Exam 2 Flashcards
Nerve plexuses
At spinal cord levels, except for T2-T12, the anterior rami converge and diverge from each other forming these web-like plexuses. These fibers of the anterior rami intermingle and are redistributed
Why do &2-T12 not have nerve plexuses
Bc these nerves are mainly distributed exclusively to the truck
What are mutlisegmental peripheral nerve
A nerve that arises from the plexus that also conveys fibers to all or parts of other adjacent dermatomes
What arises from the nerve plexus
-Each anterior ramus contributes fibers to multiple peripheral nerves via the nerve plexuses , each of these peripheral nerve contain fibers from multiple spinal nerves
Two types of fibers
- the fibers carried by spinal nerves - segmental innervation (get dermatomes)
-fibers carried via branches of a plexus (mutlisegmental nerves)
Visceral sensory fibers (reflex and pain)
- Both visceral reflex senstations and pain impulses travel on on viseceral afferent fibers and travel info in opposite directions as the mother fiber they accompany
-reflex accompanies parasympathetic while pain is sympathetic
Visceral autonomic motor fibers
-organized into sympathetic and parasympathetic division; bth involve a 2-neuron chain btwn CNS & effector cell
-Pre & post synaptic neurons
Pre & post synaptic neurons
- pre = preganglionic have cell bodies w/in CNS gray matter and stretch out to autonomic ganglia
-post = postganglionic wh/ have cell bodies w/in autonomic ganglia & stretch out to smooth, Cardiac or gland cells
Sympathetic nervous system - division
Splits into paraveterbral ganglia or prevertebral ganglia
Paravertebral ganglia
Linked to form right and left sympathetic trunks (all motor) on each side of the vertebral column.
Prevertebral ganglia
Are in the plexuses that surround the origins of the main branches of the abdominal aorta
Celiac ganglia
-is a prevertebral ganglia that surrounds the origin of the celiac trunk
Superior cervical ganglion
- A paravertbral ganglia AKA superior paravertebral ganglion wh/ lies at the base of the cranium (1 per each of the sympathetic trunk)
Ganglion impar
-is an unpaired paravertebral ganglia that forms inferiorly where the 2 sympathetic trunks unite at the level of the coccyx
Sympathetic nervous system route (pregranglionic)
Preganglionic neurons leave the spinal cord thru anterior roots (bc they are motor fibers) & enter the anterior rami. Almost immediately after all preganglionic fibers leave the anterior rami of these spinal nerves & pass to the sympathetic trunk thru white rami communicates. Within the the sympathetic truck their are 3 possible courses
What are the three possible courses
- Synapse immediately w/ a postganglionic nervous of the paravertebral ganglion at the same level
- Ascend or descend in the sympathetic trunk to synapse w/ a postganglionic neuron of a higher or lower paravertebral ganglion
- Pass thru the sympathetic trunk w/o synapsing, continuing thru an adominopelvic splanchnic nerve to reach & synapse w/in a prevertebral ganglion
Sympathetic NS (postganglionic neurons)
Postganglionic fibers destined to reach structures of the neck, body wall, and limbs pass from the paravertebral ganglia thru grey rami communicantes & into both the anterior rami and the posterior rami of all 31 pairs of the spinal nerves
Splanchnic nerves of the postganglionic neurons
Convey visceral motor fibers to the visceral of the body cavities, these nerves also carry visceral sensory fibers from the same visceral towards the CNS
Sympathetic fibers destined for the viscera of the thoracic cavity
Pass thru cardiopulmonary splanchnic nerves to enter the cardiac, pulmonary, & esophageal pleaxyses, these fibers are postganglionic
Sympathetic fibers that are innervation of viscera of the abdominopelvic cavity
They pass thru the abdominopelvic splanchnic nerves, including the greater splanchnic, lesser splanchnic, least splanchnic & lumbar splanchnic nerves. These fibers are preganglionic and postganglionic fibers exiting prevertebral ganglia
Parasympathetic NS division
Fibers of preganglionic parasympathetic motor neurons exit the CNS
-W/in CN III, VII, IX, & X these neurons have cell bodies w/in brainsteam
-thru anterior roots of sacral spinal nerves S2-4, these neurons have cell bodies in the sacral segments of the spinal cord at levels S2-S4
Pelvic splanchnic nerves
Carry preganglionic parasympathetic fibers, arise from rami of spinal nerves S2-4 & innverate pelvic visceral plus the descending colon
Structures that innervated via parasympathetic NS
Sacral (descending colon & down)& cranial (head, Ascending & transverse colon) parasympathetic outflow wh/ innervates: strucures of the head, thoracic, abdominopelvic cavities, & erectile tissues of clit & penis.
