Anatomy & Physiology 1 Exam 2 Notes
Chapter 8 – Joints:
Joints = Articulations:
-Articulation = site where two or more bones meet
- Functions of joints are to:
1.Give skeletal mobility
2. Hold skeleton together
- Two classifications of joints:
1.Functional
2. Structural
Functional Classification of Joints:
-Based on amount of movement joint allows
- 3 Functional Classifications:
1.Synarthroses immovable joints; ex: sutures; mainly axial skeleton
2. Amphiarthroses slightly movable joints; ex: pubic synthesis; mainly axial skeleton
3. Diarthroses freely movable joints; ex: most joints in limbs; mainly appendicular
skeleton
Structural Classification of Joints:
-Based on material binding bones together, and the presence/absence of a joint cavity
- 3 Structural Classifications:
1.Fibrous Joints
2. Cartilaginous Joints
3. Synovial Joints
Fibrous Joints:
-Fibrous joints = bones joined by dense fibrous connective tissue
- No joint cavity
- Most are synarthrotic (immovable)
- 3 types of fibrous joints:
1.Sutures seam; rigid, interlocking joints; immovable joints for protection of brain;
made of short connective tissue fibers, which allow for growth during youth; in middle age, the
fibers ossify and fuse (called synotoses)
2. Syndesmoses bones connected by ligaments (bands of fibrous tissue); fiber length
varies, so movement varies; ex: where tibia and fibula come together (tibiofibular joint); fibrous
tissue varies in length, but is always longer than sutures; more movable than sutures; large
amount of movement at interosseous membrane connecting radius and ulna
3. Gomphoses ped-in-socket joints of teeth in alveolar sockets; fibrous connection is
the periodontal ligament
Cartilaginous Joints:
,-Cartilaginous joints = bones united by cartilage
- No joint cavity
- Not highly movable
- 2 types of cartilaginous joints:
1.Synchondroses bar/plate of hyaline cartilage unites bones; ex: temporary
epiphyseal plate joints (joins diaphysis and epiphyses), which later become synostoses when
the plate closes; ex: cartilage of 1st rib and manubrium (joint between rib and sternum)
2.Symphyses ends of bone covered in hyaline cartilage, then fused to pad of
fibrocartilage; ex: intervertebral discs, pubic synthesis; strong, flexible amphiarthroses (slightly
movable)
Synovial Joints:
-Synovial joints = bones separated by fluid-filled joint cavity
- All are diarthrotic
- Include all limb joints; most joints of body
- 6 distinguishing features of synovial joints:
1. Articular cartilage hyaline cartilage at ends of bones; prevent the crushing of bone
ends
2. Joint (synovial) cavity small, fluid-filled potential space
3. Articular (joint) capsule consists of 2 layers: (1) External fibrous layer, which is the
extension of the periosteum and is made of dense irregular connective tissue; (2) Inner synovial
membrane, which makes the synovial fluid and is made of loose connective tissue
4. Synovial fluid viscous (thick/syrupy), slippery filtrate of plasma and hyaluronic
acid; lubricates and nourishes articular/hyaline cartilage; contains phagocytic cells to remove
microbes and debris
5. Different types of reinforcing ligaments (1) capsular, which is the thickened part
of the fibrous layer, (2) extracapsular, which is outside the capsule, and (3) intracapsular, which
is deep to the capsule and covered by the synovial membrane
6. Nerves and blood vessels nerve fibers detect pain, monitor joint position and
stretch; capillary beds supply filtrate for synovial fluid
- Other features of some synovial joints:
1. Fatty pads cushion between fibrous layer and synovial membrane or bone
2. Articular discs (menisci) fibrocartilage that separates articular surfaces to improve
“fit” of bone ends, stabilize joint, and reduce wear and tear
3. Bursae sacs lined with synovial membrane; contain synovial fluid; reduce friction
where ligaments, muscles, skin, tendons, or bones rub together; looks like a “ball” of synovial
fluid
4. Tendon sheaths “hot dog bun”; elongated bursa wrapped completely around
tendon subjected to friction
