Pelvis and Lower Extremity Muscles Flashcards
obturator internus origin
Pelvic surfaces of the ilium and ischium; obturator membrane
obturator internus insertion
greater trochanter of the femur
obturator internus innervation
nerve to obturator internus (L5, S1, S2)
obturator internus action
external rotation of thigh; assists in holding the head of the femur in acetabulum
piriformis origin
pelvic surface of the sacrum
piriformis insertion
greater trochanter of the femur
piriformis innervation
Nerve to Piriformis (S1-S2)
piriformis action
external rotation; abducts the thigh; assists in holding the head of the femur in acetabulum
Coccygeus origin
ischial spine
coccygeus insertion
inferior end of the sacrum and superior region of coccyx
coccygeus innervation
branches of S4 and S5 spinal nerves
coccygeus action
forms small part of pelvic diaphragm that supports pelvic viscera; flexes coccyx
Levator ani origin
body of pubis; tendinous arch of obturator fascia; ischial spine
levator ani insertion
Perineal body; coccyx; anococcygeal ligament; walls of the prostate or vagina, rectum, and anal canal
levator ani innervation
Nerve to levator ani (branches of S4), inferior anal (rectal) nerve, and coccygeal plexus
levator ani action
Forms most of pelvic diaphragm that helps support pelvic viscera and resists increases in
intra-abdominal pressure
Psoas major origin
Transverse processes of lumbar vertebrae; sides of bodies of T12-L5 vertebrae and intervening intervertebral discs
psoas major insertion
lesser trochanter of femur
psoas major innervation
Femoral nerve (L2-L3)
psoas major action
Acting inferiorly with iliacus, it flexes the thigh; acting superiorly, it flexes the vertebral column laterally; it is used to balance the trunk; when sitting, it acts inferiorly with the iliacus to flex the trunk
Iliacus origin
iliac fossa and crest; the ala of the sacrum
Iliacus insertion
lesser trochanter of femur and shaft inferior to it and to psoas major tendon
Iliacus innervation
femoral nerve (L2-L4)
Iliacus action
flexes thigh and stabilizes hip joint; acts with psoas major
Quadratus Lumborum origin
medial half of inferior border of 12th ribs and tips of lumbar transverse processes
quadratus lumborum insertion
iliolumbar ligament and internal lip of iliac crest
quadratus lumborum innervation
anterior branches of T12 and L1-L4 nerves
quadratus lumborum action
extends and laterally flexes vertebral column; fixes 12th rib during inspiration
Pectineus origin
superior ramus of pubis
pectineus insertion
pectineal line of femur, just inferior to lesser trochanter
pectineus innervation
femoral nerve (L2, L3); may receive a branch from obturator nerve
pectineus action
adducts and flexes thigh; assists with medial rotation of thigh
psoas minor origin
sides of T12-L1 vertebrae and intervertebral discs
psoas minor insertion
pectineal line and iliopubic eminence via iliopectineal arch
psoas minor innervation
Femoral nerve (L2-L3)
psoas minor action
Act conjointly in flexing thigh at hip joint and in stabilizing this joint
Sartorius origin
anterior superior iliac spine and superior part of notch inferior to it
Sartorius insertion
superior part of medial surface of tibia
Sartorius innervation
femoral nerve (L2, L3)
sartorius action
Flexes, abducts, and externally rotates thigh at hip joint; flexes leg at knee joint, (medially rotating leg when knee is flexed)
rectus femoris origin
Anterior inferior iliac spine and ilium superior to acetabulum
rectus femoris insertion
base of the patella and to tibial tuberosity via patellar ligament
rectus femoris innervation
femoral nerve (L2, L3, L4)
rectus femoris action
extend leg at knee joint; rectus femoris also steadies hip joint and helps iliopsoas flex thigh
vastus lateralis origin
greater trochanter and lateral lip of linea aspera of femur
vastus lateralis insertion
base of the patella and to tibial tuberosity via patellar ligament
vastus lateralis innervation
femoral nerve (L2, L3, L4)
vastus lateralis action
extend leg at knee joint
vastus medialis origin
intertrochanteric line and medial lip of linea aspera of femur
vastus medialis insertion
the patella and the tibial tuberosity via the patellar ligament
vastus medialis innervation
femoral nerve (L2, L3, L4)
vastus medialis action
extend leg at knee joint
vastus intermedius origin
anterior and lateral surfaces of shaft of femur
vastus intermedius insertion
base of the patella and to tibial tuberosity via patellar ligament
vastus intermedius innervation
femoral nerve (L2, L3, L4)
vastus intermedius action
extend leg at knee joint
adductor longus origin
medial part of the superior ramus of the pubis
adductor longus insertion
middle third of linea aspera of femur
adductor longus innervation
