kinesiology of shoulder complex

8/18/2019 Kinesiology of Shoulder Complex

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Alya Putri Khairani / 130110110220

Kinesiology of Shoulder Complex: muscles of the shoulder region

he muscles of the shoulder region gi!e "xation to and produce mo!ements of the shoulder girdle and controlScapulohumeral relationships# he muscles of the shoulder girdle also participate signi"cantly in s$illedmo!ements of the upper extremity% such as &riting% and are essential in acti!ities re'uiring pulling% pushing% andthro&ing% to mention only a fe& of the important acti!ities of the upper extremity

he shoulder region muscles are di!ided into three groups for study:

• (uscles connecting the shoulder girdle &ith the trun$% the nec$% and the s$ull

• (uscles connecting the Scapula and the )umerus• (uscles connecting the trun$ and the )umerus% ha!ing little or no attachment to the Scapula

Muscles from Trunk to Shoulder Girdle

Serratus Anterior

Trapezius

Rhomboid Major and Minor

Pectoralis Minor

Proximal attachment:*y four tendomuscular slips from the second to the "fth ri+s

Proximal attachment:*y nine muscular slips from the anterolateral aspect of the thorax%from the "rst to the ninth ri+s,hence its name% the -sa& muscle#- helo&est four or "!e slips interdigitate &ith the external o+li'uea+dominal muscle

.istal attachment: he muscle passes underneath the Scapula &ith the distal attachmentoccurring along the medial +order of the Scapula# he lo&est "!edigitations con!erge on the inferior angle of the Scapula% attaching toits costal surface# his is the strongest portion of the muscle

nner!ation:ong thoracic ner!e CS,C

Anatomic actions:A+duction and up&ard rotation of the Scapula

Proximal attachment:

4ccipital +one% igamentum 5uchae% and Spinous Processes from C 6 12.istal attachment: he muscle "+ers con!erge to their distal attachments#on the Acromial end ofthe Cla!icle% the Acromion% and the Spine of the Scapula

nner!ation:Spinal accessory ner!e C1 6 C7 and spinal portion of Cranial 5er!e 8

Anatomic actions: he Upper Trapezius performs ele!ation and up&ard rotation of the scapula%as &ell as extension% lateral 9exion% and contralateral rotation of the nec$ theLower Trapezius performs up&ard rotation% adduction% and depression of thescapula the middle trape;ius performs up&ard rotation and adduction of thescapula

Connect the Scapula &ith the !erte+ral column% lie underneath the rape;ius# he upper portion is$no&n as


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.istal attachment: he proximal attachment slips con!erge &ith their distal attachment into the Coracoid Process of theScapula# his gi!es the muscle a triangular shape

nner!ation:(edial Pectoral 5er!e C 6 1

Anatomic actions:.epression and !entral tilt of the scapula as &ell as ele!ation of ri+s 2 to >

Levator Scapulae

Muscles from Shoulder Girdle to Humerus

Deltoid

Supraspinatus

Infraspinatus and Teres Minor

Proximal attachment:nfraspinous fossa and lateral +order of the scapula# he infraspinatus lies closest to the spine of the scapulaand occupies most of the infraspinous fossa# he teres minor is attached mainly to the lateral +order of thescapula

.istal attachment:

Proximal attachment: rans!erse processes of the upper cer!ical !erte+rae

.istal attachment:(edial +order of the Scapula% a+o!e the spine% near the superior angle

nner!ation:.orsal Scapular 5er!e C3 6 C>

Anatomic actions:?le!ation and do&n&ard rotation of the Scapula as &ell as ateral @lexionand psilateral rotation of the Cer!ical spine

A large super"cial muscle consisting of three parts: anterior%middle% and posterior# he muscle co!ers the lenohumeral =ointon all sides except the axilla and comprises 70 percent of themass of the Scapulohumeral musclesProximal attachment:

he acromial end of the Cla!icle% the Acromion process% andthe spine of the Scapula

.istal attachment: hree portions of the muscle con!erge to ha!e their distalattachment onto the deltoid tu+erosity% a rather rough areaa+out half&ay do&n the shaft of the humerus

nner!ation:Axillary 5er!eC> 6 CB

Anatomic actions:A+duction of the lenohumeral =oint# Anterior .eltoidperforms 9exion and hori;ontal adduction of thelenohumeral =oint# Posterior .eltoid performs extension and


