Lower Limb What is a limb? Skeleton Joints Pelvis or limb girdle Hip/Hip Muscles Lumber and sacral plexus—getting spinal nerves out onto limb Muscles—anterior and posterior compartments Surface anatomy Skeleton (homologous with upper limb) Muscles--anterior, posterior compartments Nerves--sciatic, femoral Surface anatomy Frolich, Human Anatomy, Lower LImb

What is a limb? Ventral somatic outgrowth of outer tube Bones (made of bony tissue, cartilage, and other tissues) Joints Muscles Nerves (with motor neurons to muscles, sensory neurons to skin, proprioceptors) No viscera--all innervation is somatic (motor or sensory) from ventral ramus of spinal nerve (except autonomics to blood vessels) Frolich, Human Anatomy, Lower LImb

Lower Limb Upper Limb Pelvis Femur Tibia, fibula Tarsals Digits Metatarsals Phalanges Scapula Humerus Radius, ulna Carpals Digits Metacarpals Phalanges Frolich, Human Anatomy, Lower LImb

Upper Limb Scapula Humerus Radius, ulna Carpals Digits Metacarpals Phalanges Frolich, Human Anatomy, Lower LImb

Frolich, Human Anatomy, Lower LImb

Tibia/fibula Tibia--big toe side Fibula--little toe side (no pronation/supination) Frolich, Human Anatomy, Lower LImb

Ankle Talus--forms ankle joint Calcaneus--forms heel Frolich, Human Anatomy, Lower LImb

Foot Function: Tarsals Metatarsals Phalanges Support weight Act as lever when walking Tarsals Talus = ankle Between tibia + fibula Articulates w/both Calcaneus = heel Attachment for Calcaneal tendon Carries talus Metatarsals Homologous to metacarpals Phalanges Smaller, less nimble Frolich, Human Anatomy, Lower LImb

Joints of Lower Limb Hip (femur + acetabulum) Knee (femur + patella) Ball + socket Multiaxial Synovial Knee (femur + patella) Plane Gliding of patella Knee (femur + tibia) Hinge Biaxial Frolich, Human Anatomy, Lower LImb

Joints of Lower Limb Proximal Tibia + Fibula Distal Tibia + Fibula Plane Gliding Synovial Distal Tibia + Fibula Slight “give” Fibrous Ankle (Tibia/Fibula + Talus) Hinge Uniaxial Frolich, Human Anatomy, Lower LImb pg 218

Lower Limb Movements Hip Knee Flexion/extension Abduction/adduction Lateral/medial rotation Knee Ankle Dorsiflexion/plantarflexion Inversion/eversion Toes Bending on posterior side is flexion (except hip) Bending on anterior sided is extension (except hip) Frolich, Human Anatomy, Lower LImb

Pelvic tilt and a reverse lumbar curve (or how we got to be upright) Bowl concept pelvis spills forward Hernia “beer belly” In human minor pelvis is behind (posterior) to guts and abdominal cavity Compare human pelvic position with quadruped (cat for instance) Frolich, Human Anatomy, Lower LImb

Human pelvis still has quadruped orientation Frolich, Human Anatomy, Lower LImb

Bony structure of the pelvis MAIN STRUCTURES Hip bone (innominate, os coxae)--fusion of Ilium (“hips”) Ischium (“rear”) Pubis (anterior midline) Sacrum and coccyx Acetabulum Femur--head, neck, greater trochanter HOLES False and true pelvis (major, minor pelvis) Pelvic inlet, pelvic outlet Sacrotuberous ligament Sacrospinous ligament Greater, lesser sciatic foramen Obturator foramen Frolich, Human Anatomy, Lower LImb

Frolich, Human Anatomy, Lower LImb

Female Male Cavity is broad, shallow Pelvic inlet oval + outlet round Bones are lighter, thinner Pubic angle larger Coccyx more flexible, straighter Ischial tuberosities shorter, more everted Cavity is narrow, deep Smaller inlet + outlet Bones heavier, thicker Pubic angle more acute Coccyx less flexible, more curved Ischial tuberosities longer, face more medially Frolich, Human Anatomy, Lower LImb

