- See:
Anterior Compartment:
- Anatomy:
- origin: lateral condyle of tibia, proximal 2/3 of lateral surface of tibia, interosseous membrane,
deep fascia and lateral intermuscular septum;
- insertion: plantar surface on base of first metatarsal and medial plantar surface of 1st cuneiform;
- action: dorsiflexes and inverts foot at the ankle;
- reversed origin insertion action:
- when standing, the foot is fixed & becomes origin;
- action causes forward body lean antagonistic to plantar flexion of
soleus and
gastrocnemius;
- active in balance mechanism of anterior and posterior sway;
- nerve supply:
peroneal,
L4 >
L5,
S1;
(see
Innervation)
- synergists:
extensor hallucis longus,
externsor digitorum longus;
- Discussion: Paralysis:
- may occur from
polio;
- paralysis results in loss of dorsiflexor & invertor power & results in development of equinovalgus deformity;
- this is seen initially during swing phase of gait as moderate equinovalgus with forefoot eversion;
- later w/ more severe disease this will be seen in both phases of gait;
- to compensate, long toe extensors, function as dorsiflexors & become overactive during swing phase;
- hyperextension of the proximal phalanges and depression of the metatarsal heads results;
- contracture of ankle gradually develops as functioning triceps contracts;
- occassionally, the unopposed activity of the
peroneus longus, which depresses the first metatarsal, combines with
an active tibialis posterior to cause the formation of a cavovarus deformity;
-
treatment:
- transferthe
EHL tendon to bases of the first metatarsal;
- when
peroneus tertius is functioning, it may be transferred along w/
EHL to
the base of the first metatarsal;
- plantar fasciotomy may be needed
- when foot is severly relaxed or when the valgus deformity is fixed, tendon transfer is combined w/ triple arthrodesis ;
- Ruptured Tibial Anterior:
- symptoms of a ruptured tibialis anterior tendon are a sudden sharp
pain and swelling over the first cuniform, accompanied by an
inability to coordinate normal foot motion;
- Role of Tibialis Anterior in Club Foot:
- anterior tibial muscle has a strong supinatory action when abnormal
relationship between the talus & calcaneus is not been corrected;
The results of transfer of the tibialis anterior to the heel in patients who have a myelomeningocele.
Adult-onset hemiplegia : changes in gait after muscle-balancing procedures to correct the equinus deformity.
Posterior transfer
of the anterior tibial tendon in children who have a myelomeningocele.
Combined split anterior tibial-tendon
transfer and intramuscular lengthening of the posterior
tibial tendon. Results in patients who have a varus deformity of the foot due to spastic cerebral palsy.
Pathophysiology
of Charcot-Marie-Tooth disease.
Transfer of the tibialis anterior for calcaneus deformity in myelodysplasia.
