External Ear and Auditory Canal Flashcards

Flashcards covering external ear anatomy (auricle/pinna, EAC), its subdivisions, landmarks, directional terms, and key relations from HEAR 1013 notes.

What are the two main parts that compose the external ear?

The auricle (pinna) and the external auditory canal (EAC or meatus).

What is the auricle (pinna)?

The visible part of the ear outside the head, composed mainly of elastic cartilage covered by skin; the lobule (earlobe) is not supported by cartilage.

What is the external auditory canal (EAC)?

A passage between the auricle and the tympanic membrane, with cartilaginous and bony portions.

Name the three major parts of the ear.

External (outer) ear, middle ear, and inner ear.

What are the three auditory ossicles?

Malleus (hammer), Incus (anvil), Stapes (stirrup).

What is the tympanic membrane called?

The eardrum.

What is the Eustachian tube?

The auditory tube connecting the middle ear to the nasopharynx.

What are the components of the inner ear?

Cochlea, vestibule, and semicircular canals.

Which parts of the ear are involved in hearing and which are involved in balance?

External and middle ears are involved in hearing; inner ear is involved in hearing and balance.

What are the two portions of the External Auditory Canal (EAC)?

Cartilaginous portion (outer 1/3) and bony portion (inner 2/3).

Describe the cartilaginous portion of the EAC.

The outer third; skin is thick with numerous sebaceous and ceruminous glands and hairs.

Describe the bony portion of the EAC.

The inner two-thirds; skin is thin, lacks hairs and glands, and is tender.

What is the approximate length of the EAC in adult males and females?

Males about 25 mm; females about 23 mm.

What is the shape of the External Auditory Canal?

An S-shaped curve.

What is the osseocartilaginous junction?

The junction where the cartilaginous portion meets the bony portion of the EAC.

What are the main parts of the auricle/lobule?

Helix; Crus of Helix; Cymba Conchae; Cavum Conchae; Antihelix; Crura of Antihelix; Triangular Fossa; Scaphoid Fossa; Tragus; Antitragus; Intertragal Notch; Lobule.

What is the helix?

The outer rim (border) of the pinna; an elevation. The term derives from Greek meaning 'to roll'.

What is the crus of the helix?

The part that partially divides the concha into a superior and an inferior part.

What is the concha and its subdivisions?

The concha is the deepest depression in the pinna; upper part is cymba conchae and lower part is cavum conchae.

What is the antihelix?

An elevation inside the pinna that divides into the crura of the antihelix.

What are the crura of the antihelix?

The crura are the limbs (arms) of the antihelix.

What is the triangular fossa?

A depression located between the crura of the antihelix.

What is the scaphoid fossa?

A depression located between the helix and the antihelix.

What is the tragus?

A small triangular elevation that partially occludes the external auditory canal.

What is the antitragus?

A small elevation opposite the tragus, separated by the intertragal notch.

What is the intertragal notch?

The notch that separates the tragus from the antitragus.

What is the lobule (earlobe)?

The bottom-most portion of the auricle; composed of adipose and tough areolar tissue, lacking the elasticity of the rest of the auricle.

What is the difference between a free and attached earlobe?

A free earlobe hangs freely; an attached earlobe is connected to the side of the head.

Which glands are present in the cartilaginous portion of the EAC?

Numerous sebaceous and ceruminous glands.

What is the meaning of the term 'helix' and what does 'crus' mean?

Helix derives from Greek meaning 'to roll/wrap'; Crus derives from Latin meaning 'leg'.

What is the hairy tragus?

Coarse hairs on the tragus that may appear with age in some men (a secondary sexual characteristic).

What is the hairy pinna?

Coarse hairs on the lower portions of the helix; a Y chromosome-linked trait seen in some men.

What is the standard anatomical position?

Standing erect with head facing forward; arms at sides with palms facing forward; feet parallel and slightly separated.

What is the first direction of the EAC's curve?

Inward, upward, and forward.