Q8-4. Dorsum of the Foot Flashcards
What dermatomes cover the dorsum of the foot?
S1 (lateral 1/3) and L5 (medial 2/3)
What two muscle tendons travel deep to the superior extensor retinaculum and the stem of the inferior extensor retinaculum?
Extensor digitorum longus and Fibularis tertius
What is the course of the cervical ligament?
Runs from the sulcus calcanei to the neck of the talus
Which ligaments have attachments to the lateral portion of the sulcus calcanei (floor of the sinus tarsi)?
- Cervical ligament
- Bifurcate ligament
- Inferior extensor retinaculum (three attachment sites)
- Interosseous talocalcaneal ligament
What muscles originate in the lateral portion of the floor of the sinus tarsi?
- Extensor digitorum brevis
- Extensor hallucis brevis
What is the innervation of the extensor digitorum & hallucis brevis
Lateral terminal branch of deep fibular nerve
What is the blood supply to the extensor digitorum & hallucis brevis?
Lateral tarsal artery
What are the origins of extensor digitorum brevis?
- Floor of sinus tarsi
- Inferior extensor retinaculum
- Interosseous talocalcaneal ligament
What tendons pass superficially to EDB muscle after it divides into 3 bellies?
Fibularis tertius and Extensor digitorum
What are the insertions of the three bellies of EDB?
The three bellies give rise to tendons to the 2nd-4th digits (occasionally 5th digit, too). Each tendon fuses with its respective EDL tendon as it crosses the proximal phalanx. The tendons terminate on the intermediate and distal phalanges.
What are the major actions of EDB?
Each tendon will dorsiflex its respective MPJ and (P/D)PJ
What are the main origin of the Extensor Hallucis Brevis?
In common with EDB:
- Floor of sinus tarsi
- Inferior extensor retinaculum
- Interosseous talocalcaneal ligament
What tendons pass superficially to the EHB muscle belly?
Fibularis tertius and Extensor digitorum
What is the insertion for EHB?
As it approaches the MPJ 1, it passes deep to the EHL tendon and inserts onto the base of the PP
What is the major action of the EHB?
Dorsiflexion of MPJ 1
En route to its insertion, what muscle, nerve, and artery does the EHB tendon pass over?
- 1st dorsal interosseous
- Medial terminal branch of deep fibular
- Dorsalis pedis/1st dorsal MT artery
What does the EHB tendon pass deep to after passing over the nerve/artery/muscle trio?
EHB tendon passes deep to the EHL tendon
** the two tendons do NOT fuse, they remain separate.
What compartment of the leg does the superficial fibular nerve supply?
Lateral compartment
When does the superficial fibular nerve become superficial?
@ inferior 1/3 leg
What are the cutaneous branches of the superficial fibular nerve?
- Intermediate dorsal cutaneous N.
- Medial dorsal cutaneous N.
What does the medial dorsal cutaneous N branch into once it enters the foot?
- Proper dorsal digital branch to the medial side of the hallux
- Common dorsal digital branch (to 2nd & 3rd digits)
What is the difference between “proper” and “common”?
“Proper” means that the nerve is going to one specific digit.
“Common” means that it is going to more than one digit.
What muscles does the lateral terminal branch of the deep fibular nerve innervate?
EDB and EHB
**sends a twig to the 2nd dorsal interosseous muscle (sensory only)
What travels with the lateral terminal branch of the deep fibular nerve?
The 1st and/or 2nd lateral tarsal arteries
