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  #1  
Old 09-02-2011
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Anatomy Which Brachial Plexus Cord!

A 55-year-old male presents to your office complaining of 1st web space muscle atrophy and decreased sensation of the medial forearm. An astute musculoskeletal examination reveals that his radial pulse disappears with abduction and external rotation of his shoulder when his head is turned to the contralateral side. Which cord of the brachial plexus has likely been affected?
A. Lateral
B. Posterior
C. Superior
D. Inferior
E. Medial
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Old 09-02-2011
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B . posterior cord
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A 55-year-old male presents to your office complaining of 1st web space muscle atrophy and decreased sensation of the medial forearm. An astute musculoskeletal examination reveals that his radial pulse disappears with abduction and external rotation of his shoulder when his head is turned to the contralateral side. Which cord of the brachial plexus has likely been affected?
A. Lateral
B. Posterior
C. Superior
D. Inferior
E. Medial

It's a case of Cervical Rib Syndrome
Here
in Adson's test head is turned towards opposite side( In Scalelne Anticus Syndrome it is turned towards the affected side)
Due to subclavian artery compression there is radial pulse disappearance and due to Medial cord( Medial antebrachial cutaneus) compression loss of sensation on medial side of forearm.
1 st webspace atrophy , don't know WHY???

Last edited by drnrpatel; 09-02-2011 at 06:56 PM.
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Old 09-02-2011
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IT IS NOT............CERVICAL RIB SYNDROME......................IT IS KLUMPKE'S PALSY,,,,,,,,,,,,,,,,,PULSE DISAPPEARING ON MOVING HEAD TO CONTRALATERAL
SIDE IS CHARACTERISTIC OF kLUMPKE'S PALSY AND PULSE DISAPPEARING ON SAME SIDE IS THAT OF THORACIC OUTLET SYNDROME..........IN WHICH LOWER TRUNK OF THE BRACHIAL PLEXUS IS EFFECTED..........HOWEVER........THEY HAVE ASKED ABOUT THE CORD HERE...........THOUGH i AGREE IT IS MEDIAL CORD
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Quote:
Originally Posted by Crimsonboy View Post
IT IS NOT............CERVICAL RIB SYNDROME......................IT IS KLUMPKE'S PALSY,,,,,,,,,,,,,,,,,PULSE DISAPPEARING ON MOVING HEAD TO CONTRALATERAL
SIDE IS CHARACTERISTIC OF kLUMPKE'S PALSY AND PULSE DISAPPEARING ON SAME SIDE IS THAT OF THORACIC OUTLET SYNDROME..........IN WHICH LOWER TRUNK OF THE BRACHIAL PLEXUS IS EFFECTED..........HOWEVER........THEY HAVE ASKED ABOUT THE CORD HERE...........THOUGH i AGREE IT IS MEDIAL CORD

Yeah, that makes sense... thanx...
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Old 09-02-2011
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it is thoracic outlet syndrome due to cervical rib. inferior trunk. medial cord,
klumpke is just inferior trunk lesion due to traction or shoulder dystocia during delivery. with claw hand
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Old 09-02-2011
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it sounds like adson's sign but in that sign, u make the person look towards the same side of the arm streched outwards, and it sounds like there is thoracicc outlet syndrome where both nerves and arteries are affected!
so my ans is also E!.. median nerve coming out of it affecting medial aspect of the forearm and also 1st web supplied by median nerve!
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Old 09-03-2011
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Quote:
Originally Posted by salz View Post
it sounds like adson's sign but in that sign, u make the person look towards the same side of the arm streched outwards, and it sounds like there is thoracicc outlet syndrome where both nerves and arteries are affected!
so my ans is also E!.. median nerve coming out of it affecting medial aspect of the forearm and also 1st web supplied by median nerve!
i think it;s more ulnar nerve involvement
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Quote:
Originally Posted by dr_lizard View Post
i think it;s more ulnar nerve involvement
if ulnar nerve is involved then sensory loss will be 5th web not 1st
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Old 09-03-2011
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Quote:
Originally Posted by salz View Post
if ulnar nerve is involved then sensory loss will be 5th web not 1st
1st web space => muscle atrophy (not sensory loss)
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Old 09-03-2011
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medial cord
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Old 09-03-2011
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Its a typical case of Thoracic outlet syndrome
Involvement of Medial nerve => Atrophy of muscles of 1st web space of palm
And skin of Medial forearm => Medial Antebrachial cutaneous nerve
Both branches of Medial cord.
So Medial cord is the answer
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Old 09-04-2011
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The correct answer is E.
The physical exam findings suggests thoracic outlet syndrome, wherein the brachial plexus is compressed by elements of the thoracic skeleton. This syndrome most commonly affects the inferior brachial plexus (C8-T1). This causes atrophy of muscles that are innervated by the ulnar nerve, as well as loss of sensation on the medial side of the forearm. In this patient, the finding of 1st webspace atrophy indicates atrophy of the interosseus muscle; all interosseus muscles of the hand are innervated by the deep branch of the ulnar nerve.

The ulnar nerve originates from the medial cord of the brachial plexus
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