Joints Flashcards
What is a joint?
A joint is the physical point of connection between 2 bones.
What is the function of joints?
Joints are constructed to allow movement (articulation) and provide mechanical support (stability).
What are joints named according to? Give an example.
Joints are named according to bones they connect e.g. temporal bone & mandible = temporomandibular joint
Functional classification looks at whether or not the joint moves. There are 3 classifications within this:
- ______ - non-movable
- _________ - slightly movable
- ________ - freely movable
Functional classification looks at whether or not the joint moves. There are 3 classifications within this:
- SYNARTHROSIS - non-movable
- AMPHIARTHOSIS - slightly movable
- DIARTHROSIS - freely movable
Structural joint classification looks at the way bones ______, and is a more precise way of classifying joints. Again, there are 3 classifications within this:
- _____ – joined by dense fibrous connective tissue
- _________ – joined by cartilage
- ______ – not directly joined, instead the bones have a synovial cavity & are united by a capsule, which allows movement
Structural joint classification looks at the way bones CONNECT, and is a more precise way of classifying joints. There are 3 classifications within this:
- FIBROUS – joined by dense fibrous connective tissue
- CARTILAGINOUS – joined by cartilage
- SYNOVIAL – not directly joined, instead the bones have a synovial cavity & are united by a capsule, which allows movement
Fibrous joints are within _______ classification. Bones joined by fibrous _______ tissue. There is minimal or no ________. Fibrous joints can be further classified:
a) ______ = bones often interdigitate, e.g. _____
b) _______ = bones further apart, joined by ligaments, e.g. ______ and _____
c) _______ = pegs in sockets, held in place by connective tissue, e.g. _____
Fibrous joints are within STRUCTURAL classification. Bones joined by fibrous CONNECTIVE tissue. There is minimal or no MOVEMENT. Fibrous joints can be further classified:
a) SUTURES = bones often interdigitate, e.g. SKULL
b) SYNDESMOSES = bones further apart, joined by ligaments, e.g. TIBIA and FIBIA
c) GOMPHOSES = pegs in sockets, held in place by connective tissue, e.g. TEETH
Describe sutures (structural > fibrous > sutures).
Sutures are where opposing bones integrate. They are strong. They are non-movable joints (synarthrosis). They are found in the skull. In adults, sutures often completely ossify.
Describe frontanels.
Hint: think sutures!!
Fontanels are the membranous areas between skull bones in baby, which allow change in head shape for birth & rapid growth after birth
Describe syndesmoses (structural > fibrous > syndesmoses)
The bones are farther apart than suture. It is a slightly movable joint (amphiaryhrosis). The bones are joined by fibrous ligaments E.g radioulnar
Describe gomphoses (structural > fibrous > gomphoses)
They are non-movable joints (Synarthrosis). these are specialized joints, e.g. teeth. They are like pegs fit into sockets.
Periodontal ligaments: hold teeth in place
What is periodontal disease?
Periodontal disease is when plaque & bacteria accumulate, causing inflammation and destroying periodontal ligaments & bone – loose teeth
Describe cartilaginous joints.
The bones are joined by cartilage (often strengthen by ligaments). These allow limited movement.
They can be further classified into 2 groups:
a) Symphyses = fibrocartilage
b) Synchondrosis = hyaline cartilage
Describe the 3 types of elastic cartilage (elastic, fibrocartilage, hyaline) and give examples of each type.
Elastic: elastic fibres + collagen & proteoglycans, rigid but elastic properties e.g. External ears
Fibrocartilage – more collagen than proteoglycans (strongest), Thicker bundles of collagen fibres, Slightly compressible, deals with pressure points e.g. intervertebral disks.
Hyaline – equal collagen + proteoglycans (weakest), Collagen fibres evenly dispersed, smooth, translucent, Abundant, strong support but flexible e.g. shoulder, Covers surface of bones to reduce friction & shock
Describe symphyses (structual > cartilaginous > symphyses) and give examples.
It is fibrocartilage uniting two bones. It is slightly movable (Amphiarthrosis)
E.g. symphysis pubis, between manubrium & body of the sternum, intervertebral disks.
Describe syndochroses (structual > cartilaginous > syndochroses)
Bones are joined by hyaline cartilage. The joints are unmovable (Synarthrosis)
Some are temporary & replaced by suture, e.g. Epiphyseal plate connecting epiphysis & diaphysis of growing bone, while some are permanent
Describe synovial joints.