obturator nerve and branch of anterior division (L2, L3, L4)
adductor longus action
adducts thigh
adductor brevis origin
body and inferior ramus of pubis
adductor brevis insertion
pectineal line and proximal part of linea aspera of femur
adductor brevis innervation
obturator nerve and branch of anterior division (L2, L3, L4)
adductor brevis action
adducts thigh; to some extent flexes it
adductor Magnus (adductor part) origin
inferior ramus of pubis and ramus of ischium, ischial tuberosity
adductor Magnus (adductor part) insertion
medial lip of linea aspera and the adductor tubercle of the femur
adductor magnus (adductor part) innervation
obturator nerve (L2, L3, L4) and branches of posterior division
adductor magnus (adductor part) action
adducts thigh; adductor part flexes thigh
adductor Magnus (hamstring part) origin
ischial tuberosity
adductor Magnus (hamstring part) insertion
adductor tubercle of femur
adductor Magnus (hamstring part) innervation
tibial part of sciatic nerve (L4)
adductor Magnus (hamstring part) action
adducts thigh; hamstring part extends thigh
gracilis origin
body and inferior ramus of pubis
gracilis insertion
superior part of medial surface of tibia
gracilis innervation
obturator nerve (L2, L3)
gracilis action
adducts thigh; flexes leg; internal rotation
obturator externus origin
margins of obturator foramen and obturator membrane
obturator externus insertion
trochanteric fossa of femur
obturator externus innervation
obturator nerve (L3, L4)
obturator externus action
external rotation of thigh; steadies head of femur in acetabulum
gluteus maximus origin
Ilium posterior to posterior gluteal line; dorsal surface of sacrum and coccyx; sacrotuberous ligament
gluteus maximus insertion
upper fibers: the posterior part of the iliotibial tract and the fasciae latae muscles
lower fibers: the gluteal tuberosity of the proximal femur
gluteus maximus innervation
inferior gluteal nerve (L5, S1, S2)
gluteus maximus action
Extends thigh (especially from flexed position) and assists in its external rotation; steadies thigh and assists in rising from sitting position
gluteus medius origin
External surface of ilium between anterior and posterior gluteal lines
gluteus medius insertion
lateral surface of greater trochanter of femur
gluteus medius innervation
superior gluteal nerve (L5, S1)
gluteus medius action
Abduct and medially rotate thigh; keep pelvis level when ipsilateral limb is weight bearing and advance opposite (unsupported side
during its swing phase
gluteus minimus origin
External surface of ilium between anterior and inferior gluteal lines
gluteus minimus insertion
anterior surface of greater trochanter of femur
gluteus minimus innervation
superior gluteal nerve (L5, S1)
gluteus minimus action
Abduct and medially rotate thigh; keep pelvis level when ipsilateral limb is weight bearing and advance opposite (unsupported side
during its swing phase
tensor fasciae latae origin
anterior superior iliac spine; anterior part of iliac crest
tensor fasciae latae insertion
iliotibial tract
tensor fasciae latae innervation
superior gluteal nerve (L5, S1)
tensor fasciae latae action
abduction, flexion, and internal rotation at the hip joint
superior and inferior gemelli origin
Superior: Ischial spine
Inferior: ischial tuberosity
superior and inferior gemelli insertion
medial surface of greater trochanter (trochanteric fossa) of femur
superior and inferior gemelli innervation
Superior gemellus: Nerve to obturator internus (L5, S1)
Inferior gemellus: Nerve to quadratus femoris (L5, S1)
Superior and inferior gemelli action
externally rotate extended thigh and abduct flexed thigh; steady femoral head in acetabulum
quadratus femoris origin
lateral border of ischial tuberosity
quadratus femoris insertion
quadrate tubercle on intertrochanteric crest of femur and area inferior to it
quadratus femoris innervation
nerve to quadratus femoris (L5, S1)
quadratus femoris action
laterally rotates thigh; steadies femoral head in acetabulum
semitendinosus origin
Ischial tuberosity
semitendinosus insertion
medial surface of tibial tuberosity
semitendinosus innervation
tibial division of sciatic nerve part of tibia (L5, S1, S2)
semitendinosus action
Extend thigh; flex leg and rotate it medially when knee is flexed. When thigh and leg are flexed, these muscles can extend trunk.
semimembranosus origin
ischial tuberosity
semimembranosus insertion
medial tibial condyle, the oblique popliteal ligament, the popliteal fascia
semimembranosus innervation
tibial division of sciatic nerve part of tibia (L5, S1, S2)
semimembranosus action
Extend thigh; flex leg and rotate it internally when knee is flexed. When thigh and leg are flexed, these muscles can extend trunk.
