Abductor Hallucis
Origin: Medial process of tuberosity of the calcaneus, flexor retinaculum, plantar aponeurosis, and adjacent intermuscular septum
Insertion: Medial side of base of proximal phalanx of great toe. Some fibers are attached to medial sesamoid bone, and a tendinous slip may extend to base of proximal phalanx of great toe.
Action: Abducts and assists in flexion of the metatarsophalangeal joint of the great toe, and assists with adduction of the forefoot.
Innervation:  Tibial, L4, <strong>5, S1</strong>

Adductor Hallucis
Origin: 
Oblique Head - From bases of second through fourth metatarsal bones and sheath of the tendon of the peroneus longus
Transverse Head - From plantar metatarsophalangeal ligaments of third through fifth digits and deep transverse metatarsal ligament.
Insertion: Lateral side of base of proximal phalanx of great toe
Action: Adducts and assists in flexing the MTP joint of the great toe
Innervation:  Tibial, S1-2

Flexor Hallucis Brevis
Origin: Medial part of the plantar surface of the cuboid bone, adjacent part of the lateral cuneiform bone, and from prolongation of the tendon of the tibialis posterior
Insertion: Medial and lateral sides of the base of the proximal phalanx of the great toe
Action: Flexes the MTP joint of the great toe
Innervation:  Tibial, L4, <strong>5, S1</strong>

Flexor Hallucis Longus
Origin: Posterior surface of distal 2/3 of fibula, interosseous membrane, and adjacent intermuscular septa and fascia
Insertion: Base of distal phalanx of great toe, plantar surface
Action: Flexes IP joint of great toe, assists in flexion of MTP joint, plantarflexion of ankle, and inversion of foot
Innervation: Tibial, L5-S2

Extensor Hallucis Longus
Origin: Middle two quarters of anterior surface of fibula and adjacent interosseous membrane
Insertion: Base of distal phalanx of great toe
Action: Extends MTP and IP joints of the great toe, assists in inversion of the foot and dorsiflexion of the ankle
Innervation: Deep Peroneal, L4, <strong>5, S1</strong>

Extensor Hallucis Brevis
Origin: Distal part of superior and lateral surfaces of calcaneus, lateral talocalcaneal ligament, and apex of inferior extensor retinaculum
Insertion: Dorsal surface of base of proximal phalanx of great toe
Action: Extends MTP joint of the great toe
Innervation: Deep Peroneal, L4, <strong>5, S1</strong>

Lumbricales (4)
Origin: 
1st - Medial side of first flexor digitorum longus tendon
2nd - Adjacent sides of first and second flexor digitorum longus tendons
3rd - Adjacent sides of second and third flexor digitorum longus tendons
4th - Adjacent sides of third and fourth flexor digitorum longus tendons
Insertion: Medial side of proximal phalanx and dorsal expansion of the extensor digitorum longus tendon of the second through fifth digits
Action: Flexes MTP joints and assists in extending IP joints of second through fifth digits
Innervation:
1st - Tibial, L4, <strong>5, S1
</strong>2nd-4th - Tibial, (L4-5), <strong>S1-2</strong>

Plantar Interossei (3)
Origin: Base and medial side of bodies of third through fifth metatarsal bones
Insertion: Medial sides of bases of proximal phalanges of same digit
Action: Adduct the third, fourth, and fifth digits toward the axial line through the second digit. Assist in flexion of the MTP joints, may assist in extension of the IP joints of the 3rd, 4th, and 5th digits.
Innervation:  Tibial, S1-2

Dorsal Interossei (4)
Origin: Each by 2 heads from adjacent sides of metatarsal bones
Insertion: Side of proximal phalanx and capsule of MTP joint
1st - To medial side of 2nd digit
2nd-4th - To lateral side of second through fourth digits
Action: Abducts second through fourth digits from the axial line through the second digit. Assists in flexion of the MTP joints, and may assist in extension of the IP joints, of the second through fourth digits.
Innervation: Tibial, S1-2

