Femur Location: The femur bone is the toughest and longest bone in the body, employing the location of the lower limb, between the hip and knee joints. The femur figure is so exclusive that it makes the bone satisfactory for bolstering the numerous muscular and ligamentous connections within this zone, in addition to maximally stretching the limb during ambulation. Proximally, the femur links with the pelvic bone. Distally, it cooperates with the patella and the proximal prospect of the tibia.
The femur starts to evolve between the 5th to 6th gestational week by the path of endochondral ossification (where a bone is composed using a cartilage-depended foundation). While several ossification places (points of bone development) emerge went through intrauterine life, the bone continues to advance through childhood and early boyhood. Ossification of the femur is finished between the 14th and 18th years of life.
Its operations as the location of origin and connection of many muscles and ligaments and can be divided into three parts; proximal, shaft, and distal.
This article will analyze the gross anatomy of the femur. It will also consider the blood supply of the femur and summarize the points of muscular and ligamentous connections. Additional analysis of clinical examination and disorders of the femur is also included.
The femur is the lengthiest bone in the human body. Many agree that it is also the strongest (the jaw bone is the other contender). The two femur bones serve as pillars in our legs that allow us to walk, run, jump, and make all kinds of other movements.
There are five kinds of bones – long bones, short bones, irregular bones, sesamoid bones, and flat bones. The femur bone is a long bone. Long bones are probably the kind most people guess of when we visualize what a bone should look like. This kind of bone is long and thin and they vary in size from the largest bone in the human body (the femur) to a much smaller version in your fingers and toes called phalanges. The long bone’s primary function is as the major support system of the body and as a movement facilitator.
The femur is located, as the general term for it suggests, in the thigh or upper section of the leg and it goes from the hip to the knee. The proximal end of the bone, the section that is located nearest to the hip, has the femoral head that helps to form the joint within the hip. The distal end of the femur is located nearest to the knee.
Femur Bone Parts: Proximal
The proximal prospect of the femur links with the acetabulum of the pelvis to form the hip joint.
It subsists of a head and neck, and two bony processes – the greater and lesser trochanters. There are also two bony ridges linking the two trochanters; the intertrochanteric line anteriorly and the trochanteric crest posteriorly.
- Head – links with the acetabulum of the pelvis to form the hip joint. It has a smooth surface, protected with articular cartilage (except for a tiny depression – the fovea – where ligamentum teres joints).
- Neck – joints the head of the femur with the shaft. It is cylindrical, projecting in a superior and medial direction. It is set at an angle of roughly 135 degrees to the shaft. This angle of projection permits a wider range of movement at the hip joint.
- Greater trochanter – the most lateral palpable projection of bone that originates from the anterior aspect, just lateral to the neck.
- It is the location of connection for many of the muscles in the gluteal region, such as gluteus medius, gluteus minimus, and piriformis. The vastus lateralis originates from this location.
- An avulsion fracture of the greater trochanter can materialize as a result of the forceful recession of the gluteus medius.
- Lesser trochanter – smaller than the greater trochanter. It tasks from the posteromedial side of the femur, just inferior to the neck-shaft junction.
- It is the location of connection for iliopsoas (a forceful recession of which can cause an avulsion fracture of the lesser trochanter).
- Intertrochanteric line – a ridge of bone that runs in an inferomedial direction on the anterior surface of the femur, spanning between the two trochanters. After it passes the lesser trochanter on the posterior surface, it is known as the pectineal line.
- It is the location of the connection for the iliofemoral ligament (the strongest ligament of the hip joint).
- It also serves as the anterior connection of the hip joint capsule.
- Intertrochanteric crest – like the intertrochanteric line, this is a ridge of bone that connects the two trochanters. It is located on the posterior surface of the femur. There is a rounded tubercle on its superior half called the quadrate tubercle; where quadratus femoris attaches.
Femur Bone Parts: Shaft
The femoral shaft is a cylindrical structure with significant variability from one individual to another. The shaft is relatively wide at the proximal end but becomes progressively narrow toward the middle. It is bowed anteriorly, which contributes to the weight-bearing capacity of the bone. The shaft then undergoes marked re-expansion towards the distal end. Anteriorly, the shaft is smooth and devoid of distinguishing features. However, the posterior surface is more rugged as it facilitates the connections of the large muscles of the thigh.
Although it is described as being a cylindrical structure, the shaft of the femur has several surfaces and borders that blend seamlessly. Toward the middle of the shaft, there are three surfaces and three borders. The convex anterior surface is bound by medial and lateral rounded borders. There is a posterolateral surface which is limited anteriorly by the lateral border and posteriorly by the Linea Aspera. There is also a posteromedial surface that is limited by the medial border anteriorly and by the linea Aspera posteriorly.
