Human anatamy

Ⅱ）Branches

1. Femoral n.

Descending between psoas major and iliacus m. deep to inguinal ligament muscular spacefemoral trigone in front side of thigh

pectineus m.

Muscular branches quadriceps femoris m.

sartorius m.

skin of anterior surface of thigh and knee joint.

Cutaneous branches

saphenous n.-medial side of leg and foot.

2. Obturator n.

Medial border of psoas major m. along lateral pelvic wall through obturator

through obturator canal

canal-----------------------------------------medial part of thigh.

Muscular branchesm. of medial group of thigh

Cutaneous branchesskin of medial sie of thigh

Ⅴ. The Sacral Plexus

Ⅰ）Formation

It is formed by lumbosacral trunk (L₄, ₅), the ventral rami of sacral n. (S₁, ₅) and coccygeal n. (C₀). It is tocated in front of sacrum and piriformis m., and behind internal iliac a.

Ⅱ）Branches

1. Superior gluteal n.

It leaves the pelvis via the greater sciatic foramen above the piriformis m.and supplies the gluteus medius m., glutecus minimus m., and tensor fasciae latae m.

2. Inferior gluteal n.

It leaves the pelvis through the greaer sclatic foramen below the piriformis m. and distributes the gluteus maximus m.

3. Pudendal n.

Greater sciatic foramen inferior to piriformis m. winding round ischial

lesser sciatic foramen

spine------------------------------------ischiorectal fossainnervating m. and skin of the perineum and external genital organs.

Its branches perineal n.

4. Sciatic n.

It is largest nerve in the body.

Leaving pelvis through greater sciatic foramen below piriformis m. deep to gluteus maximus m. between ischial tuberosity and greater trochanter of femurposterior compartment of thighdeep to biceps femoris m. uperior angle of popliteal fossatibial n. and common peroneal n.

The trunk of sciatic n. supplies the muscles of posterior group of thigh.

1）Tibial n.

Descending in popliteal fossadescending and supplying muscles of posterior group of

medial planter n.

legbehind medial malleolusplantar lateral planter n. skin and m. in dorsum of foot.

2）Common peroneal n.

Descending along medial border of biceps femoris m. winding aroud fibular neck tofront side of leg

peroneus longus and brevis m.

Superficial peroneal n. ---- skin of lateral side of leg, dorsum

of fot and toes.

---------

Deep peroneal n. ---------- of foot

skin between the first and second toes.

In summary, the common peroneal n. supplies the muscles of anterior and lateral group of leg, and the skin on lateral side of leg, dorsum of foot and toes.

Section 2 The Cranial Nerves

There are twelve pairs of cranial nerves attach to brain , which leave or enter the skull through a series of foramina in the base of the cranium.They are listed as follows by Roman numerals.

They components of cranial n. are more complex than tha of spinal n., the former consists of seven kinds of fibres.

Special somatic sensory fibres

Sensory fibres General visceral sensory fibres

Special visceral sensory fibres

Motor fibres General visceral motor fibres

Special visceral motor fibres

Ⅰ. Olfactory Nerve (CN I)

It is a sensory n. and serves the smell sense.

Central processes of olfactory cells in mucous membrance of upper parts of superior nasal

cribriform plate

concha and nasal septumolfactory fibres-------------------------------------olfactory bulb.

Ⅱ. Optic Nerve (CN Ⅱ)

It is composed by special somatic sensory fibres conducting visual stimulation.

optic disc optic canal

Ganglion cells of retina-------------piercing scleraoptic n. ------------------middle cranial fossaoptic chiasma, optic tractdiencephalon.

Ⅲ. Oculomotor Nerve(CN Ⅲ)

somatic motor n.- oculomotornucleus

Motor n. ---------------

visceral motor n.-accessory oculomotor nucleus

(Edinger-Westphal nucleus)

interpeduncular fassa

oculomotor n. -------------------------------------leaving skull---------lateral wall of cavernous

superior orbital fissure

sinus---------------------------------------------------------------orbtial cavity

-------------------- levator palpebrae superioris m.

inferior retus m.

inferior ramus medial retus m.

inferior oblique m.

