyngeal branches and recurrent laryngeal nerve.

Recurrent Laryngeal Nerve (RLN)

Supplies sensation to subglottic area and controls all intrinsic laryngeal muscles except cricothyroid.

CN XI: Accessory Nerve

Purely motor nerve; innervates sternocleidomastoid and trapezius muscles.

CN XII: Hypoglossal

Controls intrinsic and extrinsic muscles of the tongue, with contributions to tongue movement.

Intrinsic Muscles of the Tongue

Responsible for changing the size and shape of the tongue, have no external origin.

Cervical Plexus

Innervates certain muscles including geniohyoid, with clinical relevance to swallowing.

Ansa Cervicalis

A nerve loop innervating the infrahyoid muscles, important in stabilizing the hyoid.

Parasympathetic Control

Regulates salivary glands, including submandibular and sublingual glands.

Exceptions to CN Innervation

Palatoglossus is an extrinsic muscle of the tongue innervated by CN X, not CN XII.

Clinical Tip - Swallowing

Suprahyoids aid jaw opening; lateral pterygoid is the primary contributor to mastication.

Clinical Tip - RLN Paralysis

Ansa cervicalis could be considered for laryngeal reinnervation due to its muscular role.