Clinically Relevant Anatomy of the Spinal Nerves

The first dorsal webspace of the foot is innervated by the deep fibular nerve superficial fibular nerve( deep fibular nerve, superficial fibular nerve ) and exists as the L5 L4 S1 S2( L5, L4, S1, S2 ) dermatome

The postcentral gyrus is also known as the primary somatosensory cortex primary motor cortex( primary somatosensory cortex, primary motor cortex )
The precentral gyrus is also known as the primary motor cortex primary somatosensory cortex( primary motor cortex, primary somatosensory cortex )

The Musculocutaneous nerve supplies the Biceps Brachii Triceps Brachii( Biceps Brachii, Triceps Brachii ) and originates from the C5 and C6 C4 and C5 C6 and C7 C7 and C8( C5 and C6, C4 and C5, C6 and C7, C7 and C8 ) spinal nerves.

Posteriorly, the neck and scalp skin is mainly supplied by the posterior anterior( posterior, anterior ) rami of spinal nerves C2 C1 C3( C2, C1, C3 )-C8

Clinical Testing of Spinal Reflexes:
Biceps Reflex tests C5 & C6 C6 & C7 C4 & C5( C5 & C6, C6 & C7, C4 & C5 ) spinal nerves
Triceps Reflex tests C7 C6 C8( C7, C6, C8 ) spinal nerve
Knee Jerk Reflex tests L3 L2 L1( L3, L2, L1 ) spinal nerve
Ankle Jerk reflex tests S1 S2 S3( S1, S2, S3 ) spinal nerve