Other Muscles/Tendons

Question 1

Lumbricals

-4 muscles on dorsal surface

Answer 1

Origins- from tendons of FDL, first from med side of tendon to 2nd toe, others from adjacent tendons of FDL
Insertion- med side of extensor hood and base prox phalanx

Innervations- Med lumbrical= Medial Plantar
Lateral 3= Lateral Plantar S2-3
Actions- flex MTP joint and extend IP joints
- prevents clawing of toes during propulsive phase of gait

Question 2

Abductor Hallucis

Answer 2

Origin- plantar aponeurosis and med tubercle of calcaneus
Insertion- med side base prox phalanx hallux

Innervation- Medial Plantar S1-2
Action- abducts hallux

Question 3

Abductor Digiti Minimi

Answer 3

Origin- tubercles of calcaneus and intermuscular septa
Insertion- lat side base of prox phalanx MT5

Innervation- Lateral Plantar S2-3
Action- abducts little toe

Question 4

Adductor Hallucis

Answer 4

Origins- Oblique head= plantar surfaces of bases of MTs2,3,4
Transverse head= plantar surfaces lat 3 MTP joints and ligts
Insertion- lat side base of prox phalanx of hallux

Innervation- Lateral Plantar S2-3
Action- adducts hallux

Question 5

Plantar Interossei

-3 small muscles on bottom of foot

Answer 5

Origins- plantar and medial aspects of MTs3,4,5
Insertion- med side base of prox phalanx of same toe

Innervation- Lateral Plantar S2-3
Action- adduct MTs 3,4,5 (move towards 2nd toe, midline of foot)

Question 6

Dorsal Interossei

-4 bipennate muscles

Answer 6

Origins- sides of adjacent MTs closest to 2nd toe, two heads that’ll merge into one insertion
Insertion- lat side prox phalanx of MTs 2,3,4 and med side of MT2

Innervation- Lateral Plantar S2-3
Action- abduct toes from midline of foot (2nd toe)

Question 7

Plantar Aponeurosis

-Spreads from calcaneus to end of distal phalanx of each toe

Answer 7

Origin- med process of calcaneal tuberosity
Insertions- heads of MTs blending with other structures

• covers all short, intrinsic muscles of the foot
• tight, inelastic, supports M/L arches of the foot

Question 8

Tendon Sheaths at Ankle

-where tendons go around a corner to reduce friction

Answer 8

• Flexor Retinaculum prevents Tib post, FDL and FHL from flicking around med mall
  
  • > tibial nerve splits into med/lat plantar nerves around this, as does post tib artery, but PTA stays on the med side of the FR

-Extensor Retinaculum has sup/inf bands to prevent extensor tendons from ‘bow stringing’ during DF/extension of toes