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The Lower Limb
Consists of;
• the gluteal region (buttocks)
• the thigh
• the leg, and
• the foot
...


Locomotion
To move the body through space
...


THE PELVIS BONE
The pelvis is made up of the sacrum and the coccyx bound to each
other by dense ligaments, Ilium, Ischium, and Pubis
...
Well-defined ridges on its lateral surface are the strong
muscle markings of the glutei
...
The iliopectineal line runs
forward from the apex of the auricular surface and demarcates the true
from the false pelvis
...


The ischium has a vertically disposed body, bearing the ischial spine on
its posterior border which demarcates an upper (greater) and lower
(lesser), sciatic notch
...
The obturator foramen lies
bounded by the body and rami of the pubis and the body and ramus of
the ischium
...


THE FEMUR
The femur is the largest bone in the body
...
The femoral head is two-thirds of a
sphere and faces upwards, medially and forwards
...
The neck is 2 in (5 cm) long and is set at an angle of 125°
to the shaft
...
The junction between the neck and the shaft is marked
anteriorly by the trochanteric line, laterally by the greater
trochanter, medially and somewhat posteriorly by the lesser
trochanter and posteriorly by the prominent trochanteric crest,
which unites the two trochanters
...
Posteriorly also it is marked by
a strong crest, the linea aspera
...
The medial supracondylar line ends distally in the
adductor tubercle
...

The lateral condyle is the more prominent of the two and acts as a
buttress to assist in preventing lateral displacement of the patella

The posterior aspect of right femur

The blood supply to the femoral head is
derived from vessels travelling
up from the diaphysis along the cancellous
bone, from vessels in the hip
capsule, where this is reflected on to the
neck in longitudinal bands or
retinacula, and from the artery in the
ligamentum teres; this third source
is negligible in adults, but essential in
children, when the femoral head is
separated from the neck by the cartilage of
the epiphyseal line

Through the
diaphysis

The sources of blood supply of
the femoral head—along the
ligamentum teres, through the
diaphysis and via the retinacula
...
The upper end of the femur is a common site for fracture in the elderly
...
Fractures of the femoral neck will
interrupt completely the blood supply from the diaphysis and, should the
retinacula also be torn, avascular necrosis of the head will be inevitable
...
Avascular necrosis of the
femoral head in children is seen in Perthe’s disease and in severe slipped
femoral epiphysis; both resulting from thrombosis of the artery of the
ligamentum teres
...
There is a curious age pattern of hip injuries; children may
sustain greenstick fractures of the femoral neck, school boys may displace the
epiphysis of the femoral head, in adult life the hip dislocates and, in old age,
fracture of the neck of the femur again becomes the usual lesion
...
(b) A subcapital fracture
cuts off most of the retinacular supply to the head—aseptic bone
necrosis is common
...
The proximal segment is flexed by iliacus and psoas
and abducted by gluteus medius and minimus, whereas the distal segment is
pulled medially by the adductor muscles
...

Fractures of the lower end of the shaft, immediately above the condyles, are
relatively rare; fortunately so, because they may be extremely difficult to
treat since the small distal fragment is tilted backwards by gastrocnemius,
the only muscle which is attached to it
...


The deformities of femoral shaft fractures
...
(b) Fracture of the mid-shaft—
flexion of the proximal fragment by iliacus and psoas
...
(In all these fractures
overriding of the bone ends is produced by muscle
spasm
...
This may result from
adduction fractures, slipped of the femoral epiphysis or bone-softening
diseases
...
Note, however, that in children
the normal angle between the neck and shaft is about 160°
...
The posterior surface of the
patella is covered with cartilage and articulates with the two femoral
condyles by means of a larger lateral and smaller medial facet
...
These
resist the tendency for lateral
displacement of the patella which
results from the valgus angulation
between the femur and the tibia

CLINICAL FEATURES
Lateral dislocation of the patella is resisted by the prominent
articular surface of the lateral femoral condyle and by the medial pull
of the lowermost fibers of vastus medialis which insert almost
horizontally along the medial margin of the patella
...


