Companat: Chapter 2 Part 1

Skeleton of the head, Vertebral Column, Skeleton of the thorax

The axial skeleton comprises the:

Neural part

(cranium, neurocranium),

Facial part

(facies, viscerocranium),

Skull, Mandible, Hyoid apparatus

Skeleton of the head with:

Skull

forms a rigid construction composed of many bones, which are mostly paired.

Skull

encompasses and protects the brain and the sensory organs of sight, smell, sound, balance and taste.

Upper respiratory and alimentary tracts

These are lodged within the skull.

Bony projections

Forms attachments for the facial and masticatory musculature

Sutures

individual bones of the skull are firmly united by

Articular Joints

the lower jaw (mandible) and the hyoid apparatus are attached to the skull by

bony components

of the vertebral bodies are derived from the axial, perichondral mesenchymal of the sclerotomes.

intervertebral discs

considered to be remnants of this original tissue.

embryological precursor

of the vertebral body forms a bony arch dorsally, thus completing the central foramen of the vertebra, which encloses the spinal cord.

vertebral column

as a whole consists of a series of separate bones, the vertebrae

Skull to the tip of the tail

The vertebral column extends from?

Foramen magnum, Sacral Canal

Where the spinal column begins and ends

vertebral column

serves to support the body and takes over a central function

Ribs

The cranial thoracic vertebrae of the vertebral column are supported by the

Muscles and Tendons

The ribs are linked to the thorax by?

Pelvic Region

the vertebral column is firmly joined to the pelvic limb by the articulation of the sacral wings to the ilia.

Thoracic Vertebrae

The ribcage is composed of this dorsally.

Sternum

The ribcage is composed of this ventrally.

Ribs

The ribcage is composed of this laterally.

Ligaments, Chondral Junctions, True Articulation

The thorax form the bony components of the thoracic wall and are joined functionally by a variety of

rib cage

encloses the thoracic cavity and is kept under tension by its surrounding muscles.

Truncated Cone

The thorax of the domestic mammals has the shape of a laterally compressed

Neural Part

The bones of the neural or cranial part of the skull enclose the cranial cavity

Brain, Meninges, Blood Vesssel

The cranial cavity has:

Cranium

Collection of many smaller bones, that fit together in a species specific construction.

Skulls

differ largely, not only between different species and breeds, but also between individuals of the same breed, age and sex.

Unpaired basioccipital bone, Unpaired basisphenoid and presphenoid bones

the floor is composed of the:

Unpaired supraoccipital bone and exoccipital bones

the nuchal wall is composed of the:

Paired temporal bone

the lateral walls are composed of the:

Unpaired Frontal Bone, Unpaired Parietal Bone, Unpaired Interparietal Bone

the roof is composed of the:

Unpaired ethmoid bone

the nasal wall is composed of the:

Occipital Bone

forms the nuchal wall of the skull and can be divided into the basilar part, the squamous part and the lateral parts

Basilar, Squamous, Lateral

Divisions of the Occipital Bone

Occipital Bone

These bones form a ring surrounding the spinal cord, the foramen magnum.

Basilar Part

constitutes the caudal part of the base of the cranium

Basilar Part

situated rostral to the foramen magnum, where it is joined to the basisphenoid by a cartilagenous suture

jugular foramen

Located on either side of the basilar part, adjacent to the tympanic bullae

Tymphanic Bullae

The jugular foramen is located on either side of the basilar part, adjacent to the

deep petro-occipital fissure

In the pig and the horse the sharp and thin lateral borders of the basilar part form the

squamous part

situated dorsal to the lateral parts and the occipital condyles, completing the foramen magnum dorsally

Nuchal Line

• In ruminants, the nuchal crest is reduced to the prominent

Cerebrospinal Fluid

The nuchal crest is easily palpable and can be used as a landmark, together with the wings of the atlas, for the collection

External Sagittal Crest

well-defined median ridge

External Sagittal Crest

arises from the nuchal crest in carnivores and the horse

external occipital protuberance

are median triangular projections with the base pointing towards the base of the cranium

Nuchal Ligamenrt

The external occipital protuberance provides attachments to:

Lateral Parts

form the lateral borders of the foramen magnum.

atlanto-occipital joint

They include the occipital condyles, which articulate with the atlas to form the

paracondylar processes

provide attachment to the specific muscles of the head.

Lateral to the condyli process

The location of the paracondylar process

Elongated

The paracondylar process in pigs

Bulb shaped

The condylar processes in carnivores

Shorter

The condylar processes in ruminants and horses

Sphenoid Bone

forms the rostral part of the base of the neurocranium and consists of two similar segments

Presphenoid

Sphenoid bone rostrally

Basisphenoid

Sphenoid Bone Caudally

Median Body, Lateral wings

Sphenoid bone is composed of

Cartilaginous suture

In humans these bones fuse firmly in early life, while in adolescent domestic mammals they are separated by a

Sphenoid Bone

considered as individual bones in veterinary anatomy.

Presphenoid

constitute the bony parts of the rostral cranial fossa and articulate with the basisphenoid caudally

Basisphenoid

constitute the bony parts of the medial cranial fossa

pterygoid processes

arise from the rostral border of the basisphenoid.