Lecture 1- Introduction Flashcards
3 major components of the MSK
bone
muscle
connective tissue
are all skeletal muscles voluntary
no- postural
function of bone
- Support
- Protection
◦Skull
◦Sternum
• Metabolic
◦Calcium and phosphate
• Storage
◦Calcium, phosphate and fat
- Movement
- Haematopoiesis
◦In adults
◦In babies liver and spleens
function of skeletal muscle
- Locomotion
- Posture
- Metabolic
- Store glycogen
- Venous return
- Deep veins in the legs
- Pumps blood back up to the heart
- Heat production
- E.g. shivering
- Continence
- Constant contraction of urethra and anus
function of conenctive tissue
- Tendons
- Force transmission muscle-bone
- High amounts of collagen, less elastin
- Stability of joints
- Force transmission muscle-bone
- Ligaments
- Support bone-bone
- Fascia (sheets of connective tissue) ◦Compartmentalisation ◦Protection
- E.g. deep fasica
- E.g. think of when we skinned the limbs
- Cartilage
- Articular
- Hyaline
- Very well hydrated
- Slippy
- Blue in colour
- Decrease friction
- Fibrocartilage
- Shock absorption
- Between the vertebra
- In the knee
- Increase bony congruity
- Synovial membrane
- Secretes synovial
- Bursa
- Synovial fluid-filled sacs to protect tendons, ligaments etc from friction
tendon
Force transmission muscle-bone
‣ High amounts of collagen, less elastin
‣ Stability of joints
ligaments
supports bone to bone
fascia
◦Compartmentalisation ◦Protection
‣ E.g. deep fasica
◦E.g. think of when we skinned the limbs
cartilage: articular
Hyaline
• Very well hydrated
- Slippy
- Blue in colour
‣ Decrease friction
cartilage: fibrocartilage
Shock absorption
Between the vertebra
In the knee
‣ Increase bony congruity
synovial membrane
secrete synovial fluid
bursa
synovial fluid- filled sacs to protect tendons, ligaments etc friction
bone connective tissue
ECM- fibres and ground substance
- In bone calcified - CaPO4(gives bone strength)
Bone is dense connective tissue
- Osteocytes
- Osteoblasts
- Osteoclasts
osteoblasts
lay down osteoid and build bone
how do osteoblasts build bone
Lay down bone and step back, lay down bone and step back
Traps osteoblasts in osteoid that is calcified—> osteocytes (trapped osteoblast in lacunae
osteocytes communicate via
via cytoplasmic processes (think cannuculi )
◦Transmit signals
osteocytes are important for
sensing stresses and strains in the bone
◦Will cause growth
◦Why exercise helps build bone
osteoblasts
◦Multinucleated
◦Related to macrophages
◦Release acidic substances and dissolve the bone —> releasing calcium
cortical bone strucutre (compact bone)
◦A bunch of pencils being held together ◦Haversion and volkmanns canals
classification of bone
long
short
flat
sesamoid
irregular
long bone
◦Bone longer than wide
◦Very good lever
◦Humerus
short
◦Bone as long as wide
◦Tarsals
◦Work together to give a range of movement
◦Gives points of attachment to for ligaments and tendons
flat
intramembranous ossification
◦For protection
◦Skull
◦Sternum
sesmoid
◦Protects tendons
◦E.g. patella
◦Shaped like a sesame seed
irregular
vetebra
bony prominences- muscle attachments
Areas where bones are close to the surface (called “bony prominences”) and areas that are under the most pressure are at greatest risk for developing pressure sores.