 A direct blow on the patella may split or shatter it but the fragments are
not avulsed because the quadriceps expansion remains intact
...
In this case, the
tear extends outwards into the quadriceps expansion, allowing the upper
bone fragment to be pulled proximally; there may be a gap of over 2 in (5
cm) between the bone ends
...

Occasionally this same mechanism of sudden forcible quadriceps
contraction tears the quadriceps expansion above the patella, ruptures the
ligamentum patellae or avulses the tibial tubercle
...


TIBIA
The upper end of the tibia is expanded into the medial and lateral condyles, the former having the
greater surface area of the two
...
The tuberosity of the tibia is at the upper end of the anterior border
of the shaft and gives attachment to the ligamentum patellae
...
The shaft of the
tibia is triangular in cross-section, its anterior border and anteromedial surface being subcutaneous
throughout their whole extent
...
The lower end of the tibia is expanded
and quadrilateral in section, bearing an additional surface, the fibular notch, for the lower
tibiofibular joint The medial malleolus projects from the medial extremity of the bone and is
grooved posteriorly by the tendon of tibialis posterior
...


The tibia and fibula
...
Fortunately, the capsule of the knee joint is
attached closely around the articular surfaces so that the upper
extremity of the tibial diaphysis is extracapsular; involvement of the
knee joint therefore only occurs in the late and neglected case
...
It is not surprising that the tibia is the commonest long
bone to be fractured and to suffer compound injury
...


THE FIBULA
The fibula serves three functions
...

It comprises the head with a styloid process(into which is inserted the
tendon of biceps), the neck(around which passes the common peroneal
nerve; the shaft and the lower end or lateral malleolus
...
A groove on the posterior aspect of the
malleolus lodges the tendons of peroneus longus and brevis
...
The site of the growing end is of considerable practical
significance; for example, if a child has to undergo and above-elbow
amputation, the humeral upper epiphyseal line continues to grow and
the elongating bone may well push its way through the stump end,
requiring reamputation
...
It is a perfect example of a ball-and-socket
joint
...
The non-articular lower part of the acetabulum, the acetabular
notch, is closed off below by the transverse acetabular ligament
...
The
capsule of the hip is attached proximally to the margins of the acetabulum and to
the transverse acetabular ligament
...
5 in (12 mm) from the trochanteric crest
...
Note that acute osteomyelitis of
the upper femoral metaphysis will involve the neck which is intracapsular and
which will therefore rapidly produce a secondary pyogenic arthritis of the hip joint
...
the iliofemoral (Y-shaped ligament of Bigelow)—which arises from the
anterior inferior iliac spine, bifurcates, and is inserted at each end of the
trochanteric line
...
the pubofemoral—arising from the iliopubic junction to blend with the
medial aspect of the capsule;
3
...

Of these, the iliofemoral is by far the strongest and resists hyperextension
strains on the hip
...
The
synovium of the hip covers the non-articular surfaces of the joint and
occasionally bulges out anteriorly to form a bursa beneath the psoas tendon
where this crosses the front of the joint
...
The principal muscles
acting on the joint are:
 flexors—iliacus and psoas major assisted by rectus femoris, sartorius, pectineus;
extensors—gluteus maximus, the hamstrings;
 adductors—adductor longus, brevis and magnus assisted by gracilis and
pectineus;
 abductors—gluteus medius and minimus, tensor fasciae latae;
lateral rotators—principally gluteus maximus assisted by the obturators, gemelli
and quadratus femoris;
medial rotators—tensor fasciae latae and anterior fibres of gluteus medius and
minimus
...


Surgical exposure of the hip joint therefore inevitably involves considerable and
deep dissection
...

Further access may be obtained by detaching the greater trochanter with the
gluteal insertions
...
More room may be obtained
by detaching these glutei from the external aspect of the ilium
...
Gluteus maximus is split in the line of its fibres and then incised
along its tendinous insertion
...
) and an excellent view of the hip joint is thus
obtained
...

