Anatomy of the Back Lecture Flashcards
What does the spinal cord lie in?
Vertebral canal
What structure does the spinal cord end at?
Conus medullaris
What spinal level does the spinal cord end at in an adult and a child?
L1/L2 in an adult
L3 in a child
What do lumbar and sacral nerves form?
Cauda equina
What does the pia mater extend and attach to as?
Extends as the folum terminale and attaches to coccyx
What is the spinal cord covered and protected by?
Meninges
What are the 3 layers of the meninges (from outside to inside)?
Dura mater
Arachnoid
Pia mater
What is between the arachnoid and the pia mater?
Subarachnoid space
What is the subanarachnoid space filled with?
Cerebrospinal fluid
Where does the dura mater and arachnoid extend to?
S2
Why are the cervical and lumbar regions of the spinal cord enlarged?
To allow for brachial and lumbar plexes nerves that supply the limbs
Where do spinal nerves emerge in relation to vertebrae and what they are celled?
Above the vertebrae in Cervical - below in thoracic l lumbar and sacral
What does the lateral horn contain?
Cell bodies of the sympathetic neurones
Where is the lateral horn present?
Between T1-L2/3 (sympathetic)
Between S2-S4 (parasympathetic)
Where are grey matter and white matter in relation to each other in the spinal cord?
White is on the outside
Grey is on the inside
What pathway do sympathetic fibres take once they leave the spinal cord?
1) Emerge in the vental root via a white ramus
2) Synapse to the sympathetic chain
3) Re-enter spinal nerve via grey ramus
4) Distributed in both dorsal and ventral rami
Do sympathetic fibres emerge in the dorsal or ventral root?
Ventral
What does the sympathetic trunk extend from and to?
C1 to Cc1
What is thoracic viscera?
Organs in the thoracic cavity
What is abdominal viscera?
Organs in the abdomen
For which of thoracic and abdominal viscera do sympathetic fibres use the sympathetic chain?
Thoracic, they do no use the chain for abdominal viscera, fibres pass through the chain and synapse at prevertebral ganglia in the abdomen
What are the 2 ways that sympathetic fibres can go to the viscera as?
Post ganglionic (thoracic)
Pre ganglionic (abdominal)
What is viscera also known as?
Splanchnic nerves
Whre do splanchnic nerves to thoracic organs orginate?
T1 - T4
Where do splanchnic nerves to abdominal organs originate?
T5 - T12 and L1 - L2
What are the 3 kinds of splanchnic nerves?
Greater
Lesser
Least
Where do greater splanchnic nerves pass through the sympathetic chain?
T6 - T9
Where do lesser splanchnic nerves pass through the sympathetic chain?
T10 - T11
Where do least splanchnic nerves pass through the sympathetic chain?
T12
What happens to splanchnic nerves to thoracic organs after they synapse at the sympathetic chain?
Run to a nerve plexus (cardiopulmonary) as postganglionic fibres and then to they organ they innervate
What nerve plexus do splanchnic nerves to the thoracic organs use?
Cardiopulmonary plexus
How do sympathetic fibres innervate the face and head?
Synapse with one of three ganglia, then following an artery to reach their target organ
What are the 3 ganglia that sympathatic fibres use to innervate the face and head?
Superior cervical ganglion
Middle cervical ganglion
Inferior cervical ganglion
Is the sympathetic system generally considered motor or sensory?
Motor
How do sensory fibres of the sympathetic system run?
General sensory run with parasympathetic fibres
Pain runs with sympathetic fibres (also parasympathetic in pelvis)
They then enter the dorsal root, and continue to the lateral horn
Where do parasympathetic nerves arise from?
Cranial III, VII, IX and X
S2 - S4
Where are the S2 - S4 nerves commonly refered to as?
Pelvic splanchnic nerves
What are the pelvic splanchnic nerves?
Parasympathetic
Where do the pelvic splanchnic nerve cell bodies reside?
Lateral grey horn at T12 - L2
How do pelvic splanchnic nerves get from T12 - L2 to where they are needed?
1) Bilaterally, run through the lumbosacral plexus to the sacral foramina
2) Exit at the cauda equina at S2 - S4
3) Run through pelvic/inferior hypogastric plexus
4) Synapse to ganglion close to target
5) Postganglionic fibre supplies organ
Where do parasympathetic fibres exit the vertebral column?
Cauda equina at S2 - S4
How do parasympathetic fibres get from S2 - S4 to their ganglion close to their target?
Run through the pelvic/inferior hypogastric plexus
What does the pelvic/inferior plexus contain?
Sympathetic and parasympathetic fibres
What is the sentinal lymph node?
First lymph node to which cancer cells disperse
What are axillary lymph nodes?
Lie along the walls of the axilla
Where does the right lymphatic duct empty?
Junction of right internal jagular and right subclavian veins
Where does the thoracic duct empty?
Junction of left internal jagular and left subclavian veins
What is the cisterna chyli?
Most inferior part of the thoracic duct
What does the thoracic duct drain?
Whole body except right upper quadrant
What does the right lymphatic duct drain?
Only the right upper quadrant of the body
