A&P1 Chapter8

articuations

functional connections between bones

230

__ joints in the average adult

joints

__ are classified by the types of tissues that bind the bones at the junctions and by the degree of movement possible

synarthrotic

immovable (sutures)

amphiarthrotic

slightly moveable (between vertebrae)

diarthrotic

freely movable (elbow, knee)

fibrous joints

__ are held together with dense connective tissue

Typically, no movement (synarthrotic)

Found in bone in close contact

syndesmoses fibrous joints

are bones that are held together by a sheet (intermembranous membrane) or bundle (interosseous ligament) of dense connective tissue (Amphiarthrotic)

Between the tibia and fibula at the distal ends, and between the diaphysis

fibrous joint

syndesmoses are the only amphiarthrotic __

suture fibrous joints

are a thin layer of connective tissue (suture ligament) that connects bones and is located between the flat bones of the skull  (synarthrotic)

gomphosis fibrous joints

is a cone-shaped bony process in a socket (Synarthrotic) found in the gums

Root of a tooth in the maxilla or mandible held in place by periodontal ligament

NO

is a tooth a bone?

cartilaginous joints

__ are connected by hyaline cartilage or fibrocartilage 

synchondroses

have bands of hyaline cartilage that unite bones (Synarthrotic)

Some are temporary, such as the epiphyseal plate (ossification converts this to a synostosis = fusing of the bone and plate)

Some are permanent, such as between the manubrium and the first rib (costal cartilages)

symphysis

__ has fibrocartilage, connecting bones and articular surfaces covered by hyaline cartilage (Amphiarthrotic), undergoing birth, these will adjust!

synovial joints

Most joints are __, and ALL are diarthrotic joints → freely moveable

Have a more complex structure than fibrous or cartilaginous joints

Articular cartilage covers the articular ends of bones

articular cartilage

covers articular ends and resists wear and minimizes friction. Spongy bones also help with shock absorption

joint capsule

2 layers to hold bones together and surround joints

ligaments

reinforce the joint capsule and bind the articular ends

synovial membrane

only a few cells thick and is loose connective tissue

synovial cavity

closed sac surrounded by synovial membrane

synovial fluid

clear, viscous fluid; moistens and lubricates; supplies nutrients; contains stem cells

meniscus (in some joints)

discs of fibrocartilage; the meniscus attaches to the fibrous layer of the joint capsule peripherally, and its free surface is into the joint cavity

bursa (in some joints)

fluid-filled sacs; between the tendons and bony prominences; suprapatellar bursa; infrapatellar bursa; prepatellar bursa

types of synovial joints

• Ball-and-socket, also called a spheroidal joint

• Condylar joint or ellipsodial joint

• Gliding joint

• Hinge joint

• Pivot joint or trochoid joint

• Saddl joint or sellar joint

• Examples = jaw, shoulder, elbow, hip, knee

ball-and-socket joint (spheroidal joint)

Round head in a cup-shaped cavity

Widest range of motion

Multiaxial, plus rotation

(Hip and Shoulder)

conylar joint (ellipsoidal joint)

Oval condyle fits into elliptical cavity

Back-and-forth, side-to-side movement

Biaxial movement, no rotation

(Joints between Metacarpals and Phallanges)

gliding joint (plane joint)

Almost flat, or slightly curved

Back-and-forth and twisting

Nonaxial movement

(Wrist and ankle joints)

hinge joints

A convex surface fits into the concave surface of another bone

Uniaxial movement (in 1 plane)

(elbow, joints between phalanges)

pivot joint (trochoid joint)

The cylindrical surface rotates within a ring of other bone

Uniaxial movement

Rotation only

(altas C1; dense of axis C2)

saddle joint (sellar joint)

Both bones have concave and convex surfaces

Biaxial movement (in 2 planes)

(carpal and metacarpal of the thumb)

skeletal muscle

The action of __ moves synovial joints

origin

= relatively fixed end of skeletal muscle

insertion

= the more movable end of a skeletal muscle

origin

Movement at a joint occurs when a muscle contracts, and its fibers pull the insertion toward the __

flexion

__ = bending of parts at a joint

extension

= straightening of parts at a joint

hyperextension

= extension beyond the normal anatomical position

lateral flexion

= bending to the side

abduction

= moving a part of the body away from the midline

adduction

__ = moving a part of the body toward the midline

dorsiflexion

= ankle movement that points toes upward

plantar flexion

__ = ankle movement that points toes downward

circumduction

__ = movement of a part of the body in a circular path

rotation

__ = moving a part of the body around an axis

medial rotation

__ = movement of the limb; anterior surface moves toward the midline

lateral rotation

__= movement of the limb; anterior surface moves away from the midline

supination

__ = forearm rotation so the palm faces upward or forward, or lying down face up (supine)

pronation

__ = forearm rotation, so the palm faces downward or backward, or lying down face down (prone)

inversion

__ = turning of the foot so the plantar surface faces midline

eversion

__ = turning of the foot so the plantar surface faces away from the midline

protaction

__= movement of a body part forward

retraction

__ = movement of a body part backward

elevation

__ = raising a body part

depression

__ = lowering a body part

Jaw

Modified hinge joint between the mandibular condyle of the mandible and the mandibular fossa of the temporal bone

articular disc

= consisting of fibrocartilage, separates the synovial cavity into 2 portions

mandible (jaw)

The only movable joint in the skull

jaw

Movements in the  __ include elevation and depression of the mandible for chewing, slight gliding (forward and side-to-side) movements for biting and grinding food

hinge joint

Hinge Joint = between the trochlea of the humerus and the trochlear notch of the ulna (flexion/extension only)

Plane (gliding) Joint

= between the capitulum of the humerus and the fovea on the head of the radius (pronation/supination; several reinforcing ligaments)