EAMC Orthopedics

7/26/2019 EAMC Orthopedics

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Orthopedic/Trauma patient history and physical examinationComplete Orthopedic DiagnosisDermatomes, Myotomes (Cervical to Sacral)





Inammatory Mediators (!! path"ay)



#ain Medications commonly used in Orthopedics$ustilo and !nderson Classi%cation o& Open 'racturesSalterarris Classi%cationDo*s and Don*ts in Ta+ing adiographs

-rachial #lexus The .rachial plexus is &ormed in the posterior triangle o& the nec+ .y the union o& the anterior rami o& the th, 0th, 1th, and 2th cervical and the %rst thoracic spinalnerves ('ig3 44314)3 This plexus is divided into roots, trun+s, divisions, and cords3

The roots o& C and 0 unite to &orm the upper trun+, the root o& C1 continues as the

middle trun+, and the roots o& C2 and T4 unite to &orm the lo"er trun+3 5ach trun+then divides into anterior and posterior divisions3 The anterior divisions o& the upperand middle trun+s unite to &orm the lateral cord, the anterior division o& the lo"ertrun+ continues as the medial cord, and the posterior divisions o& all three trun+s

6oin to &orm the posterior cord3

The roots o& the .rachial plexus enter the .ase o& the nec+ .et"een the scalenusanterior and the scalenus medius muscles ('ig3 4431)3 The trun+s and divisionscross the posterior triangle o& the nec+, and the cords .ecome arranged around theaxillary artery in the axilla (see 'ig3 7389)3 ere, the .rachial plexus and the axillaryartery and vein are enclosed in the axillary sheath3



-rachial #lexus The nerves entering the upper lim. provide the &ollo"ing important &unctions:sensory innervation to the s+in and deep structures, such as the 6oints; motorinnervation to the muscles; inuence over the diameters o& the .lood vessels .y thesympathetic vasomotor nerves; and sympathetic secretomotor supply to the s"eatglands3

!t the root o& the nec+, the nerves &orm a complicated plexus called the .rachialplexus3 This allo"s the nerve %.ers derived &rom di<erent segments o& the spinal

cord to .e arranged and distri.uted e=ciently in di<erent nerve trun+s to thevarious parts o& the upper lim.3 The .rachial plexus is &ormed in the posteriortriangle o& the nec+ .y the union o& the anterior rami o& the th, 0th, 1th, and 2thcervical and the 4st thoracic spinal nerves ('igs3 7342 and 7347)3

The plexus can .e divided into roots, trun+s, divisions, and cords ('ig3 7342)3 Theroots o& C and 0 unite to &orm the upper trun+, the root o& C1 continues as themiddle trun+, and the roots o& C2 and T4 unite to &orm the lo"er trun+3 5ach trun+then divides into anterior and posterior divisions3 The anterior divisions o& the upperand middle trun+s unite to &orm the lateral cord, the anterior division o& the lo"ertrun+ continues as the medial cord, and the posterior divisions o& all three trun+s

6oin to &orm the posterior cord3

The roots, trun+s, and divisions o& the .rachial plexus reside in the lo"er part o& theposterior triangle o& the nec+ and are &ully descri.ed on page >>>3 The cords.ecome arranged around the axillary artery in the axilla ('ig3 734)3 ere, the.rachial plexus and the axillary artery and vein are enclosed in the axillary sheath3

Cords o& the -rachial #lexus !ll three cords o& the .rachial plexus lie a.ove andlateral to the %rst part o& the axillary artery ('igs3 734 and 7389)3 The medial cord



crosses .ehind the artery to reach the medial side o& the second part o& the artery('ig3 7389)3 The posterior cord lies .ehind the second part o& the artery, and thelateral cord lies on the lateral side o& the second part o& the artery ('ig3 7389)3 Thus,the cords o& the plexus have the relationship to the second part o& the axillary arterythat is indicated .y their names3

Most .ranches o& the cords that &orm the main nerve trun+s o& the upper lim.continue this relationship to the artery in its third part ('ig3 7389)3

The .ranches o& the di<erent parts o& the .rachial plexus ('igs3 7347 and 7384) areas &ollo"s:ootsDorsal scapular nerve (C)?ong thoracic nerve (C, 0, and 1)

@pper trun+Aerve to su.clavius (C and 0)Suprascapular nerve (supplies the supraspinatus and in&raspinatus muscles)

