W4: Major Skeletal Muscle Groups

Question 1

Categories of regional musculature

Answer 1

Head and neck, abdominal wall, pelvic floor, upper and lower limbs

Question 2

Categories by defining movements

Answer 2

Abduction (movement away from midline)
Adduction (movement towards the midline)
Flexion (movement forwards)
Extension (movement backwards)
Circumduction, inversion, eversion, supination, pronation, protrusion, retraction

Question 3

Size relating to name of muscle

Answer 3

Vastus (huge), maximus (large), longus (long) minimus (short), brevis (short)

Question 4

Shape relating to name of muscle

Answer 4

Deltoid (triangular), latissimus (wide), teres (round)

Question 5

Direction of fibre linked to name

Answer 5

Rectus (straight), transverse (across), oblique (diagonally), orbicularis (circular)

Question 6

Location relating to name

Answer 6

Pectoralis (chest), gluteus (buttock), brachii (arm)

Question 7

Muscular agonist and antagonism

Answer 7

Agonists = prime movers. E.g., extensors as antagonists and flexors as agonists.

Question 8

What does muscle tone mean?

Answer 8

Muscles are in a constant state of partial contraction. Only part of skeletal muscle activity that is under involuntary control.

Question 9

What does a loss of muscle tone mean?

Answer 9

E.g., by paralysis (loss of innervation). Means the muscles become flaccid.

Question 10

What is the origin of a muscle?

Answer 10

The attachment site that does not move during contraction

Question 11

What is the insertion of a muscle?

Answer 11

The attachment site that does move when the muscle contracts.

Question 12

What can muscles be inserted into?

Answer 12

Tendons and aponeurosis (flattened tendon)

Question 13

What is fascia?

Answer 13

Sheet of fibrous tissue allowing the attachment of muscle.

Question 14

How do skeletal muscles produce movements?

Answer 14

By contracting - shortening of muscle fibres

Question 15

Categorisation of muscles by function

Answer 15

Flexors, extensors, abductors, adductors, sphincters, dilators, levator (to lift or elevate a structure), masseter (a chewer)

Question 16

Categorisation of muscles: pennate structure

Answer 16

Pennate muscles have long parallel tendons with short muscle fibres arranged between them at an angle (Image at min15). Unipennate, bipennate, multipennate (image at 16:50)

Question 17

What do multipennate muscles allow for?

Answer 17

Multipennate muscles allow packing of more muscle fibres, makes for powerful muscles. The more pennate the muscle, the more powerful it is.

Question 18

What can happen when tendons are prone to compression?

Answer 18

When tendons are prone to compression, sesamoid bones may develop, e.g., patella. A bone not attached to any other bone in the body.

Question 19

How do wrinkles appear in the skin?

Answer 19

The face has no distinct deep fascia. As skin ages, it becomes less elastic. Wrinkles in the skin appear at right angles to the muscle fibres in muscles of facial expression.