Common Bone Features: Holes and Depressed Areas

• _________ _________ : A hole in bone.

– Usually allow the passage of nerve or blood vessel or may exist simply to lighten structure (pelvis) • ______________ : A depressed or sunken area on the surface of a bone.

– Usually occupied by muscles or tendons.

The Skeleton

• ______________ Skeleton = Bones of head and trunk – skull, hyoid bone, vertebrae, ribs, sternum • _______________ Skeleton = Bones of limbs and appendages – thoracic and pelvic limbs • ______________ Skeleton = bones formed in the soft organs.

Skull

• Consists of 37 or 38 separate bones joined by immovable fibrous joints called ____________.

– exception: the ______________ is freely movable at is connected to the rest of the skull by a synovial joint.

• Skull bones are divided into 3 regions: – Bones of the ____________ – Bones of the ____________ – Bones of the ____________ • Within each region, there are external (visible) and internal (hidden within the skull) bones

Bones of the Cranium

• Cranium -portion of skull that surrounds the brain.

• External Bones of Cranium: – Frontal Bones (2) – – – – Interparietal Bones (2) Occipital Bone (1) Parietal Bones (2) Temporal Bones (2) • Internal Bones of Cranium: – Ethmoid Bone (1) – Sphenoid Bone (1)

• Single bone that forms the caudoventral portion or _________ of skull, most caudal skull bone.

Occipital Bone

• Importance: – Is where spinal cord exits skull • _______________ magnum – Skull bone that articulates with first cervical vertebrae (atlas).

• _____________ condyles atlantooccipital joint are articular surfaces on either side of foramen magnum that come together with the atlas to form the

Interparietal Bones

• Bone(s) located on dorsal __________ between occipital and parietal bones • Clearly visible in young animals, may fuse together in older animals.

• •

Parietal Bones

Two bones that form the dorsolateral walls of the cranium Well developed in dogs, cats and humans, but relatively small in horses and cattle.

• • Two bones located ventral to the parietal bones Importance: – – – Form walls of the cranium Contain middle and inner ear structures Form the temporomandibular joints with the ___________ (Lower jaw)

Temporal Bones

• • • •

Frontal Bones

Forms ______________ region of skull and a portion of the eye’s orbit.

Located rostral to parietal bone.

Frontal sinus is contained within frontal bone.

____________ are extension of frontal bone.

Internal (hidden) Bones of the Cranium

• Sphenoid Bone – – Forms ____________ portion of the cranium and contains the pituitary fossa, which houses the ____________ gland.

Contains the sphenoidal sinus in most animals.

INTERNAL (hidden) BONES OF THE CRANIUM

• Ethmoid Bone – – – Located rostral to sphenoid bone.

Contains _____________ plate which has branches of olfactory nerve passing through.

Horses and humans also have ethmoidal sinus in the ethmoid bone.

Bones of the Ear (Ossicles)

• Hidden in the middle ear from the outside in: – – – ____________ hammer ____________ anvil ____________ stirrup • Function is to transmit vibrations from the tympanic membrane (eardrum) to cochlea where vibrations are changed into nerve impulses.

Bones of the Face

• External (landmark) Bones of the Face – – – – – – Incisive (2) Lacrimal (2) Mandible (1 or 2) Maxillary (2) Nasal (2) Zygomatic (2) • Internal (hidden) Bones of the Face – – – – Palantine (2) Pterygoid (2) Turbinates (4) Vomer (1)

•

External Bones of the Face

Incisive: – Also called pre__________ bones – – Most ___________ skull bones In common domestic animals, this bone houses upper incisor teeth. (Ruminants have a dental pad instead) • Nasal: – Forms the _________ of the nose.

– Length depends on the animal.

External Bones of the Face

• Maxillary – – – Form the ________ jaw with incisive bone House all teeth besides incisors Forms rostral part of ________ palate – contains maxillary sinus • Lacrimal – Two bones that form medial portion of the ________ of the eye.

– Contains lacrimal sac which is part of tear system.

•

External Bones of the Face

Zygomatic – aka malar bones – form portion of orbit – join with temporal bone to form zygomatic ______ • Mandible – lower jaw – – houses all lower teeth only __________ skull bone – forms TMJ with temporal bone – 2 bones come together at mandibular ________________ • fused into one bone in horses and swine – 2 parts: ramus and shaft • • Ramus = caudal, vertical part Shaft = contains teeth, horizontal part

Internal Bones of the Face • ____________________ Bones: – Make up caudal part of _____ palate • ____________________ Bones: – Support part of the lateral walls of the ________ (throat).

• ____________________Bone: – Forms part of nasal septum (midline wall between left and right nasal passages).

• _____________________: – – Also called nasal conchae.

Thin and scroll-like that fill most of nasal cavity space.