Lower Extremity Muscles Flashcards
Identify proximal and distal attachment sites, actions, and nerve innervation
Iliopsoas (L1-L4)
Anterior Compartment of thigh
Iliacus (L2-L4) PA: Iliac fossa, iliac crest, sacral ala & sacroiliac ligaments DA: Lesser trochanter of femur A: hip flexion & stabilization Femoral N. Innervation
Psoas major (L1-L4)PA:
PA: Anterior transverse processes, vertebral bodies & discs T12-L5
PA: Lesser trochanter of femur
A: hip flexion and stabilization
Ventral Rami L1-L4 Innervation (Lumbar plexus)
Rectus Femoris (L2-L4) (Anterior Compartment of thigh)
PA: AIIS - anterior inferior iliac spine & groove superior to the acetabulum
DA: Base of the patella
A: Hip flexion, Knee extension
Femoral N. Innervation
Sartorius (L2-L3)
Anterior Compartment of thigh
PA: ASIS - anterior superior iliac spine
DA: Medial aspect of the proximal tibia
A: Hip flexion, abduction, & lateral rotation; Knee flexion & assists medial rotation of knee
Femoral N. Innervation
Tensor Fascia Lata (L4, L5-S1)
Anterior Compartment of thigh
PA: ASIS - anterior superior iliac spine & external lip of iliac crest
DA: Iliotibial tract
A: Hip abduction, flexion, & medial rotation, assists in maintain knee extension (due to attachment to ITB)
Superior Gluteal N. Innervation
Vastus Intermedius (L2-L4) (Anterior Compartment of thigh)
PA: Anterior aspect of the proximal 2/3 of the femoral shaft
DA: Lateral border of the patella
A: Knee extension
Femoral N. Innervation
Vastus Lateralis (L2-L4) (Anterior Compartment of thigh)
PA: Intertrochanteric line, greater trochanter of femur, gluteal tuberosity & linea aspera
DA: Base of the lateral border of the patella
A: Knee extension
Femoral N. Innervation
Vastus Medialis (L2-L4) (Anterior Compartment of thigh)
PA: Intertrochanteric line, spiral line, linea aspera & medial supracondylar line
DA: Base & medial border of the patella
A: Knee extension
Femoral N. Innervation
Adductor Brevis (L2-L4) (Medial Compartment of thigh)
PA: Inferior pubic ramus
DA: Distal 2/3 pectineal line and medial lip of linea aspera
A: Hip flexion & adduction
Obturator N. Innervation
Adductor Longus (L2-L4) (Medial Compartment of thigh)
PA: Pubic crest
DA: Medial lip of linea aspera
A: Hip flexion, adduction, & medial rotation
Obturator N. Innervation
Adductor Magnus (L2-L4 adductor part) (L4, L5, S1 hamstring part) (Medial Compartment of thigh)
PA: Inferior pubic ramus, ischial ramus, & tuberosity
DA: Gluteal tuberosity, linea aspera (adductor part), medial supracondylar ridge & adductor tubercle of the femur (hamstring part)
A: Hip adduction & flexion (adductor part), Hip extension (hamstring part)
Obturator N. Innervation (adductor part)
Tibial division of Sciatic N. (hamstring part)
Gracilis (L2-L4)
Medial Compartment of thigh
PA: Body of pubic & inferior pubic ramus
DA: Medial surface of the tibia, distal to the condyle, proximal to the insertion of the semitendinosus, & lateral to the insertion of the sartorius
A: Hip flexion & adduction, medial rotation of the knee
Obturator N. Innervation
Pectineus (L2-L4)
Medial Compartment of thigh
PA: Superior pubic ramus
DA: Femur between lesser trochanter & linea aspera (pectineal line)
A: Hip flexion & adduction
Obturator N. & Femoral N. Innervation
Obturator Externus (L3-L4)***** (Medial Compartment of thigh)
PA: Rami of the pubis and ischium; external surface obturator membrane
DA: Trochanteric fossa
A: Hip lateral rotation
Obturator N. Innervation
Superior Gemellus (L5, S1-S2) (Gluteal muscle)
PA: External surface spine of ischium via obturator internus tendon
DA: Greater trochanter
A: Hip lateral rotation
Sacral Plexus Innervation
Inferior Gemellus (L4-L5, S1) (Gluteal muscle)
PA: Proximal ischial tuberosity via obturator internus tendon
DA: Greater trochanter
A: Hip lateral rotation
Sacral Plexus Innervation
Gluteus Maximum (L5, S1-S2) (Gluteal muscle)
PA: Aponeurosis of erector spinae, sacrum, sacrotuberous ligament & posterior gluteal line (innominate)
DA: Greater trochanter, gluteal tuberosity of the femur & iliotibial tract
A: Hip extension & lateral rotation
Inferior Gluteal N. Innervation
