Exam 4- lower extremity muscles

Thigh muscles anterior compartment

pectineus

sartorius

quadriceps

• rectus femoris

• vastus lateralis

• vastus intermedius **

• vastus medialis

illiopsoas

• psoas major

• illiacus

thigh muscles medial compartment

“inner thigh”

gracilis

adductor brevis

adductor longus

adductor Magnus

obturator externus

thigh muscles posterior compartment

“hamstrings”

biceps femoris

semitendinosus

semimembranosus

anterior thigh muscles, flexors of hip, and extensors of knee are innervated primarily by ____

femoral nerve

pectineus

origin: pubis

insertion: femur, just inferior to lesser trochanter

innervation: femoral n. L2-L3

action: -adduct and flex thigh

-assist with medial rotation of thigh

illiopsoas

-formed by psoas major and illiacus

-flex thigh (hip flexion)

muscles of quadriceps femoris

4 parts for extending leg at knee joint:

rectus femoris- flex thigh; extend leg at joint

vastus lateralis- extend leg at knee joint

vastus intermedius- extend leg at knee joint

vastus medialis- extend leg at knee joint

Psoas Major

origin: T12-L5

insertion: lesser trochanter of femur

innervation: anterior rami of lumbar nerves L1-L3

action: -flex thigh/hip

-lateral flexion of vertebrae column

-when sitting- flexes trunk

Illiacus

origin: iliac crest and sacrum

insertion: lesser trochanter of femur

innervation: femoral n. (L2-L4)

action: -flex thigh at hip joint

-stabilize hip joint

sartorius

longest muscle in the body; “tailor’s muscle”; crosses two joints (hip & knee)

origin: asis of ilium

insertion: superior part of medial surface of tibia

innervation: femoral n. L2-L3

action: -flex, abduct, and laterally rotate thigh at hip joints

-flex leg at knee joint

quadricep muscle origins

rectus femoris- anterior inferior iliac spine and ilium superior to acetabulum

vastus lateralis- greater trochanter of femur

vastus medialis- medial proximal shaft of femur

vastus intermedius- anterior and lethal surfaces of shaft of femur

quadricep muscles innervation

femoral n L2-L4

Which quad muscle steadies hip joint and helps iliopsoas flex thigh?

rectus femoris

which quad muscle is crucial for walking, running, jumping, and squatting?

rectus femoris

Which muscles are collectively the most powerful muscle in the body?

quadricep muscles

Quadricep muscles insertion

attaches to superior region of patella with rectus femoris tendon, which then attaches to tibial tuberosity distally as the patellar tendon

Medial compartment of thigh is primarily innervated by ______

obturator nerve

Gracilis

most superficial muscle on medial thigh

origin: body and inferior ramus of pubis

insertion: superior part of medial surface of tibia

innervation: anterior branch of obturator nerve L2-L3

action: -adduct thigh

-flex hip

-medially rotate leg

adductor longus

origin: pubis

insertion: middle femur

innervation: branch of obturator n. L2-L4

action: adduct thigh

adductor brevis

origin: pubis

insertion: femur

innervation: obturator nerve, L2-L4

action: -adduct thigh

-some extend flexes thigh

adductor magnus

origin: -pubis: adductor portion

-ischial tuberosity: hamstring portion

insertion: femur

innervation: -obturator n: adductor portion

-tibial n: hamstring portion

action: -adduct thigh (adductor portion)

-extend thigh (hamstring portion)

Femoral triangle boundaries

inguinal ligament superiorly forms base

sartorius m. laterally

adductor longus m. medially

superficial gluteal muscles

large muscles

-gluteus maximus: extension, lateral rotation of thigh

-gluteus medius: abduct, medially rotate thigh

-gluteus minimus: abduct, medially rotate thigh

-tensor fasciae latae: flexor of thigh, not independent

deep gluteal muscles

small muscles; lateral rotators of thigh and stabilizers of hip joints

-piriformis

-obturator internus

-superior gemelli

-inferior gemelli

-quadratus femoris

gluteus maximus

origin: ilium, sacrum and coccyx

insertion: most fibers end in iliotibial tract which inserts into lateral condyle of tibia, some fibers insert on gluteal tuberosity of femur

innervation: inferior gluteal nerve (L5-S2)

action:- major extensor of thigh

- lateral (external) rotator of thigh

- steadies thigh and assists in rising from sitting position

gluteus medius

origin: ilium

insertion: greater trochanter of femur

innervation: superior gluteal nerve (L4-S1)

action: -abduct thigh

-medial rotation of thigh

-prevent pelvis tilt when walking

gluteus minimus

origin: ilium

insertion: greater trochanter of femur

innervation: superior gluteal nerve (L4-S1)

action: -abduct thigh

-medial rotation of thigh

-assist gluteus medius in it’s actions (prevent pelvis tilt when walking)

