Axial

What does the axial skeleton comprise?

The skeleton of the head, vertebral column, and thorax.

What are the two main parts of the skull?

The neural part and facial part.

What bones are included in the cranium (neural part) of the skull?

Frontal bones, interparietal bones, occipital bone, parietal bones, temporal bones, ethmoid bone, and sphenoid bone.

What forms the nuchal wall of the occipital bone?

The occipital bone consists of basilar, squamous, and lateral parts.

How does the nuchal crest differ between ruminants and other animals?

It is reduced as the nuchal line in ruminants.

What is the external sagittal crest?

A well-defined median ridge found in carnivores and horses.

How do the paracondylar processes differ among species?

Elongated in pigs, short in ruminants and horses, and bulb-shaped in carnivores.

What are the components of the sphenoid bone?

Presphenoid (rostral) and basisphenoid (caudal), each with a body and wing.

What notches does the basisphenoid form in horses?

Carotid, oval, and spinous notches.

What is the significance of the temporal bone?

It has three parts: squamous, petrosal, and tympanic, and includes features for hyoid attachment.

What is the process present in pigs that serves as an attachment for the hyoid apparatus?

Nuchal Process

What is the process present in horses and ruminants that serves as an attachment for the hyoid apparatus?

Styloid Process

What forms the tympanic cavity?

The tympanic bulla of the temporal bone, which encloses the auditory ossicles.

How does the temporal fossa differ in ruminants?

It is pushed to the left side by the frontal bone.

What does the frontal bone consist of?

Frontal squama, temporal surface, orbital part, and nasal part.

What is the significance of the temporal line?

Separates the frontal and temporal surfaces, prominent in certain species.

Which species have an interparietal bone?

Only present in horses and cats.

What role does the ethmoid bone play in the skull?

Partly forms both cranial and facial parts and has a role in olfactory nerve bundles.

What are ethmoturbinates?

Delicate bony scrolls that arise from the ethmoid bone.

How do dogs, ruminants, horses, and pigs differ in their endoturbinates and ectoturbinates?

Dogs have 4 endoturbinates and 6 ectoturbinates, ruminants have 4 endoturbinates and 18 ectoturbinates, horses have 6 endoturbinates and 25 ectoturbinates, and pigs have 7 endoturbinates and 20 ectoturbinates.

What forms the lateral walls of the facial part of the skull?

Lacrimal bones, zygomatic bones, and maxilla.

What forms the floor of the nasal cavity?

Palatine bones, maxilla, incisive bone, and vomer.

What is the roof of the nasal cavity formed by?

Frontal and nasal bones.

How do the rostral processes of the nasal bone differ among species?

They end centrally in pigs, sheep, horses, laterally in carnivores, and have separate apices in oxen.

What does the zygomatic bone form?

Part of the bony orbit and the zygomatic arch; articulates with the frontal and maxilla.

What role does the maxilla play in the facial skeleton?

It is the largest bone of the face, forming part of the lateral walls, nasal and oral cavities, and hard palate.

What are some openings related to the infraorbital foramen in various species?

In horses, at the nasoincisive notch; in oxen, 3 cm dorsal to the 1st maxillary cheek tooth; in dogs, 1 cm dorsal to the 3rd maxillary cheek tooth.

What do paranasal sinuses include?

Air-filled cavities within some skull bones, including frontal and maxillary sinuses.

What forms the mandible?

Consists of the body and ramus.

What parts make up the body of the mandible?

Alveoli and mental foramina.

What does the ramus of the mandible include?

Coronoid process, condylar process, and angular process.

How is the mandible joined?

It consists of two halves joined by a median mandibular symphysis.

How does the median mandibular symphysis differ in pigs and horses?

It is complete in pigs and horses.

What is a key feature of the mandible in carnivores and ruminants?

It remains bipartite.

What is the function of the hyoid apparatus?

Serves as a suspensory mechanism for the tongue and larynx.

What bones comprise the hyoid apparatus?

Basihyoid, thyrohyoid, and ceratohyoid.

How is the basihyoid structured?

Short and unpaired at the base of the tongue, with a long lingual process in horses and short in ruminants.

What is unique about the thyrohyoid in ruminants and horses?

It is firmly fused with the thyroid cartilage of the larynx.

What does the suspensory apparatus of the hyoid articulate with?

The temporal bone in a species-specific manner.

What is the general structure of the tympanohyoid in carnivores?

It is fibrous, whereas in other animals it consists of short cartilaginous tissue.

How do carnivores and pigs differ in their epihyoid structure?

In pigs, it is replaced by the epihyoid ligament, and in carnivores, it remains cylindrical.

What is the general structure of the vertebral column?

Includes cervical, thoracic, lumbar, sacral, and coccygeal vertebrae.

What is unique about the first cervical vertebra (C1)?

It is called the atlas and lacks a body.

What distinguishes the second cervical vertebra (C2)?

It has a dens and caudal articular facet.

How do cervical vertebrae vary among carnivores and ruminants?

Carnivores have an alar foramen and notch, while ruminants have transverse foramen on C1.

What is the spinous process like in carnivores?

It is elongated and overhangs the cranial and caudal end of the body.

How does the shape of spinous processes differ among species?

They vary, being confluent in carnivores and horses but not in pigs and ruminants.

What is notable about the thoracic vertebrae?

They have bodies with costal fovea for rib attachment.

How do the spinous processes of thoracic vertebrae vary among horses, oxen, and pigs?

They are long and narrow in horses, long and wide in oxen, and irregular in pigs.

What defines an anticlinal vertebra?

It is where the spinous process changes from rising to falling; located at T10 for dogs, T12 for pigs, and T13 for oxen.

What is the composition of the lumbar vertebrae?

They have longer bodies without costal facets, and spinous processes inclined cranially.

What do sacral vertebrae form?

They fuse to form the sacrum.

How is the form of the sacrum in carnivores compared to other animals?

It is quadrilateral in carnivores and triangular in other species.

What are the caudal vertebrae characterized by?

First few resemble lumbar vertebrae; the rest are reduced to simple rods.

What is the pygostyle?

A fusion of caudal vertebrae that provides support to the rectrices in birds.

What does the bony pelvis consist of?

Composed of right and left hip bones, firmly attached to the synsacrum.

What forms the acetabulum?

The joint of the ilium and ischium.

What is the significance of the sternum?

It comprises sternebrae joined by intersternal cartilages.

How many sternebrae do carnivores have?

Carnivores have 8 sternebrae.

How does the sternum differ in birds?

It is a large, unsegmented bone with a prominent keel.

What is the function of the vertebrae in the axial skeleton?

They protect the spinal cord and provide structural support to the body.

How are the cervical vertebrae structured in terms of movement?

They allow for a wide range of motion in the neck.

What unique feature do thoracic vertebrae possess compared to other vertebrae?

They have facets for rib attachment.

What is the role of the hyoid bone?

It supports the tongue and assists in swallowing.

What components form the pelvis?

The hip bones, sacrum, and coccyx.

How does the structure of the sacrum differ in various species?

It varies in shape; quadrilateral in carnivores and triangular in others.

What is the primary role of the maxilla in the skull?

It houses the upper teeth and forms part of the nasal and oral cavities.

What distinguishes the mandible's body in different species?

The mandible's body varies in shape and attachment points based on species.

What are the key features of the tympanic bulla?

It is a part of the temporal bone that encloses the auditory ossicles.

Why is the sphenoid bone important in the skull?

It connects the cranial and facial skeleton and houses the pituitary gland.