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\b[The four names identify distinct pathways: <chorda tympani>, the sensory <buccal nerve>, the <radial nerve> formerly called musculospiral, and the <obturator nerve>.] Origin must include the parent <nerve> or <nerve plexus>, while the function must follow the actual fibre supply rather than the name of a structure crossed.
\b[<Chorda tympani>.] This branch leaves the <facial nerve> in its descending facial canal before the <stylomastoid foramen>. It enters the <tympanic cavity> from behind, passes forwards between the <malleus> and <incus> close to the inner surface of the <tympanic membrane>, and leaves through the <petrotympanic fissure>. In the <infratemporal fossa> it joins the <lingual nerve>, a branch of the mandibular division of the <trigeminal nerve>. It then travels with that carrier towards the <tongue> and <submandibular ganglion>.
The <chorda tympani> carries taste from the anterior two thirds of the <tongue>, with sensory cell bodies in the <geniculate ganglion> and central connections to the <nucleus of the solitary tract>. It also carries preganglionic <parasympathetic> fibres from the <superior salivatory nucleus> towards the <submandibular ganglion>; postganglionic fibres supply the <submandibular gland> and <sublingual gland>. It does not provide the general touch supply of that part of the <tongue>; that travels through the <lingual nerve>'s <trigeminal nerve> pathway. Taste and tactile testing can consequently distinguish two functions that briefly share one peripheral trunk.<Anatomy, Head and Neck, Chorda Tympani (StatPearls)>[Introduction; Structure and Function: facial origin, middle-ear passage, lingual connection and gustatory/secretomotor fibres]{ref}
\b[<Buccal nerve>.] In the usual anatomical meaning intended by this list, this is the long <buccal nerve> from the anterior division of the mandibular <trigeminal nerve>. It commonly emerges between the heads of the <lateral pterygoid muscle>, descends near the anterior border of the mandibular ramus and the <temporalis muscle> insertion, and passes towards the cheek. Its branches reach cheek <skin>, the <buccal mucosa>, and the buccal <gingiva> beside the lower molars. It is principally sensory. The motor supply of the <buccinator muscle> comes from the <facial nerve>, whose buccal branches are a different set of <nerves>. Thus the ability to hold the cheek against the teeth and sensation in the cheek are not tests of the same efferent pathway.<Anatomy, Head and Neck: Buccal Nerve (StatPearls)>[Introduction; Structure and Function: mandibular origin, relations to lateral pterygoid and sensory distribution]{ref}
\b[<Radial nerve>, historically musculospiral.] This is the major continuation of the posterior cord of the <brachial plexus>, usually containing fibres from C5–T1. It passes from the <axilla> into the posterior arm, accompanying the <profunda brachii artery> in the <radial groove> of the <humerus>. It pierces the lateral intermuscular septum and reaches the anterior compartment between <brachialis> and <brachioradialis>. Near the lateral elbow it divides into a superficial sensory branch and a deep motor branch. The latter passes through the <supinator muscle> and continues as the <posterior interosseous nerve>.
The <radial nerve> supplies <triceps brachii> and <anconeus>, then <brachioradialis>, the radial wrist extensors and, through its deep continuation, the principal finger and thumb extensors and associated posterior forearm <muscles>. Its sensory branches supply posterior arm and forearm regions and part of the dorsolateral hand. A lesion's level matters: an arm lesion can impair wrist and finger extension, while an isolated superficial branch lesion is sensory and does not itself cause a wrist drop. Conversely, a <posterior interosseous nerve> lesion chiefly affects motor function. The fingertip pads are not the characteristic autonomous sensory territory of the superficial <radial nerve>.<Anatomy, Shoulder and Upper Limb, Radial Nerve (StatPearls)>[Structure and Function; Sensory; Motor; Muscles; Physiologic Variants]{ref}
\b[<Obturator nerve>.] It arises from the anterior divisions of the anterior rami of L2–L4 in the <lumbar plexus>. It emerges from the medial border of <psoas major>, crosses the pelvic side wall and leaves through the <obturator canal> with the <obturator vessels>. Its anterior and posterior divisions characteristically run on opposite sides of <adductor brevis>, although the level of division varies. The anterior division supplies <adductor longus>, <gracilis> and commonly <adductor brevis>; the posterior division supplies <obturator externus> and the adductor portion of <adductor magnus>, with variable additional contributions. The hamstring portion of <adductor magnus> has a different supply. Cutaneous supply to a variable medial-thigh patch and articular branches to the <hip> and <knee> supplement its principal motor role in thigh adduction. <Obturator internus> is supplied by its own sacral-plexus <nerve>, not by the <obturator nerve> merely because the names resemble one another.<Anatomy, Abdomen and Pelvis, Obturator Muscles (StatPearls)>[Nerves: L2–L4 supply of obturator externus versus separate supply of obturator internus]{ref}<Obturator Nerve by the National Library of Medicine>[MeSH definition: lumbar origin, thigh adductors and medial-thigh sensation]{ref}
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