Malleolus

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Malleolus
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Coronal cross-section through the right ankle showing the lateral malleolus (right) and medial malleolus (left)
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The left leg, with the medial malleolus labeled at bottom right.
Details
Identifiers
Latin malleolus, malleoli
TA98 A02.5.06.020
A02.5.07.014
TA2 1421, 1442
Anatomical terms of bone

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

Contents

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 the ankle, formed by the lower end of the fibula.

The word malleolus ( /məˈlələs,mæ-/ [1] [2] ), plural malleoli ( /məˈləˌl,mæ-/ ), comes from Latin and means "small hammer". (It is cognate with mallet .)

Medial malleolus

The medial malleolus is found at the foot end of the tibia. The medial surface of the lower extremity of tibia is prolonged downward to form a strong pyramidal process, flattened from without inward - the medial malleolus.

The major structure that passes anterior to the medial malleolus is the saphenous vein.

Structures that pass behind medial malleolus deep to the flexor retinaculum:

Lateral malleolus

The lateral malleolus is found at the foot end of the fibula, of a pyramidal form, and somewhat flattened from side to side; it descends to a lower level than the medial malleolus.

A major structure that is located between the lateral malleolus and the Achilles tendon is the sural nerve.

Clinical significance

Fracture

A bimalleolar fracture is a fracture of the ankle that involves the lateral malleolus and the medial malleolus. Studies have shown [3] that bimalleolar fractures are more common in women, people over 60 years of age, and patients with existing comorbidities. [3]

A trimalleolar fracture is a fracture of the ankle that involves the lateral malleolus, the medial malleolus, and the distal posterior aspect of the tibia, which can be termed the posterior malleolus. The trauma is sometimes accompanied by ligament damage and dislocation. [4]

Additional images

Related Research Articles

Foot Anatomical structure found in vertebrates

The foot is an anatomical structure found in many vertebrates. It is the terminal portion of a limb which bears weight and allows locomotion. In many animals with feet, the foot is a separate organ at the terminal part of the leg made up of one or more segments or bones, generally including claws or nails.

<span class="mw-page-title-main">Human leg</span> Lower extremity or limb of the human body (foot, lower leg, thigh and hip)

The human leg, in the general word sense, is the entire lower limb of the human body, including the foot, thigh or sometimes 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 or, especially in non-technical use, the shank. 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.

<span class="mw-page-title-main">Ulna</span> Medial bone from forearm

The ulna is a long bone found in the forearm that stretches from the elbow to the smallest finger, and when in anatomical position, is found on the medial side of the forearm. That is, the ulna is on the same side of the forearm as the little finger. It runs parallel to the radius, the other long bone in the forearm. The ulna is usually slightly longer than the radius, but the radius is thicker. Therefore, the radius is considered to be the larger of the two.

Fibularis longus Superficial muscle in the lateral compartment of the leg

In human anatomy, the fibularis longus is a superficial muscle in the lateral compartment of the leg. It acts to tilt the sole of the foot away from the midline of the body (eversion) and to extend the foot downward away from the body at the ankle.

Tibia Long bone of the lower leg

The tibia, 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, 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 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.

Fibula Leg bone on the lateral side of the tibia

The fibula or calf bone is a leg bone on the lateral side of the tibia, to which it is connected above and below. It is the smaller of the two bones and, in proportion to its length, the most slender of all the long bones. Its upper extremity is small, placed toward the back of the head of the tibia, below 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.

Ankle Region where the foot and the leg meet

The ankle, or the talocrural region, or the jumping bone (informal) is the area 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" can refer broadly to the region or specifically to the talocrural joint.

Radius (bone) One of the two long bones of the forearm

The radius or radial bone is one of the two large bones of the forearm, the other being the ulna. It extends from the lateral side of the elbow to the thumb side of the wrist and runs parallel to the ulna. The ulna is usually slightly longer than the radius, but the radius is thicker. Therefore the radius is considered to be the larger of the two. It is a long bone, prism-shaped and slightly curved longitudinally.

