Tibia

The tibia /ˈtɪbiə/ (plural tibiae /ˈtɪbii/ or tibias), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outside of the tibia), and it connects the knee with the ankle bones. The tibia is found on the medial side of the leg next to the fibula and closer to the median plane or centre-line. The tibia is connected to the fibula by the interosseous membrane of the leg, forming a type of fibrous joint called a syndesmosis with very little movement. The tibia is named for the flute tibia. It is the second largest bone in the human body next to the femur. The leg bones are the strongest long bones as they support the rest of the body.

Tibia
Tibia - frontal view
Position of tibia (shown in red)
Braus 1921 293
Cross section of the leg showing the different compartments (latin terminology)
Details
ArticulationsKnee, ankle, superior and
inferior tibiofibular joint
Identifiers
Latin(os) tibia
MeSHD013977
TAA02.5.06.001
FMA24476
Anatomical terms of bone

Structure

In human anatomy, the tibia is the second largest bone next to the femur. As in other vertebrates the tibia is one of two bones in the lower leg, the other being the fibula, and is a component of the knee and ankle joints. The leg bones (femur, tibia and fibula) are the strongest long bones as they have to support the rest of the body.

The ossification or formation of the bone starts from three centers; one in the shaft and one in each extremity.

The tibia is categorized as a long bone and is as such composed of a diaphysis and two epiphyses. The diaphysis is the midsection of the tibia, also known as the shaft or body. While the epiphyses are the two rounded extremities of the bone; an upper (also known as superior or proximal) closest to the thigh and a lower (also known as inferior or distal) closest to the foot. The tibia is most contracted in the lower third and the distal extremity is smaller than the proximal.

Upper extremity

Gray257
Upper surface of right tibia. (Anterior is at top.)
Knee diagram
Knee

The proximal or upper extremity of the tibia is expanded in the transverse plane with a medial and lateral condyle, which are both flattened in the horizontal plane. The medial condyle is the larger of the two and is better supported over the shaft. The upper surfaces of the condyles articulate with the femur to form the tibiofemoral joint, the weightbearing part of the kneejoint.[1]

The medial and lateral condyle are separated by the intercondylar area, where the cruciate ligaments and the menisci attach. Here the medial and lateral intercondylar tubercle forms the intercondylar eminence. Together with the medial and lateral condyle the intercondylar region forms the tibial plateau, which both articulates with and is anchored to the lower extremity of the femur. The intercondylar eminence divides the intercondylar area into an anterior and posterior part. The anterolateral region of the anterior intercondylar area are perforated by numerous small openings for nutrient arteries.[1] The articular surfaces of both condyles are concave, particularly centrally. The flatter outer margins are in contact with the menisci. The medial condyles superior surface is oval in form and extends laterally onto the side of medial intercondylar tubercle. The lateral condyles superior surface is more circular in form and its medial edge extends onto the side of the lateral intercondylar tubercle. The posterior surface of the medial condyle bears a horizontal groove for part of the attachment of the semimembranosus muscle, whereas the lateral condyle has a circular facet for articulation with the head of the fibula.[1] Beneath the condyles is the tibial tuberosity which serves for attachment of the patellar ligament, a continuation of the quadriceps femoris muscle.[1]

Facets

The superior articular surface presents two smooth articular facets.

  • The medial facet, oval in shape, is slightly concave from side to side, and from before backward.
  • The lateral, nearly circular, is concave from side to side, but slightly convex from before backward, especially at its posterior part, where it is prolonged on to the posterior surface for a short distance.

The central portions of these facets articulate with the condyles of the femur, while their peripheral portions support the menisci of the knee joint, which here intervene between the two bones.

Intercondyloid eminence

Between the articular facets in the intercondylar area, but nearer the posterior than the anterior aspect of the bone, is the intercondyloid eminence (spine of tibia), surmounted on either side by a prominent tubercle, on to the sides of which the articular facets are prolonged; in front of and behind the intercondyloid eminence are rough depressions for the attachment of the anterior and posterior cruciate ligaments and the menisci.

Surfaces

The anterior surfaces of the condyles are continuous with one another, forming a large somewhat flattened area; this area is triangular, broad above, and perforated by large vascular foramina; narrow below where it ends in a large oblong elevation, the tuberosity of the tibia, which gives attachment to the patellar ligament; a bursa intervenes between the deep surface of the ligament and the part of the bone immediately above the tuberosity.

