神经解剖学课件：The accessory nerve

1、The accessory nerve CNCompany LogoAccessory NerveOutlineClassifications1Origin & Course2Functions & Innervations3Clinical Relevance4Company LogoAccessory NerveOutlineClassifications1Origin & Course2Functions & Innervations3Clinical Relevance4Company LogoAccessory nerveClassificationsTraditional desc

2、riptions: Spinal part Cranial part Modern descriptions: Only the spinal partCompany LogoAccessory NerveOutlineClassifications1Origin & Course2Functions & Innervations3Clinical Relevance4Company LogoAccessory NerveOrigin & CourseOrigin：Spinal part: Spinal accessory nucleus -located in the lateral hor

3、n of the upper segment of the spinal cord.Cranial part: Nucleus ambiguus of the medulla oblongataCompany LogoAccessory NerveOrigin & CourseCompany LogoAccessory NerveOrigin & CourseCourse：Originates in the upper spinal cordAscends and enters the skull through foramen magnum Courses along the inner w

4、all of the skull towards the jugular foramen and exits the skull with CNIX and vagus nerve.In the neck, the accessory nerve crosses the internal jugular vein around the level of the posterior belly of digastric muscle.As it courses caudally, the nerve pierces the sternocleidomastoid muscle while sen

5、ding it motor branches, then continues inferiorly until it reaches the trapezius muscle to provide motor innervation to its upper portion.Company LogoAccessory NerveOrigin & CourseCervical Plexus SchemaCompany LogoAccessory NerveOrigin & CourseCervical Plexus In SituCompany LogoAccessory NerveOrigin

6、 & CourseCompany LogoAccessory NerveOutlineClassifications1Origin & Course2Functions & Innervations3Clinical Relevance4Company LogoAccessory NerveFunctions & InnervationsMotor Innervation from the central nervous system SCM muscle: tilts and rotates the head Trapezius muscle: several actions on the

7、scapula, including shoulder elevation and adduction of the scapula.Company LogoAccessory NerveFunctions & InnervationsAccessory n. innervates:The SCM muscleThe trapezius muscleCompany LogoAccessory NerveFunctions & InnervationsVagal Innervation provided by the thoracic branches In early embyrologic

8、development of the mammalian heart, the vagal innervation is provided by the thoracic branches of the spinal accessory n.Company LogoAccessory NerveOutlineClassifications1Origin & Course2Functions & Innervations3Clinical Relevance4Company LogoAccessory Nerve Clinical RelevanceInjuries: Injury to the

9、 spinal accessory n. Accessory n. Disorder or Spinal Accessory n. Palsy diminished or absent function of The SCM Muscle and upper portion of The Trapezius Muscle Attention! Distal part of the spinal accessory n. is most susceptible to injury. Company LogoAccessory Nerve Clinical RelevanceProtections

10、: Throughout much of its course, the nerve is protected from injury by the muscles it innervates. Attention! Injury to the spinal accessory n. is most commonly caused by medical procedures that involve the head and neck.Company LogoAccessory Nerve Clinical RelevanceInjury Detections: Range of motion Strength testing of the neck and shoulders Limited range of motion or poor muscle strength are suggestive of damag