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Parts of the nervous system
• Central nervous system
▫ Spinal cord
▫ Brain Brain stem (medulla oblongata, pons, mesencephalon)
Cerebellum
Diencephalon
Telencephalon
• Peripheral nervous system▫ Spinal nerves▫ Cranial nerves▫ Autonomic nerves
Sympathetic Parasympathetic
© Anne LeRoy 30.9.2015
Neuroglia
• CNS:
▫ oligodendroglia
▫ astrocytes
▫ ependymal cells
▫ microglia
• PNS
▫ satellite cells
▫ Schwann cells
© Anne LeRoy 30.9.2015
Neuron types
• multipolar
▫ motor fibers
▫ autonomic fibers
• pseudounipolar
▫ somatic sensory fibers
• bipolar
▫ retina, ggl of the vestibulocochlear nerve, olfactory epithelium
Multipolar neurons
© Anne LeRoy 30.9.2015
Nervous fiber
• axon
• neurolemma
Schwann cells
▫ producing myelin
▫ not producing myelin
© Anne LeRoy 30.9.2015
Types of fibers
• Afferent = sensory fibersoriginate on receptors in the periphery
▫ somatic sensory fibersexteroceptive and proprioceptive sensations
▫ visceral sensory fibers
• Efferent = motor fibers▫ somatic motor fibers
to skeletal muscles
▫ visceral motor fibersto smooth and cardiac muscles, glands
© Anne LeRoy 30.9.2015
„Nerves“
• nervous fibers
▫ axon
▫ neurolemma (Schwann cells –
producing myelin or not)
• connective tissue
▫ endoneurium, perineurium,
epineurium
• vasa nervorum
© Anne LeRoy 30.9.2015
Ganglia and nuclei
= collection of neuron cell bodies
ganglion: outside the CNS- sensory (DRG)
- autonomic
- sympathetic(tr. sympaticus)
- parasympathetic(periphery)
nucleus: in the CNS
Dorsal root ganglion from a chicken embryo
© Anne LeRoy 30.9.2015
Posterior vs anterior rami
Rami posteriores Rami anteriores
Doesn‘t form plexuses Forms the major somatic plexuses
Both sensory and motor fibers Both sensory and motor fibers
Sensory: skin medially close to thespine
Sensory: skin in the rest of the body
Motor: epaxial muscles Motor: hypaxial muscles
© Anne LeRoy 30.9.2015
Rami posteriores nervorum spinalium
C1: n. suboccipitalism. rectus capitis post. mj.
m. rectus capitis post. mi.
m. obliquus capitis sup.
m. obliquus capitis inf.
C2: n. occipitalis major
C3: n. occipitalis tertius
L1-L3: nn. clunium superiores
S1-S3: nn. clunium medii
© Anne LeRoy 30.9.2015
Rami anteriores
nervorum
spinalium
• Cervical plexus (C2-C4)
• Plexus brachialis (C5-T1)
• rami anteriores nn. thoracicum (T1-T12)
• Pleus lumbalis (T12-L4)
• Plexus sacralis (L4-S1)
• Plexus coccygeus (S5-Co)
© Anne LeRoy 30.9.2015
Plexus cervicalis – sensory branchesPunctum nervosum /Jonáš/
▫ n. occipitalis minor
▫ n. auricularis magnus
▫ n. transversus coli
▫ nn. supraclaviculares
© Anne LeRoy 30.9.2015
Plexus cervicalis – inervated muscles
• mm. scaleni ant. + med. – pl. cervicalis + brachialis
• mm. infrahyoidei – ansa cervicalis prof.
• m. longus colli - pl. cervicalis + brachialis
• m. longus capitis
• m. rectus capitis ant. + lat
• m. sternocleidomastoideus + m. trapezius –ansa Maubraci
© Anne LeRoy 30.9.2015
Plexus cervicalis – n. phrenicus
C3-C5= both sensory and motor
motor: diaphragm
sensory: pleura mediastinalis + diaphragmatica, pericardium, peritoneum parietale (partially), thymus (Cruchet‘s nerve), gallbladder
© Anne LeRoy 30.9.2015
Plexus brachialis
• truncus (trunk)superior (C4+C5+C6)medius (C7)inferior (C8+T1)
• fasciculus (cord)lateralismedialisposterior
• pars supraclavicularis• pars infraclavicularis
© Anne LeRoy 30.9.2015
plexus brachialis –
pars supraclavicularis
• n. dorsalis scapulae
• n. thoracicus longus
• n. subclavius
• n. suprascapularis
▫ incisura scapulae
▫ incisura spinoglenoidalis
• n. thoracodorsalis
© Anne LeRoy 30.9.2015
plexus brachialis –
pars infraclavicularis• fasciculus medialis
▫ n. ulnaris▫ n. cutaneus antebrachii med.▫ n. cutaneus brachii med.▫ n. medianus
• fasciculus lateralis▫ n. musculocutaneus▫ n. medianus
• fasciculus posterior▫ n. axillaris▫ n. radialis
• nn. pectorales• n. subscapularis
© Anne LeRoy 30.9.2015
Entrapment syndromes
= compression of peripheral nerves in anatomical„tunnel“ regions, where they are suceptible to injury.
