Muscles Flashcards
Tendon
Muscle to bone
Part of muscular and skeletal system
Origin
Fixed end
Most stationary
Proximal end of muscle
Insertion
Mobile
Distal end of muscle
Undergoes greatest movement
Belly
Part of muscle between origin and insertion
Agonist
Muscle contracting in pair
Antagonist
Muscle relaxing in pair
Synergists
Muscles that work in groups
Each muscle can belong to more than one synergist
Prime mover
Muscle that plays a main role out of the group of synergists
Fixators
within synergists
Stabilise the origin of a prime mover
Muscles grouped into 3 main classes
Pennate
Straight
Orbicular
Pennate muscle
Produces the greatest force Most muscles involved in movement Striated - contracting these directions Bipennate Semipennate Multipennate
Bipennate
Fibres arranged on either side on a common tendon
Barbs on a feather
Semipennate
Or unipennate
Muscle with fibres on one side go the tendon
Multipennate
Muscle fibres arranged at many places around a central tendon
Straight Muscle
Fibres parallel to long axis of the muscle
Orbicular muscle
Fibres arranged in a circle around an opening
Specific muscle shapes
Quadrate Rhomboidal Fusiform Trapezium Triangular
Digastric
Muscles with multiple components such as two bellies
Bicipital
Muscle with two origins
Quadrate muscle
Four sided
Right angles
Rhomboidal muscle
Four sided with no right angle
Fusiform muscle
Spindle shape
Tapered either end
Trapezium muscle
Four sided
no right angles or parallel sides
Triangular muscle
Three sided
Lever systems
Lever - bone
Fulcrum - joint
Weight - force of gravity
Class i, ii and iii
Class I lever
Fulcrum located between pull and the weight
Seesaw
Posterior neck muscles contact to cause neck extension (face is the weight and joint in neck acts as fulcrum)
Class II lever
Weight between fulcrum and the pull
Wheelbarrow
Muscles contract to open jaw (pull) and mandible is weight. TMJ joint is fulcrum
Class III
Most common
Pull located between fulcrum and weight
Biceps brachii contracts to pull the the radius (lever) which flexes the elbow (fulcrum) and elevates hand (weight)
Sternocleidomastoid
Neck - 2
One contracting alone - Laterally flexes head and neck to same side/rotates head to opposite side
Both contract together - Flexes neck
Trapezius
Neck - 1
Extends and laterally flexes neck
Erector spinae group
Superficial back muscles grouped together
Extending, laterally flexing and rotating the vertebral column
Thorax (thoracic cavity)
Rib cage cavity from neck to diaphragm
Thoracic muscles
4 main groups of the thorax muscles: Scalenes External intercostals Internal intercostals Transversus thoracics
Diaphragm
Muscle of the thorax
Major movement produced by quiet breathing
Dome shaped
During contracting, dome flattens and thoracic cavity increases causing inspiration
Inspiration
Rest - Diaphragm contracts and rib cage is elevated by external intercostal muscles
Exercise - Diaphragm contracts and scalene elevates first two ribs more forcefully casing an increase in thoracic volume
Expiration
Rest - Diaphragm relaxes af muscle groups relax
Exercise - Diaphragm relaxes and internal intercostal muscles and transverses thoracis depress the ribs causing a decrease in thoracic cavity volume
Rectus Abdominis
Flexes vertebral column and compresses abdomen
External and internal abdominal oblique
Flex and rotate vertebral column
Compress abdomen
Depress thorax
Transversus abdominis
Compress abdomen
Deltoid (anterior, medial and posterior)
Flexes and extends shoulder
Abducts
Medially and laterally rotates arm
Coracobrachialis
Abducts the arm and flexes the shoulder
Pectoralis major
Flexes shoulder
Adducts
Medially rotates arm
Latissimus dorsi
addicts and medially rotates arm
Extends shoulder
Teres major
Extends shoulder
Adducts arm
Medially rotates arm
Rotator cuff
Hold head of humerus in place at glenoid cavity
Rotator cuff comprised of
Infraspinatus Subscapularis Suprasinatus Teres minor All shoulder movement
Biceps brachii
Arm
Flexes shoulder and elbow
Supinates forearm and gand
Brachialis
Arm
Flexes elbow
Tricep brachii
Arm
Extends elbow
Extends arm
Adducts arm
Brachioradialis
Forearm
Flexes elbow
Pronator teres
Forearm
Pronates forearm
Supinator
Forearm
Supinates forearm
Gluteus maximus
Extends hip
Gluteus medius
Abducts thigh
Gluteus minimus
Abducts though
Piriformis
Abducts thigh
Tensor fasciae latae
Thigh
Flexes hip
Abducts
Medially rotates thigh
Vastus Lateralis
Thigh
Help make up quadriceps
Rectus Femoris
Thigh
Help make up quadriceps
Sartorius
Thigh
Flexes hip and knee
Vastus medialis
Thigh
Help make up quadriceps
Vastus intermedius
Thigh
Help make up quadriceps
Hamstring
Semitendiosus
Semimembranosus
Biceps femoris
Gastrocnemius
Calve (posterior)
Plantar flexes foot and flexes knee
Soleus
Calve (posterior)
Plantar flexes foot
Tibialis anterior
Calve (anterior)
Dorsiflexes foot