BMS 301 Unit 2

Describe the numerical difference between the cervical vertebrae, cervical spinal cord segments and cervical spinal nerves

Cervical:

• Vertebrae: 7

• Spinal Cord Segments: 8

• Spinal Nerves: 8

How many vertebrae are there for the four vertebral segments?

Cervical: 7

Thoracic: 12

Lumbar: 5

Sacral: 5

What are the unique structural characteristics of the cervical vertebrae?

Transverse foramina

Bifid process on C2

What are the unique structural characteristics of the thoracic vertebrae?

Facets for ribs (costals)

What are the unique structural characteristics of the lumbar vertebrae?

Intervertebral foramina between individual vertebral bodies

What are the unique structural characteristics of the sacral vertebrae?

Fused

What are the two general vertebral joints, where are they located, what’s their function and what types are they?

Superior/Inferior Articular Processes

• Location: Two on top and two on the bottom of each vertebrae

• Type: Gliding synovial

• Function: Communicate with adjacent vertebrae

Intervertebral Discs

• Location: Between each individual vertebral body

• Type: Cartilaginous

• Function: Flexion and extension

What are the three special vertebral joints, where are they located and what types are they?

Atlantoocipital

• Location: Between superior aspect of C1 vertebrae and occipital bone of the skull

• Type: Synovial gliding “yes” joint

Atlantoaxial

• Location: Between inferior aspect of C1 and superior aspect of C2

• Type: Synovial pivot “no” joint

Sacroiliac

• Location: Between articular surface of sacrum and articular surface of ilium

• Type: Synovial gliding joint

What are the four curvatures of the spine and when during life do they appear?

• Cervical Curvature: Acquired second when the infant can support the weight of its own head 

• Thoracic Curvature: A primary curvature present in the fetus 

• Lumbar Curvature: Acquired third when the infant assumes an upright position 

• Sacral Curvature: A primary curvature present in the fetus 

What are the three problems with curvatures and where do they occur?

• Thoracic Kyphosis: Exaggerated thoracic curvature 

• Lumbar Lordosis: Exaggerated lumbar curvature 

• Scoliosis (full spine): Exaggerated lateral curvature

What are the five connective tissue ligaments? Include their location, continuous or non-continuous and their action.

Anterior Longitudinal Ligament

• Location: Anterior to vertebral bodies

• Continuous

• Action: Limits extension of the vertebral column

Posterior Longitudinal Ligament

• Location: Posterior to vertebral bodies, anterior to the spinal cord

• Continuous

• Action: Limits flexion of the vertebral column

Interspinous Ligament

• Location: Between spinous processes

• Non-Continuous

• Action: Limits flexion of the vertebral column

Supraspinous Ligament

• Location: Posterior to all spinous processes

• Continuous

• Action: Limits flexion of the vertebral column

Ligamenta Flava

• Location: Between the lamina of vertebrae

• Non-Continuous

• Action: Limits rotation, flexion and lateral flexion of the vertebral column

What are the two portions of an intervertebral disc?

Annulus Fibrosus- External

• Tough tissue

Nucleus Pulposus- Internal

• Squishy-jelly like shock absorber between each vertebrae

What is a slipped/Herniated Disc?

Slipped/Herniated Disc = Nucleus pulposus ruptures out of the annulus fibrosus

• Doesn’t rupture anterior due to anterior longitudinal ligament

• Ruptures posteriorly and laterally because posterior longitudinal ligament is very thin

• Hits and damages the next lowest spinal nerve between vertebrae

Define extrinsic back muscles

Muscles that start and end in a different place

• Attach from vertebrae to upper limb bones

Define intrinsic back muscles

Muscles that start and end in the same place

• Start and stop in the vertebral column, skull and ribs (axial skeleton)

What is the superficial intrinsic back muscle? Include the location, innervation and action

Splenius Muscle

• Location: Thoracic and cervical vertebrae to skull

• Innervation: Posterior rami of spinal nerves

• Action: Bilateral neck extension, lateral flexion, rotation

What are the three intermediate intrinsic back muscle? Include the location, innervation and action

Spinalis Muscle (most medial)

• Location: Spinous process to spinous process

• Innervation: Posterior rami of spinal nerves

• Action: Bilateral extension of the trunk, lateral flexion

Longissimus Muscle

• Location: Transverse process to transverse process

• Innervation: Posterior rami of spinal nerves

• Action: Bilateral extension of the trunk, lateral flexion

Iliocostalis Muscle

• Location: Sacrum/Ilium to ribs

• Innervation: Posterior rami of spinal nerves

• Action: Bilateral extension of the trunk, lateral flexion

When together, what are the three intermediate intrinsic back muscles called? Where do they run from?

