Skeletal System: Articulations

What is the function of the bursa?

They serve to alleviate the friction resulting from the various body movements, such as where tendons or ligaments rub against bone.

What is the structure of a synthesis? What is it resistant to? What is its functional characteristics?

A symphysis has a pad of fibrocartilage between articulating bones. The fibrocartilage resist both compression and tension stresses and acts as a resilient shock absorber. All symphysis are amphiarthrosis - thus they allow slight mobility.

What is a joint cavity?

Also known as the articular cavity, a space that permits the separation of the articulating bones.

What is synchondrosis? How is it functionally classified?

An articulation in which bones are joined by hyaline cartilage. Functionally, all synchondrosis are immobile and thus are classified functionally as synarthrosis.

The scientific study of joints is called ________.

Arthology

Why is the repetitious compression and expansion that occurs during exercise vital to maintaining healthy articular cartilage?

Because this action enhances the articular cartilages ability to obtain nutrition and in its waste removal.

Only synovial joints house a joint ________.

Cavity

What is the structure of a synovial joint? What is the composition of an articular capsule? What is the function of the fibrous layer of the joint capsule? What is the function and structure of the synovial membrane?

Each synovial joint is composed of a double layered capsule called and articular capsule. Its outer layer is called fibrous layer, and the inner layer is a synovial membrane. The previous layer is formed from dense connective tissue. It strengthens the joint to prevent the Bones from being pulled apart. The synovial membrane is composed of squamous epithelial cells- that lack a basement membrane - resting on an areolar connective tissue layer. This membrane covers all the internal joint surfaces not covered by cartilage and lines the articular capsule, and helps produce synovial fluid.

What is the location of extrinsic ligaments? What do intrinsic ligaments represent?

Extrinsic ligaments are outside of, and physically separate from the joint capsule, where is intrinsic ligaments represent thickening of the articular capsule itself. Intrinsic ligaments include extracapsular ligaments outside the Joint capsule and intracapsular ligaments within the joint capsule.

What is the location and function of fat pads?

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 will fill the spaces that form when bones move than the joint cavity changes shape.

What are the three most common types of fibrous joints?

Gomphosis, sutures, and syndesmosis.

What is an example of the lever system in the body?

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.

What are the several basic features of a synovial joint?

It includes an articular capsule, a joint cavity, synovial fluid, articular cartilage, ligaments, nerves, and blood vessels.

What is the function of a lever?

Levers have the ability to alter or change the speed and distance of movement produced by a force, the direction of an applied force, and the force strength.

How is movement produced at a lever?

Movement occurs when an effort applied to one point on the lever exceeds a resistance located at some other point.

What types of individuals are most likely seen of having a TMJ disorder?

People who habitually chew gum or grind or clench their teeth.

What does gomphosis resemble?

Resembles a peg in a socket.

What is rotational motion? What are examples of rotational motion?

Rotation is a pivoting motion in which a bone turns on its own longtitudinal axis. Rotational movement occurs at the atlantoaxial joint, which pivots when you rotate your head to gesture "no".Some limb rotations are described as either away from the medial plane or toward it. For example, lateral rotation - or external rotation - turns the anterior surface of the femur humerus laterally, whereas medial rotation turns the anterior surface of the femur humerus immediately. Pronation is the medial rotation of the forearm so that the palm of the hand is directed posteriorly or inferiorly. The radius and ulna are crossed to form an X. Supination occurs when the forearm rotates laterraly so that the palm faces anteriorly or superiorly. In the anatomic position, the forearm is supinated.

What are the similarities and differences between tendons and ligaments?

Tendons and ligaments are composed of dense regular connective tissue, 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.

What is the function of the joint cavity?

The articular cartilage and synovial fluid within the joint cavity together reduce friction as bones move at a synovial joint.

What is the most common TMJ disorder and what is it a result of? What are the signs and symptoms? Why is the pain so widespread across the face?

The most common TMJ disorder occurs as a result of alterations in the ligaments that secure the joint, causing progressive internal displacement of the articular disc. As the articular disc is forced out of its normal position, a clicking or popping noise may be heard as the person opens or closes the mouth. Pain from the TMJ disorder may be felt not only within the join but also in such areas as the paranasal sinuses, tympanic membrane - eardrum -, oral cavity, eyes, and teeth. The widespread distribution of pain occurs because all of these structures, including the muscle in jaws, are innervated by numerous sensory branches of the trigeminal nerve.

