The femur is the longest long bone of the human skeleton and is also known as the femur in the medical field. Anatomically, it can be divided into several sections and plays a major role in locomotion. Therefore, occurring diseases in this area are all the more drastic.
What is the femur?
Due to its high density, the thigh bone (the femur) has very high stability and strength. It is the strongest bone in the human articular system and forms the bony foundation of the thigh. Like all long bones, the femur has a medullary cavity with associated bone marrow. As part of the lower limb, the longest long bone in the body interacts directly with the lower leg and the knee joint. Through the hip joint, the femur connects to the pelvis. The femur is divided into the anatomical sections of the head of the femur, the neck of the femur, the shaft of the femur, and the lower end of the long bone. In addition, the femur forms the origin and attachment for a variety of muscles.
Anatomy and structure
The entire femur consists of a solid protective layer and a filled cavity, which is filled with soft tissue made of blood cells. As the name suggests, the head of the femur is located at the top of the long bone. The head of the femur has a spherical structure and, together with the acetabulum of the pelvis, forms the hip joint. The femoral head is supplied with blood by an artery that is securely enclosed by the femoral head fossa. The femoral head is directly connected to the femoral neck, which is at 127° to the femoral shaft in adult humans. At the tip of the femoral neck are two rolling hills. While the large rolling mound is anatomically located on the outside, the small rolling mound is placed on the inside. Both rolling hills serve as the starting point for large muscle groups such as hip flexors or arm spreaders. Directly below the femoral neck is the cylindrically shaped femoral shaft, on the back of which is the so-called rough line. It serves primarily as an attachment point for various muscle groups. The rough line, also called the linea aspera, is itself divided into two groins. These two groins diverge at the upper and lower ends of the femoral head and do not converge again until they reach the middle of the bone. Together with the tibia, the two lower femoral rolls form the knee joint. The lower end of the femur is divided into two articular cartilages, which, in contrast to the femoral shaft, are strongly thickened. Furthermore, they have an outward curvature. Between the two articular cartilages, which are separated from each other, is the cruciate ligament cavity, which in turn makes contact with the kneecap.
Function and tasks
As the largest bone in the human musculoskeletal system, the femur performs important functions in the body. Together with the acetabulum of the pelvis, the head of the femur forms the hip joint. The latter is anatomically a large ball and socket joint. Furthermore, the lower articular surfaces of the femur form the basis for the kneecap. Primarily, the main function of the femur is to form the knee and hip joints. In addition, the spiral course of the joint surfaces relaxes the collateral ligaments during flexion in the knee joint, allowing internal and external rotation of the lower leg. Standing upright and walking as well as locomotion in steps would not be possible without the perfect interaction of bones and joints. Since the thigh consists of only a single bone, it is particularly important that this bone is stable and load-bearing. Due to its robust consistency, the femur is able to transfer the existing body force from the pelvis to the lower limbs. In the area between the femoral shaft and neck, there is a larger and a smaller rolling mound on the back of the femur, which serve the attachment of the muscles.
Diseases
The most common complaints, dysfunctions, or limitations result from the anatomical structure as well as daily stress during locomotion. Due to the high stress, the femur is particularly affected by wear and tear diseases.The joint surfaces and articular cartilages of the femur are most susceptible to signs of wear and inflammation. Not only daily exercise, but also congenital deformities of the joint apparatus, such as hip dysplasia, can lead to premature wear of the femur. Painful discomfort, restricted mobility or even complete immobility are usually caused by osteoarthritis of the knee joint or osteoarthritis of the hip joint at an advanced age. If the arthritic changes cannot be remedied by conservative therapy, the only option left to those affected is joint replacement. In older people, serious falls resulting in a fracture of the neck of the femur are not uncommon. As bone density decreases with age, there is a risk of fracture between the femoral head and neck even during light physical activity. Fractures in this area usually require surgery. Another femur fracture that typically occurs in old age is the femur fracture near the knee. These are fractures above the joint rolls. Once the femur is fractured, the healing process proves to be extremely difficult and fraught with complications. A rather rare fracture of the femur is the femoral shaft fracture. This type of femur fracture is only possible with the greatest use of force. Statistically, the most common reason for a femoral shaft fracture is a car accident in which strong mechanical forces are applied to the bone.