Flexor Digitorum Brevis
Origin: Medial process of the tuberosity of the calcaneus, central part of the plantar aponeurosis, and adjacent intermuscular septa
Insertion: Middle phalanx of the second through fifth digits
Action: Flexes the proximal IP joints, and assists in flexion of the MTP joints of the second through fifth digits
Innervation: Tibial, L4, <b>5, S1</b>

Flexor Digitorum Longus
Origin: Middle 3/5 of posterior surface of body of tibia and from fascia covering the tibialis posterior
Insertion: Bases of distal phalanges of second through fifth digits
Action: Flexes PIP and DIP joints of second through fifth digits. Assists in plantarflexion of the ankle joint and inversion of the foot.
Innervation: Tibial, <strong>L5, S1, </strong>(2)

Quadratus Plantae (Flexor Accessorius)
Origin: 
Medial Head - Medial surface of calcaneus and medial border of long plantar ligament
Lateral Head - Lateral border of plantar surface of calcaneus and lateral border of long plantar ligament
Insertion: Lateral margin and dorsal and plantar surfaces of tendon of flexor digitorum longus
Action: Modifies line of pull of the flexor digitorum longus tendons, and assists in flexing the second through fifth digits
Innervation: Tibial, S1-2

Extensor Digitorum Longus
Origin: Lateral condyle of the tibia, proximal 3/4 of the anterior surface of the body of the fibula, proximal part of the interosseous membrane, adjacent intermuscular septa, and deep fascia
Insertion: By four tendons to the second through fifth digits. Each tendon forms and expansion on the dorsal surface of the toe an divides into an intermediate slip attached to the base of the middle phalanx, and into two lateral slips attached to the base of the distal phalanx
Action: Extends the MTP joints, and assists in extending the IP joints of the second through fifth digits. Assists in dorsiflexion of the ankle joint and eversion of the foot
Innervation: Peroneal, L4-S1

Extensor Digitorum Brevis
Origin: Distal part of the superior and lateral surfaces of the calcaneus, lateral talocalcaneal ligament and apex of the inferior extensor retinaculum
Insertion: By four tendons to the first through fourth digits. The most medial slip, aka the Extensor Hallucis Brevis, inserts into the dorsal surface of the base of the proximal phalanx of the great toe. The other three tendons join the lateral sides of the tendons of the extensor digitorum longus to the second, third, and fourth digits.
Action: Extends MTP joints of the first through fourth digits, and assists in extending the IP joints of the second through fourth digits
Innervation: Deep Peroneal, L4, <strong>5, S1</strong>

Peroneus Tertius
Origin: Distal 1/3 of anterior surface of fibula, interosseous membrane, and adjacent intermuscular septum
Insertion: Dorsal surface, base of the fifth metatarsal
Action: Dorsiflexes ankle joint, and everts foot
Innervation: Deep Peroneal, L4-S1

Tibialis Anterior
Origin: Lateral condyle and proximal 1/2 of lateral surface of tibia, interosseous membrane, deep fascia and lateral intermuscular septum
Insertion: Medial and plantar surface of medial cuneiform, base of first metatarsal
Action: Dorsiflexes the ankle, assists in inversion of the foot
Innervation:  Deep Peroneal, <strong>L4, 5, </strong>S1

Tibialis Posterior
Origin: Most of interosseous membrane, lateral portion of the posterior surface of the tibia, proximal 2/3 of medial surface of the fibula, adjacent intermuscular septa and deep fascia
Insertion: Tuberosity of the navicular and by fibrous expansions to the sustentaculum tali, three cuneiforms, cuboid, and bases of second through fourth metatarsal bones
Action: Inverts foot, assists in plantarflexion of ankle
Innervation:  Tibial, L(4), <strong>5, S1</strong>

Peroneus Longus
Origin: Lateral condyle of the tibia, head and proximal 2/3 of the lateral surface of the fibula, intermuscular septa and adjacent deep fascia
Insertion: Lateral side of the base of the first metatarsal and of the medial cuneiform
Action: Everts the foot, assists in plantarflexion of the ankle and depresses the head of the first metatarsal
Innervation: Superficial Peroneal, L4, <strong>5, S1</strong>

