Anatomy of Skeletal Muscle on Lower Extremity
Seung Yeol Lee, M.D.Department of Orthopaedic Surgery, Seoul National University Bundang Hospital
Anterior Muscles of Pelvis
Origin : T12-L5 vertebraInsertion :lesser trochanterAction : powerful hip flexion
Psoas Major
Psoas MinorOrigin : T12 & L1 vertebraInsertion : pectineal lineAction : weak flexion of trunk
IliacusOrigin :iliac fossaInsertion : lesser trochanterAction : powerful hip flexion
Gluteal Muscles
Origin :ilium & dorsal sacrumInsertion 1. gluteal tuberosity2. iliotibial bandAction 1. powerful
extension 2. ER of hip
Gluteal Maximus
Origin:ilium between anterior & posterior gluteal linesInsertion:greater trochanterAction: 1. powerful abduction 2. IR of hip3. Balancing during walking
Gluteal Medius
Origin: ilium between anterior & inferior gluteal linesInsertion: anterior greater trochanterAction:1. abduction & IR of
hip2. Assist gluteus
medius during walking
Gluteal Minimus
Trendelenburg sign
Origin: anterior sacrumInsertion: superior greater trochanterAction:1. hip ER2. hip abduction
during flexion
Piriformis
Origin1. ischiopubic rami 2.obturator mem-braneInsertion: medial greater trochanterAction: 1. hip ER 2. hip abduction during flexion
Obturator internus
Origin: ischial spine(sup.)ischial tuberosity(inf.)Insertion: medial greater trochanterAction:1. hip ER2. hip abduction
during flexion
Sup. & Inf. gemellus
Origin: ischial tuberosityInsertion: intertrochanteric crestAction: hip ER
Quadratus femoris
Posterior Femoral Muscle(Hamstrings)
Origin: ischial tuberosityInsertion: head of fibulaAction: 1. hip extension2. knee flexion & ER
Biceps Femoris (long head)
Origin: 1. linea aspera,2. supracondylar
lineInsertion: fibula, lateral tibiaAction: knee flexion & ER
Biceps Femoris (short head)
Origin: ischial tuberosityInsertion: proximal medial tibiaAction:1. hip extension2. knee flexion & IR
Semitendinosus
Origin: ischial tuberosityInsertion: posterior medial tibial condyleAction: 1. hip extension2. knee flexion & IR
Semimembranosus
Rectus Femoris muscle
Origin : 1. AIIS2. superior rim of
acetabulumInsertion :patella, tibial tubercleAction : 1. hip flexion2. knee extension
Triceps surae
Origin :Lateral and medial femoral condyleInsertion : Calcaneus( via Achilles tendon)Action : Knee flexion, ankle plantar flexion
Gastrocnemius
Origin :1. Posterior fibula head 2. Soleal line of tibiaInsertion : Calcaneus( via Achilles tendon)Action : ankle plantar flexion
Soleus
Origin :1. Posterior fibula head 2. Soleal line of tibiaInsertion : Calcaneus( via Achilles tendon)Action : ankle plantar flexion
Soleus
The Anterior and Lat Com-partment
(Extensor and Fibularis Groups)
Anterior TibialisOrigin :1. Upper 2/3 of lat. Surface
of tibia2. Crural interosseous
membrane3. Highest part of
Superficial crural fasciaInsertion : 4. Medial and plantar
surface of medial cuneiform
5. Medial base of metatarsal
Action : Ankle dorsiflexion Inversion
Fibularis longusOrigin :1. Head of fibula2. Proximal 2/3 of lateral
surface of fibulaInsertion : 3. Plantar side of medial
cuneiform4. Base of first metatarsal
Action : Ankle plantar flexion Eversion
The Posterior Compartment(Deep Flexor Groups)
Posterior TibialisOrigin :1. Crural interosseous
membrane and adjacent borders of tibia and fibula
Insertion : 2. Tuberosity of navicular,
cuneiforms, base of second fourth metatarsals
Action : Ankle plantar flexion Inversion
Flexor Hallucis longusOrigin :1. Distal 2/3 of posterior
surface of fibulaInsertion : 2. Base of distal phalanx of
big toeAction : Plantar flexion Inversion
Flexor Digitorum longus
Origin :1. Middle third of posterior
surface of tibiaInsertion : 2. Base of second through
fifth distal phalangesAction : Plantar flexion Inversion
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