structure and spinal chord

Posterior Median Sulcus

Location: Shallow groove on the midline of the posterior (dorsal) side of the spinal cord.

Function: Separates the left and right halves of the spinal cord dorsally.

Anterior Median Fissure

Location: Deep groove on the midline of the anterior (ventral) side of the spinal cord.

Function: Separates the left and right halves of the spinal cord ventrally.

Arachnoid Mater

Location: Middle layer of the meninges, between dura mater and pia mater.

Function: Contains cerebrospinal fluid (CSF) in the subarachnoid space to protect the spinal cord.

Dura Mater

Location: Outermost meningeal layer, tough and protective.

Function: Provides structural support and protection to the spinal cord.

Pia Mater

Location: Innermost meningeal layer, directly covering the spinal cord.

Function: Supplies nutrients and oxygen, helps maintain spinal cord shape.

Dorsal Root Ganglion

Location: Swelling on the dorsal root, outside the spinal cord.

Function: Contains sensory neuron cell bodies that transmit signals to the spinal cord.

Dorsal Root

Location: Extends from the posterior side of the spinal cord, connects to dorsal root ganglion.

Function: Carries sensory (afferent) information into the spinal cord.

Dorsal Ramus

Location: Branches from the spinal nerve, extending posteriorly.

Function: Carries sensory and motor fibers to the back muscles and skin.

Ventral Root

Location: Extends from the anterior side of the spinal cord, joins the dorsal root.

Function: Carries motor (efferent) signals from the spinal cord to muscles/glands.

Ventral Ramus

Location: Larger branch extending anteriorly and laterally from the spinal nerve.

Function: Carries sensory and motor signals to the front of the body and limbs.

Spinal Nerve

Location: Formed where dorsal and ventral roots merge, just outside the spinal cord.

Function: Contains both sensory (afferent) and motor (efferent) neurons.

White Matter of Spinal Cord

Location: Outer part of the spinal cord, surrounding gray matter.

Function: Contains myelinated axons, forming ascending (sensory) and descending (motor) tracts for communication.

Gray Matter of Spinal Cord

Location: Central "butterfly-shaped" region of the spinal cord.

Function: Contains neuron cell bodies, dendrites, and synapses, processes sensory and motor information.

cervical region spinal nerves

Number of Spinal Nerves: 8 pairs (C1-C8)

Notes: Even though there are only 7 cervical vertebrae, there is an extra nerve (C8) that exits below C7.

thoracic region spinal nerves

Number of Spinal Nerves: 12 pairs (T1-T12)

Notes: These nerves primarily control the chest, abdominal muscles, and some back muscles.

lumbar region spinal nerves

Number of Spinal Nerves: 5 pairs (L1-L5)

Notes: These nerves control lower limb movements and sensation.

Sacral Region

Number of Spinal Nerves: 5 pairs (S1-S5)

Notes: These nerves contribute to the sciatic nerve and control pelvic organs & leg muscles.

Coccygeal Region

Number of Spinal Nerves: 1 pair (Co1)

Notes: The smallest nerve, contributing to sensory function in the pelvic area.

Posterior (Dorsal) Horn (gray matter of spinal chord)

Function: Processes sensory (afferent) input from dorsal root ganglion.

Info Type: Touch, pain, temperature, and proprioception from the body.

Anterior (Ventral) Horn

Function: Contains motor (efferent) neurons that send signals to skeletal muscles.

Info Type: Voluntary motor control of muscles.Lateral Horn (Only in thoracic & upper lumbar regions)

Lateral Horn (Only in thoracic & upper lumbar regions) (gray matter of spinal chord)

Function: Contains visceral motor neurons of the autonomic nervous system (ANS).

Info Type: Sympathetic nervous system control (involuntary functions like heart rate & digestion).