Anatomy Exam 2

What is the typical vertebral formula for a dog?

C7

T13

L7

S3

Cd20

What are the processes of the typical cervical vertebrae

6 joints

• 2 cranial articular processes

• 2 caudal articular processes

• 1 spinous process

• 2 transverse processes

How many pairs of ribs does a typical dog have?

13 (9 pairs of true ribs, 3 pairs of floating/false ribs, 1 pair of floating ribs)

What is the difference between true, false, and floating ribs?

True ribs connect directly to the sternum via coastal cartilage

False ribs do not connect directly to sternum. cartilage fuses together

Floating ribs do not attach to the sternum and ends in abdominal muscles

What kind of joint is at the rib head/vertebrae?

Synovial

Which cervical vertebrae are unique?

C1 = atlas

C2 = axis

C6 = expanded ventral laminae (on transverse process)

C7 = articulates with first pair of ribs (has extra joint pair)

Which thoracic vertebrae are unique?

T11 = anticlinal

• T1-T10 incline caudally

• T12 and 13 incline cranially

all have a transverse process that articulates with rib tubercles

Which qualities in lumbar vertebrae are unique?

• longer bodies than thoracic

• transverse processes are oriented cranially and ventrolaterally

What are the unique qualities of the atlas (C1)?

articulates with skull.

transverse processes ARE the wings.

reduced body.

lateral vertebral foramina is where 1st pair of cervical spinal nerves exit the spine

What are the unique qualities of the axis?

long spinous process.

dens.

What are the unique qualities of C6?

expanded ventral laminae on the transverse process

What are the unique qualities of C7?

articulates with the first pair of ribs (rib tubercle)

What are the unique qualities of T11?

anticlinal

What is the normal function, location, and structure of the intervertebral discs

fibrocartilaginous

• annulus fibrosus = fibrous ring. thicker on ventral side

• nucleus pulposus = gelatinous

stabilize adjacent body structures and act as cushions

What are the 4 long ligaments of the vertebral column?

Nuchal lig

Supraspinous lig

Dorsal longitudinal lig

Ventral longitudinal lig

What are the attachments and function of the nuchal lig?

Axis - T1

• Elastic tissue (appears yellow)

• support head

• NOT present in cats

What are the attachments and function of the supraspinous lig?

T1 - sacrum

• collagenous

What are the attachments and function of the dorsal longitudinal lig?

Axis - sacrum

• collagenous

What are the attachments and function of the ventral longitudinal lig?

Axis - sacrum

• collagenous

What is the location and function of the intercapital ligaments?

Located between rib head and contralateral pair. made of collagen and goes over top of IV discs

Where is intervertebral disc disease (IVDD) most likely to occur in a dog? Why?

cervical and lumbar regions, and T11-13

In the cervical region, they can be strained due to neck flexibility/movement

In the thoracolumbar region, they can have high stress due to being in a spot that is starkly more flexible than the vertebrae immediately before it.

What are the three main parts of the rib? Where do they articulate?

Head, neck, tubercle

• Head articulates with the vertebral body(ies)

  • Ribs 1-9 are attached to 2 verts

  • Ribs 10-13 are attached to 1 vert

• Tubercles articulate with transverse process of thoracic vert (costal fovea)

• Ends of ribs articulate with costal cartilage/sternum

What is the costal arch and which ribs are involved?

Cartilaginous joining of ribs 9-12

What are the major joints of the axial skeleton? What type of joints are they?

Intervertebral disc joints - fibrocartilaginous

cranial articular processes - synovial

caudal articular processes - synovial

How many joints do C3-C6 have, and which joints are they?

6 joints

• 2 IVD

• 2 cranial articular processes (L/R)

• 2 caudal articular processes (L/R)

How many joints does C7 have, and which joints are they?

8 joints

• 2 IVD

• 2 cranial articular processes (L/R)

• 2 caudal articular processes (L/R)

• 2 with the rib heads of Rib pair 1 (L/R)

How many joints do T1-T10 have, and which joints are they?

12 joints

• 2 IVD

• 2 cranial articular processes (L/R)

• 2 caudal articular processes (L/R)

• 2 rib heads at cranial end (L/R)

• 2 rib heads at caudal end (L/R)

• 2 with rib tubercles at the transverse process (L/R)

How many joints does T12 & T13 have, and which joints are they?

10 joints

• 2 IVD

• 2 cranial articular processes (L/R)

• 2 caudal articular processes (L/R)

• 2 rib heads at cranial end (L/R)

• 2 with rib tubercles at the transverse process (L/R)

What is the difference between epaxial and hypaxial muscles?

