Musculoskeletal system: form and action at joints Flashcards
explain a class 1 lever
fulcrum is between force and load
stabilizes joint position
-a see-saw
-neck extension at atlanto-occipital joint
explain a class 2 lever
load is between fulcrum and force
effective at overcoming heavy loads
-a wheelbarrow
-plantar flexion at the ankle joint
explain a class 3 lever
force is between fulcrum and load
large range of movement and speed
-tweezers
-flexion at the elbow jointf
3 factors that determine muscle function
- length of muscle fibers
- number of muscle fibres
- arrangement of fibers
3 types of muscle action
- concentric
- eccentric
- isometric
explain concentric movement
muscle shortens and the angle decreases
tension is greater than the load
change in joint position, the muscle is active and develops tension
explain eccentric movement
muscle elongates by being pulled by another muscle or gravity in the opposite direction and the angle increases
tension is lesser than the load
change in joint position, the muscle is active and develops tension
explain isometric movement
there is no change in joint position or length of muscle
muscles are active and develops tension BUT tension is equal to the load
4 roles of the muscles
- agonist: creates movement
- antagonist: opposes or controls movement
- stabilizer: holds joint still
- neutralizer: stops unwanted movement
explain agonist and antagonist roles
agonist: acts concentrically to create movement at the joint
eg: flexion at the elbow
- biceps brachii shortens
antagonist: acts eccentrically to oppose and control the movement
- triceps brachii lengthens
explain stabilizers roles
holds the joint still and prevents movement at joint
eg: holding a heavy book
- biceps brachii acts as a stabilizer and is isometric
explain neutralizers roles
eliminates an unwanted movement caused by another muscle
eg: trying to drink from a glass
-biceps brachii can flex the elbow and supinate however when drinking from a glass you dont want the arm to supinate
-pronator muscles in the forearm acts as a neutralizer
bicep brachii - origin
scapula
bicep brachii - insertion
radial tuberosity
bicep brachii - movement
shoulder: flexion
elbow: flexion
radioulnar joints: supination
triceps brachii - origin
scapula and humerus
triceps brachii - insertion
olecranon process of ulna
triceps brachii - movement
shoulder: extension
elbow: extension
deltoid - origin
scapula and clavicle
deltoid - insertion
deltoid tuberosity
deltoid - movement
shoulder movement
- flexion: anterior fibers
- abduction: lateral fibers
- extensions: posterior fibers
iliopsoas - the 2 sections
iliacus and psoas major
iliopsoas - origin
iliacus - iliac fossa
psoas major - lumbar vertebrae
iliopsoas - insertion
femur
iliopsoas - movement
hip - flexion
gluteus maximus - origin
ilium and sacrum
gluteus maximus - insertion
femur
gluteus maximus - movement
hip - extension
quadriceps femoris - the 4 sections
- rectus femoris
the vastus muscles - lateralis
- intermedius
- medialis
quadriceps femoris - origin
ilium - rectus femoris
femur - vastus muscles
quadriceps femoris - insertion
tibial tuberosity
quadriceps femoris - movement
hip - flexion (only rectus femoris)
knee - extension
hamstrings - 3 sections
- bicep femoris
- semimembranosus
- semitendinosus
hamstrings - origin
ischium
- long head of bicep femoris
- semimembranosus
- semitendinosus
femur
- short head of bicep femoris
hamstrings - insertion
tibia
- semimembranosus
- semitendinosus
fibula
- bicep femoris
hamstrings - movement
hip - extension
knee - flexion and rotation (when knee is flexed)
tibialis anterior - origin
tibia
tibialis anterior - insertion
tarsals
tibialis anterior - movement
ankle - dorsiflexion
triceps surae - 2 sections
- gastrocnemius (2 heads)
- soleus
triceps surae - origin
gastrocnemius - condyles of femur
soleus - tibia and fibula
triceps surae - insertion
calcaneus via calcaneal (Achilles tendon)
triceps surae - movement
knee - flexion (gastrocnemius only)
ankle - plantarflexion
