Lab Chap 16

Structure	Description	Function
Ventral Median Fissure	A deep groove running along the anterior (ventral) side of the spinal cord.	Divides the spinal cord into left and right halves; important for structure.
Cauda Equina	A bundle of nerve roots at the end of the spinal cord (L2-S5).	Provides nerves to the lower limbs and pelvic organs.
Central Canal	A small canal running through the center of the spinal cord.	Contains cerebrospinal fluid (CSF); part of the ventricular system.
Conus Medullaris	The tapered, lower end of the spinal cord, around the L1-L2 vertebra.	Marks the end of the spinal cord; where the nerve roots of the cauda equina begin.
Dorsal Root	Nerve fibers that carry sensory information to the spinal cord.	Transmits sensory signals from the body to the spinal cord.
Dorsal Root Ganglion	A cluster of sensory nerve cell bodies located on the dorsal root.	Houses cell bodies of sensory neurons; important for sensory signal processing.
Filum Terminale	A delicate fibrous thread extending from the conus medullaris to the coccyx.	Anchors the spinal cord in place, stabilizing it within the vertebral column.
Gray Matter	The inner, butterfly-shaped region of the spinal cord, composed of neuron cell bodies and synapses.	Processes and integrates sensory and motor information.
Lateral Horn	A section of the gray matter found in the thoracic and upper lumbar regions.	Contains autonomic motor neurons, controlling smooth muscle and glands.
Anterior Horn	The front portion of the gray matter, found in all regions of the spinal cord.	Contains motor neurons that control voluntary skeletal muscles.
Posterior Horn	The back portion of the gray matter.	Processes sensory information entering the spinal cord.
Dorsal Median Sulcus	A shallow groove along the posterior (dorsal) side of the spinal cord.	Divides the spinal cord into symmetrical halves; serves as a landmark.
Spinal Nerve	A mixed nerve formed from the joining of dorsal and ventral roots.	Carries both sensory and motor information to and from the spinal cord.
Ventral Root	Nerve fibers that carry motor information away from the spinal cord.	Transmits motor signals from the spinal cord to muscles and glands.
White Matter	The outer region of the spinal cord, composed primarily of myelinated axons.	Transmits nerve impulses up and down the spinal cord to and from the brain.
Lateral Funiculus	One of the three white matter columns on the lateral side of the spinal cord.	Contains ascending and descending tracts that relay sensory and motor information.
Anterior Funiculus	The white matter column on the front side of the spinal cord.	Contains tracts for motor and sensory functions, including autonomic control.
Posterior Funiculus	The white matter column on the back side of the spinal cord.	Carries sensory information to the brain, such as touch and proprioception.
Meninges	Three layers of connective tissue that cover and protect the spinal cord and brain.	Protects and cushions the spinal cord; circulates cerebrospinal fluid.
Dura Mater	The outermost, thick, and tough layer of the meninges.	Provides a protective barrier for the spinal cord.
Arachnoid Mater	The middle layer of the meninges, web-like in structure.	Acts as a cushioning layer, enclosing the cerebrospinal fluid.
Pia Mater	The innermost layer of the meninges, delicate and closely adherent to the spinal cord.	Directly nourishes the spinal cord, contains blood vessels.

Structure	Description	Function
Plexuses	Networks of nerves formed by the merging of spinal nerve roots.	Distribute motor and sensory fibers to specific regions of the body.
Brachial Plexus	A network of nerves formed by the anterior rami of C5-T1.	Supplies motor and sensory fibers to the upper limbs.
Cervical Plexus	A network of nerves formed by the anterior rami of C1-C4.	Supplies motor and sensory fibers to the neck, diaphragm (via phrenic nerve), and parts of the head and shoulders.
Lumbar Plexus	A network of nerves formed by the anterior rami of L1-L4.	Supplies motor and sensory fibers to the lower abdomen, groin, and parts of the legs.
Sacral Plexus	A network of nerves formed by the anterior rami of L4-S4.	Supplies motor and sensory fibers to the buttocks, legs, and pelvic organs.

Here's a study guide chart that organizes the plexuses and nerves with descriptions and functions:

Structure	Description	Function
Plexuses	Networks of nerves formed by the merging of spinal nerve roots.	Distribute motor and sensory fibers to specific regions of the body.
Brachial Plexus	A network of nerves formed by the anterior rami of C5-T1.	Supplies motor and sensory fibers to the upper limbs.
Cervical Plexus	A network of nerves formed by the anterior rami of C1-C4.	Supplies motor and sensory fibers to the neck, diaphragm (via phrenic nerve), and parts of the head and shoulders.
Lumbar Plexus	A network of nerves formed by the anterior rami of L1-L4.	Supplies motor and sensory fibers to the lower abdomen, groin, and parts of the legs.
Sacral Plexus	A network of nerves formed by the anterior rami of L4-S4.	Supplies motor and sensory fibers to the buttocks, legs, and pelvic organs.

Nerve	Description	Function
Axillary Nerve	Arises from the brachial plexus (C5-C6), innervates the deltoid and teres minor muscles.	Motor: Shoulder abduction; Sensory: Skin of the shoulder area.
Femoral Nerve	Arises from the lumbar plexus (L2-L4), innervates the quadriceps and other muscles of the anterior thigh.	Motor: Knee extension; Sensory: Anterior thigh and medial lower leg.
Median Nerve	Arises from the brachial plexus (C5-T1), innervates most of the flexors in the forearm.	Motor: Forearm and hand flexion; Sensory: Skin of the lateral hand and fingers.
Radial Nerve	Arises from the brachial plexus (C5-T1), innervates the muscles of the posterior arm and forearm.	Motor: Elbow, wrist, and finger extension; Sensory: Skin of the posterior arm and forearm.
Sciatic Nerve	Arises from the sacral plexus (L4-S3), the largest nerve in the body, passes through the hip and down the leg.	Motor: Posterior thigh and leg muscles; Sensory: Skin of the foot and leg.
Tibial Nerve	A branch of the sciatic nerve, supplies the posterior leg and foot.	Motor: Plantar flexion and toe movements; Sensory: Skin of the sole of the foot.
Ulnar Nerve	Arises from the brachial plexus (C8-T1), travels along the medial side of the arm and forearm.	Motor: Flexion of the wrist and fingers; Sensory: Skin of the medial hand and fingers.
Phrenic Nerve	Arises from the cervical plexus (C3-C5), travels down to the diaphragm.	Motor: Diaphragm contraction, essential for breathing.