CH9.1-9.7 (EXAM3) Flashcards
Joint
is the place of contact between bones, between bone and cartilage, or between bones and teeth.
Articulation
Joint or connection between bones.
A Fibrous Joint
has no joint cavity and occurs where bones are held together by dense regular (fibrous) connective tissue.
A Cartilaginous Joint
has no joint cavity and occurs where bones are joined by cartilage.
A Synovial Joint
has a joint cavity (filled w/lubricating fluid) that separates the articulating surfaces of the bones. The articulating surfaces are enclosed within a CT capsule, and the bones are attached to each other by various ligaments.
Structural Characteristics of Fibrous
Dense regular CT holds together the ends of bones and bone parts; no joint cavity
Structural Characteristics of Cartilaginous
Pad of cartilage is wedged between the ends of bones; no joint cavity.
Structural Characteristics of Synovial
Ends of bones covered with articular cartilage; joint cavity separates the articulating bones; joint enclosed by an articular capsule, lined by a synovial membrane; contains synovial fluid.
Synarthrosis
Is an immobile joint. Two types of fibrous joints and one type of cartilaginous joint are synarthroses.
Amphiarthrosis
Is a slightly mobile joint. One type of fibrous joint and one type of cartilaginous joint are amphiarthroses.
Diarthrosis
Is a freely mobile joint. All synovial joints are diarthroses.
Structural Categories of Fibrous
Gomphosis
Suture
Syndesmosis
Structural Categories of Cartilaginous
Synchondrosis
Symphysis
Structural Categories of Synovial
Plane Hinge Pivot Condylar Saddle Ball-and-socket
Functional Classifications of Fibrous
Synarthrosis (immobile) or Amphiarthrosis (slightly mobile
Functional Classification of Cartilaginous
Synarthrosis (immobile) or Amphiarthrosis (slightly mobile
Functional Classification of Synovial
Diarthrosis (freely mobile)
Gomphosis
Resembles a “peg in a socket.” The only gomphoses in the human body are the articulations of the roots of individual teeth w/ the alveolar processes (sockets) of the mandible and the maxillae. Periodontal membranes hold a tooth to bony jaw (synarthrosis)
Sutures
are fibrous joints found only between certain bones of the skull; are functionally classified as synarthroses, since they are immobile joints. Sutures have distinct, interlocking, usually irregular edges that both increase their stability and decrease the number of fractures at these articulations. Sutures permit the skull to grow (by new bone being deposited at these sutures) as the brain increases during childhood. In an older adult, the dense regular CT in the suture becomes ossified, fusing the skull bones together.
Synostoses
When bones have completely fused across the suture line, these obliterated sutures are now called synostoses.
Syndesmoses
are fibrous joints in which articulating bones are joined by long strands of dense regular CT only; amphiarthrosis (slightly mobile); found between radius and ulna and between tibia and fibula. The shafts of two articulating bones are bound by a broad, ligamentous sheet called an interosseous membrane (interosseous ligament). The interosseous membrane provides a pivot where the radius and ulna (or the tibia and fibula) can move relative to one another.
Synchondrosis
An articulation in which bones are joined by hyaline cartilage; functionally are immobile (synarthrosis).
The hyaline cartilage of epiphyseal plates in children forms…
synchondroses that bind the epiphyses and diaphysis of long bones.
When the hyaline cartilage stops growing, bone replaces…
the cartilage and synchondrosis no longer exists.
The spheno-occipital synchondrosis is found between…
the body of the sphenoid and the basilar part of the occipital bone.
Examples of Synchondroses involve…
The Costochondral Joint and First Sternocostal Joint,
The Costochondral Joint
Is the joint between each bony rib and its respective costal cartilage.
The Sternocostal Joint
The attachment of the first rib to the sternum by costal cartilage; here, the first rib and its costal cartilage are united firmly to the manubrium of the sternum to provide stability to the rib cage. (Note that the sternocostal joints between the sternum and the costal cartilage of ribs 2-7 are synovial joints, thus are not synchondroses.)
Symphysis
has a pad of fibrocartilage between the articulating bones. The fibrocartilage resists both compression and tension stresses and acts as a resilient shock absorber. All symphyses are amphiarthroses.