Gluteus Medius (L4-L5,S1) (Gluteus muscle)
PA: External iliac surface
DA: Oblique ridge on the lateral aspect of the greater trochanter; gluteal aponeurosis
A: Hip abduction & medial rotation; Keeps pelvis level when opposite leg raised –> Trendelenburg Gait if weak
Superior Gluteal N. Innervation
Gluteus Minimum (L4-L5, S1) (Gluteus muscle)
PA: External iliac surface & margin of the greater sciatic notch
DA: Anterolateral aspect of the greater trochanter
A: Hip abduction & medial rotation; Keeps pelvis level when opposite leg raised–> Trendelenburg Gait if weak
Superior Gluteal N. Innervation
Obturator Internus (L5, S1-S2) (Gluteal muscle)
PA: Anterolateral wall of the pelvis & obturator membrane
DA: Medial surface of the greater trochanter
A: Hip lateral rotation
Nerve to the Obturator Internus Innervation (from the sacral plexus)
Piriformis (S1-S2)
Gluteal muscle
PA: Anterolateral sacrum & posterior inferior iliac spine
DA: Superior border of the greater trochanter
A: Hip abduction & lateral rotation
Nerve to Piriformis Innervation
Quadratus Femoris (L4-L5, S1) (Gluteal muscle)
PA: Ischial tuberosity
DA: Quadrate tubercle of the femur
A: Hip lateral rotation
Nerve to the quadratus femoris Innervation (from sacral plexus)
Bicep Femoris (L5, S1-S3 Long head) (L5, S1-S2 Short head) (Posterior Compartment of thigh)
PA: Ischial tuberosity & sacrotuberous ligament (long head); Lateral lip of linea aspera & lateral supracondylar line (short head)
DA: Lateral side of the fibular head
A: Hip extension (long head only); Knee flexion & knee lateral rotation (both heads)
Tibial division of Sciatic N. Innervation (long head); Fibular division of Sciatic N. (short head)
Semimembranosus (L4-5, S1-S2)
Posterior Compartment of thigh
PA: Ischial tuberosity
DA: Posterior aspect of the medial tibial condyle
A: Hip extension; Knee flexion & medial rotation of knee
Tibial division of Sciatic N. Innervation
Semitendinosus (L4-L5, S1-S2)
Posterior Compartment of thigh
PA: Ischial tuberosity
DA: Proximal medial tibia
A: Hip extension; Knee flexion & medial rotation of the knee
Tibial division of Sciatic N. Innervation
Extensor Digitorum Longus (L4-L5, S1)
Anterior Crural (Leg) Compartment
PA: Lateral tibial condyle, proximal 3/4 of the fibula, & the crural interosseous. membrane
DA: Dorsal digital expansions of toes 2-5
A: Ankle dorsiflexion & Toe extension digits 2-5 (IP & MP)
Deep Fibular N. Innervation
Extensor Hallucis Longus (L4-L5, S1)
Anterior Crural Leg Compartment
PA: Middle 1/2 of fibular surface & crural interosseous membrane
DA: Distal phalangeal base of 1st great toe
A: Ankle dorsiflexion & Great toe extension (IP & MP)
Deep Fibular N. Innervation
Fibularis (Peroneus) Tertius (L4-L5, S1)
Anterior Crural Compartment
PA: Distal fibula & crural interosseous membrane
DA: Base of the 5th metatarsal
A: Ankle dorsiflexion & foot eversion
Superficial Fibular N. Innervation
Tibialis Anterior (L4-L5, S1) (Anterior Crural Compartment)
PA: Lateral condyle and proximal 2/3 of the tibia’s lateral surface & crural interosseous membrane
DA: Medial cuneiform & adjacent 1st metatarsal
A: Ankle dorsiflexion & foot inversion
Deep Fibular N. Innervation
Fibularis (Peroneus) Longus (L4-5, S1)
Lateral Crural Compartment
PA: Head & proximal 2/3 of the fibula
DA: Lateral aspects of the 1st metatarsal & adjacent medial cuneiform
A: Ankle plantarflexion, foot eversion, & 1st metatarsal head depression
Superficial fibular N. Innervation
Fibularis (peroneus) Brevis (L4-L5, S1)
Lateral Crural Compartment
PA: Distal 2/3 of the fibula
DA: Lateral base of the 5th metatarsal
A: Ankle plantarflexion & foot eversion
Superficial Fibular N. Innervation
Flexor Digitorum Longus (L5, S1-S2)
Posterior Crural Compartment
PA: Posterior tibia distal to the soleal line
DA: Plantar surface of the distal phalangeal bases
A: Ankle plantarflexion, flexes digits 2-5 (IP & MP)
Tibial N. Innervation
Flexor Hallucis Longus (L5, S1-S2)
Posterior Crural Compartment
PA: Distal 2/3 of the posterior fibular surface & the crural interosseous membrane
DA: Plantar aspect of the distal phalangeal base of the 1st toe
