Brachial Plexus
what two nerves come directly off brachial plexus nerve roots?
dorsal scapular nerve (C4, C5) and long thoracic nerve (C5, C6, C7)
the long thoracic nerve innervates which axillary muscles?
serratus anterior
the nerve to subclavius innervates which axillary muscles?
subclavian
the upper subscapular nerve innervates which axillary muscles?
subscapularis
which nerves originate directly from the superior trunk?
suprascapular (C5-C6) and nerve to subclavius (C5-C6)
the suprascapular nerve innervates which axillary muscles?
supraspinatus and infraspinatus
the anterior divisions of which trunks form the medial cord?
the inferior trunk
C5 innervates which cords?
the lateral and posterior cords
C6 innervates which cords?
the lateral and posterior cords
C7 innervates which cords?
the lateral and posterior cords
the middle trunk splits into two divisions; into which cords do these divisions incorporate?
the lateral and posterior cords
the superior trunk splits into two divisions; into which cords do these divisions incorporate?
the lateral and posterior cords
which nerves originate directly from the lateral cord?
the lateral pectoral nerve (C5-C7)
C7 innervates which cords?
the lateral, posterior, and medial cords (all)
C8 innervates which cords?
the medial and posterior cords
T1 innervates which cords?
the medial and posterior cords
the inferior trunk splits into two divisions; into which cords do these divisions incorporate?
the medial and posterior cords
C8 innervates which cords?
the posterior and medial cords
T1 innervates which cords?
the posterior and medial cords
the anterior divisions of which trunks form the lateral cord?
the superior and middle trunks
C5 innervates which trunks?
the superior trunk
what is the name of the trunk that is a combination of C5 and C6?
the superior trunk
the posterior divisions of which trunks form the posterior cord?
the superior, middle, and inferior trunks (all three)
which nerves originate directly from the posterior cord?
upper subscapular (C5-C6), thoracodorsal (C6-C8), and lower subscapular (C5-C6)
injury to radial nerve at the axillary region would cause?
weakness trying to push something away from arm, difficulty extending the wrist, fingers and opening the hand; "wrist drop" (can result from improper use of crutches)
the dorsal scapular nerve is innervated by which spinal cord rami?
C4 and C5
the axillary branch is innervated by which spinal rami?
C5 and C6
the long thoracic nerve is innervated by which spinal cord rami?
C5, C6, and C7
the musculocutaneous branch is innervated by which spinal rami?
C5, C6, and C7
the median branch is innervated by which spinal rami?
C5-C8, T1 (all)
the radial branch is innervated by which spinal rami?
C5-C8, T1 (all)
the ulnar branch is innervated by which spinal rami?
C7, C8, and T1
a lesion to the superior trunk would lead to what condition and what clinical presentation?
Erb's palsy; "waiter's tip" (includes abducted and medially rotated arm; pronation and extension at the elbow)
a lesion to the inferior trunk would lead to what condition and what clinical presentation?
Klumpke's palsy; "claw hand" (includes extremely extended wrist posture [wrist extensors are unopposed]; joints between hand and finger bones hyperextended, joints between finger segments flexed [intrinsic muscles of hand are unopposed])
the lower subscapular nerve innervates which axillary muscles?
Teres major and subscapularis
what nerves and muscles are affected by a lesion to the superior trunk?
affected nerves = axillary, suprascapular, musculocutaneous, and radial; affected muscles = deltoid, teres minor, supraspinatus, infraspinatus, elbow flexors, brachioradialis, and supinator
what nerves and muscles are affected by a lesion to the inferior trunk?
affected nerves = median and ulnar; affected muscles = ???
the posterior cord gives rise to which branches of the brachial plexus?
axillary and radial branches
injury to thoracodorsal nerve would cause?
innervation to latissimus dorsi; cannot raise trunk with upper limb (as in climbing)
injury to long thoracic nerve would cause?
innervation to serratus anterior; winging of scapula; cannot raise arms above 90 degrees
the thoracodorsal nerve innervates which axillary muscles?
latissimus dorsi
the dorsal scapular nerve innervates which axillary muscles?
levator scapulae, rhomboid minor, and rhomboid major
which nerves originate directly from the medial cord?
medial pectoral (C8, T1), medial brachial cutaneous (T1), and medial antebrachial cutaneous (C8, T1)
the medial cord gives rise to which branches of the brachial plexus?
median and ulnar branches
C8 gives rise to which branches of the brachial plexus?
median, radial, and ulnar branches
T1 gives rise to which branches of the brachial plexus?
median, radial, and ulnar branches
the inferior trunk gives rise to which branches of the brachial plexus?
median, radial, and ulnar branches
the lateral cord gives rise to which branches of the brachial plexus?
musculocutaneous and median branches
C5 gives rise to which branches of the brachial plexus?
musculocutaneous, axillary, median, and radial branches
C6 gives rise to which branches of the brachial plexus?
musculocutaneous, axillary, median, and radial branches
the superior trunk gives rise to which branches of the brachial plexus?
musculocutaneous, axillary, median, and radial branches
the middle trunk gives rise to which branches of the brachial plexus?
musculocutaneous, axillary, median, radial, and ulnar branches (all)
C7 gives rise to which branches of the brachial plexus?
musculocutaneous, median, radial, and ulnar branches
the lateral pectoral nerve innervates which axillary muscles?
pectoralis major
the medial pectoral nerve innervates which axillary muscles?
pectoralis major and pectoralis minor