Synovial joints are one of the structural classifications. Bones don’t directly join. Bones are enclosed in a cavity surrounded by a capsule, which holds bones together. It contains synovial fluid.
Articulating bone surfaces are covered in hyaline/articular cartilage
Movement limited by shape of articular surfaces and arrangement of ligaments E.g. Joints in limbs (Diarthrosis).
Describe bursae. What is bursitis?
This is a synovial membrane which extends as a pocket away from rest of joint cavity, and contain synovial fluid.
They are found in areas of friction to cushion between structures in certain synovial joints (e.g. knee, shoulder)
Bursitis = inflammation of a bursa, causes considerable pain around the joint and restrict movement
Describe the 6 groups synovial joints can be further classified into (plane joint, hinge joint, ball and socket joint, saddle joint, pivot joint, ellipsoid joint) and give an example for each type.
Plane joint: between flat bone, sliding, uniaxial, e.g. articular processes between vertebrae
Hinge joint: uniaxial, flexion/extension, e.g. knee
Ball and socket joint: multiaxial, free movement, flexion, extension and rotation, e.g. hip
Saddle joint: biaxial, flexion/extension, e.g. carpo-metacarpal thumb
Pivot joint: uniaxial rotation, e.g. radio-ulnar joint
Ellipsoid joint: biaxial, flexion/extension, modified ball & socket, AKA Chondyloid, e.g. atlantoocipital joint (very top of spine and base of skull)
Describe ligaments and tendons.
Ligaments connect bone to bone. They are a tough, flexible, fibrous connective tissue.
Tendons connect muscle to bone. They are a flexible but inelastic cord of strong fibrous collagen tissue.
Describe the following movements:
Extension Flexion Abduction Adduction Rotation Pronation Supination Circumduction
Extension: posterior to coronal plane
Flexion: anterior to coronal plane
Abduction: away from medial plane
Adduction: toward medial plane
Rotation: turning on it’s axis, medial and lateral rotation
Pronation: unique rotation of forearm with palms facing posteriorly
Supination: unique rotation of forearm with palms facing anteriorly
Circumduction: combination of flexion, extension, abduction and auction.
Describe the following “special” movements:
Elevation Depression Protraction Retraction Opposition Reposition
Elevation: moves a structure superior
Depression: moves a structure inferior
Protraction: gliding motion anteriorly
Retraction: moves structure back to anatomic position or even back further posteriorly
Opposition: movement of them and finger towards each other
Reposition: return fingers to anatomical position
Amount of mobility at a given joint influenced by;
- Shape of _____ surfaces forming joint
- Amount & shape of ______ covering surfaces
- Strength & location of ______ & ______
- Location of_____ associated with joint
- Amount of _____ in and around joint
- Amount of __/_____ of joint
- Amount of ___ in and around joint
Amount of mobility at a given joint influenced by;
- Shape of ARTICULAR surfaces forming joint
- Amount & shape of CARTILAGE covering surfaces
- Strength & location of LIGAMENTS & TENDONS
- Location of MUSCLES associated with joint
- Amount of FLUID in and around joint
- Amount of USE/DISUSE of joint
- Amount of PAIN in and around joint
Describe the effects of waging on joints.
Tissue repair slows; new blood vessel development decreases
Articular cartilages wear down
Production of synovial fluid declines
Ligaments & tendons shorter & less flexible
Muscles around joints weaken
A decrease in activity causes less flexibility
Describe osteoporosis.
It results in“porous bone” due to loss of bone matrix which weakens bone, making them more prone to bending & fracture
Causes; decreased estrogen, poor diet (Ca), lack of exercise.
2.5x more common in women
Describe arthritis. Also describe osteoarthritis and rheumatoid arthritis.
Arthritis is an inflammation of joints, leading to pain & stiffness. There are over 100 causes including infectious agents, metabolic disorders, trauma and immune disorders.
Osteoarthritis = Degenerative, most common; affects 85% of Americans >70yrs; gradual degeneration of a joint with advancing age; delayed with exercise
Rheumatoid arthritis = General connective tissue autoimmune disorder that predominantly affects joints.
What is tenditis?
Inflammation of tendon sheaths, often from overuse, e.g. tennis elbow
Describe dislocations.
Movement of bones out of correct alignment at a joint; partial dislocation=subluxation
What is a sprain?
Stretching or tearing of ligaments supporting a joint
