Posted at 10.06.2018
By now you will be familiar with the essential structure and business of muscle (specifically, skeletal muscle). In such a chapter we want to expand after your understanding of muscle by looking at how it really works and look more specifically at muscular parts as well as some basic muscle nomenclature. In chapter nine we looked at the three types of real human muscle, specifically cardiac, soft and skeletal muscle. In this section we will increase after our knowledge base of the three types of muscle but will focus mostly on the properties of skeletal muscle. Skeletal muscle is probably the most adaptable of human muscle because of the number, sizes and shapes of skeletal muscle. Additionally it is the largest & most powerful. However, even though skeletal, cardiac, and easy muscle are structurally and mechanically different, they all basically operate the same way once a stimulus has been provided. Therefore, all muscles have similar actions even though their duties may differ. In this next section we will have a look at the basic obligations and activities of muscle. The standard function of muscle can be described as a contraction. However, this contraction will come in many varieties allowing muscle to perform a great variety of actions both precise and powerful.
Human muscle can generate huge amounts of absolute push, although animals can handle sustained feats. However, whenever we talk about comparative strength humans are actually quite weak in contrast to other species. That's why over the years we've developed tools at work to replace our basic durability deficiencies. Here are some interesting little facts on muscle:
Fleas can hop more than 130 times their own height. If a people could do this we would be able to jump practically 800 ft or scale large buildings in one hop as Superman often does indeed!
Our strongest muscle is our masseter muscle inside our jaw that we use for gnawing. It is determined these muscles can generate almost 1000 pounds of drive. Please don't try this as you will likely shatter your tooth!
The smallest muscles in the torso are found in your hearing - the stapedius.
Our largest muscle is our gluteus maximus.
Unless we could unconscious our muscles are always under some anxiety.
Muscles under too much pressure for too much time form fibrous clumps known as knots. Rub is good for breaking these us.
As you can see, our muscle, especially skeletal muscle, is highly versatile. Let's now have a further check out a few of its properties.
Our body is capable of relocating many ways. Various systems can be found in the body to help in this movements and the skeletal muscle system is the most clear and considerable. Other factors that cause movements are small cilia (hairs), flagella on the surface of cells (flagella are tail like set ups such as a sperm tail), gravitational force. The majority of our movements is via muscle but our muscles likewise have other functions (albeit indirectly related to motion). Listed below are other duties of muscle.
1. Production of Body Heat. As our muscles contract they produce heat. A lot more they contract the more warmth they produce and vice versa. That's why when we exercise we get hot but might desire a blanket over us while lying down on the couch watching TV. Our body temps of @ 37 C. is preserved by the thousands of reactions and motions that occur daily (even at snooze) and require muscle contraction. When these activities are not enough to maintain our body temperatures our muscles can stimulate an additional system to produce warmth. Yes, you guessed it, shivering, which can increase temperature production up to 10 times normal levels for a short period of time.
2. Body Motion. This is the most apparent function of muscle. Most of our muscles are mounted on bone fragments to be pulled in different directions to assist in walking, swimming, bicycling, etc. Later in the chapter we can look in more detail at movements specific functions such as agonists and antagonists.
3. Maintaining Position. Bear in mind we said previously that unless we're unconscious there is certainly some extent of muscle contraction always present. Sometimes we might not even realize our muscles are contracting. But consider this: even while you be seated (or stand) here and read this, your throat, back and arm muscles are contracting to maintain your posture. If you walk they do the same.
4. Respiration. The movement of our own diaphragm up and down we can create negative and positive pressures that permit air to go in and out in our lungs.
5. Talk. The serious and correct muscles in our face allow us to discuss, gesture, etc. and eventually communicate.
6. PULSE. The constant contraction and relaxation of your cardiac muscle allows us to constantly circulate our blood vessels and its nutrients.
7. Constriction of Vessels and Organs. The easy muscle in these tissues we can regulate the blood circulation, food, water, feces, etc. by constricting or dilating our vessels.
8. View. Our potential to broaden and filter our pupils we can see and also prevent too much light harm from joining our sight.
Thus our muscles perform a side variety of essential rather than so essential functions. And although were more worried about skeletal muscles for our studies, we should acknowledge these other important functions. The functions of muscle in the above list involve skeletal, cardiac and simple muscle. Let's take a more detailed take a look at specific functions of skeletal muscle.
