The femur, also known as the thigh bone, is the longest bone of the human skeleton and is located between the hip bone and the knee.LEARNING OBJECTIVE Describe the femur

KEY POINTS The femur is one of the strongest bones in the human skeleton. It functions in supporting the weight of the body and allowing motion of the lower extremity. The femur makes up part of the hip joint and thekneejoint.

TERM condyleA smooth prominence on a bone where it forms a joint with another bone.Give us feedback on this content:FULL TEXTThe femur, or thigh bone, is the most proximal (closest to the center of the body) bone of the leg intetrapodvertebrates 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 head of the femur articulates with the acetabulum in the pelvic bone to form the hip joint, while thedistalpart of the femur articulates with thetibiaandpatellato form the knee joint. By most measures, the femur is the strongest bone in the body.

Anterior Position of the Human FemurThe femurs are outlined in red.The femur is the longest bone of the human skeleton and is located between the hip bone and the knee. It is the only bone in the thigh. This bone is also one of the strongest bones in the human skeleton. It functions in supporting the weight of the body and allowing motion of the lower extremity.The head (at the proximal extremity) of the femur articulates with the acetabulum of thepelvisto form the hip joint . The lower extremity of the femur (or distal extremity), which is larger, is somewhat cuboid in form and consists of two oblong eminences known as thecondyles. The articular surface of the lower end of the femur occupies the anterior, inferior, andposteriorsurfaces of the condyles. The front or anterior portion is the patellar surface and articulates with the patella. The lower and posterior parts articulate with the corresponding condyles of the tibia to form the knee joint.

FemurThe anterior surface of the femur with parts labeledThe lower and posterior parts of the articular surface constitute the tibial surfaces forarticulationwith the corresponding condyles of the tibia and menisci.

The patella, also known as the knee cap, is a triangular shaped bone found between the femur and the tibia.LEARNING OBJECTIVE Identify the purpose of the patella

KEY POINTS The primary functions of thepatellaare protection of thekneejoint and legextension. The lower part of theposteriorsurface hasvascularcanaliculi filled and is filled by fatty tissue, which is the infrapatellar fat pad. The patella is the largest sesamoid bone in the body. A sesamoid bone is a bone that is embedded within atendon.

TERMS patellaThe sesamoid bone of the knee; the kneecap. exostosesAn exostosis (plural:exostoses) is a benign bony growth, often covered withcartilage, on the surface of a bone or tooth.Give us feedback on this content:FULL TEXTThe patella, also known as the knee cap, is a triangular-shaped bone found between the femur and thetibia. The patella is the largest sesamoid bone in the body. A sesamoid bone is embedded within a tendon.

PatellaHuman left patellaThe patella is roughly triangular in shape with itsbasefacing proximally (towards the torso) and its tip (apex patellae) facing distally (towards the feet). Its anterior and posterior surfaces are joined laterally (left/right) by a thinner margin and medially (towards center) by a thicker margin.The anterior surface can be divided into three parts: The upper third is coarse, flattened, and rough; it serves for the attachment of the tendon of thequadricepsand often has exostoses. The middle third has numerous vascular canaliculi. The lower third includes thedistalapex, which serves as theoriginof the patellar ligament.The posterior surface is divided into two parts.The upper three-quarters articulates with the femur and is subdivided into a medial and alateralfacet by a vertical ledge which varies in shape.Four main types of articular surface can be distinguished. Most commonly, the medial articular surface is smaller than the lateral. Sometimes both articular surfaces are virtually equal in size. Occasionally, the medial surface is hypoplastic or the central ledge is only indicated. In an adult, the articular surface is about 12 cm2(1.9 sq in) and covered by cartilage, which can reach a maximal thickness of six mm (0.24 in) in the center at about 30 years of age. The lower part of the posterior surface has vascular canaliculi and is filled by fatty tissue, which is the infrapatellar fat pad.The patella protects the knee joint, but its primary functional role is knee extension . The patella increases the leverage that the tendon can exert on the femur by increasing the angle at which it acts.

Knee JointThis image shows the position of the patella relative to the articulation of the femur and the tibia.

