Chapter 8 - Articulations Flashcards
Points of contact between joints
- Between two bones
- Between cartilage and bone
- Between teeth and bones
Hold bones together but may permit movement
Joints
Study of joints
Arthrology
Study of motion
Kinesiology
Three classifications of joints based on movement
- Synarthrosis = immovable
- Amphiarthrosis = slightly
- Diarthrosis = freely
Classifications of joints based on anatomy
- Fibrous (collagen fibers)
- Cartilaginous (cartilage)
- Synovial (joint capsule and accesory ligaments)
Joints that lack a synovial cavity
Fibrous joints
What are fibrous joints held together by?
Fibrous connective tissue
How much movement do fibrous joints have?
Little or none (synarthroses or amphiarthroses)
Three structural types of fibrous joints
- Sutures
- Syndesmoses
- Gomphoses
Three characteristics of sutures
- Thin layer of dense fibrous connective tissue unites bones of the skull
- Immovable (synarthrosis)
- If fused completely in adults is synostosis
Three characteristics of Sydesmosis
- Fibrous joint
- Bones united by ligament
- lightly movable (amphiarthrosis)
Where are syndesmosis joints?
Anterior tibiofibular and interosseous membrane
What is a gomphosis joint and what kind of movement does it have?
- Ligament holds cone-shaped peg in bony socket
- Immovable (synarthrosis)
Where are the gomphosis joints?
- Teeth in alveolar processes of maxillae or mandible
- Lacks a synovial cavity
- Allows little or no movement
- Bones tightly connected by fibrocartilage or hyaline cartilage
Cartilage joints
Two types of cartilage joints
- Synchondross
2. Symphyses
Connecting material in synchondrosis joints
Hyaline cartilage
Movement in synchondrosis joints
Immovable (synarthrosis)
Where are synchondrosis joints?
Epiphyseal plate or joints between ribs and sternum
In synchondrosis, when fusion occurs, it becomes a _____
Synostosis
Connecting material in symphysis joints
Fibrocartilage
Movement in symphysis joints?
Slightly movable (amphiarthroses)
Where are the symphysis joints?
- Intervertebral discs
- Pubic symphysis
Synovial joint features
- 2 bones separated by fluid filled cavity
2. Joint capsules has 2 layers
Two layers of joints capsules
- Synovial membrane
2. Articular cartilage
Synovial fluid components
- Blood filtrate
- Hyaluronic acid
- Glycoproteins
Synovial fluid functions
- Lubricate joint surfaces
- Nourish chondrocytes
- Shock absorber
What do ligaments do?
- Reinforce and strengthen joint capsules
- Connect bone to bone with dense regular CT
Two ligament types
- Extracapsular ligaments
2. Intracapsular ligaments
- Outside joint capsules
- Collaterals
Extracapsular ligaments
- Ligaments within capsules
- Cruciates (ex ACL)
Intracapsular ligaments
- Pads of fibrous cartilage that subdivide a cavity
Articular discs
Another name for articular discs
Menisci
Example of articular discs (menisci)
- Ulnolunate joint
- Knee joint
Articular disc functions
- Channel flow of synovial fluid
- Modify articular surfaces
- Restrict movements at joint
- Cushion articulating surfaces
- Help distribute body weight
Adipose tissue surrounding the synovial capsule
Fat pads
Example of fat pads
Tibiofemoral joint
Functions of fat pads
- Protect articular cartilage
- Packing material
- Fills spaces when joint changes shape
Small, fluid filled pockets of connective tissue
Bursae
Location and Functions of bursae
Location: Hypodermis; between tendons, ligaments, and bones
Function: Cushion and support; aid in movements of tendons
Two opposing surfaces that slide past each other
Gliding
A change in angle between the shaft and the articular surface
Angular movement
- A type of angular motion
- Rotation of the shaft while changing the angle
Circumduction
Spinning of the shaft without changing the angle
Rotation
Types of angular motion
- Abduction
- Adduction
- Flexion
- Extension
- Hyperextension
Types of rotation
- Pronation
- Supination
Special movements
- Eversion/inversion
- Dorsiflexion/ Plantar flexion
- Lateral flexion
- Protraction/ Retraction
- Opposition
- Elevation/ Depression
Making the angle smaller in body movement
Flexion
Moving the body back to anatomical position
Extension
The trade off between flexibility and stability in synovial joints are due to
- Shape of articulating surfaces
- Tightness of ligaments
- Presence of accessory ligaments
- Other factors: other bones, muscles or fat pads
Types of synovial joints
- Plane
- Hinge
- Pivot
- Condylar
- Saddle
- Ball and socket
- Bone surfaces are flat or slightly curved
- Side to side movement only
- Rotation prevented by ligaments
Plane joint
Examples of plane joints
- Intercarpal or intertarsal joints
- Sternoclavicular joint
- Vertebrocostal joints
If you bring your mandible forward (underbite)
Protraction
- Convex surface of one bones fits into concave surface of 2nd bone
- UNIAXIAL like a door hinge
Hinge joint
Examples of hinge joints
- Knee
- Elbow
- Ankle
- Interphalangeal joints
Movements produced from the hinge joint (also define their meanings)
Flexion: decreasing the joint angle
Extension: increasing the angle
Hyperextension: opening the joint beyond the anatomical position
- Rounded surface of bone articulates with ring formed by 2nd bone and ligament
Pivot joint
Is the pivot joint uniaxial? If so, why?
