PNS

Question 1

Neural crest cells and their differentiation

Question 2

Ventral and dorsal spinal nerve root, dorsal root ganglion, draw general structure of the spinal nerve and its branches, autonomic fibers of spinal nerve

Question 3

Segmental innervation, radicular areas, dermatomes, Head ́s zones (zones of reffered visceral pain), sensory receptors, peripheral nerve regeneration

Question 4

Cervical plexus, supraclavicular portion of brachial plexus

→

pectoralis major and minor

Answer 4

Cervical plexus

• Formed by the anterior rami of cervical nerves C2 to C4,
• Muscular (or deep) branches;
• Cutaneous (or superficial) branches.

Muscular branches

• Phrenic nerve
  
  • which supplies the diaphragm with both sensory and motor innervation
  • Arises from the anterior rami of cervical nerves C3 to C5.
  • Hooking around the upper lateral border of the anterior scalene muscle→ continues inferiorly across the anterior surface of the anterior scalene within the prevertebral fascia → enter the thorax
    
    • As the nerve descends in the neck, it is “pinned” to the anterior scalene muscle by the transverse cervical and suprascapular arteries.
• Several muscular branches
  
  • Supply prevertebral and lateral vertebral muscles:
    
    • Rectus capitis anterior,
    • rectus capitis lateralis,
    • longus colli,
    • longus capitis
• Contributes to the formation of the superior and inferior roots of the ansa cervicalis
  
  • This loop of nerves receives contributions from the anterior rami of the cervical nerves C1 to C3 and innervates the infrahyoid muscles.
  • Superior root: motor beanchs of the cervical plexsus
    
    • Travels with hypogloddus n. but does not exchange fibers
    • leaves hypoglossal n. as it passes the internal carotid a. and disends to join inferior root
  • inferior root
    
    • motor branchs from cervical plexsus, j

Cutaneous (superficial) branches

• Lesser occipital nerve
  
  • Contributions from cervical nerve C2
  • Ascends along the posterior border of the sternocleidomastoid muscle→ distributes to the skin of the neck and scalp posterior to the ear
• Great auricular nerve
  
  • Cervical nerves C2 and C3
  • Emerges from the posterior border of the sternocleidomastoid muscle → ascends across the muscle to the base of the ear→ supplying the skin of the parotid region, the ear, and the mastoid area;
• Transverse cervical nerve
  
  • Cervical nerves C2 and C3
  • Passes around the midpart of the sternocleidomastoid muscle, → continues horizontally across the muscle → supply the lateral and anterior parts of the neck
• Supraclavicular nerves
  
  • Cervical nerves C3 and C4
  • Emerging from beneath the posterior border of the sternocleidomastoid muscle → descend and supply the skin over the clavicle and shoulder as far inferiorly as rib II.

——————————

Brachial plexus

• Brachial plexus is a nervous plexus providing motor and sensitive innervations of the upper extremity.
  
  • It is formed by union of anterior branches of spinal cord segments C5 – C8
  • They get connections from segments C4 (cranially) and T1 (caudally).
• The whole plexus (together with subclavian artery) →The whole plexus (together with subclavian artery) passes scalenic fissure, c→continues below the clavicle in the axillary fossa → divides into two parts
  
  • Supraclavicular part
  • Infraclavicular part of the brachial plexus.

Supraclavicular part of brachial plexus

• Initial part of brachial plexus→ in which three trunks are formed:
  
  • Superior trunk
  • Middle
  • Inferior.
• Nerves for shoulder girdle muscles originate from this part.
• That means that from supraclavicular part of the brachial plexus:
  
  • Spinohumeral muscles (all except trapezius, which is innervated by accessory nerve)
  • Thoracohumeral muscles
  • Shoulder muscles.

DORSAL SCAPULAR NERVE (C5 and C6) –

• Over levator scapulae →descends dorsally together with dorsal scapular vessels
  
  • However on individual specimens of extremities is usually missing or is “loose”.
• whole second layer of back muscles
  
  • Rhomboid major and minor
  • levator scapulae

SUPRASCAPULAR NERVE (C4 - C6) –

• Can be found easily in scapular notch (see topography),
  
  • in which it lies under the superior transverse scapular ligament.
  • Its passage through spinoglenoid notch, where it underlies the inferior transverse scapular ligament, usually it is covered by muscles and is not visible.
• supraspinatus; infraspinatus; variation m. teres minor

LONG THORACIC NERVE (C5 and C6) –

• Descends on fleshy slips of serratus anterior.
  
  • On dissected extremities usually looses it’s connection with a muscle and remains “loose”.
• Serratus anterior m.
• Injury causes functional defects of serratus anterior.
  
  • Scapula is not fixated to thorax enough.
  • That causes winged scapula („scapula alata“)
  • Movement of the arm is limited – particularly abduction of the arm above horizontal

THORACODORSAL NERVE (C6 - C8)

• Located at the inner (anterior) surface of latissimus dorsi.
• Like the previous nerve, the connection to the muscle does not remain and we are more likely to find only the part entering the muscle.
• latissimus dorsi

SUBSCAPULAR NERVES (C5 - C7) –

• can be found as thin branches going to costal surface of the scapula (right into ventral surface of subscapularis) – usually on dissected specimen only parts entering the muscle are preserved.
• subscapularis; teres major

NERVE TO SUBCLAVIUS (C5 and C6) –

• usually is not preserved on the specimen
• subclavius m

LATERAL AND MEDIAL PECTORAL NERVES (C5 - T1) –

• usually two nerves entering pectoral muscles and often are visible on their dorsal surface.
• Lateral pectoral nerves can be found also in the depth of clavipectoral triangle.
• M: pectoralis major and minor
• L: pectoralis major

SUBSCAPULAR NERVES (C5 - C7) – can be found as thin branches going to costal surface of the scapula (right into ventral surface of subscapularis) – usually on dissected specimen only parts entering the muscle are preserved.

