Plantar - Book Flashcards
innervation abductor digiti minimi
lateral plantar n.
function abductor digiti minimi
abduct and flex 5th digit
you find an accessory insertion into the base of the 5th metatarsal - what m. is this?
abductor os metatarsi digiti minimi
muscles of first layer
1) abductor hallucis
2) flexor digitorum brevis
3) abductor digiti minimi
muscles of second layer
1) quadratus plantae
2) lumbricals
origin of quadratus plantae
*Two heads separated by long plantar lig Medial head - larger - medial process of plantar surface of calcaneus Lateral head - lateral process of calcaneus
insertion of quadratus plantae
Tendon of flexor digitorum longus
innervation of quadratus plantae
Lateral plantar n
function of quadratus plantae
- accessory flexor of the lateral 4 toes
- helps the flexor digitorum longus by putting tension on its tendons and straightening the line of pull of the long flexor
variations in the quadratus plantae
either the lateral head or the entire m. may be absent
how many lumbricals are there?
4 - numbered from medial to lateral
what is the origin of the lumbricals?
- all take origin from tendons of flexor digitorum longus - 2, 3, and 4 also arise from adjacent sides of flexor tendons
only origin of the first lumbrical
medial side of the most medial tendon only
the lumbricals cross the medial side of the metatarsophalangeal joint and continue …
along the medial side of the digits
all the lumbricals course _____ to the deep transverse metatarsal ligament
superficial
insertion of lumbricals
- medial surface of the extensor expansion dorsal to horizontal plane
- first lumbrical inserts on the extensor expansion of the second digit, second on third, third on fourth , and fourth on fifth digit
the lumbrical tendons form part of the ________ of the extensor hood
wing
innervation to lumbricals
1st: medial plantar n. Others: deep branch of the lateral plantar n.
function of lumbricals
- flex the metatarsophalangeal joints and extend the interphalangeal joints
variations in the lumbricals
- one or more may be absent
- 3rd or 4th may be doubled
- may insert directly into bone of proximal phalanx instead of extensor expansion
third layer of muscle
1) flexor hallucis brevis
2) adductor hallucis
3) flexor digiti minimi brevis
fourth layer of muscle
plantar interossei (3) dorsal interossei (4)
origin of lateral head of flexor hallucis brevis
1) cuboid near peroneal groove
2) area of lateral cuneiform adjacent to cuboid
3) occasionally from long and short plantar ligs
origin of medial head of flexor hallucis brevis
Deep –> tendon of Tibialis Posterior m.
Superficial –> intermuscular septum between medial and lateral compartments