Anatomy Lecture 3 (Lumbar & Sacral Plexuses) - PDF

LUMBAR PLEXUS Spinal nerves L1 – L4 with the contribution from anterior ramus of T12 T12 Subcostal n. Iliohypogastric n. T12 - L1 L1 Ilioinguinal n. L1 Genitofemoral n....

LUMBAR PLEXUS Spinal nerves L1 – L4 with the contribution from anterior ramus of T12 T12 Subcostal n. Iliohypogastric n. T12 - L1 L1 Ilioinguinal n. L1 Genitofemoral n. L1 - L2 L2 Lateral Femoral Cutaneus n. L2 - L3 L3 L4 Femoral n. L2 - L4 Obturatoe L2 - L4 0 ILIOHYPOGASTRIC NERVE (T12 - L1) Upper lateral border of the psoas major m. – in front of quadratus lumborum m. – pierces the transvers abdominal m. (iliac crest) Anterior cutaneous branch Lateral cutaneous branch ILIOHYPOGASTRIC NERVE – SENSORY INNERVATION Lateral cutaneous branch – skin of the posterolateral gluteal region Anterior cutaneous branch – skin of the suprapubic region ILIOHYPOGASTRIC NERVE – MOTOR INNERVATION Transvers abdominis muscle Internal oblique muscle Conjoint tendon  ILIOHYPOGASTRIC NERVE DAMAGE Surgical trauma - open approach to the appendix. Transverse incisions of the lower abdomen, during a hysterectomy Sport injury Pregnancy - rapid expansion of the abdomen in the third trimester. Clinical Signs: burning pain in the suprapubic and inguinal ILIOINGUINAL NERVE (L1) Posterior to the psoas major - the anterior surface of the quadratus lumborum – transvers abdominis m. - passes through the internal oblique m. to enter the inguinal canal - exits it through the superficial inguinal ring ILIOINGUINAL NERVE – SENSORY INNERVATION Anterior labial/scrotal nerves Skin over the pubis (genital region) Superior antero-medial thigh ILIOINGUINAL NERVE – MOTOR INNERVATION Supplies: transvers abdominis muscle internal oblique muscle.  ILIOINGUINAL NERVE DAMAGE Trauma – the surgical trauma of transversus abdominus and internal oblique muscles. Inguinal incisions carried out to repair inguinal hernias are a high-risk incision and may injure the ilioinguinal nerve. Pregnancy - rapid expansion of the abdomen in the third trimester Clinic: a chronic pain in the groin region lasting for greater than 3 months following inguinal hernia repair surgery. Treatment: analgesia or physical therapy; nerve blockage. GENITOFEMORAL NERVE (L1-L2) After leaving the psoas major muscle, the genitofemoral nerve quickly divides into: Femoral branch Genital branch GENITOFEMORAL NERVE – SENSORY INNERVATION Femoral branch – the skin of the anterior, upper, and medial aspects of the thigh Genital branch: Males: anterior scrotal skin Females: mons pubis, labia majora GENITOFEMORAL NERVE – MOTOR INNERVATION Genital motor branch - Cremaster muscle in males. LATERAL FEMORAL CUTANEOUS NERVE (L2 - L3) Emerges from the lateral border of the psoas major m. – iliac fossa - passes inguinal ligament - emerges anterior to the sartorius m. Sensory: supplies the parietal peritoneum of the iliac fossa.  LATERAL FEMORAL CUTANEOUS NERVE Sensory: innervates the skin of the anterior and posterior lateral thigh to the knee.  FEMORAL NERVE (L2 – L4) Emerges from the lower lateral border of the psoas major muscle and passes below the inguinal ligament - reaches the thigh. Mixed nerve that provides motor and sensory innervation to the thigh and leg. FEMORAL NERVE – SENSORY INNERVATION Branches: Anterior cutaneous branch Saphenous nerve (longest nerve) Skin of the anteromedial thigh Skin of medial leg and foot OBTURATOR NERVE (L2 – L4)  The obturator n. enters the medial thigh via the obturator canal.  Motor supply: Obturator externus Adductor longus Adductor brevis Adductor magnus Gracilis Pectineus OBTURATOR NERVE – MOTOR INNERVATION HIP ADDUCTORS OBTURATOR NERVE – SENSORY INNERVATION Skin over the proximal part of the medial thigh and articular branch for the hip and MOTOR FUNCTIONS OF THE OBTURATOR NERVE Bending and extending the leg from your thigh to the knee Flexing the hip Moving the thighs together Rotating the foot and leg Staying balanced while standing upright SACRAL PLEXUS The sacral plexus is located on the posterior pelvic wall. Formed by ventral rami of L4- L5 and S1-S4  POSTERIOR BRANCHES Superior gluteal nerve (L4 - S1) – superior border of piriformis m. through the greater sciatic foramen Tensor