Tensor Fascia Lata m.

origin: ASIS and anterior part of iliac crest

insertion: iliotibial tract/band (ITB), which attaches to lateral condyle of tibia

innervation: superior gluteal nerve (L4-S1)

action: flexion of thigh

Pririformis m.

origin: 2nd-4th sacrum

insertion: greater trochanter of femur

innervation: branches of anterior rami of sacral nerve (S1-S2)

action: -lateral rotation of extended tigh

-abduct flexed thigh

-steady femoral head in acetabulum (stabilizes hip joint)

Obturator internus

origin: ilium and ischium

insertion: greater trochanter of femur

innervation: nerve to obturator internus (L5-S1)

action: -abduct thigh

-lateral rotation of thigh

-stabilize hip while walking

Superior Gemellus

origin: spine of ischium

insertion: medial surface of greater trochanter of femur

innervation: nerve to obturator internus (L5-S1)

action: -laterally rotates extended thigh

-abduct flexed thigh

-steady femoral head in acetabulum

inferior gemellus

origin: ischial tuberosity

insertion: medial surface of greater trochanter of femur

innervation: nerve to quadratus femoris (L5-S1)

action: -laterally rotates extended thigh

-abduct flexed thigh

-steady femoral head in acetabulum

hamstring muscles

semitendinosus- extend thigh, flex/medially rotate leg

semimembranosus- extend thigh, flex/medially rotate leg

biceps femoris-

• long head: flex and laterally rotate leg when knee is flexed

• short head: flex and laterally rotate leg when knee is flexed

Semitendinosus

origin: ischial tuberosity (ischium)

insertion: medial superior part of tibia

innervation: tibial division of sciatic nerve (L5-S2)

action: -extend thigh

-knee flexion

-medially rotate leg when knee is flexed

-extend trunk when thigh and leg are flexed

semimembranosus

origin: ischial tuberosity

insertion: posterior medial condyle of tibia

innervation: tibial division of sciatica nerve (L5-S2)

action: -extend thigh

-knee flexion

-medially rotate leg when knee is flexed

-extend trunk when thigh and leg are flexed

Biceps femoris long head

origin: ischial tuberosity

insertion: lateral side of head of fibula

innervation: tibial division of sciatic nerve (L5-S2)

action: -flex knee

-lateral rotation when knee is flexed

-extend thigh when starting to walk

biceps femoris short head

origin: lateral femur

insertion: lateral side of head of fibula

innervation: common fibular division of sciatic nerve (L5-S2)

action: -flex knee

-laterally rotate leg when knee is flexed

-extend thigh when starting to walk

Popliteal Fossa Boundaries

superior: biceps femoris (superior lateral), semimembranosus and semitendinosus (superior medial)

inferior: gastrocnemius (inferolateral and inferomedial)

muscles of anterior compartment of leg (dorsiflexor/extensor)

tibialis anterior: dorsiflex ankle, invert foot, support arch of foot longitudinally

extensor digitorum longus: extend lateral 4 digits, dorsiflex ankle

extensor hallucis longus: extend great toe, dorsiflex ankle

peroneus (fibularis) Tertius: dorsiflex ankle, everts foot

Tibialis anterior

origin: lateral condyle and superior ½ of lateral surface of tibia

insertion: medial and inferior surfaces of medial cuneiform and base of first metatarsal

innervation: deep fibular nerve (L4-L5)

action: dorsiflex and invert the foot

extensor digitorum longus

origin: lateral condyle of tibia

insertion: middle and distal phalanges of lateral 4 digits

innervation: deep fibular nerve (L4-L5)

action: extension of toes and ankle

extensor hallucis longus

origin: middle part of anterior surface of fibula

insertion:dorsal aspect of base of distal phalanx of first digit (great toe)

innervation: deep fibular nerve (L4-L5)

action: extend great toe and dorsiflexion of foot at ankle

peroneus (fibularis) Tertius m.