In kinesiology, almost all of our emphasis and analysis of muscle is concerned with the way skeletal muscle functions. It really is in this particular role of motion that we see muscle undertake many assignments. These roles include action as an agonist, antagonist, stabilizer, neutralizer, and synergist. A muscle can nearly act to execute any of these roles depending upon the nature of the muscle action. We often make reference to these as capabilities of muscle activities.
The term agonist is used to spell it out the muscle when it is performing as the excellent mover or best muscle within an action. The agonist muscle creates a torque in the same route as the joint action (or airplane). In other words, the agonist is the muscle (or muscles) that are behaving concentrically during the action in which their joint is included. Sometimes there exists more than one agonist in a movement so when this happens we normally lengthen our definitions to include the terms key and associate (or supplementary) agonist. The muscles can be known as best movers or protagonists. From a terminology viewpoint there should always be considered a muscle and joint described when discussing agonists. Each one of these terms, agonist, prime mover, and protagonist, are considered undefined unless the joint action is also defined. So, for example, "in elbow flexion the agonist is the biceps brachii" is the correct statement, whereas "the biceps brachii is an agonist" can be an incomplete statement. Do a biceps curl in a good straightforward movements to illustrate the many functions of agonist, assistant agonist, etc. Within this motion which is properly described as elbow flexion, the biceps brachii and the brachialis become the agonists, as the brachioradialis, extensor carpi radialis longus and pronator teres become assistant agonists.
That was actually an extended conversation on agonists but the backdrop information will last well even as we consider the other conditions. An antagonist is the muscle that creates amount of resistance or torque opposite the agonist. They do that by developing power eccentrically as the agonists are contracting concentrically. Normally antagonists and agonists are positioned on the opposing attributes of any joint. Within the above exemplory case of elbow flexion the triceps would be the antagonists. The primary role of antagonists is absolutely to provide a breaking action to decelerate the contraction especially if it involves an extremely powerful and fast motion like tossing a fastball. Conversely the role of agonists is to provide an acceleration motion. While agonists and antagonists will be the two most evident assignments muscles play, they certainly play other important but less clear tasks. These other jobs are often collectively termed synergistic functions with the muscles referred to as synergists. Synergists usually take on two roles known as stabilizers and neutralizers. Synergistic muscles are usually operating in a less obvious but cooperative way to agonists. One role is that of a stabilizer. (Sometimes referred to as fixator or supporter. ) When muscles action there are numerous forces acting upon the muscle that may cause it to act in a fashion that is unwanted. Stabilizer muscles usually exert their result and force with no noticeable action motion in the muscle. Let's take the deltoid muscle for example. The deltoid muscle has two main tasks. The first & most obvious is to move the humerus. It can help lift our biceps and triceps up. The second, however, is a stabilizing role as it can help press the head of the humerus in to the shoulder socket. This traction force action of tugging the humeral go to the socket is a stabilizing role. The stabilizing action of your muscle can usually be determined by its static contraction properties. The action of steadying bone fragments at the joint around that they rotate is probably the most typical action of stabilizing muscles.
Another important role of muscle is the action of a neutralizer. Remember we have over 400 muscles in the body and most of them are contracting in virtually any given activity even though their functions may be nominal. Often these functions are that of a neutralizer that essentially defined is a muscle that serves to avoid an unwarranted action during a movement. One common example often cited to demonstrate the neutralizer theory is that of elbow flexion. During elbow flexion (e. g. a biceps curl) the biceps brachii produce forces that cause flexion of the elbow but also supination (rotation) of the forearm. Since elbow flexion i. e. the bicep curl, is really the only action wished, something has to neutralize the supination action. This is attained by the pronator teres which is that small muscle that operates across the inside of your elbow. Thus we can see that a muscle can have four specific movement responsibilities. Particularly, agonist, antagonist, stabilizer and neutralizer. The variability in muscle motion function means that lots of of our muscles can actually perform all actions, although this is rarely the truth.
