What are the two major parts of a typical vertebra?
Body & arch
List the seven processes of a typical vertebra.
1 spine 2 transverse processes 4 articular processes (2 cranial & 2 caudal)
Where do the spinal nerves leave the vertebral canal?
Intervertebral foramen
What is formed by all the vertebral foramina of all the vertebrae?
Vertebral canal
What is the laminae of a vertebrae?
Roof (top of arch) of vertebral foramen
What is the interarcuate space?
Dorsal gap between adjacent vertebral arches
With what does the atlas (C1) articulate?
Occipital condyles of skull
What are the large lateral masses of the atlas?
Wings of the atlas (transverse processes)
What peg-like process on the axis forms a pivot articulation with the atlas?
Dens
What is the large ventral projection of the sixth cervical vertebra?
Transverse process ("sled")
What joint is formed by the atlas and the skull?
Atlanto-occipital joint, "yes" joint
The articulation of the axis with the atlas is known as the ___ joint.
Atlantoaxial joint, "no" joint
Name the fibrocartilages between the bodies of adjacent vertebrae.
Intervertebral discs
What are the two parts of an intervertebral disc?
Annulus fibrosus and nucleus pulposus
What elastic connective tissue structure attaches the 1st thoracic spine to the spine of the axis (C2) in the dog?
Nuchal ligament, none in cat
What elastic tissue fills the dorsal space (interarcuate space) between the arches of adjacent vertebrae?
Ligamentum flavum, interarcuate or yellow ligament
What connects the heads of a pair of opposite ribs, crossing the dorsal part of the intervertebral discs?
Intercapital ligament
What are the two paired "strap muscles" of the neck?
Sternohyoideus and sternothyroideus muscles
Name the muscle extending from the sternum to the head.
Sternocephalicus muscle
What forms "envelopes" around the muscles of the neck?
Deep fascia of neck.
What muscles are above the transverse processes of the vertebrae?
Epaxial mm.
Name the two major epaxial muscles of the back?
Iliocostalis and longissimus mm.
What muscles are below the vertebrae's transverse processes?
Hypaxial muscles
What is the hypaxial muscle in the neck and cranial thorax?
Longus colli m.
What is the main hypaxial/sublumbar muscle of the abdomen?
Psoas major m.
Where is the common carotid artery located?
Besides the trachea in carotid sheath.
What glandular structures are under the omotransversarius muscle just cranial to the shoulder?
Superficial cervical (prescapular) lymph node
List the two important structures enclosed in the carotid sheath.
Common carotid artery, vagosympathetic trunk
Where is the esophagus located in the middle of the neck?
on left
What is the gland just caudel to the larynx on the trachea?
Thyroid gland
What is the part of the hyoid apparatus crossing the midline?
Basihyoid bone
Name the five divisions of the spinal cord.
Cervical, thoracic, lumbar, sacral & caudal
What are the ascending and descending tracks of the spinal cord and what do they carry?
Ascending - sensory information Descending - upper motor neurons (UMN), motor information
Where does the spinal cord end in the dog?
Dog : L6 (6-7)Cat : S1-3Human : L2
Ventral branches of spinal nerves interlace to form ____.
Plexuses
What nerve travels along the dorsal border of the omotransversarius muscle?
Accessory nerve (CrN 11)
What plexus supplies some of the extrinsic and all of the intrinsic muscles of the thoracic limb?
Brachial plexus
Plexuses are formed by the ventral branches of spinal nerves in every region except which?
Thorax (except T1-2) = intercostal nn.
The ventral branches of the thoracic nerves T3-13 do not form a plexus, but pass in the intercostal spaces as _____ nerves.
Intercostal
What plexus supplies the abdominal wall, pelvic limb, external genitalia, rump and perineum?
Lumbosacral plexus
What forms the spinal nerve? Into what do spinal nerves divide?
Roots (dorsal & ventral) Branches (dorsal & ventral)
How do spinal nerves leave the vertebral canal?
Through intervertebral foramen
What spinal nerve branches supply sensation from the skin of the abdominal wall?
Dorsal : upper flank (including area below transverse processes)Ventral : rest
What are the six major functional regions of the spinal cord?
Cranial cervical (C1-5) Cervical (brachial) enlargement (C6-T1) Thoracic and cranial lumbar (T2-L3) Lumbar (lumbosacral) enlargement (L4-S2) Sacral (S2-3) Caudal (Ca1-5)
What does the sacral region of the spinal cord supply?
