Veterinary Anatomy: The Vertebral Column

Vertebral Column

Composed of approximately 50 irregular vertebrae.

Cervical Vertebrae

Seven vertebrae in most mammals, unique structures.

Atlas

First cervical vertebra, articulates with skull.

Axis

Second cervical vertebra, features dens process.

Third Cervical Vertebra

Spinous process length increases from third to fifth.

Fourth Cervical Vertebra

Similar to third, with slight structural differences.

Fifth Cervical Vertebra

Longest spinous process among cervical vertebrae.

Sixth Cervical Vertebra

Higher spinous process, unique transverse processes.

Seventh Cervical Vertebra

Lacks transverse foramina, highest spinous process.

Thoracic Vertebrae

Thirteen vertebrae, shorter bodies than cervical or lumbar.

Cervical Ribs

Articulate with seventh cervical vertebra's transverse processes.

Dens

Peglike eminence on the axis, also called odontoid.

Spinous Process

Projection from vertebrae, varies in length.

Transverse Processes

Lateral extensions of vertebrae, vary in structure.

Laminae

Part of vertebrae, size decreases in cervical series.

Costal Foveae

Articulation points for true ribs on vertebrae.

Caudal Articular Processes

Features on vertebrae, decrease in prominence.

Ventral Arch

Structure of the atlas, supports skull.

Irregular Bones

Type of bone comprising the vertebral column.

Articular Surfaces

Contact points where vertebrae connect.

Cranial and Caudal

Directional terms indicating head and tail ends.

Costal Fovea

Cranial and caudal depressions for rib articulation.

Foveae Costales Transversales

Articulating surfaces on transverse processes.

Mamillary Processes

Paired projections starting from second thoracic vertebra.

Accessory Processes

Developed in midthoracic region, absent in lumbar 5-6.

Articular Processes

Located at junctions of pedicles and laminae.

Spinous Processes

Highest and most massive in midlumbar region.

Transverse Processes (Lumbar)

Directed cranially and ventrally, longest in midlumbar.

Accessory Processes (Lumbar)

Well developed on first three lumbar vertebrae.

Articular Processes (Lumbar)

Lie in sagittal planes, restrict lateral flexion.

Sacral Vertebrae

Three vertebrae fuse to form the sacrum.

Sacrum

Wedge-shaped bone between ilia, articulates with them.

Body of Thoracic Vertebrae

Possesses costal foveae for rib attachment.

Size Variation (Thoracic)

Foveae decrease in size from first to last.

Body of Lumbar Vertebrae

Longer than thoracic, increases in width.

Length of Lumbar Vertebrae

Seventh lumbar matches first in length.

Cranial Inclination

Spinous processes have slight cranial tilt.

Palpable Transverse Processes

Broad extremities felt in emaciated animals.

Caudal Vertebral Notches

Overlapped by accessory processes in lumbar region.

Sagittal Plane Orientation

Lumbar articular processes restrict lateral movement.

First Sacral Segment

Larger than combined bodies of other segments.

Median Sacral Crest

Fusion of three spinous processes.

Apex Ossis Sacri

Broad caudal extremity articulating with first caudal vertebra.

Dorsal Sacral Foramina

Transmits dorsal sacral spinal nerves and vessels.

Intermediate Sacral Crest

Formed by processes and connecting ridges.

Cranial Articular Processes

Large processes forming joints with seventh lumbar vertebra.

Pelvic Surface of Sacrum

Variable concavity of sacral surface.

Wing of Sacrum

Enlarged lateral part with auricular surface.

Auricular Surface

Articulates with the ilium.

Lateral Sacral Crest

Thin crest terminating in a pointed process.

Caudolateral Angle

Flattened pointed process at the end of lateral crest.

Base of Sacrum

Cranially facing part of the sacrum.

Sacral Canal

Wide canal formed by fused vertebral foramina.

Pelvic Sacral Foramina

Larger foramina located lateral to fused bodies.

Promontory

Transverse ridge on the base of the sacrum.

Caudal Vertebrae

Typically 20 vertebrae, varying from 6 to 23.

Body of First Caudal Vertebra

Equal width and length, first in series.

Length Variation in Caudal Vertebrae

Segments lengthen then shorten towards the tail.

Cranial Articular Processes in Caudal Vertebrae

Present but non-functional in caudal vertebrae.

Mamillary Process

Process present until articular function disappears.

Hemal Arches

Separate bones articulating with caudal vertebrae.