10-2 Neurovasculature Distr. of Plantar Foot

Question 1

branches from which 3 major nerves supply entire skin of 2nd digit?

Answer 1

deep fibular nerve, superficial fibular, and medial plantar

Question 2

what are the SPECIFIC branches than innervate the skin of the 2nd digit?

Answer 2

proper dorsal digital (dorsomedial side), proper dorsal digital (dorsolateral side), and proper plantar digital (distal dorsum and plantar aspect)

Question 3

which nerve provides dermatome for 5th and lateral half of 4th toe on PLANTAR aspect?

Answer 3

lateral plantar

Question 4

which nerve supplies dermatome for MT 1- medial half of 4th toe on plantar aspect?

Answer 4

Medial plantar

Question 5

four intrinsic muscles supplied by medial plantar?

Answer 5

(LAFF) 1st lumbrical, abductor hallucis, flexor hallucis brevis, flexor digitorum brevis

Question 6

rami innervation for medial plantar nerve?

Answer 6

L4-S3 (same as tibial nerve)

Question 7

which is larger? medial plantar or lateral plantar?

Answer 7

medial plantar nerve

Question 8

what skin does the medial plantar innervate?

Answer 8

skin of sole, medial 3 toes and medial side of 4th toe; then branches make their way onto dorsum of the same 3.5 toes

Question 9

course of medial plantar

Answer 9

DEEP to Abductor hallucis to enter sole –> travels b/w fascial plane b/w Abductor hallucis and flexor digitorum brevis –> as AbH and FDB diverge –> gives off proper plantar digital nerve to medial side of hallux / great toe –> terminates at MT bases

Question 10

how does the Medial plantar terminate at the MT bases?

Answer 10

divides into 3 common plantar digital nerves (each one giving off 2 proper plantar digital nerves)

Question 11

lateral plantar nerve (rami, innervation, and cutaneous innervation)

Answer 11

S1-S3 rami; innervates most of intrinsic plantar muscles; inn some skin on lateral side; 1/2 of skin on plantar aspect of 4th toe and all of plantar skin of 5th toe; then branches make their way onto dorsum of same 1 1.5 digits

Question 12

course of lateral plantar nerve

Answer 12

deep to Abductor hallucis –> pierces medial IM sptum –> runs distally/laterally b/w FDB and QP –> pierces lateral intermuscular septum –> and divides proximal to MT 5 bases

Question 13

how does the lateral plantar nerve terminate?

Answer 13

proximal to MT 5 bases, divides into deep branch (hidden by QP), superficial branch (proper plantar digital nerve to lateral side of 5th toe, and common plantar digital nerve –> dividing into communicating branch and 2 proper plantar digital nerves)

Question 14

baxter’s nerve; branches off of what, and innervates which muscles?

Answer 14

1st branch off lateral plantar nerve; innervates flexor digitorum brevis, quadratus plantae, and abductor digiti minimi

Question 15

where are the 2 primary sites of entrapment for Baxter’s nerve?

Answer 15

(1) lateral turn b/w QP and thick fascia of AbDH, and (2) anterior course towards medial process, which can develop a spur

Question 16

morton’s plantar neuroma: define, where most common

Answer 16

interdigital nerve entrapment causing enlargement –> most often reported in 3rd common digital branch

Question 17

cause of morton’s neuroma?

Answer 17

can be abnormal biomechanics during stance phase that creates excessive tension & compression of nerves

Question 18

typical morton’s neuroma patient; and sxs

Answer 18

usually women (40-60 y/o, overweight); sxs incl. numbness, tingling, and/or radiating, burning pain in region of thickening (desc. as walking on a marble, hot pebble, or rolled up sock)

Question 19

clinical test for morton’s neuroma?

Answer 19

mulder’s test: compress forefoot while applying direct pressure to affected area (e.g. R hand squeezes MT heads together, L thumb applies direct pressure at affected web space where pt feels pain); you may hear a click

Question 20

tx for morton’s neuroma

Answer 20

neuroma excision

Question 21

posterior tibial artery branches

Answer 21

nutrient artery of the tibia; fibular artery; communicating branch, posterior medial malleolar artery, medial calcaneal branches

Question 22

which 3 intrinsic muscles of the plantar foot are supplied by the MEDIAL plantar artery?

Answer 22

ABductor hallucis

Flexor digitorum brevis

1st dorsal interosseous

Question 23

describe the course and terminal branches of the LATERAL PLANTAR ARTERY?

Answer 23

• courses deep to Abductor Hallucis –> pierces medial IM septum –> runs laterally and distally b/w FDB and QP –> pierces lateral IM septum –> can give off proper plantar digital artery to the lateral side of the 5th toe
• at MT 5 base, curves and becomes the DEEP plantar arch (b/w AdH oblique & interossei)
  
  • 3 posterior perforating arteries
  • 4 plantar metatarsal arteries
    
    • 1 anterior perforating artery each
    • 2 proper plantar digital arteries each
    • 1 digital branch or twig (from 1st plantar MT A only)

Question 24

course and terminal branches of MEDIAL plantar artery?

Answer 24

• courses deep to the Abductor hallucis
• runs b/w Abductor hallucis and Flexor digitorum brevis
• At MT 1 base, provides the PROPER PLANTAR DIGITAL ARTERY, which joins the digital branch or twig from the 1ST PLANTAR MT ARTERY to form –>
  
  • Proper plantar digital artery to the emdial side of the hallux
  • Superficial branches joins the 1st-3rd PLANTAR MT ARTERIES

Question 25

where do dorsal MT arteries lie, vs where do plantar MT arteries lie?

Answer 25

dorsal MT arteries lie in the intermetatarsal spaces; plantar MT arteries lie alone midline of MT shafe

Question 26

what does the POSTERIOR DORSAL PERFORATING ARTERIES branch off of?

Answer 26

dorsal MT arteries

Question 27

what does the POSTERIOR **PLANTAR** PERFORATING ARTERIES branch off of?

Answer 27

DEEP PLANTAR ARCH

Question 28

where does the anastomosis b/w Dorsal and Plantar posterior perforating arteries occur?

Answer 28

at base of MTs

Question 29

where does anastomosis b/w dorsal and plantar ANTERIOR perforating arteries occur?

Answer 29

base of proximal phalanx

Question 30

rule w/ relationship between artery and nerve?

Answer 30

**artery lies on the OUTSIDE of the same named nerve** (so medial plantar NERVE lies LATERAL to medial plantar artery, and lateral plantar nerve lies MEDIAL to lateral plantar artery)

Question 31

which muscle has dual innervation from medial and lateral plantar nerves?

Answer 31

flexor digitorum brevis

Question 32

which muscles are dually innervated by both lateral plantar and the deep fibular?

Answer 32

dorsal interosseus 1 and dorsal interossus 2

Question 33

which muscles of plantar foot are innervated by the MEDIAL PLANTAR?

Answer 33

1st lumbrical ABductor hallucis Flexor digitorum brevis Flexor hallucis brevis