Extra Upper Limb Nerves

Question 1

Paralysis of Serratus Anterior:

• Which nerve is involved?
• How can this be damaged?
• Consequences?
• Test?

Answer 1

• Long thoracic nerve (C5,6,7)
• Axillary node clearance
• Scapula moves laterally and posteriorly (away from thoracic wall). Can also mean that upper limb cannot be abducted above the horizontal level as the scapulas cannot rotate (to get the glenoid cavity to face superiorly).
• Test for winged scapula - get them to press against a wall.

Question 2

Injury of spinal accessory nerve (CNXI):

• Which muscle is affected?
• Which motion can be tested for weakness?

Answer 2

• Trapezius

- Shrugging movement

Question 3

Injury of thoracodorsal nerve:

• How can this be damaged?
• Which muscle is affected?
• Which motions are lost?

Answer 3

• Surgery (eg. axillary node clearance - as nerve passes along posterior border of the axilla).
• Latissimus Dorsi
• Extension + Adduction + Medial rotation of upper limb. Also reduced ability to pull trunk up during climbing.

Question 4

Injury to dorsal scapular nerve:

• Which muscles are affected?
• Which motion is lost?

Answer 4

• Rhomboids + Levator Scapulae

- Retraction of the scapulas

Question 5

Injury to Axillary nerve:

• Which muscles are affected?
• Common causes?
• Complications
• Which motions are lost?
• Any sensation loss?

Answer 5

• Deltoid + Teres minor
• Fractures to surgical neck of humerus + Dislocation of glenohumeral joint + Compression due to incorrect use of crutches + Injections.
• Causes denervation atrophy of the deltoid + teres minor.
• Loss/weakness of abduction (15-90 degrees) + flexion + extension + medial rotation + lateral rotation of upper limb.
• Sensation lost to regimental badge area.