Transcript Clinical anatomy of the lower limb I (fractures)

Clinical Anatomy Lecture I
LOWER LIMB
FRACTURES AND DISLOCATIONS
Dr Vindye R Walpola
Lecturer in Anatomy
Department of Anatomy
FEMUR
Upper end consists of head, neck,
greater and lesser trochanters.
Head forms roughly 2/3 of sphere.
Shaft of femur is slightly twisted and
curved with convexity forward.
Neck extends inferolaterally from
head to meet shaft of femur at angle
of about 125 degrees
(<120 : Coxa vara, >135 : Coxa vulga)
Angle varies with age, stature and
width of pelvis.
(less in adults, in persons with short limbs,
and in women)
FEMUR
First long bone to ossify in cartilage at 7th week of
fetal life
Ossification of femur
• Centre of the shaft (7th week IU)
• Lower end of femur (9th month IU)
Unites with the shaft around 20 years of age
• Head (1st year)
• Greater trochanter (4th year)
• Lessor trochanter (12th year)
Upper three fuses with the shaft around
18 years of age
NECK OF THE FEMUR
Trochanteric anastomosis
1. Superior gluteal artery
2. Inferior gluteal artery
3. Medial circumflex femoral
artery
4. Lateral circumflex femoral
artery
From this anastomosis, there
are small arteries called
“Retinacular arteries” supply
the NOF and the head
“Artery of ligament of head”
supplies blood to the head of
femur for some extent.
FRACTURE NECK OF THE FEMUR
Fracture of the neck may occur very
close to the head of the femur
(subcapital fracture), near the
midpoint (cervical fracture) or very
close to the shaft (basal)
Subcapital fracture is common in old
age because the spongy bone of the
neck is atrophic and the cortical bone
is thinner.
In case the fracture is complete it
interrupts the blood vessels passing
in the retinacula to the head of the
femur.
The vessels in the round ligament of the head are insufficient to prevent
‘avascular necrosis’.
FRACTURE NECK OF THE FEMOR
Non-union may be due to the effect of the synovial fluid which bathes the
fractured fragments and inhibits osteogenesis.
When the fracture of the neck is close to the shaft it is partly intracapsular and
partly extracapsular and union is better than the subcapital fracture.
In case the fracture is not impacted the following deformity is present
a. There is a definite (true) shortening of the limb because the distal fragment
is pulled upward by the rectus femoris, the adductors and the hamstrings
with overlap of the two fragments.
b. The distal fragment is also laterally rotated by the lateral rotators which are
stronger than the medial rotators.
FRACTURE SHAFT OF THE FEMUR
(Just below the lesser trochanter)
The following deformity is produced
Proximal fragment
• Abducted by the gluteus medius and
minimus.
• Laterally rotated by the gluteus
maximus, piriformis, obturators and
quadratus femoris.
• Flexed by the iliopsoas which is
attached to the lesser trochanter.
Distal fragment
• Pulled upward behind the proximal
fragment by the hamstrings and the
quadriceps femoris
• Adducted and laterally rotated by the
adductors
FRACTURE SHAFT OF THE FEMUR
(At its middle third)
The distal fragment is
drawn upward to a great
extent behind the
proximal fragment (much
overlap) by the
quadriceps and the
hamstrings, thus
resulting in considerable
shortening
FRACTURE SHAFT OF THE FEMUR
(Supracondylar)
Distal fragment
Drawn backward by the pull of the 2
heads of the gastrocnemius.
So it may injure the popliteal artery
as it lies in direct contact with the
popliteal surface of the femur.
Pulled upward behind the proximal
fragment by the hamstring muscles.
(biceps femoris, semimembranosus and
ischial part of the adductor magnus)
Similarly ‘Slipped epiphysis’ may also
cause injury to popliteal artery
PATELLA
Patella is the largest sesamoid bone in the body
Lies within the tendon of quadriceps femoris
PATELLA
The stability of the patella is
maintained by
• Superiorly by quadriceps
• Inferiorly by patellar ligament
• Medially by horizontal fibers of
vastus medialis
• Laterally by prominent lateral
condyle of femur
PATELLA DISLOCATION
Due to twisting nature of sports, the
patella can come out of joint with an
awkward twist of the femur on tibia.
A twisting motion causes the patella to
shift to the side. Usually, the patella
moves laterally.
Because the quadriceps muscle
contracts to maintain the stability of the
body.
The shin has shifted so that the line of
pull of the quadriceps causes the patella
to shift laterally.
The patella is pulled laterally because it
wants to remain in line with the muscle.
PATELLA DISLOCATION
Is it common in women?
Females seem to have a greater risk for patellar dislocations than males.
This may be due, in part, to the shape of their hips.
A female’s hips are shallower and wider to accommodate pregnancy.
This tends to cause genu valgum (“knock-kneed” appearance)
in other words, their knees are closer together than their ankles like in
the above example.
PATELLA FRACTURE
Two major mechanisms of injury, direct and indirect.
Direct
Direct blow during fall onto knee or when it hits dashboard in RTA.
Because of small amount of prepatellar soft tissue and direct contact with the
femur posteriorly, nearly all of force is delivered to patella.
Frequently causes considerable comminution, but often there is little
displacement of fractured fragments.
Indirect
Can be due to jumping or unexpectedly rapid flexion of the knee against fully
contracted quadriceps.
Fractures of this type tend to be less comminuted than those from direct
trauma, but they are displaced and are often transverse.
PATELLA FRACTURE
FRACTURE OF TIBIA AND FIBULA
In case of fracture of only one bone
there is little displacement because
the intact bone acts as a splint.
In fracture of both bones, the distal
fragments are drawn upward behind
the proximal fragments by the action
of the gastrocnemius and soleus
muscles
Fractures of tibia commonly to be
open because the medial surface is
subcutaneous throughout the course.
The nutrient artery to the tibia is directed towards the lower end.
Therefore, it may be torn in fracture of the distal 1/3 of the tibia resulting in
ischaemic necrosis with delayed union or non-union.
FRACTURE IN DISTAL END OF THE LEG
These fractures are very common and result from indirect violence with the
following possibilities.
•
The lateral malleolus may be fractured alone.
•
Both the medial malleolus and the lateral malleolus may be fractured
together (Pott’s fracture).
•
The talus may be thrust upward between the tibia and fibula
(Dupuytren’s fracture).
It is associated with high fibular
fracture and disruption of syndesmosis
FRACTURE IN DISTAL END OF THE LEG
Pott’s fracture
A fracture to the lateral or medial
malleoli is known as Pott's fracture
In severe ankle sprains the force may
pull the bone off with the ligament.
This injury will occur when the ankle is
rolled inward or outward beyond its
normal range of movement.
Specially forcible eversion of the ankle
Symptoms include
• Severe pain
• Unable to put weight on the injured leg and the ankle will feel unstable
• Tenderness at the point of the fracture, usually over malleoli.
FRACTURES OF THE FOOT
Metatarsal stress fractures
• Takes place in the distal 1/3 of metatarsal
bones (MTB)
• These occur as the result of applied load to
the bone in an amount, or at a rate, that is
greater than the ability of the bone to repair
and heal itself.
• MT stress fractures are also known as
march fractures.
• MT stress fractures are most commonly seen in the 2nd and 3rd MTB.
• Stress fractures of the 4th and 5th MTB are rare and least on1st MTB.
• Minimal displacement due to the attachment of the interosseous muscles
that act as a splint.
End of the Clinical Anatomy Lecture I
LOWER LIMB
FRACTURES AND DISLOCATIONS
Thank you...