Posterior and lateral hip Gluts (gluteal nn.) Maximus—extensor of thigh Medius--pelvic tilt (relative to insertion with foot planted) Lateral rotators (spinal nn.) Piriformis syndrome Frolich, Human Anatomy, Lower LImb

Anterior Hip Iliopsoas Quadratus lumborum iliacus psoas Frolich, Human Anatomy, Lower LImb

Lumbar and sacral plexus Mr. Bill is happy—so easy Lumbar plexus forms femoral n.—anterior Sacral plexus forms sciatic n.--posterior Femoral n. Sciatic n. Frolich, Human Anatomy, Lower LImb

Sacral plexus (sciatic nerve) With leg out to side like quadruped, lumbar-anterior, sacral-posterior makes sense Lumbar plexus (femoral nerve) Frolich, Human Anatomy, Lower LImb

Dermatomes show twisting of leg during development Dorsal becomes anterior: thus “dorsiflexion” and extension in anterior compartment (unlike upper limb) Ventral becomes posterior: thus flexion is in posterior compartment (unlike upper limb) Frolich, Human Anatomy, Lower LImb

Anterior/Posterior compartments ANTERIOR COMPARTMENT POSTERIOR COMPARTMENT MOVEMENT Extension Flexion MUSCLES Quads Shin Hamstrings Gastrocs NERVES Femoral n. (lumbar plexus) Sciatic n. (sacral plexus) Frolich, Human Anatomy, Lower LImb

Thigh movements by compartment Frolich, Human Anatomy, Lower LImb

Anterior thigh (femoral n.) Sartorius (Tailor’s muscle) Quads (four) Rectus femoris (crosses hip) 3 vastus mm. (vast--big) Frolich, Human Anatomy, Lower LImb

Posterior thigh (sciatic n.) Hamstrings Biceps femoris Semimembranous Semitendinous Frolich, Human Anatomy, Lower LImb

Medial thigh (obturator n.) Adductor muscles Gracilis Adductor Magnus Longus brevis Frolich, Human Anatomy, Lower LImb

Leg movements by compartment (in leg all nn are branches of sciatic) Frolich, Human Anatomy, Lower LImb

Anterior Leg (deep fibular n.) Extensors (dorsiflexors) Fibularis (peroneus) longus Extensor digitorum longus Extensor hallicus longus Tibialis anteriorus Frolich, Human Anatomy, Lower LImb

Lateral Leg (superficial fibular n.) Fibularis brevis/longus Frolich, Human Anatomy, Lower LImb

Posterior Leg (tibial n.) Flexors (plantarflexors) Gastrocs and soleus Flexor digitorum longus Flexor hallucus longus Frolich, Human Anatomy, Lower LImb

Human gait Humans only large mammal marathoners, ultra-runners Prehistoric cultures hunted by exhausting large prey Bipedalism very efficient energetically Gastroc-Achilles spring One other large mammal more efficient—also bipedal Frolich, Human Anatomy, Lower LImb

Intrinsics of foot Frolich, Human Anatomy, Lower LImb

Surface Anatomy: Anterior Thigh + Leg pg 792 Surface Anatomy: Anterior Thigh + Leg Palpate Patella Condyles of femur Femoral Triangle Sartorius (lateral) Adductor longus (medial) Inguinal ligament (superior) Femoral a + v, lymph nodes pg 785 Frolich, Human Anatomy, Lower LImb

Surface Anatomy: Posterior Leg Popliteal fossa Diamond-shape fossa behind knee Boundaries Biceps femoris (sup-lat) Semitendinosis + semimembranosis (sup-med) Gastrocnemius heads (inf) Contents Popliteal a + v Calcaneal (Achilles) tendon Frolich, Human Anatomy, Lower LImb pg 793

Blood supply to lower limb Internal Iliac Cranial + Caudal Gluteals= gluteals Internal Pudendal = perineum, external genitalia Obturator = adductor muscles External Iliac Femoral = lower limb Deep femoral = adductors, hamstrings, quadriceps Popliteal (continuation of femoral) Geniculars = knee Anterior Tibial = ant. leg muscles, further branches to feet Posterior Tibial = flexor muscles, plantar arch, branches to toes Frolich, Human Anatomy, Lower LImb