femur

Bone: Femur
Anterior view of the femur
Latin	os femoris, os longissimum
Gray's	subject #59 242
Origins	Gastrocnemius , Vastus lateralis, Vastus medialis, Vastus intermedius
Insertions	tensor fasciae latae, gluteus medius, gluteus minimus, Gluteus maximus, Iliopsoas
Articulations	hip: acetabulum of pelvis superiorly knee: with the tibia and patella inferiorly
MeSH	Femur

The femur (pl. femurs or femora), or thigh bone, is the most proximal (closest to the center of the body) bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in the rear legs. The femur is the largest bone in the body. The head of the femur articulates with the acetabulum.

In humans

In human anatomy, the femur is the longest and largest bone in the body. The average adult male femur is 48 centimeters (18.9 in) in length and 2.8 cm (1.1 in) in diameter at the mid-shaft, and has the ability to support up to 30 times the weight of an adult.^[1] The femur forms part of the hip joint (at the acetabulum) and part of the knee joint, above which it is located. There are four eminences, or protuberances, in the human femur: the head, the greater trochanter, the lesser trochanter, and the lower extremity. They appear at various times from just before birth to about age 14. Initially, they are joined to the main body of the femur with cartilage, which gradually becomes ossified until the protuberances become an integral part of the femur bone, usually in early adulthood.

The shaft of the femur is cylindrical and has a rough line, the linea aspera, on its posterior surface.

The intercondylar fossa is present between the condyles at the distal end of the femur. In addition to the intercondylar eminence on the tibial plateau, there is both an anterior and posterior intercondylar fossa (area), the sites of anterior cruciate and posterior cruciate ligament attachment, respectively.

Other species

In primitive tetrapods, the main points of muscle attachment along the femur are the internal trochanter and fourth trochanter, and a ridge along the ventral surface of the femoral shaft referred to as the adductor crest. The neck of the femur is generally minimal or absent in the most primitive forms, reflecting a simple attachment to the acetabulum. The greater trochanter was present in the extinct archosaurs, as well as in modern birds and mammals, being associated with the loss of the primitive sprawling gait. The lesser trochanter is a unique development of mammals, which lack both the internal and fourth trochanters. The adductor crest is also often absent in mammals or alternatively reduced to a series of creases along the surface of the bone.^[2]

Some species of whales^[3], snakes, and other non-walking vertebrates have vestigial femurs.

One of the earliest known vertebrates to have a femur is the Eusthenopteron, a prehistoric lobe-finned fish from the Late Devonian period.

In invertebrates, the name femur tite is given to the most proximal full-length jointed segment of the legs of some arthropods such as spiders.

Fractures

A femoral fracture that involves the femoral head, femoral neck or the shaft of the femur immediately below the lesser trochanter may be classified as a hip fracture, especially when associated with osteoporosis.

Etymology

In medical Latin the genitive form of femur is always femoris, but in classical Latin the genitive is often feminis, and should not be confused with case forms of femina, which means "woman".

Additional images

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  Knee diagram

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  Upper extremity of right femur viewed from behind and above.

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  Right femur. Anterior surface.

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  Right femur. Posterior surface.

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  Left hip-joint, opened by removing the floor of the acetabulum from within the pelvis.

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  Right knee-joint. Posterior view.

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  Left knee-joint from behind, showing interior ligaments.

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  Sagittal section of right knee-joint.

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  Capsule of right knee-joint (distended). Lateral aspect.

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  Capsule of right knee-joint (distended). Posterior aspect.

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  Cross-section through the middle of the thigh.

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  Deep muscles of the medial femoral region.

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  Posterior view.

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  Anterior view.

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  Superior epiphysis - anterior view

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  Superior epiphysis - posterior view

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  Inferior epiphysis - posterior view

References

External links

Look up femur or thighbone in Wiktionary, the free dictionary.

• Image with major components labeled at v
• Cross section at UV pembody/body18b