What is the structure of a second class lever? What are examples of a second class lever?

The resistance in a second class lever is between the fulcrum and the applied effort. A common example of this type of lever is tilting the handles of a wheelbarrow, allowing it to pivot on its wheel at the opposite and and lift a load in the middle. The load weight is the resistance and the upward lift on the handle is the effort. A small force can balance the larger weight in this type of lever, because the effort is always farther from the fulcrum than the resistance. Second class levers are rare and the body, but one example occurs when the foot is depressed - plantar flexed - so that a person can stand on tiptoe. The contraction of the calf muscles causes a pull superiorly to the calcaneal tendon attached to the heel -calcaneus.

What are the different types of movements that are allowed at the temporomandibular joint?

The temporomandibular Joint exhibits hinge, gliding, and some pivot joint movements. It functions like a hinge during jaw depression and elevation while chewing. It glides slightly forward during protraction of the jaw for biting, and glide slightly from side to side to grind food between the teeth during chewing.

How are synovial joints different from the previously discussed joints? What is their functional characteristic?

Unlike the joints previously discussed, the bones in a synovial joint are separated by space called a joint cavity. Functionally, all synovial joints are classified as diarthrosis, because all are freely mobile.

What is a condylar joint? And what perpendicular plane does it act upon? What are examples of a condylar joint?

1. A condylar joint, also called condyloid or ellipsoid joints, are an oval, convex surface of one bone that articulates with a concave articulating surface on the second bone of the joint. 2. It is a biaxial joint, such as back and forth and side to side. 3. Examples of a condylar joint are the metacarpalphalangeal joints of Fingers 2 through 5. The MP joints are commonly referred to as knuckles.

What is a plane joint? In what perpendicular plane does it act upon? What are the articular surfaces of the bones? What are examples of plane joints?

1. A plane joint, also called a planner or gliding joint, is the simplest synovial articulation and the least mobile type of diarthrosis. 2. We describe this type of synovial joint as uniaxial because it usually allows limited side-to-side movements in the single plane, and so there's no rotational or angular movement with this joint. 3. The articulating surfaces of the bones are flat, or planar. 4. Examples of plane joints include the intercarpal and intertarsal Joints - the joints between the carpal bones and tarsal bones.

What are the articulating surfaces of a saddle joint? In what perpendicular plane does it act upon? What are examples of a saddle joint?

1. A saddle joint is so named because the articulating surfaces of the bones have convex and concave regions that resemble the shape of a saddle. 2. This biaxial joint allows a greater range of movement than either a condylar or hinge joint. 3. The carpometacarpal Joint of the thumb - between the trapezium and the first metacarpal - is an example of a saddle joint. This joint permit the thumb to move toward the other fingers so that we can grasp objects.

What is Synarthrosis? Amphiarthrosis? Diarthroses?

1. A synarthrosis is an immovable joint. Two types of fibrous joints and one type of cartilaginous joints are synarthrosis. 2. An amphiarthrosis is a slightly mobile joint. One type of fibrous joints and one type of cartilaginous joint are amphiarthrosis. 3. A diarthrosis is a freely mobile joint. All synovial joints are diarthrosis.

What are the functions of articular cartilage?

1. Articular cartilage has numerous functions: it reduces friction in the joints during movement. 2. Acts as a spongy cushion to absorb compression placed on the joint. 3. And prevents damage to the articulating ends of the bones.

What is the perpendicular axis in which a ball-and-socket joint acts upon? What is the articulating surface of a ball-and-socket joint? What are examples of a ball-and-socket joint?

1. Ball and socket joints are multiaxial joints in which the spherical articulating head of one bone fits into the rounded, cup like socket of a second bone. 3. Examples of these joints are the coxal - hip - and glenohumeral - shoulder - joints.

How is a hinge joint formed? What perpendicular axes does it act upon? What are examples of a hinge joint?

1. By the convex surface of one articulating bone filling into a concave depression on the other bone in the joint. 2. Movement is confined to a single axis, like the movement seen at the hinge of the door, so a hinge joint is considered a uniaxial joint. 3. Examples include the elbow joint, the trochlear notch of the ulna fits directly into the trochlea of the humerus, so the formarm can be moved only anteriorly toward the arm or posteriorly away from the arm. Other hinge joints occur in the knee and the finger joints.

