Question | Answer |
Fiber arrangement affects | 1. Muscle's ability to exert F
2. ROM |
Greater cross section diameter= | Greater F exertion |
Longer muscle= | Greater ROM |
2 major types of fiber arrangements | 1. Parallel
2. Pennate |
Parallel Muscles | Fibers arranged parallel to length of the muscle
Produce >ROM |
Types of Parallel Muscles | Flat
Fusiform
Strap
Radiate
Sphincter (Circular) |
Flat | Ex- Rectus Abdominus, External Oblique
Thin and broad, originating from sheet like aponeuroses
Forces are spread over a broad muscle |
Fusiform | Ex- Brachialis, Biceps Brachii
Spindle-shaped w/ central belly that taper into tendons on each end
F is focused onto small, bony targets |
Strap | Ex-Sartorius
Uniform in diameter
F is focused onto small bony targets |
Radiate | Ex-Pectoralis Major, Trapezius
Triangular or Fan-Shaped or Convergent
Flat+Fusiform |
Sphincter (Circular) | Ex- Orbicularis Oris
Endless Strap Muscles
Surrounds openings and functions to close them upon contraction |
Pennate Muscles | shorter fibers
arranged obliquely to their tendons
> Cross sectional diameter...> Power |
Types of Pennate Muscles | Unipennate
Bipennate
Multipennate |
Unipennate | Ex- Biceps Femoris, Extensor Digitorum Longus, Tibialis Posterior
Fibers run obliquely from tendon on one side ONLY |
Bipennate | Ex- rectus femoris, flexor hallicus longus
Fibers run obliquely on both sides of a central tendon |
Multipennate | Ex-Deltoid
Several tendons with fibers running diagonally btwn them |
Strongest Contraction produced by | Bipennate and Multipennate |