What is torque?
Force of rotational movement of bones about a joint
What is a muscle lever arm?
The perpendicular distance from an axis to the line of action of a force?
What is another term for a muscle lever arm?
Moment arm
What does output force require?
Long ‘in’ lever and a short ‘out’ lever
What does output speed require?
Short ‘in’ lever and a long ‘out’ lever
What are the challenges of bipedal locomotion?
Gravity and efficiency
Stability
Where does gravity act on the body?
The centre of mass
Can your centre of mass change with movement?
Yes
With relation to our bodies, what is gravity a product of?
Mass
Acceleration of gravity
Where is the human body’s centre of mass?
Within the pelvis
What is stability of the body determined by?
Base of support
Position of total body centre of mass
What is gait in the simplest of words?
Pattern of interaction of limbs with the ground
What is gait divided into?
Stance phase
Swing phase
What is the definition of gait?
The period from heel strike of one limb until the next time that heel hits the ground
How much of the gait cycle does the stance phase take up?
First 60%
How much of the gait cycle does the swing phase take up?
Remaining 40%
What is the stance phase of the gait cycle?
Heel strike till the toe of the same foot begins to lift off the ground
What is the swing phase of the gait cycle?
Where the limb has lost contact with the ground
What is the difference between running and walking?
Walking has one foot on the ground at all times
Running you have both feet off the ground, at some point
When lowering the forefoot to the ground, what muscles do you use?
Ankle dorsiflexors
What is eccentric contraction?
The motion of an active muscle while it is lengthening under load.
What is concentric contraction?
The motion of an active muscle while it is shortening under load.
What is the main muscle responsible for ankle dorsiflexion during heel strike?
Tibialis anterior
What muscles are responsible for stopping your legs from swinging all the way backwards?
Hip extensors
What is a reverse forward swing in terms of locomotion?
Moving your leg backwards for momentum but decelerating it to avoid doing the splits
What muscles do you use to preserve the longitudinal arch of the foot during the gait cycle?
Intrinsic muscles of foot
Long tendons of foot
What is another term for the loading response of the gait cycle?
Having a flat foot
What muscles accept your body weight during the loading response of the gait cycle?
Knee extensors/Quadriceps
What muscles decelerate your mass in the loading stage of the gait cycle?
Ankle plantarflexors
What are the main ankle plantarflexors in mass deceleration of the gait cycle?
Triceps surae
What muscles stabilise the pelvis in the loading phase of the gait cycle?
Hip abductors
What are the main hip abductors in the gait cycle?
Gluteus medius
Minimus tensor of fascia lata
What muscles are involved in control dorsiflexion of the midstance stage of the gait cycle?
Ankle plantarflexors
What is the point of the control dorsiflexion stage of the midstance stage of the gait cycle?
To preserve momentum
What is the last stage of the stance phase?
Terminal stance
What does the terminal stance of the stance phase look like?
Heel coming off
What is the first stage of the swing phase?
Pre-swing
What does the first stage of the swing phase look like?
Toe coming off
What muscles are used to accelerate mass in pre-swing of the swing phase?
Long flexors of digits
What order does the swing phase occur in?
Pre-swing
Initial swing
Mid-swing
Terminal swing
What things can alter gait?
Ageing
Structural damage
Artritis, inflammatory or degenerative conditions
Footware
What order does the stance phase occur in?
Heel strike
Loading response
Midstance
Terminal stance
What is antalgic gait?
Any gait that reduces loading on the affected extremity
With reference to the gait cycle, how does antalgic gait reduce loading?
Decreasing stance phase time/ joint forces
What are examples of antalgic gait?
Having a stone in your shoe Diabetic foot Osteoartritis Gout Joint/ limb deformity Ingrown toenail General trauma
What is antaxic gait?
Unsteady, uncoordinated walk Wide base Feet thrown out Can't stay steady Similar to drunk people walking
What diseases result in ataxic gait?
Multiple sclerosis
Cerebellar diseases
What is parkinsonian gait?
Involuntary movement with short, accelerating steps which are often on tip toe
Trunk flexed forward
Legs flexed stiffly at the hips and knees
What diseases cause parkinsonian gait?
Parkinson’s disease
Conditions affecting the basal ganglia
What is myopathic gait more commonly known as?
Waddling gait
What is myopathic gait?
When one leg goes into swing phase the opposite leg isn’t stable
What group of diseases tend to cause myopathic gait?
Muscular diseases
What is neuropathic gait more commonly known as?
High stepping gait
What disease can you see neuropathic gait in?
Peripheral nerve disease
What does neuropathic gait look like?
Lifting whole leg up higher than normal to avoid dragging the toe on the ground
What muscles are weak in neuropathic gait?
Foot dorsiflexors
What is a trendelenburg gait?
Pelvis drops when good limb enters swing phase
Pelvis not held level when walking
What is coxa vara?
Decreased angle of the neck of the femoral bone
What is coxa valga?
Increased angle of the neck of the femoral bone?
What is the normal angle of the neck of the femoral bone?
120-140 degrees
What causes a duck waddle gait?
Coxa vara
What is pes planus?
Flat feet
What are the arguments against humans being adapted for bipedalism?
Flat feet
Back pain
What group of individuals are particularly prone to flat feet?