Question 5

Infraclavicularis portion of brachial plexus (draw scheme) and upper limb innervation

Answer 5

Infraclavicular part of the brachial plexus

Distal to the clavicle.

• 3 cords (fascicles) are formed from primary trunks three –
  
  • lateral cord,
  • medial cord
  • posterior cord.

These cords give branches to nerves for motor and sensitive innervations of the free part of the upper extremity

Names of these three cords are derived from their relation to axillary artery, which they enclose.

Identification:

For their 100% identification we must find 4 nerves first – musculocutaneous nerve, median nerve, ulnar nerve and radial nerve.

Musculocutaneous nerve is easily found after we look for coracobrachialis m. which this nerve penetrates.

Median nerve is located in cubital fossa, which the nerve enters together with brachial vessels and thanks to its strength the nerve is quite noticeable.

Ulnar nerve can be found easily at entry to cubital canal behind medial epicondyle of humerus (see below) in groove for the ulnar nerve (“funny bone”).

Radial nerve runs around the distal third of the humerus in laterodistal way (in groove for radial nerve) together with deep brachial vessels between lateral and medial head of triceps.

Then we use our knowledge of which nerve is a branch of which cord. We hold ulnar nerve and median nerve at the same time and continue in proximal way.

On median nerve we come to bifurcation (connection of medial root and lateral root of median nerve).

On ulnar nerve we come straight to medial cord, in a place where medial cord gives medial root of median nerve.

In similar way we proceed with lateral cord. We take in hand (forceps) median nerve and musculocutaneous nerve.

On our proximal way we get again to the bifurcation of median nerve and with musculocutaneous nerve straight to lateral cord at the place of branching of lateral root of median nerve. Then let’s move to the last cord, posterior cord. We will continue in proximal way on radial nerve behind axillary artery. Proximal from the branching of axillary nerve (only branch of posterior cord), which runs dorsally to humerotricipital foramen (see topography) together with posterior circumflex vessels of the humerus, lies the axillary nerve. We will find the individual nerves of infraclavicular part of brachial plexus in following way:

MUSCULOCUTANEOUS (NERVE C5 - C7) – easily to be found in the place of its perforation of coracobrachialis (see above).

Question 6

Radial and axillary nerve, paralysis of them

Question 7

Median and ulnar nerve, paralysis of them

Answer 7

MEDIAN NERVE (C6 - T1) – beside it’s course on the arm together with brachial vessels and in cubital fossa (and following in pronator canal – see topography) we can find median nerve easily in carpal canal (see topography) just under the flexor retinaculum, where it emerges on the surface from the depth of the forearm, where it runs between 2nd and 3rd layer of anterior group of muscles of the forearm.

MEDIAN NERVE:

• Whole anterior group of muscles of the forearm
  
  • WITH EXCEPTION OF FLEXOR CARPI ULNARIS AND PART OF FLEXOR DIGITORUM PROFUNDUS FOR 4th AND 5th DIGIT!!!
  • pronator teres
  • flexor carpi radialis
  • palmaris longus
  • flexor digitorum superficialis
  • part of flexor digitorum profundus for 2nd and 3rd digit
  • flexor pollicis longus
  • pronator quadratus
• muscles of the thenar
  
  • WITH EXEPTION OF ADDUCTOR POLLICIS AND DEEP HEAD OF FLEXOR POLLICIS BREVIS!!!
  • abductor pollicis brevis
  • superficial head of flexor pollicis brevis
  • opponens pollicis
• lumbricales I and II

Median nerve

Injury of median nerve usually occurs in anatomically narrowed spaces, which median nerve crosses (carpal tunnel – „carpal tunnel syndrome”, pronator canal, between heads of flexor digitorum superficialis, etc.), in axilla by dislocations in shoulder joint or is caused by stab or shoot wounds and by fractures of the wrist (for example Colles’ fracture) or by incisions („suicide wrist“).

Motor changes in median nerve palsy include inability of pronation (pronators are paralyzed), inability of opposition and thumb flexion (paralysis of opponens pollicis and thumb flexors – beside deep head of flexor pollicis brevis; which is the biggest difficulty for the patient - „apelike hand“) and inability of flexion of 2nd and 3rd finger (flexor paralysis). Flexion of 4th and 5th finger remains, thanks to innervations exception of anterior muscle group of the forearm – ulnar half of flexor digitorum profundus, which is innervated by ulnar nerve. The causes together form „preachers´s hand“ – see the picture.

ULNAR NERVE (C7 – T1) – beside in the groove for ulnar nerve and in the cubital canal, we can easily identify the nerve in ulnar canal (see topography), in which it runs with ulnar vessels.

