Joints Flashcards
What are joints?
Regions of the skeleton where bones meet and articulate with each other
Supported by a variety of soft tissues
What is the function of joints?
Function is either to allow movement or growth
How are joints classified?
There is no single best way to classify joints but classification is usually based on either the degree of movement possible or the nature of the soft tissues involved
What are the classifications of joints?
Fibrous- bones are only separated by connective tissue with negligible movement
Cartilage
- primary cartilaginous (synchondrosis)
- secondary cartilaginous (symphysis)
Synovial
-Characterized by 6 criteria
Explain fibrous joints as a classification
Sutures
- Immovable
- Dense irregular connective tissue between bones
Syndesmosis
- slight movement
- greater distance
- More connective tissue
- Gomphosis- teeth
Interosseous membrane
Explain Cartilaginous joints
Synchondrosis
- bone and hyaline cartillage meet
- immobile
- very strong
- Epiphyseal growth plate
Symphysis
- Articular surfaces lined with hyaline cartilage with a fibrocartilage disc in between
- Limited amount of movement
- pubic symphysis
- intervertebral joints
Explain synovial joints
- Articular surfaces covered with hyaline cartilage
- Has a joint cavity
- has a joint capsule
- Has a synovial membrane
- Reinforced by ligaments internally, externally or both
- Capable of varying degrees of movement
What are the classes of synovial joints?
- plane joint
- hinge joint
- pivot joint
- condyloid joint
- saddle joint
- ball-and-socket
What is a plane joint?
Type of synovial joint that is between navicular and second and third cuneiforms of tarsus in foot
What is a hinge joint?
Synovial joint between trochlea of humerus and trochlear notch of ulna at the elbow
What is the pivot joint?
Synovial joint between head of radius and radial notch of ulna
What is the condyloid joint?
Synovial joint between radius and scaphoid and lunate bones and carpus (wrist)
What is the saddle joint?
Synovial joint between trapezium of carpus (wrist) and metacarpal of thumb
What is a ball-and-socket joint?
Synovial joint between head of femur and acetubulum of hip bone
Describe gliding movements
- flat bone surfaces
- limited in range
- no significant alteration in angle
Describe angular movements
-change in angle
-described in terms f the body planes
Flexion-extension
Abduction-adduction
Lateral flexion, hyper extension , curcumduction
Describe rotational movement
- a bone revolves around its own longitudinal axis
- Ususlly requires “fixing” another joint before rotation can be achieved
- At limbs this is defined in relation to the midline
- Medial/internal rotation
What is the temporomandibular joint?
Classification: -atypical synovial joint
-modified hinge/condylar
Articular surfaces:
-Condyle of the mandible
- Articular tubercle of temporal bone
- Mandibular fossa
What is the Glenohumeral joint ?
Articulation between
-head of humerus and glenoid cavity
Highly mobile at expense of stability
The factors increasing stability:
-Bony arch
- Rotator cuff
- Ligaments both intra- and extra-capsular
What is a dislocation?
Dislocation usually occur inferno-anteriorly in the absence of fracture - shoulder joint is weakest inferiorly. It’s very painful.
Once dislocated, can reoccur
What bodily prevents dislocation for the shoulder?
Superior support
-bony arch
Anterior and posterior support
-Ligaments
- biceps long head tendon
- rotator cuff muscles- mainly during movement
Describe the hip joint
- More stable than shoulder and somewhat less mobile
- weight-bearing joint
- femur neck features often in elderly
- osteoporosis
- can be devastating
What are the age related changes?
- decreased production of synovial fluid
- Articular cartilage becomes thinner
- Mainly on weight-bearing joints
- knees and hips
-osteoarthritis
