The superficial temporal artery divides above the zygomatic arch into a frontal branch (running obliquely toward the forehead, supplying the frontalis and forehead skin) and a parietal branch (running posterosuperiorly to supply the parietal and temporal scalp). Together these branches supply the majority of the scalp anterior to the ear and are the dominant pedicles for scalp and forehead flaps.
The superficial temporal artery frontal branch is used for extracranial-intracranial (EC-IC) bypass surgery in moyamoya disease and chronic ICA occlusion, anastomosed to the MCA cortical branch to augment cerebral blood flow. The parietal branch supplies the temporoparietal fascia flap (TPF flap), a thin vascularised fascial flap used for ear reconstruction, scalp coverage, and orbital floor repair. Both branches are at risk during temporal craniotomy skin incision, and the dominant branch should be preserved for potential bypass. Giant cell arteritis affects the superficial temporal artery, and temporal artery biopsy samples the frontal or parietal branch for histological diagnosis.
Temporal artery biopsy for suspected giant cell arteritis samples at least 2 cm of the frontal or parietal branch of the STA under local anaesthesia; skip lesions mean a negative biopsy does not exclude the diagnosis, and bilateral biopsy increases yield; the biopsy should be performed before corticosteroids are started if possible but steroids must not be delayed for biopsy.
