chapter 11 skeletal muscle

Skeletal muscles

Attach to bones to produce movement by contracting and pulling on tendons.

Origin

The end of the muscle attached to the bone that stays still (fixed in place).

Insertion

The end of the muscle attached to the bone that moves.

First Class Lever

A lever where the fulcrum is in between the load and the effort.

Second Class Lever

A lever where the load is in between the fulcrum and the effort.

Third Class Lever

A lever where the effort is between the fulcrum and the load.

Parallel Muscles

Muscles where fibers run along the axis, offering a lot of movement but lower strength.

Fusiform Muscles

A type of parallel muscle that has a tapered shape.

Convergent Muscles

Muscles that start wide and taper into a single tendon, allowing for a wide range of movement.

Pennate Muscles

Muscles with fibers attached at an angle to a central tendon, allowing for more strength.

Agonist/Prime Mover

The main muscle responsible for a movement.

Antagonist Muscle

Muscles that oppose the action of the prime mover.

Synergist

Muscles that assist the prime mover by adding force to the movement.

Fixator

Muscles that stabilize the origin of the prime mover to allow for more efficient movement.

Orbicularis Oris

Circular muscle of the mouth known as the 'kissing muscle'.

Masseter

Muscle responsible for closing the jaw, originating from the zygomatic arch.

Diaphragm

Main muscle for breathing; contracts to increase thoracic cavity size.

Gastrocnemius

Muscle that flexes the knee and plantar flexes the foot, originating from the femur.

Erector Spinae

Group of muscles that extends and stabilizes the vertebral column.

Gluteus Maximus

Muscle that extends and laterally rotates the hip.

Carpal Tunnel Syndrome

A disorder caused by inflammation of the median nerve in the wrist, leading to pain and numbness.

Golfer’s Elbow

A condition from repetitive strain on the forearm flexor muscles, resulting in pain around the elbow.