- 3 Stabilizing Factors at Synovial Joints:
1.Shapes of articular surfaces (minor role)
, 2. Ligament number and location (limited role)
3. Muscle tendons that cross joint (most important) muscle tone keeps tendons taut to
compensate for freely movable joint; extremely important in reinforcing shoulder and knee
joints and arches of the foot
- Stronger muscles = stronger joints
- Movements allowed at synovial joints:
-All muscles attach to bone or connective tissue at no fewer than 2 points:
1. Origin attachment to immovable bone
2. Insertion attachment to movable bone
- Muscle contraction causes insertion to move toward origin
- Movements occur along transverse, frontal, or sagittal planes
- Range of Motion of Synovial Joints:
1.Nonaxial slipping movements only
2. Uniaxial movement in one plane
3. Biaxial movement in two planes
4. Multiaxial movement in or around all three planes
- 3 General Types of Movements at Synovial Joints:
1.Gliding one flat bone surface glides or slips over another similar surface; ex: intercarpal
joints, intertarsal joints, between articular processes of vertebrae
2. Angular movements increase or decrease angle between two bones
- Movement along sagittal plane:
1. Flexion decreases the angle of a joint
2. Extension increases the angle of the joint
3. Hyperextension movement beyond the anatomical position
- Movement along frontal plane:
1. Abduction movement away from the midline
2. Adduction movement toward the midline
3. Circumduction involves flexion, abduction, extension, and adduction of
limb; limb describes cone in space
3. Rotation turning of bone around its own long axis toward midline (medial) or away from it
(lateral rotation; ex: between C1 and C2 vertebrae, rotation of humerus and femur
- Special Movements of Synovial Joints:
1.Supination and pronation of radius and ulna
2. Dorsiflexion and plantar flexion of foot
3. Inversion and eversion of foot
4. Protraction and retraction
5. Elevation and depression of mandible
6. Opposition of thumb and mandible
Chapter 8 – Joints:
Joints = Articulations:
-Articulation = site where two or more bones meet
- Functions of joints are to:
1.Give skeletal mobility
2. Hold skeleton together
- Two classifications of joints:
1.Functional
2. Structural
Functional Classification of Joints:
-Based on amount of movement joint allows
- 3 Functional Classifications:
1.Synarthroses immovable joints; ex: sutures; mainly axial skeleton
2. Amphiarthroses slightly movable joints; ex: pubic synthesis; mainly axial skeleton
3. Diarthroses freely movable joints; ex: most joints in limbs; mainly appendicular
skeleton
Structural Classification of Joints:
-Based on material binding bones together, and the presence/absence of a joint cavity
- 3 Structural Classifications:
1.Fibrous Joints
2. Cartilaginous Joints
3. Synovial Joints
Fibrous Joints:
-Fibrous joints = bones joined by dense fibrous connective tissue
- No joint cavity
- Most are synarthrotic (immovable)
- 3 types of fibrous joints:
1.Sutures seam; rigid, interlocking joints; immovable joints for protection of brain;
made of short connective tissue fibers, which allow for growth during youth; in middle age, the
fibers ossify and fuse (called synotoses)
2. Syndesmoses bones connected by ligaments (bands of fibrous tissue); fiber length
varies, so movement varies; ex: where tibia and fibula come together (tibiofibular joint); fibrous
tissue varies in length, but is always longer than sutures; more movable than sutures; large
amount of movement at interosseous membrane connecting radius and ulna
3. Gomphoses ped-in-socket joints of teeth in alveolar sockets; fibrous connection is
the periodontal ligament
Cartilaginous Joints:
,-Cartilaginous joints = bones united by cartilage
- No joint cavity
- Not highly movable
- 2 types of cartilaginous joints:
1.Synchondroses bar/plate of hyaline cartilage unites bones; ex: temporary
epiphyseal plate joints (joins diaphysis and epiphyses), which later become synostoses when
