Study Guide + Quizzes: 9 - Joints and Articulations

What is a joint/articulation?

site where two bones come together

Functional Classification of Joints

functional: based on the amount of movement allowed

1. synarthroses: immobile joints

   1. sutures of skull

2. amphiarthroses: slightly moveable

   1. intervertebral discs between vertebrae

3. diarthroses: freely moveable joints

   1. joints of appendicular skeleton (all synovial joints - hip, elbow, etc.)

Structural Classification of Joints

structural: based on material, which joins bones

1. fibrous joints: joints composed of fibrous tissue, no joint cavity present

   1. sutures: short fibrous fibers, found in skull, immovable

   2. syndesmosis: cord of fibrous tissue (ligament); amphiarthrosis with “give” but no actual movement

      1. ex: distal tibiofibular joint

   3. gomphosis: tooth within its bony socket; short ligament

2. cartilaginous joints: joints composed of cartilage, no joint cavity

   1. synchondrosis: plate of hyaline cartilage; sites of bone growth during youth; eventually ossify = synarthrotic

      1. ex: joint between first rib and manubrium; epiphyseal plate

   2. symphysis: pad or plate of fibrocartilage; compressible “shock absorber”; limited movement = amphiarthroses

      1. ex: intervertebral discs, pubis symphysis

3. synovial joints: fluid-filled joint cavity; freely movable = diarthrosis

General Structure of a Synovial Joint

there are 5 distinct features of a synovial joint

1. articular cartilage: hyaline cartilage covers the surface of each bone

2. joint cavity: a potential space between the two bones, filled with synovial fluid

3. articular capsule: double layered capsule surrounding cavity

   1. external, tough flexible fibrous capsule

4. synovial membrane: loose CT lining of fibrous capsule, also covers all internal joint surfaces excluding hyaline cartilage

5. synovial fluid: lubricating fluid within cavity; reduces friction between bones, provides “weeping lubrication” nourishes cartilage, contains phagocytes

6. reinforcing ligaments: ligaments that strengthen joint

   1. ligament: joins bone to bone

7. extra features:

   1. fatty pads: hip and knee

   2. menisci or articular discs: separate cavity into 2 compartments

   3. bursa: flattened sacs with synovial membrane + fluid inside = prevent friction, cushion. it is located between skin and bone, muscles, tendons, and ligaments

Types of Synovial Joints

• ball and socket joints: most freely movable joints, all angular movement, the head of one bone fits into socket of another

  • ex: hip and shoulder

• condyloid joints: permit all angular motion, except rotation

  • ex: wrists and knuckles

• gliding joints: cartilaginous joints, flat bones glide/slide over on another

  • ex: intervertebral discs

• hinge joints: permit flexion and extension only

  • ex: elbow and knee

• pivot joints: permit rotation

  • ex: first intervertebral joint (atlantoaxial joint)

• saddle joints: thumb

Types of Joint Movements

• flexion: decreasing angle between 2 bones

• extension: increasing angle between 2 bones

• dorsiflexion: bringing foot closer to shin, rolling back on heel

• plantar flexion: pointing one’s toe, tippy toes

• hyperextension: increasing angle greater than normal (180 degrees)

• abduction: moving limb AWAY from midline (raising arm)

• adduction: moving a limb back towards midline

• circumduction: moving limb in circular (cone-shaped) manner

• rotation: turning movement of a bone along axis (atlas over axis, shoulder/hip)

• supination/pronation: movements between radius and ulna at radioulnar joint (palm up = supination, palm down = pronation)

• inversion/eversion: movement of foot (sole inward = inversion, sole out = eversion)

• elevation/depression: moving up or down (shoulder shrug = elevation, opening mouth = depression)

• protraction/retraction: going forward or back (thrust forward = protraction, pull back = retraction)

Concept Map

Match the joints to their locations

• synarthroses: sutures of skull, gomphoses of teeth

• amphiarthroses: intervertebral disc and pubic symphysis

• diarthroses: finger joints, ankle and wrist joints

• multiaxial synovial joint: shoulder

• biaxial synovial joint: metacarpal, phalangeal joints

• uniaxial synovial joint: elbow

cartilaginous joints (3 answers):

1. lack a synovial cavity

2. have a synovial cavity

3. articulating bones are held together with cartilage connective tissue

4. permit little or no movement

5. permits gliding movement

1, 3, and 4

• lack a synovial cavity

• articulating bones are held together with cartilage connective tissue

• permit little or no movement

fibrous joints (3 answers):

1. Lack a synovial cavity

2. Have a synovial cavity

3. Articulating bones are held together by dense irregular connective tissue

4. Permitted movement is free and unrestricted

5. Permit little or no movement

6. Permit rotation around a central axis

1, 3, and 5 are correct

• lack a synovial cavity

• articulating bones are held together by dense irregular connective tissue

• permit little or no movement

Which of the following are specific structural types of fibrous joints? (Select 3 answers)

• Sutures

• Syndesmoses

• Synchondroses

• Symphyses

• Interosseous membranes

• Planar joints

Sutures, syndesmoses, and interosseous membranes

synovial joints (Select 3 answers)

1. Lack a synovial cavity

2. Have a synovial cavity

3. Articulating bones are covered by a layer of hyaline cartilage called articular cartilage

4. Provide a range of motion from slightly movable to freely movable

5. Permit no movement whatsoever

6. Bones are bound exclusively by a solid sheet of fibrocartilage

2, 3, and 4 are correct

• have a synovial cavity

• articulating bones are covered by a layer of hyaline cartilage called articular cartilage

• provide a range of motion from slightly moveable to freely movable

Which of the following are functional or structural components found in synovial joints? (Select 3 answers)

• Articular capsule

• Synovial fluid

• Periodontal ligament

• Sutural ligament

• Accessory ligaments (such as extracapsular and intracapsular ligaments)

• Epiphyseal cartilage plate

• articular capsule

• synovial fluid

• accessory ligaments

All of the following are freely moving joints, EXCEPT______

1. gomphosis

2. hinge

3. ball and socket

4. sutures

5. pivot

1. gomphosis

4. sutures

Match the following terms with their functions and/or definitions.

Match the following terms with their functions and/or definitions.

1. flexor: The muscle that closes the joint

2. extensor: The muscle that opens the joint

3. orbicularis: round

4. trapezius: triangular

5. deltoid: Greek letter delta

6. pectoralis: chest /breast

7. origin: a bone that remains immobile for an action

8. insertion: bone that moves during the action

flexion ________, adduction _________

1. Decreases the size of the angle; moves the arm or leg towards the body

2. Decreases the size of the angle; moves the arm or leg away from the body

3. Increases the size of the angle; moves the arm or leg towards the body

4. Increases the size of the angle; moves the arm or leg away from the body

1. Decreases the size of the angle; moves the arm or leg towards the body

Muscle nomenclature is based on ____________

1. location of origin and insertion

2. direction of muscle fibers

3. appearance

4. Muscle action

5. muscle shape

6. Number of origins

1. location of origin and insertion

2. direction of muscle fibers

3. appearance

4. Muscle action

5. muscle shape

6. Number of origins