Anatomy of labour Flashcards
What nerve modalities are found in the pelvis?
Sympathetic, parasympathetic and visceral afferent
What nerve modalities are found in the perineum?
Somatic sensory and somatic motor.
Superior aspect of pelvic organs, pain perceived where and which nerve roots?
Suprapubic pain
T11-L2, run alongside symp fibres
Inferior aspect of pelvic organs, pain perceived where and which nerve roots?
Perineal pain
S2,3,4, run alongside parasymp fibres
Structures that cross from pelvis to perineum, nerve modality if above levator ani:
S2,S3,S4 parasympathetic
Structures that cross from pelvis to perineum, nerve modality if below levator ani:
Pudendal nerve S2 S3 S4
Where is a spinal/epidural anaesthetic injected?
L3-L4 region
Anaesthatises cauda equina
Main benefit of epidurals?
No infection
Where does cauda equina start?
L2
Where does subarachnoid space end?
S2
Which layers does the needle pass through in a spinal anaesthetic?
Supraspinous ligament Interspinous ligament Ligamentum flavum Epidural space Dura Arachnoid SA space
Which layers does the needle pass through in an epidural?
Supraspinous ligament
Interspinous ligament
Ligamentum flavum
Epidural space
Path of symoathetic outflow?
Exit with T1-L2 spinal nerves
Travel to symp chains running length of column
Pass into all spinal nerves
How can you tell that a spinal anaesthtic is having its effect?
Lower limbs look flushed
Warm lower limbs
Reduced sweating
Because blockade of sympathetic tone causes vasodilation
Path of pudendal nerve?
Exits pelvis via greater sciatic foramen
Re enters ia lesser sciatic
Travels in pudendal canal
Branches to supply perineum