Reflex control of urination, defecation, sexual reflexes & parasympathetic outflow
Where does the spinal cord end in the dog? cat?
Dog : about L6-7Cat : sacrum
What is the function of the proprioceptive fibers?
Sense position of body parts to each other and to environment
Over what structures do proprioceptive fibers travel?
Peripheral nn., spinal cord, brain stem to cerebellum & cerebrum
What is a dermatome? autonomous zone?
Area of skin innervated by a nerve, only 1 spinal n. respectively
What are upper (UMN) and lower motor neurons (LMN)?
LMN's : leave CNS as peripheral nervesUMN's : in CNS, affect LMN's
What is the function of most UMN (upper motor neurons)?
Inhibit spontaneous activity of LMN until action desired
LMN's are ______ ______ without the input of UMN's.
spontaneously active
List the meninges from outer to inner.
Dura mater, arachnoid & pia mater
List the spaces that are related to the meninges.
Epidural : between dura mater and periosteumSubdural : potential space between the dura mater and arachnoidSubarachnoid space : between the arachnoid and pia mater (CSF)
What is the enlargement of the subarachnoid space between the medulla oblongata and cerebellum?
Cisterna magna (cerebellomedullary cistern)
What fills the gap between the dorsal edge of the foramen magnum and the atlas?
Dorsal atlanto-occipital membrane
What is the unpaired artery running longitudinally on the vertebral canal floor in the ventral median fissure the length of the spinal cord?
Ventral spinal artery
What are the paired, thin-walled, valveless vessels on the vertebral canal floor in the epidural space from the skull to the caudal vertebrae?
Internal vertebral venous plexus
What are the vessels located on the ventral surface of the tail?
Median caudal artery & vein
How are the dorsal and ventral edges of the vertebral canal checked in back radiographs?
Check for alignment, they should be straight lines without step defects
What should be evaluated in the area of the axis and atlas?
The dens (odontoid process), it should be present and held in the ventral vertebral canal
How are the intervertebral disc spaces in back radiographs evaluated?
Triads (3 adjacent spaces) are compared for size differences
Describe the appearance of the intervertebral foramen, considered "windows" to the spinal cord.
Look like Snoopy's little bird buddy "Woodstock" or a "horse head" in profile
How are the intervertebral foramen compared in back radiographs?
For differences due to disc space differences
What is a landmark in a lateral film of the caudal neck?
"SLEDS" or tranverse process of C6
How does a myelogram appear?
Subarachnoid space lights up = two white lines (columns) separated by a space (the invisible spinal cord)
What may narrowing of the intervertebral space indicate?
Protruded disc
Describe the three possible types of spinal cord lesion.
a. Extradural lesion : outside the dura materb. Intradural lesion : between spinal cord and dura materc. Intramedullary (spinal cord) lesion : inside cord
What are the myelogram findings for the following lesions?
a. Thinning or break of columns pushed inward at lesion, +- expanded cord/thinned columns in other view b. Widening of subarachnoid space, +- expanded cord/thinned columns in other view c. Expanded cord/thinned columns in all views
What are the myelogram findings for the following lesions?
a. Thinning or break of columns pushed inward at lesion, +- expanded cord/thinned columns in other view
What are the myelogram findings for the following lesions?
b. Widening of subarachnoid space, +- expanded cord/thinned columns in other view
What are the myelogram findings for the following lesions?
c. Expanded cord/thinned columns in all views
What is the disease of the cervical vertebrae in large breeds causing stenosis of the vertebral canal resulting in ataxia (unsteady gait)?
Cervical spondylomyopathy, canine wobbler disease
What is excessive ventral lumbar curvature?
Lordosis (swayback)
What is an excessive thoracic curvature?
Kyphosis (hunchback in humans)
What is lateral curvature to the spine?
Scoliosis
What clinical problem would a fractured dens cause?
Spinal cord injury
What is the removal of the right or left dorsal vertebral arch (lamina) to relieve pressure in the spinal canal?
Hemilaminectomy
What is a hemivertebra?
Wedge-shaped vertebra resulting in severe angulation to spine in thoracolumbar region.
Define and give another name for Wobbler's disease.
Cervical sponylomyelopathy - cervical spinal cord compression
What are seen radiographically with spondylosis?
Spurs : osteophytes intervertebral spacesBridges (ankylose vertebrae)
What is diskospondylitis?
