Dance Anatomy & Kinesiology

310 Dance Anatomy and Kinesiology

Individual Muscles of the Ankle and Foot

Anterior Crural Muscles

The anterior crural muscles are located on the front of the lower leg. They are contained within the

anterior compartment of the leg and include the tibialis anterior, extensor digitorum longus, extensor

hallucis longus, and peroneus tertius. Because these muscles all pass anteriorly to the axis of the

ankle joint, they have the common action of dorsiflexion. When the foot is free, this dorsiflexion can

be used to raise the toes and front of the foot and to prevent their striking the ground in movements

such as walking and running. Loss of the ankle dorsiflexors causes the foot to hang down, a condition

termed “drop-foot” (Smith, Weiss, and Lehmkuhl, 1996) when swinging the leg forward in walking. Loss

of the dorsiflexors also prohibits the desired smooth lowering of the foot to the ground during walking,

and a distinctive slap or clop occurs (Moore and Agur, 1995).

Tibialis Anterior

As its name implies, the tibialis anterior (tibial, tibia + anterior, toward

the front) originates from the front of the shin (figure 6.12). It runs down

the anterolateral portion of the shin and then crosses inward over the

top of the ankle to insert onto the medial undersurface of the foot (first

cuneiform and base of first metatarsal). The tibialis anterior is respon-

sible for the roundness of the lower leg in this region, and its paralysis

results in a flatness or even concavity in this area accompanied by an

excessively prominent anterior tibia (Smith, Weiss, and Lehmkuhl, 1996).

This muscle is a powerful dorsiflexor of the ankle-foot and is estimated

to provide 80% of the dorsiflexion power of the foot (Frey and Shereff,

1988; Scheller, Kasser, and Quigley, 1980). During weight bearing, this

dorsiflexion function can be used to bring the body weight forward over

the foot to prevent the body from falling backward or to ready the body

for an upcoming movement such as a quick rise onto the toes (Karpovich

and Manfredi, 1973). Due to its medial progression to the undersurface

of the foot, when the muscle contracts it is capable of producing slight

inversion of the foot as well as dorsiflexion. During movement when the

foot is weight bearing, this inversion function of the tibialis anterior helps

support the medial longitudinal arch and prevent excessive pronation.

Palpation: The tendon of the tibialis anterior can be easily seen and

palpated where it crosses the front of the ankle when the foot is actively

dorsiflexed. The upper belly of the tibialis anterior can be palpated on

the lateral side of the anterior margin of the tibia.

Attachments and Primary Actions of Tibialis Anterior

Muscle Proximal attachment(s) Distal attachment(s) Primary action(s)

Tibialis anterior

(tib-ee-A-lis)

Upper two-thirds of lateral tibia

and adjacent interosseous

membrane

Medial and inferior surfaces of

medial cuneiform and base

of first metatarsal

A-F dorsiflexion

Foot inversion

FIGURE 6.12 The tibialis anterior

(right foot, anterior view).