A: Ankle plantarflexion & Great toe flexion (IP & MP)
Tibial N. Innervation
Gastrocnemius (S1-S2)
Posterior Crural Compartment
PA: Posterior aspect of the femoral condyles and joint capsule
DA: Posterior calcaneal surface
A: Knee flexion & ankle plantarflexion
Tibial N. Innervation
Plantaris (L4-5, S1)
Posterior Crural Compartment
PA: Lateral supracondyle line
DA: Posterior calcaneal surface
A: Knee flexion & ankle plantarflexion
Tibial N. Innervation
Popliteus (L4-L5, S1)
Posterior Crural Compartment
PA: Lateral femoral condyle and oblique popliteal ligament
DA: Soleal line of the tibia
A: In non-weight bearing, medial rotation of the tibia & knee flexion; In WB, insertion if fixed so does lateral rotation of the femur & knee flexion from extension into early flexion
Tibial N. Innervation
Soleus (L5, S1-S2)
Posterior Crural Compartment
PA: Posterior aspect of the fibula head & proximal 1/4 of the fibula & tibial soleal line
DA: Posterior calcaneal surface
A: Ankle plantarflexion
Tibial N. Innervation
Tibialis Posterior (L4-L5, S1) (Posterior Crural Compartment)
PA: Crural interosseous membrane, lateral tibial surface & medial fibular surface
DA: Navicular, intermediate cuneiform & base of metatarsals 2-4
A: Ankle plantarflexion & foot inversion
Tibial N. Innervation
Abductor Digiti Minimi (S1-S2)
1st level of plantar feet muscles
PA: Calcaneal tuberosity
DA: Lateral side of proximal phalangeal base of 5th digit
A: 5th digit abduction & flexion
Lateral Plantar N. Innervation
Abductor Hallucis (L4-L5, S1) (1st level of plantar feet muscles)
PA: Medial calcaneal tuberosity
DA: Medial side of the proximal phalangeal base of the great toe
A: Great toe flexion & abduction
Medial Plantar N. Innervation
Adductor Hallucis (S1-S2) (3rd level of plantar feet muscles)
PA: Metatarsals 2-4 bases (oblique head) & distal ends of metatarsals 3-5 (transverse head)
DA: Lateral base of the proximal phalanx of the great toe
A: Great toe adduction
Lateral plantar N. Innervation
Extensor digitorum brevis (L4-L5, S1)
Dorsal foot muscle
PA: Anterolateral calcaneus
DA: Dorsal aspect of the base of the proximal phalanx or the lateral side of tendons of extensor digitorum longus
A: Digits 2-5 extension, 1st digit extension
Deep fibular N. Innervation
Extensor Hallucis Brevis (L4-L5, S1)
Dorsal Foot muscle
PA: Extensor hallucis brevis
DA: Dorsal aspect of the base of the proximal phalanx of the hallux
A: Great toe extension at metatarsophalangeal joint
Deep fibular N. Innervation
Quadratus plantae (S1-S2) (2nd level of plantar feet muscles)
PA: Medial surface of the calcaneus & lateral process of calcaneal tuberosity
DA: Long flexor tendons
A: Assists flexor digitorum longus
Lateral Plantar N. Innervation
Flexor Digitorum Brevis (L4-L5, S1)
1st level of plantar feet muscles
PA: Medial process of calcaneal tuberosity
DA: Sides of intermediate phalanges of digits 2-5
A: Toe flexion (proximal IP)
Medial Plantar N. Innervation
Flexor Digiti Minimi (S1-S2)
3rd level of plantar feet muscles
PA: 5th metatarsal base
DA: proximal phalangeal base
A: 5th digit flexion (MP)
Lateral Plantar N. Innervation
Flexor Hallucis Brevis (L4-L5, S1)
3rd level of plantar feet muscles
PA: Cuboid & tendon of tibialis posterior
DA: Base of the proximal phalanx of the great toe
A: Great toe flexion (MP)
Medial Plantar N. Innervation
Dorsal Interossei (S1-S2) (4th level of plantar feet muscles)
PA: Metatarsal shafts
DA: proximal phalangeal bases & dorsal digital expansions of digits 2-4
A: Digit 2-4 abduction & flexion (MP)
Lateral Plantar N. Innervation
Plantar Interossei (S1-S2) (4th level of plantar feet muscles)
PA: Plantar surface of the base of metatarsals
DA: Dorsal digital expansions of digits 3-5
A: Digits 3-5 adduction & flexion (MP)
Lateral Plantar N. Innervation
Lumbricals(1: L4-L5, S1; 2-4: S1-S2)
2nd level of plantar feet muscles
PA: Tendons of flexor digitorum longus
DA: Medial sides of dorsal expansions of digits 2-5
A: Proximal phalanges flexion (MP) & extends IP joints
1st Lumbrical = Medial Plantar N. Innervation
2nd-4th Lumbricals = Lateral Plantar N. Innervation
