The auricle or auricula is the visible part of the ear that is outside the head. It is also called the pinna (Latin for "wing" or "fin", plural pinnae), a term that is used more in zoology. Structure The diagram shows the shape and location of most of these components: antihelix forms a 'Y' shape where the upper parts are: Superior crus (to the left of the fossa triangularis in the diagram) Inferior crus (to the right of the fossa triangularis in the diagram) Antitragus is below the tragus Aperture is the entrance to the ear canal Auricular sulcus is the depression behind the ear next to the head Concha is the hollow next to the ear canal Conchal angle is the angle that the back of the concha makes with the side of the head Crus of the helix is just above the tragus Cymba conchae is the narrowest end of the concha External auditory meatus is the ear canal Fossa triangularis is the depression in the fork of the antihelix Helix is the folded over outside edge of the ear Incisura anterior auris, or intertragic incisure, or intertragal notch, is the space between the tragus and antitragus Lobe (lobule) Scapha, the depression or groove between the helix and the anthelix Tragus Development The developing auricle is first noticeable around the sixth week of gestation in the human fetus, developing from the auricular hillocks, which are derived from the first and second pharyngeal arches. These hillocks develop into the folds of the auricle and gradually shift upwards and backwards to their final position on the head. En route accessory auricles (also known as preauricular tags) may be left behind. The first three hillocks are derived from the 1st branchial arch and form the tragus, crus of the helix, and helix, respectively. Cutaneous sensation to these areas is via the trigeminal nerve, the attendant nerve of the 1st branchial arch. The final three hillocks are derived from the second branchial arch and form the antihelix, antitragus, and lobule, respectively. These portions of the ear are supplied by the cervical plexus and a small portion by the facial nerve. This explains why vesicles are classically seen on the auricle in herpes infections of the facial nerve (Ramsay Hunt syndrome type II). The auricle's functions are to collect sound and transform it into directional and other information. The auricle collects sound and,