Dance Anatomy & Kinesiology

The Skeletal System and Its Movements 11

Joint Architecture

The human skeleton is composed of various bones
joined together to form segments or links. The
connection between adjacent bones or cartilage is
termed a joint or, more technically, an articulation.
These articulations have two primary but divergent
functions: to bind the skeleton together and to
provide mobility. There are many different kinds of
articulations, with varied types of connections and
motions present.

Classification of Joints

Joints can be classified according to the type of
connective tissue that binds them and the presence
or absence of a joint cavity (Marieb, 1995). In this
structure-based classification system there are three
classes of joints—fibrous, cartilaginous, and synovial
(see table 1.3).

Fibrous Joints

Fibrous joints are held tightly together by either very

short fibers (sutures), cords (ligaments), or sheets

(interosseous membranes) of fibrous connective tissue.

In each case, the fibrous connective tissue directly con-

nects the adjacent bones and there is no space between

the bones. Sutures allow no true movement, but only

“give,” while the other two types of fibrous joints allow a

variable amount of movement depending on the length

of their fibers. The type of connective tissue involved

(dense regular connective tissue) can withstand great

tensile stress. Examples of fibrous joints include the

sutures of the skull, the middle joint between the

bones of the forearm (middle radioulnar), and two of

the joints between the bones of the lower leg (middle

tibiofibular and distal tibiofibular joints).

Cartilaginous Joints

Cartilaginous joints are united directly by cartilage

(fibrocartilage or hyaline cartilage); and, similarly

TABLE 1.2 Bony Markings

Name Definition Example

Depressions and openings

Fossa A hollow or depression Iliac fossa

Foramen A hole or passage through a bone Obturator foramen of pelvis

Sinus A cavity or spongelike space in a bone Sinus tarsi in foot

Projections and processes that help form joints

Condyle Rounded projection at the end of a bone that enters into

formation of a joint

Condyles of tibia

Facet Smooth, flat area where a bone comes in contact with

another bone

Facets of vertebrae

Head Spherical projection beyond a narrow necklike portion

located at the end of a bone that enters into formation

of a joint

Head of femur

Projections and processes to which muscles attach

Crest A large ridge Crest of ilium

Epicondyle Eminence located above a condyle Epicondyles of femur

Line A less prominent ridge Linea aspera of femur

Malleolus A rounded process Lateral malleolus of fibula

Spinous process

or spine

A sharp spine-like projection Spine of scapula

Trochanter Very large projection Greater trochanter of femur

Tubercle A small rounded projection Lesser tubercle of humerus

Tuberosity A rounded projection Ischial tuberosity

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