Lecture 1 - Basic concepts Flashcards
6 functions of bone
Support Protection e.g skull Metabolism Storage e.g calcium phosphate Movement Haematopoiesis
6 functions of skeletal muscle
Locomotion Posture - postural muscles Metabolism - glycogen Venous return Heat production - shivering Continence - pelvic floor muscles
Types of connective tissue
Tendon - bone to muscle
Ligament - bone to bone
Fascia - compartmentalisation of muscles
Cartilage - hyaline/ fibrous
Synovial membrane
Found within joints, bursae and tendon sheaths
Produces synovial fluid which lubricates joints
3 classifications of joints
Fibrous
Cartilaginous
Synovial
Fibrous joints
Collagen fibres
Very limited mobility
High stability
Examples of fibrous joints
Sutures of the skull
Inferior tibiofibular joint (ankle)
Joint between the roots of a tooth and the bone of the mandible or maxilla
Radioulna interosseous membrane (forearm)
Posterior sacroiliac joint (Pelvis)
Cartilaginous joints
Hyaline cartilage
Found in the midline typically and in epiphyseal plates of long bones
Primary cartilaginous joints
Completely immobile
Hyaline cartilage
First sternocostal joint
Epiphyseal growth plates
Secondary cartilaginous joints
Also known as symphases
Articulating bones covered with hyaline cartilage with a pad of fibrocartilage between them
E.g symphysis pubis
Intervertebral discs
Manubriosternal joint
Periosteum arteries
Supply the periosteum and the outer third of the cortex of bone
Metaphyseal arteries
Enter at the site of attachment of the capsule
Children- do not cross the growth plates
Adulthood - anastomosis formed between the epiphyseal and metaphyseal arteries
Avascular necrosis
Death of bone due to the lack of blood supply
Common cause:
Fracture
Other cause:
alcoholism
Excessive steroid use
Thrombosis
Hypertension
Decompression sickness - small bubble of nitrogen which impede blood supply
Radiation - obliteration of small arteries
Bone remodelling
Response to environmental factors
E.g sustained application to load
Change in balance between osteoclast and osteoblasts activity
I.e increased use - higher osteoblasts activity therefore thicker
Synovial joints
Joint cavity containing synovial fluid
Articulating surfaces covered in hyaline cartilage - avascular
Fibrous capsule
Synovial membrane
Synovial fluid function
Provides lubrication to the articulating surfaces
Prevents friction
Shock absorber
Transport nutrients and waste products to and from articulate cartilage
Synovial articulating surfaces
- hyaline cartilage
- smooth,low friction movements
- resists compressive forces - shock absorber
Fibrous capsule
composed of collagen in longitudinal and interlacing bundles.
Encloses joint
Except at bursae - synovial protrusions
Poor blood supply
Stabilises joint
Permits movement
Resists dislocation
Continuous with the periosteum
Synovial membrane
Thin
Highly vascularised- rich blood supply- transfer of nutrients
Produces synovial fluid
Lines joint capsule and covers any exposed osseous surfaces
Lines tendon sheaths and bursae
(Does not cover articulating cartilage or intra- articulating discs/menisci
Shapes of synovial joint (6)
Plane - move in one pla Hinge Saddle Condyloid (ellipsoid) Pivot Ball and socket
Plane joints
Two flat surfaces slide against each other
Smooth movement
Single plane
Several direction
Examples
Carpal bones of wrist
Facet joints
Condyloid joints
Atlanto- occipital joint at base of skull
Radiocarpal joints - between radius and the carpals
Saddle joints
Motion in 2 planes at the same time
Degree of sliding
Example:
1st carpometacarpal joint at base of thumb
Hinge joint
Stable flexion and extension
No sliding or deviation
Single plane
Example:
Elbow
Pivot joint
Peg within a ring shaped hole
Rotational motion with gliding
Without bending or sideways displacement
Example:
Atlanto - axial joint - allows head to rotate whilst maintains stability
Ball and socket joint
Stable movement in several directions
Without slippage
Most mobile - least stable
Permit flexion and extension, adduction and abduction, lateral rotation and medial rotation, circumduction
Examples:
Hip
Shoulder
Bursa
Small sac lined by synovial membrane
Contains a thin layer of synovial fluid
Provides cushion between bones and tendons/ muscle around a joint - reduce friction and promotes free movement
Filled with synovial fluid
Communicating or non-communicating with joint cavity
Tendon sheaths
Elongated bursae that wrap around a tendon
Reduce friction associated with the movement of a tendon
Synovial fluid
Clear or pale yellow
Viscous
Slightly alkaline
Contains: hyaluronic acid Lubricin Proteinases Collagenases
Intervertebral discs
Between vertebrae
No synovial membrane
Plexus of arteries
Surround synovial joints
Maintain blood supply regardless of the position
Where do synovial joints form
Between adjacent cartilage models - joint interzone
How do synovial joints form
Chondrocytes at the centre of the interzone region undergo apoptosis - joint cavity
Surrounding mesenchymal cells from the perichondrium form the periosteum where they lie in contact with bone
Form the articulating capsule and supporting ligament which ch lie in contact with the developing joint
Knee joint cartilage
Some cartilage is preserved within the joint and develops into intra articulating ligaments
Examples:
Anterior and posterior cruciate ligaments of the knee
Role of tendon
Force transmission
Role of ligament
Support joints
Restrict range of movement
Hyaline cartilage
Smooth
Reduces friction
Fibrocartilage
Higher collagen content
shock absorption
Increase congruity- better shape
Hydroxyapatite
Calcium Phosphate (CaPO4)
Mineralises extracellular matrix
Makes bone rigid
Compressive strength
Bone made of
Collagen - tensile strength Elastin Water Glycosaminoglycans Proteoglycans
Factors influencing range of motion of a joint
Structure of articulating bone Strength and tension of the ligaments Tone of muscle Apposition of neighbouring soft tissue Hormones (relaxin) Disuse
