All are true about Chorda tympani nerve except:

Ref: Grays Anatomy 40th edition pg: 543Explanation:Chorda tympani nerveIt is a branch of facial nerve arises within the facial canal 6mnrt above stylomastoid foramenIt enters the infratemporal fossa region by passing through the medial end of the petrotympanic fissure behind the capsule of the temporomandibular joint.The nerve descends medial to the spine of the sphenoid bone (lateral to spine of sphenoid auriculo temporal nerve will pass).It enter the mouth between the medial pterygoid muscle and ramus of the mandibleIt is crossed medially by the middle meningeal artery, the roots of the auriculotemporal nerve and by the inferior alveolar nerve .The chorda tympani joins the posterior aspect of the lingual nerve at an acute angleIt carries taste fibres for the anterior two-thirds of the tongue and efferent preganglionic parasympathetic (secreto-motor) fibres destined for the submandibular ganglion in the floor of the mouth.lt carries secretomotor fibers for both submandibular gland and sublingual gland .(See the following figure)