Tibia and Fibula (Leg)READPROPOSE A CHANGEEDITDISCUSSIONHISTORYSHARE THIS CONTENTAssign Concept ReadingView QuizViewPowerPointTemplateThe tibia and the smaller fibula bones comprise the lower leg and articulate at the knee and ankle.LEARNING OBJECTIVE Contrast the fibula with the tibia

KEY POINTS Thetibia, also known as the shinbone, is a long bone of the lower leg, found between thepatellaand the ankle. Thefibulais a long, thin bone running parallel to the tibia. Like the femur, the tibia bears much of the body's weight and plays an essential role in movement and locomotion. The fibula, along with the tibia and the tarsals, forms the ankle.

TERMS fibulaThe smaller of the two bones in the lower leg, the calf bone. tibiaThe inner and usually the larger of the two bones of the leg or hind limb below theknee.Give us feedback on this content:FULL TEXTTibia and Fibula (Leg)The TibiaThe tibia, also known as the shin bone, is a long bone of the lower leg found between the patella and the ankle. It is the larger and stronger of the two bones in the leg below the knee in vertebrates (the other being the fibula), and connects the knee with the ankle bones. The tibia is named for the Greek aulos flute. It is commonly recognized as the strongest weight-bearing bone of the body. It forms the medial part of the ankle joint and is the second largest bone next to the femur. Like the femur, the tibia bears much of the body's weight and plays an essential role in movement and locomotion. In the male, its direction is vertical and parallel with the bone of the opposite side. In the female, it has a slightly oblique direction downward and laterally, to compensate for the greater obliqueness of the femur. The tibia is prismoid in form, which means it is polyhedron-like in shape with parallel planes containing an equal number of points. It is wider at the top, where it enters into the knee-joint, contracted in the lower third, and again enlarged but to a lesser extent towards the ankle joint.The tibia derives its arterialbloodsupply from two sources: the nutrientartery(main source) and the periosteal vessels derived from the anterior tibial artery.The superior tibiofibulararticulationis an arthrodial joint between thelateralcondyleof the tibia and the head of the fibula. The inferior tibiofibular articulation (tibiofibular syndesmosis) is formed by the rough, convex surface of the medial side of the lower end of the fibula, and a rough concave surface on the lateral side of the tibia. The tibia is connected to the fibula by aninterosseous membrane, forming a type of joint called a syndesmosis. The forward flat part of the tibia is called the fibia, often confused with the fibula.The FibulaThe fibula, also known as the calf bone, is a long, thin bone running parallel to the tibia. Its upper extremity is small, placed toward the back of the head of the tibia, below the level of the knee-joint, and excluded from the formation of this joint. Its lower extremity inclines a little forward so that it is on a plane anterior to that of the upper end. It projects below the tibia forming the lateral part of the ankle joint.The fibula has the following components: Body of fibula Lateral malleolus; Interosseous membrane connecting the fibula to the tibia, forming asyndesmosesjoint; The superior tibiofibular articulation is an arthrodial joint between the lateral condyle of the tibia and the head of the fibula; The inferior tibiofibular articulation (tibiofibular syndesmosis) is formed by the rough, convex surface of the medial side of the lower end of the fibula, and a rough concave surface on the lateral side of the tibia.The blood supply to the fibula is important for planning free tissue transfer because the fibula is commonly used to reconstruct themandible. The shaft is supplied in its middle third by a large nutrient vessel from the fibular artery. It is also perfused from its periosteum which receives many small branches from the fibular artery. The proximal head and the epiphysis are supplied by a branch of the anterior tibial artery. In harvesting the bone, the middle third is always taken and the ends preserved (4 cm proximally and 6 cm distally).In addition, in the tibia, ossification, which is the formation of the bone, starts from three centers; one in the shaft and one in each extremity, while the fibula is ossified from three centers, one for the shaft and another for either end. For the fibula, ossification begins in the body about the eighth week of fetallife, and extends toward the extremities. At birth the ends are cartilaginous. Ossification commences in the lower end in the second year, and in the upper end around 4 years old. The lower epiphysis, the first to ossify, unites with the body around 20 years old and the upper epiphysis joins around 25 years old.

