Anatomy Chapter 9

Synochondrosis:

(chondros=cartilage) A cartilaginous joint, an articulation in which bones are joined by hyaline cartilage. Functionally, all synochondroses are immobile and thus are classified as synarthroses. The hyaline cartilage of epiphyseal plates in children forms synochondroses that fine the epiphyses and the diaphysis of long bones, when the hyaline cartilage stops growing, bone replaces the cartilage, and synochondrosis no longer exists

Costochondral joints:

(costa=rib) they are synochondroses, the joints between each bony rib and its respective costal cartilage

Gomphosis:

(gomphos=bolt, osis=condition) resembles "peg in socket". It is a fibrous joint, the only gomphoses in the human body are the articulations of the roots of individual teeth with the sockets of the mandible and maxilla

Sutures:

(sutura=seem) are immobile fibrous joints that are found only between certain bones of the skull. Sutures have a distinct, interlocking, usually irregular edges that both increase their strength and decrease the number of fractures at these articulations. Sutures permit the skull to grow as the brain increases in size during childhood, In an older adult, the dense regular connective tissue in the suture become ossified, fusing the skull together

Syndesmoses:

(syndesmos=fastening) are fibrous joints in which articulating bones are joined by long strands of dense regular fibrous tissue only. Because syndesmoses allow for slight mobility, they are classified as amphiarthroses. Syndesmoses are found between the radius and the ulna, the fibula and the tibia

The six specific synovial joints, in order from least mobile to freely mobile:

-plane joints -hinge joints -pivot joints -condylar joints -saddle joints -ball-and-socket joints

The three functions of Synovial Fluid:

1. Synovial Fluid lubricates the articular cartilage on the articulating bones(in the same way that oil in a car engine lubricates the moving engine parts) 2. Synovial Fluid nourishes the articular cartilage's chondrocytes. The relatively small volume of synovial fluid must be circulated continually to provide nutrients and remove wastes to these cells. Whenever movement occurs a a synovial joint, the combined compression and re-expansion of the articular cartilage circulate the synovial fluid into and out of the cartilage matrix 3. Synovial Fluid acts as a shock absorber, distributing stresses and force evenly across the articular surfaces when the pressure in the joint suddenly increases

Symphysis:

A cartilaginous joint, has a pad of fibrocartilage between the articulating bones. The fibrocartilage resists compression and tension stresses and acts as a resilient shock absorber. All symphyses are amphiarthroses, meaning that they allow slight mobility

Articular disc in the acromioclavicular joint:

A fribrocartilaginous articular disc lies within the joint cavity between these two bones. This joint works with both the sternoclavicular joint and the glenohumeral joint to give the upper limb a full range of movement

Amphiarthrosis:

A slightly mobile joint(amphi=around)

Depression:

A special movement, is the inferior movement of a part of the body. EX- the movement of the mandible while opening your mouth to chew food and the movement of your shoulders in an inferior direction

Elevation:

A special movement, is the superior movement of a body part. EX- the superior movement of the mandible while closing your mouth at the tempromandibular joint and the movement of the shoulders in a superior direction(shrugging your shoulders)

Protraction:

A special movement. Is the anterior movement of a body part form anatomy position, as when moving your jaw anteriorly at the tempromandibular joint or hunching your shoulders anteriorly by crossing your arms

Retraction:

A special movement. Is the posteriorly directed movement of a body part from anatomic position

Opposition:

A special movement. It enables the hand to grasp objects and is the most distinctive digital movement in humans, the opposite movement is called reposition

Periodontal membrane:

A tooth is held in place by this fibrous periodontal membrane(peri=around, odous=tooth). This joint is functionally synarthrosis

Multiaxial(or triaxial):

A type of synovial joint, a joint is said to be multi axial if the bone moves in multiple planes or axes

Uniaxial:

A type of synovial joint, a joint is said to be uniaxial if the bone moves in just one plane or axes

Biaxial:

A type of synovial joint, a joint is said to be uniaxial if the bone moves in two planes or axes

Articular Cartilage:

All articulating bone surfaces in a synovial joint are covered by this thin layer of hyaline cartilage. This cartilage reduces friction in the joint during movement, acts as a spongy cushion to absorb compression placed on the joint, and prevents damage to the articulating ends of the bones

Intervertebral discs:

All of the vertebral bodies, between the axis, and the sacrum, are separated and cushioned by pads of fibrocartilage called intervertebral discs. Each intervertebral disc consists of two components: 1. An anulus fibrosus 2. A nucleus pulposus

Hyperextension:

An angular motion. Is the extension of a joint beyond 180 degrees

Flexion:

An angular motion. It is the movement in an anterior-posterior (AP) plane of the body that decreases the angle between the articulating bones. Bones are brought closer together as the angle between them decreases

Extenstion:

An angular motion. It is the opposite of flexion, it is a movement in an anterior-posterior plane that increases the angle between the articulating bones. Extension is a straightening action that usually occurs in the sagittal pane of the body