It is important to note that these nerves also supply the knee joint and,
for this reason, it is not uncommon for a patient, particularly a child, to
complain bitterly of pain in the knee
...
When standing on one leg, the
abductors of the hip on this side (gluteus medius and minimus and tensor fasciae
latae) come into powerful action to maintain fixation at the hip joint, so much so
that the pelvis actually rises slightly on the opposite side
...

This positive Trendelenburg test is seen if the hip abductors are paralysed (e
...

poliomyelitis), if there is an old unreduced or congenital dislocation of the hip, if
the head of the femur has been destroyed by disease or removed operatively
(pseudarthrosis), if there is an un-united fracture of the femoral neck
...
A
patient with any of the conditions enumerated above walks with a characteristic
‘dipping gait’
...
g
...
If the hip is also in the adducted position, the head of the
femur is unsupported posteriorly by the acetabulum and dislocation
can occur without an associated acetabular fracture
...
The sciatic nerve, a close posterior relation of
the hip, is in danger of damage in these injuries
...
If the hip is forced into posterior
dislocation while adducted (a), there is no associated fracture
of the posterior acetabular lip (b)
...

Occasionally, forcible abduction of the hip will dislocate the hip
forwards
...
g
...


THE KNEE JOINT
The knee is a hinge joint made up of the articulations between the
femoral and tibial condyles and between the patella and the patellar
surface of the femur
...
(b) The right
knee in transverse section

The capsule is attached to the margins of these articular surfaces but
communicates above with the suprapatellar bursa (between the lower
femoral shaft and the quadriceps), posteriorly with the bursa under the
medial head of gastrocnemius and often, through it, with the bursa under
semimembranosus
...
The capsule is also perforated posteriorly by
popliteus, which emerges from it in much the same way that the long head
of biceps bursts out of the shoulder joint
...

Anteriorly, the capsule is considerably strengthened by the ligamentum
patellae, and, on each side of the patella, by the medial and lateral patellar
retinacula, which are expansions from vastus medialis and lateralis
...


MOVEMENT OF THE KNEE JOINT
The principal knee movements are flexion and extension, but note on yourself that
some degree of rotation of the knee is possible when this joint is in the flexed
position
...
e
...
The first step in flexion of the fully extended knee is ‘unscrewing’ or
internal rotation
...

The principal muscles acting on the knee are:
I
...
flexors—hamstrings assisted by gracilis, gastrocnemius and sartorius;
III
...


CLINICAL FEATURES
1
...
Of the two, the muscles are
by far the more important
...
Conversely, the most skilful surgical
repair of torn ligaments is doomed to failure unless the muscles are
functioning strongly; without their support, reconstructed ligaments
will merely stretch once more
...
When considering soft tissue injuries of the knee joint, think of three
Cs that may be damaged—the Collateral ligaments, the Cruciates and
the Cartilages
...
The medial
ligament may be partly or completely torn when a violent abduction
strain is applied, whereas an adduction force may damage the lateral
ligament
...
The anterior
cruciate, which is taut in extension, may be torn by violent
hyperextension of the knee or in anterior dislocation of the tibia on the
femur
...
The posterior cruciate tears in a posterior
dislocation
...
If there is
only increased forward mobility, the anterior cruciate ligament has
been divided or is lax
...
The semilunar cartilages can only tear when the
knee is flexed and is thus able to rotate
...
The superior tibiofibular joint, a synovial joint between the head of
the fibula and the lateral condyle of the tibia;
II
...
The inferior tibiofibular joint, a fibrous joint, the only one in the
limbs, between the triangular areas of each bone immediately
above the ankle joint
...
The capsule of the joint fits closely
around its articular surfaces, and, as in every hinge joint, it is weak
anteriorly and posteriorly but reinforced laterally and medially by
collateral ligaments
...


