Glossary of Foot and Ankle Terms

We are very grateful to Patrick O'Connor, MD and Thomas Schaller, MD, the authors of Footworks II: The Patient's Guide to the Foot and Ankle for allowing us to use the extensive glossary of foot and ankle terms in his book.

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Accessory Navicular Syndrome: Also called Pre-Hallux Syndrome. An unusual "extra" bony extension of the navicular bone. An accessory navicular can cause pain at the fibrous interface between the extra bone and the navicular bone; a condition that commonly presents in adolescents with an accessory navicular. Alternatively, symptoms can occur due to the prominence of the bone on the inside of the foot. 

Achilles Tendon: Long, strong tendon in the back of the leg, which attaches the calf muscle (gastrocnemius and soleus) to the heel.

Adipose: Fat tissue.

Ankle Block: A form of local anesthesia which "blocks" all, or a combination of, the five main nerves leading to the foot.

Ankylosing Spondylitis: Arthritic inflammation of the spine, resulting in stiffness.

Anterior: Pertaining to or toward the front plane of the body.

Anterior Tibialis: Muscle that begins in the lower leg and moves the foot upwards.

Apophysitis: Inflammation of an apophysis (Greek word meaning a process or projection of a bone). When discussing the foot, the term is primarily confined to the irritation of the back of the heel bone in children. In fact, it may represent an inflammation of the Achilles tendon or bursa, rather than a bone. Also called Sever's Disease.

Arthrodesis: The procedure of solidly fusing a joint (Arthro=joint + desis = fusion).

Arthroplasty: The surgical refashioning or replacement of a joint to restore function and integrity.

Arthroeresis: An implant inserted between two bones of the hindfoot (talus and calcaneus) to correct flexible flatfoot in children. This implant, which is prone to breakage and dislocation, is unproven as a viable treatment.

Arthroscopy: A surgical procedure to directly view and operate within a joint through small puncture wounds.

Articular Cartilage: The smooth, white, firm connective tissue covering ends of bones, thus creating joints.

Athlete's Foot: Fungal infection often caused by Trichophyton rubrum, due in part to an athlete walking barefoot in a locker room. Treatment is to "dry out" the web spaces and to use an anti-fungal powder or cream. Also called Tinea Pedis.

Avascular Necrosis: Interruption of the blood supply to a particular bone. When this occurs at the end of a bone within a joint, the contour of that surface may change, causing a painful joint (arthrosis).

Avulsion Fracture: Abnormality resulting when bone is pulled away by an attached tendon.

Bimalleolar Fracture: Referring to a common type of ankle fracture, where both bones (the large bump or prominences that you can feel on both sides of your ankle) are broken.

Blount's Disease: An abnormality in the growth plate of the tibia, leading to marked bowing of the lower leg bones (tibia).

Bunion: Prominence on the inside edge of the great toe, usually associated with a hallux valgus deformity (big toe is angled away from the midline).

Bunionette: Small "bunion-like" deformity on the outside of the foot, near the base of the fifth toe.

Bursa: A sac containing a tiny amount of fluid, present where friction needs to be minimized, such as a tendon or skin gliding over a bony prominence. Best thought of as a deflated balloon containing several drops of oil. The most obvious bursa sac is beneath the loose skin behind the elbow.

Bursitis: Inflammation of a bursal sac.

Callus: Thickening of the outer layer of skin, due to irritation or pressure.

Cavus Foot: High arches.

Cellulitis: Inflammation of the skin, often associated with a localized infection of the skin.

Charcot Foot: A foot affected by a painless degenerative change of the bones, due to excessive repetitive localized force in a foot with a loss of sensation.

Charot-Marie-Tooth Disease: Usually characterized by weakness of the peroneal leg muscles, and commonly resulting in a high arched foot with marked claw toes.

Cheilectomy: Surgical removal of spurs created in a joint.

Clawtoe: Curling of the lesser toes whereby both small joints of a toe are flexed.

Compartment Syndrome: Increased pressure in one or more of the four or five compartments of the leg, resulting in pain and possible muscle damage. See "Fascia".

Contusion: A bruise in which the skin remains unbroken.