ULNAR NERVE:

• from anterior group of muscles of the forearm flexor carpi ulnaris and part of flexor digitorum profundus for 4th and 5th digit
  
  • (INNERVATION EXCEPTIONS!!! – see above);
• from thenar muscle groupu deep head of flexor pollicis brevis and adductor pollicis
  
  • (INNERVATION EXCEPTIONS!!! – see above);
• all other muscles of the hand
  
  • (palmaris brevis; abductor digiti minimi; flexor digiti minimi brevis; opponens digiti minimi; lumbricales III and IV; palmar and dorsal interossei)

Ulnar nerve

Ulnar nerve is injured most likely in anatomically narrowed space, which the nerve crosses (cubital canal and ulnar canal/Guyoni/) and in fractures of the forearm and elbow joint area (often together with median nerve).

Typical motor sign of ulnar nerve palsy is „claw hand“ – see the picture. In normal conditions is tonus of the muscles of the forearm in balance with tonus of muscles of the hand. This balance is disturbed in ulnar nerve palsy. Flexors (innervated by median nerve) and extensors (innervated by radial nerve) of fingers dominate. This imbalance causes extension in metacarpophalangeal joints (increased influence of extensors) and flexion in proximal and terminal interphalangeal joints (increased influence of flexors). Most noticeable position is at 4th and 5th finger (lumbricales of 2nd and 3rd finger are innervated by median nerve). At the same time thumb is in abduction (adductor pollicis is paralysed) and whole hand is in radial abduction (paralysis of flexor carpi ulnaris and lumbricales III and IV). Also, because of denervation of interossei, it is not possible to adduct and abduct fingers. These muscles are affected by denervation atrophy, which is manifested by dilatated intermetacarpal spaces.

Another sign of ulnar nerve palsy is Froment’s sign. Patient is not able to hold a sheet of paper between thumb and index finger without flexion in thumb’s interphalangeal joint. That is caused by compensation of not functioning adductor pollicis by flexor pollicis longus (innervated by median nerve).

Question 8

Skin and motor innervation of head and neck

Question 9

Lumbar plexus and its branches

→

Answer 9

Major nerves that originate from the lumbar plexus and leave the abdomen and pelvis to enter the lower limb include:

• Iliohypogastric n
• Illioinguinal n
• Genitofemoral n
• Lateral curaneuous n
• Femoral nerve
• Obturator nerve

ILIOHYPOGASTRIC NERVE (T12 and L1)

• Most cranial nerve of the plexus.
• Course:
  
  • Emerges laterally from the psoas major m.→
  • Passes between internal oblique and transversus abdominis m.→
  • Runs above the illiac crest travelling ventrocaudally→
  • Terminates in the hypogastic and inguinal regions
• Branchs:
  
  • Muscular branch: internal obliqu m. and transversus abdominis m
  • Lateral cutaneous branch
  • Anterior cutaneus branch: skin aound superifical inguinal ring
• Does not enter the pelvis.

ILIOINGUINAL NERVE (L1)

• Can be found slightly caudaly from previous nerve.
• Course:
  
  • Emerges laterally from the psoas major→
  • Continues bellow illiohypogastric nerve→
  • Enters the pelvis along superior anterior iliac spine→
  • Travels though the inguinal canal
• Innervation:
  
  • Skin of anterior part of scrotum
  • Skin on anterior part of labia majora

GENITOFEMORAL NERVE (L1 and L2)

• Penetrates the psoas major and leaves it on its ventral sirfce
• Branchs:
  
  • Genital branch
    
    • Passes though inguinal canal
    • Innervation:
      
      • cremaster, dartos fascia and a small area on the medial side of the though (men)
      • parts of the labia majora, and small…
  • Femoral branch
    
    • Passes through vascular space
    • Innervation:
      
      • Skin on the medial side of the thigh
• Whereas other nerves of lumbar plexus leaves this muscle along its sides, genitofemoral nerve penetrates the muscle ventrally and along the muscle surface descends towards inguinal ligament.

LATERAL FEMORAL CUTANEOUS NERVE (L2 and L3)

• Course:
  
  • Emerges laterally from psoas major →
  • Runs laterocaudally on the illiacus twards the anterior superior illiac spine→
  • Travels through the muscular space bneath the lateral attachment of the inguinal lig. to reach the lateral thigh
• Innervation:
  
  • SS lateral thigh

FEMORAL NERVE (L2 – L4)

• Course:
  
  • Emmerges laterally from the psoas major→
  • Travels above the iliopsoas→
  • Passes medially though the muscular space to reach anterior thigh and femoral triangle→
  • Splits into muscular and cutaneous branchs.
• Branchs:
  
  • Muscular branchs:
    
    • Anterior group of muscles of the thigh
    • (sartorius; quadriceps femoris);
    • Iliopsoas; pectineus (DIPLONEURAL MUSCLE!)
  • Anterior cutaneous branchs
    
    • SS anterior side of thigh
  • Saphenous nerve
    
    • Terminal SS branch
    • Follows great saphenous vein distally on leg
    • Runs in the adductor cannal→ leaves it ventrally though the vassoadductor lamina
      
      • →accompanied by desending genicular artery under the skin of the knee
    • Branchs:
      
      • Infrapatellar branch
      • Medial cutaneous nerve of leg
• Lesions:
  
  • Causes:
    