Erector Spinae Muscles

• Sacrum to skull

What is the deep intrinsic back muscle? Include the location, innervation and action

Transversospinalis Muscle

• Location: Transverse process to spinal process

• Innervation: Posterior rami of spinal nerves

• Action: Bilateral extension of the trunk, unilateral rotation

What are the two enlargements of the spinal cord?

Cervical Enlargement: Neurons that innervate the upper limb

Lumbar Enlargement: Neurons that innervate the lower limb

Why do spinal cord enlargements happen?

More spinal cord means more neurons

More neurons are needed to go out to the upper limb (around cervical) and lower limb (around lumbar)

Define Conus Medularis

The end of the spinal cord

Why does the spinal cord taper off?

• Fetal Life: Spinal cord matches up and spinal nerves exit directly below, spinal cord ends at S5

• Birth: Vertebrae continue to grow after the spinal cord has stopped growing in length, spinal cord ends at L2 with no spinal cord at L3/L4

Define Cauda Equina

Nerve roots forming from end of spinal cord (inferior to the conus medularis) through vertebrae

Define Lumbar Cistern

Space below the Conus Medullaris

What are the three meninges?

Dura Mater

• Outermost layer 

Arachnoid Mater 

• Spider-web like film over spinal cord

Pia Mater (deepest)

1. Filum Terminale 

• Inferiorally anchors spinal cord to sacrum 

2. Denticulate Ligaments 

• Laterally anchors spinal cord

What are the three spaces between the meninges?

Subdural Space 

• Between dura mater and arachnoid mater 

• Potential space 

• Blood can enter and cause damage 

Epidural Space 

• Between dura mater and vertebrae 

• Real space that holds fat and veins 

• Where epidurals are given 

Subarachnoid Space 

• Real space that holds CSF 

• Between pia mater and arachnoid mater, surrounding denticulate ligaments  

1. Lumbar Cistern 

• Subarachnoid space inferior to conus medullaris 

• Real space that holds CSF 

• Where spinal taps are taken

What are the posterior, lateral, anterior, inferior and superior boundaries of the thoracic wall?

Posterior: Thoracic vertebrae

Lateral: Ribs

Anterior: Sternum and costal cartilages

Inferior: Respiratory diaphragm muscle

Superior: Thoracic inlet

Detail the arterial supply of the anterior thoracic wall

• Right/Left subclavian artery

• Right/Left internal thoracic artery

• Right/Left anterior intercostal arteries

Detail the arterial supply of the posterior thoracic wall

• Thoracic/descending aorta

• Right/Left intercostal arteries

• Left/Right posterior intercostal arteries

Detail the venous return of the thoracic wall

Anterior Intercostal Veins

• Internal thoracic veins

• Subclavian veins

Posterior Intercostal Veins

• Azygos vein

Both come together at the superior vena cava

T/F: Intercostal nerves are preceded by anterior/posterior

FALSE

• Intercostal nerves originate from the anterior rami (motor and sensory) of thoracic spinal nerves 

• All come from spinal cord and wrap around (no anterior starting point) 

• No anterior/posterior intercostal nerve as its the same, singular nerve wrapping around

What are the three large compartments of the thoracic cavity?

1. Right Pulmonary Cavity 

• Holds right lung 

2. Mediastinum 

• Holds everything in the thorax that’s not a lung 

• E.x. Heart, aorta, phrenic nerves, vagus nerves, azygos vein, etc

3. Left Pulmonary Cavity 

• Holds left lung

What are the levels of the lungs?

1. Trachea: C-shaped cartilage rings

2. Left/Right Primary Bronchus: Go to each lung

3. Secondary/Lobar Bronchi: One for each lobe of the lung (right: 3, left: 2)

4. Tertiary Bronchi

5. Bronchioles: Non-cartilaginous

6. Alveoli: Where gas exchange occurs

When does inspiration occur?

When atmospheric pressure exceeds interpulmonary pressure

What are the three ways to increase thoracic volume?

1. Superior/Inferior: Diaphragm flattens, thoracic cavity becomes taller, volume increase

2. Anterior/Posterior: Ribs elevate, sternum moves forward, volume increases

3. Left/Right: Ribs elevate, chest widens, volume increases

Detail the flow of blood through the heart

To Lungs: Inferior/superior vena cava, right atrium, right AV valve, right ventricle, pulmonary valve, pulmonary trunk, left/right pulmonary arteries, lungs

To Body: Pulmonary veins, left atrium, left AV valve, left ventricle, aortic valve, ascending aorta, aortic arch, descending aorta (aka thoracic aorta)

Define the Chordae Tendineae

Anchor the atrioventricular valve to the papillary muscles, preventing valve prolapse and backflow of blood into the atria during ventricular systole

Define the Papillary Muscles

Contract to tighten the chordae tendineae, preventing the AV valves from prolapsing (inverting) into the atria during ventricular contraction

What is the arterial supply of the coronary circulation

Ascending aorta

Left Coronary Artery

• Anterior interventricular branch

• Circumflex branch

Right Coronary Artery

• Posterior interventricular branch

• Right Marginal Branch

What is the venous return of the coronary circulation

Great cardiac vein and middle cardiac vein

Coronary sinus

Right atrium

What is the ductus venosus shunt, what does it bypass, connect and become?