What is the structure and function of ligaments?

1. Ligaments are composed of dense regular connective tissue, and they connect one bone to another bone. 2. Ligaments function to stabilize, strengthen, and reinforce most synovial joints.

All synovial joints have numerous ________ and _________ that innervate and supply the articular capsule and associated ligaments.

1. Sensory nerves 2. Blood vessels

What joints are associated with movement at the shoulder?

1. Sternoclavicular 2. Acromioclavicular 3. Glenohumeral

What is the structure and location of synovial fluid? How is it produced?

1. Synovial fluid is a viscous, oily substance located within a synovial membrane. 2. It is produced both from the synovial membrane cells and filtrate formed from blood plasma.

What are the three intersecting perpendicular planes or axes?

1. The joint is said to be uniaxial if the bone moves in just one plane or axis. 2. A joint is biaxial if the bone moves in two planes or axis. 3. A joint is multiaxial - or tri-axial - if the bone moves in multiple planes or axes.

What is the temporal mandibular joint? What is unique about it?

1. The temporomandibular joint is the articulation formed at the point where the head of the mandible articulates with the temporal bone, specifically the articular tubercle of the temporal bone anteriorly and the mandibular fossa posteriorly. 2. This small, complex articulation is the only mobile joint between two bones in the skull.

What is the function of tendons?

1. When a muscle contracts, the tendon from that muscle moves the bone to which it is attached, thus causing movement at the joint. 2. Tendons help stabilize joints because they pass across or around a joint to provide mechanical support, and sometimes they limit the range amount of movement permitted at a joint.

What is a pivot joint? And what perpendicular plane does it act upon? What are examples of a pivot joint?

1. When one articulating bone with a rounded surface fits into a ring formed by a ligament and another bone. 2. it is a uniaxial joint. 3. The first bone rotates on its longitudinal axis related to the second bone. 4. Example is the proximal radial - ulnar joint, where the rounded head of the radius pivots along the ulna and permits the radius to rotate. Another example is the atlanto - axial joint between the first two cervical vertebra. The rounded dens of the axis fits snugly against and articular facet on the anterior arch of the atlas. This joint papers when you shake your head "no".

What are the four types of motions that occur at synovial joints?

1. gliding 2. angular 3. rotational 4. special movements - motions that occur only in specific joints

From least mobile to most freely mobile, name the six specific types of synovial joints?

1. plane joints 2. hinge joints 3. pivot joints 4. condylar joints 5. saddle joints 6. ball-and-socket joints

What are the functions of synovial fluid?

1. synovial fluid lubricates the articular cartilage on the surface of articulating bones - in the same way that oil in a car engine lubricates the moving engine parts. 2. Synovial fluid nourishes the articular cartilages chondrocytes. The relatively small volume of synovial fluid must be circulated continually to provide nutrients and to remove waste from the cells. Whenever movement occurs at a synovial joint, the combined compression and re-expansion of the articular cartilage circulates the synovial fluid into and out of the cartilage. 3. Synovial fluid acts as a shock absorber, distributing stresses and forces evenly across the articular surfaces when the pressure and the joint suddenly increases.

The sternal costal joints between the sternum and the costal cartilage of ribs ________ are __________ and not synchondrosis.

2-7 Synovial joints

What is the structure of a bursa?

A bursa is a fibrous, sac-like structure that contains synovial fluid and is lined internally by a synovial membrane.

What is the structure and location of a cartilaginous joint?

A cartilaginous joint has no joint cavity and occurs where bones are joined by cartilage.

What is the structure of a fibrous joint and what is its location?

A fibrous joint has no joint cavity and occurs where bones are held together by dense regular connective tissue.

What is the structure of a first class lever? What are examples of a first class lever?

A first class lever has a fulcrum in the middle, between the effort - force - and the resistance. An example of first class lever is a pair of scissors. The effort is applied to the handle of the scissors while the resistance is at the cutting and of the scissors. The fulcrum - pivot for movement - is along the middle of the scissors, between the handle and the cutting ends. In the body, an example of a first class lever is the atlantoaxial 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.

What is the structure of the synovial joint?

A synovial joint has a fluid-filled joint cavity that separates the articulating surfaces of the bones. Articulating surfaces are enclosed within a connective tissue capsule, and the bones are attached to each other by various ligaments.