The LegTibia and fibula in anatomical position with parts labeled.Give us feedback on this content:

Tarsals, Metatarsals, and Phalanges (Foot)READPROPOSE A CHANGEEDITDISCUSSIONHISTORYSHARE THIS CONTENTAssign Concept ReadingView QuizViewPowerPointTemplateThe human ankle and foot bones include tarsals (ankle), metatarsals (middle bones), and phalanges (toes).LEARNING OBJECTIVE Distinguish the subdivisions of the foot

KEY POINTS The human foot and ankle are strong and complex mechanical structures containing more than 26 bones (tarsals/ankle,metatarsals/mid-bones, andphalanges/toes), 33 joints, and more than a hundred muscles,tendons, and ligaments. The foot can be subdivided into the hindfoot, the midfoot, and the forefoot. The hindfoot is composed of the talus or ankle bone and the calcaneus or heel bone. The five irregular bones of the midfoot (the cuboid, navicular, and three cuneiform bones) form the arches of the foot. The forefoot is composed of five toes and the corresponding five proximal long bones forming themetatarsus. The human foot has two longitudinal arches and a transverse arch maintained by the interlocking shapes of the foot bones, strong ligaments, and pulling muscles during activity.

TERMS metatarsusThe part of the foot between the toes and the ankle, especially its five bones. tarsusThe part of the foot between thetibiaandfibulaand the metatarsus. phalangeOne of the bones of the finger or toe, also called phalanx.Give us feedback on this content:FULL TEXTThe human foot and ankle are strong and complex mechanical structures containing more than 26 bones (tarsals/ankle, metatarsals/mid-bones, and phalanges/toes ), 33 joints (20 of which are actively articulated), and more than a hundred muscles, tendons, and ligaments.

Main parts of footFoot (anatomic): 1 - ankle, 2 - heel bone, 3 - instep, 4 - metatarsus, 5 - toe.The foot can be subdivided into the hindfoot, the midfoot, and the forefoot.The hindfoot is composed of the talus or ankle bone and the calcaneus or heel bone. The two long bones of the lower leg, the tibia and fibula, are connected to the top of the talus to form the ankle. Connected to the talus at the subtalar joint, the calcaneus (the largest bone of the foot) is cushioned inferiorly by a layer of fat.The five irregular bones of the midfoot (the cuboid, navicular, and three cuneiform bones) form the arches of the foot which serve asshockabsorbers. The midfoot is connected to the hind- and fore-foot by muscles and theplantarfascia.The forefoot is composed of five toes and the corresponding five proximal long bones forming the metatarsus . Similar to the fingers of the hand, the bones of the toes are called phalanges. The big toe has two phalanges, while the other four toes have three phalanges. The joints between the phalanges are called interphalangeal; those between the metatarsus and phalanges are called metatarsophalangeal (MTP).

Arches of the FootSkeleton of foot. Lateral aspect.Both the midfoot and forefoot constitute the dorsum (the area facing upwards while standing) and the planum (the area facing downwards while standing).The human foot has two longitudinal arches and a transverse arch maintained by the interlocking shapes of the foot bones, strong ligaments, and pulling muscles during activity. The slight mobility of these arches when weight is applied to and removed from the foot makes walking and running more economical in terms of energy. As can be examined in a footprint, the medial longitudinal arch curves above the ground. This arch stretches from the heel bone over the "keystone" ankle bone to the three medial metatarsals. In contrast, thelaterallongitudinal arch is very low. With the cuboid serving as its keystone, it redistributes part of the weight to the calcaneus and thedistalend of the fifth metatarsal. The two longitudinal arches serve as pillars for the transverse arch which run obliquely across the tarsometatarsal joints. Excessive strain on the tendons and ligaments of the feet can result in fallen arches or flat feet.

MetatarsalThe metatarsus or metatarsal bones are a group of five long bones in the foot located between the tarsal bones of the hind- and mid-foot and the phalanges of the toes.