This document describes the arterial blood supply and potential flaps in the lower limb. It discusses various fasciocutaneous and musculocutaneous flaps that can be raised based on named arteries in the lower limb, including the femoral, lateral circumflex femoral, profunda femoris, popliteal, and posterior tibial arteries. Specific flaps are described such as the anteromedial thigh flap, gracilis flap, and gastrocnemius flap. The angiosome concept and variations in vascular anatomy are also covered.

2. Lower Limb Flaps

4. Arteries in the lower leg
► Common Femoral Artery ► Dorsalis Pedis Artery and Arcuate
 Medial circumflex femoral artery Artery
 Lateral circumflex femoral artery  Deep plantar branch of DP
(+ ascending and descending  Dorsal metatarsal and digital
branches0 arteries
► Profunda Femoris  Medial and lateral tarsal arteries
 Perforating brs of PF ► Peroneal Artery
 Descending genicular artery  Perforating branch of peroneal
► Popliteal Artery artery
 Ascending branch  Lateral malleolar artery
 Genicular arteries (4) ► Posterior Tibial Artery
► Anterior Tibial Artery  Medial plantar artery
 Anterior tibial recurrent artery  Lateral plantar artery
 Medial malleolar arteries  Plantar arch, plantar metatarsal
and digital arteries

5. Femoral artery

6. Anteromedial thigh flap
► Femoral artery lies in subsartorial canal for its lower 2/3, and in this
portion gives off muscular and fasciocutaneous branches
 Perforators pass around both borders of sartorius to form a plexus at the level
of the deep fascia with an axis along the border of sartorius
 Range in size from 0.5-1mm Ø
 80% cases the largest perforator passes around the superomedial border of
sartorius in the apex of the femoral triangle
► Additionally also supplies muscle, so it’s diameter is 0.5-1.2mm
► Accompanied by a vein
► Supplies an area of 7x12cm on anteromedial thigh, with upper part of ellipse
overlying the apex of the femoral triangle
► Area is supplied by the medial anterior cutaneous nerve of the thigh
 Crosses medially in front of artery at the apex of the femoral triangle
 Can be raised as an innervated flap
► Type B fasciocutaneous flap
 Raised by identifying perforator first, the adjusting the flap position to be
centred over the artery

8. Saphenous flap
► Saphenous artery is one of three terminal branches of descending genicular branch of femoral
artery
 Given off from medial side of femoral artery immediately before if enters the adductor hiatus
 Runs under sartorius and sends cutaneous branches anterior and posterior to muscle
 Runs under insertion of tendon to emerge posteriorly and continue in lower leg, usually only for about
12cm
► 1.5-2mmØ, paired vc’s + GSV
► Safe dimensions are 6x20cm, allowing primary closure of defect
► Raised proximal to distal to visualise vessels and their relationship to tendon first
► Can raise distally based flap, useful in stump wound breakdown

10. Lateral circumflex femoral artery

11. Tensor Fascia Latae
►Origin – ASIS + iliac crest
►Insertion – Lateral condyle of tibia via fascia lata
►Innervation – Superior gluteal nerve (L4,5)
►Action – Abducts, medially rotates and flexes thigh.
Hip stabiliser and assists in keeping knee extended
►Type I muscle
 Branch off ascending branch of lateral circumflex femoral
artery
 Single artery 2-3mm diameter, paired venae comitantes
 Enters muscle on deep surface 9cm below ASIS

13. Rectus femoris
► Type II bipennate muscle supplied primarily by LCFA
► Origin: AIIS and deep/reflected part from superior acetabular rim
► Insertion: Tibial tuberosity via superior part of patella, separated from femur by
suprapatellar bursa. Deepest layer of quadriceps tendon
► Innervation: Br of Femoral nerve (L3,4), deep group, usually double
 Upper branch gives a proprioceptive branch to hip (Hiltons law)
► Action: Extend knee, stabilise hip joint and assists iliopsoas flex hip
► Reliable vascular pedicle and considerable length (7x40cm)
 Pedicle generally arises 5cm below top of symphysis pubis and runs downwards for 5-8cm before
piercing the muscle on posteromedial border at junction of proximal and middle thirds
 Divides into superior and inferior branches
► Rotation point is 7cm below inguinal ligament
► Muscle is necessary for fully functional knee extension, so is not expendable except in spinal
patients (when gracilis or TFL can be used)
► Skin paddle is based over lower 2/3 of muscle
► Skin paddle sensation is supplied by intermediate anterior cutaneous nerve of thigh

