Joints Flashcards
Joint definition
Articulation between two or more bones, which can be mobile or immobile
What is the stability of the joint dependent on?
shape and size of articular surface
thickness of surrounding join capsule
skeletal muscles and tendons passing across the joint
ligaments associated with the joint
Structure of ligaments
composed of collagen fibres arranged in parallel arrays containing. varying amount of elastin protein
Associated structures with joints
tendons, ligaments and bursae
Ligament origin
arise from periosteum of bone involved
tendon structure
strip of tough collagenous connective tissue attaching muscle to bone
bursa structure + function
fibrous sac filled with synovial fluid located between adjacent muscles, where a tendon passes over bone and between bone and skin.
Joints of the upper limb
acromioclavicular, sternoclavicular, glenohumeral, elbow, proximal and distal radioulnar, radiocarpal, carpal metacarpal, intercarpal, metacarpophalangeal, interosseous membrane
Acromioclavicular structure explained + movement available
lateral clavicle edge and medial acromion
plane synovial- contained in a joint capsule
articular surfaces lined by fibrocartilage and fibrocartilaginous articular disc
little movement available
what stabilises the acromioclavicular joint?
stabilised by fibres of the trapezius and deltoid
acromioclavicular ligament
coracoclavicular ligament- attaches under surface of the clavicle to the coracoid of the scapula
sternoclavicular joint structure explained +
- between upper lateral edge of manubrium of sternum and medial clavicle
- saddle type synovial joint- very strong and allows a lot of movement - very mobile
atypical synovial joint- surfaces covered in fibrocartilage with a fibrocartilaginous disc - allows the sternum and the clavicle to move over when another more easily
movement available at sternoclavicular joint
depression, elevation, protraction, retraction, medial + lateral rotation
How is the sternoclavicular joint strengthened?
anterior and posterior sternoclavicular ligaments and costoclavicular ligaments - attaches to inferior rib
What dislocation often occurs?
Anterior, as the anterior sternoclavicular ligament is weaker
What dislocation occurs with acromioclavicular joint? + why?
anterior
patient falls onto shoulder- force from the fall pushes the scapula down- collarbone cannot move to follow the motion of the scapula
- ligaments around the AC tear
Glenohumeral structure explained
Head of humorous articulates with glenoid fossa of the scapula
ball and socket synovial joint- lined with synovial which secretes synovial fluid
fibrous joint capsule sheath encloses the joint which extends form the anatomical neck of the heroes to the border of the glenoid fossa-
synovial bursae- subscapular and subacromial
Mobility of glenohumeral joint enhanced by ?
- joint capsule is lax
- ball and socket joint type
- bony surfaces- relatively shallow glenoid fossa and large humeral head
stability enhanced by?
- glenoid labrum- a fibrocartilaginous ring that deepens the socket, reducing the risk of dislocation
- glenohumeral ligaments- relatively weak- reinforce anterior aspect- running with the glenoid labrum joint capsule
- coracohumeral- connects coracoid process to the greater tubercle - reinforces superior part of capsule
- transverse humeral ligament- spans from the tubercles to keep the biceps brachii tendon firm in the inter tubercular groove
- stabilised by biceps on anterior aspect - inserts into glenoid labrum
- rotator cuff muscles - attached via tendons that fuse with the joint capsule on all sides except inferior
Movement at glenohumeral joint
flexion/extension, circumduction, medial/lateral rotation and flexion/extension
dislocations at the glenohumeral joint
- anterior dislocation of humeral head, due to the lack of stabilisation at the inferior region of the joint- back muscles prevent posterior dislocation
Elbow joint structure explained
Synovial hinge joint- flexion and extension
three articulations- humeroulnar joint- trochlea notch of ulna and trochlea of humorous
humeroradial- head of radius and capitulum
head of radius and radial notch of ulna- proximal radioulnar joint
- all enclosed in a single capsule
Ligaments in elbow joint
Medial collateral- medial epicondyle to olecranon of ulna
lateral collateral- lateral epicondyle to the annular ligament of radial notch of ulnar
structure of capsule
fibrous capsule encloses elbow joints- attaches to annular ligament
strengthens- thickens medially and laterally to form collateral ligaments
Bursa names
intratendinous, subtendinous and subcutaneous bursa
radio ulnar joint structures explained
pivot synovial joint- responsible for pronation and supination of the forearm
annular radial ligament in proximal- allows movement however acts like a sling
distal
- ulna notch and head of ulna
- surrounded by weak loose fibrous capsule
- anterior and posterior collateral ligament
- intra-articular disc which binds the radius and ulna together
Function of intra articulating disc
binds radius and ulna together
attaches to medial styloid process- distal end of ulna articulates with disc and not carpals
interosseous membrane structure and function
syndesmoses- fibrous sheet of connective tissue between shafts
small holes in sheet for vessels to pass through
fibres pass distally from radius to ulnar- transfers compressive forces
stability during pronation and supination
acts as a muscle attachment site
Dislocation of radius
radial head pulled out of annular ligament, especially in children, called nursemaid’s elbow
posterior dislocation when falling on outstretched hand
Radiocarpal joint structure explained + movement
synovial elipsoid joint
articulation between radius and convex structure formed by scaphoid, lunate and triquetrium
does not articulate with pisiform as sesamoid therefore within the tendon of the wrist
strengthened medially and laterally by radial and ulnar collateral ligaments
flexion, extension, abduction and adduction and circumduction
Carpal tunnel structure
transverse carpal ligament that passes over palmar surface that holds the flexor tendons in place
Carpal tunnel syndrome
median nerve becomes compressed as it passes through carpal tunnel
mid carpal and inter carpal joint types