Overweight people who stand for long periods of time
What signals are responsible for the form of the skeleton?
Genetic
Functional
What are functional signals?
Signals occurring after birth to which developing bone responds
Which embryological structures is bone derived from?
Neural crest
Mesoderm
What is the process by which most bone develops?
Intra-membranous ossification
What is another term for endochondral ossification?
Intrachondral ossification
In bone development, which genes are responsible for specifying the identity of the different vertebral segments?
HOX gene
True or false? The base of the skull develops via calcification?
False - The base develops from somites
What bones develop via intra-membranous ossification?
Flat bones of skull
Mandible
Clavicle
How does intra-membranous ossification work?
Mesenchyme cells change to osteogenic cells and then osteoblasts
Between endochondral and intramembranous ossification, which process involves cartilage.
Endochondral
How does intra-chondral ossification work?
Cartilage gets vascularised and dies
Calcium is deposited
Osteoblasts and osteoclasts develop
What bones does endochrondral ossification form?
Most bones in the body, mainly long bones.
Where are the genes that determine the shape and length of the fingers?
Progress zone
What shape is the hand before fingers are formed?
Paddle-shaped
What happens in development to form hands?
Cells between the fingers die
What are the different parts of bone?
Epiphysis
Physis
Metaphysis
Diaphysis
What is the another term for physis?
Epiphyseal (growth) plate
What is the difference between cartilage and bone?
Bone is vascularised, cartilage is not.
True or false? Bone is a connective tissue?
True
What is the difference between chondroblasts and chondrocytes?
Chondroblasts become chondrocytes when they are surrounded by ECM
What is the purpose of chrondroblasts in bone?
Cartilage formation
What is the purpose of an extracellular matrix (ECM) in bone?
Fibres and ground substance production
Give an example of a fibre found in bone?
Collagen
If cartilage is avascular, how does it recieve nutrients?
Diffusion
What is apositional growth?
The onion-like increase in size
What are the characteristics of apositional growth?
Epiphyseal growth
Growth in length
Growth in diameter
What is the difference between cancellous bone and compact bone?
Compact consists of densely packed osteons
Cancellous bone has a honeycomb like structure
What are other terms for cancellous bone?
Trabeculae
Spongy bone
Cancellous bone
Does bone have a more similar structure to dermal or nervous tissue?
Nervous
Which bone cell is responsible for bone deposition?
Osteoblasts
Which bone cell is responsible for bone resorption?
Osteoclasts
Which bone cell is multi-nucleate?
Osteoclasts
Which joints don’t move?
Synarthroses
Which joints can move freely?
Diartroses
Which joint is a well known diarthroses?
Synovial joint
What is the definition of an amphiarthroses?
A slightly movable joint
How does trabecular bone adapt to load?
Develops complementary to where load is coming from
What are the stages of bone healing?
- Haematoma
- Subperiosteal & endosteal cell proliferation
- Callus- woven bone
- Consolidation
- Remodelling
What bone cells are key to bone remodelling?
Osteoblasts
Osteoclasts
What percentage of spongey bone is inorganic?
60%
What contributes to the organic part of spongy bone?
Type 1 collagen
Non-collagenous proteins
What is the difference between bone and osteoid?
Osteoid is unmineralised bone
What is the cycle of bone remodelling?
Quiescence Resorption Reversal Formation Mineralisation Quiescence
How long does bone remodelling take?
Months
What is the name of vitamin D’s active form?
1, 25 Vitamin D 3
What does the perimysium surround?
Between 10-200 muscle fibres
What does endomysium contain?
Myofibrils
What does perimysium separate into?
Fascicles
What are myofibrils surrounded by?
Sarcolemma membrane
Where is the sarcoplasmic reticulum?
Around the sarcolemma membrane
What does the I band of the sarcomere represent?
Actin filament
What does the A band of the sarcomere represent?
Actin and myosin
What does the H band of the sarcomere represent?
Myosin filaments
What is titin?
A protein which anchors myosin to the Z line
What is nebulin?
A protein which extends the length of actin and determines its length during assembly
What is the difference between chimpanzee and human bipedalism?
Chimpanzees move bipedally using ‘bent knee bent hip’…
What is the purpose of the iliofemoral ligament in balancing?
Preventing the trunk rotating backwards at the hip
What is the purpose of the cruciate ligaments in balancing?
Helping keep the upper body and thigh from falling forwards at the knee
Where do the vertebral curves pass weight to?
The lower limb
What is the difference between the femur in humans and in apes?
The femoral head in humans is larger and its diagonal disposition makes the femur more stable.
How is the knee joint stabilised?
Soft tissues; posterior and anterior cruciate ligaments and the medial and lateral collateral ligaments
What is the ‘locking mechanism’
Associated with the knee enabling it to stabilise in a fully extended position
What type of arch do primates have in their feet?
Transverse
What type of arch do humans have in their feet?
Two-part longitudinal
What are the parts of the longitudinal arch in the feet of humans?
Medial
Lateral
Why is the arch in humans important?
Medial weight transfer during mid-stance; shock absorber; better weight distribution while standing.
Where is the human body’s centre of mass?
Within the pelvis anterior to S2
How is stability of a body determined?
The relationship between the base of support and the position of the total body centre of mass
True or false? Bones are vascular?
True