15. Vastus lateralis
► Type II muscle with dominant proximal pedicle from LCFA augmented by multiple
perforators from the posterior compartment
► Origin: Greater trochanter, lateral lip of linea aspera of femur
► Insertion: Tibial tuberosity via patella. Middle layer of quadriceps tendon
► Innervation: Br of femoral nerve (L2,3,4), deep group
► Action: Extends knee
► Descending br LCFA runs down behind anterior edge of VL with nerve supply and
terminates in muscle in 90%, skin in 10%
► As branches enter the muscle, multiple neurovascular hila are formed. One into
proximal third, three in proximal and middle third
 60% cases, branches pierce deep fascia over anterior part of muscle and supply skin
 40% cases septocutaneous perforators given off in intermuscular septum to reach deep
fascia (see ALT flap)
► Main use is in repair of trochanteric pressure sores and salvage of hip wound
 Can be raised as a free flap
► Raised as from an incision slightly lateral to a line from ASIS to superolateral
aspect of patella

17. Anterolateral thigh flap
► Type B fasciocutaneous flap
► Supplied by descending branch of lateral circumflex femoral artery, usually
associated with 2 vc’s
 Length 8 – 16cm, diameter 2-3mm
► Pedicle transverses obliquely in groove between rectus femoris and vastus
lateralis along with nerve to vastus lateralis
► Cutaneous perforators usually found in inferolateral quadrant of 3cm circle
with centre at midpoint ASIS to superolateral corner of patella
 Can be septocutaneous or musculocutaneous perforators
 Can be raised as super thin, fasciocutaneous or musculocutaneous flap
► Maximum dimensions 12x8cm, with most distal part of flap at least 4cm
above proximal end of patella
► Can incorporate anterior branch of lateral cutaneous nerve of thigh to create
sensory flap

19. Profunda femoris artery

20. Gracilis
► Origin – inferior pubic ramus, just below fascia lata
► Insertion – subcutaneous surface of tibia, just behind sartorius
► Innervation – obturator nerve
 Single nerve with multiple fascicles to different portions of muscle (so useful
in facial reanimation)
► Action – adduct thigh, flexes leg, assists medial rotation
► Type II muscle
 Adductor branch of profunda femoris or descending branch of MCFA
 Main pedicle 1-2mm diameter, paired vc’s
 One or to minor pedicles from superficial femoral artery enter muscle distally
 Pedicle courses from medial to lateral, and enters the deep surface about
10cm inferior to pubic tubercle (junction of upper 1/3 and lower 2/3) – pivot
point
► Usually used as muscle only flap, but can be used as musculocutaneous
flap with skin island over superior half of muscle

22. Hamstring flaps
► Hamstring musculocutaneous flaps
were developed for treatment of
ischial pressure sores, but can be
transposed to anterior thigh
► VY musculocutaneous unit
advancements have the advantage of
being able to be re-elevated and
advanced should pressure sores recur
► Can be raised on all 4 hamstring
components or only biceps or
semitendinosis
► Can be constructed to maintain
innervation via posterior cutaneous
nerve of thigh
► Large skin islands up to 12x35cm
extending past the muscle borders can
be raised

