Foot Anatomy

Question 1

7 tarsal bones

Answer 1

calcaneus
talus
navicular
cuboid
medial/intermediate/lateral cuneiforms

Question 2

ligaments of foot

Answer 2

lisfranc: medial cuneiform to 2nd MT
transverse MT
calcaneonavicular “spring”: maintains medial arch of foot

Question 3

Toe flexion (musc, inn)

Answer 3

FDL: L5-S1, tibial n.

FHL: L5-S1, tibial n.

FHB: S1-2, tibial n. → medial plantar n.

Question 4

Toe extension (musc, inn)

Answer 4

EDL: L4-5, deep fibular n.

EDB: L4-S1, deep fibular n.

EHL: L4-S1, deep fibular n.

Question 5

Toe adduction (musc, inn)

Answer 5

Adductor hallucis: S1-2, tibial n. → lateral plantar n.

Palmar interossei (3): S2-3, tibial n. → lateral plantar n.

Question 6

Toe abduction (musc, inn)

Answer 6

Abductor hallucis: S1-2, tibial n. → medial plantar n.

Dorsal interossei (4): S2-3, tibial n. → lateral plantar n.

Abductor digiti quinti pedis (ADQP): S1-2, tibial n. → inferior calcaneal n. (or LPN, depending on whom you ask)

Question 7

mnemonic for palmar/dorsal interossei

Answer 7

3 pads 4 dabs (same as hand)

palmar - adduction
dorsal - abduction

Question 8

Charcot foot/joint

Answer 8

poor sensation/proprioception → trauma and degeneration

e.g., diabetes → neuropathy → charcot foot

DDx w OA based on disfigurement

Question 9

March fracture

Answer 9

stress (marching) → MT stress fracture → distal foot pain/swelling

MRI sensitive

ORIF if displacement of if 5th MT involved (like hand Boxer fracture)

Question 10

Jones fracture

Answer 10

forceful inversion or adduction injury (crunches lateral foot on ground) → fracture across base of 5th MT

Tx: NWB v surgery per type/severity

Question 11

Nutcracker fracture

Answer 11

cuboid boin fracture

Question 12

Nutcracker cracks a _____

Answer 12

cube - nutcracker fracture = cuboid bone fracture

Question 13

Hallux rigidus

Answer 13

1st MTP joint arthritis d/t wear and tear

w/u: XR: joint space narrowing, osteophytes

Tx: high/wide toe box shoes, orthotics, NSAIDs, debridement

Question 14

Hallux valgus

Answer 14

genetics/narrow shoes → lateral deviation (excessive adduction) of big toe → painful medial 1st MTP bump/prominence/bunion

Question 15

Hammer toe

Answer 15

short shoes → PIP flexion to accommodate space

MTP extension, PIP flexion, DIP extension

like Boutonniere deformity w RA

Question 16

Mallet toe

Answer 16

shoes too small → DIP flexion; normal MTP/PIP

order XR to r/o extensor tendon avulsion/rupture

Question 17

Claw toe

Answer 17

neurologic disease (DM, CMT) → intrinsic foot muscle weakness → MTP extension, PIP flexion, DIP flexion

Question 18

Hammer v Mallet v Claw toes

Answer 18

Hammer: MTP extension, PIP flexion, DIP extension

Mallet: normal MTP/PIP, DIP flexion

Claw: MTP extension, PIP flexion, DIP flexion

Question 19

Turf toe

Answer 19

hyperextension injury (cutting on hard surface, sports) → 1st MTP joint sprain

exam: reproducible pain w hyperextension 1st MTP joint

Question 20

Lisfranc joint injury

Answer 20

athletic trauma → Lisfranc ligament (connects medial cuneiform to 2nd MT) injury/tear → dorsal foot pain in region of tarsometatarsal joint

Question 21

Morton neuroma

Answer 21

repetitive microtrauma to interdigital n. (usually bw 3rd/4th MTs) → interdigital benign growth of n. tissue → pain radiating bw two MTs, dysesthesias, paresthesias

positive Morton click on exam

Question 22

Plantar fasciitis

Answer 22

medial heel/arch foot → pulling tension like pain

worse in AM and taking 1st steps, improved w walking