Muscles Flashcards
What are the three major parts of muscles?
1) HEAD (caput): at the origin
2) BELLY (ventrer): active muscle
3) TAIL (cauda): passive; at the insertion
What are the two major parts that each muscle has?
1) ORIGIN (origo)
2) INSERTION (insertio)
Where is the origin of the muscle usually located?
at the proximal end of the muscle (the one closest to the body axis)
What are the different types of muscles?
spindle shaped muscles
wide muscles
two headed muscles
three headed muscles
four headed muscles
two bellied muscles
circular muscles
sphincter muscles
What are “synergistic muscles”?
When two muscles work together
What are muscles called when they work together?
synergistic muscles
What are muscles called when they work against each other
antagonistic muscles
What is the fixed point? In Latin?
- punctum fixum
- every point that remains immobile (due to its attachment to the trunk)
What is “muscle tonus”?
the minimal amount of tension that every muscle is under.
What does anaesthesia invoke? (what type of -tonus?)
hypotonus
What are the two types of contractions?
isometric and isotonic
What is an isotonic contraction?
at a certain tention, the muscle slowly begins to contract and shorten
What is an isometric contraction?
continual increase in muscle tension without a change in muscle length
How can muscles be categorized?
- depending on the number of joints they act upon
- depending on the functional effects they have on joints
How are muscles categorized depending on the number of joints they act upon
- uniarticular muscle
- biarticular muscle
- polyarticular muscle
How are muscles categorized depending on the functional effects they have on joints?
extensor
flexor
adductor
abductor
sphincter
dilator
levator
depressor
rotator
What are the accessory structures of muscles?
1) FASCIAE
2) BURSAE
3) TENDON SHEATHS
What are fasciae?
- muscles are individually sheathed in fasciae
- expansive, thin, meshlike sheets
- consist of collagen and elastic fibres
Which direction are fasciae oriented?
the same direction as the tension and stress forces acting upon the muscle.
What is the function of fasciae?
- origin and attachment sites for muscles,
- provide support for surrounding tissues (by forming ringlike structures),
- help reduce friction,
- play a supportive role for the tissues and organs.
What two layers can fasciae be divided into?
1) Superficial fascia: thin
2) Deeper layer (superficial
profunda): thicker and stronger
What are synovial bursae?
- enclosed in a capsule of connective tissue
- vary in size
- always filled with synovia
- compared to small gel cushions located beneath tendons
What is the function of the synovial bursae?
evenly distribute pressure originating from the tendon
What are the two layers of synovial bursae?
stratum synoviale (inner)
stratum fibrosum (outer)