23. ► Biceps femoris ► Semitendinosis
 Origin: Long head from ischial  Origin: Ischial tuberosity
tuberosity, short head from linea  Insertion: Medial surface of
aspera of lateral supracondylar line superior part of tibia, just below
of femur gracilis
 Insertion: Lateral side of head of  Innervation: Tibial part of sciatic
fibula. Tendon is split by fibular nerve (L5-S2)
collateral ligament of knee  Action: Extend thigh, flex leg and
 Innervation: Long head is tibial rotate medially, extend trunk
division of sciatic nerve (L5-S2), when thigh and leg are flexed
short head is common peroneal  Arterial supply: Type II. Primary
branch of sciatic nerve (L5-S2) dominant pedicle from first
 Action: Flex leg and rotate profunda perforator and smaller
laterally, extends thigh pedicle superior to this from
 Arterial supply: Type II. Major MCFA. Also small branches from
branches from the first profunda inferior gluteal to origin, and
perforator at upper third junction. inferior medial genicular to
Branches from second perforator insertion
to lower part of long head and to
short head. No anastomoses
between short and long head.
Further minor supply from inferior
gluteal artery, MCFA, sup lat
genicular artery

25. Lateral thigh flaps
► Lateral thigh flaps are based on the perforators from profunda femoris, each of which
terminates by dividing into two branches at the point of the insertion of the lateral
intermuscular septum into the femur (deep to origin of short head of biceps femoris)
► One of these branches pierces lateral intermuscular septum to supply vastus lateralis, the
other runs on posterior aspect of intermuscular septum towards the iliotibial tract
► Consistent large perforator from 1st profunda perforator within 3cm of lower border of
gluteus maximus (may be through the muscle), often the largest of the perforators
 Can raise skin flaps of up to 8x25cm, usually pedicled (superior lateral thigh flap) due to the
relationship to gluteus insertion
► Also branch from 3rd profunda perforator (ED 1-1.5mm) at midpoint between greater
trochanter and lateral femoral condyle (middle thigh flap)
 Usually raised as a free flap due to long pedicle length
 Raised without deep fascia, so small area but thin and can be innervated
 As most perforators run anteriorly, best to plan this flap with only 1/3 – ¼ behind lateral
intermuscular septum
► Venous drainage is by paired vc’s of the cutaneous perforators that tend to join as they
approach the femur
► Nerve supply of the area is the lateral femoral cutaneous nerve
 Emerges from beneath lateral end of inguinal ligament and divides into 2 branches that run down
the iliotibial tract

27. Popliteal artery

28. Gastrocnemius
►Origin
 Medial head – Popliteal surface of femur, superior
to medial condyle
 Lateral head – Lateral aspect of lateral condyle of
femur
►Insertion – Posterior surface of calcaneus via
tendocalcaneus (Achilles tendon)
►Innervation –Tibial nerve (S1,2)
►Action – Plantarflexes ankle, raises heel
during walking, flexes knee joint

29. ►Mathes + Nahai Type I for each head
 Each head supplied by a sural artery, which arises from
popliteal artery at or slightly above the joint line and is 2-5cm
long
►Occasionally arises from common trunk, or lateral sural arises with
inferior lateral or middle genicular artery
►Artery to medial head run directly to muscle
►Artery to lateral head passes anterior to popliteal vein and tibial
nerve, may give off branches to plantaris and soleus as well as a small
vessel accompanying surely nerve
 3mm diameter with paired vc’s, one of which can be up to
4mm diameter
 Enters each head at level of tibial condyles (pivot point), with
nerves posterior to artery in 90% cases
 Within the muscles each sural artery divides into two
branches which run longitudinally between muscle fibre
bundles and often subdivide further
►Medial head can reach to lower third femur, whereas
lateral head has a smaller arc of rotation

31. Soleus
►Origin – Inferior end of lateral supracondylar
line of femur and oblique popliteal ligament
►Insertion – Posterior surface of calcaneus via
tendocalcaneus (Achilles tendon)
►Innervation –Tibial nerve (S1,2)
►Action – Plantarflexes ankle and steadies leg
on foot

32. ►Mathes + Nahai Type II muscle
 Dominant proximal supply from popliteal artery
branches and a secondary distal supply from
branches of posterior tibial artery
 Reverse flap has been described to cover heel
defects, but it’s reliability is questionable
►Used to cover middle third tibial defects
►Bipennate muscle, so can be split into larger
medial flap and a smaller lateral hemisoleus flap

