choicespolt.blogg.se - Auditory meatus

#Auditory meatus skin#
#Auditory meatus series#

On the cross-section, it is of oval shape. It has a sigmoid form and runs from behind and above downward and forward. The canal is approximately 2.5 centimetres (1 in) long and 0.7 centimetres (0.28 in) in diameter. Size and shape of the canal vary among individuals. The layer of epithelium encompassing the bony portion of the ear canal is much thinner and therefore, more sensitive in comparison to the cartilaginous portion. The bony part is much shorter in children and is only a ring ( annulus tympanicus) in the newborn. The bony part forms the inner two thirds. The cartilaginous portion of the ear canal contains small hairs and specialized sweat glands, called apocrine glands, which produce cerumen ( ear wax). The cartilage is the continuation of the cartilage framework of pinna.

The elastic cartilage part forms the outer third of the canal its anterior and lower wall are cartilaginous, whereas its superior and back wall are fibrous. The human ear canal is divided into two parts. The adult human ear canal extends from the pinna to the eardrum and is about 2.5 centimetres (1 in) in length and 0.7 centimetres (0.3 in) in diameter. The lymphatic drainage of the external ear is to the superficial parotid, mastoid, upper deep cervical and superficial cervical nodes.The ear canal ( external acoustic meatus, external auditory meatus, EAM) is a pathway running from the outer ear to the middle ear. Some individuals can complain of an involuntary cough when cleaning their ears - this is due to stimulation of the auricular branch of the vagus nerve (the vagus nerve is also responsible for the cough reflex).

Branches of the facial and vagus nerves - innervates the deeper aspect of the auricle and external auditory meatus.

#Auditory meatus skin#

Auriculotemporal nerve (branch of the mandibular nerve) - innervates the skin of the auricle and external auditory meatus.Lesser occipital nerve (branch of the cervical plexus) - innervates the skin of the auricle.Greater auricular nerve (branch of the cervical plexus) - innervates the skin of the auricle.

The sensory innervation to the skin of the auricle comes from numerous nerves: Venous drainage is via veins following the arteries listed above.

Maxillary artery (deep auricular branch) - supplies the deep aspect of the external acoustic meatus and tympanic membrane only.

The external ear is supplied by branches of the external carotid artery: The parts of the tympanic membrane moving away from the lateral process are called the anterior and posterior malleolar folds. The handle of malleus continues superiorly, and at its highest point, a small projection called the lateral process of the malleus can be seen. On the inner surface of the membrane, the handle of malleus attaches to the tympanic membrane, at a point called the umbo of tympanic membrane. The translucency of the tympanic membrane allows the structures within the middle ear to be observed during otoscopy. The membrane is connected to the surrounding temporal bone by a fibrocartilaginous ring. It is part of the outer ear, but the stages, symptoms. It is a connective tissue structure, covered with skin on the outside and a mucous membrane on the inside. The ear canal is the passage running from the outer ear to the middle ear. The tympanic membrane lies at the distal end of the external acoustic meatus.

It ends by running in an inferoanterior direction.

#Auditory meatus series#

This is where a series of movements of the auditory ossicles begins. On the opposite side of the tympanic membrane, the medial side, the malleus is attached with its handle.

In then turns slightly to move superoposteriorly. First, sound waves enter the external acoustic meatus, or ear canal, and vibrate the tympanic membrane that is located at the end of this canal.

It collects sound waves and channels them into the ear canal (external auditory meatus), where the.

Initially it travels in a superoanterior direction. The auricle (pinna) is the visible portion of the outer ear.

The external acoustic meatus does not have a straight path, and instead travels in an S-shaped curve as follows: The walls of the external 1/3 are formed by cartilage, whereas the inner 2/3 are formed by the temporal bone. The external acoustic meatus is a sigmoid shaped tube that extends from the deep part of the concha to the tympanic membrane.