A short branch given off by the n. for inferior oblique m. (parasymatthetic n.) ciliary

sphincter m. of pupil (iris)

ganglion (relay) sphincter m. of pupil (relay) ----

ciliary m.

reflex of light(pupil)

-------

regulating convexity of lens

This is the smallest cranial nerve.

Leaving skull below inferior colliculus of midbraincurving around lateral surface of cerebral pedunclelateral wall of cavernous sinusuperior orbital fissureorbitsupplying superior oblique m.

Ⅴ. Trigeminal Nerve(CN Ⅴ)

This is the largest one of cranial nerve and a mixed nerve containing somatic sensory and special visceral fibres.

Motor, pontil, spinal tract, mesencephatic nuclcus of trigeminal n.

larger sensory root ophthalmic n.

 trigeminal n. maxillary n.

smaller motor root mandibular n.

Sensory fibres: skin of face (divided by mouth slit, palpebral fisure); mucousmembrance, ---- of oral cavity,nasal cavity,paranasal sinus;teeth, brain meninges.

Motor fibres: m. of mastication, mylhyoid m. anterior belly of digastric m.

Trigeminal ganglion is a sensory ganglion situated in anterior surface of apex of petrous part of temporal bones.

Ⅰ）Ophthalmic Nerve

It is a sensory nerve.

Trigeminal ganglionophthalmic n. lateral wall of cavernous sinussuperior orbital fissureorbit.

1. Lacrimal n.

This nerve supplies the lacrimal gland and the upper eyelid.

2. Frontal n.

It has 2～3 branches , in which the supraorbital nerve passes through the supraorbital notch (or foramen) to the skin of the frontal area.

3. Nasociliary Nerve

It supplies the nasal mucous membrane, ethmoidal sinuses, lacrimal sac, the skin of dorsal surface of the nose, eyeball, and eyelid.

Ⅱ）Maxillary Nerve

It is a sensory nerve.

Trigeminal ganglion----maxillary n. ---------lateral wall of cavernous sinus-------round

foramen-------inferior orbital fissure---------------infraorbital n.

1. Infraorbital n.

Maxillary n. orbitinfraorbital groove, canal, foramenskin of lower eyelid, nose, and upper lip.

2. Zygomatic n.

It supplies the skin of the temporal and zygomatic area of face.

Parasymapathetic postganglionic fibres from facial n. zygomatic n. communicating branchlacrimal n. lacrimal gland.

3. Supperior alveolar n.

Anterior, middle, posterior branchessuperior dental plexusmaxillary sinus, upper teeth and gums.

Ⅲ）Mandibular Nerve

It is a mixed nerve and the largest division of the trigeminal nerve.

smaller anterior trunk: mainly motor n.

Leaving skull through oval foramen---------

larger posterior trunk: mainly sensory n.

1. Auriculotemporal n

Arising by two rootsencircling meningeal a. piercing parotid glandtemporal regionskin of temporal area.

Parasympathetic secretory fibres from glossopharyngeal n. auriculotemporal n. parotid gland.

2. Buccal n.

It supplies the skin and mucous membrane of the check.

3. Lingual n.

general sense--anterior 2/3 mucous membrane of tongue and floor of oral cavity.

ligual n.

special sense: chorda tympani tastefibres-------------tastebud of anterior 2/3 tongue.

(taste sense) of facial n. parasympathetic secretory fibres---------------

lingual n.

-------------------submandibular ganglion (relay) ----submandibular and lingual gland.

4. Inferior alveolar n.

terminal branch

A mixed n. submanidibular foramen, canalinfeior alveolar plexus-------------------------

mental foramenmental n.

sensory fibres----lower teeth, gum, skin and mucous membrane of chin and lower lip.

Moter fibres ----mylohyoid and anterior belly of digastric m.

5. Nerve of muscles of mastication

It innervates all muscles of mastication.