Pott's fracture, also known as Pott's syndrome I and Dupuytren fracture, is an archaic term loosely applied to a variety of bimalleolar ankle fractures. The injury is caused by a combined abduction external rotation from an eversion force. This action strains the sturdy medial (deltoid) ligament of the ankle, often tearing off the medial malleolus due to its strong attachment. The talus then moves laterally, shearing off the lateral malleolus or, more commonly, breaking the fibula superior to the tibiofibular syndesmosis. If the tibia is carried anteriorly, the posterior margin of the distal end of the tibia is also sheared off by the talus. A fractured fibula in addition to detaching the medial malleolus will tear the tibiofibular syndesmosis. The combined fracture of the medial malleolus, lateral malleolus, and the posterior margin of the distal end of the tibia is known as a "trimalleolar fracture".

Tibial nerve Branch of the sciatic nerve

The tibial nerve is a branch of the sciatic nerve. The tibial nerve passes through the popliteal fossa to pass below the arch of soleus.

Talus bone One of the foot bones that forms the tarsus

The talus, talus bone, astragalus, or ankle bone is one of the group of foot bones known as the tarsus. The tarsus forms the lower part of the ankle joint. It transmits the entire weight of the body from the lower legs to the foot.

Flexor digitorum longus muscle Muscle located on the tibial side of the leg

The flexor digitorum longus muscle is situated on the tibial side of the leg. At its origin it is thin and pointed, but it gradually increases in size as it descends. It serves to flex the second, third, fourth, and fifth toes.

Extensor digitorum longus muscle Pennate muscle, situated at the lateral part of the front of the leg

The extensor digitorum longus is a pennate muscle, situated at the lateral part of the front of the leg.

Fibularis brevis Shorter and smaller of the fibularis (peroneus) muscles

In human anatomy, the fibularis brevis is a muscle that lies underneath the fibularis longus within the lateral compartment of the leg. It acts to tilt the sole of the foot away from the midline of the body (eversion) and to extend the foot downward away from the body at the ankle.

Ankle fracture Medical condition

An ankle fracture is a break of one or more of the bones that make up the ankle joint. Symptoms may include pain, swelling, bruising, and an inability to walk on the injured leg. Complications may include an associated high ankle sprain, compartment syndrome, stiffness, malunion, and post-traumatic arthritis.

Inferior extensor retinaculum of foot Y-shaped band placed in front of the ankle-joint

The inferior extensor retinaculum of the foot is a Y-shaped band placed in front of the ankle-joint, the stem of the Y being attached laterally to the upper surface of the calcaneus, in front of the depression for the interosseous talocalcaneal ligament; it is directed medialward as a double layer, one lamina passing in front of, and the other behind, the tendons of the peroneus tertius and extensor digitorum longus.

Deltoid ligament

The deltoid ligament is a strong, flat, triangular band, attached, above, to the apex and anterior and posterior borders of the medial malleolus. The deltoid ligament is composed of 4 fibers: 1. Anterior tibiotalar ligament 2. Tibiocalcaneal ligament 3. Posterior tibiotalar ligament 4. Tibionavicular ligament. It consists of two sets of fibers, superficial and deep.

Interosseous membrane of leg

The interosseous membrane of the leg extends between the interosseous crests of the tibia and fibula, helps stabilize the Tib-Fib relationship and separates the muscles on the front from those on the back of the leg.

Deep fascia of leg Forms a complete investment to the muscles

The deep fascia of leg, or crural fascia forms a complete investment to the muscles, and is fused with the periosteum over the subcutaneous surfaces of the bones.

Crus fracture

A crus fracture is a fracture of the lower legs bones meaning either or both of the tibia and fibula.

References

PD-icon.svgThis article incorporates text in the public domain from page 5 of the 20th edition of Gray's Anatomy (1918)

  1. "Malleolus". Merriam-Webster Dictionary . Retrieved 2016-01-22.
  2. "Malleolus". Lexico UK English Dictionary. Oxford University Press. Archived from the original on 2020-03-22.
  3. 1 2 Tejwani, Nirmal; et al. (2007). "Are Outcomes of Bimalleolar Fractures Poorer Than Those of Lateral Malleolar Fractures with Medial Ligamentous Injury?". Journal of Bone and Joint Surgery. 89 (7): 1438–1441. doi:10.2106/JBJS.F.01006. PMID   17606780. Archived from the original on 15 February 2010. Retrieved 26 November 2010.
  4. Orthopaedic Trauma Association (September 2007). "Ankle Fractures". AAOS.