    • Fractures of pelvis, luxation in hip joint or during surgeries.
    • Even incorrect application of intramuscular injection can injure the nerve (injections have to be put into lateral part of thigh!).
    • Pressure of enlarged inguinal lymph nodes (tumor) and aneurysm of femoral artery.
  • Main motor signs of femoral nerve palsy
    
    • Paralysis of quadriceps femoris
      
      • Walking without support is not possible,
      • Climbing up the stairs is difficult,
    • Patient is unable to raise thigh from lying down position (rectus femoris paralysis);
    • Standing is unstable, it is not possible to stamp or to stay in crouch.
    • In some cases genu recurvatum – hyperextension in the knee joint, is present

OBTURATOR NERVE (L2 – L4)

• Course:
  
  • Emerges medially from the psoas major→ and passes though the obturator canal
• Branchs:
  
  • Muscular branch: obturator externus
  • Anterior branch
    
    • Whole adductor group of muscles of the thigh
    • pectineus /DIPLONEURAL MUSCLE!/; adductor longus; gracilis; adductor brevis;
  • Posterior branch
    
    • adductor magnus /DIPLONEURAL MUSCLE!/
• Palsy
  
  • Isolated peripheral palsy of obturator nerve is very rare.
  • Motor defects represent weakened function of adductor group of muscles of the thigh
    
    • Decreased ability of adduction and lateral rotation in hip joint.
    • Also crossing of lower extremities is not possible.
  • The nerve can be irritated by enlarged uterus in pregnancy.

Sciatic nerve

• Origin:
  
  • Largest nerve of the body and carries contributions from L4 to S3.
• Course:
  
  • It leaves the pelvis through the greater sciatic foramen inferior to the piriformis muscle,
  • Enters and passes through the gluteal region
  • And then enters the posterior compartment of the thigh where it divides into its two major branches:
    
    • Common fibular nerve
      
      • Posterior divisions of L4 to S2 are carried in the common fibular part of the nerve and the anterior
    • Tibial nerve
      
      • Divisions of L4 to S3 are carried in the tibial part.
• The sciatic nerve innervates:
  
  • All muscles in the posterior compartment of the thigh;
  • the part of adductor magnus originating from the ischium;
  • all muscles in the leg and foot;
  • skin on the lateral side of the leg and the lateral side and sole of the foot.

Gluteal nerves

• Major motor nerves of the gluteal region.
  
  • The superior gluteal nerve
    
    • arries contributions from the anterior rami of
• L4 to S1, leaves the pelvis through the greater sciatic foramen above the piriformis muscle, and
• innervates:
• the gluteus medius and minimus muscles; and
• the tensor fasciae latae muscle.

Question 10

Femoral nerve

Question 11

Sacral plexus and its branches

→

Answer 11

Sacral plexus

• Second nervous plexus for lower extremity.
• It is formed by the union of anterior branches of sacral segments S1 – S5,
  
  • Together with cranial connections from segments L4 a L5 via lumbosacral trunk

SUPERIOR GLUTEAL NERVE (L4 – S1)

• Runs though suprapiriform foramen with superior gluteal vessels
• Innervates the gluteus medius, minnimus and tensor fascia latae

INFERIOR GLUTEAL NERVE (L5 – S2)

• Runs though infrapifiorm foramen with the inferior gluteal artery and vein
• Innervates gluteus maximus

POSTERIOR FEMORAL CUTANEOUS NERVE (S1 – S3)

• Course:
  
  • Runs though infrapirifom foramen→ passes over inferior border of gluteus maxsimus
  • Travels with cranial extension of small saphenous vien
• Innervation:
  
  • SS dorsal thigh
  • Clunial nerve: gluteal region
  • Perineal branchs: perineal skin

PUDENDAL NERVE (S2 – S4)

• Course:

an be found easily after leaving infrapiriform foramen, where the nerve rotates around ischial spine and enters lesser sciatic foramen (together with internal pudendal vessels) and immediately re-enters the pelvis through Alcock’s canal.

SCIATIC NERVE (L4 – S3)

can be easily recognised in the infrapiriform foramen by its noticeable thickness (biggest nerve in human body). However, we have to keep in mind, that the place of division of sciatic nerve is very variable. Usually, the nerve is divided to the tibial nerve and the common fibular nerve before entering popliteal fossa. In some cases this division can occur much higher, for example as high as in infrapiriform foramen the main of sciatic nerve does not have to be presented. So called “high splitting” has influence on motor innervations of muscles of the posterior side of the thigh and on adductor magnus. Usually whole posterior group of muscles of the thigh (biceps femoris, semitendinosus and semimembranosus) together with part of adductor magnus origining on sciatic tuberosity is innervated by sciatic nerve. However, if the nerve splits high enough, these muscles are innervated by tibial nerve and common fibular nerve in a following way: all muscles (or their parts) named above, origining on sciatic tuberosity (long head of biceps femoris, semitendinosus, semimembranosus and part of adductor magnus) are innervated by tibial nerve and only short head of biceps femoris by common fibular nerve.