biceps femoris origin
Long head: ischial tuberosity
Short head: linea aspera and lateral supracondylar line of femur
biceps femoris insertion
Lateral side of head of fibula
biceps femoris innervation
Long head: tibial nerve (L5-S2)
Short head: common fibular nerve (L5-S2)
biceps femoris action
Flexes leg and rotates it externally when knee is flexed; extends thigh (e.g., accelerating mass during first step of gait)
Tibialis anterior origin
lateral condyle and superior half of lateral surface of tibia and interosseous membrane
tibialis anterior insertion
medial cuneiform and base of 1st metatarsal
tibialis anterior innervation
deep fibular nerve (L4, L5)
tibialis anterior action
dorsiflexes ankle and inverts foot
extensor digitorum longus origin
Lateral condyle of tibia and superior three quarters of medial surface of fibula and interosseous membrane
extensor digitorum longus insertion
middle and distal phalanges of lateral four digits
extensor digitorum longus innervation
deep fibular nerve (L4, L5)
extensor digitorum longus action
extends lateral four digits and dorsiflexes ankle
extensor hallucis longus origin
middle part of anterior surface of fibula and interosseous membrane
extensor hallucis longus insertion
dorsal aspect of base of distal phalanx of great toe (hallux)
extensor hallucis longus innervation
deep fibular nerve (L4, L5)
extensor hallucis longus action
extends great toe and dorsiflexes ankle
Fibularis tertius origin
Inferior third of anterior surface of
fibula and interosseous membrane
Fibularis tertius insertion
dorsum of base of 5th metatarsal
Fibularis tertius innervation
deep fibular nerve (L4, L5)
Fibularis tertius action
dorsiflexes ankle and aids in eversion of foot
fibularis longus origin
head and superior two thirds of lateral surface of fibula
fibularis longus insertion
base of 1st metatarsal and medial cuneiform
fibularis longus innervation
Superficial fibular nerve (L5, S1, S2)
fibularis longus action
everts foot and weakly plantarflexes ankle
fibularis brevis origin
inferior two thirds of lateral surface of fibula
fibularis brevis insertion
dorsal surface of tuberosity on lateral side of base of 5th metatarsal
fibularis brevis innervation
Superficial fibular nerve (L5, S1, S2)
fibularis brevis action
everts foot and weakly plantarflexes ankle
Gastrocnemius origin
lateral head: lateral aspect of lateral condyle of femur
Medial head: popliteal surface of femur; superior to medial condyle
Gastrocnemius insertion
posterior surface of calcaneus via calcanea tendon
gastrocnemius innervation
tibial nerve (S1, S2)
gastrocnemius action
Plantarflexes ankle when the knee is extended; raises heel during walking; flexes leg at knee joint
soleus origin
posterior surface of the proximal fibula and the soleal line of the tibia
soleus insertion
posterior surface of calcaneus via calcanea tendon
soleus innervation
tibial nerve (S1, S2)
soleus action
plantarflexes ankle independent of position of knee; steadies leg on foot
plantaris origin
Inferior end of lateral supracondylar line of femur; oblique popliteal ligament
plantaris insertion
posterior surface of calcaneus via calcanea tendon
plantaris innervation
tibial nerve (S1, S2)
plantaris action
flexion of the knee and plantar flexion of the foot
Popliteus origin
lateral condyle of femur and lateral meniscus
popliteus insertion
posterior surface of tibia and superior to soleal line
popliteus innervation
tibial nerve (L4, L5, S1)
popliteus action
weakly flexes knee and unlocks it by rotating femur on fixed tibia
flexor hallucis longus origin
Inferior 2/3 of posterior surface of fibula; inferior part of interosseous membrane
flexor hallucis longus insertion
base of distal phalanx of great toe (hallux)
flexor hallucis longus innervation
Tibial nerve (S2, S3)
flexor hallucis longus action
Flexes great toe at all joints; weakly plantarflexes ankle, supports medial longitudinal arch of foot
flexor digitorum longus origin
middle third of the posterior surface of the tibia
flexor digitorum longus insertion
bases of distal phalanges of lateral 4 digits
flexor digitorum longus innervation
tibial nerve (S2, S3)
flexor digitorum longus action
flexes lateral four digits, plantarflexes ankle, supports longitudinal arches of foot
tibialis posterior origin
Interosseous membrane; posterior surface of tibia inferior to soleal line; posterior surface of fibula
tibialis posterior insertion
Tuberosity of navicular, medial cuneiform, cuboid, and sustentaculum tali of calcaneus; bases of 2nd, 3rd, and 4th metatarsals
tibialis posterior innervation
tibial nerve (L4, L5)
tibialis posterior action
plantarflexes ankle, inverts foot