Peroneus Brevis
Origin: Distal 2/3 of lateral surface of fibula and adjacent intermuscular septa
Insertion: Tuberosity at the base of the fifth metatarsal, lateral side
Action: Everts the foot, assists in plantarflexion of the ankle
Innervation: Superficial Peroneal, L4, <strong>5, S1</strong>

Soleus
Origin: Posterior surfaces of the head of the fibula and proximal 1/3 of its body, soleal line and middle 1/3 of the medial border of the tibia, and tendinous arch between tibia and fibula
Insertion: With tendon of gastrocnemius into posterior surface of calcaneus
Action: Plantarflexes the ankle joint
Innervation:  Tibial, L5, <strong>S1, 2</strong>

Gastrocnemius
Origin: 
Medial Head - Proximal and posterior part of medial condyle and adjacent part of femur, capsule of knee joint
Lateral Head - Lateral condyle and posterior surface of femur, capsule of knee joint
Insertion: Middle part of posterior surface of calcaneus
Action: Plantarflex the ankle and assist in flexion of the knee
Innervation: Tibial, S1-2

Plantaris
Origin: Distal part of lateral supracondylar line of femur, adjacent part of its popliteal surface and oblique popliteal ligament of knee joint
Insertion: Posterior part of calcaneus
Action: Plantarflex ankle and assist in flexion of the knee
Innervation: Tibial, L4, <strong>5, S1, </strong>(2)

Popliteus
Origin: Anterior part of the groove on the lateral condyle of the femur and oblique popliteal ligament of the knee joint
Insertion: Triangular area proximal to the soleal line on the posterior surface of the tibia and fascia covering the muscle
Action: In nonweight bearing, popliteus medially rotates tibia on femur and flexes the knee joint. In weight bearing, laterally rotates femur on tibia and flexes the knee joint. Helps to reinforce posterior ligaments of the knee joint
Innervation: Tibial, L4, <strong>5, S1</strong>

Semitendinosus
Origin: Tuberosity of the ischium by the tendon common with the long head of the biceps femoris
Insertion: Proximal part of the medial surface of the body of the tibia and deep fascia of the leg
Action: Flexes and medially rotates the knee joint. Extends and assists in medial rotation of the hip joint.
Innervation: Sciatic (Tibial branch), L4, <strong>5, S1-2</strong>

Semimembranosus
Origin: Tuberosity of the ischium, proximal and lateral to the biceps femoris and semitendinosus
Insertion: Posteromedial aspect of medial condyle of tibia
Action: Flexes and medially rotates the knee, extends and assists with medial rotation of the hip
Innervation: Sciatic (Tibial branch), L4, <strong>5, S1-2</strong>

Biceps Femoris
Origin: 
Long Head - Distal part of the sacrotuberous ligament and posterior part of the tuberosity of the ischium
Short Head - Lateral lip of the linea aspera, proximal 2/3 of the supracondylar line, and lateral intermuscular septum
Insertion: Lateral side of the head of the fibula, lateral condyle of the tibia, deep fascia on the lateral side of the leg
Action: Both flex and laterally rotate the knee; long head also extends and assists in lateral rotation of the hip
Innervation: 
Long Head - Sciatic (Tibial branch), L5, <strong>S1, 2, </strong>3
Short Head - Sciatic (Peroneal branch), L5-S2

Rectus Femoris
Origin:
Straight head - From anteroinferior iliac spine
Reflected head - From groove above rim of acetabulum
Insertion: Proximal border of patella and through patellar ligament to tuberosity of tibia
Action: Extends knee, flexes hip
Innervation: Femoral, L2-4

Vastus Lateralis
Origin: Proximal part of the intertrochanteric line, anterior and inferior borders of the greater trochanter, lateral lip of the gluteal tuberosity, proximal half of the lateral lip of linea aspera, and lateral intermuscular septum
Insertion: Proximal border of the patella and through patellar ligament to tuberosity of the tibia
Action: Extends knee
Innervation: Femoral, L2-4

