A young mother brings in her 2 year-old boy because he has not moved his left arm since this morning. The boy was fine this morning until he was on the monkey bars and slipped, grabbing the bar as he fell. His mother noted a popping sound, but there was no other trauma and he didn't seem to be in any pain.

No previous medical problems

no medicines or allergies

Appearance:	VS Temp 98.8F, HR 122, RR 26. He is mildly irritable.
HEENT:	NC/AT, neck supple and nontender
Lungs:	clear bilaterally, no signs of trauma
Heart:	regular rate, no murmur
Abdomen:	soft, benign, no bruising
Extremities:	left arm limp at his side, the hand is mildly swollen with good pulses and fulll motor and sensory function in the hand. The other extremities are normal
Neuro:	Awake and cooperative