?ateral cord?ateral pectoral nerveMusculocutaneous nerve?ateral root o& median nerve

Medial cordMedial pectoral nerveMedial cutaneous nerve o& arm and medial cutaneous nerve o& &orearm@lnar nerveMedial root o& median nerve

#osterior cord@pper and lo"er su.scapular nerves

Thoracodorsal nerve!xillary nerveadial nerve

-ranches o& the -rachial #lexus 'ound in the !xilla The nerve to the su.clavius (C and 0) supplies the su.clavius muscle ('igs3 734,7347, and 7389)3 It is important clinically .ecause it may give a contri.ution (C) tothe phrenic nerve; this .ranch, "hen present, is re&erred to as the accessory phrenicnerve3

The long thoracic nerve (C, 0, and 1) arises &rom the roots o& the .rachial plexus inthe nec+ and enters the axilla .y passing do"n over the lateral .order o& the 4st ri..ehind the axillary vessels and .rachial plexus ('igs3 734 and 7347)3 It descendsover the lateral sur&ace o& the serratus anterior muscle, "hich it supplies3

The lateral pectoral nerve arises &rom the lateral cord o& the .rachial plexus andsupplies the pectoralis ma6or muscle ('igs3 734B and 7389)3



The musculocutaneous nerve arises &rom the lateral cord o& the .rachial plexus,supplies the coraco.rachialis muscle, and leaves the axilla .y piercing that muscle('igs3 734B and 7389)3 ! summary o& the complete distri.ution o& themusculocutaneous nerve is given in 'igure 73883

The lateral root o& the median nerve is the direct continuation o& the lateral cord o&

the .rachial plexus ('igs3 734B and 7347)3 It is 6oined .y the medial root to &orm themedian nerve trun+, and this passes do"n"ard on the lateral side o& the axillaryartery3 The median nerve gives o< no .ranches in the axilla3

The medial pectoral nerve arises &rom the medial cord o& the .rachial plexus,supplies and pierces the pectoralis minor muscle, and supplies the pectoralis ma6ormuscle ('ig3 7347)3

The medial cutaneous nerve o& the arm (T4) arises &rom the medial cord o& the.rachial plexus ('igs3 7348 and 7389) and is 6oined .y the intercosto.rachial nerve(lateral cutaneous .ranch o& the 8nd intercostal nerve)3 It supplies the s+in on themedial side o& the arm3

The medial cutaneous nerve o& the &orearm arises &rom the medial cord o& the.rachial plexus and descends in &ront o& the axillary artery ('ig3 7389)3 cord o& the.rachial plexus and descends in the interval .et"een the axillary artery and vein('igs3 734B and 7389)3

The ulnar nerve gives o< no .ranches in the axilla3 ! summary o& the completedistri.ution o& the ulnar nerve is given in 'igure 738B3

The medial root o& the median nerve arises &rom the medial cord o& the .rachialplexus and crosses in &ront o& the third part o& the axillary artery to 6oin the lateralroot o& the median nerve ('igs3 734B and 7389)3 ! summary diagram o& the completedistri.ution o& the median nerve is given in 'igure 73883

The upper and lo"er su.scapular nerves arise &rom the posterior cord o& the.rachial plexus and supply the upper and lo"er parts o& the su.scapularis muscle3In addition, the lo"er su.scapular nerve supplies the teres muscle ('igs3 734 and7347)3

The thoracodorsal nerve arises &rom the posterior cord o& the .rachial plexus andruns do"n"ard to supply the latissimus dorsi muscle ('igs3 734 and 7347)3

The axillary nerve is one o& the terminal .ranches o& the posterior cord o& the.rachial plexus ('igs3 734and 7347)3 It turns .ac+"ard and passes through the uadrangular space (see pageB04)3 aving given o< a .ranch to the shoulder 6oint, it divides into anterior andposterior .ranches (see page B04)3 ! summary o& the complete distri.ution o& theaxillary nerve is given in 'igure 7383

The radial nerve is the largest .ranch o& the .rachial plexus and lies .ehind theaxillary artery ('igs3 734, 7347, and 7389)3 It gives o< .ranches to the long and themedial heads o& the triceps muscle and the posterior cutaneous nerve o& the arm('ig3 734B)3 The latter .ranch is distri.uted to the s+in on the middle o& the .ac+ o&



the arm3 ! summary o& the complete distri.ution o& the radial nerve is given in'igure 7383





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EAMC Orthopedics