You will have noticed that we have recently been referring to different mucles in our discussion of architecture and role. For example, we have referred to the deltoid, pronator teres and biceps brachii. Believe it or not, muscles are named using a fairly easy and logical guide. Essentially, all our muscles are known as according to 1 of four main conditions, namely shape, location, size and function (or sometimes a combination). Some other secondary conditions are also used for decided on muscles plus they include origins and insertion, the number of mind on the muscle, and the orientation of the fasciculi. Soon we can look as of this naming system in more detail. First there are a few other basic terms and information we should be familiar with.
The basic movement of an muscle is contraction or shortening. For the most part this occurs by the muscle tugging two bones together (flexion) since the muscle is usually attached to bone on two ends. However, this isn't always the truth as sometimes a muscle is not mounted on bone at both ends and could in simple fact only be mounted on skin. This is actually the case with several muscles inside our face. No matter, the muscle has two attachment points and they are known as the origin and insertion.
The origin is sometimes known as the fixed end or head and it is the stationary area of the muscle. By this we mean the end of the muscle that is mounted on the least moveable bone in the action. This is the proximal end of the muscle which is usually closer to the axial skeleton or mid-section of your body. For example, in the biceps remedy, the humerus doesn't move but the radius does. The origin of the biceps is at the top of the humerus. The muscle insertion is the other end of the muscle. Additionally it is known as the mobile end or the distal insertion. The attachment occurs on the most movable bone in the action. Utilizing the biceps example again, the insertion occurs on the radial tubreosity (bone) leading to the radius to go to the humerus during a biceps curl. (Fig 10. 1 in Seeley et al. ). Greater strains tend to be employed at the insertion site and often after intense activity the insertion site is more inflamed and agonizing. Now let's get back to muscle naming and classification.
As we mentioned, muscle is normally known as using one (or more) of the next main standards: form, location, size and function. Also, some secondary requirements are often used.
shape, location, size, function, origins and insertion, the amount of heads on the muscle, orientation of the fasciculi.
Depending on the written text you use you will see different terminology for muscle designs. In this content material I'll present the several forms under the headings we used earlier namely, pennate, in a straight line and circular.
Our muscles are established in a variety of shapes and are usually grouped into three classes as a function of the way in which the fasciculi are set up. That is sometimes referred to as (angle of) pennation. The three arrangements are pinnate, straight (or fusiform) and circular. Contained within these three preparations are sub-classifications of arrangements. The orientation of the muscle fasciculi (or fibers) has several implications for the muscle action. The orientation impacts how much movement may appear by the muscle and indeed how much make it can produce. In terms of simple biomechanics we can consider our muscle fibres to be either in parallel design (fusiform) or a feather-like set up (penniform). The fusiform agreement pertains to muscles whose structures comprises largely muscle fibres that run parallel and longitudinal. The penniform agreement pertains to muscles whose fibres are normally brief, feather-like in appearancde and attach to more than one tendon. The primary differences between the arrangements are that the pinnate design facilitates more pressure production as the fusiform arrangement facilitates more movement. If you believe about the big, strong muscles in your back and chest, you will see these have a far more penniform layout. The muscles in your hands are usually more fusiform and allow more freedom but produce less push. Let's take a look at some arrangement details in more detail.
Pennate (or penniform) materials are usually structured in a diagonal orientation or, more specifically, feather-like orientation. Pennate originates from the Latin "Pennatus" signifying feather. Inside the pinnate agreement the fasciculi can run in multiple guidelines and therefore pinnate fibers are further labeled as unipennate, bipennate or multipennate (Use fig 10. 2a in Seeley & Tate). If the muscle is strictly such as a feather, meaning the materials are divided on two edges of the same tendon, the look is known as bipennate. In general, the bipennate agreement is seen as a a single tendon running between the muscle fibres which increase in a diagonal orientation from the tendon out. Both edges of the tendon appear symmetrical and it truly will resemble a feather. An example of a bipennate muscle is the rectis fe____ muscle in the quadriceps. As opposed to the bipennate muscle is the unipennate (or semipennate) muscle arrangement. In this agreement all fasciculi are on the same aspect of the tendon. The tibialis posterior muscle in the leg is an example of a unipennate muscle. The ultimate pinnate arrangement is multipennate. In this particular set up the fasciculi are set up in multiple corations around multiple muscle tendons with the fibres again jogging diagonally between them. The deltoid muscle is a nice exemplory case of a multipennate muscle. Other muscles that also technically are categorized as the in a straight line classification are quadrate and rhomboidal. In these orientations the muscle fibers still run in a parallel orientation but are more square and rectangular in appearance. These muscles appear as four sided and are usually even. Muscles of the appearance usually have it mirrored in their name, for example, pronator quadratus on your wrist or your rhomboid muscle on your rear.
