Form And Actoins At Joints

Question 1

What are the anatomical levers, fulcrums, applied force, and load

Answer 1

Bones = levers
Joint = fulcrum
Muscle contraction = applied force
External/internal (weight/body weight) = load

Question 2

Outline a class one lever

Answer 2

The fulcrum is in between the applied force and the load (Neck extension at the atlanto occipital joint)

Question 3

Outline a class 2 lever

Answer 3

the load is in between the fulcrum and the applied force (plantar flex action at the ankle joint)

Question 4

Outline a class 3 lever

Answer 4

The applied force is in between the load and the fulcrum (flexion at the elbow joint)

Question 5

What 3 factors does muscle form depend on

Answer 5

Length, number, and arrangement of muscle fibres

Question 6

What effect does the length of muscle fibre have on muscle form

Answer 6

Fibres shorten up to 50% of resting length hence longer fibres allow large range of movement

Question 7

What effect does the number of muscle fibres have on muscle form

Answer 7

Tension is proportional to cross sectional area, hence greater number of fibres increase cross sectional area and results in greater tension

Question 8

What affect does the arrangement of muscle fibres have on muscle form

Answer 8

Parallel arrangement allows greater fibre length thus greater range of movement
Pennate arrangement allows more fibres into the same space thus increasing muscle tension - however range of movement is decreased as maximum contraction is 50% of shortest fibres resting length

Question 9

What are the 3 types of muscle action

Answer 9

Concentric
Eccentric
Isometric

Question 10

What is concentric action

Answer 10

Muscle is active, develops tension, tension greater than load, muscle shortens, joint angle decreases

Question 11

What is eccentric action

Answer 11

Muscle is active, develops tension, load is greater than tension, muscles elongate, joint angle increases

Question 12

What is isometric action

Answer 12

Muscle is active, develops tension, tension is equal to load, no change in muscle length, no change in joint angle

Question 13

What are the 4 difference roles a muscle can have at a joint

Answer 13

Agonist
Antagonist
Stabiliser
Neutraliser

Question 14

What are agonistic and antagonistic roles

Answer 14

Agonistic - prime joint mover acting concentrically to decrease joint angle
Antagonistic - acts eccentrically to oppose and control the movement

Question 15

What is a stabiliser role

Answer 15

Stabiliser - Isomeric action of a muscle(s) to hold a joint still

Question 16

What is a neutraliser role

Answer 16

Neutraliser - muscle eliminates an unwanted movement caused by another muscle
E.g. pronation muscles neutralise supinating effect of flexion biceps brachii

Question 17

What are the concentric actions of muscles, and for which joint do they not apply

Answer 17

Anterior - flexion
Posterior - extension
Medial - adduction
Lateral - abduction

Does not apply for knee joint

Question 18

What is the biceps brachii

Answer 18

Origin is the scapular, insertion at radial tuberosity
Provides flexion at both shoulder and elbow
Provides supination at radioulnar joints

Question 19

What is the triceps brachii

Answer 19

Connected to humerus and scapula, as well as ulna
Provides extension at both the elbow and the shoulder

Question 20

What is the deltoid

Answer 20

Attached to the pectoral girdle (clavicle and scapula)
Attached to the diaphysis of the humerus
Enables flexion (anterior fibres), abduction (lateral fibres), and extension (posterior fibres)

Question 21

What is the lliopsoas

Answer 21

Connected to vertebrae, ilium, and anterior of femur
Enables hip flexion

Question 22

What is gluteus maximus

Answer 22

Connected to hip, sacrum, coccyx, and posterior of the femur
Enables extension of the hip

Question 23

Quadriceps femoris

Answer 23

Group of 4 muscles of the quads
Most superficial is rectus femoris (connects to anterior inferior iliac spine of ilium, and tibial tuberosity via patella and patellar ligament )
Deep component are vasti muscles
Allows knee extension, hip flexion

Question 24

Hamstrings

Answer 24

Grouped muscles (biceps femoris, semi membranosus, semi tendinosus)
Allows hip extension
Allows knee flexion, and rotation when knee flexed

Question 25

What is tibialis anterior

Answer 25

Connects at tibial tuberosity and medial metatarsal
Allows ankle dosiflexion
Allows foot inversion

Question 26

What is triceps surae

Answer 26

Grouped muscle. Most superficial - gastrocnemius. Deep - Soleus
Origin - posterior distal femur. Insertion - Achilles tendon,calcaneus (heel bone)
Allows ankle plantarflexion