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79 Cards in this Set
- Front
- Back
The brachial plexus nerve fibers pass through which triangle of the neck?
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Posterior cervical triangle
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The brachial plexus nerve fibers pass in between which two muscles?
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Anterior and middle scalene muscles
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What type of nerve fibers are found in the brachial plexus?
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Somatic Afferent
Somatic Efferent Visceral Afferent Visceral Efferent |
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How is the brachial plexus divided?
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(from proximal to distal:)
Roots Trunks Division Cords Branches |
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In general, the shoulder and proximal limb is innervated from the _______ (upper/lower) roots of the brachial pluxus.
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Upper
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Lesions involving the C5 or C6 spinal cord or nerve roots will be seen as problems in which regions of the upper limb?
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Scapula and shoulder
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Lesions involving C8 or T1 will be expressed as weakness or problems in which region of the upper limb?
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Hand
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What are the roots of the brachial plexus composed of?
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Ventral primary rami of spinal nerves C5, C6, C7, C8, T1
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List 2 nerves that branch from the roots of the brachial plexus.
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1. Dorsal scapular N (C5) --> levator scapulae, rhomboid major/minor
2. Long thoracic N (C5-C7)--> serratus anterior |
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Name the 3 trunks of the brachial plexus.
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1. Upper
2. Middle 3. Lower |
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Which nerve roots form the upper trunk?
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C5 and C6 nerve roots
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Which nerve root forms the middle trunk?
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Direct continuation of the C7 nerve root
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Which nerve roots form the lower trunk?
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C8 and T1
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T or F.
The upper trunk is the only trunk to give off nerves. |
TRUE.
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Name the 2 branches of the upper trunk.
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1. Suprascapular N (C5-C6) --> Supraspinatus and infraspinatus
2. Nerve to subclavius (C5-C6) |
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Which nerve runs laterally across the posterior cervical triangle to pass through the scapular notch under the suprascapular ligament?
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Suprascapular N (C5-6)
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T or F.
Several nerves originate from the middle and lower trunks of the brachial plexus. |
FALSE
Only the upper trunk gives off nerve branches |
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T or F.
No nerves originate from the divisions of the brachial plexus. |
TRUE.
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How many divisions are there?
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3 anterior and 3 posterior divisions
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The anterior divisions of the upper trunk and the middle trunk join to form the _____ cord.
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Lateral cord
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The anterior division of the lower trunk continues as the _______ cord.
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Medial cord
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The 3 posterior divisions come together to produce the ______ cord.
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Posterior cord
*Lead to the formation of the postaxial nerves of the limb |
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T or F.
The lower trunk has a small and variable contribution to the posterior cord. |
TRUE.
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The Lateral pectoral N (C5-C7) is a branch off of which cord?
What muscle does it innervate? |
Lateral cord
Innervates the Pectoralis major M. |
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Name the 2 terminal branches of the lateral cord.
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1. Musculocutaneous N
2. Median N (contribution) |
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Which nerve passes through the fibers of the coracobrachialis and terminates as the lateral cutaneous nerve of the forearm?
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Musculocutaneous N (C5-6)
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Which specific nerve fibers does the lateral cord contribute to the formation of the Median N?
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C6 and C7 fibers
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Name 3 non-terminal branches of the Medial cord.
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1. Medial Pectoral N (C8-T1) --> Pectoralis major and minor
2. Medial brachial cutaneous N (C8-T1) --> innervates skin on medial side of arm 3. Medial Antebrachial cutaneous N (C8-T1) --> innervates skin on medial side of forearm down toward wrist |
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Which nerve innervates the skin o nthe medial side of the arm?
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Medial brachial cutaneous N
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Which nerve innervates the skin on the medial side of the forearm down toward the wrist?
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Medial antebrachial cutaneous N
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Name the terminal branches of the Medial cord?
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1. Ulnar N (C8-T1)
2. Median head of the Median N (C8-T1) |
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Which cord gives off several branches that innervate the muscles of the posterior axillary fold?
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Posterior cord
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Name 3 non-terminal branches of the posterior cord.