Other muscle orientations that typically are categorized as the pinnate classification include triangular or enthusiast molded muscles although in every reality this condition of muscle should be categorized as multipennate. Fan formed muscles are pinnate in set up and also resemble quite strongly the shape of a "hand enthusiast. " These muscles are relatively toned and the fibres task outwards from a narrow attachment almost resembling a garden bush. So they have a thin attachment at one end and a wide attachment at the other. Our pectoralis major muscle on our chest is a good example of a triangular muscle.
There are multiple conditions used interchangeably to make reference to straight muscle. You will notice the terms direct, fusiform and longitudinal and although they are all popular, there are simple variations. In general, straight muscles have fasciculi arranged parallel to the long axis of the muscle. Firmly speaking this description really refers to a longitudinal muscle arrangement. The santorius and hyoid muscle are examples of longitudinal muscles. A fusiform muscle still contains parallel fibers working longitudinally, however, fasiform muscles tend to be more tapered at either end. These muscles can be long or brief in length as opposed to straight muscles which are usually only long. Examples of the fusiform orientation are considerable and include our biceps brachii and gastroznemuis. A general distinguishing appearance is that fusiform muscles tend to be spindle-like to look at versus straight muscles which are incredibly thin rectangular in appearance. Therefore the term longitudinal is the greater obsolete guide of the three terms.
The final form classification of muscle is the orbicular muscle (see figure 10. 2 Seeley). Sometimes known as circular, the orbital muscles are circular in orientation. The muscle materials are sorted out in a circular form and are a unique feature of sphincter muscles and of course the eye muscles. The primary role of the muscles is to open and close to permit light, liquid, etc. to get into or exit.
The next classification for naming muscle is muscle location. Utilizing a conventional anatomical procedure, we can refer to a particular body region, AKA location. For instance, in our arm we have several "brachial" constructions. We've the brachial artery, the brachial plexis, the brachioradialis and, of course, the biceps brachii. The biceps term instructs us this is a two going muscle in the "brachial" region in that way using its location to determine its name. Gluteus is a term for buttock and pectoralis is a term for chest. This enables us to work with the location to look for the muscle name. In addition, these terms imply a body location and inform us of in which a particular muscle can be found. You will see shortly that incorporating location and function is a common way for naming muscles as it not only defines muscle by location but also by function.
The fourth main category for classifying muscle is muscle function, i. e. what does the muscle do for a motion structure in its key role? As we know, muscles can move around in many ways, e. g. , flexion, abduction, or elevation. Sometimes this descriptive term is put into the muscle to give the muscle a name. In using this approach the activity term is usually used in blend with another naming descriptor. For instance, the erector spinae. Erector is the term to imply erect, or elevate or lift up, while "spinae" is the positioning. Collectively, these terms tell us that the muscle is on the trunk or spine and it erects or lifts. Another example will be the flexor carpi radialis. Flexor is the motion or function, carpi is the area (hands) location and "radialis" provides additional location information. That is an effective method for naming muscles in that it typically provides us with a bit more home elevators the muscle itself.
The other staying categories that are less common are orientation of the fasciculi, origin and insertion and the number of muscle mind.
-- Orientation of fasciculi. The two main orientation terms are rectus and oblique. These terms are used to describe a muscle which has a right muscle fasciculi orientation (rectus) or an angular muscle orientation (oblique). Good examples will be the rectus abdominus and the rectus oblique.
-- Origins and insertion. This nomenclature is utilized to describe a muscle based on its starting (origin) and finishing (insertion) point. For instance, the brachioradialis originates on our arm (brachium) and ends or inserts onto the radius. The sternecleidomastoid is another example.
-- Number of minds. This nomenclature is employed to describe the number of heads on a particular muscle and is usually found in connection with location. For instance, biceps means two minds, while triceps means three mind. The addition of the term brachii to both offers us location.