Ductus Venosus

• Bypasses: Liver

• Connects: Umbilical vein to inferior vena cava

• Becomes: Ligamentum Venosum

What is the ductus foramen ovale, what does it bypass, connect and become?

Foramen Ovale

• Bypasses: Lungs

• Connects: Right atrium to left atrium

• Becomes: Fossa ovalis

What is the ductus Ductus Arteriosus, what does it bypass, connect and become?

Ductus Arteriosus

• Bypasses: Lungs

• Connects: Pulmonary trunk to aorta

• Becomes: Ligamentum Arteriosum

What are the superior and inferior boundaries of the abdominal wall?

Superior: Lower ribs, xiphoid process, T10

Inferior: Iliac crest, pubic symphysis, L5

What are the superior and inferior boundaries of the abdominal cavity?

Superior: Respiratory diaphragm

Inferior: Iliac crest, S1

What is the innervation of the abdominal wall

Anterior/ventral rami of spinal nerve

What is the arterial supply to the posterior abdominal wall/muscles and what do the arteries arise from?

The lumbar arteries that arise from the descending aorta

What is the arterial supply to the anterior abdominal wall/muscles and what do the arteries arise from?

• The superior epigastric arteries that arise from internal thoracic arteries

• Inferior epigastric arteries that arise from external iliac arteries

What are the three flat muscles?

1. External abdominal oblique muscle

2. Internal abdominal oblique

3. Transversus abdominis

What are the boundaries of the external abdominal oblique muscle?

A: Ribs

B: Iliac crest, pubis and inguinal ligament

What are the boundaries of the internal abdominal oblique muscle?

A: Ribs and thoracolumbar fascia

B: Iliac crest, pubis and inguinal ligament

What are the boundaries of the transversus abdominis?

A: Ribs and thoracolumbar fascia

B: Iliac crest, pubis and inguinal ligament

What are the four layers of the flat muscles?

1. External abdominal oblique

2. Internal abdominal oblique

3. Transversus abdominis

4. Transversalis fascia

What are the A and B attachments and the innervation of the psoas?

A: Lumbar vertebra

B: Lesser trochanter of the femur

Innervation: Femoral nerve

What are the A and B attachments, innervation and action of the iliacus?

A: Iliac fossa of ilium

B: Lesser trochanter of the femur

Innervation: Femoral nerve

Action: Primary flexors of the hip

What are the A and B attachments, innervation and action of the quadratus lumborum?

A: Lower ribs and lumbar vertebra

B: Iliac crest

Innervation: Thoracic/lumbar spinal nerves

Action: Bilateral extension of the trunk and unilateral flexion of the trunk

What passes through the inguinal canal for males vs females?

Males: Spermatic cord

Females: Round ligament of the uterus

Where is the superficial inguinal ring in the flat muscles?

Its the external opening in the external abdominus

Where is the deep inguinal ring in the flat muscles?

It is the internal opening in the transversalis fascia

Why is an inguinal hernia more common in males?

The spermatic cord is larger in diameter than the round ligament of the uterus so there is an increased chance of other contents getting out

Which of the following are paired

 

phrenic nerve.

 sympathectic trunk (chain).

 umbilical artery

 brachiocephalic vein.

 coronary sinus.

phrenic nerve.

 sympathectic trunk (chain).

 umbilical artery

 brachiocephalic vein.

The liver, pancreas and gallbladder all secrete into the duodenum. What do they secrete and what route do they take?

Liver secretes bile via the bile ducts

Gallbladder secretes stored bile via the bile ducts

Pancreas secretes enzymes via the pancreatic duct

Where does the parasympathetic nervous system arise from in the CNS?

Craniosacral division

• Brainstem (CN III, VII, IX, X)

• Sacral spinal cord (S2-S4)

Where does the sympathetic nervous system arise from in the CNS?

Thoracolumbar division

• Thoracic spinal cord (T1-T12)

• Lumbar spinal cord (L1-L2/L3)

Define mesentery

A double layer of peritoneum that suspends the intestines

Which two GI organs have endocrine and exocrine functions and what are these functions?

Pancreas

• Endocrine: Sends insulin into the blood to reabsorb glucose

• Exocrine: Digestive enzymes go into a duct that go into the duodenum

Liver

• Endocrine: Releases proteins, clotting factors and nutrients into the blood

• Exocrine: Produces bile that goes into a duct