Posteriorly, the condyles are separated from each other by a shallow depression, the posterior intercondyloid fossa, which gives attachment to part of the posterior cruciate ligament of the knee-joint. The medial condyle presents posteriorly a deep transverse groove, for the insertion of the tendon of the semimembranosus.

Its medial surface is convex, rough, and prominent; it gives attachment to the medial collateral ligament.

The lateral condyle presents posteriorly a flat articular facet, nearly circular in form, directed downward, backward, and lateralward, for articulation with the head of the fibula. Its lateral surface is convex, rough, and prominent in front: on it is an eminence, situated on a level with the upper border of the tuberosity and at the junction of its anterior and lateral surfaces, for the attachment of the iliotibial band. Just below this a part of the extensor digitorum longus takes origin and a slip from the tendon of the biceps femoris is inserted.

Shaft

Gray258
Bones of the right leg. Anterior surface

The shaft or body of the tibia is triangular in cross-section and forms three borders: An anterior, medial and lateral or interosseous border. These three borders form three surfaces; the medial, lateral and posterior.[2] The forward flat part of the tibia is called the fibia, often confused with the fibula.[3]

Borders

The anterior crest or border, the most prominent of the three, commences above at the tuberosity, and ends below at the anterior margin of the medial malleolus. It is sinuous and prominent in the upper two-thirds of its extent, but smooth and rounded below; it gives attachment to the deep fascia of the leg.

The medial border is smooth and rounded above and below, but more prominent in the center; it begins at the back part of the medial condyle, and ends at the posterior border of the medial malleolus; its upper part gives attachment to the tibial collateral ligament of the knee-joint to the extent of about 5 cm., and insertion to some fibers of the popliteus muscle; from its middle third some fibers of the soleus and flexor digitorum longus muscles take origin.

The interosseous crest or lateral border is thin and prominent, especially its central part, and gives attachment to the interosseous membrane; it commences above in front of the fibular articular facet, and bifurcates below, to form the boundaries of a triangular rough surface, for the attachment of the interosseous ligament connecting the tibia and fibula.

Surfaces

The medial surface is smooth, convex, and broader above than below; its upper third, directed forward and medialward, is covered by the aponeurosis derived from the tendon of the sartorius, and by the tendons of the Gracilis and Semitendinosus, all of which are inserted nearly as far forward as the anterior crest; in the rest of its extent it is subcutaneous.

The lateral surface is narrower than the medial; its upper two-thirds present a shallow groove for the origin of the Tibialis anterior; its lower third is smooth, convex, curves gradually forward to the anterior aspect of the bone, and is covered by the tendons of the Tibialis anterior, Extensor hallucis longus, and Extensor digitorum longus, arranged in this order from the medial side.

The posterior surface presents, at its upper part, a prominent ridge, the popliteal line, which extends obliquely downward from the back part of the articular facet for the fibula to the medial border, at the junction of its upper and middle thirds; it marks the lower limit of the insertion of the Popliteus, serves for the attachment of the fascia covering this muscle, and gives origin to part of the Soleus, Flexor digitorum longus, and Tibialis posterior. The triangular area, above this line, gives insertion to the Popliteus. The middle third of the posterior surface is divided by a vertical ridge into two parts; the ridge begins at the popliteal line and is well-marked above, but indistinct below; the medial and broader portion gives origin to the Flexor digitorum longus, the lateral and narrower to part of the Tibialis posterior. The remaining part of the posterior surface is smooth and covered by the Tibialis posterior, Flexor digitorum longus, and Flexor hallucis longus. Immediately below the popliteal line is the nutrient foramen, which is large and directed obliquely downward.

Lower extremity

Tibia - inferior epiphysis (anterior view)
Lower extremity of tibia seen from the front
Tibia - inferior epiphysis (posterior view)
Lower extremity of tibia seen from the back

The distal end of the tibia is much smaller than the proximal end and presents five surfaces; it is prolonged downward on its medial side as a strong pyramidal process, the medial malleolus. The lower extremity of the tibia together with the fibula and talus forms the ankle joint.

Surfaces

The inferior articular surface is quadrilateral, and smooth for articulation with the talus. It is concave from before backward, broader in front than behind, and traversed from before backward by a slight elevation, separating two depressions. It is continuous with that on the medial malleolus.

