CONCORDIA UNIVERSITY DEPARTMENT OF EXERCISE SCIENCE
EXCI 206 - THE SCIENCE OF SPORT
LECTURE NOTES
INSTRUCTOR:
Chantal Comeau, B.Sc., CAT(C), KIN
WINTER 2014 1 EXCI 206
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Introduction to the Science of Sport
THE SCIENCE OF HUMAN MOVEMENT • Kinesiology • Anatomy • Physiology • Biomechanics
Human Movement Specialists • Physical Educators • Athletic therapists ( CAT(C) ) • Physiotherapists (PT) • Occupational therapists (OT) • Exercise scientists scientists / kinesiologists (KIN) • Ergonomic engineers • Athletes
Classification of Human Movement • Basic movements – Walk, run, jump, throw, strike, swim, etc. • Adapted movements – Prosthetics, orthopedics, sports injuries • Goal-oriented movements – Various environments: air, water, sports, work
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• Movement factors – Person’s perception, motivation, goal, condition – Task or Objective – Environment
Sport Science and Movement
Improved Performance
Improved Technique
Equipment changes
Training methodologies
Injury prevention and treatment
Modify strategies
Change in sport surfaces
RECOMMENDED READING
http://www.bases.org.uk
Winter, E. M., Jones, A. M., Davison, R. C. R., Bromley, P. D., & Mercer, T. H. (Eds) (2007) Sport & Exercise Physiology Testing Guidelines. The British Association of Sport & Exercise Sciences Guide. Volume I: Sport Testing. London: Routledge
Review exercises -
Define sport science
-
Explain how sport science can help athletes and coaches
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Anatomical Position
SKELETAL SYSTEM
Directional terms
JOINTS
Anatomical Planes
MUSCLES
Overview The The human body is composed of 11 major jor parts that are loc located with ithin the axial and appendicular portions portions of the body. body. Someof these these major ajor body parts have have smaller all er body parts withi within n them. Sep Separati arating ng two adj adjacent body parts from from each other is i s a joint. True T rue movem movement ent of a body part involves movement of that body part relative to another body part at the joint that is is located located betwee between them.
Major Divisions of the Human Body ○ The hum human body body can be be divi divide ded into into 2 major ajor sections: sections: ○
The axial body
○
The appendicular body
Axial Body ○ The axial body is the central core axis of the body
and contains the following body parts: ○
Hea Head
○
Neck
○
Trunk
Appendicular Body ○ The T he appendicul ndicular ar body is is mad made up of appenda pendages that are “adde “added onto” the axi axial al body.
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○ The The appendicul ndicular ar body body can bedivi divide ded d into into the right right and and left left upper upper extremities ties and and the
right and left lower extremities. ○
xtremity contains the following body parts: An upper extre ○ Shoul Shoulder girdle girdle (scapu (scapulla and cla clavicl vicle e) ○ Arm ○ Forearm ○ Hand
○
extremity contains the following body parts: A lower extre ○ Pelvis Pelvis (pelvic vic girdle) ○ Thigh ○ Le L eg ○ Foot
○The pelvis is often considered to be part of the axial body. In actuality, it is a
transiti transitiona onall body part of both the axial axial body and and the appendicul ndicular ar body; the the sacrum sacrum and and coccyx are axial xial body bones and the pelvic vic bones are appe appendi ndicul cular ar body bones. For symmetry, we will consider the pelvis to be part of the lower extremity (therefore the appendicular body), because the shoulder girdle is part of the upper extremity. Note: The word girdle is used because the pelvic and shoulder girdles resemble a girdle in that they encircle the body as a girdle does (actually, the shoulder girdle does not compl complete etely encircl encircle e the body because cause the two scapula scapulae do not meet in in back) back)..
