Skeletal muscle Flashcards
muscles attach via:
tendons
types of attachment to bone: and eg
origin: attach to stationary bone
insertion: attach to moveable bone
Brachii muscle originates: mid humerus, inserts into ulna over elbow
types of contraction:
isotonic: muscle changes length
- concentric (shortens)
- eccentric (lengthens)
isometric: no change in length
concentric eg:
c. contraction
picking up book
eccentric eg:
lowering book
isometric eg:
holding book steady straight arm forwards
list parts of lever system:
Lever, Fulcrum, Effort, Load
Lever:
rigid structure that moves around fixed point
Fulcrum:
fixed point lever moves around
Effort:
force which causes movement
Load:
(resistance), a force which opposes movement
general eg of lever system:
lever- bone
fulcrum- joint
effort- muscles
load- internal/ external (gym weight)
mechanical advantage:
L closer to F
E further from F
mechanical disadvantage:
L farther from F
E closer to Fulcrum
first class lever: adv/disadv? common?
Effort-Fulcrum-Load
both disadv/adv
not common
second class lever: adv/disadv? common?
Fulcrum-Load-Effort
always mechanical adv.
not common
third class lever: adv/disadv? common?
Fulcrum-Effort-Load
always mechanical disadv.
predominant due to greater range in the body
list classification of fascicles:
parallel, fusiform, circular, triangular, pennate
fascicle features: parallel
fascicles nearly parallel to long axis of muscle, flat tendons on either end
strap muscle
fascicle features: fusiform
f. nearly parallel to long axis of muscle, wide belly and tapers near ends -> tendons
fascicle features: circular
concentric circular arrangements, form sphincter muscles, enclose orifice
fascicle features: triangular
fascicles spread over broad area, converge at thick central tendon, triangle shape
parallel eg.
sartorius muscle
fusiform eg.
digastric muscle
circular eg.
orbicularis oculi muscle
triangular eg.
pectoralis major muscle
fascicle features: and list types pennate
short fascicles in relation to muscle length, tendon extends nearly whole length of muscle
- unipennate
- bipennate
- multipennate
features: unipennate and eg
fascicles arranged on only one side of tendon
intercostals
features: bipennate and eg
fascicles on both sides of central tendon
rectus femoris muscle
features: multipennate and eg
fascicles attached obliquely from many directions -> several tendons
deltoid muscle
prime mover:
agonist, muscle producing movement
antagonist:
opposite movement to agonist
synergist:
neutralises extra motion from agonist, stabilises intermediate joints, less effort for movement
fixators:
stabilise origin of agonist
compartments:
group of muscles with common function together with associated neurovascular components
fascial expression: muscles (if needed), nerve/s (if needed)/ general location/ function
fascial nerve, FOR facial expression
around eyes, forehead, nose, mouth, cheek, chin, neck
mastication: muscles (if needed), nerve/s (if needed)/ general location/ function
trigeminal nerve (mandibular division), FOR mastication (chewing)
temporal area, side jaw near ear, in btw. mouth, around mouth
abdomen: muscles (if needed) and nerve/s (if needed)
thoracic spinal n nerves,
FOR flexion of trunk
connected by rectus sheath (ct., aponeurosis btw)
- rectus abdominis: 6 pack
- external oblique: (external layer, down diagonal towards midline) side of r.a
- internal oblique: (middle layer, upward medial) under ext. oblique
- transversus abdominis: (inner layer, horizontal) under int. oblique
respiration: muscles (if needed), nerve/s (if needed)/ general location/ function
respiration, external/internal intercostals (btw. ribs) elevate ribs
FOR respiration
diaphragm:
- innervated by phrenic nerve
- flattens when breath in (increase thoracic cavity vol.)
- openings for oesophagus, inferior vena cava, aorta
back: muscles (if needed), nerve/s (if needed)/ general location/ function
cervical, thoracic, lumbar spinal nn.
FOR erection of spine, posture
erector spinae: muscle either side of vertebrae
pectoral girdle and thorax: muscles (if needed), nerve/s (if needed)/ general location/ function
pectoralis major: pecs
deltoid: shoulder muscle
trapezius: 2x triangular shape muscle, neck/upper back
anterior compartment of the arm: muscles (if needed), nerve/s (if needed)/ general location/ function
(upper limb), musculocutenous nerve (both muscle and skin of ant. comp.)
FOR flexion
- biceps brachii
(long/short head- laterally/ medially)
posterior compartment of the arm: muscles (if needed), nerve/s (if needed)/ general location/ function
(upper limb), radial nerve
FOR extension
- triceps brachii (lateral/long/medial head- outside/upper inside/lower inside)
anterior compartment of the forearm: muscles (if needed), nerve/s (if needed)/ general location/ function
(upper limb) median and ulnar nerve
FOR flexion of wrist and fingers
hand: muscles (if needed), nerve/s (if needed)/ general location/ function
ulnar and median nn.
FOR fine movement of fingers, precision grip
- thenar eminence (thumb muscles)
- hypothenar eminence (pinky muscles)
gluteal region: muscles (if needed), nerve/s (if needed)/ general location/ function
(superficial, lower limb)
FOR lateral rotation of thigh
- gluteus medius (middle layer)
- gluteus maximus (superficial)
- gluteus minimus (deep)
anterior compartment of thigh: muscles (if needed), nerve/s (if needed)/ general location/ function
(lower limb), femoral nerve
FOR extension of knee (opposite to anterior of arm)
- quadraceps
medial compartment of thigh: muscles (if needed), nerve/s (if needed)/ general location/ function
(inner thigh) obturator nerve
FOR adduction of the hip
posterior compartment of thigh: muscles (if needed), nerve/s (if needed)/ general location/ function
tibial and common fibular (from sciatic) nn.
- hamstrings
FOR extension of hip, flex knee
anterior compartment of leg: muscles (if needed), nerve/s (if needed)/ general location/ function
(lower limb), deep fibular (peroneal) nerve
FOR dorsiflexion of ankle joint
lateral compartment of leg: muscles (if needed), nerve/s (if needed)/ general location/ function
(lower limb), superficial fibular (peroneal) nerve
FOR eversion of foot
posterior compartment of leg: muscles (if needed), nerve/s (if needed)/ general location/ function
tibial nerve (calf)
FOR plantar flexion
- calcaneal tendon (‘achilles’)