Epaxials are dorsal to the transverse process

Hypaxials are ventral to the transverse process

What are the hypaxial muscles of the neck?

1. sternocephalicus

2. sternohyoideus

3. scalenus

What are the attachments and action for sternocephalicus m.?

sternum - bones of skull

depress head/neck and draw them laterally

What are the attachments and action for sternohyoideus m.?

sternum - basihyoid bone

pulls tongue and larynx caudally

What are the attachments and action for scalenus m.?

transverse process of cervical vert - cranial side of ribs 1-3

inspiration

What are the muscles of the thoracic wall?

1. serratus dorsalis cranialis m.

2. external intercostal m.

What are the attachments and action of the serratus dorsalis cranialis m?

dorsal raphe - proximal side of ribs 1-10

inspiration

What are the attachments and action of the external intercostal m.?

caudoventrally directed muscle fibers between adjacent ribs

inspiration

What are the muscles of the abdominal wall?

1. internal intercostal m.

2. diaphragm

What are the attachments and action of the internal intercostal m.?

cranioventrally directed muscle fibers between adjacent ribs, intercostal muscles move during inspiration

inspiration

What is the purpose of the diaphragm?

inspiration

What is the muscle of expiration (muscle of the thoracic wall)? What does it do?

Serratus dorsalis caudalis m.

attached from dorsal raphe to ribs 10-13 (proximal aspect)

pulls last ribs caudally during expiration

What is the muscle fiber orientation of the intercostal muscles?

External intercostals run caudoventrally

Internal intercostals run cranioventrally

What are the three epaxial muscle systems?

Transversospinalis, Longissimus, Iliocostalis

What are the muscles within the transversospinalis system? Where are they located in reference to the spine? Where do they attach?

Closest to midline. Runs from skull to ilium

Semispinalis capitis, splenius, thoracic, lumbar

What are the muscles within the longissimus system? Where are they located in reference to the spine? Where do they attach?

Between T and I systems. Runs from skull to ilium

Longissimus capitis, longissimus cervicis, longissimus thoracis, lumbar part

What are the muscles within the iliocostalis system? Where are they located in reference to the spine? Where do they attach?

Directly on top of transverse process. Runs from Rib 1 to ilium

Iliocostalis thoracis, iliocostalis lumborum

Which is more medial- longus capitis or longus colli?

Longus colli

What are the cranial and caudal boundaries of the thoracic cavity?

Cr: thoracic inlet

Cd: diaphragm

What are the lateral boundaries of the thoracic cavity?

ribs and intercostal muscles

What are the dorsal and ventral boundaries of the thoracic cavity?

D: bodies of the thoracic vert

V: sternebrae

What is the difference between the thoracic and pleural cavities?

Thoracic is the whole space inside the rib cage (heart, lungs, …)

Pleural is the smaller space within the thoracic cavity. It is between the two layers of pleura that cover the lungs/chest wall

What are the three different regional divisions of pleura?

Visceral = lines lungs

Parietal = lines body wall

Connecting = double layer of pleura

What is visceral pleura also called?

Pulmonary pleura

What are the 4 different kinds of parietal pleura in the thoracic cavity?

Costal = covers ribs and intercostals

Mediastinal = reflects on midline and covers midline structures

Pericardial mediastina = covers the heart/makes up part of pericardial sac

Diaphragmatic = covers cranial part of diaphragm

What is the main connecting pleura in the thoracic cavity? What does it do?

Pulmonary ligament on the caudal lung lobes. Connects bronchus to mediastinum

How many pairs of nerves emerge from intervertebral foramina in the spine?

35 pairs

What is the breakdown of the different nerve pairs that emerge from intervertebral foramina?

8 cervical

13 thoracic

7 lumbar

3 sacral

What is the path that a nerve stimulation signal goes (starting at sensory input at the paw)?

1. sensory input (ie: something hot)

2. ventral branch

3. spinal nerve

4. dorsal root

5. spinal cord** (intermediolateral gray horn)

6. ventral root

7. motor stimulation to move the foot

**at the spinal cord, a signal goes to an interneuron in gray matter to stimulate a response to keep the opposite leg down/weight bearing (while the other leg is being lifted)

What is mesothelium? What are the main examples (3) of mesothelium in the body?

simple squamous epithelial layer that secretes serous fluid to prevent friction

Pleura, pericardium, peritoneum

Which structures make up the central nervous system?

brain and spinal cord

What are the two aspects of the peripheral nervous system?

cranial nerves and spinal nerves

How many cranial nerves are there?