The anterior surface of the lower extremity is smooth and rounded above, and covered by the tendons of the Extensor muscles; its lower margin presents a rough transverse depression for the attachment of the articular capsule of the ankle-joint.

The posterior surface is traversed by a shallow groove directed obliquely downward and medialward, continuous with a similar groove on the posterior surface of the talus and serving for the passage of the tendon of the Flexor hallucis longus.

The lateral surface presents a triangular rough depression for the attachment of the inferior interosseous ligament connecting it with the fibula; the lower part of this depression is smooth, covered with cartilage in the fresh state, and articulates with the fibula. The surface is bounded by two prominent borders (the anterior and posterior colliculi), continuous above with the interosseous crest; they afford attachment to the anterior and posterior ligaments of the lateral malleolus.

The medial surface -- see medial malleolus for details.

Fractures

Ankle fractures of the tibia have several classification systems based on location or mechanism:

Blood supply

The tibia is supplied with blood from two sources: A nutrient artery, as the main source, and periosteal vessels derived from the anterior tibial artery.[4]

Joints

The tibia is a part of four joints; the knee, ankle, superior and inferior tibiofibular joint.

In the knee the tibia forms one of the two articulations with the femur, often referred to as the tibiofemoral components of the knee joint.[5][6] This is the weightbearing part of the knee joint.[2] The tibiofibular joints are the articulations between the tibia and fibula which allows very little movement. The proximal tibiofibular joint is a small plane joint. The joint is formed between the undersurface of the lateral tibial condyle and the head of fibula. The joint capsule is reinforced by anterior and posterior ligament of the head of the fibula.[2] The distal tibiofibular joint (tibiofibular syndesmosis) is formed by the rough, convex surface of the medial side of the distal end of the fibula, and a rough concave surface on the lateral side of the tibia.[2] The part of the ankle joint known as the talocrural joint, is a synovial hinge joint that connects the distal ends of the tibia and fibula in the lower limb with the proximal end of the talus. The articulation between the tibia and the talus bears more weight than between the smaller fibula and the talus.

Development

Gray260
Plan of ossification of the tibia. From three centers.
Gray261
Epiphysial lines of tibia and fibula in a young adult. Anterior aspect.

The tibia is ossified from three centers; a primary center for the diaphysis (shaft) and a secondary center for each epiphysis (extremity). Ossification begins in the center of the body, about the seventh week of fetal life, and gradually extends toward the extremities.

The center for the upper epiphysis appears before or shortly after birth at close to 34 weeks gestation; it is flattened in form, and has a thin tongue-shaped process in front, which forms the tuberosity; that for the lower epiphysis appears in the second year.

The lower epiphysis fuses with the tibial shaft at about the eighteenth, and the upper one fuses about the twentieth year.

Two additional centers occasionally exist, one for the tongue-shaped process of the upper epiphysis, which forms the tuberosity, and one for the medial malleolus.

Function

Muscle attachments

Muscle Direction Attachment[7]
Tensor fasciae latae muscle Insertion Gerdy's tubercle
Quadriceps femoris muscle Insertion Tuberosity of the tibia
Sartorius muscle Insertion Pes anserinus
Gracilis muscle Insertion Pes anserinus
Semitendinosus muscle Insertion Pes anserinus
Horizontal head of the semimembranosus muscle Insertion Medial condyle
Popliteus muscle Insertion Posterior side of the tibia over the soleal line
Tibialis anterior muscle Origin Lateral side of the tibia
Extensor digitorum longus muscle Origin Lateral condyle
Soleus muscle Origin Posterior side of the tibia under the soleal line
Flexor digitorum longus muscle Origin Posterior side of the tibia under the soleal line

Strength

The tibia has been modeled as taking an axial force during walking that is up to 4.7 bodyweight. Its bending moment in the sagittal plane in the late stance phase is up to 71.6 bodyweight times millimetre.[8]

Clinical significance

Fracture

Fractures of the tibia can be divided into those that only involve the tibia; bumper fracture, Segond fracture, Gosselin fracture, toddler's fracture, and those including both the tibia and fibula; trimalleolar fracture, bimalleolar fracture, Pott's fracture.

Society and culture

In Judaism, the tibia, or shankbone, of a goat is used in the Passover Seder plate.