Infection of IV discs & adjacent vertebrae
What is another name for vertebral osteomyelitis/vertebral abscess?
Spondylitis
What is spina bifida?
Failure of 1 or more vertebral arches to close
Basically what are the two types of intervertebral disease?
Type 1 : disk ruptureType 2 : disk bulging
A slipped disc results when the soft ___ ___ is squeezed to one side of the disc, causing the firm ___ ___ to protrude and possibly rupture.
Nucleus pulposus Annulus fibrosus
What can a slipped disc protruding into the vertebral canal compress?
Spinal nerves or spinal cord itself
Where is the annulus fibrosis thinnest?
Dorsally
Why don't intervertebral disc commonly impinge on nerves in most of the thoracic region?
Protection of intercapital ligaments
Where is rupture of an intervertebral disc common?
Thoracolumbar junction (T11-L2)
Basically, what are the two types of intervertebral disease?
What is the removal of the remaining nucleus pulposus from a rupture disc?
Disc fenestration
What is the surgery for cervical disc disease?
Ventral decompression through longus colli m. to remove extruded disk
What is the surgery for thoracolumbar disk disease?
Dorsal laminectomy/hemilaminectomy & fenestration (remove nucleus pulposus)
What is atlantoaxial subluxation/instability?
Instability of C1-C2 joint due to dens problems (absence, malformation, failure to ossify or insufficient ligamentous support of the dens, rupture of ligaments of dens or fracture of dens)
How would you place a tube for an emergency tracheostomy / tracheotomy?
Skin incision in the ventral neck, separate the strap mm., cut between the cartilages of the trachea, insert tube
Why can a broken neck result in respiratoy paralysis?
Phrenic nerve to diaphragm arises in brachial & cervical plexuses
Why is the jugular vein often used preferentially in venipuncture?
Saves easier cephalic v. for emergencies
What is a trans tracheal wash?
Injection & aspiration of material into a from the trachea for lab work
What is a myelogram?
Injecting contrast medium into the subarachnoid space & radiographing
Describe how a spinal tap or myelogram is done with a spinal needle.
Flex neck Palpate : wings of atlas, spine (axis) & external occipital protuberanceNeedle : midline, 1/2" cranial to line between wings, parallel to the caudal skullFeel "pop" (dorsal atlanto-occipital ligament) & immediately stop Pull out stylet & look for CSF fluid in the hub = right place (If hit bone, pull out and start again, or walk needle off bone into space CSF tap : collect CSF for analysisMyelogram : collect CSF for analysis & then inject contrast medium
Where are CSF taps performed?
Cisterna magna or lumbar cistern
Where is a lumbar CSF tap performed in the dog & cat?
L5-6 or forward or back 1 space
What are the landmarks used for cerebrospinal fluid taps at the atlanto-occipital junction?
Wings of the atlas, spine of the axis, external occipital protuberance
Describe doing a thoracolumbar myelogram or CSF (spinal) tap.
Needle between L5-6 spines Through yellow ligament into spinal canal - Midline critical Through canal to vertebrae Withdraw needle a little (mm) into ventral subarachnoid space Remove stylet to see CSF in hub if correct CSF tap : collect CSFMyelogram : collect CSF, then inject contrast
Where is epidural anesthesia given?
Through lumbosacral space into epidural space
What is the lumbosacral space?
Interarcuate space between last lumbar vertebrae (L7) & sacrum
Describe procedure for a epidural in the dog.
Thumb & third finger on cranial end of sacral tuberosities Palpate (index finger) space between last lumbar spinous process (L7) & sacrum Needle perpendicular, "pop" through yellow ligament into epidural space
What are the clinical signs of meningitis?
Cervical rigidity (due to pain [hyperesthesia]), fever and lameness
What is the term for meningitis associated with inflammation of the underlying spinal cord?
Meningomyelitis
How do lumbar, sacral and caudal spinal cord segments and the vertebrae relate?
They don't correlate with vertebrae of same number caudal to L4
Why is it important to know relationship between the lumbar spinal cord segments and the vertebrae they overlie?
To localize the spinal cord lesions
An easy way to remember where spinal cord segments lie in relationship to the vertebrae of the same number?
L3 over vertebrae L3 Sacral segments : over 5th vertebral (dog), sacrum (cat)
Where is the lesion if proprioception is lost?
Peripheral n., spinal cord, brain stem, cerebellum, or cerebrum (thus anywhere)
Does loss of proprioception localize the lesion?
