Week 7 Flashcards
How many pairs of cranial nerves are there? do they consist of motor or sensory nerves? Where do they emerge from?
12 crainial nerves.
3 are primarily sensory: CN1 (Olfactory), CN2 (Optic), CN8 (Accoustovestibular)
4 are primarily motor: CN4 (Trochlea), CN6 (Abducens), CN11 (Accesory), CN12 (Hypoglossal)
5 are mixed (both M and S): CN3 (occulomotor), CN5 (Trigeminal), CN7 (Facial), CN9 (Glossopharangeal), CN10 (Vagus)
Emerge through skull foramina
How many Spinal Nerves are there? Explain the sensory and motor makeup of these nerves. Where do they emerge from?
31 PAIRS
All are sensory and motor (I.e. Mixed)
Emerge through intervertebral foramina
What sort of information do the peripheral nerves send? Explain both of the general pathways of both the Somatic and Autonomic NS’s.
I feel like this image explains it mega well so yeh
Explain the composition of the white matter to gray matter in the SPINAL CORD. where are the dorsal and ventral horns? There is also another horn present in some spinal cord segments, what is this known as and what segments is it present in?
White matter is SURROUNDING the gray matter (i.e the gray matter makes up the horns CENTRALY)
The dorsal horn is posterior and the ventral horn is anterior.
The third horn is known as the Ventral Horn and is present in spinal cord segments T1-T12, L1-L2 and S2-S4.
Label numbers 1-9. Explain what makes up number 3. Does 4 or 5 have more branches, why?
- Dorsal Rootlets
- Dorsal Nerve root
- Dorsal Root Ganglion (Consists of nerve cell bodies of sensory nerves)
- Dorsal Primary Ramus (less branches)
- Ventral Primary Ramus (more branches cause it innervates more)
- Grey and white rami communicantes
- Mixed spinal nerve
- Ventral nerve root
- Ventral rootlets
Sensory components enter the spinal cord via _______ spinal nerve root. Motor components exit the spinal cord via ________ nerve root. They join to produce ________ spinal nerve.
Sensory components enter the spinal cord via Dorsal spinal nerve root. Motor components exit the spinal cord via Ventral nerve root. They join to produce Mixed spinal nerve.
Cell bodies for sensory neurons (somatic and autonomic) are in the ____________________. Cell bodies for motor neurons are located in the _____________________. Cell bodies for autonomic motor neurons are located in the _________________.
Cell bodies for sensory neurons (somatic and autonomic) are in the Dorsal Root Ganglion. Cell bodies for motor neurons are located in the Anterior Horn of gray matter. Cell bodies for autonomic motor neurons are located in the Lateral horn of gray matter.
Name numbers 1-11.
- Spinal Cord
- Pia Matter
- Subarachnoid space
- Arachnoid Mater
- Dura Mater
- Intervertebral Foramina
- Dorsal Primary Ramus (D.P.R)
- Ventral Primary Ramus (V.P.R)
- Extradural fat (or Epidural Fat)
- Extradural Space
- Posterior Longitudinal Ligament
Name Numbers 1-6
- Dorsal Cutaneous Ramus
- Dorsal Primary Ramus
- Mixed Spinal Nerve
- Anterior Cutaneous branch of V.P.R
- Ventral primary Ramus (V.P.R)
- Lateral Cutaneous branch of V.P.R
Explain the different groups of spinal nerves explaining:
- how many pairs
- which vertebrae they are within
- Where they emerge from
- 8 Pairs of cervical nerves Emerge from above C1 to C7 with the 8th cervical nerve emrging from above T1 and below C7 because well, ya know, we dont have an 8th cervical vertebrae.
- 12 pairs of thoracic nerves that emerge from below T1-T12 vertebrae
- 5 Pairs of lumbar nerves that emerge from below L1-L5 vertebrae.
- 5 Pairs of sacral nerves from anteriorSacral foramina (VPR) or posterior sacral foramina (DPR).
- 1 Pair of coccygeal nerves from Co1 that emerge from the sacral hiatus
Explain what is meant by segmented supply in relation to somatic nerve distribution
One spinal cord segment supplies one area, this means that the nerve has contributions from only one spinal cord segment. It follows the segmental pattern of development and is usually involved in Simple movments (unlike muscles of the upper limb for example that require integrated plexuses to achieve more complicated shit).