In all, we have seven means of naming muscles but four categories - size, location, condition and function - are mainly used.
We have already looked at the essential meanings of the conditions source and insertion. But let us take a quick recap. The origin of an muscle is usually considered the starting place and occurs closest to the midline of your body. It is also minimal movable end of the muscle in terms of range of motion. The insertion or closing point is further from the midline which is often referred to as the distal point (proximal can be used for origin). This connection site is usually the most movable location in conditions of range of motion and usually is the region of the muscle that encounters the greater stress during motion. Remember, for the most part muscle starts using one bone and ends on another which is this arrangement which allows for skeletal movements. Generally, the long bones have greater ranges between roots and insertions and this distance is also what allows our sweeping locomotion movements.
Determining the foundation and insertion of the muscle is very something you must learn and memorize and then recall through manual practice. Since every muscle essentially has an source and insertion there are practically thousands in the body. For our purposes in applied kinesiology we can look only at the major locomotion muscles of the top and lower torso and consider their roots and insertions. They are summarized and presented in table form.
Upper body muscle roots and insertions
biceps brachii, triceps, pectoralis, barachioradialis, deltoid, rectus abdominus, latissimus dorsi.
Lower body muscle origins and insertions
quadriceps (vastus medialis oblique, rectus femoris, vastus lateralis, vastus intermedius) sartorius, tibialis anterior, gastrocnemius, soleus, hamstrings (biceps femoris, semitendinosus, semimembranosus).
process, and scapular
Spinous processes of T7-L5; sacrum and iliac crest; poor angle of scapula in some people
Clavicle, sternum, superior six costal cartilages, and abdominal aponeurosis
Medial crest of intertubercular groove
Lateral crest of intertubercular groove
Medial and lateral pectoral
Flexes and expands shoulder;
abducts and medially and laterally rotates arm
Adducts and medially rotates arm; extends shoulder
Flexes shoulder; adducts and medially rotates arm; expands make from flexed position
Long mind -
Short mind - coracoid process
Long mind - infraglenoid tubercle on the lateral border of scapula
Lateral brain - lateral and posterior surface of humerus
Medial head - posterior humerus
ridge of humerus
Radial tuberosity and aponeurosis of biceps brachii
Olecranon procedure for ulna
Styloid procedure for radius
Flexes make and elbow; supinates forearm and hand
Extends elbow; stretches make and adducts arm
Rectis femoris -
anterior inferior iliac spine
Vastus lateralis -
greater trochanter and linea aspera of femur
Vastus intermedius -
body of femur
Vastus medialis -
linea aspera of femur
Anterior superior iliac spine
Long head - ischial
Short head - femur
Patella and onto tibial tuberosity through
Medial aspect of tibial tuberosity
Head of fibula
Medial condyle of tibia
and guarantee ligament
Long mind - tibial
Short head - common fibular
Extends knee; rectus femoris
also flexes hip
Flexes hip and leg; rotates thigh laterally and knee medially
Flexes leg; laterally rotates calf; extends hip
Flexes leg; medially rotates knee; tenses capsule of leg joint;
Flexes leg; medially rotates calf; extends hip
Medial and lateral condyles
Fibula and tibia
Through calcaneal (Achilles) tendon to calcaneus
tendon to calcaneus
Plantar flexes foot; flexes knee
Plantar flexes foot
1. Identify the way the following muscles are grouped and if they are penniform or fusiform. Know also where they are located!
a. Pectoralis major
b. Teres minor
c. Extensor digitorum
d. Serratus anterior
e. Trapezius major
g. Gluteus maximus
h. Depressor labii inferioris
I. Lattisimus dorsi
j. Adductor magnus
Can you identify between and give examples of the following:
a. Smooth Muscle
b. Cardiac Muscle
c. Striated Muscle
Identify and express four common characteristics for any muscle types:
Identify and describe 5 factors that influence muscle contraction for
What do we signify whenever we use the terms voluntary and involuntary?
Muscles are typically classified regarding to four standards. Identify the four standards and offer a muscular example to aid your answer!
What is the essential difference between a fusiform and a penniform muscle ?
Differentiate between your parallel and series flexible component.