GENERAL HISTOLOGY

Detailed explanation-1: -The cervical and lumbosacral segments have a large ventral gray horn for the brachial and lumbosacral plexus-these plexus supply the upper and lower limb extremities.

Detailed explanation-2: -Two enlargements of the spinal cord can be visualized: The cervical enlargement, which extends between C3 to T1; and the lumbar enlargements which extends between L1 to S2 (Figure 3.1). The cord is segmentally organized. There are 31 segments, defined by 31 pairs of nerves exiting the cord.

Detailed explanation-3: -The cervical enlargement of the spinal cord is the source of the spinal nerves that contribute to the brachial plexus and supply the upper limbs.

Detailed explanation-4: -The cervical and lumbar regions of the spinal cord show a larger diameter compared to the rest of the regions. The cervical enlargement and lumbar enlargement represent an increased amount of neurons in the gray matter and axons in the white matter that serve the upper limbs and lower limbs, respectively.

Detailed explanation-5: -Roots C5, C6, and C7 produce the long thoracic nerve, responsible for controlling the serratus anterior.