6.2.3 Superior and inferior gluteal nerve

Palsy of inferior gluteal nerve causes loss of function of gluteus maximus – extension in hip joint is limited (difficulty climbing up the stairs). Damages to superior gluteal nerve causes limited functions of gluteus medius, gluteus minimus and tensor fasciae latae. First two muscles provide abduction in hip joint. Also, their pull have great significance for walking and standing on one leg, where prevents elevation of pelvis on the side where we stand. Trendelenburg’s sign (see the picture) shows defect of this muscle function, elevation of pelvis on the side of the nerve lesion, which is compensated by lateral flexion to the opposite side. Similar sign is shown during walking - „goose gait“.

6.2.4 Sciatic nerve

Traumatic damage of this nerve occurs in pelvis fractures or posterior luxations in hip joint. Non-traumatic compression of nerve is most commonly caused by hematoma or tumour in gluteal region. Scitaic nerve can also be damaged by incorrect application of intramuscular injection (it has to be put always to upper outer quadrant of gluteal region!). Because of sciatic nerve splitting to common fibular nerve and tibial nerve, it’s lesion manifests in similar way as lesion of it’s branches (see below). In less serious forms of palsy there are only limited functions of muscles of posterior group of the thigh (extensors in hip joints and flexors in knee joint. Motor sign is foot drop. Limited function of this muscle group often remains spotless, because extension in hip joint is compensated by gluteal muscles and flexion in knee joint by gastrocnemius. More serious nerve damages makes walking impossible.

6.2.5 Tibial nerve

Injuries of tibial nerve are often caused by serious traumas in hip joint (dislocating fractures and luxations). More often is lesion of tibial nerve in his passage in malleolar canal – scission wounds, ankle fractures or compression by tumour or incorrectly put plaster on fractured ankle.

Motor sign is inability of plantar flexion of foot due to triceps surae paralysis (it is not possible to lift the heel and stand on the tiptoes). Also Achilles tendon reflex is reduced. Dorsal flexion of foot is present (due to tibialis anterior) and the patient falls on the heel during walking - „pes calcaneus“.

6.2.6 Common fibular nerve

Compression of common fibular nerve is most likely behind head of fibula, where it covered only by skin layer (for example caused by incorrectly put plaster). Contusion of common fibular nerve can also occur in a place of it’s course between fibularis longus and fibula (fibular canal). Common are also stretch injuries of the nerve in luxations or distortions of knee joint.

Motor symptoms show weakened functions of innervated muscles. Due to loss of function of muscles of anterior group of the leg plantar foot drop occurs, which causes ”flopping” during walking. Patient tries to compensate this by raising the legs high „rooster gait“. Also standing on heels is not possible. Foot arch is depressed, because tibialis anterior and fibularis longus are paralysed.

Question 12

Sciatic nerve, paralysis of common peroneal nerve

Question 13

Overview of muscular and skin innervation of lower limb

Question 14

First and second branch of trigeminal nerve, sensory trigeminal nuclei

→

379

Axons of the neurons in the main sensory and spinal nuclei and the central processes of the cells in the mesencephalic nucleus

cross the median plane and ascend as the trigeminal lemniscus to terminate on the nerve cells of the ventral posteromedial nucleus of the thalamus.

The axons of these cells now travel through the internal capsule to the postcentral gyrus (areas 3, 1, and 2) of the cerebral cortex.

Answer 14

Trigeminal Nerve (Cranial Nerve V)

• Largest cranial nerve
• Contains both sensory and motor fibers.
• It is the sensory nerve to the greater part of the head and the motor nerve to several muscles, including the muscles of mastication

Trigeminal Nerve Nuclei, four nuclei:

(1) the main sensory nucleus

• Posterior pons, lateral to the motor nucleus
• It is continuous below with the spinal nucleus
• Fine touch, pressure, vibration, proptioception

(2) the spinal nucleus

• Extends inferiorly through MO and into the upper part of the spinal cord as far as the second cervical segment
• Crude touch, pain and tempature
  
  • From V/1 (ophthalmic): inferior part of the spinal nucleus
  • From V/2 (maxillary): middle of the spinal nucleus;
  • From V/3 (mandibular): superior part of the spinal nucleus.

(3) the mesencephalic nucleus

• Most dorsal ncl
• Unipolar nerve cells situated in the lateral part of the gray matter around the cerebral aqueduct.
• Proprioception from masticatory, mimetic and extra-ocular muscles
• * feedback loop with V motor ncl: optimal masticatory tension and prevents damage of teeth (ex. bite tounge…)

(4) the motor nucleus

• In the pons medial to the main sensory nucleus
• AF:
  
  • Corticonuclear fibers from both cerebral hemispheres
  • RF, red nucleus, the tectum, and the medial longitudinal fasciculus.
  • Mesencephalic ncl: Forming a monosynaptic reflex arc.
• innervation of muscles of 1st pharyngeal arch:
  
  • masticatory (masseter, temporalis, lateral and medial pterygoid
  • tensor tympani,
  • tensor veli palatini
  • anterior belly of diagastric
  • mylohyoid

Course of the Trigeminal Nerve

• Leaves the anterior aspect of the pons→
  
  • Small motor root
  • Large sensory root.
• Out of the posterior cranial fossa→ rests on the upper surface of the apex of the petrous part of the temporal bone in the middle cranial fossa.
  
  • The large sensory root → forms trigeminal ganglion
    
    • Lies within a pouch of dura mater called the trigeminal or Meckel cave.

The ophthalmic, maxillary, and mandibular nerves arise from the anterior border of the ganglion:

Ophthalmic nerve (V1), SS

Leaves the skull through the superior orbital fissure → enter the orbital cavity.

