Spinal Nerves 脊神经

Spinal nerves 脊神经 Formation: each spinal nerve is formed by union of anterior and posterior roots at intervertebral foramen The anterior root 前根－contains motor fibers for skeletal muscles. The posterior root后根－contains sensory fibers whose cell bodies are in the spinal ganglion脊神经节.

Spinal nerves 脊神经 Spinal ganglia脊神经节 is an enlargement of the posterior root near the intervertebral foramen which consist of the bodies of pseudounipolar neurons 假单极神经元。

Divisions of spinal nerves 脊神经的分部 31对脊神经分为5 部分 : cervical nerves 颈神经 8对 thoracic nerves 胸神经: 12对 lumbar nerves 腰神经: 5对 sacral nerves 骶神经 :5对 coccygeal nerve 尾神经: 1对

The fiber components of spinal cors 脊神经的纤维成分 There are four types of fibers contained in the spinal n. Somatic afferent (sensory) nerve fibers 躯体感觉纤维: 由脊神经节中的假单极神经元的中枢突形成，周围突分布于皮肤、骨骼肌、肌腱和关节。 Visceral afferent (sensory) nerve fibers 内脏感觉纤维: 也由脊神经节中的假单极神经元的中枢突形成, 周围突分布于内脏、心血管和腺体。 Somatic efferent (motor) nerve fibers 躯体运动纤维：发自脊髓前角，分布于骨骼肌。 Visceral efferent (motor) nerve fibers 内脏运动纤维：分布于心肌、平滑肌和 腺体。

branches of spinal nerves 脊神经的分支 Each spinal n. is divided into 4 branches after leaving the intervertebral foramen immediately anterior branche 前 支 posterior branche 后 支 meningeal branch 脊膜支 communicating branc 交通支: 连于交感干。

cervical plexus 颈丛、 branchial plexus 臂丛 lumbar plexus 腰丛 posterior branche 脊神经后支：为混合性，较细小， 分布于 项、背、 腰、骶部深层肌肉及皮肤。 anterior branche 脊神经前支：粗大，为混合性，除胸部外，前 支先交织成丛，然后再分支分布于躯 干前外侧 和四肢， 脊神经前支形 成的丛有： cervical plexus 颈丛、 branchial plexus 臂丛 lumbar plexus 腰丛 sacral plexus 骶丛。

二、cervical plexus 颈丛 Formation 构成： Branches分支： it consists of the anterior rami of C1-C4 nerves. Branches分支： Cutaneous branches皮支--分布到颈前部皮肤， Muscular brnches肌支--支配颈部深层的肌肉。    

Cutaneous branches: Lesser occipital 枕小神经 Great auricular 耳大神经 Transverse nerve of neck 颈横神经 Supraclavicular nerves 锁骨上神经 They emerge around middle of posterior border of sternocleidomastoid, to supply skin of neck and scalp between auricle and external occipital protuberance

Muscular branches: supply the deep muscles of neck Phrenic nerve 膈神经arises from the of C3-C5, innervation to diaphragm;

Phrenic nerve 膈神经 Sensory fibers supply to pleurae, pericardium and peritoneum of diaphragm; usually right phrenic nerve may be distributed on live, gallbladder and biliary system.

二、 brachial plexus臂丛   Formation ： Formed by anterior rami of C5-C8 and T1 nerves Position ： Passes through the scalene fissure (斜角肌间隙) to posterosuperior of subclavian artery, then enters the axilla to form three cords(束) which around the axillary atery. Medial cord 内侧束、 Lateral cord 外侧束 Posterior cord 后束

二、 brachial plexus臂丛 Branches 分支 Median nerve 正中神经 Musculocutaineous nerve 肌皮神经 Ulnar nerve 尺神经 Axillary nerve 腋神经 Radial nerve 桡神经

Anterior branche of thoracic nerve 胸神经前支 胸神经前支 共12对， Intercostal nerves 肋间神经（T1-T11）， 行于相应的肋间隙中； Subcostal nerve（T2） 肋下神经 ，第12肋下方。 Distribution: intercostales 肋间肌 anterolateral abdominal muscles腹前外侧壁肌；

Anterior branches of thoracic N The distribution of the anterior branches of the thoracic n. is segmental. T2 Sternal angle T4 Nipple 乳头 T6 Xiphoid process T8 Costal arch T10 Umbilicus 脐 T12 Midpoint between umbilicus and symphysis pubis

四、lumbar plexus腰 丛  Formation: anterior rami of L1-L3, a part of anterior rami of T12 and L4 position ：lies behind the psoas major and beside the lumbar vertera 腰椎两侧，腰大肌的深面，

branches： Femoral 股神经 Obturator 闭孔神经 Cutaneous 股外侧皮神经 Genitofemoral 生殖股神经 Iliohypogastric 髂腹下神经 Ilioinguinal 髂腹股沟神经 Lateral femoral

Femoral n. 股神经 disribution route： Runs downward and laterally between psoas major and iliacus, passes deep to inguinal ligament; disribution muscular branches---supplies anterior thigh muscles (quadriceps股四头肌, sartorius 缝匠肌and pectineus耻骨肌),

Femoral n. 股神经 sensory branches--- hip and knee joint, and skin on anteromedial side of thigh, saphenous nerve 隐神经 is distributed to skin of medial side of leg and foot

Obturator 闭孔神经 Route： Enters thigh through obturator foramen; Distribution： muscular branches--- supplies medial group of muscles of thigh股内侧群肌, obturator externus闭孔外肌, sensory branches--- skin of medial side of thigh

Lateral femoral cutaneous 股外侧皮神经 It arises from the lateral border of the psoas major and runs inferolateral to enter the thigh posterior to the inguinal lig.,just medial to the anterior superior iliac spine. it distribute to the skin over the lateral aspect of the thigh.

Genitofemoral 生殖股神经 It pierces the anterior surface of the psoas major and runs inferiorly ,and divide into femoral and genital branches股支和生殖支 The femoral branche distribute to the skin over the femoral triangle; and the genital branche distribute to the scrotum(greater lip of pudendum)

五、 sacral plexus 骶 丛 formation ： formed by anterior rami of L4 and L5 spinal nerves (the lumbrosacral trunk) and anterior rami of sacral and coccygeal nerves   Position: lies in pelvic cavity, anterior to sacrum and piriformis梨状肌

五、 sacral plexus 骶 丛 main branches Sciatic nerve 坐骨神经、   main branches Sciatic nerve 坐骨神经、 Pudendal nerve 阴部神经、 Superior gluteal n. 臀上神经 Inferior glureal n.臀下神经 。

Sciatic nerve 坐骨神经 Leaves pelvis through infrapiriform foramen to enter gluteal region, runs inferiorly deep to gluteus maximus, passing midway between the greater trochanter of femur and ischial tuberosity to back of thigh, lying deep to long head of biceps femoris, normally divided into tibial and common peroneal nerves just above popliteal fossa;

Sciatic nerve 坐骨神经 it innervates semitendinosus半腱肌, semimembranosus半膜肌and biceps femoris股二头肌

Tibial nerve 胫神经 Decends through popliteal fossa , then runs inferiorly with posterior tibial vessels and dividing into medial and lateral plantar nerves behind the medial malleolus内踝; supplies posterior muscles of leg and knee joint

Common peroneal nerve Arises at apex of popliteal fossa and follows medial border of biceps femoris and its tendon; passes over posterior aspect of head of fibula and then winds around neck of fibula, deep to peroneus longus, where it divides into deep and superficial peroneal nerves腓浅和腓深神经,to supply the anterior and lateral groups m. of the leg.

Superficial peroneal Deep peroneal