Hematoma of the sternomastoid muscle detected in a 16 days old infant requires:
Sternomastoid tumour/Hematoma

Presents at about 7-10 days after birth
Situated at the junction of upper and middle third of the muscle
Etiology: rupture of sternocleidomastoid muscle fibres and blood vessels, due to:

– hematoma and cicatricial contracture
– Difficult breech delivery
– Attempted delivery after shoulder dystocia
– Excessive lateral flexion of neck following normal delivery.

Clinical features: Transient torticollis
Treatment:

– No treatment required, disappears spontaneously by 6 months of age
– Gentle movements and stretching of muscle done after feeds is useful
– Do not massage.
Immediate surgical evacuation
Surgical intervention within 2 weeks
Prophylactic antibiotic therapy
No immediate therapy