What is the structure of a third class lever? Where are they most common? What is an example of a third class lever?

A 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. third class levers are the most common levers in the body. A third class lever is found at the elbow where the fulcrum is the joint between the humerus and the ulna, the effort is applied by the biceps brachii muscles, and the resistance provided by any weight in the hand or by the weight of the forarm itself. 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, the temporalis muscle exert the effort, where is the resistance is the item of food being bitten.

What is angular motion? What are the specific types of angular motion? What are examples of joints that exhibit angular motion?

Angular motion either decreases or increases the angle between two bones. These movements may occur at many of the synovial joints. They include the following specific types: flexion and extension, hyperextension, lateral flexion, abduction and adduction, and circumduction.

Articulating bone surfaces in a synovial joint are covered by a thin layer of hyaline cartilage called _________ _________.

Articular Cartilage

What is the location of the bursa?

Bursa are associated with most synovial joints and are where bones, ligaments, muscles, skin, or tendons overlie each other and rub together. They may either be connected to the joint cavity or completely separate from it.

How is the nervous system able to detect changes in our posture and adjust body movements?

By monitoring stretching at a joint, the sensory nerves detect painful stimuli in the joint and report on the amount of movement and stretch within the joint.

What is the structure of cartilaginous joints? How are they similar to fibrous joints? What is their functional classification? what type of cartilage can be found in between the articulating bones? What are the two types of cartilaginous joints?

Cartilaginous joints have cartilage between articulating bone. Like fibrous joints, cartilaginous joints also lack a joint cavity. They may be either a mobile or slightly mobile. The cartilage found between articulating bones is either hyaline cartilage or fibrocartilage. The two types of cartilaginous joints are synchondrosis and symphyses.

What is costochondritis? Where is it usually localized? What is the cause of costochondritis? What may the chest pain be mistaken for? How can costochondritis be treated? How long does it take for the symptoms to typically disappear?

Costochondritis refers to the inflammation and irritation of the costochondral joints, resulting in localized chest pain. The cause of costochondritis is usually unknown, but some documented cases include repeated minor trauma to the chest wall - from forceful repeated coughing or from overexertion during exercise - or either bacterial or viral infection of the joints themselves. The localized chest pain may be mistaken for pain resulting from a Myocardial infarction - heart attack -. Costochondritis may be treated with NSAIDs - non steroidal anti-inflammatory drugs, such as aspirin. With proper rest and treatment, symptoms typically disappear after several weeks.

What is the movement of gliding? How much movement does it allow? Where does it occurs in? What is an example?

Is a simple movement in which two opposing surfaces glide 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. Glidding motion typically occurs along plane joints, such as between the carpals or the tarsals.

What is a joint, articulation?

It is a place of contact between bones, between bone and cartilage, or between bones and teeth.

What is the structure and location of a tendon sheath?

It is an elongated bursa that wraps around a tendon where they may be excessive friction. Tendon sheets are especially common in the confined spaces of the wrist and ankle.

What is a lever?

It is an elongated, riggid object that rotates around a fixed point called a fulcrum.

What is the effort arm?

It is the part of a lever from the fulcrum to the point of effort.

What is the resistance arm?

It is the part of the lever from the fulcrum to the point of resistance.

What is it that articular cartilage lacks?

It lacks a perichondrium.

How are joints classified? How are the joints categorized structurally?

Joints are classified by both their structural characteristics and the movement they allow. Joints are categorized structurally on the basis of whether a space occurs between articulating bones and the type of connective tissue that binds articulating surfaces of the bones.

What is an example of a synthesis regarding the pelvis? What is its location? What is its function during pregnancy?

One example of a synthesis is the pubic symphysis, which is located between the right and left pubic bones. And pregnant females the pubic symphysis becomes more mobile to allow the pelvis to change shape slightly as the fetus passes through the birth canal.

What is an example of a synthesis regarding the vertebra?

One example of symphysis are the intervertebral joints, where the bodies of adjacent vertebrae are both separated and united by the intervertebral discs. Individual vertebral discs allow only for slight movements between the adjacent vertebrae; however, the collective movements of all the intervertebral discs of the spine afford considerable flexibility.

What ligaments support the TMG? What is the structure of the ligaments and location?