Corn: A hyperkeratosis (i.e. a thickening of the normal keratin of the skin). Corns are either hard (helomata dura) and usually located on top of the toes, or soft (helomata mollia) and located between the toes.

Crepitus: Grinding most often produced by joint surfaces not being smooth.

Degenerative: Having the tendency to deteriorate, or implying a wear and tear process.

Denis-Browne Bar: A metal bar connected to the bottom of a child's shoes to help correct in-or-out toeing.

Dermis: The deeper layer of the skin containing nerves, blood vessels, and sweat glands.

Dessicating Agent: Liquid solution which dries out an area.

Diabetes: A complex disease affecting multiple organ systems, due to insulin deficiency, and resulting in a high blood glucose level.

Digital Nerve: Nerve running to the toes.

Diplegic: One who has arms and legs affected by a physical trauma, but the legs are worse.

Distal: Farthest away from the trunk or center of the body. Opposite of the term "proximal".

Dorsiflexion: Bending the foot upward or toward the shin.

Dysplasia: From the Greek "dys" meaning "bad", and "plasis" meaning "a molding". It is a very general term used to mean any abnormal tissue development.

Eccymosis: "Black and blue" discoloration of the skin, resulting from a bruise or injury.

Edema: Swelling.

Epidermis: Outer layer of the skin.

Equinovalgus: Abnormality of the foot, causing it to point toward the floor and causing the heel to turn out.

Equinovarus: Abnormality causing the foot to point toward the floor

Equinus: Abnormality causing the foot and toes to point toward the floor.

Equinus contracture: A term used to describe a limitation in the upwards ankle motion, specifically the inability for the ankle to be brought past a neutral position (right angle to the shin bone).

EVA: Ethylene Vinyl Acetate. A cushioning material used for insoles in shoe manufacture.

Exostosis: A bony prominance, see "Bunion".

Extrinsic Muscles: Originate outside of, or cross into, areas above the foot (i.e. the muscles of the lower leg that cross the ankle joint and help move the foot and toes). Compare with intrinsic muscles, which are entirely contained within the foot.

Fascia: Tough fibrous tissue enveloping muscles and separating them into various compartments.

Fibula: The smaller and more lateral of the two long bones of the lower leg.

Femur: Better known as the thigh bone, comprising the hip at one end and the knee at the other.

Fracture (broken bone): Indicates a break, most commonly applied to a bone, indicating that the structure of the bone is disrupted. Fractures can be simple or complex (many pieces); closed or open (breaking through the skin); and stable or unstable.

Freiberg's Infraction: Is an osteonecrosis, usually involving the 2nd metatarsal head in adolescents, thought to be due to repetitive trauma to a developing bone possibly leading to a loss of localized blood supply. Swelling and discomfort occur, and treatment may require surgical debridement.

Gait: Manner of walking. Can be normal or abnormal, such as antalgic (painful) gait where the stance phase is shortened.

Ganglion: A non-cancerous cyst filled with a clear gelatinous-like material.

Gangrene: Tissue death caused by arterial blockage, occasionally caused by infection.

Gastrocnemius: One of the two major muscles of the calf (the other being the soleus), which merge to form the Achilles tendon.

Genu varum: Bow legs.

Genu valgum: Knock knees.

Gout: Arthritic condition caused by excessive uric acid in the bloodstream. Gout can produce acutely painful joints if the uric acid crystallizes in the lining of a joint. It can also lead to long-term stiffness and, occasionally, soft mineral deposits beneath the skin.

Great Toe: The largest toe of the foot. Also called the hallux.

Hagland's Deformity: Bony prominence of the heel, near where the Achilles tendon attaches to the heel bone.

Hallux: The great or largest toe.

Hallux Valgus: A lateral deviation of the great toe, based at the metatarsal phalangeal joint.

Hallux Rigidus: Stiffness and rigidity of the great toe associated with osteoarthritis (loss of cartilage).

Hammertoe: Curling of the lesser toes, characterized by flexion of the first joint (PIP joint) and extension of the metatarsal phalangeal (MTP) joint. Very similar to a claw toe deformity.

Heel Counter: In shoes, the most posterior portion of the upper, which surrounds the heel of the shoe and grips the back of the heel bone. It is often reinforced.

Heel Wedge: In shoe manufacture, an elevated cushioned heel which decreases stress on the Achilles tendon.

