Changes

==The Canine Paw==

==The Canine Paw==

Composed of four weight-bearing toes, each with a claw and footpad. In addition there is a metacarpal/metatarsal footpad.

The canine paw is composed of four weight-bearing toes, each with a claw and footpad. In addition there is a metacarpal/metatarsal footpad.

 

====Footpad====

====Footpad====

* The epidermis is thick, pigmented, keratinised and hairless. It is arranged into conical papillae. '''Sweat/merocrine glands''' open onto the surface.

The epidermis of the footpad is thick, pigmented, keratinised and hairless. It is arranged into conical papillae with '''sweat/merocrine glands''' opening onto the surface of the footpad. The dermis of the dense connective tissue is papillated. The subcutaneous tissue is mainly adipose tissue with reticular, collagenous and elastic fibres. These help form '''digital cushions''' deep to the foot pad. The '''digital pads''' are oval shaped and support the distal interphalangeal joints whilst the metacarpal/metatarsal pads are heart shaped, with the apex pointing distally and supporting the metacarpophalangeal joints. A small carpal pad is present medial and distal to the accessory carpal bone.

* The dermis of the dense connective tissue is papillated.

* The subcutaneous tissue is mainly adipose tissue with reticular, collagenous and elastic fibres. These help form '''digital cushions''' deep to the foot pad.

* The '''digital pads''' are oval shaped and support the distal interphalangeal joints. The metacarpal/metatarsal pads are heart shaped, with the apex pointing distally and support the metacarpophalangeal joints.

* A small carpal pad is present medial and distal to the accessory carpal bone.

 

====Claw====

====Claw====

 

The claw is the horny covering of the distal phalanx. The walls of the claw, which are continuous dorsally, embrace the soft flaky horn of the sole when they touch the ground. The proximal part of the claw, called the '''coronary border''' fits between the ungual groove and the ungual crest, where it is continuous with the skin, making the '''claw fold'''. The periosteum of the distal phalanx is continuous with the dermis, which is arranged in '''papillae'''. Papillae cover the dorsal aspect of the phalanx and contain the '''germinative layer''' which is the flat keratinised epidermal cells which are considered responsible for horn formation. The lateral and medial walls are formed by dermal laminae, rather than the papillae. The plantar aspect of the claw is produced by papillae but this horn is very friable. Canine claws grow at rapid rate and so if they aren't worn by active wear they must be trimmed. Care must be taken as the dermis is highly vascular and bleeding will occur if it is cut into.  

* This is the horny covering of the distal phalanx. The walls of the claw, which are continuous dorsally, embrace the soft flaky horn of the sole when they touch the ground.

* The proximal part of the claw, '''coronary border''' fits between the ungual groove and the ungual crest, where it is continuous with the skin, making the '''claw fold'''.  

* The periosteum of the distal phalanx is continuous with the dermis, which is arranged in '''papillae'''. These cover the dorsal aspect of the phalanx and contain the '''germinative layer'''. These are flat keratinised epidermal cells which are considered responsible for horn formation.  

* The lateral and medial walls are formed by dermal laminae, instead of papillae.

* The plantar aspect of the claw is produced by papillae but this horn is very friable.

* The claws grow at rapid rate and so if they aren't worn by active wear they must be trimmed. Care must be taken as the dermis is highly vascular and bleeding will occur if cut into. To ensure that only the epidermis is cut take great care.

[[Category:Musculoskeletal System - Anatomy & Physiology]]

[[Category:Musculoskeletal System - Anatomy & Physiology]]

[[Category:To Do - A&P]]

[[Category:To Do - A&P]]