2 Dance Anatomy and Kinesiology
W
e start our discussion of dance anatomy and
kinesiology in this book by looking at the skele-
tal system. The skeletal system provides the structural
framework of the human body, and its joints permit
the varied movements we explore in dance vocabu-
lary. In movements such as the high kick shown in
the photo on page 1, bones function in both their
support and movement functions. The bones and
associated joints of the gesture leg allow for the large
movement occurring at the right hip, while those
of the support leg are key for providing stability so
that the dancer can remain upright despite a very
small base of support. The support function of bones
requires that they be strong, and understanding of
bone remodeling is key for preventing loss in bone
strength commonly seen in female dancers. The
role of bones in joints is key for understanding and
describing human movement. Topics covered in this
chapter will include the following:- Primary tissues of the body
- Bone composition and structure
- Bone development and growth
- The human skeleton
- Joint architecture
- Body orientation terminology
- Joint movement terminology
- Skeletal considerations in whole body move-
ment
The concepts and terminology provided in this
chapter will be utilized and applied in more depth
in later chapters. Hence, this chapter can serve both
as an introduction and as a reference for when this
information is readdressed.Primary Tissues of the Body
The body is composed of four different primary tis-
sues, each with its own particular structure to help it
carry out its required functions. These four primary
tissues include muscle, nervous, epithelial, and con-
nective tissues. Muscle tissue is characterized by its
ability to contract and is found in the heart, in various
organs (e.g., in the smooth muscle in the gastrointes-
tinal tract), and in the many skeletal muscles of the
body. Nervous tissue is composed of cells (neurons)
that are able to generate and conduct electrical
messages, as well as other cells (neuroglia) that help
support these neurons. Epithelial tissue is composed
of cells that fit closely together to form continuoussheets, or membranes, that cover and line surfaces of
the body or form glands. Connective tissues gener-
ally function to bind, support, insulate, and protect
structures and can be further divided into connective
tissue proper, cartilage, bone, and blood.
While the first three types of tissues are composed
mainly of cells, connective tissue is characterized by
the presence of large quantities of nonliving material
in the space between connective tissue cells (extra-
cellular matrix; L. extra, outside of), which contains
different fibers and other constituents that dictate its
form and function. For example, bone has calcium
salts within its extracellular matrix that provide it
with the type of strength needed to support body
weight. Some types of connective tissue proper have
closely packed bundles of protein fibers (collagen),
giving them the type of strength necessary for their
function of binding bone to bone (ligaments) or
muscles to bones (tendons). Blood, the atypical con-
nective tissue, has plasma as its extracellular matrix;
its fibers become apparent only during the process
of blood clotting.
These primary tissues of the body can be grouped
together into anatomical or functional units called
organs. An organ is a structure that performs a spe-
cific function for the body and is composed of two
to four of the primary tissues. Examples of organs
are the heart and brain. Furthermore, organs that
work closely together for a common purpose can
be grouped according to a common function into
systems, including the skeletal system, muscular
system, and nervous system. The skeletal system will
be addressed in this chapter, and the muscular system
will be addressed in chapter 2. The skeletal system
is composed of all of the bones of the body, related
cartilages and ligaments, and the joints that connect
these bones together.Bone Composition and Structure
In the average individual, bone makes up about 15%
to 20% of total body weight (Huwyler, 1999). Bone
is characterized by its strength and rigidity, and it is
one of the strongest connective tissues in the body.
Unlike that of other tissues, the extracellular matrix
of bone contains calcium salts. These minerals com-
pose about 60% to 70% of bone weight (Hall, 1999;
Rasch, 1989) and impart to bone its great compres-
sive (L. pressus, to press together) strength, the ability
to resist a force that would tend to push together or
crush a bone. This extracellular matrix also contains
collagen fibers (G. koila, glue + gen, producing).