Other animals

The structure of the tibia in most other tetrapods is essentially similar to that in humans. The tuberosity of the tibia, a crest to which the patellar ligament attaches in mammals, is instead the point for the tendon of the quadriceps muscle in reptiles, birds, and amphibians, which have no patella.[9]

Additional images

Right tibia - close up - animation

Shape of right tibia

Human tibia.stl

3D image

Braus 1921 292

Longitudinal section of tibia showing interior

Gray345

Right knee-joint. Anterior view.

Gray347

Right knee joint from the front, showing interior ligaments

Gray348

Left knee joint from behind, showing interior ligaments

Gray356

Left talocrural joint

Gray357

Coronal section through right talocrural and talocalcaneal joints

Slide3Bubu

Dorsum of Foot. Ankle joint. Deep dissection

Slide2bubu

Dorsum of Foot. Ankle joint. Deep dissection

Slide2tat

Ankle joint. Deep dissection. Anterior view

Bones of the right leg. Anterior surface

Bones of the right leg. Posterior surface

Slide2coco

Dorsum of Foot. Ankle joint. Deep dissection.

Slide4CEC3

Ankle joint. Deep dissection.

Slide5CEC4

Ankle joint. Deep dissection.

Slide7CEC6

Ankle joint. Deep dissection.

Slide8CEC7

Ankle joint. Deep dissection.

See also

References

This article incorporates text in the public domain from page 256 of the 20th edition of Gray's Anatomy (1918)

  1. ^ a b c d Drake, Richard L.; Vogl, A. Wayne; Mitchell, Adam W. M. (2010). Gray´s Anatomy for Students (2nd ed.). pp. 558–560. ISBN 978-0-443-06952-9.
  2. ^ a b c d Drake, Richard L.; Vogl, A. Wayne; Mitchell, Adam W. M. (2010). Gray´s Anatomy for Students (2nd ed.). pp. 584–588. ISBN 978-0-443-06952-9.
  3. ^ "Chapter 12: THE BONES OF THE LOWER LIMB". www.dartmouth.edu. Retrieved 2018-06-17.
  4. ^ Nelson G, Kelly P, Peterson L, Janes J (1960). "Blood supply of the human tibia". J Bone Joint Surg Am. 42-A: 625–36. PMID 13854090.
  5. ^ Rytter S, Egund N, Jensen LK, Bonde JP (2009). "Occupational kneeling and radiographic tibiofemoral and patellofemoral osteoarthritis". J Occup Med Toxicol. 4 (1): 19. doi:10.1186/1745-6673-4-19. PMC 2726153. PMID 19594940.
  6. ^ Gill TJ, Van de Velde SK, Wing DW, Oh LS, Hosseini A, Li G (December 2009). "Tibiofemoral and patellofemoral kinematics after reconstruction of an isolated posterior cruciate ligament injury: in vivo analysis during lunge". Am J Sports Med. 37 (12): 2377–85. doi:10.1177/0363546509341829. PMC 3832057. PMID 19726621.
  7. ^ Bojsen-Møller, Finn; Simonsen, Erik B.; Tranum-Jensen, Jørgen (2001). Bevægeapparatets anatomi [Anatomy of the Locomotive Apparatus] (in Danish) (12th ed.). pp. 364–367. ISBN 978-87-628-0307-7.
  8. ^ Wehner, T; Claes, L; Simon, U (2009). "Internal loads in the human tibia during gait". Clin Biomech. 24 (3): 299–302. doi:10.1016/j.clinbiomech.2008.12.007. PMID 19185959.
  9. ^ Romer, Alfred Sherwood; Parsons, Thomas S. (1977). The Vertebrate Body. Philadelphia, PA: Holt-Saunders International. p. 205. ISBN 0-03-910284-X.
Agua Tibia Wilderness

Agua Tibia Wilderness (ATW) is a 17,961-acre (72.69 km2) protected area in Riverside and San Diego counties, in the U.S. state of California. It is mostly within the Palomar Ranger District of the Cleveland National Forest. The area was originally protected as the Agua Tibia Primitive Area until January 1975 when it was added to the National Wilderness Preservation System with the passage of Public Law 93-632 by the United States Congress. Between its inception and 1984, the ATW was San Diego County's only officially designated wilderness area. The Spanish name, Agua Tibia, translates as warm water.

