CHAPTER
7
JOINTS
III. SAMPLE LECTURE OUTLINE
A. INTRODUCTION
1. A JOINT OR ARTICULATION, is a point of contact between bones, between cartilage and bone, or
between teeth and bones.
2. The structure of the joint determines how it will function.
3. The ranges of movements of a joint are IMMOVABLE, SLIGHTLY IMMOVABLE, or FREELY MOVABLE.
4. Articulations are supported by ligaments and joint capsules, as well as by the attachment of
surrounding muscles.
B. CLASSIFICATION OF JOINTS
1. The STRUCTURAL CLASSIFICATION of joints includes fibrous, cartilaginous, and synovial.
2. The FUNCTIONAL CLASSIFICATION of joints defines the DEGREE OF MOVEABILITY of the joint and includes
SYNARTHROSES (immovable joints), AMPHIARTHROSES (slightly movable joints), and DIARTHROSES
(freely movable joints).
C. FIBROUS JOINTS
1. The three types of fibrous joints are SUTURES, SYNDESMOSES, and GOMPHOSES. They are held closely
together by fibrous connective tissue and provide little or no movement.
2. SUTURES are found between the bones of the skull and are immovable. Functionally, they are
classified as synarthrotic joints. Examples of sutures are the coronal suture, lambdoidal suture, and
parietal suture.
3. SYNDESMOSES contain large amounts of fibrous connective tissue between the bones. They are
slightly movable and are functionally classified as amphiarthrotic joints. An example of a
syndesmosis is the distal articulation of the tibia and the fibula.
4. A GOMPHOSIS is a type of fibrous joint in which a cone-shaped peg fits into a socket such as the
articulations between the teeth and the bones of the mandible and the maxilla. Gomphoses are
always synarthrotic.
D. CARTILAGINOUS JOINTS
1. CARTILAGINOUS JOINTS are held together by cartilage and afford little or no movement. The two types
of cartilaginous joints are SYNCHONDROSES and SYMPHYSES.
2. A SYNCHONDROSIS is a joint in which the binding material is hyaline cartilage. Synchondroses are
functionally classified as synarthroses. Examples of synchondroses include the epiphyseal plate and
the articulation of the first rib and the sternum.
3. A SYMPHYSIS is joined by a broad, flat, fibrocartilagenous disc. It affords slight movement and is
classified functionally as an amphiarthrotic joint. Examples of a symphysis are the intervertebral
discs and the symphysis pubis.
E. SYNOVIAL JOINTS
1. The typical DIARTHROTIC JOINT contains a SYNOVIAL CAVITY lined with a SYNOVIAL MEMBRANE, an
ARTICULAR CARTILAGE, and an ARTICULAR CAPSULE. Most synovial joints contain accessory ligaments,
articular discs and bursae.
2. The ARTICULAR CAPSULE consists of an outer fibrous capsule and an inner synovial membrane. It
encloses the synovial cavity and unites the articulating bones.
3. The SYNOVIAL MEMBRANE secretes synovial fluid, which lubricates the joints and provides nourishment
for the articular cartilage.
4. Inside some synovial joints, such as the knee, are pads of fibrocartilage called ARTICULAR DISCS
OR MENISCI.
5. BURSAE are sac-like structures, which are situated between bones and several other structures such
as skin, tendons, ligaments, and muscles. Their function is to reduce friction between the moving
parts.
6. The presence of a JOINT CAVITY permits movement. This movement is limited due to the shape of the
articulating bones, tension of the ligaments and apposition of soft parts.
F. TYPES OF SYNOVIAL JOINTS
1. Synovial joints are divided into six subtypes. These are PLANAR, HINGE, PIVOT, CONDYLOID, SADDLE,
and BALL-AND-SOCKET.
2. PLANAR joints contain an articular surface which is flat and allows a gliding movement. Examples are
the joints between the carpals, tarsals, sternum and clavicle, and scapula and clavicle.
3. HINGE JOINTS allow one bone to move into the concave surface of another bone. These joints allow
for flexion and extension and are exemplified by the elbow and knee joints.
4. PIVOT JOINTS contain a round or pointed surface of one bone which articulates within a ring formed by
another bone. This allows for ROTATION and can be exemplified by the atlanto-axial joint.
5. CONDYLOID JOINTS contain oval-shaped bones which fit into a depression in another bone. This
allows for ABDUCTION and ADDUCTION as well as CIRCUMDUCTION.
6. SADDLE JOINTS are joints in which are one bone is shaped like a saddle and the other bone is shaped
like a rider Saddle joints permit side to side and up-down movements. This can be seen in the
trapezium of the carpus and the metacarpal of the thumb.
7. BALL & SOCKET JOINTS contain one bone with a ball surface and another with a cup-like depression.
These joints allow for ABDUCTION and ADDUCTION, ROTATION and CIRCUMDUCTION, FLEXION and
EXTENSION. They can been illustrated by the hip and shoulder joints.
G. TYPES OF MOVEMENT AT SYNOVIAL JOINTS
1. The major movements that occur at synovial joints are the following:

FLEXION—decrease in the angle between bones

EXTENSION—increase in the angle between bones

ABDUCTION—movement of a bone away from the midline

ADDUCTION—movement of a bone toward the midline

CIRCUMDUCTION—movement of the distal end of a part of the body in a circle
2. ROTATION – a bone revolves around its own longitudinal axis.
3. Specialized movements that occur at synovial joints include the following:

ELEVATION—upward movement of a body part

DEPRESSION—downward movement of a body part

PROTRACTION—movement of the body part is forward

RETRACTION—movement of the body part is backward

INVERSION—movement of the sole medially

EVERSION—movement of the sole laterally

DORSIFLEXION—movement of the foot in the direction of the dorsum (superior surface)

PLANTARFLEXION—movement of the foot in the direction of the plantar surface

SUPINATION—forearm movement so that the palms are forward or upward

PRONATION—forearm movement so that the palms are backward or downward
H. KNEE JOINT
1. The knee joint represents the most complex of the synovial joints, and contains many structural
features.
2. The main structures of the knee are as follows:
I.

ARTICULAR CAPSULE

PATELLAR LIGAMENT

OBLIQUE POPLITEAL LIGAMENT

ARCUATE POPLITEAL LIGAMENT

TIBIAL COLLATERAL LIGAMENT

FIBULAR COLLATERAL LIGAMENT

ANTERIOR CRUCIATE LIGAMENT

POSTERIOR CRUCIATE LIGAMENT

MEDIAL MENISCUS

LATERAL MENISCUS

BURSAE
COMMON DISORDERS
1. RHEUMATISM refers to any painful state of supporting structures of the body such as bones,
ligaments, tendons,
joints, and muscles.
2. ARTHRITIS refers to several disorders characterized by inflammation of joints accompanied by
stiffness.
3. RHEUMATOID ARTHRITIS (RA) is an autoimmune disease and is characterized by an inflammation of
the synovial membranes.
4. OSTEOARTHRITIS is a degenerative joint disease characterized by deterioration of the articular
cartilage. It is non-inflammatory and generally affects the weight-bearing joints.
5. GOUTY ARTHRITIS is a condition in which sodium ureate crystals are deposited in the soft tissues of
joints, causing inflammation, swelling, and pain.
6. A SPRAIN is a forcible wrenching or twisting of a joint that stretches or tears its ligaments without
dislocation.
7. A STRAIN is a stretched or partially torn muscle.