Changes

The vascular supply to the outer ear is provided by the '''great auricular arteries''' (ex internal carotid artery).  Venous drainage is via satellite veins to the '''internal maxillary veins'''.  Innervation is provided by the '''auriculopalpebral branches of cranial nerve VII''' to the auricular muscles and sensory supply by cervical nerve II and cranial nerve V.

The vascular supply to the outer ear is provided by the '''great auricular arteries''' (ex internal carotid artery).  Venous drainage is via satellite veins to the '''internal maxillary veins'''.  Innervation is provided by the '''auriculopalpebral branches of cranial nerve VII''' to the auricular muscles and sensory supply by cervical nerve II and cranial nerve V.

In the tissues medial to the ear canal lie the auricular and superficial temporal arteries.  Laterally is the '''parotid salivary gland''' and also a branch of the [[Nervous System - CNS - Anatomy & Physiology#Innervation - Cranial Nerves|facial nerve]], external maxillary vein and branches of the external carotid artery.  The facial nerve exits the skull through the stylomastoid foramen behind the osseous bulla; it passes below the rostroventral aspect of the horizontal ear canal.  The '''auriculo-temporal''' branch of the mandibular portion of the [[Nervous System - CNS - Anatomy & Physiology#Innervation - Cranial Nerves|trigeminal nerve]] (CN V) and branches of the facial nerve pass rostral to the vertical ear canal.

In the tissues medial to the ear canal lie the auricular and superficial temporal arteries.  Laterally is the '''parotid salivary gland''' and also a branch of the [[Cranial Nerves - Anatomy & Physiology|facial nerve]], external maxillary vein and branches of the external carotid artery.  The facial nerve exits the skull through the stylomastoid foramen behind the osseous bulla; it passes below the rostroventral aspect of the horizontal ear canal.  The '''auriculo-temporal''' branch of the mandibular portion of the [[Cranial Nerves - Anatomy & Physiology|trigeminal nerve]] (CN V) and branches of the facial nerve pass rostral to the vertical ear canal.

The cartilage and bony process of the external ear and the tympanic membrane are covered by skin.  The skin of the normal ear has a thin stratified keratinising epidermis and a thin dermis containing adnexal structures – [[Hair - Anatomy & Physiology|hair follicles]], [[Skin - Anatomy & Physiology#Glands|sebaceous and apocrine glands]].  The density of hair follicles on the concave pinna is variable, as is the density and distribution of hair follicles in the ear canal itself.  Some species are devoid of hair in the lower (proximal) ear canal (eg horse); hair follicle density in the dog is variable – usually simple but in some breeds compound hair follicles.

The cartilage and bony process of the external ear and the tympanic membrane are covered by skin.  The skin of the normal ear has a thin stratified keratinising epidermis and a thin dermis containing adnexal structures – [[Hair - Anatomy & Physiology|hair follicles]], [[Skin - Anatomy & Physiology#Glands|sebaceous and apocrine glands]].  The density of hair follicles on the concave pinna is variable, as is the density and distribution of hair follicles in the ear canal itself.  Some species are devoid of hair in the lower (proximal) ear canal (eg horse); hair follicle density in the dog is variable – usually simple but in some breeds compound hair follicles.