MOVEMENT OF THE ANKLE
The ankle joint is capable of being flexed and extended (plantar- and
dorsiflexion)
...

Conversely, in flexion, there is slight laxity at the joint and some degree
of side to side tilting is possible
...


1
...
If the ligament is completely disrupted the talus can be
tilted in its mortice; this is difficult to demonstrate clinically and is best
confirmed by taking an anteroposterior radiograph of the ankle while forcibly
inverting the foot
...
The most usual ankle fracture is that produced by an abduction-external
rotation injury; the patient catches his foot in a rabbit hole, his body and his
tibia internally rotate while the foot is rigidly held
...
These stages are termed 1st, 2nd and 3rd
degree Pott’s fractures
...


Inversion and eversion of the foot take place at the talocalcaneal
articulations and at the mid-tarsal joints between the calcaneum and
the cuboid and between the talus and the navicular
...
Hold your calcaneus between
your finger and thumb; inversion and eversion are prevented
...
g
...
Inversion is brought
about by tibialis anterior and posterior assisted by the long extensor
and flexor tendons of the hallux; eversion is the duty of peroneus
longus and brevis, (peroneus tertius forms part of the extensor
muscles)
...


THE ARCHES OF THE FOOT
The bones of the foot are arranged in the form of two longitudinal
arches
...
The lateral arch, which is lower, comprises the calcaneus, cuboid
and the lateral two metatarsals
...


The longitudinal arches of the right foot
...
(b) Lateral view
...
The shape of the interlocking bones;
2
...
muscle action
...
The dorsal, plantar and interosseous ligaments between the small bones of the forefoot
2
...
The long plantar ligament which arises from the posterior tuberosity on the plantar surface of
the calcaneus, covers the short plantar ligament, forms a tunnel for peroneus longus tendon
with the cuboid, and is inserted into the bases of the 2nd, 3rd and 4th metatarsals
...


Plantar aspect of the left foot to show
the attachments of the important
ligaments and long tendons
...


Three important zones of the
lower limb
1
...

Its floor consists of iliacus, the tendon of psoas, pectineus and adductor longus
...

The contents of the triangle are the femoral vein, artery and nerve together with
the deep inguinal nodes
...
Above, it is
attached all around to the root of the lower limb—that is to say, to the
inguinal ligament, pubis, ischium, sacrotuberous ligament, sacrum and
coccyx and the iliac crest
...
The
iliotibial tract, when tensed by its attached muscles, assists in the
stabilization of the hip and the extended knee when standing
...


The femoral sheath and femoral canal
The femoral artery and vein enter the femoral triangle from beneath
the inguinal ligament within a fascial tube termed the femoral sheath
...
The medial part of the femoral
sheath contains a small, almost vertically placed gap, the femoral canal,
which is about 0
...
The greater width of the female pelvis means the canal
is somewhat larger in the female and femoral hernia are, consequently,
commoner in this sex
...
The canal contains a plug of fat and a constant lymph node—the
node of the femoral canal or Cloquet’s gland
...


NB, The femoral nerve lies outside
the femoral sheath

The femoral canal and its surrounds
...
Unlike the indirect inguinal hernia, this is
never due to a congenital sac and, although cases do occur rarely in
children, it is never found in the newborn
...


The adductor canal (of Hunter) or
subsartorial canal

This canal leads on from the apex of the femoral triangle
...

The contents of the canal are the femoral artery, the femoral vein (which lies
behind the artery), the saphenous nerve and, in its upper part, the nerve to
vastus medialis from the femoral nerve
...


The popliteal fossa
The popliteal fossa is the distal continuation of the adductor canal
...

Its boundaries are:
superolaterally—biceps tendon;
superomedially—semimembranosus reinforced by semitendinosus;
inferomedially and inferolaterally—the medial and lateral heads of gastrocnemius
...
From without in, the popliteal fossa contains nerves,
vein and artery

The popliteal fossa
...
(b) Deep
...


