Lower Limb


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The femur is the longest bone in the body and the only bone in the thigh.

Gross Anatomy



The femur develops from the mesoderm and ectoderm in the limb buds. The primary centre in the shaft ossifies at 7-8weeks in utero, and fuses at 16-18 years old. The secondary ossification centres are at the distal physis (ossifies at birth, fuses age 19), head (ossifies at 1year, fuses at 18 years), greater trochanter (ossifies at 4-5 years, fuses at 16 years) and lesser trochanter (ossifies at 10years, fuses age 16).




The head, neck, greater and lesser trochanters are located proximally. The neck is comprised of tensile and compressive groups of trabeculae. The head has a fovea for the attachment of ligamentum teres. On the anterior surface, the intertrochnteric line is where the fibrous capsule attaches. Posteriorly the capsule attaches more proximally on the neck. The 2 femoral condyles, medial and lateral, are located distally. The lateral condyle projects more anteriorly and proximally. The medial condyle is larger, more posterior and distal. The femoral anteversion is usually 12-14 degrees. The normal neck-shaft angle is 126 degrees. The anatomical axis is along the shaft of the femur. The mechanical axis is from the femoral head to the intercondylar notch. The shaft of the femur descends 7degress medially in the coronal plane. The mid femur is triangular shape in cross-section. Along the posterior aspect of the shaft proximally is the gluteal tuberosity and more distally the linea aspera.




Hip joint: Proximally the femoral head articulates with the pelvic acetabulum forming the hip joint. This is a synovial ball and socket type joint. The acetabulum is deepened and stabilised by the labrum. The transverse acetabular ligament runs from anteroinferior to posteroinferior acetabulum.

The ligaments involved in the joint capsule are: pubofemoral, iliofemoral, ischiofemoral and zona orbicularis. The strongest of these is the iliofemoral ligament.

Knee joint: Distally the femoral condyles articulate with the tibia to form the knee joint.


Blood supply


Blood supply to the head and neck comes from the retinacular branches of the medial and lateral circumflex arteries (branches off profunda). The shaft is supplied by the nutrient artery which is a branch of profunda femoris artery. The blood supply to the head and neck of femur is tenuous and retrograde. This leads to an increased risk of avascular necrosis in intracapsular neck of femur fractures.


Ligamentous attachments


Greater trochanter:

§  Piriformis (insertion)

§  Obturator interus (insertion)

§  Superior gemellus (insertion)

§  Gluteus medius (insertion)

§  Gluteus minimus (insertion)

Lesser trochanter:

§  Ileopsoas (insertion)

Linea aspera:

§  Adductor magnus (insertion)

§  Adductor longus (insertion)

§  Adductor brevis (insertion)

§  Biceps femoris (origin)

§  Pectineus (insertion)

§  Gluteus maximus (insertion)

§  Vastus lateralis (origin)

§  Vastus medialis (origin)

Adductor tubercle:

§  Adductor magnus (insertion)


Clinical Anatomy

Femoral neck fractures:


Either low energy fractures in the elderly oseoporotic patients, or high energy injuries in the young.

Can be divided into intracapsular or extracapsular fractures

Intracapsular fractures have a higher risk of interrupting the blood supply to the femoral head, leading to avascular necrosis. Intracapsular fractures can be classified according to the Garden classification:

§  1  = valgus impacted/ incomplete

§  2 = non-displaced

§  3 = partially displaced

§  4 = displaced

The fracture pattern and patient factors dictate the choice of surgical management.


Hip dislocation:


Caused by high energy trauma and often have multiple associated injuries.

85% are posterior dislocations. In this case the thigh will be adducted, flexed and internally rotated.

Early reduction is essential

Complications include: avascular necrosis, sciatic nerve injuries (posterior), femoral artery and nerve injury (anterior), instability, osteoarthritis, heterotopic ossification


Femoral shaft fracture:


High energy injury and a potential source of significant blood loss.


Perthes disease:


Osteonecrosis of the femoral head of idiopathic or vascular etiology.

Usually presents in boys aged 4-8 years with unilateral thigh or knee pain and limp.


Slipped upper femoral epiphysis (SUFE)


Usually presents in obese 11-14 year olds with hip, thigh or knee pain and limp.

Quick Anatomy

Key Facts







7-8 wks in utero



Distal physis






Greater trochanter



Lesser trochanter




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The femur is a long bone, with multiple muscle attachments. The main pathology occurs because the femoral neck weakens with age leading to an increased susceptibility to fracture.


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