Fibularis Brevis Muscle Anatomy

Study Notes

Extends from the knee joint to the ankle joint
Bony framework consists of two parallel bones: tibia (medially) and fibula (laterally)

Divided into three compartments: anterior (extensor), posterior (flexor), and lateral (evertors)
Separated by interosseous membrane, two intermuscular septa, and direct attachment of deep fascia to the periosteum of the anterior and medial borders of the tibia

Contains muscles, blood vessels, and nerves
Muscles:
- Tibialis anterior
- Extensor hallucis longus
- Extensor digitorum longus
- Fibularis tertius
Blood vessels:
- Anterior Tibial Vessels
Nerves:
- Deep Fibular Nerve

Tibialis anterior:
- Origin: lateral surface of tibia and adjacent interosseous membrane
- Insertion: medial cuneiform and base of first metatarsal
- Action: dorsiflexion of foot at ankle joint and inversion of foot
- Nerve supply: deep fibular nerve (L4, L5)
Extensor hallucis longus:
- Origin: middle one-half of medial surface of fibula
- Insertion: dorsal surface of base of distal phalanx of great toe
- Action: extension of great toe and dorsiflexion of foot
- Nerve supply: deep fibular nerve (L5, S1)
Extensor digitorum longus:
- Origin: proximal one-half of medial surface of fibula
- Insertion: bases of distal and middle phalanges of lateral four toes
- Action: extension of lateral four toes and dorsiflexion of foot
- Nerve supply: deep fibular nerve (L5, S1)
Fibularis tertius:
- Origin: distal part of medial surface of fibula
- Insertion: base of fifth metatarsal
- Action: dorsiflexion and eversion of foot
- Nerve supply: deep fibular nerve (L5, S1)

Originates from the lower two-thirds of the lateral surface of the fibula
Tendon passes behind the lateral malleolus and across the lateral surface of the calcaneus to attach to a tubercle on the lateral surface of the base of the fifth metatarsal
Action: assists in eversion of the foot

Originates from the common fibular nerve in the popliteal fossa
Supplies the two fibular muscles and then penetrates deep fascia in the lower leg and enters the foot where it divides into medial and lateral branches
Supplies dorsal areas of the foot and toes except for the web space between the great and second toes, which is supplied by the deep fibular nerve, and the lateral side of the little toe, which is supplied by the sural branch of the tibial nerve

Thickening of deep fascia on the lower parts of the leg
Five retinacula: two extensor retinacula (upper and lower), two fibular retinacula (upper and lower), and one flexor retinaculum
Help to maintain the structures passing from the leg into the foot in their position and prevent their displacement