Its approximate boundaries are:

North – SR-79 South

East – Arroyo Seco River

South – Fray Creek

West – Pala Road

Ankle

The ankle, or the talocrural region, is the region where the foot and the leg meet. The ankle includes three joints: the ankle joint proper or talocrural joint, the subtalar joint, and the inferior tibiofibular joint. The movements produced at this joint are dorsiflexion and plantarflexion of the foot. In common usage, the term ankle refers exclusively to the ankle region. In medical terminology, "ankle" (without qualifiers) can refer broadly to the region or specifically to the talocrural joint.The main bones of the ankle region are the talus (in the foot), and the tibia and fibula (in the leg). The talocrural joint is a synovial hinge joint that connects the distal ends of the tibia and fibula in the lower limb with the proximal end of the talus. The articulation between the tibia and the talus bears more weight than that between the smaller fibula and the talus.

Arthropod leg

The arthropod leg is a form of jointed appendage of arthropods, usually used for walking. Many of the terms used for arthropod leg segments (called podomeres) are of Latin origin, and may be confused with terms for bones: coxa (meaning hip, plural coxae), trochanter (compare trochanter), femur (plural femora), tibia (plural tibiae), tarsus (plural tarsi), ischium (plural ischia), metatarsus, carpus, dactylus (meaning finger), patella (plural patellae).

Homologies of leg segments between groups are difficult to prove and are the source of much argument. Some authors posit up to eleven segments per leg for the most recent common ancestor of extant arthropods but modern arthropods have eight or fewer. It has been argued that the ancestral leg need not have been so complex, and that other events, such as successive loss of function of a Hox-gene, could result in parallel gains of leg segments.

Aulos

An aulos (Ancient Greek: αὐλός, plural αὐλοί, auloi) or tibia (Latin) was an ancient Greek wind instrument, depicted often in art and also attested by archaeology.

An aulete (αὐλητής, aulētēs) was the musician who performed on an aulos. The ancient Roman equivalent was the tibicen (plural tibicines), from the Latin tibia, "pipe, aulos." The neologism aulode is sometimes used by analogy with rhapsode and citharode (citharede) to refer to an aulos player, who may also be called an aulist; however, aulode more commonly refers to a singer who sang the accompaniment to a piece played on the aulos.

Dolichosuchus

Dolichosuchus (meaning "long crocodile") is the name given to a genus of dinosaur from the Triassic. It was originally classified in the disused family Hallopodidae, but has since been reclassified as a coelophysoid. A single fossil (consisting of a single lower leg bone, or tibia) was found in Germany. Since only one bone was discovered, the genus is considered a nomen dubium. Some scientists have noted that the tibia closely resembles those of Liliensternus and Dilophosaurus.The type species is D. cristatus, described by Huene in 1932. The bone was recovered from the Lower or Middle Stubensandstein formation.

Fibula

The fibula or calf bone is a leg bone located on the lateral side of the tibia, with which it is connected above and below. It is the smaller of the two bones and in proportion to its length, the slenderest of all the long bones. 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 as to be on a plane anterior to that of the upper end; it projects below the tibia, and forms the lateral part of the ankle-joint.

Genu varum

Genu varum (also called bow-leggedness, bandiness, bandy-leg, and tibia vara), is a varus deformity marked by (outward) bowing at the knee, which means that the lower leg is angled inward (medially) in relation to the thigh's axis, giving the limb overall the appearance of an archer's bow. Usually medial angulation of both lower limb bones (femur and tibia) is involved.

Human leg

The human leg, in the general meaning, is the entire lower limb of the human body, including the foot, thigh and even the hip or gluteal region. However, the definition in human anatomy refers only to the section of the lower limb extending from the knee to the ankle, also known as the crus.

Legs are used for standing, and all forms of locomotion including recreational such as dancing, and constitute a significant portion of a person's mass. Female legs generally have greater hip anteversion and tibiofemoral angles, but shorter femur and tibial lengths than those in males.

Knee

In humans and other primates, the knee joins the thigh with the leg and consists of two joints: one between the femur and tibia (tibiofemoral joint), and one between the femur and patella (patellofemoral joint). It is the largest joint in the human body. The knee is a modified hinge joint, which permits flexion and extension as well as slight internal and external rotation. The knee is vulnerable to injury and to the development of osteoarthritis.

It is often termed a compound joint having tibiofemoral and patellofemoral components. (The fibular collateral ligament is often considered with tibiofemoral components.)

Lateral condyle of tibia

The lateral condyle is the lateral portion of the upper extremity of tibia.It serves as the insertion for the biceps femoris muscle (small slip). Most of the tendon of the biceps femoris inserts on the fibula.