Vastus Intermedius
Origin: Anterior and lateral surfaces of the proximal 2/3 of the body of the femur, distal half of the linea aspera, and lateral intermuscular septum
Insertion: Proximal border of the patella and through the patellar ligament to the tuberosity of the tibia
Action: Extends knee
Innervation: Femoral, L2-4

Vastus Medialis
Origin: Distal half of the intertrochanteric line, medial lip of the linea aspera, proximal part of the medial supracondylar line, tendons of the adductor longus and adductor magnus and medial intermuscular septum
Insertion: Proximal border of the patella and through the patellar ligament to the tuberosity of the tibia
Action: Extends knee
Innervation: Femoral, L2-4

Articularis Genus
May be blended with Vastus Intermedius but is usually distinct
Origin: Anterior surface of distal part of body of femur
Insertion: Proximal part of synovial membrane of knee
Action: Draws the articular capsule proximally
Innervation: Branch of nerve to vastus intermedius (Femoral, L2-4)

Psoas Major
Origin: Ventral surfaces of transverse processes of all lumbar vertebrae, sides of bodies and corresponding intervertebral disks of last thoracic and lal lumbar vertebrae, and membranous arches that extend overs dies of bodies of lumbar vertebrae
Insertion: Lesser trochanter of femur
Action: Flexes hip joint, may assist in lateral rotation and abduction of the hip joint. Acting bilaterally in sitting, it increases lumbar lordosis. Acting unilaterally in sitting, it will assist in lateral ipsilateral trunk flexion
Innervation: Lumbar plexus, L1, <strong>2, 3, </strong>4

Iliacus
Origin: Superior 2/3 of iliac fossa, internal lip of the iliac crest, iliolumbar and ventral sacroiliac ligaments, and ala of the sacrum
Insertion: Lateral side of tendon of the psoas major and just distal to lesser trochanter
Action: Flexes hip joint, may assist in lateral rotation and abduction of the hip joint. Acting bilaterally in sitting, it increases lumbar lordosis. Acting unilaterally in sitting, it will assist in lateral ipsilateral trunk flexion
Innervation: Femoral, L(1), <strong>2, 3, </strong>4

Psoas Minor
Origin: Sides of bodies of 12th thoracic and first lumbar vertebrae and from intervertebral disk between
Insertion: Iliopectineal eminence, arcuate line of ilium, and iliac fascia
Action: Flexion of pelvis on lumbar spine
Innervation: Lumbar plexus, L1-2

Sartorius
Origin: Anterosuperior iliac spine and superior half of notch distal to spine
Insertion: Proximal part of medial surface of tibia near anterior border
Action: Flexes, laterally rotates, and abducts hip; flexes and assists in medial rotation of the knee
Innervation: Femoral, L<strong>2, 3, </strong>(4)

Tensor Fasciae Latae (TFL)
Origin: Anterior part of external lip of iliac crest, outer surface of anterosuperior iliac spine and deep surface of fascia lata
Insertion: Into iliotibial tract of fascia lata at the junction of the proximal and middle thirds of the thigh
Action: Flexes, medially rotates, and abducts the hip; tenses fascia lata; may assist in knee extension
Innervation: Superior gluteal, L4-S1

Pectineus
Origin: Surface of superior ramus of pubis, ventral to pecten, between iliopectineal eminence and pubic tubercle
Insertion: Pectineal line of femur
Action: Adduct hip, flex hip joint
Innervation: Femoral and Obturator, <strong>L2, 3, </strong>4

Adductor Magnus
Origin: Inferior pubic ramus, ramus of ischium (anterior fibers), and ischial tuberosity (posterior fibers)
Insertion: Medial to gluteal tuberosity, middle of linea aspera, medial supracondylar line, an dadductor tubercle of medial condyle of femur
Action: Adduct hip. Anterior fibers may assist in hip flexion; posterior may assist in extension
Innervation: Obturator, L2, 3, 4; Sciatic, L4, 5, S1

