It's lined with mucous and helps regulate pressure around the eardrum so that sound waves can be transferred. Ears can vary, so what's considered normal anatomy of the inner or outer ear in one person ...

The labrum also serves as the attachment of a major tendon in the shoulder, the biceps tendon. Miniato MA, Anand P, Varacallo M. Anatomy, shoulder and upper limb, shoulder. In: StatPearls [Internet].