Clinical features
The popliteal fossa is another good example of the value of thinking anatomically
when considering the differential diagnosis of a mass situated in a particular
anatomical area
...


The arteries of the lower limb
Femoral artery
The femoral artery is the distal continuation of the external iliac artery
beyond the inguinal ligament
...
Throughout its course, the femoral artery
is accompanied by its vein, which lies first on the medial side of the
artery and then passes posteriorly to it at the apex of the femoral
triangle
...

These three vessels are encountered in the groin incision for repair for an inguinal
hernia
...
The
profunda femoris arises posterolaterally from the femoral artery 2 in (5 cm) distal
to the inguinal ligament
...
The
profunda passes deep to adductor longus and gives off medial and lateral
circumflex branches and four perforating branches
...


CLINICAL ANATOMY
1
...
A
laceration of the femoral artery at this site is an occupational hazard of
butchers and bullfighters
...
The femoral artery at the groin is readily punctured by a hypodermic needle
and is the most convenient site from which to obtain arterial blood samples
...
Arteriosclerotic changes, with consequent thrombotic arterial occlusion,
frequently commence at the lower end of the femoral artery, perhaps as a
result of compression of the diseased vessel by the margins of the hiatus in
adductor magnus
...
If
arteriography demonstrates a patent arterial tree distal to the block, it is
possible to bypass the occluded segment by means of a graft between the
common femoral and popliteal arteries
...
It lies deep within the popliteal fossa, being covered
superficially by the popliteal vein and, more superficially still, crossed
by the tibial nerve
...


Clinical features
1
...
Its
frequency in former days was associated with the repeated
traumata of horse-riding and the wearing of high riding-boots
...

2
...
It can also be exposed by a medial
approach, which divides the insertion of adductor magnus and
detaches the origin of the medial head of gastrocnemius from the
tibia
...
It descends deep to soleus, where it can be exposed by splitting
gastrocnemius and soleus in the midline, then becomes superficial in the lower
third of the leg and passes behind the medial malleolus between the tendons of
flexor digitorum longus and flexor hallucis longus
...
Below the ankle, the posterior tibial
artery divides into the medial and lateral plantar arteries which constitute the
principal blood supply to the foot
...
5 in (4 cm) from it origin
...
Above the ankle it gives
off its perforating branch which pierces the interosseous membrane, descends over
the lateral malleolus and anastomoses with the arteries of dorsum of the foot
...
It
passes forwards between the tibia and fibula under the lower border of
popliteus over the upper margin of the interosseous membrane and
descends on this structure in the anterior compartment of the leg
...
The artery continues over the dorsum of the foot as the dorsalis pedis
(where its pulse may be palpated); this gives off the arcuate which, in turn,
supplies cutaneous branches to the backs of the toes
...


The relations of the posterior tibial artery as it passes behind the
medial malleolus

The veins of the lower limb
The veins of the lower limb are divided into the deep and superficial groups
according to their relationship to the investing deep fascia of the leg
...
The superficial
veins are the great and small(or long and short) saphenous veins and their
tributaries
...
It courses over the back of the calf, perforates the deep
fascia over the popliteal fossa and terminates in the popliteal vein
...
The small saphenous vein is accompanied by the sural nerve—a
sensory branch of the tibial nerve, which may be damaged in operating on
varices of this vein
...
The vein then ascends over the posterior parts of the medial condyles of the
tibia and femur to the groin where it pierces the deep fascia at the saphenous
opening 1in(2
...
The great saphenous vein is joined by
one or more branches from the small saphenous, and by the lateral accessory vein
which usually enters the main vein at the mid-thigh, although it may not do so until
the saphenous opening is reached
...
the superficial epigastric vein;
2
...
the superficial external pudendal vein
...


2
...


4
...
Its presence at this site, even if not visible in an
obese or collapsed patient, may be life-saving when urgent transfusion is required
...

The saphenous veins frequently become dilated, incompetent and varicose
...

