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Horn - Anatomy & Physiology (view source)
Revision as of 11:17, 5 August 2008
, 11:17, 5 August 2008→Structure and Function
==Structure and Function==
==Structure and Function==
Horns have a central, conical bony core or '''corunal process''' that grows out from the [[Skull and Facial Muscles - Anatomy & Physiology#Frontal Bone|frontal bone]] of the skull. The bone is hollow and the space within it is continuous with the [[Paranasal sinuses - Anatomy & Physiology|frontal sinuses]]. The surface of the bone is ridged and porous and is covered with papillated [[Skin - Anatomy & Physiology#dermis|dermis]] that is continuous with the periosteum and [[Skin - Anatomy & Physiology#epidermis|epidermis]] which keratinises and forms the protective covering of the horn.
In the neonate, the bone portion is very small, with a thin dermal and epidermal covering. Removal of this covering will prevent the horn from growing and thus remove the requirement for disbudding later in life.
If the skin covering the horn bud is not removed, the horn will continue to grow throughout the animal's life from the base, apically. Growth zones are visible with differing thickness of the keratin layer, relating to the nutritional status of the animal at that time.
The dermis of the horn is supplied by the '''corunal nerve''', which is a branch of the [[Nervous System - CNS - Anatomy & Physiology#Innervation - Cranial Nerves|maxillary nerve]] ('''CN V'''). This nerve is often blocked to provide local anaesthesia in the disbudding or de-horning process.
The primary function of horns is to convey social hierarchy. The larger the horns, the higher up the social group the animal is. They also have a thermoregulatory roll in cattle and goats. When the ambient temperature increases, the blood flow through the dermis of the horn also increases, thus facilitating heat loss through radiation from the horn surface.