Week 4 Flashcards
the shape of the muscle detemines function depending on:
- length
- number of fibres
- arrangement
state 2 facts about the length of muscle fibres:
- they shorten upt to 50% at resting length
- large range of motion = long muscle fibres
what does CSA mean in relatipon to number of muscle fribres?
cross sectional area measures the number of fibres
how does CSA effect tension?
- tension (force) is proportional to cross sectional area
- more fibres = greater CSA = greater tension
how does arrangement of fibres effect function?
- the way they are arranged means they can fit more fibres into the same space (which means more force) = more efficient.
what are parralllel fibres?
fibres arranged veritcally between tendons
what are prennate fibres?
fibre that are slanting diagonal so that more fibres fit
- reduced shortening but greater CSA
what are the anatomical levers and what do they do?
- bones - lever
- joints - pivot or fulcrum
- muscle contraction - pull
- load - external or internal (eg. lifting something or weight of skull)
in types of levers with muscle attachement _________ determines the function
lever arrangement
what are the 3 classes of levers?
first - stabilise joint position
eg. neck extentsion at the alanto - occipital joint
second - effective at overcoming loads
eg. plantarflexion at the ankle joint
third - long muscle, large range of movement + speed
eg. flexion at the elbow joint.
what are the 3 ttypes of muscle action?
concentric
eccentric
isometric
what are the qualities of concentric muscle action?
- muscle is active, develops tension
- change in joint position
- shortening of the muscle
(using/moving the muscle)
what are the qualities of eccentric muscle action?
- muscle is active, develops tension
- change in joint position
- lengthening of muscle
(controlled release)
what are the qualities of isometric muscle action?
- equal/stays the same/maintains
- muscle is active, develops tension
- NO change in joint position
- NO change in length of muscle
what are the 4 types of muscle roles?
agonist
antagonist
stabiliser
nuetraliser
what are the roles of agonists and antagonists?
agonists act concetrically (bicep shortens)
antagonists act eccentrically to counterbalance (triceps brachii lengthens to stop flexing too fast)
what is the role of stabilisers?
- when a muscle is active to hold a joint still (eg. holding book)
eg. biceps brachii role is a stabiliser and its action is isometric as there is n change in length.
what is the role of a nuetraliser?
- muscle eliminates an unwanted movement caused by another muscle.
eg. drinking from a glass - flexion yes, supination no, so pronator muscles nuetralise supinating effect of biceps brachii.
what are the rules of concentric muscle actions?
- the muscle that is anterior to the joint produces flexion
- the muscle posterior to the joint produces extension
- the muscle lateral to the joint produces abduction
- muscle medial to the joint produces adduction
* this applies to all joints except for the knee.
* * there is NO adduction muscles in HUBS 191 (other than ligaments) and only 1 abductor.
Tell me about the Deltoid (6)
- coming from clavicle + scapular
- attaches to lateral shaft of the humerous
- flexion (anterior fibres)
- abduction (lateral fibres)
- extension (posterior fibres)
- attaches to pectoral girdle
Tell me about the Biceps brachii (4)
- shoulder (flexion)
- elbow (flexion)
- radioulna joint (supination)
- attaches to the scapular and radius
Tell me about the Triceps brachii (3)
- shoulder (extension)
- elbow (extension)
- crosses over shoulder and elbow joints
Tell me about the Iliopsoas (3)
- hip (flexion)
- ilialus + psoas major insert/weave together to cross hip joint and insert in fermur
- anterior to hip
Tell me about Gluteus maximus (2)
- hip (extension)
- attachment to femur + large tendon
Tell me about Quadriceps femoris (3)
- made of 4 muscles
(rectus femoris, vasti muscles - lateralis, intermedius, medialus) - all 4 cross anteriorly over the knee to produce extension
- ONLY case where a muscle crossing anteriorly will produce extension
What are the vasti muscles?
3/4 of the Quadriceps femoris thigh muscles:
lateralis - outer
intermedius - middle
medialus - inner
cross anteriorly across knee to produce extension
tell me about rectus femoris:
1/4 of the quadriceps femoris
- superficial
- crosses anteriorly over hip
- extension of the knee
Tell me about the Hamstrings (4)
- hip (extension)
- cross posteriorly over hip (helping gluteus maximus extend hip)
- crosses posteriorly over the knee (flexion and rotation of knee when flexed)
- made up of bicpes femoris, semi mebranosus, semi tendinosus.
what muscles are the hamstrings made of and what do they do?
biceps femoris - lateral knee flexion, hip extension
semi membranosus - inserts medially to leg
semi tendinosus
Tell me about Tibialis anterior (4)
- ankle dorsiflexion
- foot inversion
- does NOT cross over knee, only ankle and foot
- starts laterally, then moves to medial
Tell me about Triceps surae (3)
- calf muscles
- gastrocnemius: through knee, inserts into foot, plantar flexion, flexion of the knee.
- soleus: through ankle only, plantarflexion
The aspects of ___ that muscle crosses through:
The aspects of the join that the muscle crosses through infuence movement.
standing and gait require:
complex movement and lower limb standing with minimal energy expedicture.
quadrapedal?
