Anatomy of histology
of hoof & integument Hoof structure:
Overview of integument system: Periople Waxy substance on outside of hoof.
Thick hoof Grows from a belt of epidermis at coronary
Integumentary system comprises of skin with its wall band (region where haired skin becomes
adnexal structures (hair and glands), horns/claws hoof)
(protection), hoofs, & other modifications of epithelial Deep side Intimately connected to underlying corium
covering of body. of hoof (which blends with periosteum of distal
Skin: important protection barrier which reduces: (1) wall phalanx).
water loss, (2) invasion by microorganisms, (3) Laminae Connection between hoof wall and corium;
abrasive trauma. interdigitating sheets of hoof wall & corium.
- Important organ of thermoregulation through 1. Insensitive laminae: part of epidermis
perspiration, control of cutaneous blood flow, and 2. Sensitive laminae: part of corium
disposition of hair coat. Sole Hard part of hoof in contact with ground;
All components are modifications of: extensive in horses, smaller in domestic
1. Surface epithelium (derived from embryonic ungulates.
ectoderm) Bulb Large part of palmar/plantar aspect of feet in
2. Underlying vascularized component (derived from ruminants & pigs. Bears most of animal’s
embryonic mesoderm) weight.
In fully developed skin, this becomes superficial
Digital Shock-absorbing modification of subcutis.
epidermis and deep dermis)
cushion (Deep relative to bulb).
- Hoofs & horns have homologous superficial epithelial
Note: Equine hoof has a V-shaped bulb, which is more
& deep connective tissue components (latter is called
flexible than adjacent sole, and bulb is harder than that of
corium: homologous to dermis).
other ungulates.
Modified epidermis:
Anatomy of hoof & claw:
Horse: hoof; pigs/ruminants:
claws
Derived from same skin.
Outer avascular epidermal
layer; Inner vascularized
dermis (corium).
, Lack well developed phalanges: hoof wall & small
bulb.
Don’t bear weight in ruminants.
- Pigs: 3 phalanges and smaller, well-developed hoof
Porcine declaws occasionally contact ground (sot
surfaces)
Digits in even-toed animals:
Digits III and IV (ruminants and pigs)
Axial: side of digit closest to midline of foot
Histology:
Abaxial: side of digit farthest from midline of foot
Hoof wall consists of nearly vertical axial portion that
reflect sharply caudad at toe (tip of hoof) to be
continuous with abaxial portion of wall.
- Abaxial hoof wall = convex and axial wall = concave;
both walls/surfaces are continuous with bulb of hoof.
Lateral digit bears more weight than medial one.
- Horse = sole and bulb of foot carry more weight than
walls and toe (pigs is the opposite)
- Bulb of porcine hoof provides larger proportion of
weight-bearing surface than in ruminants.
Declaws:
Accessory digits of ruminants: digit II (medial) and V Skin:
(lateral)
of hoof & integument Hoof structure:
Overview of integument system: Periople Waxy substance on outside of hoof.
Thick hoof Grows from a belt of epidermis at coronary
Integumentary system comprises of skin with its wall band (region where haired skin becomes
adnexal structures (hair and glands), horns/claws hoof)
(protection), hoofs, & other modifications of epithelial Deep side Intimately connected to underlying corium
covering of body. of hoof (which blends with periosteum of distal
Skin: important protection barrier which reduces: (1) wall phalanx).
water loss, (2) invasion by microorganisms, (3) Laminae Connection between hoof wall and corium;
abrasive trauma. interdigitating sheets of hoof wall & corium.
- Important organ of thermoregulation through 1. Insensitive laminae: part of epidermis
perspiration, control of cutaneous blood flow, and 2. Sensitive laminae: part of corium
disposition of hair coat. Sole Hard part of hoof in contact with ground;
All components are modifications of: extensive in horses, smaller in domestic
1. Surface epithelium (derived from embryonic ungulates.
ectoderm) Bulb Large part of palmar/plantar aspect of feet in
2. Underlying vascularized component (derived from ruminants & pigs. Bears most of animal’s
embryonic mesoderm) weight.
In fully developed skin, this becomes superficial
Digital Shock-absorbing modification of subcutis.
epidermis and deep dermis)
cushion (Deep relative to bulb).
- Hoofs & horns have homologous superficial epithelial
Note: Equine hoof has a V-shaped bulb, which is more
& deep connective tissue components (latter is called
flexible than adjacent sole, and bulb is harder than that of
corium: homologous to dermis).
other ungulates.
Modified epidermis:
Anatomy of hoof & claw:
Horse: hoof; pigs/ruminants:
claws
Derived from same skin.
Outer avascular epidermal
layer; Inner vascularized
dermis (corium).
, Lack well developed phalanges: hoof wall & small
bulb.
Don’t bear weight in ruminants.
- Pigs: 3 phalanges and smaller, well-developed hoof
Porcine declaws occasionally contact ground (sot
surfaces)
Digits in even-toed animals:
Digits III and IV (ruminants and pigs)
Axial: side of digit closest to midline of foot
Histology:
Abaxial: side of digit farthest from midline of foot
Hoof wall consists of nearly vertical axial portion that
reflect sharply caudad at toe (tip of hoof) to be
continuous with abaxial portion of wall.
- Abaxial hoof wall = convex and axial wall = concave;
both walls/surfaces are continuous with bulb of hoof.
Lateral digit bears more weight than medial one.
- Horse = sole and bulb of foot carry more weight than
walls and toe (pigs is the opposite)
- Bulb of porcine hoof provides larger proportion of
weight-bearing surface than in ruminants.
Declaws:
Accessory digits of ruminants: digit II (medial) and V Skin:
(lateral)
