0Horner's Syndrome:-
Sympathetic Innervation:
Sympathetic nerves of upper limb are derived from spinal segments T2 to T6.
Lateral Horn Cells
⇓
Preganglionic fibres
⇓
Ventral Nerve Root
⇓
White rami communicantes
⇓
Sympathetic chain
⇓
ascend within the chain
⇓
end in Middle, Inferior cervical ganglions & first thoracic ganglion
⇓
Postganglionic fibres
↓
From Middle Cervical From Inferior First thoracic Ganglion
ganglion Cervical ganglion
⇓ ⇓ ⇓
Grey rami Grey rami Grey rami
communicantes communicantes communicantes
⇓ ⇓ ⇓
C5, C6 nerve roots C7, C8 nerve roots T1 nerve root
Sympathetic actions - Vasodilation of arteries of Skeletal muscles.
In the Skin - Vasomotor - constricts the arterioles
Sudomotor - increases sweat secretion
Pilomotor - contracts Arrector pilorum muscle causes erection of hair.
If T1 is injured proximal to white rami communicans to first thoracic sympathetic ganglion,
there will be
- ptosis
- miosis
- anhydrois
- enophthalmus
- loss of cilio-spinal reflex.
This is because of injury to sympathetic fibres to head and neck that leave the spinal cord through nerve T1.
Vasomotor changes: skin area with sensory loss is - warmer due to arteriolar dilation.
- drier due to absence of sweating.
Trophic changes: long standing case of paralysis leads to dry and scaly skin. Nails crack easily with atrophy of pulp of fingers.
