Muscles of the Lower Limb

Movement at the Hip Joint Gluteus Maximus Superficial muscle of hip that forms flesh of buttock Most important for extending hip when power is needed Sacrum + iliac bones  gluteal tuberosity of femur + iliotibial tract

Movement at the Hip Joint Gluteus Medius Ilium  Femur Hip abductor, steadies the pelvis for walking Site for intramuscular injections Maximus overlies the sciatic nerve

Movement at the Hip Joint Iliopsoas Iliacus and psoas major Iliac bone lesser trochanter of femur Prime mover of hip flexion Keeps upper body from falling backwards while standing

Movement at the Hip Joint Adductor Muscles Form medial side of each thigh Press the thighs together Gravity does most of their work Pelvis  femur (proximally)

Movement at the Knee Joint Hamstrings Posterior thigh Biceps femoris, semimembranosus, semitendonosus Ischial Tuberosity  Proximal Tibia Prime movers of thigh extension and knee flexion Butchers use tendons to hang hams for smoking

Movement at the Knee Joint Sartorius Most superficial thigh muscle, thin, and strap-like Anterior iliac crest  Medial side of Tibia Weak thigh flexor “Tailor’s muscle”*

Movement at the Knee Joint Quadriceps 1 rectus femoris & 3 vastus muscles form anterior thigh Femur + Pelvis  Tibial Tuberosity by patellar ligament Extend the knee powerfully Rectus femoris helps flex hip RF + Vastus lateralis  intramuscular injections sites mostly for infants

Sartorius

Movement at the Foot & Ankle Tibialis Anterior Superior muscle on anterior leg Upper tibia  tarsal bones Acts to dorsiflex and invert foot

Movement at the Foot & Ankle Extensor Digitorum Longus Lateral tibial condyle + proximal radius  Phalanges 2-5 of foot Prime mover of toe flexion* Dorsiflexor of foot

Movement at the Foot & Ankle Fibularis Longus, brevis, tertius in lateral part of leg Fibula  Metatarsals Plantar flex and evert foot

Movement at the Foot & Ankle Gastrocnemius Two-bellied muscle forms cruved calf of posterior leg Two heads on each side of distal femur  through Calcaneal/Achilles tendon  heel If tendon breaks walking is impaired, heel cannot be lifted* Prime mover for plantar flexion “Toe dancer’s muscle”

Movement at the Foot & Ankle Soleus Fleshy muscle, strong plantar flexor Tibia and fibula  through Calcaneal/Achilles tendon  heel

Lower Limb Muscles Anterior View

Lower Limb Muscles Posterior View

Questions Which is the “tailor’s muscle”? A. Ipsoas C. Sartorius B. Gastrocnemius D. Rectus Femoris The prime mover of toe flexion is? A. Extensor Digitorum Longus C. Ipsoas B. Tibialis Anterior D. Fibularis A patient’s calcaneus/achilles tendon is cut during surgery, what will happen to him and why?

Sources Essentials of Human Anatomy, Ninth Edition Textbook http://wps.aw.com/wps/media/objects/5382/5 512191/ebook/htm/0ehap9.htm University of Michigan Medical School http://www.med.umich.edu/lrc/coursepages/m1/a natomy2010/html/anatomytables/muscles_lowerlim b.html Radiopaedia https://radiopaedia.org/articles/muscles-of- the-lower-limb