12 pairs

How many spinal nerves are there? Where do they emerge from?

35 pairs. emerge from intervertebral foramina

Define an efferent neuron

Motor input

Takes signal away from CNS and to tissue

Define an afferent neuron

Sensory input

Takes signal away from tissue and to the CNS

What are the two types of efferent motor neurons?

GSE (general somatic efferent) and GVE (general visceral efferent)

What does a GSE neuron do?

supplies voluntary skeletal muscles of the head, trunk, limbs

sends signals from CNS to main body

What does a GVE neuron do?

supplies involuntary smooth muscles of visceral organs, cardiac muscle, glands, and blood vessels

sends signals from CNS to main body

Which nerves contain GSE neurons?

CN 3, 4, 6, 12 + all spinal nerves

Which nerves contain GVE neurons?

CN 3, 7, 9, 10, 11 + all spinal nerves

What are the five types of afferent neurons?

GSA (general somatic afferent), GVA (general visceral afferent), SSA (special somatic afferent), SVA (special visceral afferent) and proprioception

What does a GSA neuron do?

talks to GSEs

sends signals from main body to CNS (pain, temp, touch)

Which nerves contain GSA neurons?

CN 5 + all spinal nerves

What does a GVA neuron do?

talks to GVEs

sends signals from blood vessel walls + organs to the CNS

also responds to chemical stimuli and distention

Which nerves contain GVA neurons?

CN 7, 9, 10, + all spinal nerves

What does a SSA neuron do?

sends vision and auditory signals to the CNS

receptors are NOT located near surface of the skin

Which nerves contain SSA neurons?

CN 2, 8

What does a SVA neuron do?

sends olfactory and taste signals to CNS

Which nerves contain SVA neurons?

CN 1, 7, 9, 10

What does a proprioceptive neuron do?

detects position of head, trunk, limbs

Which nerves have proprioceptive neurons?

CN 5, 8 + all spinal nerves

Which nerve type is most associated with motor neurons?

multipolar

Which nerve type is most associated with sensory neurons?

pseudounipolar

Which nerve type is most associated with special senses?

bipolar

Which nerve comes out through the lateral vertebral foramen?

Nerve 1C

Which nerve comes out through C2-C7? Where do they exit the spinal cord?

Nerves 2C-8C

Exit BEFORE the vertebrae with the same number (4C exits at the intervertebral foramina between C3 and C4)

Which nerve exits between C7 and T1?

Nerve 8C

Which nerves exit between T1 - 5Cd?

The rest (lol). They come out BEHIND the vertebra of the same number (4T exits at the intervertebral foramina between T4 and T5)

What is the cauda equina?

a collection of nerves tapering off of the spinal cord

What is the difference between ANS, CNS, and PNS?

CNS and PNS are locations. ANS is a function of the nervous system

What are the two names for a collection of nerve cell bodies?

Ganglion = nerve cell body group outside the CNS

Nucleus = nerve cell bodies inside the CNS (like KP nuclei!)

Define the parasympathetic nervous system and describe the neuron pattern.

rest and digest. homeostasis.

long presynaptic neuron, short postsynaptic neuron (inside the wall of the organ)

Define the two physical locations of the origin of the parasympathetic nervous system

CN 3, 7, 9, 10 (brainstem) and S1, S2, S3 (sacral spinal cord)

What is the sympathetic nervous system and what is the nerve pattern?

Fight or flight

no consistent trend in neuron length

What is the main physical location of the origin of the sympathetic nervous system?

T1-L5

What do the thoracic spinal nerves innervate?

T1 & T2 = brachial plexus

T3, T4, T5 = chest wall (breathing)

T6, T7, T8 = chest and upper/mid abdomen

T9, T10, T11, T12 = lower abdomen

What is the location for the internal thoracic a.? What does it branch from? Which of its branches gets blood farther up the rib?

immediately caudal to the ribs

branches from the internal thoracic a.

dorsal branches of the internal thoracic a. get blood farther up the rib (towards the spine)

What muscle would lose its sole nerve supply if CN11 (accessory) was damaged?

Trapezius m.

What are the main lymph nodes of the neck/thorax?

superficial cervical (ake prescapular), axillary, and tracheobronchial

Where is the superficial cervical lymph node found?

under omotransversarious and brachiocephalicus. cranial to supraspinatus

Where is the axillary lymph node found? What is special about it?

above deep pectoral. behind the axillary vein.

most afferent lymph vessels in the thoracic wall + deep limb structures will drain here