Isotonic and Isometric contractions of the muscle

  I have been drawing muscles as contracting by shortening for you.   That’s a bit of an oversimplification.  What is certainly true is that whenever a muscle contracts, it does so by shortening of sarcomeres (or at least by trying to shorten its sarcomeres).

    Have you ever tried to pick something up that was really heavy, only to find out that you couldn’t lift it?  Or, how about, have you ever pulled on something, like a door handle, but didn’t open it?  In these situations, you contracted muscles, but they did not shorten.

    There are two major terms for types of contractions:  isotonic and isometric.  The isotonic contractions are ones when your muscles actually shorten.  The isometric contractions are ones when your muscles don’t shorten.  Your book has the following figure it uses to try to distinguish these two types:

isotonmet.jpg (24629 bytes)

    Consider what these terms “isotonic” and “isometric” mean by picking them apart.  “Iso-” always means “the same.”  So you can have a same-tonic or same-metric contraction.   Now let’s consider the suffixes.

    Muscle always has tone.  What is muscle tone?  Our muscles are not limp, but there are some connected cross-bridges that keep them somewhat taut.

    So, isotonic means that a muscle has the “same tone” throughout its movement.  In other words, the muscle maintains tone and never gets saggy while shortening.  If you think about this, it should make sense.   If I were to bend your arm for you, so that your forearm flexed, the muscle in the diagram above would be shortened by an external force (me) rather than by electrical activation from the nervous system.  If I do the flexing for you, then, as your muscle was externally shortened, it might go saggy.  However, if you voluntary contract this muscle, causing the shortening yourself (through nervous system activation), the muscle will never get saggy.  It will maintain its tone throughout your movement.   Got it?  Same tone?

    Whenever you see the term “metric,” you should think of meters in the metric system.  Meters are length measurements.   Therefore, isometric means “same length.”  If you contract your muscle but don’t let it shorten, the muscle maintains its same length.

    The only confusing point here is how does the contraction occur if the muscle doesn’t change length?  Well, it doesn’t change length from attachment site to attachment site, but it does pull at its tendons, stretching the tendons a little bit while the muscle tissue pulls in a bit.  This is what happens when you flex your arm and show off your muscles.  If you hold your arm flexed and then increase your contraction force (but don’t bend your arm any more), you will see a bulge in your upper arm that is due to the isometric contraction you just caused.  The reason that it is still considered isometric is because this contraction force did not produce any movement (additional flexion or extension), but your limb remained fixed in position.



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Joints Range of Motion Lecture 3


Range of motion of the joints:

T.M.J: Temporal Mandibular Joint:

  1. Depression

  2. Elevation

  3. Protraction

  4. Retraction

  5. Left Deviation

  6. Right Deviation

Cervical Spine: (head/neck)

6 motions: only the neck and head.

  1. Flexion

  2. Extension

  3. Left Side Bend

  4. Right Side Bend

  5. Left Rotation

  6. Right Rotation

*Remember Client Care: must protect the clients when doing lumbar assessment.

RMT priority:

1: Safety-Reduce the risk

2: Effectiveness

3: Always protect your client.

For example: “Can you stand while you perform these motions?”

Show client care by assisting them.

Thoracic Spine:

Subtle 6 motions.

Lumbar R.O.M:

6 motions

Knee R.O.M:

Flexion= Open


  • when knees are open, can rotate medially, laterally.

Ankle: R.O.M:

  1. Plantar Flexion

  2. Dorsal flexion

  3. Inversion (inwards)

  4. Eversion (outwards)

Shoulders Joints: Must perform full range of motion: Do you feel pain/numbness?

Hands up—lateral rotation

Hands cuffs—medial rotation

  1. Flexion

  2. Extension

  3. Adduction

  4. Abduction

  5. Medial rotation

  6. Lateral rotation

  7. Horizontal adduction

  8. Horizontal abduction.

Elbow: R.O.M

  1. Flexion

  2. Extension

  3. Pronation

  4. Supination

Wrist: ROM:

  1. Flexion

  2. Extension

  3. Medial Deviation-Adduction

  4. Lateral Deviation-Abduction

Thumb: ROM:

  1. Flexion

  2. Extension

  3. Adduction

  4. Abduction

  5. Opposition

Massage benefits; offers relaxation, improve muscle health, improve range of motion, reduce fascia tension, improve circulation

Range the motion: is part of the assessment.