Malleolus

A malleolus is the bony prominence on each side of the human ankle.

Each leg is supported by two bones, the tibia on the inner side (medial) of the leg and the fibula on the outer side (lateral) of the leg. The medial malleolus is the prominence on the inner side of the ankle, formed by the lower end of the tibia. The lateral malleolus is the prominence on the outer side of ankle, formed by the lower end of the fibula.

The word malleolus (), plural malleoli (), comes from Latin and means "small hammer". (It is cognate with mallet.)

Medial condyle of tibia

The medial condyle is the medial portion of the upper extremity of tibia.

It is the site of insertion for the semimembranosus muscle.

Popliteus muscle

The popliteus muscle in the leg is used for unlocking the knees when walking, by laterally rotating the femur on the tibia during the closed chain portion of the gait cycle (one with the foot in contact with the ground). In open chain movements (when the involved limb is not in contact with the ground), the popliteus muscle medially rotates the tibia on the femur. It is also used when sitting down and standing up. It is the only muscle in the posterior (back) compartment of the lower leg that acts just on the knee and not on the ankle. The gastrocnemius muscle acts on both joints.

Posterior cruciate ligament

The posterior cruciate ligament (or PCL) is one of the four major ligaments of the knee. It connects the posterior intercondylar area of the tibia to the medial condyle of the femur. This configuration allows the PCL to resist forces pushing the tibia posteriorly relative to the femur.

The PCL is an intracapsular ligament along with the anterior cruciate ligament (ACL) because it lies deep within the knee joint. They are both isolated from the fluid-filled synovial cavity, with the synovial membrane wrapped around them. The PCL gets its name by attaching to the posterior portion of the tibia.

Shin splints

Shin splints, also known as medial tibial stress syndrome (MTSS), is defined by the American Academy of Orthopaedic Surgeons as "pain along the inner edge of the shinbone.

(tibia)." Shin splints are usually caused by repeated trauma to the connective muscle tissue surrounding the tibia. They are a common injury affecting athletes who engage in running sports or other forms of physical activity, including running and jumping. They are characterized by general pain in the lower region of the leg between the knee and the ankle. Shin splints injuries are specifically located in the middle to lower thirds of the anterior or lateral part of the tibia, which is the larger of two bones comprising the lower leg.

Shin splints are the most prevalent lower leg injury and affect a broad range of individuals. It affects mostly runners and accounts for approximately 13% to 17% of all running-related injuries. High school age runners see shin splints injury rates of approximately 13%. Aerobic dancers have also been known to have shin splints, with injury rates as high as 22%. Military personnel undergoing basic training experience shin splints injury rates between 4–8%.

Tarsus (skeleton)

The tarsus is a cluster of seven articulating bones in each foot situated between the lower end of tibia and fibula of the lower leg and the metatarsus. It is made up of the midfoot (cuboid, medial, intermediate, and lateral cuneiform, and navicular) and hindfoot (talus and calcaneus).

The tarsus articulates with the bones of the metatarsus, which in turn articulate with the proximal phalanges of the toes. The joint between the tibia and fibula above and the tarsus below is referred to as the ankle joint.

In humans the largest bone in the tarsus is the calcaneus, which is the weight-bearing bone within the heel of the foot.

Tibia (video game)

Tibia is a massively multiplayer online role-playing game (MMORPG) created by CipSoft. It is one of the oldest MMORPGs and was considered most noteworthy in its early years; however, with the development of MMORPGs, its popularity has grown much slower than other MMORPGs. It was first released in January 1997.

It is a free game which is open to the public, though players have the option to pay a fee in order to upgrade to a premium account, granting special in-game benefits, including additional areas to explore, access to vocation promotions, and extra spells.

Tibialis anterior muscle

The tibialis anterior is a muscle in humans that originates in the upper two-thirds of the lateral (outside) surface of the tibia and inserts into the medial cuneiform and first metatarsal bones of the foot. It acts to dorsiflex and invert the foot. This muscle is mostly located near the shin.

It is situated on the lateral side of the tibia; it is thick and fleshy above, tendinous below. The tibialis anterior overlaps the anterior tibial vessels and deep peroneal nerve in the upper part of the leg.

Tuberosity of the tibia

The tuberosity of the tibia or tibial tuberosity or tibial tubercle is a large oblong elevation on the proximal, anterior aspect of the tibia, just below where the anterior surfaces of the lateral and medial tibial condyles end.

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