9-3a. 1&2 muscular layers - Conference

Question 1

which dermatome is on the lateral aspect of the plantar foot?

Answer 1

S1 dermatome

Question 2

which nerves serve the S1 dermatome, on the lateral aspect of the plantar foot?

Answer 2

• lateral calcaneal & lateral dorsal cutaneous nerves (from sural nerve) - proximally
• lateral plantar nerve - distally

Question 3

what nerve innervates the plantar heel area?

Answer 3

medial calcaneal branches

(from tibial nerve)

Question 4

which nerve innervates the distal aspect of the medial plantar foot/ toes 1-3 and 1/2 of 4?

Answer 4

medial plantar nerve

(from tibial nerve)

Question 5

which part of the plantar foot is innervated by the saphenous nerve?

Answer 5

middle of the medial plantar foot,

medial to the medial plantar nerve

Question 6

if glass penetrates the lateral aspect of the plantar foot, which structures are immediately at risk?

Answer 6

• Abductor digiti minimi
• Lateral plantar fascia/ aponeurosis (calcaneal ligament)

Question 7

what are the 3 muscles of the 1st layer?

Answer 7

2 ABductors, 1 Flexor

• ABductor digiti minimi
• Flexor digitorum brevis
• ABductor hallucis

Question 8

What is the innervation of the 3 muscles in the 1st layer? (medial –> lateral)

• ABductor hallucis
• Flexor digitorum brevis
• ABductor digitorum brevis

Answer 8

•Medial 2 are innervated by the medial plantar nerve

• ABductor hallucis
• *Flexor digitorum brevis

•Lateral 2* are innervated by the lateral plantar nerve

• *Flexor digitorum brevis
• ABductor digiti minimi

Question 9

which muscle of the 1st layer can be dually innervated?

which is it not always innervated by?

Answer 9

Though flexor digitorum brevis (FDB) can be dually innervated by the:

• medial plantar nerve
• lateral plantar nerve

* FDB may not always innervated by the lateral plantar nerve

Question 10

Review the 1st layer muscle origins:

ABdm

FDB

ABh

Answer 10

Question 11

summary of the 1st layer muscle origins:

3 key points

Answer 11

1. medial process and plantar aponeurosis are origin sites for all 3
2. lateral process is the only origin for Abductor digiti minimi
3. BOTH septa serve as an origin for Flexor digitorum brevis

Question 12

fibers of the Abductor digiti minimi/quinti that insert onto the MT5 base and shaft form which muscle?

Answer 12

ABductor ossis metatarsi digiti minimi

Question 13

ABductor digiti minimi/ quinti:

origin

insertion

actions

Answer 13

• origin:
  
  • lateral & medial processes of calcaneal tuberosity
  • lateral portion of plantar aponeurosis
  • lateral intermuscular septum
• insertion:
  
  • MTPJ capsule
  • Extensor expansion
  • MT5 head and PP5 base (as does FDMB)
• actions:
  
  • ABducts 5th digit
  • Plantarflexes MTPJ 5

Question 14

FLEXOR DIGITORUM BREVIS

origins

insertions

actions

Answer 14

• origins:
  
  • medial process of calcaneal tuberosity
  • central portion of plantar aponeurosis
  • medial & lateral intermuscular septa
• insertion:
  
  • both sides of the middle phalanges (2-5)
• actions:
  
  • plantarflexes MTPJs 2-5
  • plantarflexes proximal IPJs 2-5

Question 15

ABDUCTOR HALLUCIS

origin

insertion

actions

Answer 15

• origin:
  
  • Medial process of calcaneal tuberosity
  • Medial portion of plantar aponeurosis
  • Medial intermuscular septum
  • Flexor retinaculum
• insertion:
  
  • MTPJ capsule
  • plantar metatarsophalangeal ligament
  • extensor expansion
  • medial sesamoid
  • MT 1 head, and base of HPP
• action:
  
  • ABducts hallux
  • plantarflexes hallux at MTPJ

Question 16

review the relationship of the FHL and the FDL tendons

Answer 16

The flexor digitorum longus tendon crosses over the FHL tendon

Question 17

QUADRATUS PLANTAE:

origin

insertion

actions

Answer 17

• origin:
  
  • Medial head: medial surface of calcaneus, posteriorly
  • Lateral head: plantar surface of calcaneus, anterior to the lateral process.
• insertion:
  
  • lateral side of FDL tendon
• inn:
  
  • lateral plantar nerve
• action:
  
  • assists FDL in plantarflexion of the lateral MTP
  • plantarflexion of IP joints

Question 18

the lateral head of the quadratus plantae can also take origin from which deep ligament?

Answer 18

long plantar ligament

Question 19

other name for quadratus plantae?

Answer 19

flexor accessorius

Question 20

what structures run between quadratus plantar & flexor digitorum brevis muscles?

Answer 20

lateral plantar neurovasculature

Question 21

LUMBRICALS:

origin

insertion

Answer 21

• origin:
  
  • Flexor digitorum longus (FDL) tendons
• insertion:
  
  • Each lumbrical passes superficially/plantarly to the deep transverse MT ligament
  • Inserts onto the medial side of the respective extensor hood/wing (2-5th digits)

Question 22

LUMBRICALS:

innervation

major actions

Answer 22

• inn:
  
  • 1st = 1st common digital branch of medial plantar n.
  • 2nd-4th = deep branch/division of lateral plantar n.
• actions:
  
  • Simultaneously plantarflexes the MTPJ and dorsiflexes the IPJs of the lateral digits.

Question 23

side the specimen

Answer 23

LEFT SIDE

Question 24

where does the medial quadratus plantae muscle insert?

Answer 24

Inserts onto the flexor hallucis longus

Question 25

2 tendinous slips come from the quadratus plantae, and head toward what?

Answer 25

head towards the flexor digitorum longus' digital slips