Examples of symphysis are..
the pubic symphysis and intervertebral joints.
Pubic Symphysis
is located between the right an left pubic bones. In pregnant females, pubic symphysis becomes more mobile to allow the pelvis to change shape slightly as the fetus passes through the birth canal.
Intervertebral Joints
where the bodies of adjacent vertebrae are both separated and united by intervertebral discs. Individual intervertebral discs allow only slight movements between the adjacent vertebrae; however, the collective movements of all the intervertebral discs afford the spine considerable flexibility.
Each synovial joint is composed of a…
double-layered capsule called the articular capsule or joint capsule. Its outer layer is called the Fibrous layer and the inner Layer is a synovial membrane or synovium. The fibrous layer is formed from dense CT. It strengthens the joint to prevent the bones from being pulled apart. The synovial membrane is a specialized type of CT, the cells of which help produce and secrete synovial fluid. This membrane covers all the internal joint surfaces not covered by cartilage and lines the articular capsule.
All articulating bone surfaces in a synovial joint are covered by a…
thin layer of hyaline cartilage called Articular Cartilage; it has numerous functions: reduces friction in joint during movement, acts as a cushion to absorb compression placed on the joint, and prevents damage to the articulating ends of the bones; this specialized hyaline cartilage lacks perichondrium.
Only a synovial joint houses a…
joint cavity (or articular cavity), a space that permits separation of the articulating bones.
The articular cartilage and synovial fluid within the joint cavity reduce…
frictions as the bones move at a synovial joint.
Synovial Fluid
is a vicious, oily substance located within a synovial joint. It is a product of both the synovial membrane cells and the filtrate formed from blood plasma.
Synovial fluid has 3 functions
Lubricates (lubricates articular cartilage on the surface of articulating bones), Nourishes Chondrocytes (synovial fluid must be circulated continually to provide nutrients to and remove waste from articular cartilage’s chondrocytes), And Acts As A Shock Absorber (synovial fluid distributes stresses and force evenly across the articulating surfaces when the pressure in the joint suddenly increases).
Ligaments
are composed of dense regular CT, and they connect one bone to another bone. Ligaments function to stabilize, strengthen, and reinforce most synovial joints.
Intrinsic Ligaments
represent thickenings of the articular capsule itself; include extracapsular ligaments outside the articular capsule and intracapsular ligaments within the articular capsule.
Extrinsic Ligaments
are outside of, and physically separate from, the articular capsule.
All synovial joints have…
numerous blood vessels to transport oxygen and nutrients to the tissue, and to remove wastes. They also have sensory receptors that innervate the articular capsule and associated ligaments. These sensory receptors include proprioceptors that detect movement, stretch, and positioning of the joint.
Tendons
are like ligaments are composed of dense regular CT, but they are not part of the synovial joint itself. Whereas a ligament binds bone to bone, a tendon attaches a muscle to a bone.
Bursa
is a fibrous, saclike structure that contains synovial fluid and is lined by a synovial membrane.
there are numerous bursae in the body, and they are associated with…
most synovial joints and where bones, ligaments, muscles, skin, or tendons overlie each other and rub together.
bursae may be either…
connected to the joint cavity or completely separate from it.
bursae alleviate the…
friction resulting from the various body movements, such as where a tendon or ligament rubs against bone.
Tendon Sheath
an elongated bursa that wraps around a tendon where there may be excessive friction. Especially common in the confined spaces of the wrist and ankle.
Fat Pads
are often distributed along the periphery of a synovial joint. They act as packing material and provide some protection for the joint. Often, fat pads fill the spaces that form when bones move and the joint cavity changes shape.
Movement of a bone at a synovial joint may be described in one of 3 ways:
Uniaxial, Biaxial, and Multiaxial or Triaxial.
Uniaxial
A joint is said to be uniaxial if the bone moves in just one plane or axis.
Biaxial
A joint is biaxial if the bone move in two planes or axes.
Multiaxial or Triaxial
A joint is multiaxial or triaxial if the bone moves in multiple planes or axes.
The 6 specific types of synovial joints are
plane joints hinge joints pivot joints condylar joints saddle joints and ball-and socket joints
Plane Joint
also called a planar or gliding joint, is the simplest synovial articulation and the least mobile type of diarthrosis; a uniaxial joint because it usually allows only limited side-to-side movements in a single plane, and because there is no rotation or angular movements with this joint. The articular surfaces of the bones are flat or planar.