33. Popliteo-posterior thigh flap
► Inconstant vessel from proximal part of
popliteal artery, so Doppler assessment is
important
► Generally reaches deep fascia 8-10cm
above plane of knee with paired vc’s and
ascends in midline
 May anastomose with br of inferior gluteal
artery that accompanies the posterior
cutaneous nerve of the thigh
► Can raise flap as high as gluteal crease, and
defect can be primarily closed if width <
10cm
► Arc of rotation allows coverage of patella,
calf and sides of upper quarter of leg
► Elevation begins inferiorly, taking skin and
deep fascia and septum between biceps
femoris and semitendinosis

34. Lateral genicular flap
►Islanded flap based on cutaneous
termination of superior lateral
genicular artery, but may have
some supply from inferior
anastomotic (or Bourgery’s)
artery
►Emerge along fascial septum, and
then fan out above the iliotibial
tract
►Unnecessary to raise iliotibial
tract unless it is required in part
of the reconstruction

35. Lower lateral thigh flap
► Essentially a lateral genicular flap with
a broad pedicle overlying the lateral
intermuscular septum that may
incorporate the 4th PFPA
► Can raise flap up to 25cm long if at
least two vessels, but 20cm vertically
by 10cm horizontally is considered
safe
► Raised leaving thin layer of loose
areolar tissue over iliotibial tract to
allow successful skin grafting
► Exposure and mobilisation of pedicle
if required necessitates division of
vastus lateralis and short head of
biceps

36. (Lower) Posterolateral thigh flap
►Lower lateral thigh flap
raised with a broad
pedicle to include the
vertical midline branch
of the popliteal artery

37. Lower leg

38. Calf fasciocutaneous
► Commonly raised on perforators
from posterior tibial arteries
 Emerge from between soleus and
FDL
 5-6 perforators given off, tend to
be larger proximally
 Branch on reaching deep fascia
which spread anteroposteriorly
and slightly inferiorly
► Can also be raised off peroneal
artery from posterior peroneal
septum
► Important to raise flaps with
fascia. Generally only 3:1 . Can
be distally based and/or
islanded

39. Neurofasciocutaneous flaps
► Sural or saphenous nerves
► Rely on vasanervorum and vasovasorum
for supply of a distally based flap
► Skin island marked along axis of sural
nerve and small saphenous vein, with
rotation point 5-7cm above lateral
malleolus
► Can raise up to 10x13cm flap with delay
procedures
► Allows flap coverage without sacrificing
major vessels
► Flap raised with deep fascia and SSV with
subcutaneous pedicle 4cm wide. Medial
sural nerve left intact
► Can be made sensate by inclusion of lateral
sural nerve and retrograde dissection of
adequate stalk length
► Useful in heel and Achilles tendon
coverage

40. Fibular osteocutaneous flap
► Type C osteofasciocutaneous flap
► Nutrient vessel to the fibula is given off about 7cm from the origin of the
artery and penetrates the bone on the posterior or medial surface, posterior
to interosseous membrane
► Nutrient foramen lies in middle third of bone on average 17cm from styloid
process of fibula
► Cutaneous perforators pass along the posterior peroneal septum to reach
the skin
► Can run through part of FHL +/- soleus, so most surgeons take a cuff of
muscle posterior to septum in raising the flap
► Largest perforators lie between 10 and 20cm below the head of the fibula
► Skin ellipse marked so that 1/3 is anterior to septum, 2/3 behind (max
dimensions are 5cm anterior, 10cm posterior), centered on 10-20cm below
fibular head
► Posterior edge dissected first, then anterior, the bone mobilised
► Distal 5cm of fibula should be left to maintain the ankle mortise
► Can raise free fibula with epiphysis

