Axial Skeleton

Question 1

List the vertebral formulas for Canine, Equine, and Bocine.

Answer 1

Canine: C7, T13, L7, S3, Cd 20-23
Equine: C7, T18, L6, S5, Cd 15-21
Bovine: C7, T13, L6, S5, Cd 18-20

Question 2

How does C1 differ from other cervical vertebrae?

Answer 2

Atlas. Lacks a spinous process. Lateral shelf-like transverse processes (wings). Articulates with the skull to form the “Atlanto-Occipital Joint” (yes joint)

Question 3

How does C2 differ from other cervical vertebrae?

Answer 3

Axis. Elongated, ridge-like spinous process, cranially the body projects forward in a peg-like eminence (dens). Articulates with the atlas to form the “Atlantoaxial Joint” (no joint)

Question 4

How does C6 differ from other cervical vertebrae?

Answer 4

High spine, ventral lamina of the transverse process

Question 5

How does C7 differ from other cervical vertebrae?

Answer 5

Lacks transverse foramina and has the highest cervical spine.

Question 6

How does T11 differ from other thoracic vertebrae?

Answer 6

Anticlinal Vertebrae. Spine is perpendicular to the long axis of the bone. All vertebral spines caudal to T11 point cranially. All vertebral spines cranial to T11 point caudally.

Question 7

Describe thoracic vertebrae T1-T9.

Answer 7

Dorsal spinous process. Transverse processes are short, blunt and irregular.

Question 8

Describe lumbar vertebrae.

Answer 8

Longer bodies than thoracic vertebrae, transverse processes are directed cranially and ventrolaterally.

Question 9

Describe the sacrum.

Answer 9

S1-S3 fused bodies and processes of these vertebrae form the sacrum. Lies between the ilia to articulate and form the Sacroiliac Joint.

Question 10

How does the equine and bovine sacrums differ from the dog’s?

Answer 10

Horse/Cow have 5 sacral bones.
Horse: Visible individual spinous processes.
Cow: Completely fused (like dog).

Question 11

What is an intervertebral disc? List the 2 components and describe these components.

Answer 11

Intervertebral discs are fibrocartilaginous structures between 2 vertebral bodies.
Nucleus Pulposus - soft center
Annulus Fibrosus - concentric layers of dense fibrous tissue surrounding nucleus pulposus

Question 12

How many pairs of ribs does the canine, equine and bovine have?

Answer 12

Canine: 13
Equine: 18
Bovine: 13
(one for each thoracic vertebra)

Question 13

What is the costochondral junction?

Answer 13

Where the dorsal bony part of the rib meets with the ventral cartilaginous part.

Question 14

Where do ribs 1-10 articulate?

Answer 14

Articulate with the costal fovea of 2 contiguous vertebrae and intervening fibrocartilage.

Question 15

Where do ribs 11-13 articulate?

Answer 15

Head articulates only with the cranial costal fovea of the transverse process of the same numbered vertebrae.

Question 16

What is the first sternebra called? The Last?

Answer 16

First: Manubrium
Last: Xiphoid Process.

Question 17

What are interspinous ligaments?

Answer 17

Connect adjacent spines above the arches

Question 18

What is the supraspinous ligament?

Answer 18

Longitudinal band of fibrous connective tissue that runs along the dorsal aspect of all spinous processes from the level of the 1st thoracic vertebrae through sacrum.

Question 19

What is the nuchal ligament? Which species do not have a nuchal ligament?

Answer 19

Cranial continuation of the supraspinous ligament, holds head up. Extends from the tip of the spinous process of T1 to the broad caudal end of the spine of C2 (Axis).
Cats, Pigs - no nuchal ligament

Question 20

What are intercapital ligaments?

Answer 20

Ribs 2-10. Where rib head articulates between vertebral bodies, connecting right and left rib heads. Extends across dorsal aspect of the annulus fibrosus ventral to the dorsal longitudinal ligament.

Question 21

What is the dorsal longitudinal ligament?

Answer 21

Runs from the axis to the sacrum on the ventral surface of the vertebral canal - widens where is attaches to the annulus fibrosus of the intervertebral discs.

Question 22

What is the ventral longitudinal ligament?

Answer 22

Runs from the axis to the sacrum on the ventral surface of vertebral bodies. Best developed in thoracic and lumbar regions.

Question 23

What is the dorsoscapular ligament (equine only)?

Answer 23

Laminae of thickened thoracolumbar fascia, gives rise to rhomboideus, serratus dorsalis cranialis, spenlius, etc.

Question 24

In the horse, where are the supraspinous bursa and the cranial/caudal nuchal bursas located?

Answer 24

Supraspinous: Between the supraspinous ligament and highest thoracic vertebra (T2 and T3) spinour processes.
Cranial and Caudal Nuchal Bursas: Between nuchal ligament and atlas (cranial) and axis (caudal).

Question 25

Where are the epaxial muscles located?

Answer 25

Lie dorsal to the transverse processes of the vertebrae.

Question 26

Where are the hypaxial muscles located?

Answer 26

All other muscles not included in the epaxial muscles. Located ventrally to the transverse processes - include abdominal and thoracic walls.

Question 27

List the 3 systems of the epaxial muscles from most lateral to most medial.

Answer 27

Iliocostalis System
Longissimus System
Transversospinalis System