- Anatomy:
-
lateral compartment
-
plantar muscles of the foot:
-
origin:
- lateral condyle of tibia, head and proximal 2/3 of lateral surface of fibula, intermuscular septa and adjacent fascia;
-
course:
- peroneus longus courses posteiror to the brevis tendon, and then both tendons pass thru the common peroneal
synovial sheath, about 4 cm proximal to the lateral malleolus;
- synovial sheath passess through a fibro-osseous tunnel that is stabilized by the superior peroneal retinaculum and by
the calcaneofibular ligament;
- after the peroneus longus emerges from its sheath and passes inferior to the cuboid on its way to its insertion;
- os peroneum is an
accessory bone which is located within the peroneus longus tendon in about 20% of feet;
- typically this is located plantar to the cuboid, near the calcaneo-cuboid articulation;
- this accessory ossicle may be associated with peroneus longus tenosynovitis;
-
insertion:
- lateral margin of plantar surface of 1st cuniform and proximal end of 1st metatarsal.
-
action:
- primary action is to plantar flex the first ray of the foot;
- plantar flexion and eversion of the foot at the ankle;
- primarily active during the
stance phase of gait;
- gives lateral stability to the ankle;
- synergists:
gastrocnemius,
soleus;
-
nerve supply:
-
peroneal,
S1 >
L5,
L4; (see
innervation)
Pathologic Conditions:
-
peroneal tendon subluxation:
- peroneal tendon disruption:
- persistent swelling along the peroneal tendon sheath is a reliable sign for peroneus brevis tendon tear;
- peroneal muscle spasm:
- may occur w/
tarsal coalition, but may also occur w/ rheumatoid arthritis,
osteochondral frx,
& infection in subtalar joint or neoplasm (osteoid osteoma, fibrosarc)
-
Charcot Marie Tooth:
- when there is loss of the tibialis anterior and peroneus brevis (which is common in CMT), the peroneus longus
will cause flexion of the first ray, which subsequently leads to a
cavus foot deformity;
-
polio:
- in polio syndrome, transfer of the peroneus longus in the presence of strong
tibialis anterior results
in a dorsal bunion as the forefoot supinates;
- it must be combined with lateral transfer of the tibialis anterior to the base of the second metatarsal bone;
Peroneal tendon injuries.
HD Clarke MD et al.
Foot and Ankle Internation.
Vol 19. No 5. May 1998. p 281.