Major Body Parts artt is ○ A body par is a part part of the body body that can can move move inde independentl ndently y of another another body part that
is next to it. ○ Genera enerallly it i t is i s the prese presence nce of a bone bone (someti (sometim mes more than onebone) withi within n a body body part
that defines nes the body body part. ○ For example, ple, the humerus defines the arm; the radi radius us and and ulna ulna define the the forea forearm. ○ The human body has 11 major ajor body parts
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Regions of the Body Within thin the human body, body, areas areas or reg regions exist exist that are are given given nam names. es. Sometim times these regions regions are are locate located withi within n a body body part; part; sometim etimes they they are are locate located across two or more body parts. Following are illustrations that show the various regions of the body
Anatomic Position A lthough the human body can assume an inf infiinite nite num number ber of positions, one position is used as the reference position for mapping the body. This position is used to name the location of body parts, tion. structures, and points on the body and is called anatomic position. I n ana anatomic posi position tion the person is is :
standing erect facing forward with wi th the arms at at the sides sides the palms facing forward the fi fingers and thumbs extended 7
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Directional Terms
Superior = nearer to the head
Deep = farther from the surface of the body
Inferior= nearer to the feet
Medial = nearer to the median line
Anterior = nearer to the front
Lateral = farther from the median line
Posterior = nearer to the back
Distal = farther from the trunk
Superficial = nearer to the surface of the body
Proximal = nearer to the trunk
WORD ORIGINS ○ Ante—From Latin ante, meaning ning before, before, in f ront of ○ Appe Append—From nd—From L ati atin appendo, meaning aning to hang something something ont o something something ○ Ax—From Latin axis, meaning ning a strai strai ght ght l ine ○ Fore—From Old English fore, meaning ning befor befor e, i n fr ont of ○ Int I nte er—From r—F romL atin inter, meaning aning between ○ Lat L at—From L atin latus, meaning aning side
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○ Post—From Latin post, meaning aning behind, behind, i n the rear, after ○ Supra—F Supra—From rom L atin supra, meaning ning on the upper si de, above ○ Ana A na—From L atin ana, meaning aning up ○ Dors—From Dors—F romL atin dorsum, meaning aning the back ○ Infer—From Latin inferus, meaning aning below, lower ○ Medial—From Latin medialis, meaning aning middle ○ Obli Oblique—From L atin obliquus, meaning ning slanting ○ Rota Rota—From L atin rota, meaning aning wheel ○ Super—Fr r—From omL atin superus, meaning aning higher, sit uated above ○ Tome—From Latin tomus, meaning aning a cutting ○ Tran T rans—From s—From Latin trans, meaning aning across acr oss,, to t he other other side of ○ Ve V entr— ntr—From From L atin venter, meaning aning bell y, stomach stomach
Anatomical planes of the body • Sagittal plane (vertical or “left and right”) • Frontal /coronal plane (vertical or "front and back”) • Transverse plane (horizontal or “upper and lower”)
Sagittal Plane Movements • Flexion • Extension • Hyperextension
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At the ankle : • Dorsiflexion • Plantar flexion
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Frontal/Coronal Plane Movements – Abduction (Lateral flexion) – Adduction – Elevation – Depression – Eversion – Inversion – Radial flexion (deviation) – Ulnar flexion (deviation)
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Transverse Plane Movements – Left or Right Rotation – Supination – Pronation – Horizontal abduction – Horizontal adduction – Inward (medial, internal) rotation – Outward (lateral, external) rotation)
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Review Questions 1 What are the two major divisions of the human body? 2 What are the 11 major ajor body parts of the human body? body? 3 What defines a body part? 4 What hat is is the di difference erence be between tween the thigh thigh and the leg? 5 What hat is i s the dif difference erence between tween the arm and and the forea forearm? 6 What is the difference between the trunk and the pelvis? 7 Name five regions of the human body. 8 What is the position of the body when it is in anatomic position? 9 What is the importance of anatomic position? 10 I f poi point A is located farther toward the front of the body than point B is, is, then how do we describe the location of point A? Point B ? 11 I f point A is located closer to the midline of the body than point B is, is, then how do we describe the location of point A? Point B ? 12 I f poi point A is located on the axial body closer to the top of the body than point B is, is, then how do we describe the location of point A? Point Point B ? 13 I f poi point A is located on the appendicular body closer to the axial body than point B is, is, then how do we describe the location of point A? Point B ? 14 I f poi point A is located both farther toward the front and farther toward the midline of the body than point B is, is, then how do we describe the location of point A? Point B ? 15 I f poi point A is located closer to the surface of the body than point B is, is, then how do we describe the location of point A? Point B ? 16 What is is a pl plane, ane, and and what is is the im importance of understanding rstanding the concept of plane planes? 17 What are the 3 types of plane planes?
