Clinical Anatomy Lecture I

LOWER LIMB 

FRACTURES AND DISLOCATIONS

Dr Vindye R WalpolaLecturer 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)

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)

FEMUR

Upper three fuses with the shaft around 18 years of age

Trochanteric anastomosis

1. Superior gluteal artery

2. Inferior gluteal artery

3. Medial circumflex femoral artery

4. Lateral circumflex femoral artery

NECK OF THE FEMUR

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 is the largest sesamoid bone in the body Lies within the tendon of quadriceps femoris

PATELLA

The stability of the patella is maintained by

PATELLA

• Superiorly by quadriceps

• Inferiorly by patellar ligament

• Medially by horizontal fibers of vastus medialis

• Laterally by prominent lateral condyle of femur

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?

PATELLA DISLOCATION

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.

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

PATELLA FRACTURE

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.

FRACTURE OF TIBIA AND FIBULA

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.

These fractures are very common and result from indirect violence with the following possibilities.

FRACTURE IN DISTAL END OF THE LEG

• 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

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

FRACTURE IN DISTAL END OF THE LEG

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.

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.

FRACTURES OF THE FOOT

• 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...