body prominences size
- Their size tells us about the muscle that attaches to it
- Small- not a powerful muscle that attaches
- If big site- must be a powerful muscle that attaches
grooves
related to nerves
- impression on bones- no free space in body
bone blood supply
each bone has multiple blood supply
Depending of let right dominance, bone will be
thicker in dominant arm/ leg • very dynamic
◦Due to osteoclasts and blasts
joints
Connects one bone to another
- Great variation in range of movement
- Highest risk of dislocation
- Range of movement versus stability
classification of joint
- fibrous
- cartilaginous
- synovial joints
fibrous joints
◦Two bones glued to eachother using collagen
◦Won’t move very much
◦For areas that need great stability and strands
e.g. teeth and skull
cartilaginous joint
◦Glue is cartilage (more flexib;e than pure collagen fibres)
‣ Limited mobility (more than fibrous)
‣ Found at end of growing bones or along the midline of the body
◦Sites of growth e.g. epiphyseal plate
synovial joint
◦Separates bones are capped by smooth articulate cartilage with a thin film of synovial fluid
separating them
‣ Secreted by synovial membrane
◦Like egg white ◦Frequently highly mobile ◦Found all over the skeleton
classification of synovial joints
plane joint
hinge joint
pivot
saddle
condyloid
ball and socket
plane joint
Two flat surfaces sliding over eachother
‣ E.g. in the foot (tarsals)
hinge
◦Moving in a single plane
◦E.g. elbow
pivot
rotational
saddle
◦Between thumb and carpal ◦Constrained motion
◦Two different planes of movement
condyloid
◦In the wrist
◦Eclipse shaped joint
◦Alllows flexion and extension
◦No rotation of the the wrist
ball and socket
◦Hip and shoulder
◦Round head of femur moving into another joint
◦Allows movement in many planes
development of synovial joints using knee as an example
Arise form cartilage models of bone (hyaline)
1) Where joints form a load of chondrocytes die and leave a gap
2) Perichodnrium remains and forms the capsule of the joint and contributes to
joints as levers
- first-class lever
- second-class lever
- third-class lever
Mechanical advantage
Ardvark long olecranon
- On the right
- For strength for digging
Sloth- short olecranon
- Don’t need as much strength
The origin is usually the
stationary proximal anchord pointt
The insertion is usually the
mobile distal attachment point
characteristic of muscle contractin
Muscle contraction is symmetrical exerting equal force on origin and insertion
muscles can only
PULL
THEY CANNOT PUSH
Muscles can onyl act on the
joints they cross
the action of a muscle on a joint is a function of the
orientation of its fibres of those fibres to the joints
muscles work …… and almost never in…
◦Muscle work together and almost NEVER in isolation
‣ CNS coordinates
types of contraction
Concentric concraction
Eccentric contraction
Isometric contraction
Concentric contraction
muscle pull while shortening (e..g bicep curls)
Eccentric contraction
Muncle puls while lengthening (knee extensors walking downhill)
Isometric contraction
muscle pulls while staying same length (carrying a load)
muscles can
1) shortens
2) lengthens
3) stays the same
always pullling
muscles are found within
within fascia (deep) compartments ◦The muscles within a compartment share a common innervation and action (generally)
◦Same nerve supply and blood supply
◦Just need to learn one nerve
types of muscles
parallel
fusiform
sphincter
triangular
pennate
parallel muscle
lengthen and not always that powerful
fusiform
◦Can fit in more muscle fibres
◦More powerful
sphincter
◦Parallel muscle bent into a circle
◦To close things
‣ Eye
‣ Anus
triangular muscle
◦Deltoid
◦Gives more diversity in action
pennate (feather)
Can’t shorten (as much as parallel) much but have loads fo muscle fibres meaning they are very powerful
predicting muscle action
where does it attach?
how many joints does it cross?
how is it related to the joints?
what direction do the fibres run in?
connective tissue are
All physically connected to eachother
Continuity between periosteum, joint capsule, tendon, epimysium and bone collagen matrix
Anatomists and histologists have different names for different things…Superficial fascia=
subcutaneous fat
deep fascia=
epimysium of muscle
name the fascia of the thigh
fascia lataa
- deep dascia
tendons
• parallel collagen fibres connecting muscles to bones
ligaments
- Connects bone to bone
- Develops from perichondrium
- Usually thickening of the connective tissue
- Limit movement
aponeurosis
Flattened tendon (sheet like)
in the head
Abdominal wall (no muscle- richi collagen)
Plantar fascia (plantar aponeurosis)
innervation of joints- Hiltons law
the innervation of joints is the same as the muscle and skin over the sites of insertion
Basic principles of musculoskeletal development- Body segmentation due to which gene
HOX gene
homeostatic mustants 1
• some people have 6 lumbar instead of 5
homeostatic mutant 2
extra-fingers- polydactyl
homeostatic mutant 3
extra cervical rib
–>man compress vessels/ nerves
the power of serial homologus
upper limbs rotate..
out 90 decreases
lower limbs rotates
in 90 degrees
