Intro-Ribs & Sternum

• Comparative Anatomy is the description and comparison of structure of animals, and forms the basis for their classification
• The lungs are cranial to the intestines
• The intestines are caudal to the lungs
• The cerebrum is rostral to the cerebellum
• The kidneys are dorsal to the intestines
• The intestines are ventral to the kidneys
• The heart is medial to the lungs
• The ribs are lateral to the lungs
• The hoof is distal to the knee
• The femur is deep to the quadriceps muscles
• Prone refers to a position in which the dorsal aspect of the body or any extremity is uppermost
• Supine refers to a position in which the ventral aspect of the body or palmar or plantar aspect of any extremity is uppermost
• The general plan of construction is based on morphological principles: Zygomorphism, Metamerism, Tubulation, Stratification
• Each animal can be divided into right and left halves or ANTIMERES
• Principle of Zygomorphism: Paired or homotypical organs, unpaired organs, functional asymmetry
• Ovulation in bovine occurs more frequently in the right ovary; in chicken in the left ovary and oviduct
• Serial homology is the craniocaudal succession of similar homologous segments
• Metamerism is a system of structures in which similar segments succeed each other craniocaudally. It is best seen in embryos and becomes less evident in adults
• Principle of Tubulation determines the presence of a dorsal tube (neural tube) and ventral tube (gut) in the body of vertebrates
• Layers of the skin

  Epidermis: stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, stratum basale

  Dermis

  Subcutis
• Bones covered by:

  Periosteum: substantia compacta, substantia spongiosa, cavum medullare (medullary cavity)

  Vessels: tunica externa, tunica media, tunica mucosa

  Other viscera: tunica mucosa, tunica submucosa, tunica muscularis, tunica serosa
• Homology referees to identical structures having the same origin and location in different animals
• Analogy indicates only identity of function
• Normal in medicine means healthy; in anatomy it presents different connotations
• Teats of animals:

  Horse 1 pair, cow 2 pairs, dog 5 pairs, sow 8-10 pairs
• Variations is the slight deviations of the normal morphologic pattern of an organ
• 2 kinds of variations (Guyenot, 1950)

  Somatic/Somations - appear in the body or soma of the animal and are not hereditary

  Germinal or Mutations - occur in the germ cells and are hereditary
• Variant is the deviated organ
• The deviation can be:

  1. An increase in the number of parts
  2. Reduction of parts
  3. Modification of form
• Rudimentary - imperfectly developed; vestigial. A rudimentary organ may sometimes reach full development and become atrophied
• Atrophy means a decrease in size of a normally developed organ or tissue
• Variations can be found in deviations of:

  1. Holotopy - the relation between the organ and the body as a whole, e.g heart-left side (right side, ectopic cordis)
  2. Syntopy - the relation of the structure and its immediately adjacent organs e.g kidneys are bean-shaped or lobulated
  3. Idiotopy - the relation of the parts of an organ among themselves, e.g digits/metatarsals
  4. Histotopy - the relation of the layers, coats or tissues if an organ among themselves, e.g hyperkeratinization
• Anomaly is a severe deviation for the normal pattern accompanied by alteration or impairment of function, e.g harelip, cleft palate, cervical rib in man
• Monster/monstrosity is a severe anomaly, incompatible with life
• Teratology is the study of the causes and effects of congenital malformations and developmental abnormalities
• General factors of Variations:

  1. Age
  2. Sex
  3. Race
  4. Biotype
  5. Evolution
  6. Environment
• The thymus grows until sexual maturity, and them becomes atrophied organ in a relatively short period
• Abrasion is the modification of shape of the incisor crown in the equine, bovine, and carnivore
• Presence of large numbers of horn rings in old bovine
• White hair on the head of aged equine