Gross Veterinary Anatomy Notes

Composition of Bones

• Organic framework (1/3): fibrous tissue and cells, including collagen and GAG.

• Inorganic framework (2/3): Calcium and phosphorus salts, primarily CaPO4$(hydroxyapatitecrystals),also$ CaCO3$and$ MgPO_4.

Bone Ossification

• Formation of bones via calcium salt deposition on osteoid matrix.

  • Intramembranous: membrane to bone.

  • Endochondral: cartilage to bone.

Bone Mineralization and Demineralization

• Deposition and withdrawal of calcium salts.

• Influenced by calcitonin (thyroid) and parathormone (parathyroids).

Skull/Cranium

• Divided into facial/palatal and neural/braincase regions.

Bones of the Braincase (Paired)

• Exoccipital, Frontal, Parietal, Temporal

Bones of the Braincase (Unpaired)

• Supraoccipital, Basioccipital, Basisphenoid, Presphenoid, Ethmoid, Interparietal

Bones of the Face and Palate (Paired)

• Premaxillae/Incisive, Maxilla, Nasal, Dorsal nasal concha, Ventral nasal concha, Zygomatic, Palatine, Lacrimal, Pterygoid, Mandible

Bones of the Face and Palate (Unpaired)

• Vomer

Bones of Hyoid Apparatus and Middle Ear (Paired)

• Stylohyoid, Epihyoid, Ceratohyoid, Thyrohyoid, Malleus/Hammer, Incus/Anvil, Stapes/Stirrup (Columella)

Bones of Hyoid Apparatus and Middle Ear (Unpaired)

• Basihyoid

Craniometric Points

• Inion: central surface point of external occipital protuberance.

• Bregma: junction of right and left fronto-parietal suture.

• Nasion: junction of R & L nasofrontal suture.

• Prosthion: rostral end of interincisive suture.

• Pogonion: most rostral part of mandible.

• Basion: middle of ventral margin of foramen magnum.

Related Measurements

• Facial length: nasion to prosthion.

• Facial width: widest interzygomatic distance.

• Cranial length: inion to nasion.

• Cranial width: widest interparietal distance.

• Cranial height: middle of external acoustic meatus to bregma.

• Mandibular length: caudal border of condyle to pogonion.

• Skull length: inion to prosthion.

• Skull width: widest interzygomatic distance.

• Skull base length: basion to prosthion.

Vertebral Column/Spine

• 50 irregular bones for protection.

Anatomical Segments of Vertebrae

• Cervical (neck).

• Thoracic (back).

• Lumbar (loin).

• Sacral (croup).

• Caudal/Coccygeal (tail).

Parts Common to All Vertebrae

• Body (and head): nucleus pulposus and annulus fibrosus.

• Vertebral arch (and notch): pedicles (wall); laminae (roof).

Processes

• Spinous: all, except atlas and 7th caudal vertebrae and beyond.

• Transverse: all vertebrae.

• Cranial and caudal articular: all vertebrae.

• Mammillary: extension of cranial articular process (from 11th thoracic to 7th lumbar; then from 2nd to 10th thoracic - in transverse process).

• Accessory: from mid-thoracic to 6th lumbar.

Ribs (Costae)

• Forms lateral aspect of thoracic skeleton.

Parts of Rib

• Head, neck, tubercle, angle of rib, shaft, costal groove, distal extremity.

  • Sternal (1st to 9th): directly attached to sternum.

  • Asternal (10th to 12th): attached to each other forming “costal arch”.

  • Floating (13th): not attached to sternum or costal arch.

Sternum

• Unpaired segmental series of 8 bones forming the floor of thorax.

  • Manubrium sterni.

  • Unpaired sternebrae segments (dorso-ventrally flattened).

  • Xiphoid process.

Indices

• Facial index: $\frac{facial width * 100}{facial length}$

• Cranial index: $\frac{cranial width * 100}{cranial length}$

• Skull index: $\frac{skull width * 100}{skull length}$

Types of Skull

• Dolichocephalic: long, narrow-headed.

• Mesaticephalic: medium proportion.

• Brachycephalic: short, wide-headed.

Sinuses

• Cavities in skull communicating with nostril and containing air.

Paranasal Sinuses

• MEFS: Maxillary, Ethmoidal, Frontal, Sphenoidal.

Cavity

• A hollow or potential space within the body or its organs.

Structures that enter in the formation of a body cavity

1. roof (dorsal wall)

2. wall (lateral boundaries)

3. floor (ventral wall)