Ⅵ. Abducent Nerve (CN Ⅵ)

Arising from abducent nucleuspontomedullary groovein cavernous sinus lateral to internal carotid a. superior orbital fissureorbitsupplying lateral rectus m.

Ⅶ. Facial Nerve (CN Ⅶ)
special visceral motor fibres (facial nucleus)

general visceral motor fibres (superior salivatory mucleus)

special visceral sensory fibres (geniculate ganglion)

Emerging from pontomedullary groove lateral to abducent n. internal acoustic meatusfacial canalstylomastoid foramenpiercing parotid glandface.

Ⅰ）The Vranches within the Facial Canal

lingual n. taste fibrestaste bud of anterior 2/3 tongue.

Chorda tympani-----------

parsympathetic fibressubmandibular ganglion

submandibular and lingual gland.

Ⅱ）The Branches outside the Facial Canal

Facial n. parotid plexus (in parotid gland ) five branches

temporal branch: frontal m. and orbicularm. Of eye.

zygomatic branch: zygomatic m. and orbicular m. of eye.

buccal branch: buccinatorm. And orbicular m. of mouth.

mandibular branch: m. of lower lip.

cervical branch: platysma m.

The facial n. also gives off amall muscular branches to occipital m., posterior auricular m., posterior belly of digastric m., and stylohyoid m.

Ⅷ. Vestibulocochlear (Auditory ) Nerve (CN Ⅷ)

cochlear part (nerve) --------auditory sense

Two parts

vestibular part (nerve) --------balance sense (equilibrium)

Ⅰ）Vestibular Nerve

Macula of utricle and sccule peripheral processes

Ampullary crest of membranous ←————————vestibular ganglion

semicircular canal

central processes

(in bottom of internal acoustic meatus)——————→vestibular n. →internal acoustic meatus

enter skull

——————→vestibular nuclei (in brain stem).

Ⅱ）Cochlear Nerve

peripheral central

Spiral organ←——————spiral ganglion (in modiolus)——————→internal acoustic

processes processes

meatus→pontomedullary groove→dorsal and ventral cochlear nuclei (in brain stem).

Ⅸ. Glossopharyngeal Nerve (CN Ⅸ)
special visceral motor fibres

general visceral motor fibres (parasympathetic fibres)

special visceral sensory fibres

general visceral sensory fibres

general somatic sensory fibres

This nerve is a mixed n. in nature and origins on the posterolateral sulcus in the medulla oblongata. It leaves the skull with the vagus nerve and accessory nerve through the jugular foramen. On its trunk there are two sensory ganglia, the superior and inferior.

Ⅰ）Tympanic Nerve

Tympanic n. tympanic plexuslesser petrosal n. otic ganglionauriculotemporal n. parotid gland.

Ⅱ）Carotid Sinus Branch

They run downward along internal carotid artery to supply the carotid body and carotid sinus.

Ⅲ）Lingual Branches

They supply the posterior third of the mucous membrane and taste bud of tongue for general and taste sense.

Ⅹ. Vagus Nerve (CN Ⅹ)

It is the mixed nerve of the longest route and widest distribution.

viscera in cervical part, and thoracic

general visceral motor fibres: and abdominal cavity innervating cardiac,

(parasympathetic fibres) smooth., and gland.

visera in cervical part and

general visceral sensory fibres:

thoracic and abdominal cavity

general somatic sensory fibres: dura mater, skin of auricle and external acoustic meatus.

special visceral motor fibres: laryngeal and pharyngeal m., soft palate.

Emerging from posterolateral sulcus in medulla oblongataleaving skull through jugular foramenforming superior and inferior ganglianeckdescending within carotid sheath (behind internal jugular v. and internal carotid or common carotid a. ) root of necksuperior thoracic aperturethoracic cavity:

anterior gastric branch

abdominal cavity-----

posteror gastric branch

Ⅰ）The Branches in the Neck

Inferior ganglionmedial to internal carotid a. greater cornu of hyoid bone

internal laryngeal branchcricothyroid m.