origin: inferior 1/3 of anterior surface of fibula

insertion: dorsum of base of 5th metatarsal

innervation: deep fibular nerve (L5-S1)

action: dorsiflex and evert foot

muscles of lateral compartment of leg (everter)

peroneus (fibularis) longus: evert foot, plantar flex ankle, support arch of foot transversely

peroneus (fibularis) brevis: evert foot

peroneus (fibularis) longus m.

origin: head and superior 2/3 of lateral surface of fibula

insertion: base of first metatarsal & medial cuneiform

innervation: superficial fibular nerve (L5-S2)

action: evert foot, weakly plantar flex ankle, supports transverse arch of foot

peroneus (fibularis) brevis

origin: inferior 2/3 of lateral surface of fibula

insertion: dorsal surface of tuberosity of base of fifth metatarsal

innervation: superficial fibular nerve (L5-S2)

action: evert foot, weakly plantar flex ankle

muscles of posterior compartment of leg - superficial

(supplied by tibial nerve and posterior tibial and fibular vessels)

gastrocnemius: plantar flex ankle/foot when knee extended, raise heel while walking, flex leg at knee joint

soleus: plantar flex foot, steadies leg on foot

plantaris: plantar flex foot

muscles of posterior compartment of leg - deep

popliteus: flex knee

flexor hallucis longus: flex great toe, plantar flex foot, longitudinal arch support

flexor digitorum longus: flexes lateral 4 digits, plantar flex foot, longitudinal arch support

tibialis posterior: plantar flex foot, invert foot, medial longitudinal arch support

Gastrocnemius

origin: lateral condyle and medial condyle of femur

insertion: posterior surface of calcaneus via achilles tendon

innervation: tibial nerve (S1-S2)

action: plantar flex ankle when knee is extended, raises heel during walking and flex leg at knee joint

Soleus

deep to gastrocnemius; is “workhouse” of plantarflexion

origin: head of fibula and medial border of tibia

insertion: posterior surface of calcaneus via Achilles tendon

innervation: tibial nerve (S1-S2)

action: plantarflexes ankle

Plantaris

origin: lateral supracondylar of femur

insertion: calcaneus via calcaneal tendon

innervation: tibial nerve (S1-S2)

action: weakly assists gastrocnemius in plantarflexing ankle

tibialis posterior

deepest, most medial

origin: posterior tibia and posterior fibula

insertion: navicular, cuneiforms, cuboid and bases of 2nd-4th metatarsals

innervation: tibial nerve (L4-L5)

action: plantar flexes ankle, inverts foot, supports medial longitudinal arch of foot

popliteus

origin: lateral femoral condyle and lateral meniscus

insertion: posterior surface of tibia

innervation: tibial nerve (L4-S1)

action: -flex knee

-laterally rotating femur on fixed tibia

-medially rotating tibia of unplanted limb

flexor hallucis longus

“push off muscle”

origin: posterior fibula

insertion: base of distal phalanx of great toe

innervation: tibial nerve (S2-S3)

action: -flex great toe at all joints

-plantarflex ankle

-support medial longitudinal arch of foot

flexor digitorum longus

origin: medial posterior tibia

insertion: bases of distal phalanges of lateral 4 digits

innervation: tibial nerve (S2-S3)

action: -flex lateral 4 digits

-plantarflex ankle

-support longitudinal arch of foot

foot muscles: plantar interossei (3 muscles)

adducts digits 3-5, flex MTPs

foot muscles: dorsal interossei (4 muscles)

abduct digits 2-4, flex MTPs

extensor digitorum brevis (foot)

origin: calcaneus

insertion:toes

innervation: peroneal nerve

action: extends digits 2-4

extensor hallucis brevis (foot)

origin: calcaneus

insertion: phalanx of 1st digit

innervation: peroneal nerve

action: extend 1st digit

musles of ankle inversion

tibialis anterior

tibialis posterior

(occurs at subtalar joint)

muscles of ankle eversion

peroneus longus

peroneus brevis