Examples of plane joints include…
the intercarpal and intertarsal joints (the joints between carpal bones and tarsal bones, respectively).
Hinge Joint
is formed by the convex surface of one articulating bone fitting into a concave depression on the other bone in the joint. Movement is confined to a single axis, like the movement seen at the hinge of a door; considered a uniaxial joint.
Examples of hinge joint is…
the elbow joint. The trochlear notch of the ulna fits directly into the trochlea of the humerus, so the forearm can be moved anteriorly toward the arm or posteriorly away from the arm. other hinge joints occur at the knee and the finger (interphalangeal [IP] ) joints.
Pivot joint
is a uniaxial joint in which one articulating bone with a rounded surface fits into a ring formed by a ligament and another bone. The first bone rotates on its longitudinal axis relative to the second bone.
An example of a pivot joint is..
the proximal radioulnar joints, where the rounded head of the radius pivots along the ulna and permits the radius to rotate.
Another example of a pivot joint is…
the atlantoaxial joint between the first two cervical vertebrae (i.e., the atlas and axis). The rounded dens of the axis fits snugly against an articular facet on the anterior arch of the atlas. This joint pivots when you shake your head “no”
Condylar Joint
also called condyloid or ellipsoid joints, are biaxial joints with an oval, convex surface on one bone that articulates with a concave articular surface on the second bone of the joint. Biaxial joints can move in two axes, such as back-and-forth- and side-to-side.
Examples of condylar joints
are the metacarpophalangeal (MP) joints of fingers 2-5. MP joints are commonly known as knuckles.
Saddle Joint
the articular surfaces of the bones have convex and concave regions that resemble the shape of a saddle. This biaxial joint allows a greater range of movement than either a condylar or a hinge joint.
An example of a saddle joint
is the carpometacarpal joint of the thumb (between the trapezium, which is a carpal bone, and the first metacarpal). This joint permits the thumb to move toward the other fingers so that we can grasp objects.
Ball-and-socket Joints
are multiaxial joints in which the spherical articulating head of one bone fits the rounded, cuplike socket of a second bone.
Example of ball-and-socket are the…
coxal (hip) and glenohumeral (shoulder) joints. the multiaxial nature of these joints permits movement in 3 planes. The ball-and-socket joint is considered the most freely mobile type of synovial joint.
4 Types of motion occur at synovial joints:
gliding motion, rotational motion, angular motion, and special movements.
Gliding
is a simple movement in which two opposing surfaces slide slightly back-and-forth or side-to-side with respect to one another
In a gliding motion, the angle between the bones:
does not change, and only limited movement is possible in any direction
Gliding motion typically occurs:
along plane joints, such as between the carpals or the tarsals
Angular Motion
either decreases or increases the angle between two bones; may occur at many synovial joints.
Angular motion includes what specific types?
flexion and extension, lateral flexion, abduction and adduction, and circumduction
Flexion
is movement in an anterior-posterior (AP) plane of the body that decreases the angle between the bones. Bones are brought closer together as the angle between them decreases.
Examples of Flexion:
the bending of the fingers toward the palm to make a fist, the bending of the forearm toward the arm at the elbow, flexion at the shoulder when the arm is raised anteriorly, and flexion of the neck when the head is bent anteriorly and you look down at your feet.
Extension
which is movement in an anterior-posterior (AP) plane that increases the angle between the articulating bones. Extension is a straightening action that occurs in an AP plane.
Examples of Extension:
Straightening the fingers after making a clenched fist, and straightening the forearm until it projects directly away from the anterior side of your body.
Hyperextension
is the extension of a joint beyond its normal range of motion. It may occur if someone has extensively mobile joints or an injury at the joint.
Lateral Flexion
occurs when the trunk of the body moves in a coronal plane laterally away from the body. This type of movement occurs primarily between the vertebrae in the cervical and lumbar regions of the vertebral column
Abduction
means to move away, and it is a lateral movement of a body part away from the body midline. Abduction occurs when either the arm or the thigh is moved laterally away from the body midline.
