Manual 34-42: Dorsum of Foot Flashcards
what skin is supplied by the medial terminal branch ?
- in the first intermetatarsal space, it divides into 2 dorsal digital n. which supply the skin of adjacent sides of the 1st and 2nd digits
where does the superior extensor retinaculum attach?
laterally – to the distal end of the fibula on its anterior border AND on the lateral surface of the lateral malleolus medially – anterior crest of the tibia and to the medial malleolus it blends with superior peroneal retinaculum laterally, and with the proximal border of the inferior extensor retinaculum and the flexor retinaculum medially
origin of the extensor digitorum brevis
- tubercle on the superolateral surface of the calcaneus just anterior to the sinus tarsi, from the interosseous talocalcaneal ligament and from the frondiform ligament
what do the extensor expansions look like on fifth digit?
for the fifth digit, tendons of the abductor digiti minimi and flexor digiti minimi contribute to the lateral aspect of the expansion
function of extensor digitorum brevis
- aid to extensor digitorum longus in extension of the phalanges of the 2nd, 3rd and 4th digits - if contraction continues, it also extends the metatarsophalangeal joints - when acting without the lumbricals, the extensors extend the MP joints by tightening the extensor sling and pulling the plantar pad against the proximal phalanx
innervation to extensor digitorum brevis
- lateral terminal branch of the deep peroneal n. most commonly *** however, when an accessory peroneal branch of the superficial peroneal n. is present (20% of cases) it usually aids in innervating the muscle
describe the medial tarsal a.
- small and variable - usually 2 - originate from dorsalis pedis opposite the origin of the proximal lateral tarsal a. - supply medial aspect of tarsal bones and terminate by contributing to medial malleolar rete
The deep fascia divides the dorsum of the foot into three layers. what does each layer contain?
superficial: tendons and accompanying synovial sheaths of the tibialis anterior, extensor hallucis longus, extensor digitorum longus and peroneus tertius muscles intermediate: extensor digitorum brevis m. deep: dorsalis pedis a. and branches, deep peroneal n. and branches, veins accompanying the dorsalis pedis, and termination of the perforating branch of peroneal a.
fibers of the ________ root of the inferior extensor retinaculum continue medially to form the superomedial and inferomedial obique bands.
intermediate
where do the intermediate and medial roots of the inferior extensor retinaculum attach?
intermediate - deeper portions of sulcus calcanei medial/deep - sulcus tali posterior to attachment of interosseous talocalcaneal ligament
the inferomedial oblique band of the inferior extensor retinaculum passes _________ to the dorsalis pedis a, deep peoneal n and tendons of the EHL and TA.
superficially
how many interosseous branches does the lateral terminal branch have?
three interoseous branches which serve the tarsal joints and the metatarsophalangeal joint of digits 2, 3 and 4
what does the medial dorsal cutaneous n. give rise to? ***
- one dorsal digital branch (1st dorsal digital n) - one common dorsal digital branch (1st common dorsal digital n)
dorsalis pedis fascia is the continuation of _______
crural fascia the deep fascia (dosalis pedis fascia) is the continuation of the deep fascia (crural fascia) of the leg
describe the path of the deep plantar a.
- arises from dorsalis pedis at the proximal part of first interosseous space - penetrates fist dorsal interosseous m. to reach plantar side of foot where it joins with first plantar metatarsal a of deep plantar a - occasionally the first plantar metatarsal,instead of originating from deep plantar arch, is a branch of or a direct continuation of deep plantar a.
where does the frondiform portion of the inferior extensor retinaculum attach?
dorsal and anterior aspect of the calcaneus just anterior to the sulcus calcanei
In _____ % of cases, this artery originates from the dorsalis pedis a at the level of the first tarsometatarsal jt
65% - arcuate a. in other cases, its origin can be slightly more proximal and therefore can be confused with distal lateral tarsal a.
where does the inferomedial oblique band of the inferior extensor retinaculum attach?
plantar fascia; navicular tuberosity; medial cuneiform
the superolateral oblique band of the inferior extensor retinaculum is present in about…
25% of persons it extends from the superomedial oblique band and frondiform ligament laterally to attach on the lateral surface of the lateral malleolus will merge with superior extensor retinaculum and the superior peroneal retinaculum
terminal branches of dorsalis pedis
- deep plantar - first dorsal metatarsal a.
where does the superficial peroneal n. come from?
- one of two terminal branches of common peroneal - arises deep to peroneus longus m. and passes inferiorly - penetrates through crural fascia and divides into two terminal branches
how many significant branches are there off the dorsalis pedis a.?
lateral tarsal medial tarsal arcuate 1st dorsal metatarsal a. deep plantar
tendons of the EDB join the EDL at the level …
of the metatarsophalangeal joints on the fibular side just proximal to their division into three slips
insertion of extensor digitorum brevis
- extensor hallucis brevis inserts on dorsal surface of the base of the proximal phalanx of the first digit - other 3 tendons insert into the lateral surface of the tendons of the extensor digitorum longus muscles of the 2nd, 3rd, and 4th digits, just distal to the metatarsophalangeal joints
how many plantar plates are there?
5
what percentage of people have a small and difficult to locate dorsalis pedis?
5-10% ` in cases where the artery is deficient or absent, the plantar arteries or teh perforating branch of the peroneal a. take over
the intermediate dorsal cutaneous n. divides into …
- 2nd and 3rd common dorsal digital n. - for intermetatarsal spaces 3 and 4 - each common dorsal digital branch divides to give rise to two dorsal digital n.
what is the only intrinsic muscle of the dorsum of the foot?
extensor digitorum brevis
what is the function of the interosseous muscles?
abduction, adduction
interosseous muscles contribute to the formation of the _______ but not of the ____ (Sling/Wing)
sling; wing