lower limb muscles

innervation of the lower limb

composed of ventral rami (hypaxial muscles)

innervated by the lumbosacral plexus (L1-S4)-combo of lumbar and sacral plexuses

lumbosacral trunk is the nerve bundle connecting the two plexuses

obturator nerve

major nerve innervating muscles of the medial thigh, goes through obturator foramen of pelvis

femoral nerve

innervates the anterior thigh muscles

sciatic nerve

is the longest and thickest nerve in the body in the posterior thigh, is tibial and common fibular nerves bound together (goes through greater sciatic foramen)

tibial nerve

innervates posterior thigh muscles, posterior leg and sole of foot

common fibular nerve

innervates below the knee laterally, and also anteriorly splits into deep fibular (front) and superficial fibular (lateral) and innervates dorsal part of the foot

muscles of the hip

iliopsoas

gluteus maximus

lesser gluteals

tensor fasciae latae

small lateral rotators of hip

all insert on the proximal femur

iliopsoas

hip muscle combines iliacus (blade) and psoas major from lumbar vetebrae, origin is iliac blade and transverse processes of vertebrae, inserts on lesser trocanter of femur

flexes the thigh

innervated by the femoral nerve

gluteus maximus

largest buttock muscle that comes from the iliac blade and sacrum, insertion is the posterolateral femur

extends the hip and thigh but is only used for powerful movements, keeps you upright when walking and most active when your foot hits the ground

gluteus medius

hip muscle on top of minimus, comes from iliac blade and inserts on greater trocanter of the femur

abducts the hip to keep you from falling on your unsupported side while resisted adduction of the supported side

tensor fasciae latae

hip muscle on the lateral side of the hip, origin is anterior inferior iliac spine and insertion is iliotibial tract (CT)

abducts the thigh (no important role)

small lateral rotators of the hip

six small hip muscles deep in the posterior hip that insert on the posterolateral femur, origin is pelvis

all laterally rotate

anterior muscles of the thigh

are innervated by the femoral nerve

quadriceps femoris

sartorius

quadriceps femoris

has 4 heads, middle is rectus femoris, has vastus lateralis and vastus medialis, vastus intermedius is deep to rectus femoris

all insert on the patella

only extensor of the knee

vastus muscles originate from the anterior part of the proximal femur, rectus femoris originates from the anterior inferior iliac spine (only part crossing hip)-can flex thigh and extend knee at the same time

quadriceps is at an angle so it is more prone to injury

sartorius

anterior thigh muscle innervated by the femoral nerve

origin is anterior superior iliac spine, and goes from lateral to medial side of tibia crossing hip and knee

flexes, abducts, and laterally rotates thigh

can flex the knee as well

posterior thigh muscles

innervated by tibial nerve

has three hamstring muscles that originate from the ischial tuberosity

semitendinosus and semimembranosus-tibia

biceps femoris-fibula

all extend the hip and flex the knee

lateral thigh muscles

innervated by the common fibular nerve

biceps femoris (short head)- not a hamstring because it doesnt have an origin of the ischial tuberosity- instead is posterior femur

is not innervated by the tibial nerve, has no hip action

pure hip flexor

medial thigh muscles

all have an origin off the pubis, all adduct the thigh/hip and are mostly innervated by the obturator nerve

gracilis

pectineus

adductor brevis

adductor longus

adductor magnus

gracilis

medial thigh muscle on medial part of thigh that inserts on the proximal tibia and inserts on the pubis

adducts thigh

innervated by obturator nerve

pectineus

medial thigh muscle that inserts on the femoral shaft posteriorly and originates from the pubis

innervated by the femoral nerve

flexes and adducts the thigh

adductor brevis & longus

originates from the pubis, inserts on the femur

adducts the thigh/hip

adductor magnus

originates from the pubis, inserts on the femur

is two separate muscles in animals

“adductor” part has origin on pubis and is innervated by the obturator nerve, the hamstring part has ischium origin and is innervated by the tibial nerve

dorsiflexion

lifting the foot so the superior surface approaches the leg

plantarflexion

pointing the toes

inversion

turning soles medially

eversion

turning soles laterally

lateral muscles of the leg

innervated by the superficial fibular nerve

origin is fibula

fibularis longus- crosses medially to insert on m1

fibularis brevis-runs laterally to insert on base of m5

evert the foot and also plantarflexors (required to shift weight medially when walking

anterior muscles of the leg

all have origin from the proximal tibia or fibula, all pass anteriorly to the ankle joint, innervated by the deep fibular nerve

all dorsifllexors

tibialis anterior

extensor digitorum longus

etensor hallucis longus