yogabook / joints / metatarsophalangeal joint
Metatarsophalangeal joints
The metatarsophalangeal joints (articulationes metatarsophalangeae, MTP) are the joints in which the first(proximal) phalanges (phalanges) of the toes move relative to the respective proximal heads of the metatarsal bones (caput ossis metatarsi). Laterally, the metatarsophalangeal joints are stabilized by collateral ligaments.
The metatarsophalangeal joints are ball-and-socket joints, but their mobility is significantly restricted. The convex part is formed by the metatarsals, the proximal phalanges by the convex glenoid cavities. In contrast to the metatarsophalangeal joints of the fingers, dorsiflexions (extensions) of over 90° are physiological in the metatarsophalangeal joints of the toes. This mobility is pathological in the metacarpophalangeal joints of the fingers, for example in the context of hypermobility syndrome. The range of motion extends actively to approx. 70° dorsiflexion, passively to a good 90°. In the direction of plantar flexion of the metatarsophalangeal joints, only around 50° is available both actively and passively.
The metatarsophalangeal joint of the big toe is a special case with two plantar sesamoid bones: the lateral sesamoid bone is connected to the lateral head of the flexor hallucis bre vis, which also attaches laterally to the proximal phalanx.
The medial sesamoid bone is connected to the medial head of the flexor hallucis brevis and the abductor hallucis, which also attaches to the medial proximal phalanx. The
flexor hall ucis brevis is involved in the plantar flexion of the big toe and therefore in the rolling of the foot. The abductor hallucis is also involved with a certain plantar flexor effect.
When the sesamoid bones are displaced, the physiological kinetics are influenced by their displacement to the lateral and (at least as far as the lateral sesamoid bone is concerned, along the 1st metatarsal bone also to the dorsal)
is significantly impaired in the context of hallux valgus.
Like the fingers, the toes also have no adduction or abduction ability in the interphalangeal joints and therefore no muscles stabilizing in these directions, so that varus and valgus stress in the interphalangeal joints must be prevented in asanas in order to protect the collateral ligaments from damage.
Articulating bones
- Metatarsals(metatarsal bones)
- Phalanges(phalanges)
Pathology
Images