Table 1 Origin, insertion and function of major locomotor muscles of the varanid hindlimb based on Snyder, [21], Gans et al., [22], Reilly, [23] and Anzai et al., [24]

Adductor femoralis

AFEM

femur adduction, femur protraction

Both^a

puboischiadic ligament

ventral aspect of femoral shaft

Ambiens (dorsal head)

AMB (D)

knee extension

Stance

ventral rim of acetabulum

intertrochanteric notch of femur

Ambiens (ventral head)

AMB (V)

knee extension

Stance

pubis (anterior to the acetabulum)

intertrochanteric notch of femur

Caudofemoralis brevis

CFEMB

femur retraction, femur long axis rotation

Stance

posterior aspects of transverse processes of four most anterior postsacral vertebrae

fleshily, onto posterior ventral border of femoral trochanter

Caudofemoralis longus

CFEML

femur retraction, femur long axis rotation, knee flexion

Stance

proximal third of tail and 4th to 14th caudal vertebrae

broad tendon inserts onto femoral trochanter and 2nd tendon onto lateral menisci of knee

Extensor digitorum longus

EDL

ankle dorsiflexion

Swing

dorsal medial aspect of femoral epicondyle

dorsal lateral surface of 2nd and 3rd metatarsals

Femorotibialis

FTIB

knee extension

Both^a

fleshily from entire length of femoral shaft

joins with tendon of iliotibialis to insert on cnemial crest of tibia

Flexor digitorum longus

FDL

ankle plantarflexion

Stance

femoral lateral epicondyle

Complex. Distally gives rise to a stout tendon which attaches to digits one to four

Flexor tibialis externus

FTE

knee flexion

Stance

ilioischiadic ligament

proximal lateral surface of tibia

Flexor tibialis internus (deep head)

FTI (D)

femur adduction, knee flexion

Stance^a

posterior ventral margin of the ischium

tendon arises halfway down belly of FTI to insert onto proximal lateral surface of tibia

Flexor tibialis internus (superficial head)

FTI (S)

femur adduction, knee flexion

Both^a

perineal region and anterior aspect of ilioischiadic ligament

inserts via 2 tendons onto proximal end of medial shaft of tibia and proximal lateral surface of tibia

Gastrocnemius

GAST

ankle plantarflexion

Stance^a

Ventral surface of the proximal end of the tibia, and the distal end of the ventral crest of the tibia

broad aponeurosis which inserts on the proximolateral margins of the first three phalanges

Iliofemoralis

ILFEM

femur abduction

Swing

anterior aspect of blade of ilium (shares an intramuscular septum with puboischiotibialis)

belly wraps around posterior border of femur to insert into proximal aspect of posterior border of femur

Iliofibularis

ILFIB

knee flexion

Swing

fleshily from posterior ventral margin of ilium

broad flat tendon attaches onto proximal shaft of fibula (passes between peroneus longus and gastrocnemius)

Iliotibialis

ILTIB

knee extension

Stance

2 tendons with broad aponeurosis on lateral surface of ilium

inserts with femorotibialis onto cnemial crest of tibia (note the patella is imbedded in this tendon)

Peroneus brevis

PBREV

ankle dorsiflexion

Swing

broad origin on most dorsal aspects (medial and lateral) of fibula

broad tendon inserts onto the outer process of 5th metatarsal head

Peroneus longus

PLONG

ankle plantarflexion

Both^a

short tendon from lateral femoral epicondyle

proximal end of the lateral plantar tubercle of 5th metatarsal

Puboischiofemoralis

PIF

femur protraction

Swing

anterior rim of pubic plate, pubic symphysis, ischiadic symphysis and posterior end of thyroid fenestra

femoral trochanter and posterior dorsal margin of femur

Puboischiotibialis

PIT

knee flexion

Both^a

anterior aponeurosis and from ischiopubic ligament posteriorly

anterior medial aspect of proximal end of tibia

Pubotibialis

PTIB

femur adduction, knee flexion

Both^a

pubic tubercle

proximal lateral aspect of tibia

Tibialis anterior

TIBA

ankle dorsiflexion

Both^a

anterior medial aspect of tibial head and anterior dorsal surfaces of tibial shaft

ventral medial aspect of proximal end of 1st metatarsal and base of first metatarsal and metatarsophalangeal joint distally