Skeletal muscles produce movement by exerting force on tendons, which in turn pull on ones.
When muscle contract, two articulating bone not move equally in response to contraction.
One of bone attach to it remains stationary while other bone moves along with contraction.
Naming skeletal muscles
Muscles are named according to their;
Location
Shape
Size
Attachment site/ origin and insertion
Heads or origins
Orientation/ direction of muscle fiber
Function
1. Shape
Muscle are named according to their shape.
a. Trapezius
Trapezoid (diamond-shaped)
b. Deltoid
Triangular or delta shaped
c. Gracilis
Slender (slim) in shape.
d. Serratus
Saw toothed shape
e. Quadratus
Rectangular in shape
f. Teres
Round in shape
Rhomboid
Diamond shaped
2. Size
Muscles name according to their size.
a. Maximus
Largest muscle; gluteus maximus is largest muscle of buttocks.
b. Minimus
Small muscle; gluteus maximus is smallest muscle of buttocks.
c. Longus
Longest muscle; adductor Longus
d. Brevis
Short muscle; Abductor pollicis brevis
e. Major
Longer muscle; pectoralis major
f. Minor
Smaller muscle; pectoralis minor
3. Location
Muscle named according to structure near which muscle is found.
1. Frontal
Muscle near frontal bone, frontalis
2. Tibial
Muscle near end of tibia, tibialis anterior.
3. Supraspinatus
Above the spine of scapula.
4. Attachment sites/ origin and insertion
Muscles are named according to site where muscle originates and inserts.
1. Sternocleidomastoid
This muscle originates on sternum and clavical and inserts on mastoid process of temporal bone.
5. Heads or origin
Muscles are named according to number of origin or heads they have.
1. Biceps
Muscles having 2 origins/heads
2. Triceps
Muscle having 3 origins/heads
3. Quadriceps
Muscles having 4 origins/heads
6. Orientation/Direction of muscle fibers
1. Transversus
Muscle fibre run prependicular to mid line, transversus.
2. Oblique
Muscle fibers run diagonally to mid line, abdominal external oblique muscle.
3. Rectus
Muscle fibre run parallel to midline; rectus abdominis.
7. Action or Function
Muscle name refer to principal action of muscle.
1. Flexor
Flexion; bending motion in which angle between two bone is decrease.
Decreases angle at joint. Flexor carpi redialis
2. Extensor
Extension; angle between 2 bone increases.
Increases angle at joint. Extensor digitorum
3. Abductor
Abduction; moves bone away from midline of body. Abductor pollicis Longus.
4. Adductor
Adduction; moves bone closer to midline of body. Adductor Longus
5. Levator
Produce upward movement. Levator scapulae
6. Depressor
Depression; produces downward movement, depressor labii inferioris.
7. Supinator
Supination; turn palm upward or anteriorly or Superiorly.
8. Pronator
Pronation; turn palm downward or posteriorly pronator teres.
9. Sphincter
Decrease the size of opening, external urethral sphincter
10. Tensor
Makes body part more rigid, located thigh and knee.
11. Rotator
Moves a bone around it longitudinal axis, rotator.
12. Masseter
Chewing muscle.
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