Stagnation of blood in the skin of the lower limb may result from venous thrombosis or valve
incompetence; the skin, in consequence, is poorly nourished and easily breaks down into a
varicose ulcerif subjected to even minor trauma
...

In operating upon varicose veins it is important that all tributaries of the groin are ligated as
well as the main saphenous trunk; if one tributary escapes, it in turn becomes dilated and
produces recurrence of the varices
...
The trunks of the plexus traverse psoas
major and emerge from its lateral border
...
The
principal branches of the plexus are the femoral nerve and the obturator nerve
...
Its
branches are:
1
...
cutaneous—the medial and intermediate cutaneous nerves of the thigh and the saphenous nerve, which
traverses the adductor canal to supply the skin of the medial side of the leg, ankle and foot to the great
toe;
3
...

The femoral nerve supplies the skin of the medial and anterior aspects of the thigh via its medial and
intermediate cutaneous branches, but the lateral aspect is supplied by the lateral cutaneous nerve of the thigh
(L2–3)
...


The obturator nerve(L2–4) emerges from the medial aspect of the
psoas and runs downwards and forwards, deep to the internal iliac
vessels, to reach the superior part of the obturator foramen
...
Its
branches are:
1
...
cutaneous—to an area of skin over the medial aspect of the thigh;
3
...


Plan of the lumbar plexus (muscular branches have been omitted
for clarity)

Clinical features
1
...
Rarely, an obturator hernia develops through the canal where the
obturator nerve and vessels traverse the membrane covering the
obturator foramen
...

3
...


The sacral plexus
This plexus originates from the anterior primary rami of L4–5, S1– 4
...
The
sacral nerves emerge from the anterior sacral foramina and unite in front of
piriformis where they are joined by the lumbosacral trunk
...
the pelvic muscles;
2
...
the skin of the buttock and the back of the thigh
...
The
pudendal nerve supply the skin of the external genitalia
...


Pudendal nerve contd
It arises as the lower main division of the sacral plexus although it is
dwarfed by the giant sciatic nerve
...
Within the canal it first
gives off the inferior rectal nerve, which crosses the fossa to innervate
the external anal sphincter and the perianal skin, and then divides into
the perineal nerve and the dorsal nerve of the penis (or clitoris)
...


Clinical features
The pudendal nerve can be blocked with local anaesthetic prior to
forceps delivery by inserting a long needle through the vaginal wall and
guided by a finger to the ischial spine, which can be palpated per
vaginam
...
5 cm)
...


The sciatic nerve
The sciatic nerve (L4, 5, S1–3) is the largest nerve in the body
...

The nerve emerges from the greater sciatic foramen distal to piriformis
and under cover of gluteus maximus, crosses the posterior surface of
the ischium, crosses obturator internus, with its gemelli, quadratus
femoris and descends on adductor magnus
...
The sciatic
nerve terminates by dividing into the tibial and common peroneal
nerves
...


Branches
The trunk of the sciatic nerve supplies the hamstring muscles (biceps,
semimembranosus, semitendinosus) and also the adductor magnus,
the latter being innervated also by the obturator nerve
...
The tibial nerve(L4, 5, S1–3) is
the larger of the two terminal branches of the sciatic nerve; it traverses
the popliteal fossa superficial to the popliteal vein and artery, which it
crosses from the lateral to the medial side
...

It then descends deep to soleus, in company with the posterior tibial vessels, passes on
their lateral side behind the medial malleolus to end by dividing into the media land lateral
plantar nerves
...
Its terminal plantar branches supply the intrinsic muscles and skin of the sole of
the foot, the medial plantar nerve having an equivalent distribution to that of the median
nerve in the hand, the lateral plantar nerve being comparable to the ulnar nerve
...
It enters the upper part of the popliteal
fossa, passes along the medial border of the biceps tendon, then
curves around the neck of the fibula where it lies in the substance of
peroneus longus and divides into its terminal branches, the deep
peroneal and superficial peroneal nerves

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