plane synovial- permit flexion and extension
first carpometacarpal joint structure + function
thumb- between first metacarpal bone and trapezium
forms synovial saddle joint
enables opposition- that enables the thumb to touch its other digits
other joint types
carpometacarpal- plane
metacarpal phalangeal- synovial ellipsoid
interphalangeal- hinge
Joints of the lower limb
pubic symphysis, sacroiliac, acetabulofemoral, knee, distal and proximal tibiofibular, interosseous membrane, talocrural, sub talar, intertarsal, tarsometatarsal, metatarsalphalangeal, inter phalangeal
structure of pubic symphysis explained + movement
secondary cartilaginous joint between two pubis bones
articulating surfaces covered in hyaline cartilage and united by a fibrocartilaginous disc
movements usually limited but mobility during pregnancy
sacroiliac structure and movement
- limited movement and weight bearing
between the sacrum and articular surface of the ilium
atypical synovial joint- one articular surface in hyaline cartilage and the other in fibrocartilage
synovial plane joint
surfaces are irregular- interlock preventing movement
sacrotuberus and sacrospinous ligaments resist forward rotatory thrust
interosseous sacroiliac ligaments limit movement- posterior, anterior
Explain structure of hip joint
- synovial ball and socket
between pelvic acetabulum and femur head
- thick cartilage- more weight bearing
- capsule surrounds the joint, synovial membrane lines capsule and all surfaces without hyaline cartilage
Factors that increase stability
Acetabulum is very deep- deepens further by acetabular labrum
head of femurs hemispherical and fits completely in the deep acetabulum- decreases the risk of dislocation - increased surface area in contact
round ligamentum teres- intracapsular ligament- arises from fovea capitiis and attaches to lower transverse ligament of the acetubulum- relatively slack so little role
transverse acetabular ligament- bridges the notch in the inferior margin of the acetulum to complete the socket- limiting anterior, inferior dislocations
3 extra capsular ligaments + structure
iliofemoral - iliac spine and intertrochanteric line of femur. inverted Y shape that prevents overextension- anterior strongest
ischiofemoral- body of ischium behind acetabulum to anterior region of femur- spiral shape prevents hyperextension
pubofemoral- superior pubic rami to the inferior aspect of the neck of the femur- prevents excessive abduction and extension
Knee joints named
tibiofemoral joint and patellofemoral joint
Tibiofemoral joint structure explained
hinge joint- however when flexed can also slightly rotate and glide laterall- between the medial and lateral condyles of the femur and the tibial plateau- weight bearing
no articulation with fibula
surface of hyaline cartilage
distal portion of femur widened into condyles to spread the compressive forces of the trunk over a wider area
joint capsule encloses the lateral and posterior aspects of the knee joint but not anterior, as this is where the patella is
Structure of patellofemoral joint
sesamoid patella found embedded in quadriceps tendon
articulates with the anterior distal femur
plane synovial joint
quadriceps tendon becomes the patella ligament and inserts into tibial tuberosity
Structure within capsule
medial and lateral menisci- two C shaped fibrocartilage structures found within the cavity, attached at both ends to the intercondylar area of the tibia
medial meniscus is bigger - joints to capsule and tibial collateral ligament
structure and location + function
anterior and inferior cruciate ligaments lie deep within the joint, however are excluded from the synovial capsule
anterior- attaches to posterior aspect of the lateral condyle of the femur and anterior upper region of tibia
- shorter
- ACL is pulled tight and prevents hyperextension
posterior- anterior inner aspect of medial condyle and posterior upper tibia
- prevents posterior dislocation of the tibia
prevents femur sliding off the tibia
Other important ligaments present
collateral ligaments- medial and lateral- reinforce hinge joint
- prevent medial and lateral rotation in extension
- medial fused with meniscus
oblique popliteal ligament
- crosses the posterior of the knee joint
- fibrous band that is an extension of the semimembranous tendon
- resists torsional stresses
- limits rotation when the knee locks
Bursa present in knee
supra patellar bursa- beneath quadricep
prepatellar- in front of patella
subcutaneous bursa- sandwich patellar ligament
Common knee injuries
menisci tears- due to excessive force from a twist or rotation
ACL injury- caused by excessive pivot, suddenly changing direction
Tibiofibular joints structures and functions
superior- plane synovial between head of fibula and lateral condyle of tibia, allows fibular to rotate slightly as the talus moves
distal- syndesmoses- very little movement
ankle joint name and articulations
talocrural joint
medial joint- between malleolus and distal end of tibia and talus
lateral joint- malleolus and distal end of the fibula and talus
talocrural joint structure and function
compound synovial hinge joint that allows dorsiflexion and plantar flexion
malleoli of tibia and fibula overhand the talus on each side like a cap, preventing ad and abduction (limited dexterity)
2 types of ligaments
medial (deltoid) ligaments - consists of 4 separate ligaments that fan out from the tibia malleolus and attach to talus, calcaneus and navicular bone, resting over eversion of foot
lateral ligaments- 3 serrate ligaments:
- anteriotalofibular
- calcaneoufibular
- posterior talofibular
Other adaptations of the foot that increases support
extensor and flexor retinacula- which are bands of dense connective tissue that hold the tendons in place
plantar fascia- strong layer of fibrous tissue on the sole of the foot
subtalar joint structure explained
talocalcaneal- synovial plane joint
talocalcaneonavicular - synvovial ball and socket joint
curvatures of two articulating surfaces permits eversion and inversion
Two main joint disorders explained
osteoarthritis- loss of hyaline cartilage between bones- wear and tear- typically large, weight bearing bones
juvenile arthitis- autoimmune disease that leads to the destruction of synovial membranes