No, but a sensitive indication of a neurological problem
How is proprioception evaluated clinically?
Postural reactions (e.g. knuckle paw)
Describe proprioceptive placing reaction in the dog and cat.
Placing the animal's weight on its dorsal paw should result in immediate adjustment to normal placement
How can knowing the spinal cord segments innervating myotomes and dermatomes be used clinically?
Used to localize lesions
Why should you palpate the entire body's muscles?
Check for muscle atrophy (head & limbs)
Why is a patellar tap performed in a physical exam?
Test reflex arc of pelvic limb
What easy, reliable reflexes are tested for peripheral reflex arcs?
Patellar tap, anal sphincter, tail bone, withdrawl reflex
How is the withdrawl reflex tested in a screening physical?
Pinch toes of all 4 limbs
Where does gait deficits without "head signs" localize the lesion?
To spinal cord, peripheral nerves, neuromuscular junction or diffuse muscular lesion
What is the term for weakness?
Paresis
What is complete to partial loss of voluntary motor activity?
Paralysis and paresis (weakness)
What suffixes are used to paresis and paralysis, respectively?
Define the following:
Only one limb involved
Define the following:
Both limbs on one side
Define the following:
All 4 limbs involved
Define the following:
Only the pelvic limbs involved
What is the effect of UMNs damage on LMNs?
LMNs increase their activity
What localizes a lesion to the peripheral nerves, or spinal cord, or segment of brain stem LMNs arise from?
LMN signs
What is the memory aid for LMN signs?
Thumbs down = everything decreased or disappears
List 4 LMN disease signs (thumb down).
Decreased or absent tone (hypotonia to atonia) Decreased to absent reflexes (hypo- to areflexia) Flaccid paralysis Rapid atrophy (neurogenic atrophy) 1 week
List 4 UMN disease signs (thumb up).
Normal to increased muscle tone Normal to increased reflexes (hyperreflexia) Spastic paresis to paralysis Slow (disuse) atrophy
What is Shiff-Sherrington syndrome?
Hyperextension of forelimbs with lesions to thoracic spinal cord (T3-L3 / area 3)
Localize the lesion:
C6-T2 (Area 2)
Localize the lesion:
C1-C6 (area 1)
Localize the lesion:
T3-L3 (Area 3) on left
Localize the lesion:
T3-L3 (area 3) + Shiff-Sherrington
Localize the lesion:
L4-S1 (area 4)
List presenting signs to transection of the spinal cord:
No LMN signs to either limb UMN & loss of proprioception to all 4 limbs
List presenting signs to transection of the spinal cord:
LMN & loss of proprioception to thoracic limb UMN & loss of proprioception to PL
List presenting signs to transection of the spinal cord:
Normal TL (+- Shiff-Sherrington) UMN & loss of proprioception to PL
List presenting signs to transection of the spinal cord:
Normal TL LMN & loss of proprioception to PL
What do ascending sensory / afferent tracts carry?
Sensory information including superficial & deep pain and proprioception
What is indicated if a toe pinch elicits a withdrawl of limb, but no behavioral change?
Spinal cord or brain stem lesion cranial to reflex center
What type of prognostic sign is loss of deep pain?
Bad prognostic sign
What is usually the first sign in spinal cord compression?
Loss of proprioception
Localize lesion:
Between T1 & S1
What is the cutaneous trunci (panniculus) reflex?
Normal reflex: contraction of cutaneous trunci m. in response to a pin prick of trunk
What is the path of the cutaneous trunci (panniculus) reflex?
Sensation from skin of trunk over thoracic & lumbar spinal nn. to spinal cord, up cord to lateral thoracic n. (C8), out to cutaneous trunci m.
Clinically what is the panniculus response used to evaluate?
Level of thoracic spinal cord damage
Where is the spinal cord damage if the panniculus response is absent caudal to the level of the 10th thoracic vertebrae?
Level of T8
Where are the dermatomes of the cutaneous trunci response located?
1 or 2 vertebrae caudal to level of innervating cord segment
What vessel is commonly used to bleed cattle?
Median caudal v. (tail v.)
What is a fibrocartilaginous embolism?
Emboli occlude vessels in the spinal cord
What clinical signs are seen with fibrocartilaginous embolism?
Paresis/paralysis caudal to the lesion
How is a presumptive diagnosis of fibrocartilaginous embolism made?
From symmetric paresis with normal radiology