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SKELETAL KEL ETAL SYSTEM YSTEM WORD ORIGINS
nner —F rom L atin atin intra, meaning eaning within, i nner ○ I ntra—From
ning not, without ○ A (an)—FromL atin a, meaning
tis—F romGreek itis, meaning eaning inflammation ○ I tis—From
eaning fat ○ A dip—FromL atin adeps, meaning
eaning movement, ○ K ines—From Greek kinesis, meaning motion
○ A rthr—From Greek arthron, meaning eaning a joint
M edulla—From ull a—From L atin medulla, meaning eaning inner portion, ○ Med rticular—From L atin articulus, meaning eaning a joint ○ A rticular—From
marrow
Bl astic—From tic—From Greek blastos, meaning eaning to bud, to build, ○ Blas
Myo— From Greek mys, meaning ning muscle ○ Myo—From
to grow
Num—From rom L atin atin numerus, meaning ning number ○ Num—F C hondr—From rom Greek chondros, meaning eaning cartilage ○ Chondr—F ○ Oid—From Oid—From Greek eidos, meaning eaning resembling, appearance
Cl astic—From tic—From Greek klastos, meaning eaning to break up into ○ Clas pieces
aning study of, discour se, se, ○ Ology—From Greek logos, meaning word
outer por tion of Cortical—From From L atin cortex, meaning eaning outer ○ Cortical— an organ, bark of a tr ee
ossi—From From L atin atin os, meaning eaning bone ○ Os, ossi— Cyte—From Greek kyton, meaning eaning a hollow, cell ○ Cyte—From teo—From Greek osteon, meaning eaning bone ○ Ost, osteo—From inner ○ Endo—F E ndo—From rom Greek endon, meaning eaning withi n, inner
Peri— From Greek peri, meaning eaning around ○ Peri—From Epi—From rom Greek epi, meaning eaning on, upon ○ Epi—F ○ Physi, physio—F physio—From rom Greek physis, meaning eaning body,
eaning outside ○ Extra—From L atin extra, meaning
nature
eaning bandage, band ○ Fascia—From L atin fascia, meaning
Piezo—F romGreek piesis, meaning eaning pressure ○ Piezo—From
Fi br, fibro fi bro—From —From L atin fibra, meaning eaning fiber ○ Fibr,
Poiesis—From Greek Greek poiesis, meaning eaning production, ○ Poiesis—From making
Graph—From Greek grapho, meaning eaning to write ○ Graph—From
Proto—From rom Greek protos, meaning ning first ○ Proto—F
to—From om Greek haima, meaning blood ○ Hem, hemato—Fr
eaning a str str etching ○ Tens—From L atin tensio, meaning
○ Hyaline Hyali ne—F —From rom Greek hyalos, meaning eaning glass
Many any tissue tissues contribute contribute to the structure structure and and functi function on of the skeleta skeletal system; chi chief ef among them is bone tissue tissue. The num number of bones in in the human skel skeleton eton is is usually said said to be 206. 206.
Classification of Bones by Shape ○ Structural Structurallly, bones can be divi divide ded into into four four maj major or categories gories based sed on their shape
The These 4 major jor clas lassifica ification ions by shape are: 15 EXCI 206
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○
L ong bones
○
Flat bone bones
○
Short Short bones
○
I rre rregular bone bones
○ Longbones are long (i.e., they have a longitudinal axis to them). This longitudinal axis is
the sha shafft of the bone bone.. At each end of the sha shafft of a long bone is an an expanded portion portion that that forms a joint (articulates) with another bone. Examples: humerus, femur, radius, ulna, tibia, fibula, metacarpals, metatarsals, and phalanges. Even though some of the phalanges are quite short in length, they still have a longitudinal axis (i.e., a length to them) with expanded ends; therefore they qualify as long bones. Shortt bones are short (i ○ Shor (i.e., the they y are approxim pproximately as wide wide as they are are long, long, and they are
often often describe scri bed as being cube sha shape ped). d). Examples: the carpals of the wrist Tarsal arsal bones bones of theankle nkle region region are also also conside considered to be short bones. bones. A n exception is the calcaneus, which is considered to be an irregular bone, not a short bone.
○
○ Flat bones are flat; that is, they are broad and thin, with either a flat or perhaps a curved
surface. Examples: the ribs, sternum, cranial bones of the skull, and scapula
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○ Irregular bones are irregular in shape (they do not neatly fall into any of the 3
preceeding categories). They are neither clearly long, nor short, nor flat. Th The patella tella (kn (kneecap) is an example of a sesam oid considered to be a type of irregular bone.
bon e . Sesamoid
bones are
Examples of irregular bones are the vertebrae of the spine, the facial bones of the skull, and sesamoid oid bones. amoid bones are so named ○ Sesamoid named because they are are shaped li like a sesame seed—i ed—in other
words, words, they are round. round. Because ses sesam amoid oid bones bones are round in in shape shape, they they are also also known known as round bones. Som Some sources conside considerr sesa sesam moid oid bones bones to be asepa separate fi fifth category category of bones. ○ The The number of sesa sesam moid oid bones in in the human body vari varies es from one indivi ndividua duall to
another. another. The T he only only sesa sesam moid oid bones bones that are consiste consistentl ntly y found found in al all peopl people e are the two patellae (kneecaps).
