spinal cord

81問 • 2年前

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is a cylindrical cord inside the spinal cavity which is about as thick as a pencil.

spinal cord

extends from the foramen magnum of the skull downward (caudally) for about 45 cm (18 inches) to the level of the first lumbar vertebra (L1) in adults.

spinal cord

The upper end of the organ is continuous with the lowermost part of the brain (

medulla oblongata

Its lower end tapers off as the cone-shaped which is located in the vicinity of the first lumbar vertebra

conus terminalis or conus medullaris

Extending caudally from the conus is a non-neural fiber called the

filum terminale

filum terminale is attached at?

coccyx

filum consists of??

fibrous connective tissue

It is slightly flattened dorsally and ventrally with two prominent enlargements known as

cervical and lumbosacral

Emerging from these enlargements are

spinal nerves

spinal cord is divided into how many segments

31 segments

Each pair typically passes through a pair of

invertebral foramen

cervical

thoracic

lumbar and sacral

coccygeal

The roots of all nerves pass caudally below the conus terminalis (below L1 vertebral level) resemble flowing coarse strands of hair. For this reason, the lumbar and sacral roots are collectively called the

cauda equine

The spinal cord and the roots of its nerves are protected not only by the

flexible bony vertebral column and its ligaments

is a tough, fibrous membrane that emerges with the filum terminale;

dura mater

a delicate and transparent membrane which runs caudally to the S2 vertebral level, where it joins the filum terminale

arachnoid membrane

thin highly vascular which is tightly attached to the spinal cord and its roots

pia mater

Cross-sectionally, the spinal cord has a tiny___.containing ____ and a dark portion of H-shaped or butterfly-shaped "gray matter

central canal cerebrospinal fluid

It is divided into more or less symmetrical left and right halves by a deep groove called the

anterior median fissure and posterior median septum

Extending out from the spinal cord are the

ventral and dorsal roots

H-shaped gray matter of the spinal cord has two pairs of columns that form the two vertical bars of the H which are called the

horns

The pairs that form the cross bars of the H is knows as___ which functions in cross reflexes.

gray commissure

which run dorsally and function in afferent input;

posterior horns

which run ventrally and function in efferent somatic output

anterior horns

At each segment of the spinal cord, a pair of nerves branches and exits the

h shaped gray matter

One nerve of the pair exits to the left, entering the

left side of the nody

Each nerve has a ventral (anterior) and a dorsal (posterior) root which meet shortly after leaving the spinal cord to form a

single mixed nerve

spinal nerves are named for their

associated vertebra and number

The numbering of each of the spinal nerve other than the cervical nerves corresponds to the

vertebra above

A short distance after the dorsal and ventral roots join together to form a

spinal nerve proper

the nerve divides into several branches called

rami

what branch of ramus innervate the skin of the back, the skin on the back of the head, and the tissues and intrinsic (deep) muscles of the back.

branches of the dorsal ramus

a ramus innervate the skin tissues, and muscles of the neck, chest, abdominal wall, both pairs of the limbs, and the pelvic area.

branches of the ventral ramus (

innervates the vertebrae, spinal meninges, and spinal blood vessels

meningeal ramus

are composed of sensory (general visceral afferent) and motor nerve fibers associated with the autonomic nervous system innervating the visceral structure

rami communicantes (ramus communicans)

complex networks of nerves formed by the ventral rami of the spinal nerves (except T2 through T12

plexuses

complex networks of nerves formed by the ventral rami of the spinal nerves (except T2 through T12

plexuses

composed of the ventral rami of the spinal nerves C1 through C4. Its branches supply the muscles, skin of the neck, and posterior part of the scalp.

cervical plexus

is the most important branch of the cervical plexus is formed by the rami of C3, C4 and C5 These nerves descend into the thorax to innervate the diaphragm

phrenic nerve

is made up primarily of the ventral rami of C5 to C8 and T1 spinal nerves. This extends downward and laterally, passing behind the clavicle and into the armpit. This plexus give rise to five major nerves that supply a number of neck and shoulder muscles in addition to the entire upper extremity

brachial plexus

supplies the anterior arm muscles (biceps brachii) and the skin of the lateral forearm

musculocutaneous branch

supplies the deltoid muscle and the skin over the deltoid muscle

axillary branch

supplies the flexor muscles in the anterolateral aspect of the forearm and the hand and the skin in the radial half of the palm

Median branch

supplies the flexor muscles in the anteromedial aspect of the forearm and the hand and the skin of the same region

ulnar branch

is the largest branch of the brachial plexus and supplies the muscle and skin of the posterior aspect of the arm. forearm and hand

radial branch

composed of fibers of the ventral rami of L1 to L4 nerves. Supplies the motor and sensory fibers to the anterior and lateral abdominal wall, external genitals and the thigh

lumbar branch

is the largest branch of the plexus and innervates the iliopsoas and the quadriceps femoris muscles and the skin on the anteromedial aspect of thigh, and

femoral branch

innervates the adductor muscles of thigh and the skin

obturator nerve

is composed of fibers of the ventral rami of L4, L5, S1 through S3 spinal nerves. Its branches supply the structures in the buttocks, the perineum and the lower extremity.

sacral plexus

the thickest and longest nerve in the body which extends from the pelvic area to the foot and dividing above the knee into the common peroneal and tibial nerves. This nerve supplies the gluteus maximus and the hamstring muscles.

sciatic nerve

nerve supplies the posterior calf muscles

tibial nerve

supplies the lateral and anterior muscles of the leg

common peroneal nerve

innervates the gluteus medius and gluteus minimus, and tensor fascia lata muscles

Superior gluteal nerve

innervates the gluteus maximus muscle

Inferior gluteal nerve

innervates the voluntary muscles of the perineum, especially the sphincters of the urethra and anus.

pudendal nerve

formed by the coccygeal nerve (Co1) and sacral nerves S4 and S5. A few nerve filaments supply the skin in the cоссух region.

Coccygeal plexus

are the second through twelfth thoracic nerves (T2 to T12). The ventral of the intercostal nerves innervate muscles and skin in the thoracic and abdominal walls.

intercostal nerve

innervate the intercostalmuscles and the abdominal wall and its overlying skin.

Nerves T7 through T12

innervate intercostal muscles and the skin on the lateral and anterior thoracic walls.

T2 through T6

both sensory and motor fibers that together with the cranial nerves form the

peripheral nervous system

cervical plexus participating

c1-c4

brachial plexus participating

c5 to c8

lumbar plexus participating

l1 to l4

sacral plexus participating

l4,l5 and s1

coccygeal participatint

s4 and s5

innervates deltoid

axillary branch

innvervates diaphragm

phrenic nerve

Hamstring muscles

sciatic nerve

biceps brachii

musculocutaneos nerve

coracobrachialis

musculocutaneos nerve

quadriceps femoris muscles

femoral nerve

gastrocnemius

tibial nerve

triceps brachii

radial nerve

external intercostals

thoracic spinal nerve

gluteus maximus

inferior gluteal nerve

two nerve in sacral

tibial and common peroneal nerve

involve a series of responses to receptors in the skin and muscles. - These reflexes help us to move and maintain a correct posture.

somatic spinal reflex

occur in certain organs, for example, when the urinary bladder becomes distended and evokes the urge to urinate. - these reflexes also help to regulate blood pressure by affecting the smooth muscle in blood vessels, and also influence the action of glands.

Visceral spinal reflexes

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Conan Clint · 100問 · 2年前

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