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1. Upper subscapular N (C5-C6) --> upper portion of Subscapularis
2. Lower subscapular N (C5-6C6) --> lower portion of Subscapularis and teres major 3. Thoracodorsal N (C7-C8) --> Latissimus dorsi |
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Name the terminal branches of the posterior cord.
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1. Axillary N
2. Radial N |
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Which artery accompanies the Axillary N as it passes through the quadrangular space?
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Posterior humeral circumflex A
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Which muscles does the Axillary N innervate?
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1. Deltoid
2. Teres minor |
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Which nerve innervates the Coracobrachialis, biceps brachii, and brachialis muscles?
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Musculocutaneous N
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Which nerve supplies the skin on the lateral side of the forearm?
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Lateral antebrachial cutaneous N
(continuation of the musculocutaneous N) |
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T or F.
The Median N innervates some muscles in the arm. |
FALSE
It supplies most of the flexors of the forearm. |
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The Median N supplies all of the flexors of the forearm and wrist EXCEPT for 2 1/2. List these exceptions.
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1. Flexor carpi ulnaris
2. Ulnar half of the flexor digitorum profundus 3. Brachioradialis |
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Describe the course of the Median N as it passes through the Median tunnel.
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It passes the biceps tendon, then passes through the two heads of the pronator teres and the two heads of the flexor digitorum superficialis muscle.
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Which nerve passes through the carpal tunnel between the flexor retinaculum and the flexor digitorum superficialis muscle?
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Median N
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List the structures that the Median N innervates.
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1. 3 muscles of the thenar eminence
2. Lateral two lumbrical muscles 3. Skin of the palm 4. Skin of the lateral 3 1/2 digits (as well as the dorsal aspect of these fingers past the distal interphalangeal joint) |
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Which cervical spinal nerves make up the musculocutaneous N?
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C5-C7
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Which cervical spinal nerves make up the Median N?
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C5-T1
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Which cervical spinal nerves make up the radial N?
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C5-T1
(but mostly C6, C7, and a little from C8) |
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Which nerve is the largest terminal branch of the brachial plexus?
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Radial N
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Which nerve travels posteriorly throug hthe triceps muscle separating the lateral head from the medial head and travels in the spiral groove of the humerus?
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Radial N
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Name the 2 branches of the Radial N.
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Deep branch
Superficial branch |
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The deep branch of the Radial N enters the _________ (anterior/posterior) compartment of the forearm as the _________ nerve.
What does this nerve innervate? |
Posterior compartment
Posterior interosseous N Innervates extensors of the forearm and wrist |
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What does the superficial branch of the Radial N innervate and which compartment of the forearm is it found in?
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Innervates the skin of the radial side of the hand and 1/2 digits over the proximal to middle phalanx.
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Which nerve passes through the scapular notch under the suprascapular (transverse scapular) ligament?
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Suprascapular N
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What tunnel is formed by the two heads of the flexor carpi ulnaris muscle, and which nerve passes through this tunnel?
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Ulnar tunnel
Ulnar N |
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Which muscles does the Ulnar N innervate in the forearm?
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1. Flexor carpi ulnaris M
2. Ulnar half of the flexor digitorum profundus |
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Which muscles does the deep branch of the Ulnar N innervate?
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1. Hypothenar muscles
2. Medial two lumbricals 3. All of the interosseous muscles 4. Adductor pollicis M 5. Deep head of flexor pollicis brevis M (usually) *Ulnar N innervates all the muscles in the hand except for the thenar muscles and the lateral two lumbricals, which are innervated by the Median N. |
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Which nerve innervates the palmaris brevis and the skin over the palmar and dorsal surfaces of the medial 1/3 of the hand?
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Superficial branch of Ulnar N
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Which portion of the brachial plexus may be severely injured as a result of a sudden, forcible widening of the angle between the shoulder and the head?
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Upper trunk
(avulsion of the C5-C6 roots) *Often seen in individuals thrown from a moving vehicle or horseback. |
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Which portion of the brachial plexus is most likely to be injured during delivery, where the infant's should becomes lodged against the mother's pelvis (shoulder dystocia)?
