Basic Anatomy

Last updated: 6/3/1997.

Introduction

There are 28 bones in the foot. There are two types of foot deformities common with CMT, pes cavus (clawfoot) and pes planus (flatfoot). Pes cavus is the more common deformity with CMT. This web page will be concentrating on pes cavus. These deformities are generally described in relationship of the arch, but the deformities are more complex. The literature is also not 100% in agreement on the exact nature of the deformity.

To understand the deformities, a better understanding of these bones and the terminology used is necessary.

Position and direction definitions

Planes: The body is divided into planes in order to discuss direction. See the planes figure for a pictorial presentation of the: medial, sagittal, coronal (frontal) and transverse (cross) planes.

Anterior or ventral refers to a structure being in front of another structure.

Posterior or dorsal refers to a structure being in back of another structure.

Medial refers to a structure that is closer to the center of the body in relationship to the medial plane.
Proximal refers to the part of a limb that is closer to the center of the body, or more accurately, closer to the center of the medial plane. Also refers to a structure being closer to the root of the limb.

Lateral refers to a structure this is further away from the center of the body with respect to the medial plane.
Distal refers to a part of the limb that is further from the center of the body, or more accurately, further from the center of the medial plane. Also refers to a structure being further from the root of the limb.

Analomy of the ankle

Bones

Smith's anatomy figures are included here. There are pointers to more (and better) figures at the end of this web page.

Foot bones
Leg bones

The bones of the foot are divided into three types:

Tarsal bones: talus, calcaneous, navicular, cubiod, medial cuneiform, intermediate cuneiform, and lateral cuneiform
Metatarsal bones: numbered one to five
Phalanges: the first big toe has two while the other toes have three

More definitions

Dorsiflexion

figure

Plantar flexion

Dropped foot a plantar flexion of the foot, generally due to loss of dorsiflexor muscles of the foot and toes.

Multiple definition of Pes Cavus:

Loss of the triceps surae permits the flexors to draw the calcaneus forward, the talus dorseflexes and the plantar fascia contracts. A high arch is formed. The long extentors of the toes tighten causing the toes to curl.
Another definition: excessively arched foot, high steppage gait, sometimes caused by an imbalance between the muscles flexing the toes and the muscles that extend the toes.
Another definition: high plantar arch, with retraction of the toes at the metatarsalphalangeal joints and flexion at the interphalangeal joints.

Muscles

TBD. Posterior thigh muscles

Medical Illustrator

ankle

Foot Talk

Foot anatomy

Viewpoint DataLabs anatomy 3D images

Viewpoint DataLabs sells 3D images, including images of the human anatomy. The web pages let you rotate the images.

Foot: woman's and man's
Foot bones: woman's and man's
Left leg: woman's and man's
Right leg: woman's and man's
Ankle: man's
Foot 3: man's

Neuromuscular physiology

For a short course in muscle physiology and design from the University of California at San Diego, press here.