Bones - Femur Flashcards
Proximal femur
Bony landmarks?
Associated muscles and ligaments?
1) Head - articulates with the acetabulum to form hip joint - smooth surface covered with articular cartilage (except for a small depression, the fovea), where the ligamentum teres attaches.
2) Neck - connects head to shaft - cylindrical - set at an angle 135 degrees away from the shaft - this allows for greater movement at the hip joint.
3) Greater trochanter - most lateral palpable projection - site of attachment of many muscles - gluteus medius, gluteus minimus, piriformis. Vastus lateralis originates here.
4) Lesser trochanter - projects from the posteromedial side - site of attachment of the iliopsoas - forceful contraction causes avulsion fracture of the lesser trochanter.
5) Intertrochanteric line - ridge of bone that runs inferomedially from the greater trochanter. After it passes the lesser trochanter, it is known as the pectineal line. Site of attachment of the iliofemoral ligament (strongest ligament of the hip joint).
6) Intertrochanteric crest - ridge on posterior surface of femur - runs between greater and lesser trochanters - quadrate tubercle on its superior half where the quadratus femoris attaches.
Clinical relevance: proximal femur fractures?
Neck of femur fractures - increasinly common and tend to be sustained in elderly population as a result of low energy falls in the presence of osteoporotic bone.
More prevalent in women.
Can occur in younger people in high energy accidents.
Classified into two groups:
1) Intercapsular - occurs within the capsule of the hip joint. Can damage the medial femoral circumflex artery. This can cause necrosis of the femoral head.
2) Extracapsular - the blood supply is intact, therefore avascular necrosis of the head is unlikely.
The Shaft?
Bony landmarks?
Descends in the slight medial direction - brings the knees closer to the centre of the gravity.
Cross-section is circular but flattened in the proximal and distal ends.
Posterior surface - linea aspera (roughened line) - splits distally to form the medial and lateral supracondylar lines. The flat popliteal surface lies between them.
Proximally, the medial supracondylar line is called the pectineal line. The lateral supracondylar line is called the gluteal tuberosity.
Distally, the medial supracondylar line terminates at the adductor tubercle, where the adductor magnus attaches.
Clinical relevance: fractures of the femoral shaft?
Typically result from high energy injuries. Can occur in elderly in low energy injuries.
Often causes a spiral fracture, which causes leg shortening. This is due to the bony fragments overriding, pulled by their attached muscles.
As it usually results from high energy injuries, soft tissue damage may also be damaged - neurovascular structures, such as the femoral nerve and artery may be damaged.
A closed femoral shaft fracture may result in considerable haemorrhage (1000-1500ml).
Distal femur
Bony landmarks?
1) Medial and lateral condyles - rounded areas at the end of the femur. Posterior and inferior surfaces articulate with the tibia and menisci of the knee. Anterior surface articulates with the patella. The prominent lateral condyle helps prevent natural lateral movement of the patella. a flatter condyle is more likely to cause a patella dislocation
2) Medial and lateral epicondyles - bony elevations of the non-articular surfaces of condyles. Medial epicondyle is larger.
3) Intercondyle fossa - posterior surface of the femur - located between the two condyles - contains two facets for attachment of intracapsular knee ligaments; the anterior cruciate ligament (ACL) (medial aspect) and the posterior cruciate ligament (PCL). to the lateral aspect of the medial condyle.