Explain what is meant by integrated supply in relation to somatic nerve distribution
It is when a number of spinal cord segments supply an area in order to achieve complex coordinated muscle activity. A plexus is the most common example as we have two very common plexuses known as the lumbosacral plexus and the brachial plexus (there are more) that are responsible for the mojority of upper and lower limb movements. Instead of refering to the nerves by the segments, for integrated supplies we usually name the nerve by what its innervating to avoid having to name each root segment involved; i.e. the Musculocutaneous nerve from the brachial plexus which involves nerves C5,C6, and C7.
Explain the innervation for the Dorsal Primary Rami.
Innervate all postvertebral (epaxial) muscles as well as the dorsal skin.
List the Fate of the Ventral primary rami, explaining the different plexuses or segments that they will become. (explain root levels for both categories)
Couldnt be fucked just re-writing exactly what this says
What is meant by a “dermatome” ?
The unilateral area of skin innervated by the fibres of a single spinal nerve.
E.g. The Single Spinal nerve of S1 will innervate the skin of the medial portion of the entire length of the posterior thigh, then the lateral portion of the calve and then the lateral foot including the 5th digit as it heads inferiorly.
What is meant by the term Myotome?
The unilateral muscle mass receiving innervation by one
spinal nerve.
Muscles that developed in an epaxial position (epimere) will be supplied by _________. Muscles that developed in an hypaxial position (hypomere) will be supplied by ___________.
Muscles that developed in an epaxial position (epimere) will be supplied by Dorsal Primary Rami. Muscles that developed in an hypaxial position (hypomere) will be supplied by Ventral Primary Rami.
Explain what happens to muscles that migrate from an epaxial to hypaxial and also muscles that migrate from hypaxial to epaxial?
Muscles that migrate from an epaxial to hypaxial position ‘drag’ their nerve (dorsal primary ramus) with them. E.g. Levator Costarum
Muscles that migrate from a hypaxial position to an epaxial position ‘drag’ their ventral primary ramus with them. E.g. Levator Scapulae, Serratus post, sup and Inf, and latissimus dorsi.
What nerve branches are responsible in supplying the skin of the thoracic wall?
Anterior and Lateral Cutaneous branches
What supplies the posterior skin of the thorax?
The segmental Dorsal Primary Ramus (also supplies the post verteberal muscles of that region)
Explain the Posterior and Anterior aspects of each intercostal space’s blood supplywithin the thoracic wall? Explain how these arteries “interconnect”.
Posterior Aspect: Posterior Intercostal Artery (and its collateral branch). The intercostal spaces 1 and 2 are supplied via the superior intercostal artery from the costocervical trunk that is a branch of the subclavian artery. Intercostal Spaces 3-11 are supplied directly from the descending thoracic aorta, And finally the 12th intercostal space is supplied by the posterior intercostal artery known as the subcostal artery.
Anterior Aspect: Via the Anterior Intercostal Arteries that arise from the internal thoracic artery.
Terminal and collateral branches of the posterior intercostal artery anastomose with the anterior intercostal artery
Label numbers 1-3
- Superior Intercostal Artery
- Right Subclavian Artery
- Costocervical Trunk
For The Internal Thoracic Artery :
- What artery does it arise from?
- How does it travel?
- Where does it terminate?
- What does it divide into upon termination?
- Explain what is supplied? (Be specific)
- Arises from subclavian Artery
- Descends into the thorax lateral to the sternum, anterior to the transversus thorasis muscle.
- Terminates in the 6th intercostal space
- Upon termination it divides into the musculophrenic artery and the superior epigastric artery.
- I.C spaces 1 - 6 are supplied by the internal intercostal artery, I.C. spaces 7 - 9 are supplied by the musclulophrenic artery, and quite interestingly there is not anterior supply to the 10th and 11th space nor the subcostal space as they are fully supplied by the posterior intercostal artery.
Explain the venous drainage system of the posterior thoracic wall. how does the right sides venous drainage differ from the left? what do they have in common? (probs the worst card in the deck for sure. mega boring. gonna forget bout it within 4 seconds post trunk exam)
Both Sides: 1st posterior IC vein is drained by the supreme intercostal vein directly into the brachiocephalic vein. The 2nd and 3rd posterior IC veins are drained by the superior intercostal vein, which then on the right side drains into the azygos vein, and on the left side the Superior intercostal vein drains into the left brachiocephalic vein.
Right Side: 4th to 11th posterior IC veins + subcostal vein drain directly into the azygous vein.
Left Side: 4th to 8th posterior IC veins drain to accesory hemiazygous vein then into the azygous vein (at T8). 9th to 11th posterior IC veins are subcostal veins drain into the hemiazygous vein and then into the azygous vein (at T9).