43. Supramalleolar flap
► Distally based flap raised on anterior perforating branch of
peroneal artery
 Pierces intermuscular septum about 5cm above lateral malleolus and
divides into deep br and superficial cutaneous br
 SCB emerges between EDL and peroneus brevis and directs branches
proximally to supply an area of 8x16cm
► Planned around pivot point as described above, with lateral
border no further posterior than line of fibula
► Adequate rotation may require a back cut in the line of the 5th
toe
► Flap raised from anteromedial edge, preserving the
superficial peroneal nerve, then down to deep fascia

45. Lateral calcaneal flap
►Based on the calcaneal branches of the peroneal
artery in the foot
►Follows peroneus longus tendon about 1cm
posterior to it, 5-8mm anterior to Achilles tendon at
the ankle down to 3cm inferior to tip of fibula before
continuing to tuberosity of 5th metatarsal before
anastomosing with lateral plantar artery
►Venous drainage of the area is via the lesser
saphenous vein, and innervation by sural nerve (lies
anterior to SSV)
►Can be raised islanded or reverse flow

47. Dorsalis pedis
► Cutaneous supply of DP proper is a strip 2-3cm wide from extensor retinaculum to
half way along interosseous space
 Distal to this is supplied by 1st dorsal metatarsal artery, which lies beneath EHL tendon,
and can have a deep origin in up to 20% cases
 Lateral to this area is supplied by the lateral tarsal and arcuate arteries, which cannot be
included in the flap as they are deep to EDB and the long extensor tendons
 So usual flap plan relies on subcutaneous anastomoses between these supplies
 Distal end is prone to necrosis, so delay procedures are common
► Planned with proximal end of flap at inferior extensor retinaculum, distal end is
proximal to web spaces, lateral extent is the borders of the foot
► Paired vc’s accompany the dorsalis pedis
► Innervation of the area is by the superficial peroneal nerve, with 2PD ≈ 15mm
► Plane of elevation must leave enough paratenon for split skin graft take
► Transposition flaps utilising just the skin supplied by the 1 st dorsal metatarsal artery
are useful in managing foot scars and local tissue loss, and reverse flow dorsalis
pedis flaps can be used in managing midfoot amputation stumps

50. Lateral plantar
► Posterior tibial artery consistently divides into medial and lateral plantar
branches at about the posterior edge of the sustentaculum tali
► LPA gives off several calcaneal branches that pierce FDB and plantar
aponeurosis near the attachment to medial tubercle of calcaneus before
running distally between FDB and flexor accessorius until lateral border of
plantar aponeurosis
► The LPA supplies lateral border of 5th toe and curves medially to form the
deep plantar arch
► Sensory innervation of the sole is by lateral plantar nerve in the lateral
third and by medial plantar nerve in the medial two thirds
► This supply allows rotation/advancement flaps of the calcaneal branches
or the entire lateral part of the sole to cover heel defects (FDB
musculocutaneous flap)
 Has also been raised retrograde to cover 4 th + 5th metatarsal heads

52. Medial plantar
► MPA runs between abductor hallucis and FDB, and sends cutaneous supply to
medial sole via perforators that pass superior and (mainly) inferior to abductor
hallucis
► Medial sole is innervated by medial plantar nerve (tibial nerve usually divides
proximal to the posterior tibial artery, and the nerve usually runs medial to the
artery)
► Venous drainage of the area is via the GSV and paired vc’s that accompany the
MPA
► The flap is planned to avoid weight bearing areas and not to extend above the
tuberosity of the navicular bone
 Lateral edge of abductor hallucis is the axis along which cutaneous perforators emerge,
and so the flap axis (surface marking is centre of heel to the medial sesamoid of the
great toe, or the medial edge of the plantar aponeurosis)
 Proximal incision to the sustentaculum tali may be required for dissection of the pedicle
 Flaps can be raised up to 10cm long x 7cm wide
► Flaps can be raised proximally or distally based, and in combination with lateral
plantar artery

54. Toe flaps
►Multiple options based on plantar digital
arteries and nerves
 Complete toe transfer (or paired toe transfer)
 Pulp transfer (+/- nail bed)
 Homodigital neurovascular island flap
 Composite PIP or MCP joint