Dorsum - Book Flashcards
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
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.
the deep fascia of the dorsum is continuous with
plantar aponeurosis
where does the deep fascia of the dorsum attach?
peroneal trochlea cuboid tuerosity of 5th metatarsal laterally navicular tuberosity sustentaculum tali first metatarsal laterally
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
what tendons are bound in the sheath of the superior extensor retinaculum?
extensor digitorum longus extensor hallucis longus peroneus tertius tendon of tibialis anterior
where does the frondiform portion of the inferior extensor retinaculum attach?
dorsal and anterior aspect of the calcaneus just anterior to the sulcus calcanei
what is the usual shape of the inferior extensor retinaculum?
Y-shaped if it is x-shaped, it has an extra oblique superolateral band
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
fibers of the ________ root of the inferior extensor retinaculum continue medially to form the superomedial and inferomedial obique bands.
intermediate
what m. takes partial origin from the deep surface of the frondiform ligament?
extensor digitorum brevis m.
describe the deep and superficial layers of the superomedial oblique band of inferior extensor retinaculum. When the two layers fuse after passing the extensor hallucis longus tneson, it forms a tunnel for what?
tendon of the tibialis anterior superficial layer passes superficial to the tendon of the extensor hallucis longus, the anteiro tibial artery and ven and deep fibular n.
where does the superomedial oblique band of the inferior extensor retinaculum attach?
medially on the anterior surface of the medial malleolus
where does the inferomedial oblique band of the inferior extensor retinaculum attach?
plantar fascia; navicular tuberosity; medial cuneiform
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
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
the extensor expansions are formed by…
tendons of the extensor digitorum longus and brevis muscles
The extensor digitorum longus tendon divides into 3 slips. Describe where each slip goes.
central slip passes distally along the dorsum of the proximal phalanx and inserts on teh base of the middle phalanx the two lateral slips run along each side of the proximal and middle phalanges and converge over the distal end of the middle phalanx these rejoined tendinous slips pass distally as the terminal slip to insert on the base of the distal phalanx
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
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
what is an extensor hood?
long and short extensor tendons are held in place by two fibrous sheaths. these sheaths are continuous with each other and form a strong fibrous structure called the extensor hoods the more proximal part, called the extensor sling, is formed from fibers which encircle the digit to attach to a thickening in the plantar metatarsophalangeal ligament called the plantar plate the distal part of the extensor hood, called teh extenosr wing, is formed mostly from expansions of the tendons of the lumbrical muscles
how many plantar plates are there?
5
interosseous muscles contribute to the formation of the _______ but not of the ____ (Sling/Wing)
sling; wing
what is the function of the EDL?
- acting alone, it tightens the sling and loosens the wing - when the muscle contracts the plantar plate is pulled against the metatarsal head resulting in extension (or hyperextension) of the metatarsophalangeal joints - it CANNOT extend the interphalangeal joints - wing portion of the extensor hood is loose and the interphalangeal joints cannot be extended
what is the function of the lumbrical muscles?
- on contraction, they tighten the wing and loosen the sling allowing the more proximal parts of the extensor expansion to permit flexion at the metatarsophalangeal jt while holding more distal joints in extension - it should be noted that the FDL, because of its relationship with the lumbricals, does contribute to the function of the extensor hood
what is the function of the interosseous muscles?
abduction, adduction
on the first digit, what is attached to the extensor expansion?
only the tendon of the EHL – the plantar plate is attached to the deep transverse ligament on the lateral side only – a wing and sling are present, but lumbricals and interosei do not contribute to them – on medial side they are formed by the abductor hallucis, while on the lateral side, they are formed by the adductor hallucis and flexor hallucis brevis
what is the only intrinsic muscle of the dorsum of the foot?
extensor digitorum brevis
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
most medial tendon of the extensor digitorum brevis which crosses over the dorsalis pedis a.
sometimes a separate m. called the extensor hallucis brevis