PATHIC MANIPULATIVE TREATMENT(OMT) often provide
relief. YOGAand PHYSICAL THERAPYare methods for
improving FLEXIBILITYand STRENGTHafter the initial
injury heals.
Risk Factors and Preventive MeasuresKey risk factors for back pain include occupational
risk (jobs that require heavy lifting, pushing, or
pulling), OBESITY, physical inactivity, and cigarette
smoking. Most back pain occurs as a result of injury
to the back, commonly strained muscles or
sprained ligaments. Regular physical exercise to
maintain strength and flexibility reduces the risk
for such injury and aids in weight loss efforts when
excessive body weight is a factor. Proper lifting
technique and good posture are also important.
See also ACUTE PAIN; ANKYLOSING SPONDYLITIS; CER-
VICAL SPONDYLOSIS; CHRONIC PAIN; CONDITIONING LIGA-
MENT; OSTEOARTHRITIS; SCIATICA; SPASM; SPINAL CORD
INJURY; TENDON.
Baker’s cyst A fluid-filled sac, also called a
popliteal cyst, that forms at the back of the knee.
The cyst develops when there is a tear in the syn-
ovial capsule (the membranous structure contain-
ing the fluid that lubricates the JOINT) that allows
synovial fluid to leak into the ears of least resist-
ance, which is the popliteal fossa. The leaking
fluid bulges out from the knee joint or forms a
connection with a BURSAin the back of the knee.
Either circumstance allows synovial fluid to col-
lect, forming a noticeable lump behind the knee.
A Baker’s cyst is soft to the touch and usually
painless, though a large cyst can be uncomfortable
or painful with movement or pressure.
NOTHING TO DO WITH BAKING
It is a common assumption that the term Baker’s
cyst has something to do with being a baker, just
as bricklayer’s shoulder tends to afflict bricklay-
ers and tennis elbow develops in people who
frequently play tennis (both conditions are forms
of BURSITIS). But Baker’s cyst takes its name from
the British surgeon who first identified it: William
Morrant Baker (1839–1896).When the cyst causes PAIN, the doctor may use
MAGNETIC RESONANCE IMAGING (MRI) to determine
whether other factors are involved. Occasionally a
Baker’s cyst is a symptom of a torn meniscus (CAR-
TILAGEin the knee), in which case treatment such
as surgery may be necessary. Nearly always a
Baker’s cyst eventually goes away without treat-
ment.
See also ARTHROSCOPY; BURSITIS; KNEE INJURIES;
OSTEOARTHRITIS; SYNOVITIS; TENDONITIS.bone The rigid tissue that gives the body struc-
ture and mobility. Bone consists of living cells con-
tained within a mineralized structure called the
bone matrix. Collagen fibers form intricate net-
works to which crystals of calcium phosphate, cal-
cium carbonate, and other mineral compounds
adhere, forming the dense and rigid structure
familiar as bone. Despite its density and its impres-
sion as a static structure, bone is in a perpetual
state of change, called remodeling. Throughout
life certain processes destroy old bone and other
processes construct new bone.Bone Cells
Three types of cells make up bone tissue:- Osteoblasts form new bone. In response to
stimulation from hormones such as CALCITONIN,
ESTROGENS, and TESTOSTERONE, osteoblasts draw
calcium and other minerals into the bone to
strengthen and solidify the bone matrix.
Osteoblasts produce a collagen-based substance
called osteoid. Calcium, phosphorus, magne-
sium, and other minerals bind with the osteoid
to form mineralized bone (the bone matrix). - Osteocytes make up the structure of existing
bone. Contained within the bone matrix, osteo-
cytes have a lifespan of 20 years or more.
Osteocytes begin their lives as osteoblasts, then
become enclosed in the bone’s mineralized
structure. The spaces they occupy within the
mineralized framework are lacunae. Each
lacuna has a rich BLOODsupply to nourish and
support the osteocytes. - Osteoclasts remove old bone. Osteoclasts derive
from monocytes and are phagocytic; they encir-
cle and consume cellular debris. As they con-
sume old bone tissue, osteoclasts release its
calcium into the blood circulation. PARATHYROID
bone 307