*W/ expection of the penis & clit. The parasympathetic NS Doesn’t reach the body wall or limbs
What are the pairs of synapse-containing parasympathetic ganglia that occur in the head?
-Ciliary ganglion
-Pterygopalatine ganglion
-Submandibular ganglion
-Otic ganglion
Intrinsic or enteric ganglion
-They are preganglionic fibers synapse w/ postganglionic cell bodies that occur in or on the walls of the target organs
Enteric NS
-Contains Sensory & motor neurons
-includes two interconnected plexuses w/in the walls of the GI tract (myenteric plexus & submucosal plexus)
-The motor neurons receive input form the CNS via autonomic pathways. They synapse on & regulate activity of: smooth musicale contractions, exocrine glandular secretions, & endocrine secretions of the GI tract wall
Somatic sensory
Somatic motor
Visceral sensory
Visceral motor (symp & parasymp)
Are from or go to:
-from skin
-to skeletal muscle
-from viscera
-to viscera (smooth muscle, cardiac, glands)
Functions of the vertebral column
-protects the spinal cord & SN
-Supports the weight of the body superior to the level of the pelvis
-provides a partly rigid yet flexible axis for the body & a base on which the head is placed & pivots
-plays an important role in posture & locomotion
Adult vertebral column is arranged in 5 regions
7 cervical
12 thoracic
5 lumbar & sacral
4 coccygeal
The sacrum & coccyx formation
-the 5 sacral fuse in the adult to for the sarcum & after the age of 30 the 4 coccygeal fuse to form the coccyx
Intervertebral (IV) disc
The joints where adjacent vertebrae meet
*No IV disc btwn C1 &2
Zygapophysial joints
-where the two articular process of two vertebra (inferior process of one and superior process of another vertbrea) meet
Body (vertebral body)
Vertebral arch
-supports weight
- consist of 2 Pericles (R & L) and 2 laminae (R & L)
DRAW
Vertebral foramen
Vertebral canal
Intervertebral foramen
-formed by the vertebral arch + part of the body &b protects the spinal cord
-formed by all vertebral foramina in the articulated column stacked together, contains the spinal cord, roots of the spinal nerves, membranes, fat & vessels (goes superior to inferior)
-hole btwn 2 adjacent vertebra, spinal nerves emerge from the vertebral column thru these holes (goes lateral to medial)
What are the 7 processes of the vertebra
-spinous process- projects posteriorly (us. Inferiorly), functions in muscle attachment & movement. (Single & median)
-transverse process(s)- projects laterally; functions in muscle attachment & movement (R & L)
-Superior articular processes (2) & inferior articular processes (2) - each bears a cartilage-covered articular facet * all have R & L
What do the articular processes do?
-they (Inf & sup of 2 vertebra ) form the zygapophysial joints
-determine the type of movement allowed and not allowed between adjacent vertebra of each region
-keep adjacent vertebrae aligned
Cervical vertebrae
-Have a foramen transversarium (transverse foramen) wh/ is a hole in the transverse process (not C7) allows passage of the vertebral artery & accompanying vein
-Spinous process may be bifid (notched)
Atlas
-C1
-has neither a body nor spinous process
-Has paired superior articular surfaces Wh/ articulate/aline with the occipital condyle of the skull
-Transverse ligament of atlas holds their dens of the axis against the anterior part of the atlas
Axis
-C2
-has a tooth-like density which projects superior from its body, C1 wh/ carries the cranium rotates on C2
Vertebra prominens
-C7, has a particularly long spinous process, allowing you to fill it at the base of your neck
Thoracic Vertebrae
-Ribs join all 12 of these, thus they all posses smooth, cartilage-covered costal facets ( 2 on each side of the body, 1 on each transverse process)
The costal facet on the vertebra’s transverse process makes a joint with:
The costal facet on the vertebra’s body makes a joint with:
-a rib tubercle
-a rib head
*In most locations it takes facets from two adjacent vertebral bodies to receive a single rib head
Epidural space
-separates the spinal dura mater, to which it’s superficial from the periosteum-covered bone & ligaments that form the walls of vertebral canal-> contain fat
Lumbar vertebrae
-Have large bodies & posses neither foramina transversaria nor costal. Facets
-Spinous processes are square-ish and mostly don’t slope inferiorly
-L5 carries the weight of the complete upper bodyt which transmits to the base of the sarcum
Sacrum
Usually composed of five fused sacral vertebrae in adults
-located btwn & articulates with the hip bones
