48 Yoga anatomY
The synovial membrane is wrapped by layers of connective tissue that form the joint
capsule, providing containment for the movement possibilities created by the mobility of
the hyaline cartilage and synovial fluid. On the very outside of the joint capsule are fibers
that thicken and organize themselves into straplike bands, the collateral ligaments. These
ligaments direct the force that travels through a joint and keep the movement on track.
Superficial to all these elements are the muscles that travel across the joint.
Balanced Joint Space
In a healthy, functional joint, the space between the two bones is balanced, and maintains
that balance throughout the full range of motion (ROM) in that joint. Balance is not the
same as symmetry, and maintaining balanced joint space^1 through the range of motion
doesn’t mean that the joint space is evenly distributed at absolutely every moment.
Balanced joint space is instead the product of a complex set of factors, including but
not limited to the contours of the articulating surfaces of the bones, the viscosity of the
synovial fluid, the resilience of the joint capsule and ligaments around the joint, and the
assorted contractions of the muscles around the joint. In a larger sense, the hydration of the
tissues, the efficiency of the circulatory system, the ability of the nervous system to sense
movement in the joint, and the quality of the mind’s attention contribute to this balance.
The layer of hyaline cartilage at the end of each bone is able to absorb a tremendous
amount of force and distribute that force into the trabeculae, the weight-bearing scaffold-
ing of the bone. This force then travels through bone and joint and bone and joint until it
meets a surface that can absorb the force, such as the earth, or it is discharged in some
movement through space, such as throwing a ball. That force could also be received and
transmitted to another structure, or dispersed in unhelpful ways through soft tissues.
When the joint space is not balanced through the full range of movement and force is
not distributed across the articulating surfaces, there is some wear and tear on the hyaline
cartilage. Like other tissues in the body, the hyaline cartilage constantly remodels itself and
can repair minor wear and tear without long-term consequences. (There are other tissues
in the body, such as muscles, that remodel at a faster rate than the hyaline cartilage.) If the
imbalance in the joint space is consistent and continuous over a long period of time, the
hyaline cartilage cannot repair itself and can eventually become damaged or worn away.
If the hyaline cartilage is worn away, the ends of the bones rub against each other. This
friction eventually stimulates the bones to grow unevenly, which causes more friction and
stress on the bones. This cycle of friction and growth can become quite painful and is one
cause of osteoarthritis.
Lack of balance in the joint space can arise for a variety of reasons. Sometimes people
are just born with joints that don’t line up efficiently. More often the challenge arises from
inefficient movement patterns that eventually lead to imbalances in the joint capsule and
ligaments, over- or underuse of the muscles surrounding the joint, or habitual patterns in
the nervous system. These habits are often perpetuated through familiarity and lack of
awareness. Even a perfectly appropriate idea, exercise, or image can be dangerous when
done for too long or in a way that excludes any other ideas. Our ideas about movement
are at fault as much as the bones and ligaments we are born with. For example, pulling
the shoulders back to open up the front of the chest is a common instruction. This is a
(^1) I first learned the concept of balanced joint space through Body–Mind Centering (BMC). It is fundamental to BMC’s
approach to repatterning movement in the skeletal and ligamentous systems.