Hemiplegic: One who has one arm and one leg on the same side of the body that is weak or paralyzed.

Hematoma: A collection of blood outside of a blood vessel.

Hylane Cartilage: Articular cartilage. Other types of cartilage are fibro cartilage and elastic cartilage.

Hyperkerotic Lesions: Calluses, soft corns, and hard corns.

Idiopathic: Isolated abnormality without obvious causes.

Ilio-Tibial Band Syndrome: Pain in the lateral (outside) edge of the knee, due to irritation of the ilio-tibial band over the femur. Most commonly seen in long distance runners.

Informed Consent: The process of educating a patient, such that he/she has a broad overview of a surgery, procedure, or treatment, resulting in an awareness of risks vs. benefits, expectations and alternatives, so that the individual can participate in the decision of accepting or rejecting such choices.

Ingrown Nail: Abnormality of the nail, penetrating the skin just past the nail grooves.

Instep: Arched middle portion of the human foot, especially the upper (dorsal) aspect.

Inter-phalangeal Joints: Joints between the bones of the toe.

Intrinsic Muscles: Those smaller muscles that exist entirely within the confines of the foot.

Invasive Treatment: Procedure which involves penetrating or entering the body.

Isometric Exercise: Contraction of a muscle without body movement (i.e the muscle contracts but does not change in length).

Isotonic Exercise: Contraction of a muscle by moving weight a distance, as in weight lifting.

Joint Capsule: Thickened connective tissue that forms the outermost joint layer. The joint capsule is usually lined with synovium - the thin tissue that secretes joint fluid (synovial fluid).

Keratin: Protein, primarily seen in cuticular tissue, most often in the nails and hairs.

Laser: Light Amplification of Stimulated Emission of Radiation. Used to treat a myriad of problems, most effectively warts. Not yet proven effective in treating other problems in the foot.

Lateral: On the side (outside); or furthest away from the midline of the body (opposite is "medial").

Lesser Toes: All toes other than the great toe.

Ligament: Attaches bone to bone, thus stabilizing joints.

Local Anesthetic: Desensitizes only the immediate area around the surgical site.

Mallet Toe: Flexed deformity of the last joint of a toe, accompanied by a callus at the tip of that toe.

Medial: Orienting towards the center line of the body, therefore referring to the inside edge of the foot or ankle.

Medial Malleolus: The medial prominence of the ankle, which is actually a part of the distal tibia.

Meniscal Cartilage: Generally refers to the two "C" shaped structures in each knee. Composed of fibrocartilage, which is to be distinguished from hyaline (articular) cartilage.

Metatarsals: Long bones of the midfoot proximal to the toes (phalanges). They are numbered from one to five, five being behind the little toe.

Metatarsal Adductus: Congenital curving inward of the feet.

Metatarsalgia: Pain under the metatarsal heads in the forefoot, usually directly or indirectly related to repetitive localized overload of this area of the foot.

Minimal Incisional Surgery (MIS): Performed through small incisions in the foot, frequently for the treatment of bunions and spurs. It can be a dangerous, and usually ineffective, form of treatment.

Magnetic Resonance Imaging (MRI): An advanced X-ray technique that can visualize not only bones, but soft tissue, ligaments, tendons, and cartilage. Due to the high degree of detail associated with many MRI scans, many abnormalities may be identified that are not a source of symptoms. This can lead to unnecessary treatment. Therefore, MRIs are most appropriately ordered when:
  1. The ordering physician wants to answer a specific question and:
  2. The answer to that question will change the management plan.

Muscle: Specialized tissue that, because of its contractility, moves joints by its attachment to bone via the tendon. This is accomplished by striated muscle, which is to be distinguished from smooth muscle, which controls digestion, etc.

Myelodysplasia: Congenital abnormality characterized by a lower spinal defect and varying degrees of muscle weakness in the legs. Spina bifida is an example of myelodysplasia.

Navicular Bone: One of the five bones of the midfoot. Best referred to as the tarsal navicular, to distinguish it from the carpal navicular (a.k.a scaphoid) in the wrist.

Navicular Syndrome: See Pre-hallax Syndrome

Neuroma: Generally implies a thickened and irritated nerve, as seen between the toes in a Morton's neuroma.