Gracilis
Origin: Inferior half of symphysis pubis and medial margin of inferior ramus of pubic bone
Insertion: Medial surface of body of tibia, distal to condyle, proximal to insertion of semitendinosus, and lateral to insertion of sartorius
Action: Adducts hip, flexes and medially rotates knee
Innervation: Obturator, L2-4

Adductor Brevis
Origin: Outer surface of inferior ramus of pubis
Insertion: Distal 2/3 of pectineal line and proximal half of medial lip of the linea aspera
Action: Adduct hip, flex hip
Innervation: Obturator, L2-4

Adductor Longus
Origin: Anterior surface of pubis at junction of crest and symphysis
Insertion: Middle 1/3 of medial lip of linea aspera
Action: Adduct hip, flex hip
Innervation: Obturator, L<strong>2, 3, </strong>4

Piriformis
Origin: Pelvic surface of sacrum between and lateral to first through fourth pelvic sacral foramina, margin of greater sciatic foramen and pelvic surface of sacrotuberous ligament
Insertion: Superior border of greater trochanter
Action: Laterally rotate, may assist in abduction (when flexed) and extension of hip
Innervation: Sacral plexus, L(5), <strong>S1-2</strong>

Quadratus Femoris
Origin: Proximal part of lateral border of tuberosity of ischium
Insertion: Proximal part of quadrate line, extending distally from the intertrochanteric crest
Action: Laterally rotate hip
Innervation: Sacral plexus, <strong>L4-5, S1, </strong>(2)

Obturator Internus
Origin: Internal or pelvic surface of obturator membrane and margin of obturator foramen, pelvic surface of ischium posterior and proximal to obturator foramen, and to a slight extent, obturator fascia
Insertion: Medial surface of greater trochanter of femur, proximal to trochanteric fossa
Action: Laterally rotate, may assist in abduction (when flexed) of hip
Innervation: Sacral plexus, L5-S2

Obturator Externus
Origin: Rami of pubis and ischium, external surface of obturator membrane
Insertion: Trochanteric fossa of femur
Action: Laterally rotate, may assist in adduction of hip
Innervation: Obturator, L3-4

Gemellus Superior
Origin: External surface of spine of ischium
Insertion: With tendon of obturator internus, into medial surface of greater trochanter of femur
Action: Laterally rotate, may assist in abduction (when flexed) of hip
Innervation: Sacral plexus, L5-S2

Gemellus Inferior
Origin: Proximal part of the tuberosity of the ischium
Insertion: With tendon of obturator internus, into medial surface of greater trochanter of femur
Action: Laterally rotate, ma assist in adduction (when flexed) of hip
Innervation: Sacral plexus, <strong>L4-5, S1, </strong>(2)

Gluteus Minimus
Origin: External surface of ilium, between anterior and inferior gluteal lines and margin of greater sciatic notch
Insertion: Anterior border of greater trochanter of femur and hip joint capsule
Action: Abducts, medially rotates, and may assist in flexion of hip
Innervation: Superior Gluteal, L4-S1

Gluteus Medius
Origin: External surface of ilium, between iliac crest and posterior gluteal line dorsally and anterior gluteal line ventrally and gluteal aponeurosis
Insertion: Oblique ridge on lateral surface of greater trochanter of femur
Action: Abducts hip, anterior fibers medially rotate and may assist in flexion of hip joint, posterior fibers laterally rotate and may assist in extension
Innervation: Superior Gluteal, L4-S1

Gluteus Maximus
Origin: Posterior gluteal line of ilium and portion of bone superior and posterior to it, posterior surface of lower part of sacrum, side of coccyx, aponeurosis of erector spinae, sacrotuberous ligament and gluteal aponeurosis
Insertion: Larger proximal portion and superficial fibers of distal portion of muscle into iliotibial tract of fascia lata. Deeper fibers of distal portion into gluteal tuberosity of the femur.
Action: Extends and laterally rotates hip. Lower fibers assist in adduction of hip, upper fibers assist in abduction. Through insertion into iliotibial tract, helps stabilize knee in extension.
Innervation: Inferior Gluteal, L5-S2