Parts of a Long Bone No one typical bone exists exists in in the hum human skeleton; skeleton; great dif differences rences in in size size and and shape exist exist among bone bones. s. Even E ven though di differences erences exist exist am among the various various bones bones,, it i t is is val valuabl uable e to examine the the parts parts of a long long bone bone to gain gain a be better understanding rstanding of the typical typical structure structure of bones in general.
Parts of a Long Bone Diaphysis ○ The diaphysis is the shaft of a long bone; its shape is that of a hollow cylindric tube. ○ The purpose of the diaphysis is to be a rigid tube that can withstand strong forces
without bending or breaking; it must accomplish this without being excessively heavy. ○ The diaphysis is composed of compact bone tissue with a thin layer of spongy bone
tissue lining its inside surface. dullary y cavity, which contains ○ Loca L ocate ted d withi within n the dia diaphysi physis at at its its center nter is i s themedullar
bone marrow.
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Epiphysis ○ An epiphysis (pl (plural ural:: epiphyse piphyses) s) is the expanded end end of a long long bone bone found found at each
end end of the diap diaphysis. hysis. He Hence, each long long bone bone has has two epi epiphyse physes. s. ○ The purpose of an epiphysis is to articulate (form a joint) with another bone. ○ By expanding, the epiphysis widens out, allowing for a larger joint surface, thus
increasing the stability of the joint. ○ The epiphysis is composed of spongy bone with a thin layer of compact bone tissue
around the periphery. ○ The spaces of spongy bone within the epiphysis contain red marrow.
tilage. ○ The articular surface of the epiphysis is covered with articular cartilag
Articular Cartilage articular surface urfaces ○ Articular cartilage covers the articular
(i.e., joint surfaces) of a bone. ○ Arti A rticul cula ar cartil cartilage is a softe softer tissu ti ssue e tha than bone bone, and
its purpose is to provide cushioning and shock absorption for the joint. ○ Arti A rticular cular carti cartillage is compose posed of hyaline
cartilage. ○ It I t is is worth noti noting ng tha that articul rti cula ar cartil cartilage has a very very
poor blood supply; therefore it does not heal well after after it i t has been damaged
Periosteum ○ Periosteum surrounds the entire bone, except for
the articular surfaces, which are covered with articular cartilage. ○ Peri Perioste osteum um is a thin thin dense dense fibrous membrane. ○ Peri Periosteum osteum has many purposes: 18 EXCI 206
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○ To provide providea site site of attachm attachment for tendons tendons of muscl uscle es and ligaments. Fi Fibers of
tendons and ligaments literally interlace into the periosteal fibers of bone, thereby firmly anchoring the tendons and ligaments to the bone. ○ To house house cel cells tha that are important portant in form forming and repa repairing ri ng bone bone tissu tissue e. ○ To house house the blood blood vessel vessels s that provide provi de vascular vascular suppl supply y to the bone.
The perioste riosteum of bone bone is highly highly inne innervated rvated with with nerve fibers and very very pa pain sensitive when bruised
○
Medullary Cavity dullary cavity is a tubelike cavity located within the diaphysis of a long bone. ○ The medullary ○ The medullary cavity houses a soft tissue known as bonemarrow (red (red marrow
and/or yellow bone marrow).
Endosteum ○ The endosteum is a thin membrane that lines the inner surface of the bone within the
medul dullary cavi cavity. ty. ○ The endosteum (like the periosteum) contains cells that are important in forming and
repairing bone.
Other Components of a Bone ○ Al All bone bones are are hi highly metabol taboliic organs tha that requi require re a rich rich bl blood supp supplly. The T herefore refore
they are well supplied with arteries and veins. ○ Bones are also well innervated with sensory and autonomic motor neurons (i.e., nerve
cells). The periosteum of bones is particularly well innervated with sensory neurons.
Functions of Bones Bones serve ma many functi functions ons in in our body; body; the five major functi f unctions ons of of bone bones. Of Of these 5 major functions, the first two, structural support of the body and providing levers for body movements, are the two most im important functions unctions for bodyworke bodyworkers, traine trainers, rs, and athl athlete etes, etc.. ○ Structural support support of the body body ○ Provi rovide levers for body movements ents 19 EXCI 206
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○ ○ ○
Prote Protecti ction on of unde underlyi rlying ng structures structures Bloo Bl ood d cell formation tion Storage reservoir rvoi r for cal calcium cium
SKELETAL SYSTEM DIAGRAM BONES IDENTIFICATION
Try to identify the structures in the following the pages. Help yourself with this list. You will have repeats.