paresthesia, anesthesia in the area nervina ofthe injuried nerve palsy – according to the motor inervation of
the injuried nerve
Tinel‘s sign
© Anne LeRoy 30.9.2015
n. radialis C5-C8
• sulcus nervi radialis
• behind the head of radius
• canalis supinatorius (r. prof)
▫ Frohse‘s arcade
-> wrist drop
„Saturday night‘s palsy“
© Anne LeRoy 30.9.2015
n. axillaris – C5-C6
• foramen humerotricipitale
-> „flat shoulder deformity“
– increased risk of luxation
© Anne LeRoy 30.9.2015
n. medianus – C5-T1
• ligament of Struthers
• lacertus fibrosus
• canalis pronatorius
• canalis carpi
• -> „preaching hand“
ape hand deformity
• carpal tunnel syndrome
© Anne LeRoy 30.9.2015
Rami anteriores nervorum
thoracicorum
• nn. intercostales I-XI
• n. subcostalis
© Anne LeRoy 30.9.2015
Intercostal nerves – motor branches
• rr. musculares:
▫ mm. intercostales
▫ m.transversus thoracis
▫ m. serratus post.
▫ m. obliquus abdominis ext.
▫ m. obliquus abdominis int.
▫ m. rectus abdominis
▫ m. transvertsus abdominis
▫ m. pyramidalis
nn
. in
terc
ost
ale
s V
II-X
II© Anne LeRoy 30.9.2015
Intercostal nerves – sensory branches
• nn. cutanei laterales
▫ rr. mammarii laterales
▫ nn. intercostobrachiales (IC-II)
• nn. cutanei anteriores (terminal branches of IC I-VI)
▫ rr. mammarii mediales
• rr. pleurales et peritoneales „défense musculaire“
© Anne LeRoy 30.9.2015
Plexus lumbalis T12-L4
• „ I, I Get Laid On Fridays“
• n. Iliohypogastricus – T12-L1
• n. Ilioinguinalis – L1
• n. Genitofemoralis – L1-L2
• n. cutaneus femoris Lateralis – L2-L3
• n. Obturatorius – L2-L4
• n. Femoralis – L2-L4
© Anne LeRoy 30.9.2015
Nerve Motor Sensory Topography
n.Iliohypogastricus
m. Transversus abd.m. Obliquus int. abd.
Sup. to crista iliacaand lig. inguinale
n. Ilioinguinalis m. Transversus abd.m. Obliquus int. abd.
ScrotumLabia majora
Canalis inginalis
n. genitofemoralis
Through m. psoasmajor
r. Genitalis n. genitofemoralis
m. Cremaster ScrotunLabia majora
r. Femoralis n. genitofemoralis
Inf. to lig. inginale Lacuna vasorum
n. Cutaneusfemoris lateralis
Lateral part of thethigh
Lacuna musculorum
n. Femoralis m. IliopsoasAnterior group ofthe thigh
rr. Cutanei ant. femorisn. Saphenus
Lacuna musculorumTrigonum femoraleCanalis adductorius
n. Obturatorius Medial group of thethigh
Medial part of thethigh
Canalis obturatorius
© Anne LeRoy 30.9.2015
Palsies
• n. femoralis
• n. obturatorius: weakened adduction and medial rotation(pregnancy)
• n. cutaneus femoris lateralis: meralgia parestetica
© Anne LeRoy 30.9.2015
Plexus sacralis (L4-S4)
• n. gluteus sup. – L4-S1
• n. gluteus inf. – L5-S2
• n. cutaneus femoris post. – S1-S3
• n. ischiadicus – L4-S3
• n. pudendus – S2-S4
© Anne LeRoy 30.9.2015
n. pudendus• Somatic motor:
▫ pelvic floor▫ perineal muscles
• visceral motor▫ corpora cavernosa▫ corpora spongiosa
• sensory▫ perianal region▫ scrotum/labia majora▫ penis/clitoris
• Topography▫ foramen infrapiriforme▫ foramen ischiadicum minus▫ fossa ischioanalis▫ canalis pudendalis Alcocki
© Anne LeRoy 30.9.2015
Plexus coccygeus S5-Co
• Motor: helps in the inervation of the pelvic floor
• Sensory: nn. anococcygei
(hurts in coccygeal fractures)
© Anne LeRoy 30.9.2015
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