Spinal Nerves Flashcards
Week 1-4 of embryology
1- Fertalization, cleavage, implantation
2- Embryoblast development as a bilaminar embryonic disk
3/4- embryogenic stage with 3 embryonic layers
3 layers of embryo
ectoderm- dorsal-CNS, PNS, epidermis
Mesoderm- middle- Muscle, bone, blood
Endoderm- ventral- gut tube and glands
Neuromere
-elevation in the wall of neural tube where a pair of dorsal + ventral nerves attach
Somite
One of the paired cell masses formed in the pariaxial mesoderm next to the neural tube
myotome
mesenchymal cells of a somite to for a band of skin innervated by 1 spinal nerve
Dermatome
Mesenchymal cells of a somite to form a band of skin innervated by 1 spinal nerve
What level does the spinal cord end
l1/2
at what level of vertebra protects each portion of the spinal cord
Upper cervical- same bony level Lower cervical- 1 bony level above Upper thoracic- 2 bony levels lower thoracic- 3 bony levels lumbar- t10/11 sacral- T12/l1 Coccygeal- L1/2
Dorsal root function
Sensory
Ventral root function
Motor
Trunk of the spinal nerve is formed by
unionn of the dorsal and ventral roots
mixed function- sensory +motor
C1 nerve is predominatly (function)
Motor
What PPR supply the skin AND the intrinsic back muscles
Medial PPR C2-T6
Lateral PPR T7-S3
What PPR supply ONLY the intrinsic back muscles
Lateral PPR C2-T6
Medial PPR T7-S3
APR function
Mixed nerve; innervation of the skin and muscles of the neck, antero lateral trunk, upper and lower limbs
White rami connections level, origin, projection
T1 (c8)- L2(L3)
origin- spinal sympateic center
Paravertebral sympatheic ganglion
Gray rami connections, level, origin, projection
All levels
Origin- paravertebral sympathetic ganglion
Projection- axon bundles merge into the APR and PPR to innervate the glands of the skin, blood vessels of skin and arrector pilli muscles
Sinuvertebral nerve
After emerging from spinal nerve outside the IVF it looks backwards to the vertebral canal
-innervates dural mater + sleeves
The dermatomal contribution to the back is given by the
PPR
What is the blood supply of Cervical, Thoracic, Lumbar, Sacral
Cervial- Vertebral A (ascending, deep cervical)
Thoracic- (1-11 post intercostal arteries)
Lumbar- (1st-5th lumbar artery)
Sacral- ( Lateral, Medial sacral)
Spinal Ramus- Origin, course, branches (and what they supply)
Origin- Segmental artery
Course- IVF towards vertebral canal
Branches- Spinal nerve will go into canal and split into two radicular arteries
ant. radicular- supplies ventral root of SN
Post. radicular- supplies dorsal root of SN
Artery that supplies the lumbosacral enlargement
Adamkiewicz