Anterior view Posterior view Clavicle Sternum Humerus Radius Ulna Cranium Mandible Scapula Rib Patella Vertebra Tibia Pelvis Fibula Sacrum Carpals Tarsals Metacarpals Phalanges Femur Metatarsals Coccyx
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Sternum Manubrium true ribs xyphoid process false ribs costal cartilage
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THE BONES The skull (22 bones) - 8 cranial - 14 facial
Lateral view – vertebral column
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Anatomy of a Joint ○ Structurally, a joint is is defined ned as a place place of juncture betwe between two or more bones. At A t this this
jun juncture, the bones are join joine ed to one another by soft tiss issue. ○ In other words, structurally, a joint is is def defined as a place where two or more bones are
join joine ed to one another by soft tiss issue. ○ A typical joint involves 2 bones; however, more than two bones may be involved in a
join jointt. Fo Forr example, le, the elbo lbow join jointt inc incorporates three bones: the humerus, radius ius, and ulna ulna. A ny joi joint nt that invol involves ves threeor more more bone bones s of the skel skeleton is is cal called a compound joi joint. In I n contrast, the term simple joint is is sometim etimes use used d to descri describe be a joint oint that that has only two bones. ○ The The typeof soft soft tissue tissue that connects the two bones bones of a joi joint nt to each other other determi determine nes s
the structural classification of the joint ○ ○ ○ ○
The foll ollowing owing are thethree three major structu structura rall cla classi ssificati cations ons of a joint oint:: Fibrous Cartilaginous Synovial
○ A joint oint is is al also known known as as an an
articulation.
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Overview of Joint Function allowmovement. This is the reason why a joint ○ The primary function of a joint is to all
exists in the first place. ○ The The movement ent that occurs at a joint oint is is created created by muscl muscles es.
The The role of a muscle contraction ion is actually to create a for force on the bones of a join jointt; that force can create movement ent at at the joint. oint. Howeve However, r, the force of the muscle uscle contracti contraction on can also stop or modify movement. ○ L igaments and and joi joint nt capsu capsulles functi function on to li limit excessive ssive movem ovement at a joint. oint. ○ J oints oints allow m movem ovement. ○ Muscles create m movem ovement. ○ L igaments/joi nts/joint nt caps capsul ule es limit m movem ovement. ○ I n additi addition on to allowing owing movem ovement to occur, occur, joints oints ha have 3 characteristi ri stics: cs:
aring: Many joints of the body are weight-bearing joints—that is, they bear ○ Weight bearing
the weight weight of the body body parts parts locate located above them. Al A lmost every every joi joint nt of the the lower extr extrem emity and all the spinal joi j oints nts of the axia xial body body are weightght-be bearing ri ng joints. oints. As As arule rule, weight weight-bearing aring joi joints nts need need to be very stable stable to support support the wei weight that that is is borne through th them em. orption: J oints ○ Shock absorption oints can can func functi tion on to to abs absorb orb shoc shock. k. This his is is esp espe ecia cially im importan portantt for for
weight-bearing joints. The primary means by which a joint absorbs shock is the cushioning effect of the fluid within the joint cavity. ○ Stability: Even though the primary function of a joint is to allow motion to occur,
excessive motion would create an unstable joint. Therefore a joint must be sufficiently stable that it does not lose its integrity and become injured or dislocated. ○ Each joint of the body finds a balance between mobility and stability. ○ Mobil M obiliity and and sta stabil biliity are are anta antagoni gonistic stic properti ropertie es: A more mobi obile joint joint is is le less sta stable; ble; a
more stable joint is less mobile.