fasciae latae Gluteus medius muscle Gluteus minimus muscle SACRAL PLEXUS Inferior gluteal nerve (L5 - S2) – anterior rami - greater sciatic foramen, inferior to piriformis m., superficial to sciatic nerve. Gluteus maximus m. Perforating cutaneous nerve (S2 - S3) – anterior rami - greater sciatic foramen Inferior medial part of the buttock – cutaneous supply SACRAL PLEXUS - POSTERIOR BRANCHES Posterior femoral cutaneous nerve (S1– S3) – leaves the pelvis via the greater sciatic foramen - deep to the gluteus maximus and - the back of the thigh to the knee. Posterior surface of the thigh and leg SACRAL PLEXUS - ANTERIOR BRANCHES  Nerve to the quadratus femoris (L4 - S1) - leaves the pelvic cavity through the greater sciatic foramen, enters gluteal region  Quadratus femoris m.  Inferior gemellus m.  Hip joint (articular branch)  Nerve to obturator internus (L5 - S2) - leaves the pelvic cavity through the greater sciatic foramen – enters the lesser sciatic foramen  Obturator internus m.  Superior gemellus m. SACRAL PLEXUS - ANTERIOR BRANCHES  Pudendal n. (S2 - S4) Motor function  Perineum muscles  External urethral sphincter  External anal sphincter  Levator ani Sensory  Penis/clitoris  Skin of the perineum  SCIATIC NERVE (L4 – S3) Exits the pelvic cavity via the greater sciatic foramen - gluteus maximus - post. surface of the gemelli, piriformis, quadratus femoris mm. - post. femoral region popliteal fossa. Branches: Tibial nerve Common fibular nerve  Tibial nerve Branchesto muscles Sensory rami to (deep & superficial) knee joint Med. calcaneal Med. Plantar n. Lat. Plantar n. branches (mix)  TIBIAL NERVE  Innervation - posterior muscles of leg (hip extensors and knee flexors) except the short head of the biceps femoris (innervated by the common fibular nerve)  Branches:  Superficial and deep muscles  Sensory rami to knee joint.  Medial sural cutaneous n.  Terminal branches:  Medial plantar (I to medial aspect of IV)  Lateral plantar (lateral aspect of IV and V)  Medial calcaneal branches TIBIAL NERVE BRANCHES TO SUPERFICIAL MUSCLES Posterior compartment of the leg Superficial: Plantaris (plantarflexion of the ankle) Soleus (plantarflexion of the ankle) Gastrocnemius (flexion of the knee and plantarflexion of the ankle)  TIBIAL NERVE BRANCHES TO DEEP MUSCLES Posterior compartment of the leg Deep: Popliteus (lateral rotation of the knee) Flexor hallucis longus (flexion of the great toe and plantarflexion of the ankle) Flexor digitorum Longus (flexion of digits 2-5 and plantarflexion of the ankle) Tibialis posterior (inversion of the foot and plantarflexion of the ankle). Exclusion: short head of biceps femoris LATERAL & MEDIAL PLANTAR, MEDIAL CALCANEAL NERVES COMMON FIBULAR NERVE Deep fibular nerve Superficial fibular nerve Lateral sural (cutaneous) n. that joints with the medial sural n. (branch of the tibial nerve) and forms sural n. Sensory innervation of the sural nerve: posterolateral leg and lateral side of the foot. THE SUPERFICIAL FIBULAR (PERONEAL) NERVE The superficial fibular nerve Motor function (Lat. muscles of the leg): Fibularis longus Fibularis brevis Sensory function: Distal anterior surface of the leg Dorsum of the foot THE SUPERFICIAL FIBULAR (PERONEAL) NERVE THE DEEP FIBULAR (PERONEAL) NERVE (L4-S1) Motor function: muscles in the anterior compartment of the leg Tibialis anterior Extensor digitorum longus Extensor hallucis longus Sensory function: the triangular region of skin between the 1st and 2nd toes. SURAL NERVE (S1-S2)  Origination: Medial sural cutaneous (branch of tibial n.) Lateral sural cutaneous (branch of common fibular n.) Branches of the sural nerve: Lat. dorsal cutaneous n. of foot Lat. calcaneal branches  SCIATIC NERVE INJURY MANIFESTATION CAUSES Pain – often shoots and radiates down Herniated discs the leg Degenerative disk diseases Paresthesia Injuries Numbness Pregnancy Muscle weakness Tumors, cysts, etc. SUPERIOR GLUTEAL NERVE INJURY TRENDELENBURG SIGN Found in patients with damage to the superior gluteal nerve. When the patient stands on the affected limb, the pelvis severely drops over the swing limb.  LINKS https://www.youtube.com/watch?v=18oQiiZKjzQ&t=69s https://www.youtube.com/watch?v=dKsnNi2APDA&t=378s THANK YOU