Lateral flexion:

An angular motion. 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

Tendon sheath:

An elongated bursa is called a tendon sheath, it wraps around tendons where there may be excessive friction. Tendon sheaths are especially common in the confine spaces of the wrist and ankle

Condylar joint(or 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. Biaxial joints can move in two aces, such as back-and-forth and side-to-side

Ligaments:

Are composed of dense regular connective tissue. Ligaments connect one bone to another and strengthen and reinforce most synovial joints

Synovial Joints:

Are freely mobile, articulations, the bones in synovial joints are separated by a space called a joint cavity. Most commonly known joints in the body are synovial joints, like the glenohumeral(shoulder) joint, the tempromandibular joint, the elbow joint, and the knee joint. Functionally, all synovial joints are classified as diarthroses, since all freely mobile the terms diarthroses and synovial joint are equated. All synovial joints have these basic features: an articular capsule, a joint cavity, synovial fluid, articular cartilage, ligaments, nerves, and blood vessels. And usually have these accessory structures: bursae, fat pads, and tendons

Ball-and-socket joint:

Are multi axial joints in which the spherical articulation head of one bone fits into the rounded, cup-like socket of a second bone

Tendons:

Are not part of the synovial joint itself. A tendon is composed of dense regular connective tissue, and it attaches a muscle to a bone. When a muscle contracts, the tendon from that muscle moves the bone to which it is attached, thus creating movement at the joint. Tendons help stabilize joints because they pass across or around a joint providing mechanical support, and can limit the range or amount of movement permitted at a joint

Fat pads:

Are often distributed alone the periphery of a synovial joint. They act as a packing material and provide some protection for the joint. Fat pads often fill the spaces that form when bones move and the joint cavity changes shape

Extrinsic ligaments:

Are outside of and physically separate from the articular capsule

Posterior Longitudinal Ligament:

Attaches the posterior aspects of the vertebral bodies and intervertebral discs. It is much thinner than the anterior longitudinal ligament, and it runs within the vertebral canal

"trade off"

Between mobility and stability for various joints, because there is an inverse relationship between mobility and stability in articulations. The more mobile a joint is, the less stable it is; and the more stable a joint is the less mobile it is

Articulate:

Bones are said to articulate with each other at a joint

Ligamentum Flavum:

Connects the laminae of adjacent vertebrae

Dorsiflexion:

Dorsiflexion is limited to the ankle. Dorsiflexion occurs when the talocrural(ankle) joint is bent such that the superior surface of the foot and toes moves toward the leg. This movement occurs when you dig your heels, and it prevents your toes from scraping the ground when you take a step

Angular motion:

Either increases or decreases 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

Interosseous membrane(or interosseous ligament):

Found in the shafts between the two articulating bones(of either the radius and the ulna or the tibia and the fibula) are bound side by side by a broad ligamentous sheet called an interosseous membrane, which provides a pivot point(where the radius and ulna or the tibia and fibula) can move against one another

The found types of motion that occur at synovial joints:

Gliding, angular, rotational, and special movements(motions that occur only at specific joints)

Synovial membrane:

In a synovial joint, the inner layer of the articular capsule

Fibrous layer:

In a synovial joint, the outer layer of the articular capsule

Articular disc in the tempromandibular joint:

In the tempromandibular joint. The articular disc is a thick pad of fibrocartilage separating the articulating bones and extending horizontally to divide the joint cavity into two separate chambers

Intervertebral Articulations:

Intervertebral Articulations occur between the bodies of vertebrae, as well as between the superior and inferior articular processes of adjacent vertebrae

Bursa:

Is a fibrous saclike structure that contains synovial fluid and is lined by a synovial membrane. Bursae are found around most synovial joints and also where bones, ligaments, muscles, skin or tendons over lied each other and rub together. They are designed to alleviate the friction resulting from the various body movements, such as a tendon or ligament rubbing against bone

Diarthrosis:

Is a freely mobile joint(di=two)

Rotation:

Is a pivoting motion in which a bone turns on its own longitudinal 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 median plane or toward it

Acromioclavicular Joint:

Is a plane joint between the acromion and the acromial end of the clavicle

Sternoclavicular Joint:

Is a saddle joint formed by the articulation between the manubrium of the sternum and the sternal end of the clavicle

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. The resulting movement makes an imaginary cone shape. Circumduction is a complex movement that occurs as a result of a continuous sequence of flexion, abduction, extension, and adduction

Gliding motion:

Is a simple movement in which two opposing surfaces slide slightly back-and-forth or side-to-side with repect 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 alone plane joints

Anterior Longitudinal Ligament:

Is a thick, sturdy ligament that attaches vertebral bodies and intervertebral discs at their anterior surfaces

Hinge 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

Stylomandibular Ligament:

Is an extracapsular ligament, is a thick band that extends from the styloid process of the temporal bone to the mandibular angle. This is a ligament that helps support the tempromandibular joint