Skin pathology: some are contagious, should be aware.

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Anatomy: Lecture 2: Anatomical Orientations/Directions/ Locations


Body Planes (Anatomical Directons)



1: Saggital Plane: Separates the body into the Right Side and Left Side. *Numerous planes available.



Mid Saggital: Equal/Balanced of the left and right side from the middle



2: Coronary Plane: Or Frontal plane: numerous planes available.


*no equal symmetry for this plane. Separates the body into the front (anterior) and back (posterior).



3: Transverse Plane: Contains superior/inferior (upper half, lower half).





Direction: Anterior to _________, Posterior to _________



Example: The nose is anterior to my ears. The ears are posterior to the nose.





Superior ~ to Upper…


Inferior~ to Lower…



Superficial: Close to the skin/surface



Deep: Close to the deeper layers.



Distal: Far away from the main mass/body trunk.



Proximal: Closer to the main mass or body trunk of the trunk.



*Any structure close to the middle of the body, we call it MEDIAL: midline of the body.



Cephalic: Towards the head, similar to Superior.



Caudal: Towards the tail/back, similar to Inferior.



Ventral: Anterior



Dorsal: Posterior.



  • Example: Please perform the manual lymphatic cephalically.



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Introduction to Anatomy: Summary


Lecture 1:

Anatomy/ Physiology/Pathology

Levels of Life:

Organic/ Inorganic

—–> Composition of an Atom: Contains a Nucleus (neutral), Protons (neutral) and Electrons (negative)

—-> Molecules

  • Oxygen: The most mass contained within the body (65%)

Gross Anatomy: Studying anatomy with your eyes instead of a microscope

Organic Molecules: Carbon, Hydrogen, Oxygen, Nitrogen.

Inorganic: Does not contain the 4 molecules ( Carbon, hydrogen, oxygen, nitrogen)

Atomic: the basic unit of matter

-Contain nucleus (N)

-Proton (+)

-Electron (-)

*contains 65% Oxygen


-Inorganic molecules. Examples: Rocks

Organic Molecule (Carbon, Hydrogen, Oxygen, Nitrogen)

Organic Molecules (C. H. O.N)

The beginning of life known as BIOMEGA MOLECULE: for example carbs, lipid, proteins.

Living creatures contains CELLS:

Cell: basic unit of the living creature. Cells forms tissues


1: Epithelial Tissue

2: Muscular Tissue (skeletal muscles, cardiac muscle, smooth muscles).

*Skeletal muscles are voluntary

*Cardiac muscle and smooth muscles are not voluntary (Involuntary)–continuous contractions and retractions.

Human beings are “Organisms” consisting of many systems in cooperation with each other.

Tissues forms organs such as eyes, ears, nose, brain, stomach, heart, liver

Organs turns into systems tissues such as epithelial, muscular, connective tissue, and nervous tissue.

Connective tissue: blood, lympathic vessel, bone, ligament, tendons, (adipose: fat)

Cerebral Spinal Fluid (C.S.F)

Nervous Tissue: Central Nervous System

Organs forms a system:

For Example: Digestive System:

Food–> Esophagus–>Stomach–>small Intestine–>large intestine–>rectum.

There are many systems such as the respiratory sys, digestive sys, reproductive sys, cardiovascular sys.

Cell Structure:

1: Cell membrane contains bi-layer of phospholipid, and this is because water can enter freely into the cell.

2: Cytoplasm: contains cytosol (a fluid)

3: Nucleus—DNA for duplication.

4: Organelle: subcellular structure contains mitochondria, ribosome, lysosome.

A: Mitochondria: a site to produce energy

B: Ribosome: site for the synthesis of protein.

C: Lysosome: destroys foreign bodies (I.E: viruses).

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Latin Names and Translation for easy understanding of muscles in the body

Latin names of muscles:

Opponens: Opposite

Minimi= Small/ Least

Digiti==pointing things. i.e. Fingers/Toes

Palmaris= Palm/flat of the hand

Pronator= turns downwards

Supinator= Turns upwards, i.e cupping

Quadratus= square muscles

Teres= Round

Biceps= Two headed muscles

Triceps= Three headed muscles

Quadriceps= Four headed muscles.