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Upper trunk
(avulsion of the C5-C6 roots) *Shoulder dystocia is considered an obstetrical emergency |
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Which portion of the brachial plexus is most likely to be injured by an excessively increased angle between the body trunk and upper limb?
(Ex: person using an outstretched arm to grasp a tree branch in breaking a fall) |
Lower brachial plexus
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Nerve injury that results from tearing away the nerve root at the spinal nerve.
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Avulsion
(most severe nerve injury) |
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Nerve injury that results from a tearing away the nerve at a site other than the root/spinal nerve attachment.
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Rupture
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Nerve injury that results from the formation of scar tissue, preventing appropriate nerve conduction.
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Neuroma
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Nerve injury that results from a stretched or damaged nerve that is not torn.
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Neuroapraxia
(least severe nerve injury) |
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What type of brachial plexus injury results in Erb-Duchenne palsy?
What are the clinical characteristics of this injury? |
Upper plexus injury
Caused by excessive separation of the head and shoulder, and affects the C5-C6 nerves and brachial plexus roots. (Paralysis--> supraspinatus, infraspinatus, rhomboids, deltoid, biceps, brachialis, and supinator muscles) *Results in characteristic "waiter's tip" position, with the arm adducted in internal rotation. |
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This injury results in weakness and atrophy affecting the intrinsic muscles of the hand, producing a characteristic claw-hand deformity.
What type of injury typically causes this? |
Lower plexus injury-- "Klumpke's paralysis"
*Caused by excessive traction on the upper limb--> damages Ulnar N (Avulsion of the T1 cervical nerve can also produce a concomitant Horner syndrome) |
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What type of injury results in a characteristic "winged scapula" and an inability to elevate the arm above the head?
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Damage to long thoracic N
Can be caused by penetrating chest wounds, damage during chest wall or thoracic surgery, and contact sports injuries. |
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Damage to which nerve is characterized by:
1. Atrophy of the supraspinatus and infraspinatus muscles 2. Difficulty initiating arm abduction 3. External rotation of the arm |
Suprascapular nerve damage
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Deficits in the lateral rotation and arm abduction may indicate damage to which nerve?
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Axillary nerve
(weakness in Deltoid and Teres minor muscles) |
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Which nerve is most likely damaged if the following signs are presented:
1. Weakened flexion of the supinated forearm 2. Weakness or paralysis and/or atrophy of anterior arm muscles 3. Sensory deficits in the lateral portion of the forearm. |
Musculocutaneous N
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The supinator muscle is innervated by which nerve?
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Radial N
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The abductor pollicis longus muscle is innervated by which nerve?
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Radial N
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Injury to which nerve produces a characteristic "wrist drop" due to wrist extensor weakness?
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Radial N
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Injury to which nerve will result in an inability to pronate the forearm and flex the interphalangeal joints, and weakness of thumb opposition and abduction?
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Median N
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A "hand of benediction" is a clinical sign which indicates damage to which nerve?
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Median N
(when patient makes a fist, 2nd and 3rd fingers are partially extended) |
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What syndrome is caused by entrapment of the median N between the heads of the pronator teres muscle?
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Pronator syndrome
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What syndrome results in pain and tenderness along the proximal aspect of the naterior forearm and sensory loss over the palm and thenar eminence?
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Pronator syndrome
(Median N entrapped b/w heads of pronator teres) |
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Damage to which nerve can result in claw-hand deformity and paralysis/atrophy of intrinsic hand muscles?
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Ulnar N
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A patient presents with upper limb neurologic deficits, Horner's syndrome, and subscapular paint. This patient has a history of smoking.
What is the probable diagnosis? |
Pancoast's tumor
(cancer in the apex of the lung) |
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Syndrome caused by trauma to the cervical/shoulder region that can produce a transient brachial brachial plexus injury--also known as a "stinger."
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Burner's syndrome
(often seen in young athletes playing contact sports) *Caused by overstretching or micro-tears of brachial plexus roots |