- good base support
- demands lots of energy
bipedal? (3)
- small area of contact with ground to support, insufficient size to provide full balance
- plantar surface of feet
- energy efficient because of ligaments, most muscle energy used to stay upright in ankles.
- requires special anatomical features to stay upright
what does gravity mean for the body?
- acts as a agonistor antagonist
- helps create movement, but also struggle for muscles moving in the opposite direction of it
- to be stable/upright, anatomical solutions are needed.
what are the qualities of the hip joint?
- the gravity line is posterior to the joint which means when standing upright, ligaments are tight and we are actually pushing hip into extension
- is a joint that can be locked by ligaments
what is the difference in ligament and muscles as far as energy expediture goes?
muscles require energy to stay still, ligaments dont.
what are the movements of ligaments in the hip joint?
- hip in flexion: lax anteriorly, taut posteriorly
- hip in extension: taut anteriorly, lax posteriorly
what are the attributes and movements of the knee joint?
- line of gravity is anterior to joint
- joint is pushed into extension when standing
- extension = ligaments are tight, joint is locked
what are the attributes and movements of the ankle joint?
- gravity is anterior to joint
- gravity and the fact that the line of gravity is mostly lying anteior to the body means that the body falls forward into dorsiflexion. the ankle joint does not lock and has to use plantarflexor muscles to stabilise + counterbalance.
- bc of this muscles get tired from holding body’s weight, energy is consumed.
what is the bipedal gait cycle and what does it involve?
- it is a learned moveemnt stratergy
- includes stance and swing phases
- includes heel strike and toe off phases
right leg ^_^
left leg ^
(^swing _stance) - gait is dynamic (continuous sequence)
Tell me about the EARLY STANCE (heel strike):
HIP: flexion moving to extension. Concentric activity of gluteus maximus + hamstrings. Eccentric activity of the ilipsoas
KNEE: extension (locked for stability). Isometric activity of quadriceps femoris + hamstrings + gastrocnemius
ANKLE: dorsiflexion (tibialus anterior), moving to plantarflexion. Stable, best bony congruence. Concentric activity of triceps surae, eccentric activity of tibialis anterior to control rate of foot drop to the ground.
Tell me about MID STANCE:
Starts to use more energy
HIP: moving into extension. Concentric acivtiy of gluteus maximus + hamstrings. Eccentric activity of iliopsoas.
KNEE: stays locked in extension, moving slightly to flexion. Concentric activity of hamstrings + gastrocnemius.
ANKLE: moving into plantarflexion. Gravity + gastrocnemius + soleus plantarflexing, tibialus anterior counteracts this large force.
Tell me about LATE STANCE (toe off):
HIP: extension. Eccentric activity of ilipsoas. Concentric activity of gluteus maximus + hamstrings
KNEE: extension. Concentric activity of hamstrings + gastrocnemius
ANKLE: full plantarflexion. Concentric activity of triceps surae (strong for propulsion of toe)
Tell me about EARLY SWING:
HIP: moving into flexion. Concentric activity of ilipsoas. Eccentric activity of gluteus maximus + hamstrings (controls rate of swing)
KNEE: in flexion. Concentric activity of hamstrings + gastrocnemius.
ANKLE: dorsiflexion (to allow for toes to clear the ground during swing). Concentric activity of the tibialis anterior.
Tell me about MID SWING:
HIP: flexion. Concentric activity of iliopsoas. Eccentric activity of the gluteus maxiumus and hamstrings (to control rate of swing).
KNEE: flexion. Concentric activity of the hamstrongs + gastrocnemius.
ANKLE: dorsiflexion (to allow clearance of toes). Concentric activity of tibialus anterior.
Tell me about LATE SWING:
HIP: flexion. Concentric activity of iliopsoas. Eccentric activity of gluteus maximus + hamstrings (to control rate of swing).
KNEE: flexion but moving to extension to prepare for heelstrike. Knee lock, stability. Concentric activity of quadriceps femoris.
ANKLE: dorsiflexion (for most stable position for heel strike). Concentric activity of tibialis anterior. Isometric activity of triceps surae and keep ankle stable.
what are 2 things that influence joint position?
line of gravity and soft tissues.
what is the difference between sample + population?
population is the whole, sample is a small representative part of the pop.
what is the purpose of a sample?
helps you make inferences about the population. it is too costly + difficult investigate whole pop.
how to find percentage?
% = 100% x no./total
how to find proportion? what is it between?
no./total no.
between 0 - 1.0
why is it better to have a larger sample size?
it means more certainty and a more accurate depiction of the population.
what are the 2 types of variables? + eg.s
- catergorical - binary eg. colour of m&ms, eyecolour, type of bone fracture, stage of cancer.
- continuous - average eg. height, age, weight.
how to calculate measn/average:
sum of all observations/ number of observations.
explain why taking a more samples is good with continuous variables?
then you can take more averages from the whole population through the different samples which when put together will narrow the standard deviation and show the true mean more certainly.
how is the standard deviation narrowed when using continuous variables?
by making the sample size larger so that true mean is clearer.
how do we present samples?
summarise in tables/graphs
if catagoral: present proportions/percentages
if continuous: present where the mean/average (central tendancy) is and how spread out the data is (standard deviation)
what is standard deviation?
how far away each data point is from the mean, and the average distance from the mean is the standard deviation.