Supraspinous fossa of the scapula% &hich it completely "lls# he muscle"+ers con!erge to&ard the tip of the shoulder to form a short tendon thatpasses underneath the acromion and that adheres to the capsule of theshoulder =oint

.istal attachment:ppermost facet of the reater u+ercle of the )umerus

nner!ation:Supracapsular ner!e C> 6 CB

Anatomic actions:A+duction of the lenohumeral oint


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Subcapsularis

Teres Major

Coracobrachialis

iceps rachii and Triceps rachii

he *iceps and riceps muscles do not +elong to the Scapulohumeral group +ecause they do not ha!e their distalattachments on the )umerus ho&e!er% the t&o heads of the *iceps and the long head of the riceps cross theshoulder =oint and therefore act on it# he *iceps is a 9exor and an a+ductor% and the riceps is an extensor and anadductor of the lenohumeral =oint# he long head of the *iceps is capa+le of ele!ating the arm &hen the .eltoidand the Supraspinatus are paraly;ed# he motionoccurs in a position of external rotation of the

reater tu+ercle of the humerus% infraspinatus into its middle facet%and teres minor into its lo&er posterior facet# he tendons of +othmuscles are adherent to the capsule

nner!ation:nfraspinatus +y the suprascapular ner!e and teres minor +y theaxillary ner!e CS,CB#

Anatomic actions:

Proximal attachment:Costal surface of Scapula# @i+er +undles con!erge to&ard the axilla toform a +road tendon% &hich passes o!er the anterior aspect of thecapsule of the lenohumeral =oint

.istal attachment:esser tu+ercle of the humerus and shaft +elo& the tu+erclenner!ation:

Su+capsular ner!e C> 6 CBAnatomic actions:

n&ard rotation of the lenohumeral =oint# .epending on the armosition the Su+sca ularis can 9ex extend adduct or a+duct the

Proximal attachment:nferior angle of the scapula

.istal attachment: he muscle "+ers course up&ard and laterally and ha!e their distalattachments to the crest of the lesser tu+ercle of the humerus +y means ofa strong +road tendon

nner!ation:Su+capsular ner!e C> 6 CB

Anatomic actions:nternal rotation adduction and extension of the lenohumeral oint


Coracoid process of Scapula.istal attachment:

(edial surface of humerus% a+out half&ay do&n the shaft of thehumerus

nner!ation:(usculocutaneous ner!e CB,C

Anatomic actions:nternal rotation% adduction% and extension of the lenohumeral =oint


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D

Muscles from Trunk to Humerus

Latissimus Dorsi

Pectoralis Major

Support and Dynamic Stabilization of the Shoulder

Rotator Cu! Stabilization

Ehen a person is carrying a hea!y load such as a +riefcase in the hand% ?( acti!ity has +een found in thehori;ontally directed rotator cuF muscles,the Supraspinatus% nfraspinatus% and eres (inor# Contraction of thesemuscles holds the )umeral/head tightly against the lenoid to pre!ent su+luxation &hen carrying a &eight in thehand

iceps rachii

he tendon of the long head of the *iceps *rachii courses o!er the )umeral head and descends in thentertu+ercular groo!e# Ehen the muscle contracts tension occurs in the tendon to produce a do&n&ard andin&ard force on the head of the )umerus% compressing it against the lenoid ca!ity# his force is similar to pullinga rope around a post# hus% &hen the el+o& is 9exed &ith a G&eight in theG hand% the +iceps aids in pre!entingsu+luxation of the lenohumeral =oint

The Deltoid

Attention has +een focused on the deltoid in its function as an a+ductor of the glenohumeral =oint# n the early partof ele!ation% the ma=or force of the deltoid is directed !ertically% producing a shear on the glenoid and causing thehumeral head to stri$e the coracoacromial arch% %his mo!ement is pre!ented +y the hori;ontal and do&n&ardlines of action of the rotator cuF muscles# Some consider the posterior deltoid itself to +e an adductor or to cause

lenohumeral =oint% slightly anterior to the frontal plane and &ithoutresistance or a tool in the hand# his motion is useful for placement of thehand o!er the head% +ut the long head of the *iceps is not strong enough tolift o+ ects or to erform &or$ in this osition

