Musculoskeletal: Anatomy - Foot and ankle Flashcards
Proximal and distal attachment, innervation, and action of extensor digitorum brevis
Proximal: calcaneus, interosseous talocalcaneal ligament, stem of inferior extensor retinaculum
Distal: extensor tendons of 2nd-4th digits (not 5th!)
Innervation: deep fibular nerve (L5, S1)
Action: aids EDL in extending 2nd-4th digits at MTPJ and IPJ
What are the two muscles of the dorsum of the foot?
- Extensor hallucis brevis
- Extensor digitorum brevis
Proximal and distal attachment, innervation, and action of extensor hallucis brevis
Proximal: calcaneus, interosseous talocalcaneal ligament, stem of inferior extensor retinaculum
Distal: base of 1st proximal phalanx
Innervation: deep fibular nerve (L5, S1)
Action: aids EHL in extending great toe at MTPJ
Describe the arterial supply of the dorsum of the foot
By dorsalis pedis, with three named branches:
1. Lateral tarsal artery: supplies EDB and tarsal bones
2. Arcuate artery: supplies 2nd-4th toe clefts
3. First dorsal metatarsal artery: supplies 1st toe cleft and medial 1st toe, enters sole in 1st metatarsal space to become the deep plantar artery
Describe the venous drainage of the dorsum of the foot
By dorsal venous arch in subcutaneous tissue, which:
- Medially drains to great saphenous vein (pierces cribiform fascia and drains to femoral vein)
- Laterally drains to small saphenous vein (drains into popliteal which becomes femoral vein after passing through adductor hiatus)
Describe the motor and sensory supply of the dorsum of the foot
Motor by:
1. Deep fibular nerve: supplies EDB and EHB
Sensory by:
1. Deep fibular nerve: supplies 1st webspace
2. Superficial fibular nerve: supplies central dorsum (excluding 1st webspace)
3. Saphenous nerve: supplies medial foot (over 1st metatarsal)
4. Sural nerve: supplies lateral margin of foot
What is the deep fascia of the foot continuous with?
Proximally with the inferior extensor retinaculum
Distally with the plantar fascia
Describe the structure and anatomy of the plantar aponeurosis
Dense collagen fibres arranged mainly longitudinally
Arises from medial process of calcaneus and divides into five bands distally which are continuous with the fibrous tendon sheaths of the flexor tendons
Reinforced inferior to metatarsal heads by the superficial transverse metatarsal ligament
Describe the five components of the foot and their contents
In forefoot and midfoot:
1. Medial: abductor hallucis, flexor hallucis brevis and tendon of flexor hallucis longus, medial plantar nerve and vessels
2. Central: flexor digitorum brevis, tendons of flexor digitorum and hallucis longus, quadratus plantae, lumbricals, adductor hallucis, lateral plantar nerve and vessels
3. Lateral: abductor and flexor digiti minimi brevis
4. Dorsal: extensor hallucis and digitorum brevis, dorsal neurovascular structures
In forefoot only:
5. Interosseous: metatarsals, interossei, deep plantar and metatarsal vessels
Summarise the layers of the foot and their contents, from superficial to deep
- Abductor hallucis, flexor digitorum brevis, abductor digiti minimi
- Quadratus plantae, lumbricals, tendons of flexor hallucis and digitorum longus
- Flexor hallucis brevis, adductor hallucis, flexor digiti minimi
- Plantar and dorsal interossei, tendons of tibialis posterior and fibularis longus
Second and fourth layer have “uniquely” named foot muscles
Hallucis and digiti mini paired with same muscle types, with abductors superficial to flexors
Proximal and distal attachment, innervation, and action of abductor hallucis
Proximal: medial process of calcaneus, flexor retinaculum, plantar aponeurosis
Distal: medial base of 1st proximal phalanx
Innervation: medial plantar nerve (S2-3)
Action: great toe abduction and flexion
Which six intrinsic foot muscles are supplied by the lateral plantar nerve? Which of these are supplied by the superficial and deep branches?
1, 2. Flexor and abductor digiti minimi (flexor by superficial branch)
3. Adductor hallucis (deep branch)
4. Quadratus plantae
5. Lateral 3 lumbricals
6. Interossei (plantar and dorsal)
Which four intrinsic foot muscles are supplied by the medial plantar nerve?
1, 2. Flexor and abductor hallucis brevis
3. Flexor digitorum brevis
4. Medial lumbrical
Proximal and distal attachment, innervation, and action of flexor digitorum brevis
Proximal: medial process of calcaneus, plantar aponeurosis, intermuscular septa
Distal: both sides of 2nd-5th middle phalanges
Innervation: medial plantar nerve (S2-3)
Action: 2nd-5th digit flexion
Proximal and distal attachment, innervation, and action of abductor digiti minimi
Proximal: medial and lateral process of calcaneus, plantar aponeurosis, intermusfcular septa
Distal: base of 5th proximal phalanx
Innervation: lateral plantar nerve (S2-3)
Action: 5th digit abduction and flexion
Proximal and distal attachment, innervation, and action of quadratus plantae
Proximal: plantar surface of calcaneus
Distal: posterolateral margin of FDL tendon
Innervation: lateral plantar nerve (S2-3)
Action: assists FDL with 2nd-5th toe flexion
Proximal and distal attachment, innervation, and action of lumbricals
Proximal: tendons of FDL
Distal: extensor expansion
Innervation: lateral 3 by lateral plantar nerve (S2-3), medial 1 by medial plantar nerve (S2-3)
Action: flexion at MTPJ while assisting with maintaining extension at IPJ
Proximal and distal attachment, innervation, and action of flexor digiti minimi
Proximal: base of 5th metatarsal
Distal: base of 5th proximal phalanx
Innervation: lateral plantar nerve (S2-3)
Action: 5th digit flexion
Proximal and distal attachment, innervation, and action of adductor hallucis
Proximal: oblique head from base of 2nd-4th metatarsal, transverse head from plantar ligamants at MTPJ
Distal: lateral base of 1st proximal phalanx
Innervation: lateral plantar nerve (S2-3)
Action: great toe adduction, also assists in maintaining transverse arch