Lower Limb Anatomy PDF

LOWER LIMB Overview of entire lower extremity Plus, detailed Gluteal Region Thigh Popliteal Fossa Objectives 1. 2. 3. 4. 5. 6. 7. Know the general pattern of innervation of the major compartments of the lower limb and relate them to rotation during development. Describe the dermatomal pattern of inn...

LOWER LIMB Overview of entire lower extremity Plus, detailed Gluteal Region Thigh Popliteal Fossa Objectives 1. 2. 3. 4. 5. 6. 7. Know the general pattern of innervation of the major compartments of the lower limb and relate them to rotation during development. Describe the dermatomal pattern of innervation of the lower limb and compare it to that of the upper limb. Be able to discuss the actions, innervations and names of all the muscles in the anterior, posterior and medial compartments of the thigh and the gluteal region. Discuss the blood supply of the lower limb with an emphasis on collateral circulation and venous return. Relate the position of the sciatic nerve to the acceptable location for a gluteal injection. Understand the importance of the gluteal muscles in the process of normal gait. Know the Trendelenburg gait and the cause. Discuss the blood supply of the gluteal region and the thigh. Pay special attention to anastomotic connections and the blood supply to head of the femur. Medial rotation of lower limb The lower limb undergoes 180 degree medial rotation so that the original posterior compartment becomes the adult anterior compartment Medial rotation of lower limb Femoral Posterior fetal !8 l ora m e F Obturator atic Sci Sciatic O r rato u t b 180 degree medial rotation of lower limb Anterior Anterior Anterior Posterior Birth Femoral Obturator Sciatic Posterior 8-12 months Looking at a section of the left thigh from below Lumbo-Sacral Plexus You will not be expected to draw out or reproduce this plexus, but you will need to know the levels involved in each of the following nerves: femoral L2,3,4, obturator L2,3,4, and sciatic L4,5 S1,2,3. Nerves shaded in black are posterior division nerves innervating fetal posterior compartment muscles and those in white anterior division to fetal anterior compartment muscles Final Pattern of Innervation in the Adult Lower Extremity Anterior division nerves found in the adult posterior compartments Tibial: posterior thigh, posterior leg, plantar foot Obturator: medial thigh Posterior divsion nerves found in the adult anterior compartments femoral (thigh); gluteals (hip); fibular (peroneal) (thigh, leg, foot) Some applications of the innervation patterns in the adult extremities Terminal nerves from a plexus innervate muscles by groups or compartments. Muscles in a compartment or group share similar functions. The lower limb has three compartments in the thigh and three in the leg all with different nerve supplies. Compartment Thigh Leg Anterior Femoral Posterior Tibial/peroneal Tibial Medial Obturator None Lateral None Peroneal Peroneal Relation of spinal cord segments to movement in the extremities Upper extremity Shoulder joint Elbow joint Wrist joint Intrinsic hand muscles C5-6 C6-7 C7-8 C 8 T1 Lower extremity Anterior compartment muscles Hip Flexion L2-3 Posterior compartment muscles Hip extension L4-5 Knee Extension L3-4 Knee Flexion L5-S1 Ankle dorsiflexion L4-5 Ankle plantarflexion Plantar foot muscles S1-2 S2-3 Dermatomes of lower limb The dermatome of the little toe is S1 The dermatome of the big toe is L4/5 The dermatomes of the anterior and medial thigh are L 2,3,4 which are also the nerve roots contributing to the femoral and obturator nerves which supply the anterior and medial thigh compartments The lower limb (extremity) is specialized for locomotion and to support body weight What does this necessitate for joint and muscle structure 1. Muscles need a good blood supply and must be large 2. Joints must sacrifice mobility for strength Four Segments of the Lower Limb: 1. Pelvic girdle; hip bones +sacrum 2. Thigh 3. Leg 4. Foot Moore, p. 559 Pelvic Girdle Ligaments: Sacroiliac Sacrotuberous Sacrospinous Netter (4th) 353 Bones and Ligaments of the Pelvis Obturator membrane - Obturator canal - Ligaments of the hip joint Clemente, Fig. 388 Femur Head Fovea for ligament of head Gluteal tuberosity Neck Linea aspera Greater & lesser trochanter Shaft Supracondylar ridges (medial and lateral) Lateral & medial epicondyle Medial and lateral condyles Netter 471; Moore p. 564 Femoral Fractures Femoral neck fracture are especially serious due to possibility of blood supply interruption; Spontaneous regression of supply in children= Legg Calve Perthes disease. Moore, p. 566 Thigh Nerves and Compartments of Thigh Netter (4th) 505 and Grant’s Dissector Fig. 5.25 Lymphatics and Superficial Veins of the Lower Limb Inguinal nodes Popliteal nodes Both groups ultimately drain to the external iliac and then the lumbar trunks of the cisterna chyli Superficial veins are the greater and lesser saphenous. Varicose veins-due to incompetent valves between the superficial and deep vessels Netter (4th) 546 Arteries of Thigh and Knee External iliac (above inguinal ligament) Femoral artery Deep artery (profunda femoris) medial and lateral femoral circumflex supply head of femur Popliteal artery Anastomoses around knee Tibial/Fibular trunk Anterior tibial Netter (4th) 512 Arteries of Thigh Medial Femoral Circumflex off the Profunda Lateral Femoral Circumflex off the Profunda 1st Perforating off the Profunda. Profunda is only blood supply to posterior compartment via perforators Descending branch of Lateral Femoral Circumflex can bypass a blocked femoral artery Netter (4th) 512 Part B: Deep fascia; saphenous opening; anterior and medial regions of thigh Fascia of the Thigh Fascia Lata surrounds the thigh and has extensions that divide it into three compartments Grant’s Dissector, Fig. 5.8 Femoral Triangle and Contents Clinical Correlation Femoral artery: Femoral pulse Catheterization (aorta and branches, coronary arteries, mesenteric arteries). Femoral vein: Catheterization (inferior vena cava, right heart, pulmonary circulation) Grant’s Dissector, Fig. 5.7A+B Saphenous opening and Femoral Sheath !"#$%&'()*"&+*(&,-(.+)( +*%""(/$#0&%+#",+) Lateral: femoral artery Middle: femoral vein Medial (= femoral canal): lymphatics; femoral hernia. Note: the femoral nerve lies lateral to the femoral sheath Sheath is made of transversalis fascia which blends with the fascia of the thigh Grant’s Dissector, Fig. 5.5 (lower part) Femoral Sheath Anterior thigh and femoral nerve distribution Psoas & Iliacus Muscles Converge as they exit the pelvis to form the iliopsoas muscle They insert on the lesser trochanter and have an action at the hip joint to flex the thigh Innervation is by femoral nerve and ventral rami of L1,2,3. Just call it femoral. Psoas Iliacus Anterior Thigh Pectineus Just medial to iliopsoas Sartorius Tailor’s muscle Quadriceps Femoris Rectus femoris Vastus lateralis Vastus intermedius Vastus medialis All of these are innervated by the femoral nerve although pectineus may also be innervated by the obturator n. Quadriceps femoris Extension of leg at knee joint; rectus also flexes thigh Moore Flexors of the Hip Joint Tensor Fascia Lata is really a gluteal muscle by innervation, but it can assist with thigh flexion and is seen during dissection of the anterior compartment Vessels and Nerves of Anterior Thigh The saphenous nerve off the femoral is the only branch of the femoral that passes distal to the knee. It is cutaneous. Adductor canal Saphenous nerve, travels with the artery and vein in adductor canal but does not follow the femoral vessels into the popliteal fossa Netter (4th) 500 Adductor Canal Adductor canal (subsartorial canal; Hunter’s canal). The narrow space in the middle third of the thigh between the vastus medialis and adductor muscles, converted into a canal by the overlying sartorius muscle. It extends from the apex of the femoral triangle to the adductor hiatus (in the tendon of the adductor magnus) It contains the femoral vessels and the saphenous nerve. Adductor Canal in Cross Section Course of femoral vessels and saphenous nerve Grant’s Dissector, Fig. 5.8 & Netter (4th) 505 Femoral Nerve Arises from L2-4 and supplies muscles of anterior thigh group as well as the Iliopsoas muscle. Important for thigh flexion and knee extension Grant’s Dissector Fig. 5.9 Cutaneous Distribution of Femoral Nerve (Blue) Anterior cutaneous branches Saphenous nerve Lateral femoral cutaneous (red) Netter (4th) 538 Medial Thigh - Adductors Adductor longus Gracilis This group adducts and medially rotates the thigh Innervated by the obturator nerve Medial Muscle Group of Thigh Two parts: adductor and hamstring with different innervations Obturator externus has different function than all the other medial group muscles-lateral rotator Moore, p. 599 Obturator Nerve Nerve to adductor compartment; Sometimes the Pectineus Upper (adductor) part of magnus Lower (hamstring part) is from the sciatic Grant’s Dissector, Fig. 5.11 Motor Branches of Obturator Nerve Medial region of thigh: The adductor group is supplied by the obturator nerve. Exits the obturator foramen under the pectineus and then splits around adductor brevis Adductor Hiatus opening for femoral vessels Grant’s Dissector, Fig. 5.12 Gluteal Region and Posterior Thigh Cluneal Nerves cutaneous innervation of the gluteal region Superior (dorsal rami L1-L3) Medial (dorsal rami S1-S3) Inferior (branch of posterior cutaneous nerve of thigh) Netter (4th) 545 Gluteal Muscles 1. 2. 3. 4. Gluteus maximus Gluteus medius Gluteus minimus Tensor fasciae latae 2 1 2 3 2 1 4 Gluteal Attachments Gluteus medius & minimus: Gluteal surface & lines of ala (wing) of ilium; Greater trochanter of femur Gluteus maximus: Ilium, sacrum, sacrotuberous ligament; Iliotibial tract, gluteal tuberosity of femur Netter (4th) 491 Gluteus Maximus !"#$%&'(#)*+)(,-'(*%(.*'*%+( /.01(#)$('*##*%+(20'*#*0%3 4''*'#'(*%(5-#$.-5(.0#-#*0% !"#$%#&#'"(%)'*% !"#$%#&#'"(%)'*% Netter (4th) 494 + 495A https://www.wnycstudios.org/po dcasts/radiolab/articles/managainst-horse Gluteal region / Gluteus medius & minimus 46&78#(-%&(1$&*-559(.0#-#$(#)*+):(;$$2(2$5