Presentation on theme: "Lower extremity neuroanatomy"— Presentation transcript:
1 Lower extremity neuroanatomy Wyndam M. Strodtbeck, MDSection Head, Acute PainDept of Anesthesiology and Pain MedicineVirginia Mason Medical Center
2 Disclosures No financial disclosures No off-label use of medications or devices will be discussedPatient permission was explicitly granted for any pictures used
3 Objectives for our talk Describe the clinical anatomy of the innervation of the lower extremityIdentify surrounding structures and their implications for sonoanatomy and potential variation
4 Lumbosacral plexus L1-L4 form the lumbar plexus Branches from L4 –S2 from the lateral trunkOther branches from L3-S3 make up the medial trunkS1-S5 make up the sacral plexusEarly branching of the lumbar plexus and thick musculature makes identifying a single compartment for lumbosacral blockade difficult
5 Early Branches of the Lumbar Plexus Ilioinguinal and iliohypogastric nervesFrom L1Iliohypogastric supplies anterior and lateral cutaneous innervation in hypogastric and gluteal regionIlioinguinal supplies cutaneous innervation of genital regionGenitofemoral nerveFrom L1 and L2Genital division supplies cremasteric muscle and sensory over genital regionFemoral branch supplies cutaneous innervation over femoral triangle
6 Early Branches of the Lumbar Plexus Gray, H. Anatomy of the human body, 1918.
7 Femoral Nerve Origin is dorsal divisions of L2-L4 Divides into anterior and posterior division typically at level of profunda femoris arteryNader, Relationship Between Ultrasound Imaging and Eliciting Motor Response, J Ultrasound Med, 28(3): , 2009
8 Femoral Nerve Anterior division Origin L2-L4Anterior division-Medial and intermediate cutaneous nerves-Muscular branches to sartorious-Articular branch to hip jointPosterior Division-Muscular branches to quads-Articular branches to knee joint-Saphenous nerve is terminal cutaneous branch and provides lower leg anteromedial sensationNader, Relationship Between Ultrasound Imaging and Eliciting Motor Response, J Ultrasound Med, 28(3): , 2009
9 Femoral NerveNader, Relationship Between Ultrasound Imaging and Eliciting Motor Response, J Ultrasound Med, 28(3): , 2009
10 Femoral Nerve Ultrasound image shows anterior and posterior divisions Keep in mind the variations in location and appearance of the nerveGroups of authors have reported variable splits in the femoral nerve in % of subjects.Nader, Relationship Between Ultrasound Imaging and Eliciting Motor Response, J Ultrasound Med, 28(3): , 2009
11 Lateral femoral cutaneous nerve Originates from dorsal divisions of L2 and L3May have a variable course as it emerges from psoasPasses under inguinal ligament and superficial to the sartorious muscleLocated between fascia lata and fascia iliacaResponsible for pain transmission in meralgia parestheticaHurdle, MF et al. Ultrasound-guided blockade of the lateral femoral cutaneous nerve. Arch Phys Med Rehab 88: , 2007.
12 Saphenous Nerve Terminal branch of posterior division of femoral nerve Provides cutaneous sensation around patella, anteromedial lower leg, and medial ankleTravels in adductor canal with femoral artery and veinIn distal thigh, the saphenous nerve can be identified deep to the sartorious and between the vastus medialis and the adductor magnus
13 Saphenous NerveImage courtesy of FV Salinas, MD
15 Obturator nerve Originates from ventral branches of L2-L4 Supplies articular branches to hip and kneeAdductors are suppliedSimilar to femoral nerve in having anterior and posterior divisions
16 Obturator nerve Anterior division Motor innervation to pectineus (may be an accessory obturator nerve) , adductor longus and brevis, gracilisArticular branch of the hipPosterior divisionMotor inneravtion to adductor magnus and brevis as well as obturator externusArticular branches to hip and knee
17 Nerves of the Sacral Plexus Gray, H. Anatomy of the human body, 1918.
18 Posterior femoral cutaneous nerve Provides sensation for posterior thigh and leg, gluteal region, and perineumOriginates from S1-S3
19 Posterior femoral cutaneous nerve Gray, H. Anatomy of the human body, 1918.
20 Sciatic Nerve Largest nerve in the body Joining of L4-S3 Two parts: -Tibial (medial)(L4-S2)- Common Peroneal(L4-S3)Provides sensation for posterior leg and foot (except for saphenous distribution) as well as motor for posterior thigh, and all of leg and foot, and articular branches for hip and kneeWikipedia, Feb 10, 2012
21 Sciatic NerveAt gluteal level, Sciatic is deep to gluteus maximus and passes out below piriformis muscle, located lateral to ischial spineThis level is useful due to the close proximity of the posterior femoral cutaneous nerve to the sciatic nerve
22 Sciatic NerveAt subgluteal level, the sciatic nerve is positioned between the gluteus maximus and the quadratus femoris
23 Sciatic NerveSubgluteal ultrasoundImage courtesy of FV Salinas, MD
24 Sciatic Nerve-Shared epineural sheath for tibial and common peroneal nerves separates above popliteal crease-Schwemmer et al (2005) demonstrated high variability for division of sciatic nerve above popliteal crease (1-15 cm with mean of 8 cm)Schwemmer et al. Sonographic imaging of the sciatic nerve division in the popliteal fossa. Ultraschall in Der Medizin, 2005.Wikipedia, Feb 10, 2012
25 Nerves of the ankle and foot Primarily consists of terminal branches from the sciaticException is the saphenous branch of the femoral nerveNYSORA.com, accessedGray, H. Anatomy of the human body, 1918.