Brachial Plexus
Terms
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- What are the roots of the brachial plexus?
- Ventral rami of C5-T1
- What are the trunks of the brachial plexus?
- upper (C5-6), middle (C7), and lower (C8-T1)
- What are the direct branches off the superior trunk of the brachial plexus?
- suprascapular nerve (C4-5), nerve to subclavius
- What nerve branch comes off the anterior division of the upper trunk of the brachial plexus?
- lateral pectoral nerve
- What does the anterior division of the superior trunk of the brachial plexus merge into?
- the lateral cord
- What does the posterior division of the superior trunk of the brachial plexus merge into?
- the posterior cord
- What do the divisions of the middle trunk of the brachial plexus merge into?
- anterior division merges into the lateral cord, posterior division into the posterior cord
- What trunk and division of the brachial plexus gives rise to the medial pectoral nerve?
- anterior division of inferior trunk
- What does the lateral cord become?
- musculocutaneous nerve, also provides sensory axons to the median nerve
- What does the posterior cord of the brachial plexus become?
- axillary and radial nerves (upper subscapular, thoracodorsal, lower subscapular)
- What nerve supplies the arm flexors?
- musculocutaneous (C5-6)
- What branches make up the median nerve?
- C5-T1
- What nerve supplies the flexor digitorum profundus of index and middle fingers, flexor pollicis longus and pronator quadratus?
- anterior interosseous nerve
- What nerve supplies forearm/wrist flexors and pronators as well as LOAF muscles in Hand (lumbricals of index and middle fingers, opponens pollicui, abductor pollicis longus and flexor pollicus brevis)?
- Median nerve
- What nerve supplies the deltoid and teres minor muscles?
- axillary nerve (C5-6)
- What nerve supplies all of the extensors of the forearm and hand?
- radial nerve (C5-8)
- What nerve supplies the extensors of the wrist, thumb, and fingers?
- Posterior interosseus (C7-8)
- What nerve supplies all intrinsic hand muscles except LOAF (lumbricals of index finger, opponenes pollicis, abductor pollicis longus, flexor pollicis brevis) muscles?
- Ulnar nerve
- What palsy is caused by upper plexus injury due to head/shoulder distraction?
- Duchenne -Erb palsy
- What palsy is caused by lower brachial plexus injury, usually traction on an abducted arm?
- Klumpke's palsy
- What % of patients with obstetrical brachial plexus injuries recover spontaneously?
- 90%
- 1st rib fractures may cause injuries to what portion of the brachial plexus?
- lower trunk
- Midhumeral fractures are often associated with injury to what nerve?
- radial nerve
- What vessels are often associated with plexus injury
- axillary artery and vein
- What syndrome is associated with a cervical rib?
- thoracic outlet syndrome
- What is the Gilliatt-Sumner hand?
- wasting of the thenar and hypothenar muscle groups
- what syndrome is associated with the Gilliatt-Sumner hand?
- thoracic outlet syndrome
- What nerve tumors often have well-defined margins allowing total resection?
- Schwannomas
- What tumors are frequently associated with Von Recklinghausen's syndrome (NF-1)?
- neurofibromas
- What is Parsonage-Turner syndrome?
- idiopathic brachial neuritis
- What are the symptoms of idiopathic brachial neuritis?
- acute onset of intense shoulder pain followed by weakness in the shoulder musculature.
- What is Pancoast's syndrome
- brachial plexus neuropathy secondary to extrinsic compression from tumors
- Where is the lesion usually found in Pancoast's syndrome?
- C8-T1
- How does radiation cause brachial plexus neuropathy?
- fibrosis and edema of the brachial plexus
- What is Horner's syndrome?
- Eyelid ptosis, miosis and anhydrosis
- Horner's syndrome suggests a lesion at which part of the brachial plexus?
- Lower portion
- What is a waiter's tip deformity?
- shoulder internal rotation with elbow extension and wrist flexion
- What is a claw hand?
- extension at MCPs and flexion at interphalangeal joints
- What is Adson's test?
- Have patient hyperextend their neck and rotate their neck toward affected side while you gently tug downward on arms. A positive test is loss of radial pulse
- What does a positive Adson's test indicate?
- Vasculogenic thoracic outlet syndrome
- What nerve is associated with a winged scapula?
- long thoracic
- Where do the sensory roots of the median nerve arise from?
- C5-7
- Where do the motor roots of the median nerve arise from?
- C8-T1
- Nerve root avulsion is more common in what portion of the brachial plexus?
- lower plexus (nerve is bound down in connective tissue at C5-7
- What is the rate of peripheral nerve regeneration?
- 1 mm per day (about an inch per month)
- Which brachial plexus repairs have a better outcome - C5-6 or C8-T1?
- C5-6
- what two nerves come directly off of the roots?
- long thoracic (C5,6,7); dorsal scapular nerve (C5)
- what does the long thoracic nerve supply?
- serratus anterior
- what does the dorsal scapular nerve supply?
- and levator scapulae muscles
- what does the suprascapular nerve supply?
- sensory fibers to the shoulder joint and provides motor innervation to the supraspinatus and infraspinatus muscles
- where does the phrenic nerve lie in relation to the plexus?
- anterior
- where does the spinal accessory nerve (CN XI)lie in relation to the plexus?
- posterior
- what does the phrenic nerve supply?
- diaphram
- what does the accessory nerve supply?
- trapezius