EAR
Organ of hearing and equilibrium. Also known as, Teloreceptor or
phonoreceptor or Stato-acoustic receptor.
It has three divisions: external ear ,middle ear, internal ear.
External Ear
External ear is formed by two parts :auricle or pinna and external auditory
meatus.
Auricle or pinna
Auricle or pinna of external ear consist of fibro cartilaginous plate covered by
connective tissue and skin. In man, extrinsic and intrinsic muscles of auricle
are rudimentary and the movements is not possible. The depression of auricle
, which forms the orifice of external auditory meatus is called concha.
External auditory meatus tarts from concha and extends inside as a slightly
covered canal, with length of about 55mm
External auditory meatus
Cartilaginous part is the initial part of external auditory meatus and is made
up of cartilage . It is covered by thick skin, which contains stiffs hairs. These
hairs prevent the entry of foreign particles . Large sebaceous glands and
ceruminous glands are also present in the skin covering this portion.
Secretions of ceruminous glands, sebaceous glands and desquamated
epithelial cells from the earwax.
Inner part of external auditory meatus is also covered by skin. Only
sebaceous glands are present here. Skin covering this portion is continuous
with particular layer of tympani membrane.
Middle ear
Middle ear or tympanic cavity is a small narrow irregular laterally compressed
chamber, situated within the temporal bone. It is also known as tympanum. It
is separated from external unitary meatus by tympanic membrane. Middle
ear consist of the following structure: Auditory ossicles, auditory muscles and
Eustachian tube.
Tympanic membrane is a thin, semi-transparent membrane, which separates
the middle ear from external auditory meatus.
Organ of hearing and equilibrium. Also known as, Teloreceptor or
phonoreceptor or Stato-acoustic receptor.
It has three divisions: external ear ,middle ear, internal ear.
External Ear
External ear is formed by two parts :auricle or pinna and external auditory
meatus.
Auricle or pinna
Auricle or pinna of external ear consist of fibro cartilaginous plate covered by
connective tissue and skin. In man, extrinsic and intrinsic muscles of auricle
are rudimentary and the movements is not possible. The depression of auricle
, which forms the orifice of external auditory meatus is called concha.
External auditory meatus tarts from concha and extends inside as a slightly
covered canal, with length of about 55mm
External auditory meatus
Cartilaginous part is the initial part of external auditory meatus and is made
up of cartilage . It is covered by thick skin, which contains stiffs hairs. These
hairs prevent the entry of foreign particles . Large sebaceous glands and
ceruminous glands are also present in the skin covering this portion.
Secretions of ceruminous glands, sebaceous glands and desquamated
epithelial cells from the earwax.
Inner part of external auditory meatus is also covered by skin. Only
sebaceous glands are present here. Skin covering this portion is continuous
with particular layer of tympani membrane.
Middle ear
Middle ear or tympanic cavity is a small narrow irregular laterally compressed
chamber, situated within the temporal bone. It is also known as tympanum. It
is separated from external unitary meatus by tympanic membrane. Middle
ear consist of the following structure: Auditory ossicles, auditory muscles and
Eustachian tube.
Tympanic membrane is a thin, semi-transparent membrane, which separates
the middle ear from external auditory meatus.