Branchs:

• Tentorial nerve (a meningeal branch)
• Lacrimal nerve: along lateral rectus twards lacrimal gland
  
  • Recieves communicating branch from zygomatic n.
  • Skin of lateral part of eylid and ajcacent conjunctiva
• Frontal nerve
  
  • Supra-orbital nerve: skin upper eylid​
    
    • Medial branch: Leaves orbit thorugh frontal notch
    • Lateral branch: Leaves orbit through subraorbital notch
  • Supratrochlear nerve
    
    • Skin and conjunctiva medial part of eye
• Nasociliary nerve: from lateral part of the orbit to its medial wall
  
  • Communicating wtih cillary ggl:
    
    • Short ciliary nerves
  • Long ciliary nerves: sensory innervation of eye ball
  • Anterior ethmoidal nerves: via anterior ethmoid foramen, orbitoethmoid canal→cribriform plate→nasal cavity )frontal sinus, anterior nasal mucosa
  • Posterior ethmoidal nerves: via posterior ethmoid foramen, orbitoethmoid canal
  • Infratrochlear nerves: terminal branch, medial branch of moth eyelids and conjunctiva

Maxillary nerve (CN V2), SS

• foramen rotundum
• 6 branches in fossa pterygopalatina

Leaves the middle cranial fossa: foramen rotundum → upper part of the pterygopalatine fossa: most of its branches: ppg ggl …→

through pterygomaxillary fissure → infratemporal fossa: Adjacent to the maxillary tuberosity →turns medially → enters the orbit: inferior orbital fissure: terminal branch: infraorbital n.

1- Meningeal branch: before entrance to foramen rotundum

2- Zygomatic nerve

Pterygopalatine fossa → forward and laterally→ through pterygomaxillary fissure → infratemporal fossa→ inferior orbital fissure → enters the orbit → While inside the orbit courses along its lateral wall → enters canal present in the zygomatic bone.

• Canal itself also has two hallways that correspond to these terminal branches:
  
  • Anterior zygomaticofacial nerve
  • Posterior zygomaticotemporal nerve
• Exit the zygomatic canal through the proper foramina named according to the branches: innervate the adjacent parts of the skin.

On the lateral wall of the orbit, the zygomatic nerve makes anastomosis with the lacrimal nerve through their common connective branch.

• Thanks to this anastomosis, parasympathetic fibers from the pterygopalatine ganglion reach the lacrimal gland.

Infra-orbital nerve

• ​Terminating branch
• Through the inferior orbital fissure → forward and medially→ over the inferior wall of the orbit→ though infraorbital sulcus → then to the infraorbital canal →exits the infraorbital canal: though infraorbital foramen → then divides into its many ending branches:
  
  • External nasal branches that innervate the skin that covers the side of the nose
  • Internal nasal branches which provide sensory innervation to the nasal septum
  • Superior labial branches that innervate the upper lip
  • Inferior palpebral branches that provide innervation for the lower eyelid
• During its pathway through the infraorbital sulcus, this nerve courses closely to the maxillary sinus.
• In this part of its path, the infraorbital nerve extends to the following branches:
  
  • Anterior superior alveolar branches
  • Middle superior alveolar branch
• These branches, together with the posterior superior alveolar branches, participate in making sup. dental plexus

2- Ganglionic branches to (sensory root of) pterygopalatine ganglion

• Short, course inferiorly and medially towards the pterygopalatine ganglion.
• Sensory AF branches for the ganglion.
• Receive 1-2 EF branches from the ganglion.
  
  • n. petrosus major (VII) parasympathetic
    
    • Through the pterygopalatine nerves: reach the zygomatic nerve.
    • These pterygopalatine nerves give rise to the many branches, of which the most important are branches for the nasal cavity and the palatine nerves.

From PP GGL:

• Branches for the nasal cavity: through the sphenopalatine foramen:
• Nasopalatine n.
  
  • ​hard plate, nasal septum
  • Enters the incisive canal where it makes anastomosis with the incisive nerve of the contralateral side, and with the greater palatine nerve.
• Posterior nasal n.
  
  • Superior posterior nasal- Lateral (LSPN) branches
    
    • Provide sensory innervation to the mucosa of the superior and middle nasal concha
  • Superior posterior nasal- Medial (MSPN) branches,
    
    • Provide sensory innervation: nasal septum which they innervate.
• Pharyngeal nerve: mucosa pharynx and auditory tube
• Palatine nerves
  
  • Extend from the pterygopalatine nerves inferiorly.
• Greater palatine n.
  
  • Enters the greater palatine canal following the same named artery→ leaves the canal through the major palatine foramen with artery→ courses medially and forwards → end in the area of the incisive fossa:
  • Anastomosis with the contralateral major palatine nerve and with the nasopalatine nerve.
  • innervates the mucosa of the hard palate.
• Lesser palatine nerves
  
  • Descend together with the major palatine nerve through the pterygopalatine fossa→ separate from→ course posteriorly through the bone canals of the lesser palatine nerves → reach the soft palate which they innervate.

