Identifying Bones of the Lower Extremities - Anatomy

Long bones have a body that is longer than it is wide (such as the femur, humerus, and phalanges), with growth plates (epiphysis) at either end. The have a hard outer surface of compact bone and a spongy interior known as cancellous bone (contains bone marrow). Both ends of the bone are covered in hyaline cartilage to help protect the bone and decrease friction.

The calcaneus is the heel bone and generally strikes the ground first in a normal walking gate. It is the most posterior bone in the foot. The achilles tendon attaches to it posteriorly.

The popliteal fossa is part of the femur. The lateral supracondylar line is also part of the femur. The soleal line is part of the tibia. The the subclavian groove is part of the clavicle and is an attachment site for the subclavius muscle.

The third cuneiform articulates with the navicular, second cuneiform, cuboid, and second, third, and fourth metatarsals.

The leg is the section of the lower limb distal to the knee cap. The two bones of the leg are the tibia and fibula. The fibula is located posterolateral to the tibia, making the tibia the more anterior of the two.

The femur is located in the thigh, and the ilium forms part of the pelvis. These are both located proximal to the leg.

The coxal bone, also known as the pelvis, is composed of three main regions: the ilium, ischium, and pubis. The ilium is the most superior of these structures, forming the iliac crests that serve as the origin and insertion for several muscles. The ischium and pubis are inferior to the ilium and join together to form the obturator foramen, with the ischium posterior to the pubis. The acetabulum is the smooth depression, or fossa, in the hip bone where the head of the femur sits. The ilium, ischium, and pubis all come together to form the acetabulum.

The coccyx is also known as the tailbone, and is an extension of the spinal column.

The cuboid does not articulate with the talus.

The calcaneus articulates with the talus to form the subtalar joint. The ankle joint is formed by the articulation of the talus with the tibia and fibula and is commonly injured as well in compression type injuries (usually a plafond fracture). The navicular articulates with the talus anteromedially.

Anatomical definitions determine the thigh to be the region between the knee and hip, and the leg to be the region between the knee and ankle. The thigh houses the femur, while the leg houses the tibia and fibula. The fibula articulates with the talus, one of the seven bones found in the ankle, at its distal end and the femur at its proximal end. This distal articulation is part of the ankle joint, while the proximal articulation is part of the knee joint.

The tibia is the larger bone of the two, and is responsible for carrying the majority of the weight of the lower limb.

A bone marrow biopsy is a procedure involving the removal of the fluid and a sample of bone from the marrow found at the center of some bones in the body. Aspiration, on the other hand, is only the removal of the fluid. The sample is acquired through a needle under anesthesia. The sample contains red blood cells, white blood cells, and platelets, which can be observed under a microscope for abnormalities in numbers and shape. The results can also be used to look for spread of infection into the bone, as well as cancer.

The most common places for obtaining a sample in an adult are flat bones, namely the sternum and pelvic girdle. In children, the femur is a first choice. It is a long bone and is a major site of hematopoiesis in individuals younger than the age of 18.

The seven tarsal bones, including the three cuneiform bones, form the posterior of the foot immediately distal to the heel. Together with the five metatarsals and the fourteen phalanges, these twenty-six bones allow for the tremendous distribution of force necessary for bipedal locomotion.

Moving proximal-to-distal (away from the body's core, towards the end of the foot), the order of bones is the femur (thigh), tibia (leg), tarsals (foot bones close to ankle), metatarsals (foot bones far from ankle).

To remember the names of the tarsals, use the following mnemonic: Tiger Cubs Need MILC: Talus Calcaneus Navicular Medial Cuneiform Intermediate Cuneiform Lateral Cuneiform Cuboid. The scaphoid is carpal, all the others are a tarsals.

Each of these are features of the femur except the malleolus. That is a feature of the tibia and fibula. The linea aspera is located along the posterior surface of the femur. The femur has a medial and a lateral condyle at its distal end. The patellar surface articulates with the patella.

The correct answer is the tibia. While the distal ends of the fibula and tibia connect the knee to the ankle at the talocrural hinge joint, it is the tibia that is "weight-bearing" and one can see that it bears the majority of the weight by the way it aligns with the femur. It is also the thicker than the fibula. The talus is the lower ankle bone whose proximal end articulates with the distal ends of the tibia and fibula. Again, its articulation with the tibia bears more weight than it does with fibula. The calcaneus is the heel bone or the part of your foot you might want to karate kick with. The femur is not in the lower leg.

Sesamoid bones are located in tendons or joint capsules. They reduce friction, increase the force the tendon can pull, and/or maintain the shape of tendons when they are taut. The largest sesamoid bone in the body is the patella. The pisiform is also a sesamoid bone, but is much smaller than the patella and is located in the wrist. The scaphoid and hamate are located in the wrist, but are not sesamoid.

The tibial tuberosity can be felt just inferior to the knee on the anterior side of the leg. The olecranon is also known as the elbow, and is part of the ulna. The lateral condyle is the insertion point for the biceps femoris, and cannot be palpated through the skin. The soleal line is on the posterior surface of the tibia, and is thus not palpable through the skin.

The bone that forms the shin is the tibia. This is palpable along the anterior surface of the lower limb. The fibula is also located in the lower leg, but is not part of the prominent ridge felt on the front of the leg, as it is deep. The femur is the bone found in the thigh. The mandible is the jaw bone.

Sesamoid bones form inside tendons and/or muscles. They help ease the movement of a tendon past the bone, prevent deformation when the tendon is taut, and can also increase the force the tendon can pull by acting like a pulley. Examples of sesamoid bones are the patella in the knee and the sesamoid bones of the foot.

The metacarpals are analogous to the metatarsals of the foot and make up the body of the hand between the wrist and the projection of the fingers. The carpals are the eight wrist bones. The tarsals and metatarsals make up the ankle and the body of the foot, respectively. The phalanges are the bones of the fingers and toes.