There is a so-called third tuberosity in the form of the gluteal tuberosity. While it is not a true tuberosity, it may be large enough to be considered as such. It is rough and elongated along the long axis of the shaft; on the proximal posterior surface of the femur. The groove is continuous with the lateral lip of the linea Aspera. On the medial, proximal, posterior part of the femur is another (smaller ridge) known as the pectineal line. It acts as the point of connection for the pectineus muscle.
The most pronounced part of the posterior surface is the Linea Aspera. This is a raised longitudinal impression that runs along the long axis of the femur. It is made up of a medial and a lateral lip; the former originating near the lesser trochanter, and the latter arising from the greater trochanter. The medial and lateral lips unite along with the middle third of the femoral shaft, traveling medial to the nutrient foramen.
The linea aspera then diverges toward the distal third of the femur where the medial and lateral lips become continuous with their respective ipsilateral supracondylar line (medial and lateral supracondylar lines). The medial supracondylar line continues to the adductor tubercle (on the medial condyle) and the lateral supracondylar line ends at the lateral condyle.
The popliteal surface of the femur is a triangular space found at the distal posterior surface of the femur. It is bordered medially and laterally by the corresponding supracondylar lines, and inferiorly by the superior border of the fibrous capsule of the knee. The caudal aspect of the surface forms part of the floor of the popliteal fossa.
Femur Bone Parts: Distal End
The distal end of the femur is characterized by the presence of the medial and lateral condyles, which articulate with the tibia and patella to form the knee joint.
- Medial and lateral condyles – rounded areas at the end of the femur. The posterior and inferior surfaces articulate with the tibia and menisci of the knee, while the anterior surface articulates with the patella. The more prominent lateral condyle helps prevent the natural lateral movement of the patella; a flatter condyle is more likely to result in patellar dislocation.
- Medial and lateral epicondyles – bony elevations on the non-articular areas of the condyles. The medial epicondyle is the larger.
- The medial and lateral collateral ligaments of the knee originate from their respective epicondyles.
- Intercondylar fossa – a deep notch on the posterior surface of the femur, between the two condyles. It contains two facets for connection of intracapsular knee ligaments; the anterior cruciate ligament (ACL) attaches to the medial aspect of the lateral condyle and the posterior cruciate ligament (PCL) to the lateral aspect of the medial condyle.
Function and working of Femur
Humans are bipedal organisms–meaning that they are able to walk on two legs. The distribution of the weight of the organism is important in order to prevent trauma to supporting structures. The relationship of the femur with its proximal and distal articulations is rather unique.
Firstly, the neck of the femur is angled superomedially in order to fit into the acetabulum. An ideal angle between the inferior margin of the femoral neck and the medial surface of the femoral shaft should be between 120 and 130 degrees.
This angle of inclination ensures that the weight of the upper body passes along the mechanical axis of the femur. This axis can be identified by drawing a vertical line from the center of the femoral head to the center of a horizontal line across the tibial plateau (the center of the knee joint line).
Note: The mechanical axis of the femur differs from the anatomical axis of the femur (a line running from the center of the greater trochanter, along the femoral shaft, and ending at the center of the knee joint line).
The angle between the mechanical and anatomical axes of the femur is about 8 degrees. However, an extreme variation of the angle of inclination could change this relationship and increase the amount of stress across the neck of the femur. The tibia also has a mechanical axis (the mechanical axis of the tibia) which runs from the knee joint line to the center of the ankle joint.
Both femurs naturally converge towards the knee. This degree of convergence is measured and recorded as the angle of convergence. Variation in the angle of convergence impacts the angle between the lateral aspects of the tibia and femur (the femoral-tibial angle, which is roughly 175 degrees).
This measurement can be used as a surrogate for the gold standard for assessing the axial alignments, which is the hip-knee-ankle angle. Consequently, any extreme variation from this angle (such as those seen in varus and valgus deformities) will result in malalignment of the mechanical axes of the respective bones.
Over time, the malalignment can result in the destruction of the joint surfaces and the progression of osteoarthritis.
Complications with broken Femurs
Complications can arise with femur breaks.
- Proper setting- If the femur is not set properly, there’s a chance the leg will become shorter than the other one and may cause hip or knee pain many years later. Poor alignment of the femur bone may also be painful.
- Peripheral damage- The break may also injure the muscles, tendons, ligaments, and nerves of the leg.
Surgical complications. Some complications related to surgery include infection and blood clots.
Managing a broken femur after surgery
Following a femur break, once the bone is set back into its proper place and is stable, your doctor will most likely recommend physical therapy to strengthen the muscles around the bone. Exercises to strengthen the thigh will also help with the return to flexibility and normal function of the leg.
A broken femur will usually have a major effect on your life, but only temporarily. Surgeries are routinely effective and people are typically able to completely heal from a broken femur. In the majority of broken femurs, patients return to a normal lifestyle.