Question 15

Third branch of trigeminal nerve

→

Answer 15

Trigeminal Nerve (Cranial Nerve V)

• Largest cranial nerve
• Contains both sensory and motor fibers.
• It is the sensory nerve to the greater part of the head and the motor nerve to several muscles, including the muscles of mastication

Trigeminal Nerve Nuclei, four nuclei:

(1) the main sensory nucleus

• Posterior pons, lateral to the motor nucleus
• It is continuous below with the spinal nucleus
• Fine touch, pressure, vibration, proptioception

(2) the spinal nucleus

• Extends inferiorly through MO and into the upper part of the spinal cord as far as the second cervical segment
• Crude touch, pain and tempature
  
  • From V/1 (ophthalmic): inferior part of the spinal nucleus
  • From V/2 (maxillary): middle of the spinal nucleus;
  • From V/3 (mandibular): superior part of the spinal nucleus.

(3) the mesencephalic nucleus

• Most dorsal ncl
• Unipolar nerve cells situated in the lateral part of the gray matter around the cerebral aqueduct.
• Proprioception from masticatory, mimetic and extra-ocular muscles
• * feedback loop with V motor ncl: optimal masticatory tension and prevents damage of teeth (ex. bite tounge…)

(4) the motor nucleus

• In the pons medial to the main sensory nucleus
• AF:
  
  • Corticonuclear fibers from both cerebral hemispheres
  • RF, red nucleus, the tectum, and the medial longitudinal fasciculus.
  • Mesencephalic ncl: Forming a monosynaptic reflex arc.
• innervation of muscles of 1st pharyngeal arch:
  
  • masticatory (masseter, temporalis, lateral and medial pterygoid
  • tensor tympani,
  • tensor veli palatini
  • anterior belly of diagastric
  • mylohyoid

Course of the Trigeminal Nerve

• Leaves the anterior aspect of the pons→
  
  • Small motor root
  • Large sensory root.
• Out of the posterior cranial fossa→ rests on the upper surface of the apex of the petrous part of the temporal bone in the middle cranial fossa.
  
  • The large sensory root → forms trigeminal ganglion
    
    • Lies within a pouch of dura mater called the trigeminal or Meckel cave.

The ophthalmic, maxillary, and mandibular nerves arise from the anterior border of the ganglion:

Mandibular nerve [V3]

Trigeminal ganglion →leaves the skull through the foramen ovale

Motor root: also passes through the foramen ovale and unites with the sensory component of the mandibular nerve [V3] outside the skull.

EF branchs:

• Branches at level of the mandibular tubercle→
  
  • Deep temporal nn. (anterior & posterior), or auricular??????????
  • Nerve of the lateral pterygoid muscle
  • Mandibular notch→ Masseteric n
  • Nerve of the tensor veli palatine muscle
  • Nerve of the medial pterygoid muscle.
  • Nerve of the tensor palatini muscle
  • Inf. alveolar n. → Mylohyoid n (SM, SS), also innervates ant. diagastic belly
  • Motoric and aid swallowing.
• These nerves innervate their corresponding muscles motorically and aid in speech and mastication.

AF

Meningial branch

Buccal nerve

• (not to be confused with the nerve innervating the buccinator muscle).
• skin, mucosa and glands of cheek

Auriculotemporal n

• froms loop around middle miningeal artery
• innervates part of the auricle and skin

Inferior alveolar n (synapse in otic ggl)

• Inferior dental plexus
• mandibular f. and c →mental f. →Mental nerve
• innervates the mandibular teeth and gums with sensory fibers.

Lingual nerve (synapse in otic ggl)????????????????

• Innervates the tongue, the floor of the mouth and the submandibular glands and sublingual glands
  
  • SS: from trigeminal n.
  • Parasympathetic: from the chorda tympanii of the facial nerve (CN VII).
  • Course:
    
    • Go straight into the tongue: control taste in the anterior two-thirds of the tongue
    • Synapse in the submandibular ganglion as parasympathetic fibers and the postganglionic fibers innervate the salivary glands.

Reflex examination

• masseter reflex
• corneal reflex

Herpes zoster ophthalmicus (V1)

Palsy of nervus trigeminus - unilateral

• sensory disturbance in face, motor palsy ofmasticatory muscles – very rare!
• Neuralgie trigeminalis – irritation pain in area suppliedby somatosensory fibres

Question 16

Oculomotor, trochlear, abducens nerve

→

379

•Palsy of n. VI strabismus convergens = convergent squint

Anulus tendineus communisZinni

passing through:

• n. III
• n. VI
• n. nasociliaris
• n. II + AO

•

passing by:

• n. IV
• n. frontalis
• n. lacrimalis
• VOS

Answer 16

• Trochelar: most medial*
• Abducens: most lateral*

Oculomotor Nerve (Cranial Nerve III)

• Entirely motor in function.

Oculomotor Nerve Nuclei, Two motor nuclei:

(1) the main motor nucleus

• Situated in the anterior part of the gray matter that surrounds the cerebral aqueduct of the midbrain
  
  • At the level of the superior colliculus.
• Supply all the extrinsic muscles of the eye
  
  • Except: superior oblique and the lateral rectus.
• EF:
  
  • Fibers pass anteriorly through the red nucleus and emerge on the anterior surface of the midbrain in the interpeduncular fossa.
• AF:
  
  • Corticonuclear fibers from both cerebral hemispheres.
  • Tectobulbar fibers from the superior colliculus:
    
    • Through this route, receives information from the visual cortex.
  • Medial longitudinal fasciculus
    
    • By which it is connected to the nuclei of the fourth, sixth, and eighth cranial nerves.