Brevis= Short

Longus= Long

Abductor= Abducts, pull away or taken away, i.e. Kidnap the muscle away

Adductor= adducts, to bring back together, to come closer together,

Pollicis= Thumb

Hallucis= Big toe

Brachii= Arm, related to the arm

Brachialis= Muscle of the arm

Deltoid= triangle=like shaped muscle

Buccinator= Trumpeter muscle..i.e blowing the trumpet

Anguli= Corner of…..i.e Corner of the mouth

Oris= Mouth

Depressor= Depresses, press down

Levator= elevate, to lift up

Labii= Lip

Superiorius= Upper

Inferiorius= Lower

Omo= Shoulder

Hyoid= Hyoid bone

Sternocleidomastoid= Muscle that connects the sternum, clavicle, mastoid process

Zygomaticus= yoke-shaped

Major= Greater

Minor= Lesser

Femoris= Thigh

Gastrocnemius= Belly muscle of calf

Gracilis= slender muscle. I.e Graceful and Slender muscle.

Peroneus= Pointed bone. Same as Fibularis Longus

Fibularis= pointed bone. Same as peroneus bone. Hence, Fibularis Longus is easier to understand since the muscle is attached to the fibula.

Cervicis= Neck

Capitis= Head

Trapezius= Four sided muscle

Carpi= Wrist

Piriformis= Pear shaped

Abdominis= belly muscle

Masseter = Chewer muscle

Psoas= Loin

Rectus= Straight

Soleus= sandal muscle, sole of the foot

Vastus= Enormous

Medialis= middle

Lateralis= Side

Intermedius= In-between the middle

Latissimus= Broadest

Dorsi= Back

Splenius= bandage

Rhomboid= Parallelogram shaped muscle.

Pectoralis= breast muscle


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Massage Therapy Notes: Muscles of the face

Muscles of the face are innervated by the Cranial Nerve #7 or in Roman numeral IV.

* Cranial Nerves, also known as Facial nerves contains 12 pairs.

1: Corrugator Supercilli

Latin: Wrinkler above eyelashes

Refers to the vertical wrinkle forehead innervated by the facial nerve.

2: Obicularis Oris:

Latin: Little circles(Obicularis) around  (Oris)mouth.

Muscle of the mouth in a circular  form.

Function: open, close, kiss, eat, whistle, speak. so forth.

3: Zygomaticus Minor and Major:

Function: The smiling muscle.

Latin: Minor= lesser, Major= greater: Hence The major or lesser muscle of the Zygomatic bone.

Some muscles works in synergistic manners such as Zygomaticus minor and major with another muscle.

*The synergists for this the zygomaticus minor/ major muscle is the RISORIUS MUSCLE.

4: Risorious:

Function: Smiling muscle.

The antagonist muscle for Risorius is the Depressor Anguli Oris.

5: Lavator Labii Superiorius:

Function: Upper lip elevation

N: Facial nerve 7.

6: Depressor Labii Inferious

Function: Lower lip depression

Nerve: Facial Nerve 7

7: Depressor Anguli Oris:

Function: Facial expressions of sadness or depression. AKA: Tragedy Mark.

*Antagonist Muscles of both Zygomaticus minor and major, and Risorious muscle.

8: Orbicularis Oculi:

Latin: Little circles around the eyes.

Function: Muscles that surround the eyes to help you close and open your eyes. Creates the wrinkles around your eyes.

9: Mentalis:

Latin: meaning chin.

Function: wrinkle of the Chin.

10: Buccinator:

Latin: Trumpeter muscle (muscle used in blowing).

Function: sucking, swallowing, biting, holding foo dint he mouth.

3 characteristics:

1: Side wall of oral cavity

2: Sucking muscle, especially important during infancy

3: Trampoline-like muscle.

11: Platysma:

Latin: “Wide”, thin, flat muscle

Function: Creates tension of the neck, depression of the lower mandible.

N: Facial Nerve #7.

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Massage Therapy Notes: Muscle of the Skulls

Muscle of the Skull

A.K.A: Epicranius: contains 2 bellies.

1: Frontal Belly called Frontalis of the Occipitofrontalis.

Function: Horizontal wrinkle of the forehead.

Nerve: Facial Nerve IV 7

2: Occipital Belly: Called Occipitalis  of the Occipitofrontalis.

Function: provides cushion, not much function though.

Nerve: Facial Nerve IV 7.

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