In the human foot, the

plantar Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

or volar plates (also called plantar or volar

ligament A ligament is the fibrous connective tissue that connects bones to other bones. It is also known as ''articular ligament'', ''articular larua'', ''fibrous ligament'', or ''true ligament''. Other ligaments in the body include the: * Peritoneal li ...

s) are

fibrocartilaginous Fibrocartilage consists of a mixture of white fibrous tissue and cartilaginous tissue in various proportions. It owes its inflexibility and toughness to the former of these constituents, and its Elasticity (physics), elasticity to the latter. It ...

structures found in the

metatarsophalangeal The metatarsophalangeal joints (MTP joints), also informally known as toe knuckles, are the joints between the metatarsal bones of the foot and the proximal bones (proximal phalanges) of the toes. They are condyloid joints, meaning that an ellipt ...

(MTP) and interphalangeal (IP) joints. The anatomy and composition of the plantar plates are similar to the

palmar plate In the human hand, palmar or volar plates (also referred to as palmar or volar ligaments) are found in the metacarpophalangeal (MCP) and interphalangeal (IP) joints, where they reinforce the joint capsules, enhance joint stability, and limit hy ...

s in the

metacarpophalangeal The metacarpophalangeal joints (MCP) are situated between the metacarpal bones and the proximal phalanges of the fingers. These joints are of the condyloid kind, formed by the reception of the rounded heads of the metacarpal bones into shallow cav ...

(MCP) and interphalangeal joints in the hand; the proximal origin is thin but the distal insertion is stout. Due to the weight-bearing nature of the human foot, the plantar plates are exposed to extension forces not present in the human hand. The plantar plate supports the weight of the body and restricts dorsiflexion, whilst the main collateral ligament and the accessory collateral ligament (together referred as the collateral ligament complex, CLC) prevent motions in the transverse and sagittal planes. The major difference between the plantar plates of the MTP and IP joints is that they blend with the

transverse metatarsal ligament The transverse metatarsal ligament is a narrow band which runs across and connects together the heads of all the metatarsal bones. It is blended anteriorly with the plantar (glenoid) ligaments of the metatarsophalangeal articulations. Its plantar ...

in the MTP joints (not present in the toes). The MTP joint of the first toe differs from those of the other toes in that other muscles act on the joint, and in the presence of two sesamoid bones. The plantar plate is firm but flexible fibrocartilage with a composition similar to that found in the menisci of the knee (composed roughly of 75%

type-I collagen Type I collagen is the most abundant collagen of the human body. It forms large, eosinophilic fibers known as collagen fibers. It is present in scar tissue, the end product when tissue heals by repair, as well as tendons, ligaments, the endomys ...

), and can thus withstand compressive loads and act as a supportive articular surface. Most of its fibers are oriented longitudinally, in the same direction as the plantar fascia, and the plate can thus sustain substantial tensile loads in this direction.

Metatarsophalangeal joints

At the metatarsophalangeal joint the plantar plate plays an important role in the foot's weight-bearing function. The plantar plate is attached to the proximal phalanx, to the major longitudinal bands of the

plantar fascia The plantar fascia is the thick connective tissue (aponeurosis) which supports the arch on the bottom (plantar side) of the foot. It runs from the tuberosity of the calcaneus (heel bone) forward to the heads of the metatarsal bones (the bone betw ...

, and to the collateral ligaments. Together with the collateral ligaments, it forms a soft tissue box which is connected to the sides of the metatarsal head. The plate from the substantial distal insertion of the plantar fascia and can withstand ''tensile'' loads in line with the fascia itself. The plate can withstand ''compressive'' loads from the metatarsal head because of the orientation of the fibers in its fibrocartilage. The skeleton of the foot rests on a multi-layered ligamentous system of beams and trusses that responds to weight-bearing on irregular surfaces. A transverse system at the MTP joints is formed by the plantar plates and the deep transverse metatarsal ligament. The strong, longitudinal fibres of the deep

are inserted along this transverse system to form a strong longitudinal system. The longitudinal system controls the longitudinal arches of the foot, whilst the transverse system controls the splay of the forefoot. Both systems are centered on the plantar plates and activated weight-bearing pressure on the metatarsal heads. The tendon of the

extensor digitorum longus muscle The extensor digitorum longus is a pennate muscle, situated at the lateral part of the front of the leg. Origin and insertion It arises from the lateral condyle of the tibia; from the upper three-quarters of the anterior surface of the body of t ...

extends the MTP joint by using the plantar

fibro Asbestos cement, genericized as fibro, fibrolite (short for "fibrous (or fibre) cement sheet") or AC sheet, is a building material in which asbestos fibres are used to reinforce thin rigid cement sheets. Although invented at the end of the 19t ...

aponeurotic An aponeurosis (; plural: ''aponeuroses'') is a type or a variant of the deep fascia, in the form of a sheet of pearly-white fibrous tissue that attaches sheet-like muscles needing a wide area of attachment. Their primary function is to join musc ...

structure as a sling. The muscle becomes a deforming force if the MTP joint is held in an extended position over a long time, such as in a

high-heeled footwear High-heeled shoes, also known as high heels, are a type of shoe with an angled sole. The heel in such shoes is raised above the ball of the foot. High heels cause the legs to appear longer, make the wearer appear taller, and accentuate th ...

. The muscle extends at the IP joints when the MTP joint is flexed or in neutral position. Flexion is primarily performed by intrinsic foot muscles; the second toe (the) is unique as it has two dorsal interossei but no

plantar interossei muscles In human anatomy, plantar interossei muscles are three muscles located between the metatarsal bones in the foot. Structure The three plantar interosseous muscles are unipennate, as opposed to the bipennate structure of dorsal interosseous muscles ...

. The lumbrical muscles, attached to the medial side of the lesser toes, act as unopposed adductor, but become insufficient plantar flexors with chronic extension.

Notes

References

* * * * * {{Authority control Ligaments of the lower limb