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

Thank you for your attention !!!