- See:
Innerv. Musc. Lower Limb:
- Anatomy:
- tibial nerve is derived from
L4,
L5,
S1,
S2,
S3;
- the anterior component, supplies muscles of posterior thigh (except short
head of biceps whch is supplied by
peroneal nerve);
- in popliteal space it gives off branches that supply
popliteus muscle,
two heads of
gastrocnemius ,
soleus , &
plantaris muscles.
- nerve passes into
posterior compartment of leg to lie deep to the transverse crural septum;
- here, it supplies
tibialis posterior,
FHL , &
FDB;
- nerve passes behind medial malleolus to plantar side of foot and divides into medial and lateral plantar nerves:
-
medial branch: counterpart of
median nerve in hand;
- innervates the first
lumbricals,
abductor hallucis,
FDB, and
flexor hallucis brevis;
-
lateral branch: counterpart of the
ulnar nerve in the hand;
-
plantar muscles of the foot: are arranged in four layers w/ the
FDB lying most superficially, just under
plantar fascia;
- medial and lateral branches of
tibial nerve pass superficial to
abductor hallucis and the
quadratus plantae (w/ exception
of 1st branch of lateral plantar nerve);
- at the quadratus plantae, these nerve branches changes direction from verticle to horizontal;
-
first branch of lateral plantar nerve is the only branch to course deep to the
abductor hallucis and
FDB (but
superficial to
quadratus plantae) as it courses medially hugging the medial aspect of of the calcaneus,
adjacent to the heel spur, on its way to supply the quadratus, FDB, and
ADM;
- Posterior Nerve Block:
-
posterior tibial artery is palpated as a landmark;
- needle is passed adjacent to the achilles tendon toward the
posterior tibial artery behind the medial malleolus;
- after aspiration, 5 ml of anesthetic is required;
- to block posterior
tibial nerve, infiltrate just medial to achilles;
- insert the needle thru the deep fascia until it impinges on the bone behind the medial malleolus;
- Tibial Nerve Palsy:
- w/ tibial nerve palsy foot develops:
- cavus deformity due to plantar fascia contracture;
- lengthening of Achilles tendon rotating calcaneus into dorsiflexion;
- only
tibialis anterior is strong enough to produce active plantar flexion in presence of paralyzed triceps surae;
- Distal Tibial Tarsal Tunnel Syndrome:
Magnetic resonance
imaging for ineffectual tarsal tunnel surgical treatment.