Join Jointt Mob Mobili ility Vs. Joi Joint Stab tability lity ○ By definition, a joint is mobile. However, a joint must also be sufficiently stable so that it
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○ Every joi j oint nt of the body body fi finds a balance be between mobility and stability. ○ The more mobile a joint is, the less stable it is. ○ The price price to pay for greater ter mobi obility is less stabili bil ity. ○ L ess stabil bility means a joint oint has a grea greater ter chance chance for injury. njury. ○ The more stable a joint is, the less mobile it is. ○ The price price to pay for greater ter stabili bil ity is less mobi obility. ○ L ess ess mobil obility means that a joint oint has has a decreas decreased ed ability to move and pla place body
parts in certain positions. ○ Therefore mobility and stability are antagonistic concepts; more of one means less of the
other! The The follo follow wing ing are three major jor fac factors that determine ine the balan lance of mobility ility and stability ility of a joint: ○ The sha shape pe of the bones of the joi joint nt ○ The ligament/joi nt/joint nt capsul psule e com comple plex of the joint oint (Note (Note:: L igaments and joi joint nt caps capsul ule es are are
both made up of the sam same fibrous material ri al,, and both act to li limit motion otion of a joint; oint; therefore therefore they can can be grouped grouped together as theligament/ ent/jjoint oint capsul capsule e complex.) plex.)
Now compare the 2 joints : Shoulder and hip. Use the different terms: Deep socket, ocket, shall ow socke socket, t, mobil mobi l i ty, stabil i ty, l i gaments, gaments, mus muscl cles es
______________ _____________________ ______________ ______________ _____________ _____________ ______________ ______________ __________ ___ ______________ _____________________ ______________ ______________ _____________ _____________ ______________ ______________ __________ ___ ______________ _____________________ ______________ ______________ _____________ _____________ ______________ ______________ __________ ___ ______________ _____________________ ______________ ______________ _____________ _____________ ______________ _________________ __________ ______________ _____________________ ______________ ______________ _____________ _____________ ______________ ______________ __________ ___
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Synovial Joints Structurally, synovial joints are the most complicated joints of the body. The They are also lso the join jointts that most people think of when they think of joints. The wrist, elbow, shoulder, ankle, knee, and hip joints are a few examples of synovial joints.
Components of a Synovial Joint ○ The bones of a synovial joint are connected by a joint capsule, which encloses a joint
cavity. ○ This joint capsule is composed of 2 distinct layers:
vial membrane layer. (1) an outer fibrous layer and (2) an inner synovial ○ The inner synovial membrane layer secretes synovial flui fluid d into the joint cavity, also
cavity. known known as the synovial cavity. tilage (i.e., ○ Furthermo Furthermore, re, the articul articula ar ends of the bones bones are cappe capped with with articular cartilag
hyaline cartilage). ○ Synovial joints are the only joints of the body that possess a joint cavity. ○ By virtue of the presence of a joint cavity, synovial joints typically allow a great deal of
movement.
Ty Types of synovial ial join jointt
• GLIDING • HINGE • PIVOTING • CONDYLOID • SADDLE • BALL AND SOCKET
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Menisci and Articular Discs ○ Most often, often, the bone bones s of a joint oint have have opposi opposing ng surf surface aces that that are congruent (i.e., their
surface surfaces match match each other). other). However, owever, sometim etimes the the surf surface aces of the bone bones s of a joi joint nt are not well matched. tched. In I n the these case cases s the joint oint wil will ofte often n have an add addiitiona tional intra-articul ntra-articula ar structure interposed between the two bones. ○ These additional intra-articular structures are made of fibrocartilage and function to help
maximize the congruence of the joint by helping to improve the fit of the two bones. ○ By improving the congruence of a joint, these structures help to do two things: ○ Mai Maintain ntain norm normal joi j oint nt movements: ents: Beca Because of the better fi fit between tween the two bones bones of
the joi joint, nt, these these structures hel help to im improve the movement ent of the two bones relati relative ve to each other. ○ Cushion the joint: These structures help to cushion the joint by absorbing and
transmitting forces (e.g., weight bearing, shock absorption) from the bone of one body part to the bone of of the next body part. rt. ○ I f this fi fibrocartil rtilaginous structu structure re is is ring ring sha shaped, it it is is called an an articular disc. ○ I f it is is cresce crescent sha shaped, it i t is is cal called a meniscus (plural: menisci) ○ A lthough though these these structures structures are are in in contact with wi th the articul rticula ar surfa surfaces ces of
the joints, they are not attached to the joint surfaces but rather to adjacent soft tissue of the capsule or to bone adjacent to the articular surface. ○ Articular discs are found in many joints of the body. ○ One example ple is thetem temporomandibula ndibular joi joint nt (TM (TMJ ), which which has an
articular disc located within its joint cavity. ○ Anothe A nother exam example ple is the the sternocla rnoclavicul vicula ar joi joint, nt, which which has an an
articular disc located within its join jointt cavity ity. ticular me menisci are found ○ Articular
between the tibi tibia a and the fem femur in in the knee joint
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