Sphenomandibular Ligament:

Is an extracapsular ligament, is a thin band that extends anteriorly and inferiorly from the sphenoid to the medial surface of the mandibular ramus. This ligament helps support the tempromandibular joint

Synarthrosis:

Is an immobile joint(syn=joined together)

Tempromandibular Ligament(or lateral ligament):

Is composed of two short bands on the lateral portion of the articular capsule. These bands extend inferiorly and posteriorly from the articular tubercle of the mandible

Saddle joint:

Is named so because the articular surfaces of the bones have convex and concave regions that resemble the shape of the saddle. It allows greater range of movement than either a condylar or hinge joint

Tempromandibular Joint(TMJ):

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

Nucleus Pulposus:

Is the inner gelatinous core of the intervertebral discs and is primarily composed of water, with some scattered reticular elastic fibers

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

Ligamentum Nuchae:

Is the part of the supraspinous ligament that extends between C7 and the base of the skull. The ligamentum nuchae is very thick, sturdy and helps stabilize the skull on the cervical vertebrae

A Joint or Articulation:

Is the place of contact between bone and cartilage, or between bones and teeth

Plane joint(or planar or gliding joint):

Is the simplest synovial articulation and the least mobile type of diarthrosis. This type of synovial joint is also known as a uniaxial joint because only side-to-side movements are possible. The articular surfaces or the bones are flat or planar. EXs- inter carpal and inter tarsal joints(the joints between the cube-shaped carpal and tarsal bones)

Anulus Fibrosus:

Is the tough outer layer of fibrocartilage that covers each intervertebral disc. It contains collagen fibers that attach the disc to the bodies of adjacent vertebrae

Articular capsule in the tempromandibular joint:

It surrounds the joint and promotes an extensive range of motion

Interspinous Ligament:

Multiple interspinous ligaments interconnect the spinous processes of adjacent vertebrae. Their angled fibers merge with the supraspinous ligament

Inversion:

Occurs only at the intertarsal joints of the foot. In Inversion, the sole of the foot turns medially

Eversion:

Occurs only at the intertarsal joints of the foot. In eversion, the sole turns to face laterally

Supination:

Occurs when the fore am rotates laterally so that the palm faces anteriorly or superiorly, and the radius is parallel with the ulna. In anatomic position, the forearm is supinated

A Fibrous Joint:

Occurs where bones are held together by dense regular (fibrous) connective tissue. Most of them are mobile or only slightly mobile, they have no cavity(space between the articulating bones), and there are three different types of fibrous joints, gomphoses, sutures, and syndesmoses

Joint cavity(or articular cavity):

Only synovial joints house a joint cavity, it is a space that contains a small amount of synovial fluid. The cavity permits separation of the articulating bones, the articular cartilage and synovial fluid within the joint cavity reduce friction as bones move at a synovial joint

Articular disc in the sternoclavicular joint:

Partions the sternoclavicular joint into two parts and creates two separate joint cavities

Plantar flexion:

Plantar flexion is limited to the ankle, and is the movement at the talocrural joint permits the extensions of the foot so that the toes point inferiorly. When a ballerina is standing on her tiptoes, her ankle joint is in full plantar flexion

Intrinsic ligaments:

Represent thickenings of the articular capsule itself, they include extracapsular ligaments, which are outside the articular capsule and intracapsular ligaments, which are within the articular capsule

Special Movements:

Some motions occur only at specific joints and do not readily fit into any of the functional categories previously discussed. These special movements include depression and elevation, protraction and retraction, and opposition

Cartilaginous Joints:

The articulating bones in cartilaginous joints are attached to each other by cartilage, these joints lack a cavity. The two types of cartilaginous joints are synchondrosis and symphyses

Synovial fluid:

The lining of the joint cavity is the synovial membrane, which secretes a viscous, oily synovial fluid. It is composed of secretions from synovial membrane cells and filtrate from blood plasma

Adduction:

The opposite of abduciton. Adductions means to "move toward", and is the medial movement of a body part toward the midline. Adduction occurs when you bring you bring your raised arm or thigh back toward the midline, or in the case of digits, toward the midline of the hand. Adducting the wrist(also known as ulnar deviation) involved pointing the hand and fingers medially, toward the body

Arthology:

The scientific study of joints

Articular capsule:

This is a double-layered capsule, and each synovial joint is composed of this

Supraspinous Ligament:

This ligament interconnects the tips of the spinous processes from C7 to the sacrum

Later 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

Synostoses:

When the bones in your skull have completely fused across the suture line, the obliterated sutures become synostoses

Abduciton:

Which means to "move away", is the lateral movement of a body part away from the body midline. Abductions occurs when either the arm or the thigh is moved laterally away from the midline. Abduction of either the fingers or the toes meanest hat you spread them apart, away from the loges digit, which is acting as the midline Abduciting the wrist(also known as radial deviation) involved pointing the hand and fingers laterally, away from the body