The accessory nerve CN,四川大学华西临床医学院 临床医学（八年制）组长：宋慧子 组员：杨红梅、秦超毅、谢之易、蒋涵羽、李建华、云翥、胡敏、金夏、李千瑞,Company Logo,Accessory Nerve Outline,Company Logo,Accessory Nerve Outline,Company Logo,Accessory nerve Classifications,Traditional descriptions: Spinal part Cranial part Modern descriptions:Only the spinal part,Company Logo,Accessory Nerve Outline,Company Logo,Accessory Nerve Origin & Course,Origin： Spinal part: Spinal accessory nucleus-located in the lateral horn of the upper segment of the spinal cord.Cranial part:Nucleus ambiguus of the medulla oblongata,Company Logo,Accessory Nerve Origin & Course,Company Logo,Accessory Nerve Origin & Course,Course： Originates in the upper spinal cord Ascends and enters the skull through foramen magnum Courses along the inner wall 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 sending it motor branches, then continues inferiorly until it reaches the trapezius muscle to provide motor innervation to its upper portion.,Company Logo,Accessory Nerve Origin & Course,Cervical PlexusSchema,Company Logo,Accessory Nerve Origin & Course,Cervical PlexusIn Situ,Company Logo,Accessory Nerve Origin & Course,Company Logo,Accessory Nerve Outline,Company Logo,Accessory Nerve Functions & Innervations,Motor Innervation from the central nervous system SCM muscle: tilts and rotates the head Trapezius muscle: several actions on the scapula, including shoulder elevation and adduction of the scapula.,Company Logo,Accessory Nerve Functions & Innervations,Accessory n. innervates:The SCM muscleThe trapezius muscle,Company Logo,Accessory Nerve Functions & Innervations,Vagal Innervation provided by the thoracic branchesIn early embyrologic development of the mammalian heart, the vagal innervation is provided by the thoracic branches of the spinal accessory n.,Company Logo,Accessory Nerve Outline,Company Logo,Accessory Nerve Clinical Relevance,Injuries:Injury to the spinal accessory n. Accessory n. Disorder or Spinal Accessory n. Palsydiminished or absent function of The SCM Muscle and upper portion of The Trapezius MuscleAttention!Distal part of the spinal accessory n. is most susceptible to injury.,Company Logo,Accessory Nerve Clinical Relevance,Protections: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 Logo,Accessory Nerve Clinical Relevance,Injury Detections: Range of motion Strength testing of the neck and shoulders Limited range of motion or poor muscle strength are suggestive of damage to the spinal accessory n,Company Logo,Accessory Nerve Q & A,Company Logo,Accessory Nerve Acknowledgements,Great thanks toMis Hongying ZHOUMr Daobang CHEN,Thank you！,