Corpus3D

Spine

Mastoid process

Processus mastoideus

How to find it
Directly behind and below the earlobe you feel a firm rounded bony prominence. Have the head turn to the other side: sternocleidomastoid tightens and visibly runs towards it.
What you use it for
Attachment of sternocleidomastoid, splenius capitis and longissimus capitis. The fixed starting point for palpating the neck muscles.
On the bone
Temporal bone
Body region
Spine