Muscles of the Trunk and Lower Limbs

What muscle is this? (superficial)

external intercostals

What is the action of the external intercostals?

elevates ribs during normal inspiration

What is this muscle? (deep)

internal intercostals

What is the action of the internal intercostals?

depresses ribs during forced exhalation

What muscle is this?

diaphragm

What is the action of the diaphragm?

expands the thoracic cavity during normal inspiration

What muscle is this?

external oblique

What is the action of the external oblique?

both sides compress the abdominal wall

What muscle is this?

internal oblique

What is the action of the internal oblique?

both sides compress the abdominal wall

What muscle is this?

transversus abdominus

What is the action of the transversus abdominis?

both sides compress the abdominal wall

What muscle is this?

rectus abdominis

What is the action of the rectus abdominis?

compresses the abdominal wall

What is the associated structure that is formed by the aponeurosis of the external oblique (also contains tissues coursing from the trunk to the lower limb)?

inguinal ligament

What is the associated structure that is connective tissue connecting left and right rectus abdominis muscles?

linea alba

What muscle is this? (superficial/midline)

rectus femoris

What is the origin of the rectus femoris?

anterior inferior iliac spine of the ilium

What is the common insertion for the quadriceps femoris group?

patella via the quadriceps tendon, tibial tuberosity of the tibia via the patellar ligament

What is the common action of the quadriceps femoris group?

extends the leg

Which muscle of the quadriceps femoris group is lateral?

vastus lateralis

What muscle of the quadriceps femoris group is medial?

vastus medialis

What muscle of the quadriceps femoris group is deep/in the midline?

vatus intermedius

What muscle is this? (most anterior)

sartorius

What is the origin of the sartorius?

anterior superior iliac spine of the ilium

What is the insertion of the sartorius?

tibial tuberosity, medial side via the pes anserinus tendon

What is the action of the sartorius?

flexes the leg

What forms the iliopsoas group?

iliacus, psoas major

What muscle is this?

iliacus

What is the origin of the iliacus?

iliac fossa of the ilium

What muscle is this?

psoas major

What is the origin of the psoas major?

T12-L5 vertebrae

What is the common insertion of the iliopsoas group?

lesser trochanter of the femur

What is the common action of the iliopsoas group?

flexes the thigh

What muscle is this?

pectineus

What is the action of the pectineus?

adducts the thigh

What muscle is this? (next going medially)

adductor longus

What is the action of the adductor longus?

adducts the thigh

What muscle is this? (deep)

adductor brevis

What is the action of the adductor brevis?

adducts the thigh

What muscle is this?

adductor magnus

What is the action of the adductor magnus?

adducts the thigh

What muscle is this?

gracilis

What is the origin of the gracilis?

inferior ramus and body of the pubis

What is the insertion of the gracilis?

proximal medial surface of the tibia via the pes anserinus tendon

What is the action of the gracilis?

weakly adducts the thigh

What muscle of the hamstrings group is this? (lateral)

semitendinosus

What is the origin of the semitendinosus?

ischial tuberosity of the ischium

What is insertion of the semitendinosus?

proximal medial surface of the tibia via the pes anserinus tendon

What is the action of the semitendinosus?

flexes the leg

What muscle of the hamstrings group is this? (most medial)

semimembranosus

What is the origin of the semimembranosus?

ischial tuberosity of the ischium

What is the insertion of the semimembranosus?

medial condyle of the tibia

What is the action of the semimembranosus?

flexes the leg

What muscle is this?

biceps femoris long head

What is the origin of the biceps femoris long head?

ischial tuberosity of the ischium

What is the insertion of the biceps femoris long head?

head of the fibula, lateral condyle of the tibia

What is the action of the biceps femoris long head?

flexes the leg

What muscle is this?

biceps femoris short head

What is the origin of the biceps femoris short head?

linea aspera of the femur

What is the insertion of the biceps femoris short head?

head of the fibula, lateral condyle of the tibia

What is the action of the biceps femoris short head?

flexes the leg

What muscle is this?

tensor fasciae latae

What is the origin of the tensor fasciae latae?

iliac crest and anterior superior iliac spine of the ilium

What is the insertion of the tensor fascia latae?

iliotibial tract

What is the action of the tensor fasciae latae?

medially rotates the thigh

What muscle is this? (superficial)

gluteus maximus

What is the origin of the gluteus maximus?

iliac crest of the ilium, sacrum, coccyx

What is the insertion of the gluteus maximus?

iliotibial tract, linea aspera of the femur, gluteal tuberosity of the femur

What is the action of the gluteus maximus?

laterally rotates the thigh

What muscle is this? (superior/medial)

gluteus medius

What is the origin of the gluteus medius?

iliac crest of the ilium

What is the insertion of the gluteus medius?

greater trochanter of the femur

What is the action of the gluteus medius?

medially rotates the thigh

What muscle is this? (deepest)

gluetus minimus

What is the origin of the gluteus minimus?

lateral surface of the ilium

What is the insertion of the gluteus minimus?

greater trochanter of the femur?

What is the action of the gluteus minimus?

medially rotates the thigh

What muscle is this? (most medial/deep)

piriformis

What is the origin of the piriformis?

anterolateral surface of the sacrum

What is the insertion of the piriformis?

greater trochanter of the femur

What is the action of the piriformis?

laterally rotates the thigh

What is the associated structure that is a thick band of fascia continuous with the tensor fasciae latae?

iliotibial tract

What muscle is this?

tibialis anterior

What is the origin of the tibialis anterior?

lateral condyle and proximal shaft of the tibia

What is the insertion of the tibialis anterior?

metatarsal I, medial cuneiform bone

What is the action of the tibialis anterior?

dorsiflexes the foot

What muscle is this?

extensor hallucis longus

What is the action of the extensor hallucis longus?

dorsiflexes the foot

What muscle is this?

extensor digitorum longus

What is the action of the extensor digitorum longus?

dorsiflexes the foot

What muscle is this? (superficial)

fibularis longus

What is the action of the fibularis longus?

weakly plantar flexes the foot

What muscle is this? (deep)

fibularis brevis

What is the action of the fibularis brevis?

weakly plantar flexes the foot

What muscle is this? (superficial)

gastrocnemius

What is the origin of the gastrocnemius?

lateral and medial condyles of the femur

What is the insertion of the gastrocnemius?

calcaneus via the calcaneal tendon

What is the action of the gastrocnemius?

plantar flexes the foot

What muscle is this? (deep)

soleus