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Anterior and Lateral Leg - Details

Notes

Anterior and Lateral Leg - Details

Anterior & Lateral Leg Muscles

Key actions of the anterior and lateral compartment muscles:

  • Dorsiflexion — pull the dorsal surface (aka, top) of your foot towards the anterior leg to demonstrate this action.
  • Plantar flexion — push the ventral surface (aka, sole) of your foot towards the posterior leg to demonstrate this action.
  • Eversion — turn the ventral surface of your foot to face laterally to demonstrate this action.
  • Inversion — turn the ventral surface of your foot to face medially (towards the midline of the body) to demonstrate this action.

Anterior compartment leg muscles:

Fibularis tertius

  • Originates on distal fibula and interosseous membrane
  • Inserts on the base of the 5th metatarsal;
  • Dorsiflexes and everts the foot.

Extensor digitorum longus

  • Originates on the lateral tibial condyle, the interosseous membrane, and, the proximal 2/3rds of the fibula
  • Inserts on the bases of the middle and distal phalanges of digits 2-5
  • Extends the toes and dorsiflexes and everts the foot.

Extensor hallucis longus

  • Originates on the middle of the anterior fibula and interosseous membrane
  • Inserts on the base of the distal phalanx of digit 1
  • Extends the big toe and dorsiflexes and inverts the foot.

Tibialis anterior

  • Originates on the lateral tibial condyle and the interosseous membrane
  • Inserts on the first cuneiform and first metatarsal
  • Dorsiflexes and inverts the foot.

Lateral compartment leg muscles:

Fibularis brevis:

  • Originates on the distal lateral fibula (and intermuscular septa)
  • Inserts on the base of the fifth metatarsal
  • Everts and plantar flexes the foot.

Fibularis longus:

  • Originates on the lateral tibial condyle, head and proximal lateral fibula, and wraps under the foot
  • Inserts on the base of the first metatarsal and medial cuneiform
  • Everts and plantar flexes the foot.

Summary Points:

  • Extensors extend the toes
  • Hallucis acts on digit 1
  • Muscles that insert on the lateral side of the foot evert
  • Muscles that insert on the medial side of the foot invert
  • Anterior muscles dorsiflex
  • Lateral muscles plantar flex