Neuromuscular: Very general term relating either to both nerves and muscles, or to the nerve supply of the muscle.

Non-Invasive Treatment: A procedure which does not involve entering the body.

NSAID: Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) are a class of medication, that often serve to decrease pain symptoms by dampening the body's inflammatory response.

Occlusive: A material which does not permit the foot, skin, etc. to "breathe".

Onychomycosis: Fungal infection of the nail.

Onychogryphosis: An excessively thickened and/or overgrown nail.

Orthosis: Device which a person wears or uses to help support, align, or accommodate a body part.

Os Calcis (calcaneus): Heel bone.

Osteoarthritis: Arthritis characterized by partial or complete loss of the cartilage (articular cartilage) covering a joint. It commonly occurs in individuals as they age, and most often affects the weight bearing joints, such as the hip and knee. In the ankle joint, osteoarthritis commonly results from a previous trauma, such as an ankle fracture.

Osteotomy: Cutting and repositioning bones.

Osteomyelitis: Infection of a bone.

Paraplegic: One who has a weakness or paralysis of the legs.

Paronychia: Infection at the edge of the nail, usually the result of an ingrown toe nail.

Pedorthist: Specialist in prescription footwear.

Peripheral Nerves: Nerves in the arms or legs, as opposed to those in or near the spinal cord and brain.

Peroneal Nerve: A branch of the sciatic nerve, which begins at the knee and courses down the outside and front (antero-lateral aspect) of the leg, to top of the foot.

Peroneus Brevis Tendon: Tendon which attaches at the base of the fifth metatarsal.

Pes Planus: Flat feet. It is commonly found in patients who develop symptomatic acquired adult flatfoot deformity.

Phalanges: Small bones that make up the toes (s: phalanx).

Phlebitis: Inflammation of the veins, usually in the legs.

Plantar: The sole of the foot.

Plantar Fascia: Strong fibrous tissue attached to the heel, extended along the sole and attached at the metatarsal heads.

Plantar Fibromatosis: Thickening of the plantar fascia, leading to modules in the sole of the foot.

Plantar Flexion: Downward motion of the ankle joint. Motion which pushes the foot and ankle down and propels the body forward.

Plantar Ulcer: A full thickness breakdown on the bottom or plantar surface of the skin.

Plastazote: A foam made of a cross-linked polyethlene material, which is characterized by its ability to deform over time based on the ongoing force it is exposed to. This means that this material will mold to the shape it is exposed to. For this reason, Plastazote has many uses, such as arch supports (particularly in diabetics), lining braces, and inserts for amputee limbs.

Podagra: Another older term for Gout.

Pre-hallax Syndrome: Also called Accessory Navicular Syndrome. An unusual extra bony extension of the navicular bone. An accessory navicular can cause pain at the fibrous interface between the extra bone and the navicular bone. A condition that commonly presents in adolescents with an accessory navicular. Alternatively, symptoms can occur due to the prominence of the bone on the inside of the foot.

Pronation: Turning out of the hindfoot. It is often associated with a flat foot. A certain amount of pronation during the stance phase is good, as it helps absorb shock during walking or running. However, too much pronation can tend to overload the tendons and soft-tissues on the inside of the ankle, potentially leading to conditions such as posterior tibial tendonitis.

Proprioceptive Sense: The bio-feedback from the extremities, which tells the brain where and in what position the body is in. Propriception is critical in balance. The proprioception of a joint, such as the ankle, can be significantly diminished following surgery or following an injury such as an ankle sprain. Therefore, proprioception training should be an important part of rehabilitation following an injury.

Prosthesis: Device which replaces or substitutes a body part.

Psoriatic Arthritis: Arthritis accompanied by an abnormal skin condition. It is characterized by an abnormally exuberant immune reaction to the lining of a joint(s).

Quadriplegic: Paralysis of both arms and legs.

Reiter's Syndrome: Arthritis accompanied classically by urethritis (inflammation and irritation of the ureathra) and conjunctivitis (inflammation of the eyes).

Resection Arthroplasty: Surgical procedure which removes part of a bone on one or both sides of a joint.

Rheumatism: A non-specific term for general joint pain.