The Azygous Vein drains into the Superior Vena Cava at the sternal Angle (T4/T5)
Label veins 1-10
- Left brachiocephalic Vein
- Left superior intercostal Vein
- Accesory hemiazygous Vein
- Left posterior intercostal veins
- Hemiazygous vein
- Right subcostal vein
- Right posterior intercostal veins
- Azygous Vein
- Right superior intercostal vein
- Right brachiocephalic vein
For the Cisterna Chyli:
- What is it?
- How often is it present?
- Where is it located?
- What is it the union of?
- What is it the origin of?
- It is a lymphatic duct
- Present in about 15-50% of individuals
- Usually anterior to L1/L2
- Union of the left and right lumbar trunks (lymphatic vessels from the pelvis and lower limbs) and the intestinal trunk (Lymphatic vessel from the GUT)
- Origin of the thoracic duct
For the Thoracic Duct:
- What makes it significant?
- What parts does it drain?
- explain its location
- What does it drain into?
- Largest Lymph vessel
- Drains lymph from left side of body + right side below thorax
- In midline /right below T4 and crosses at the sternal angle
- Drains into left venous angle (junction between left internal jugular vein and left subclavian vein)
For the right lymphatic duct:
- roughly where is it?
- What does it drain?
- What does it drain into?
- around/below T4
- Drains right upper quadrant above diaphragm
- Drains into right venous angle (junction between right internal jugular vein and the right subclavian vein)
Explain the passageway for the thoracoabdominal nerves in regards to innervating the abdominal wall.
Thoracoabdominal nerves continue inferiorly from the intercostal spaces crossing deep to the costal margin into the neurovascular plane of the abdomen. (between the internal oblique and transverse abdominis).
Explain the innervation for the ainterolateral abdominal wall muscles. What is the exception?
All anterolateral abdominal wall muscles are innervated by the thoracoabdominal, subcostal, iliohypogastric and ilioinguinal nerves. EXCEPT the cremaster muscle; which is supplied by the genitofemoral nerve.
Explain the innervation of the abdominal cutaneous structures. (both anteriorly and laterally).
Anteriorly: Supplied by the thoracoabdominal nerve which is from the anterior cutaneous branches. There are also some contributions from the iliohypogastric and ilioinguinal nerve.
Laterally: Supplied by the thoracoabdominal nerve which branches from the lateral cutaneous branch.
Explain the nerve supply to the skin of the posterior abdominal wall.
Nerve supply: Segmental Dorsal Primary Rami as with the post vertebral (epaxial) muscles of that region.
Explain the blood supply of the anterolateral abdominal wall. Where do these vessels arise from?
Supplied by 3 main vessels: Superior epigastric, Inferior epigastric, and the musculophrenic artery.
- The superior epigastric artery arises from the internal thoracic artery, and the inferior epigastric artery arises from the external iliac artery. (they anastamose)
For the lumbar arteries:
- Where do they arise from?
- How many pairs are there?
- Where do they travel?
- What muscles are they covered by?
- What do they anastomose with?
- Arise from the abdominal Aorta
- 4-5 pairs
- Run posteriorly around the lumbar vertebral bodies and then anteriorly in the neurovascular plane
- Covered by psoas and quadratus lumbroum
- Anastomose anteriorly with the superior and inferior epigastric arteries.
Explain the general venous drainage of the posterior abdominal wall.
Lumbar veins drain directly into the Inferior Vena Cava.
Explain the general venous drainage of the anterior abdominal wall.
Basically the same as the arteriolar supply but in reverse; The superior epigastric vein drains into the internal thoracic vein and the inferior spigastric vein drains into the external iliac vein.
Explain the nerve supply to the pelvic floor and wall. (Include the individual muscles and nerves)
All 4 muscles that make up the floor and wall will be innervated by the ventral rami of the sacral plexus with a little help from the coccygeal plexus.
Pelvic Wall:
- Obturator internus: L5, S1 and S2
- Piriformis: S1 and S2
Pelvic Floor:
- Coccygeus: S4 and S5
Levator Ani: S4, Nerve to levator ani, and coccygeal plexus
Explain the blood supply to the pelvic floor and perineum. Be sure to include the divisions and branches. (might help to draw a division tree).
So, blood supply to the pelvic floor and perineum is via the branches of the internal iliac artery; The anterior and posterior divisions. The anterior division branches further to become the inferior gluteal artery (to supply the pelvic diaphragm) and the Internal pudendal artery (to supply the perineum).