Proximal attachment:Spinous processes of the thoracic !erte+rae from ,B do&n&ard%.orsolum+ar fascia% Crest of lium posterior portion% and the lo&estri+s% here interdigitating &ith the ?xternal 4+li'ue A+dominal muscle#

he "+ers con!erge to&ard the Axilla% some "+ers passing o!er or

near the inferior angle of the Scapula% often adhering to it.istal attachment:

A tendon that courses in the axilla and attaches to the crest of thelesser tu+ercle of the humerus% proximal to that of the teres ma=or#

nner!ation: horacodorsal ner!e CB,CS

Anatomic actions:nternal rotation% extension and adduction of the glenohumeral =oint%scapular depression% ele!ation of pel!is#


Cla!icle sternal half% sternum% and costal cartilages of the second tose!enth ri+s% and the aponeurosis o!er the a+dominal muscles# hemuscle is descri+ed as consisting of three parts: the cla!icular%sternocostal% and a+dominal

.istal attachment:Crest of the greater tu+erosity of the humerus% on an area se!eral incheslong# *efore reaching its attachment% the tendon +ridges theintertu+ercular +icipital groo!e

nner!ation:(edial and ateral Pectoral ner!e C> 6 1

Anatomic actions:Adduction and internal rotation of the lenohumeral oint# Cla!icular


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=oint compression in the early part of the inotion and ha!e found lines of force inferior or !ery close to the axis ofmotion# As ele!ation progresses% the le!er arms for a+duction increase% +ut most of the force generated +y thedeltoid is directed into the sta+ili;ing component &hich compresses the head of the humerus against the glenoid#n the position of arm ele!ation% the deltoid and the

Synergistic Muscle Action

n the many motion com+inations% muscles or their parts can +e classi"ed as synergists or antagonistsfor aparticular mo!ement only# ?xamples are the rape;ius and the Serratus Anterior as they act together to produceup&ard rotation of the scapula +ut act as antagonists in retraction and protraction of the scapula# ?!en the parts of the, same muscle may act as #synergists or antagonists as occurs &ith the trape;ius# he upper and lo&ertrape;ius act synchro nously in up&ard rotation of the scapula +ut are antagonists in ele!ation and depression ofthe scapula# Se!eral important synergies% or force couples% occur in the shoulder# n mechanics% a force couple isde"ned as t&o forces &hose points of application occur on opposite sides of an axis and in opposite directions toproduce rotation of the +ody# his situation occurs during ele!ation of the arm# he trape;ius and the serratusanterior com+ine forces to produce a+duction and up&ard rotation of the scapula# he deltoid and the Suprespintuscontract together to produce a+duction or 9exion at the lenohumeral =oint

Motion and Muscular Activity in Function

Muscles of Scapulothoracic "oint

?le!ation

hori;ontal forces of the rotator cuF muscles pro!ide sta+ilityfor the glenohumerai =oint# n full shoulder ele!ation as inpressing up&ard or standing on the hands% the a+ductedand up&ardly rotated scapula forms a platform for the headof the humerus# he scapula% in turn% is sta+ili;ed +y theserratus anterior and the trape;ius muscles

(A) nitiation of a+duction(B) At H0I of lenohumeral a+duction# he solid lines representthe medial or anterior lines of action of the middle .eltoid .%Supraspinatus Sup% and the Su+scapularis Su+ the dotted

lines represent the posterior lines of action of the nfraspinatusS and the eres (inor min# he !ector of the deltoid has+een resol!ed into a rotar com onent .


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Alya Putri Khairani / 130110110220 he muscles that responsi+le for ele!ation of the Scapula and Cla!icle are pper rape;iues% e!ator Scapulae%and to a lesser extent%


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Pushin$

Thro%in$

he o!erhead thro&ing motion is found in many types of athletics +ase+all% foot+all% rac'uet sports% gymnastics%

=a!elin% and s&imming# *oth the acceleration and deceleration phases fre'uently lead to in=uries of the lenoida+rum and the to inches using scapular depression alone# n the&eight,+earing phases of crutch,&al$ing% the muscle acti!ity issimilar to the sitting push,up: riceps *rachii% Pectoralis (a=or%

kinesiology of shoulder complex

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