the plate closes; ex: cartilage of 1st rib and manubrium (joint between rib and sternum)
2.Symphyses ends of bone covered in hyaline cartilage, then fused to pad of
fibrocartilage; ex: intervertebral discs, pubic synthesis; strong, flexible amphiarthroses (slightly
movable)
Synovial Joints:
-Synovial joints = bones separated by fluid-filled joint cavity
- All are diarthrotic
- Include all limb joints; most joints of body
- 6 distinguishing features of synovial joints:
1. Articular cartilage hyaline cartilage at ends of bones; prevent the crushing of bone
ends
2. Joint (synovial) cavity small, fluid-filled potential space
3. Articular (joint) capsule consists of 2 layers: (1) External fibrous layer, which is the
extension of the periosteum and is made of dense irregular connective tissue; (2) Inner synovial
membrane, which makes the synovial fluid and is made of loose connective tissue
4. Synovial fluid viscous (thick/syrupy), slippery filtrate of plasma and hyaluronic
acid; lubricates and nourishes articular/hyaline cartilage; contains phagocytic cells to remove
microbes and debris
5. Different types of reinforcing ligaments (1) capsular, which is the thickened part
of the fibrous layer, (2) extracapsular, which is outside the capsule, and (3) intracapsular, which
is deep to the capsule and covered by the synovial membrane
6. Nerves and blood vessels nerve fibers detect pain, monitor joint position and
stretch; capillary beds supply filtrate for synovial fluid
- Other features of some synovial joints:
1. Fatty pads cushion between fibrous layer and synovial membrane or bone
2. Articular discs (menisci) fibrocartilage that separates articular surfaces to improve
“fit” of bone ends, stabilize joint, and reduce wear and tear
3. Bursae sacs lined with synovial membrane; contain synovial fluid; reduce friction
where ligaments, muscles, skin, tendons, or bones rub together; looks like a “ball” of synovial
fluid
4. Tendon sheaths “hot dog bun”; elongated bursa wrapped completely around
tendon subjected to friction
- 3 Stabilizing Factors at Synovial Joints:
1.Shapes of articular surfaces (minor role)
, 2. Ligament number and location (limited role)
3. Muscle tendons that cross joint (most important) muscle tone keeps tendons taut to
compensate for freely movable joint; extremely important in reinforcing shoulder and knee
joints and arches of the foot
- Stronger muscles = stronger joints
- Movements allowed at synovial joints:
-All muscles attach to bone or connective tissue at no fewer than 2 points:
1. Origin attachment to immovable bone
2. Insertion attachment to movable bone
- Muscle contraction causes insertion to move toward origin
- Movements occur along transverse, frontal, or sagittal planes
- Range of Motion of Synovial Joints:
1.Nonaxial slipping movements only
2. Uniaxial movement in one plane
3. Biaxial movement in two planes
4. Multiaxial movement in or around all three planes
- 3 General Types of Movements at Synovial Joints:
1.Gliding one flat bone surface glides or slips over another similar surface; ex: intercarpal
joints, intertarsal joints, between articular processes of vertebrae
2. Angular movements increase or decrease angle between two bones
- Movement along sagittal plane:
1. Flexion decreases the angle of a joint
2. Extension increases the angle of the joint
3. Hyperextension movement beyond the anatomical position
- Movement along frontal plane:
1. Abduction movement away from the midline
2. Adduction movement toward the midline
3. Circumduction involves flexion, abduction, extension, and adduction of
limb; limb describes cone in space
3. Rotation turning of bone around its own long axis toward midline (medial) or away from it
(lateral rotation; ex: between C1 and C2 vertebrae, rotation of humerus and femur
- Special Movements of Synovial Joints:
1.Supination and pronation of radius and ulna
2. Dorsiflexion and plantar flexion of foot
3. Inversion and eversion of foot
4. Protraction and retraction
5. Elevation and depression of mandible
6. Opposition of thumb and mandible
