Alphabetical listing of muscles
Gemellus inferior
Action: laterally rotates hip
Origin : upper part of ischial tuberosity
Insertion: with obturator internus tendon into medial surface
of greater trochanter
Nerve: nerve to quadratus femoris (L5, S1)
Gemellus superior
Action: laterally rotates hip
Origin : gluteal surface of ischial spine
Insertion: with obturator internus tendon into medial surface
of greater trochanter
Nerve: nerve to obturator internus (L5, S1)
Gluteus maximus
Action : extends, laterally rotates and abducts hip
Origin: posterior gluteal line of ilium, posterior border of
ilium and adjacent part of iliac crest, aponeurosis of erector spinae,
posterior aspect of sacrum, side of coccyx, sacrotuberous ligament,
gluteal aponeurosis
Insertion: iliotibial tract of fascia lata, gluteal tuberosity of femur
Nerve : inferior gluteal nerve (L5–S2)
Gluteus medius
Action : abducts and medially rotates hip
Origin: gluteal surface of ilium between posterior and ante-
rior gluteal lines
Insertion : superolateral side of greater trochanter
Nerve : superior gluteal nerve (L4–S1)
,Gluteus minimus
Action : abducts and medially rotates hip
Origin: gluteal surface of ilium between anterior and inferior
gluteal lines
Insertion : anterolateral ridge on greater trochanter
Nerve : superior gluteal nerve (L4–S1)
Gracilis
Action: flexes knee, adducts hip, medially rotates tibia on
femur
Origin: lower half of body and inferior ramus of pubis, adja-
cent ischial ramus
Insertion : upper part of medial surface of tibia
Nerve : obturator nerve (L2, L3)
Iliacus
Action : flexes hip and trunk
Origin: superior two-thirds of iliac fossa, inner lip of iliac
crest, ala of sacrum, anterior sacroiliac and iliolumbar ligaments
Insertion: blends with insertion of psoas major into lesser trochanter
Nerve: femoral nerve (L2, L3)
Iliocostalis cervicis
Action: extends and laterally flexes vertebral column
Origin : angles of third to sixth ribs
Insertion: posterior tubercles of transverse processes of C4 to C6
Nerve: dorsal rami
Iliocostalis lumborum
Action: extends and laterally flexes vertebral column
Origin : medial and lateral sacral crests, spines of T11, T12
and lumbar vertebrae and their supraspinous ligaments, medial part of
iliac crest
, Insertion : angles of lower six or seven ribs
Nerve: dorsal rami
Iliocostalis thoracis
Action: extends and laterally flexes vertebral column
Origin : angles of lower six ribs
Insertion : angles of upper six ribs, transverse process of C7
Nerve: dorsal rami
Inferior oblique
Action: rotates atlas and head
Origin : lamina of axis
Insertion : transverse process of atlas
Nerve: dorsal ramus (C1)
Infraspinatus
Action: laterally rotates shoulder
Origin: medial two-thirds of infraspinous fossa and infraspinous fascia
Insertion : middle facet on greater tubercle of humerus, posterior aspect
of capsule of shoulder joint
Nerve: suprascapular nerve (C5, C6)
Intercostales externi
Action: elevate rib below towards rib above to increase thoracic cavity
volume for inspiration
Origin: lower border of rib above
Insertion : upper border of rib below
Nerve : intercostal nerves
Intercostales interni
Action: draw ribs downwards to decrease thoracic cavity volume for
expiration
Origin: lower border of costal cartilage and costal groove of
rib above
Gemellus inferior
Action: laterally rotates hip
Origin : upper part of ischial tuberosity
Insertion: with obturator internus tendon into medial surface
of greater trochanter
Nerve: nerve to quadratus femoris (L5, S1)
Gemellus superior
Action: laterally rotates hip
Origin : gluteal surface of ischial spine
Insertion: with obturator internus tendon into medial surface
of greater trochanter
Nerve: nerve to obturator internus (L5, S1)
Gluteus maximus
Action : extends, laterally rotates and abducts hip
Origin: posterior gluteal line of ilium, posterior border of
ilium and adjacent part of iliac crest, aponeurosis of erector spinae,
posterior aspect of sacrum, side of coccyx, sacrotuberous ligament,
gluteal aponeurosis
Insertion: iliotibial tract of fascia lata, gluteal tuberosity of femur
Nerve : inferior gluteal nerve (L5–S2)
Gluteus medius
Action : abducts and medially rotates hip
Origin: gluteal surface of ilium between posterior and ante-
rior gluteal lines
Insertion : superolateral side of greater trochanter
Nerve : superior gluteal nerve (L4–S1)
,Gluteus minimus
Action : abducts and medially rotates hip
Origin: gluteal surface of ilium between anterior and inferior
gluteal lines
Insertion : anterolateral ridge on greater trochanter
Nerve : superior gluteal nerve (L4–S1)
Gracilis
Action: flexes knee, adducts hip, medially rotates tibia on
femur
Origin: lower half of body and inferior ramus of pubis, adja-
cent ischial ramus
Insertion : upper part of medial surface of tibia
Nerve : obturator nerve (L2, L3)
Iliacus
Action : flexes hip and trunk
Origin: superior two-thirds of iliac fossa, inner lip of iliac
crest, ala of sacrum, anterior sacroiliac and iliolumbar ligaments
Insertion: blends with insertion of psoas major into lesser trochanter
Nerve: femoral nerve (L2, L3)
Iliocostalis cervicis
Action: extends and laterally flexes vertebral column
Origin : angles of third to sixth ribs
Insertion: posterior tubercles of transverse processes of C4 to C6
Nerve: dorsal rami
Iliocostalis lumborum
Action: extends and laterally flexes vertebral column
Origin : medial and lateral sacral crests, spines of T11, T12
and lumbar vertebrae and their supraspinous ligaments, medial part of
iliac crest
, Insertion : angles of lower six or seven ribs
Nerve: dorsal rami
Iliocostalis thoracis
Action: extends and laterally flexes vertebral column
Origin : angles of lower six ribs
Insertion : angles of upper six ribs, transverse process of C7
Nerve: dorsal rami
Inferior oblique
Action: rotates atlas and head
Origin : lamina of axis
Insertion : transverse process of atlas
Nerve: dorsal ramus (C1)
Infraspinatus
Action: laterally rotates shoulder
Origin: medial two-thirds of infraspinous fossa and infraspinous fascia
Insertion : middle facet on greater tubercle of humerus, posterior aspect
of capsule of shoulder joint
Nerve: suprascapular nerve (C5, C6)
Intercostales externi
Action: elevate rib below towards rib above to increase thoracic cavity
volume for inspiration
Origin: lower border of rib above
Insertion : upper border of rib below
Nerve : intercostal nerves
Intercostales interni
Action: draw ribs downwards to decrease thoracic cavity volume for
expiration
Origin: lower border of costal cartilage and costal groove of
rib above