-provides strength & stability to pelvis & transmits the weight of the body to the pelvic girdle
-inferior half not weight bearing
Sacral canal
-continuation in the sacrum of the vertebral canal, contains bundle of SN roots = cauda equina
Base of sacrum
Formed by the superior surfaces of the S1 vertebra
Apex of the sacrum
-formed by the inferior surface of S5
Sacral promontory
-the anterior projecting edge of the body of s1 vertebra- base
Median sacral crest
-the fused rudimentary spinous processes of the superior three or four sacral vertebrae
Sacral hiatus
-an inverted U due to the absence of spinous processes of S5 and sometimes S4, leads into sacral canal
Anterior sacral foramina & posterior sacral foramina
-pairs of holes for the exit of the anterior and posterior rami, respectively of the SN, both communicate with the sacral canal
Why is the sarcum titled
So that it can articulate with the L5 vertebra at the lumbosacral angle which can vary from 130 to 160
Coccyx
-tailbone
-formed by fusion of 3-5 rudimentary coccygeal vertebrae, provides attachments for a few muscles
Intervertebral disc
-btwn the bodies of adjacent vertebrae; annulus fibrosus + nucleus pulposus
Annulus fibrosus
-a bulging fibrous ring consisting of concentric layers of fibrocartilage (outside; goes around nucleus pulposus)
Nucleus pulposus
-semifulid, gelatinous core of the disc
What is the anterior longitudinal ligament
-connects the antihero aspects of the vertebral bodies & IV discs it extends from the sacrum to C1 & the skull & resists hyper extension
What is a herniated disc?
You get a protrusions of the nucleus pulposus into or thru the annulus fibrosus
*a well recognized cause of lower back pain and low limb pain
Zygapophysial joints
-btwn an inferior articular process & the superior articular process of the next most inferior vertebra
Ligaments flava
Extend almost vertically from the laminate above to the laminate of the next vertebra below, they resist separation of the vertebral laminate by limiting flexion of the column, prevents injury of IV disc
Nuchal ligament
-from skull to the spinous processes of vertebrae; provides attachment for muscles
Atlanta-occipital joints
-paired synovial joints btwn C1 superior articular sufaces & the occipital bone of the skull, permit the yes flexion
Atlanta-axial joints
- 3 synovial joints btwn c1 & 2 which allows the rotation of the head when one shakes “no”
-R&L lateral and a single median Atlanto-axial joint
Primary curvatures
Develop during fetal period & are retained thruout life, are concave anteriorly
-thoracic kyphosis & sacral kyphosis
Secondary curvatures
-develop during infancy & childhood, they are concave posteriorly
-cervical & lumbar lordosis
Excessive thoracic kyphosis
-an abnormal increases in the thoracic curvature (hunchback)
Excessive lumbar lordosis
-an abnormal increase in the lumbar curvature
Scoliosis
-an abnormal lateral curvature
Segmental arteries
Such as lumbar arteries supply blood to the vertebral column
Internal & external vertebral venous plexuses
-collect blood from the vertebrae & drain into larger veins that lead back to the heart
Splenius Capitis
O, I, innervation, action
-from nuchal ligament & spinous processes of vertebrae
-temporal & occipital bones of the skull
-posterior rami of the SN
-extend head & neck; laterally flex neck and rotate head
Splenius cervicis
O,I, innervation, A
-from nuchal lig & spinous processes of vertebrae
-transverse processes of cervical vertebrae
-posterior rami of SN
-extend head & neck; laterally flex neck and rotate head
Erector spinae
-main extensor of the vertebral column, 3 parts
Iliocostalis
O,I, innervation, A
-from hipbone, sacrum, & spinous processes of lumbar vertebrae
-lower ribs & cervial transverse process
-posterior rami of SN
-extend vertebral column
Longissimus
O,I, innervation, a
-from hipbone, sacrum & spinous processes of lumbar vertebrae
-tor it’s, transverse processes of thoracic and cervical vertebrae & skull
-posterior rami of SN
-extend vertebral column
Spinalis
-O,I, innervation, a
-spinous process of lumbar vertebra
-spinous process of thoracic vertebrae
-posterior rami of SN
-extend vertebral column
Transversospinalis
-semispinalis
-multifidus
-rotatores
Semispinalis, multifidus, retatores O,I,A
-transverse processes of vertebrae
-spinous processes of more superior vertebrae
-extend vertebral column
Thoracolumbar fascia
-deep fascia which extends laterally from the spinous processes of vertebrae & forms a thin covering over the deep or intrinsic back muscles. * all three layers of muscles