------- esternal laryngeal branchpiercing thyrohyoid membranemucous membrane of larynx above slit of glottis for sense.

Ⅱ）The Branches in the Thorax

Recurrent laryngeal nerve

Right: higher, winding right subclavian a.

-----groove between trachea and esophagus

Left: lower, winding aortic arch

lower border of inferior pharyngeal constrictor m. inferior laryngeal n. larynx.

Motor fibres: all laryngeal m. except cricothyroid m.

Sensory fibres: mucous membrane of larynx below the slit of glottis

Ⅲ）The Branches in the Abdomen

1. Anterior gastric branch

along lesser curvature of stomach

Anterior vagal trunkanterior gastric branch-------------------------------------------------------

anterior gastric wall

4~6 small branches -----------------------------terminating in “crow’s foot” anterior wall of pyloric part (canal and antrum)

2. Hepatic branch

Anterior wagal trunkhepatic branchhepatic plexus

3. Posterior gastric branch

along lesser curvature of stomach

Posteror vagal trunkposterior gastric branch-------------------------------------------------4~6

posterior gastric wall

small branches---------------------------------terminating in “crow’s foot” posterior wall of pyloric part (canal and antrum)

4. Celiac branch

Posterior vagal trunkceliac branchceliac plexussupply­ing liver, pancreas, kidneys, spleen, small intestine, caccum, transverse colon, ascending colon, appendix, (digestive canal prior to left colic flexure)

Ⅺ. Accessory Nerve (CN Ⅺ)

It is a motor nerve (special visceral motor fibres ), formed by the union of the cranial and spinal roots.

Ⅻ. Hypoglossal Nerve (CN Ⅻ)

It is mainly composed of somatic motor fibres.

Hypoglossal n. (hypoglossal nucleus ) emerging from anterolateral sulcus of medulla oblongataleaving skull through hypoglossal canalbetween internal carotid a. and internal jugular v. supplying all extrinsic and intrinsic m. of tongue.

Section 3 The Visceral Nervous System

The visceral nervous system has two group of fibres, i.e. sensory fibres and motor fibres, is a part of the nervous system distributed in the viscera, cardiovascular system and secretory glands. The motor fibres are also termed autonomic or vegetative fibres because they regulate the common involuntary metabolic activities of the animal and vegetable.

Ⅰ. Visceral Motor Nerves

Differences between Visceral and Somatic Motor Nerves

Somatic n. Visceral n.

1. skeletal m. cardiac m. smooth m., and gland sympathelic fibres 2. one kind of fibres two parasympathetic fibres 3. a single neuron two neurons (lower cntre effector) preganglionic neuron (fibre) postganglionic neuron (fibre) 4. distributed in the form of nerve trunk nerve plexus 5. thick myelinated fibres preganglionic-thin myelinated fibres postganglionic-unmyelinated fibres 6. voluntary involuntary consciousness unconsciousness

In visceral motor nerve, two neurons are needed from lower nervous centres to effector.

The visceral motor nerve is divide into the sympathetic and parasympathetic division on basis of their features in function, shape, pharmacology and neurobiachemisty.

Ⅰ）Sympathetic System

1. Position of lower centres

They are situated in lateral grey horn of T₁ (C₈ ) ~L₂ (L₃ ) segments of the spinal cord. This division is also termed the thoracolumbar part.

2. Peripheral part

prevertebral ganglion

sympathetic ganglion

branches from the ganglia

sympathelic plexus

3. Sympathetic ganglia

1) Parasympathetic ganglia

They arranged symmetrically on either side of the spinal colum, and are connected by interganglionic branches to form two sympathetic trunks, that extend from the base of the skull to the coccyx and are divided into cervical, thoracic, lumbar, sacral and coccygeal portions. Ganglion impar is unpaired ganglion formed by fusing of two sympathetic trunks at the coccyx.

2) Prevertebral ganglia

They are located in front of vertebral column.