Several ligaments support the TMJ. The sphenomandibular joint-extracapsular ligaments - is a thin band that extends anteriorly and inferiorly from the sphenoid to the medial surface of the mandibular ramus. The temporomandibular ligament - or lateral ligament - is composed of two short bands that extend inferiorly and posteriorly from the articular tubercle the temporal bone to the mandible.

What fibers and ligaments gives support and stability to the sternoclavicular Joint?

Support and stability are provided to the circulation by the fibers of the articular capsule and by multiple extracapsular ligaments, such as a sternoclavicular and costo clavicular ligaments. This anatomical arrangement makes the sternoclavicular joint very stable. If you fall on an outstretched hand so the force is applied to the Joint, the clavicle will fracture, before this joint dislocates.

What is a structure and function and location of sutures?

Sutures are immobile fibrous joints that are found only between certain bones of the skull. Sutures have distinct interlocking irregular edges that both increase their strength and decrease in number of fractures at these articulations. In addition to joining bones, sutures permit the skull to grow as the brain increases in size during a childhood. In an older adult, the dense regular connective tissue in the suture becomes ossified, fusing the skull bones together. When the Bones have completely fused across the suture line these obliterated sutures become synostosis.

What is a structure, function, location of syndesmosis? What is the name of the broad ligament sheet that helps bind the shafts of the two articulating bones? What is it functionally classified as?

Syndesmosis are fibrous joints in which articulating bones are joined by long strands of dense regular connective tissue only. Because syndesmosis allows for slight mobility, they are classified functionally as amphiarthrosis. Syndesmosis are found both between the radius and ulna and between the tibia and fibula. The shaft of the two articulating bones are bound by a broad ligamentous sheet called an interosseous membrane. The interosseous membrane provides a pivot where the radius and ulna of the tibia and fibula can move against one another.

How are synovial joints classified by?

Synovial joints are classified by the shapes of their articulating surfaces and in the types of movement they allow.

What are synovial joints? What are some examples of synovial joints?

Synovial joints are freely mobile articulations. Most of the commonly known joints in the body are synovial joints, including the glenohumeral joint, The temporomandibular Joint, the elbow joint and the knee joint.

What is the location of gomphosis? What is an example? How is it functionally categorized?

The only gomphosis in the human body are the articulations of the roots of individual teeth with the alveolar processes of the mandible and the maxillae. A tooth is held firmly in place by periodontal membranes. This joint is functionally classified as a synarthrosis.

How do braces work to reposition the teeth?

The orthodontist job is to reposition what is normally a immobile joint through the use of clamps, bands, rings, and braces. In response to these mechanical stressors, osteoblast and osteoclast work together to modify by the alveolar process, resulting in the remodeling of the joints an the slow repositioning of the teeth.

What is biomechanics?

The practice of applying mechanical principles to biology. Such as when analyzing synovial joint movement and muscle contraction, anatomist often compare the movement to the mechanics of a lever.

What is the location of the speno - occipital synchondrosis? When does it typically fuse? What makes it a useful tool?

The speno - occipital synchondrosis is typically found between the body of the sphenoid and the basilar part of the occipital bone. This synchondrosis typically fused between 18 and 25 years of age , making it a useful tool for assessing the age of the skull.

What is the anatomical structure of the sternoclavicular joint? What are the different movements allowed at the SC joint?

The sternoclavicular joint of a saddle joint formed by the articulation between the manubrium of the sternum and the sternal end of the clavicle. An articular disc partitions the sternoclavicular joint into two parts and forms two separate synovial cavity. The result, a wide variety of movements are possible, including depression, elevation, and circumduction.

What is the structure of the temporomandibular joint? What are its anatomical features?

The temporomandibular Joint has several unique and anatomic features. A loose articular capsule surrounds a joint and promotes an extensive range of motion. It contains an articular disc that is a thick pad of fibrocartilage separating the articulating bones and extending horizontally to divide the synovial cavity into two separate chambers. As a result, the TMG is ready two synovial joints - one between the temporal bone and the articular disc and a second between the articular disc and the mandible.

What is an example of a synchondrosis that occurs in children?

styling cartilage of epiphyseal plates in children form synchondrosis that find epiphysis and diaphysis of long bones. When hyaline cartilage stops growing, bone replaces the college and a synchondrosis no longer exist.