Exam 1: Brachial Plexus
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Exam 1: Brachial Plexus
anatomy brachial plexus
review of lecture 6/8 on brachial plexus for exam 1
Where do the brachial plexus orginate?
from ventral primary rami of C5-T1
How many roots does the brachial plexus have?
The five roots combine to form how many trunks?
The three trunks split to form what kind of divisions?
anterior and posterior
The divisions combine to form how many cords?
Where are the cords of the brachial plexus found?
surrounding the axillary a.
The three cords give rise to how many terminal branches?
What are terminal branches?
nerves which supply motor and sensory innervation to the upper extremity
What are the names of the 3 trunks of the brachial plexus?
upper (superior) trunk
lower (inferior) trunk
The three trunks each split to form the:
How is the upper trunk formed?
by union of C5-6
How is the middle trunk formed?
continuation of C7
How is the lower trunk formed?
union of C8-T1
Name the three cords of the brachial plexus:
What spinal nerves are represented by the lateral cord?
How is the lateral cord formed?
union of anterior divisions of upper and middle trunks
What spinal nerves are represented by the medial cord?
How is the medial cord formed?
continuation of anteior division of lower trunk
What spinal nerves are represented by the posterior cord?
How is the posterior cord formed?
union of posterior divisions of all three trunks
What are the names of the terminal branches of the brachial plexus?
What are the branches of the lateral cord?
lateral pectoral n.
lateral root of median n.
What spinal nerves are represented by the lateral pectoal n.?
What spinal nerves are rpresented by the musculocutaneous n.?
What are the branches of hte medial cord?
medial pectoral n.
medial brachial cutaneous
medial antebrachial cutaneous
medial root of median n.
What spinal nerves are represented by the medial pectoral n.?
What spinal nerves are represented by the medial brachial cutaneous?
What spinal nerves are represented by the medial antebrachial cutaneous?
What spinal nerves are represented by the ulnar n?
What are the branches of the posterior cord?
lower subscapular n.
What spinal nerves are represented by the upper subscapular n?
What spinal nerves are represented by the thoracodorsal n.?
What spinal nerves are represented by the lower subscapular n.?
What spinal nerves are represented by the axillary n.?
What spinal nerves are represented by the radial n?
How is the median n. formed?
the two roots of the median nerve combine to form the median nerve
What part of the brachial plexus is affected by Erb's Palsy (Erb-Duchenne paralysis)?
upper part of plexus, C5-6
What causes Erb's Palsy?
excessive separation of neck and shoulder
severe stretching of an infant's neck during delivery
What happens to the nerves with Erb's Palsy?
dorsal and ventral nerve roots are pulled out of spinal cord from C5-6
What muscles would be paralyzed with Erb's Palsy?
deltoid, supraspinatus, infraspinatus, teres minor and subscapularis
-flexors of elbow are weak
What are the symptoms of Erb's Palsy?
adduction and medial rotation of arm, extension of elbow, flexion of hand, loss of sensation in C5-6 dermatomes supplied by dorsal and ventral primary rami
-skin of back and lateral surface of upper extremity
What part of the brachial plexus is affected by Klumpke's (Klumpke-Dejerine paralysis)?
lower part of plexus, C8-T1
What part of the body is affected by Klumpke's?
distal part of upper extremity (forearm and hand)
What is the cause of Klumpke's?
upper extremity suddenly pulled upward
grasp something to break a fall
What is affected by Klumpke's?
muscles and skin innervated by the ulnar nerve
What impairments would occur with Klumpke's?
wrist flexion and movements of may of the intrinsic muscles of the hand
reduced sensation along medial side of arm,forearm, and hand
What happens if Klumpke's occurs at birth?
affected upper extremity will not grow to same size or length of the unaffected extremity
When you think Klumpke's, think....
damaged ulnar N
What is the thoracic outlet?
space located between first 2 pairs of ribs
What is another name for thoracic outlet syndrome?
cervical rib syndrome
What is thoracic outlet syndrome?
chronic injury to brachial plexus in lower part of neck, often also involving injury to subclavian artery
What part of the brachial plexus is affected by thoracic outlet syndrome?
lower trunk at, or close to level where it crosses the first rib
What are the symptoms of thoracic outlet syndrome?
pain in fingers, hand, forearm, arm and shoulder, along with paresthesia perceived in the dermatomes of C8-T1
When you think thoracic outlet syndrome, think:
compressed inferior trunk, --ulnar N
transverse process of C7 grows and wraps around, kinda like a rib. Lies next to apex of axilla