It allows only rotation around longitudinal axis
Examples of pivot joints
- Proximal radioulnar joints
2. Atlanto-axial joint
Movements that are in the proximal radioulnar joint
- Supination and pronation
Movement in the atlanto-axial joint
Turning head side to side to say “no”
- Oval shaped projection fits into oval depression
- BIAXIAL
Condylar joint
Flex/extend or abduct/adduct is possible
Biaxial
Examples of where condylar joints are
- Wrist
- Metacarpophalangeal joints for digits 2 and 5
One bone saddled-shaped; other bone fits as a person would sitting in that saddle
Saddle joint
Why is the saddle joint biaxial?
- Circumduction allows tip of thumb travel in circle
- Opposition allows tip of thumb to touch tip of other fingers
Examples of saddle joints
- Trapezium of carpus and metacarpal of the thumb
Ball fitting into a cuplike depression
Ball and socket joint
Why is the ball and socket joint multiaxial?
Because of…
- Flexion/extension
- Abduction/adduction
- Rotation
Examples of ball and socket joints
- Shoulder joint
- Hip joint
- Hinge joint
- Condyles slide back and forth along sockets
- 2 synovial joints
Temporomandibular joint
What is the TMJ between?
Between the condylar process of mandible and mandibular fossa
Where do the vertebrate articulate?
Between the superior and inferior articular processes
What kind of joint is in intervertebral articulations?
Plane joint
What does intervertebral articulations restrict?
Restrict lateral movement
These allow flexion, extension, lateral flexion and rotation in the intervertebral articulations
Discs
Two parts to the intervertebral disc and the components to each part
- Anulus fibrous: fibrocartilage
2. Nucleus pulposus: 75% water, hyaluronic acid, reticular and elastic fibers
- Slipped disc
- Nucleus pulposus breaks through annulus fibrous
- Movements of vertebral column compress nucleus
Herniated disc
Describe the joints in the shoulder
- Glenohumeral joint
What are the components to the Glenohumeral joint?
Head of humerus meets glenoid cavity
The glenoid cavity is covered by what?
Glenoid labrum
A ringe of dense irregular connective tissue attached to the margin of the glenoid cavity
Glenoid labrum
Two joints in the elbow
- Humerus and ulna (hinge, flexion/extension)
2. Ulna and Radius (pivot and pronation/supination)
Joints in the wrist and hand
- Radiocarpal joint
- Intercarpal
- Carpometacarpal
- Metacarpophalangeal
- Interphalangeal
Movements in the radiocarpal joint
- Between radius and 3 prox. carpels
- Flexion/extension
- Abduction/adduction
- Circumduction
Movement in intercarpal joints
Gliding
Movement in the carpometacarpal joints
Thumb: saddle
Other digits: plane (sliding)
Movement in metacarpophalangeal joints
Hand to fingers (condylar)
- Abbduction/adduction
- Flexion/ extension
Movement in interphalangeal joints
Fingers (hinge)
- Flexion/extnsion
Two bones making up the hip joint
- Femoral head
2. Acetabulum of pelvis
Extends the size of the acetabulum
Labrum
Movement in hip joint
ball and socket
The knee joint must …
- Support body mass
- Have up to 160 degrees motion
- Be unobstructed by muscle (like hip)
- Lack strong yet limiting ligaments (like ankle)
Two joints in the knee
- Tibiofemoral joint
2. Patellofemoral joint
Movement in the tibiofemoral joint
Hinge
- Flexion/extension
- Some rotation (less stable than most hinge joints)
Movements in the patellofemoral joint
Plane - sliding
Ankle joint
Talocrural joint
Ankle and foot joints
- Tibiotalar
- Tibiofibular
- Firbulotalor
Movement in the ankle and the foot bones
Dorsi/plantiflexion
Foot joints
- Intersarsal
- Tarsometatarsal
- Metatarsophalangeal
- Interphalangeal
The plane joints between the tarsals
Intertarsals
Plane joints between tarsals and metatarsals
Tarsometatarsal
Condylar joints between metatarsals and digits
Metatarsophalangeal
Hinge joints in digits
Interphalangeal