Adduction
meaning to move toward. This is the medial movement of a body part toward the body midline. Adduction occurs when the raised arm or thigh is brought back toward the body midline
Circumduction
is a sequence of movements in which the proximal end of an appendage remains relatively stationary while the distal end makes a circular motion; is a complex movement that occurs as a result of a continuous sequence of flexion, abduction, extension, and adduction.
Rotation
is a pivoting motion in which a bone turns on its own longitudinal axis; occurs at the atlantoaxial joint, which pivots when you rotate your head to gesture “no.”
Lateral Rotation
(or external rotation) turns the anterior surface of the femur or humerus laterally
Medial Rotation
(or internal rotation) turns the anterior surface of the femur or humerus medially.
Pronation
is the medial rotation of the forearm so that the palm of the hand is directed posteriorly or inferiorly.
Supination
occurs when the forearm rotates laterally so that the palm faces anteriorly or superiorly. In the anatomic position, the forearm is supinated
Special movements include
depression and elevation, dorsiflexion and plantar flexion, eversion and inversion, protraction and retraction, and opposition and reposition.
Depression
is the inferior movement of a part of the body. Examples of depression include opening your mouth (by depressing your mandible) to chew food and the movement of your shoulders in an inferior direction.
Elevation
is the superior movement of a body part. Examples of elevation include the superior movement of the mandible while closing the mouth and the movement of the shoulders in a superior direction (shrugging your shoulders)
Dorsiflexion
occurs when the talocrural (ankle) joint is bent such that the dorsum (superior surface) of the foot and the toes moves toward the leg. This movement occurs when you dig in your heels, and it prevents your toes from scraping the ground when you take a step.
Plantar Flexion
is a movement of the foot at the talocrural joint so that the toes point inferiorly. When a ballerina is standing on tiptoes, the ankle joint is in full plantar flexion.
Eversion and inversion are movements that
occur at the intertarsal joints of the foot only
Eversion
the sole of the foot turns to face laterally or outward,
Inversion
the sole of the foot turns medially or inward
Protraction
is the anterior movement of a body part from anatomic position, as when jutting your jaw anteriorly at the temporomandibular joint or hunching the shoulders anteriorly by crossing the arms.
Retraction
is the posteriorly directed movement of a body part from the anatomic position
Opposition
Movement of the thumb across the palm to touch the palmar side of the fingertips.
Reposition
The opposite movement of opposition
Lever
is an elongated, rigid object that rotates around a fixed point called the fulcrum; have the ability to alter the speed and distance of movement produced by a force, the direction of an applied force, and the force strength
Movement occurs when: an effort applied to one point on the lever exceeds a resistance located at some other point
an EFFORT applied to one point on the lever exceeds a RESISTANCE located at some other point
Effort Arm
The part of a lever from the fulcrum to the point of effort
Resistance Arm
the lever part from the fulcrum to the point of resistance
In the body, a long bone acts as
a lever, a joint serves as the fulcrum, and the effort is generated by a muscle attached to the bone.
Three classes of levers are found in the human body:
first-class, second-class, and third-class
First-Class Lever
has a fulcrum in the middle, between the effort (force) and the resistance
Example of First-class Lever
In the body, an example of a first-class lever is the atlanto-occipital joint of the neck, where the muscles on the posterior side of the neck (effort) pull inferiorly on the nuchal lines of the skull and oppose the tendency of the head (resistance) to tip anteriorly.
Second-Class Lever
is between the fulcrum and the applied effort.
Example of Second-class Lever
when the foot is plantar flexed so that a person can stand on tiptoe. The contraction of the calf muscle causes a pull superiorly by the calcaneal tendon attached to the heel (calcaneus).
Third-Class Lever
is noted when the effort is applied between the resistance and the fulcrum, as when picking up a small object with a pair of forceps; are the most common levers in the body; is found at the elbow where the fulcrum is the joint between the humerus and ulna, the effort is applied by the biceps brachii muscle at its attachment to the radius, and the resistance is provided by any weight in the hand or by the weight of the forearm itself.
Example of Third-class Lever
The mandible acts as a third-class lever when you bite with your incisors on a piece of food. The temporomandibular joint is the fulcrum, and the temporalis muscle exerts the effort, whereas the resistance is the item of food being bitten