Rheumatoid Arthritis: Swelling, discomfort, and stiffness of the joints and tendons, often beginning in the feet. This may be accompanied by the formation of rheumatoid nodules in the soft-tissues.

Rickets: Abnormality of calcium or phosphorus metabolism in infants' or children's growing bones. Most often due to insufficient vitamin D.

Sensory Nerves: Nerves which transmit pain, temperature changes, touch, etc.

Sesamoids: A bone which is enveloped within a tendon, as in the two bones under the first metatarsal bone.

Shin Splints: Leg pain around the shin bone (tibia) occurring after a period of activity. It has been proposed that the pain may be caused either by inflammation at the site where the lower leg muscles attach to the bone (periosteitis), or by mild compartment syndrome.

Splay Foot: Abnormally wide foot.

Sprain: an injury to the ligaments holding a joint together. For example, an Ankle Sprain is an injury to the ligament(s) stabilizing the outside of the ankle joint.

Strain: an injury to the muscle tissue itself, either as a result of a single acute injury (ex. Calf strain) or as a result of multiple microscopic injuries.

Supination: An inward turning of the foot. The opposite of pronation. It is common in people with high arched feet (subtle cavus foot). A supinated foot is often a stiffer foot than a flatfoot.

Synovitis: Inflammation of the synovium, which is the innermost lining of the joint. The synovium is responsible for secreting synovial fluid, the fluid that normally lubricates the joint. The synovium is normally a very thin sheet of tissue (only a few cell layers thick) however, when it becomes inflamed it can get quite thick and secrete excessive joint fluid. Conditions such as rheumatoid arthritis and Psoriatic arthritis are characterized by synovitis.

Talus: The talus is the main bone that helps connect the lower leg to the foot. The talus is one of the major bones helping to form the ankle joint. It is the lower bone of the ankle joint, and articulates with the end of the tibia (directly above it) and the fibula (above and to the outside). The talus has an unusual shape, and is almost 70% covered with articular cartilage. It has many tendons running past it, but no tendons attaching. It also has a notoriously poor blood supply, which leaves it vulnerable to avascular necrosis (AVN) when a significant talar fracture has occurred.

Talpes Equinovarus: Also called "Clubfoot". It is a congenital condition where the soles of a newborn face each other rather than each other.

Tarsal Coalition: An abnormal connection of bones of the hindfoot by cartilage tissue or by bony bridges. It results from a failure of these bones to fully separate when the baby is developing in the uterus. It may be symptomatic, although it usually presents as a stiff painful flatfoot deformity when children reach adolescence.

Tarsals: A series of bones in the foot, located at the root of the foot or "instep". The tarsals consist of the hind and midfoot and include the calcaneus, talus, navicular, cuboid, and the three cuneiform bones.

Tarsal Tunnel Syndrome: A condition characterized by irritation of the tibial nerve behind the medial malleolus (inside of the ankle).

Tendon: Band of strong fibers which connect muscle to bone.

Tendonitis: Inflammation of the tendon tissue or the sheath around a tendon.

Tendon Sheath: The channel through which a tendon runs or is located. A tendon sheath can vary between a thin sheath to a more firm tunnel. A tendon sheath often has a synovial lining, which secretes fluid to help lubricate the tendon and facilitate gliding of the tendon.

Tibia (shin bone): The long bone of the leg, from the knee to the ankle.

Transfer Lesions: Irritation developed due to weight or movement in a localized area (ex. Metatarsalgia).

Triple Arthrodesis: Procedure which solidly fuses together the three main bones of the hindfoot.

Trauma: Either direct or indirect. Indirect trauma results when the force is applied away from the actual part injured, such as a twisting motion. Direct trauma results when the force is fully directed at the injured part, such as being struck by a bat.

Valgus Angulation: When the distal part of the extremity moves away from the midline (the opposite of valgus is "varus"). For example, a person with "Knock Knees" would be said to have a valgus alignment at the knees.

Varus Angulation: When the distal part of the extremity moves towards the midline (the opposite of valgus is "varus"). For example, a person with "Bow Legs" would be said to have a varus alignment at the knees.

Verrucous Plantaris: Warts.

Xylocaine: A local anesthetic also known as Lidocaine 

Edited October 10, 2015


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