(2) the accessory parasympathetic nucleus.

• (Edinger-Westphal nucleus)
• Situated posterior to the main oculomotor nucleus
• Preganglionic axons accompany the other oculomotor fibers to the orbit→ Synapse in the ciliary ganglion → postganglionic fibers pass through the short ciliary nerves:
  
  • to the constrictor pupillae of the iris and the ciliary muscles.
• AF:
  
  • Corticonuclear fibers for the accommodation reflex
  • Fibers from the pretectal nucleus for the direct and consensual light reflexes

Course of the Oculomotor Nerve

Emerges on the anterior surface of the midbrain→ passes forward between the posterior cerebral and the superior cerebellar arteries → continues into the middle cranial fossa in the lateral wall of the cavernous sinus →

• Divides into a superior and an inferior ramus
  
  • Which enter the orbital cavity through the superior orbital fissure.

Innervation

• The following extrinsic muscles of the eye:
  
  • Levator palpebrae superioris, (superior branch)
  • Superior rectus (superior branch)
  • Medial rectus, (inferior branch)
  • Inferior rectus (inferior branch)
  • Inferior oblique (inferior branch)
• Supplies, through its branch to the ciliary ganglion and the short ciliary nerves, parasympathetic nerve fibers to the following intrinsic muscles:
  
  • Constrictor pupillae of the iris
  • Ciliary muscles.
• Therefore, the oculomotor nerve is entirely motor and is responsible for lifting the upper eyelid; turning the eye upward, downward, and medially; constricting the pupil; and accommodating the eye.

———————————————————————-

Trochlear Nerve (Cranial Nerve IV)

• The trochlear nerve is entirely motor in function.

Trochlear Nerve Nucleus

• Situated in the anterior part of the gray matter that surrounds the cerebral aqueduct of the midbrain
• Lies inferior to the oculomotor nucleus at the level of the inferior colliculus. The nerve fibers, after leaving the nucleus, pass posteriorly around the central gray matter to reach the posterior surface of the midbrain.
• AF: similar to oculomotor nerve
  
  • Corticonuclear fibers from both cerebral hemispheres.
  • Tectobulbar fibers, which connect it to the visual cortex through the superior colliculus
  • Medial longitudinal fasciculus, by which it is connected to the nuclei of the third, sixth, and eighth cranial nerves.

Course of the Trochlear Nerve

Only one to leave the posterior surface of the brainstem: emerges from the midbrain→ immediately decussates → passes forward through the middle cranial fossa in the lateral wall of the cavernous sinus → enters the orbit through the superior orbital fissure.

Innervation

• Superior oblique muscle of the eyeball.
• Assists in turning the eye downward and laterally.

Abducent Nerve (Cranial Nerve VI)

• Small motor nerve that supplies the lateral rectus muscle of the eyeball, turning the eye laterally.

Abducent Nerve Nucleus

• Situated beneath the floor of the upper part of the fourth ventricle, close to the midline and beneath the colliculus facialis
• AF: same as trochlear nerve

Course of the Abducent Nerve

Pass anteriorly through the pons → emerge in the groove between the lower border of the pons and the medulla oblongata → passes forward through the cavernous sinus: lying below and lateral to the internal carotid artery →enters the orbit through the superior orbital fissure.

Lesions

Oculomotor Nerve III :

• extraocular muscles except the superior oblique and the lateral rectus.
• Striated muscle of the levator palpebrae superioris and the smooth muscle concerned with accommodation: the sphincter pupillae and the ciliary muscle.

Complete lesion of the oculomotor nerve

• The eye cannot be moved upward, downward, or inward.
• At rest:
  
  • Eye looks laterally (external strabismus), owing to the activity of the lateral rectus,
  • Downward, owing to the activity of the superior oblique.
  • The patient sees double (diplopia).
  • Ptosis: drooping of the upper eyelid due to paralysis of the levator palpebrae superioris.
  • The pupil is widely dilated and nonreactive to light,
    
    • Paralysis of the sphincter pupillae and unopposed action of the dilator (supplied by the sympathetic).
  • Accommodation of the eye is paralyzed.

Incomplete lesions of the oculomotor nerve

• internal ophthalmoplegia:
  
  • innervation of the extraocular muscles is spared with selective loss of the autonomic innervation of the sphincter pupillae and ciliary muscle
• external ophthalmoplegia:
  
  • sphincter pupillae and the ciliary muscle are spared with paralysis of the extraocular muscles

Trochlear Nerve

• Supplies the superior oblique muscle, which rotates the eye downward and laterally.
• Diplopia

Abducent Nerve

• Supplies lateral rectus: Cannot turn the eye laterally.
• When the patient is looking straight ahead, the lateral rectus is paralyzed, and the unopposed medial rectus pulls the eyeball medially, causing internal strabismus.
• Diplopia.

Vascular Lesions of the Midbrain: Weber Syndrome

• Occlusion of a branch of the posterior cerebral artery that supplies the midbrain
  
  • Results in the necrosis of brain tissue involving the oculomotor nerve and the crus cerebri.
• Ipsilateral ophthalmoplegia and contralateral paralysis of the lower part of the face, the tongue, and the arm and leg.
• The eyeball is deviated laterally because of the paralysis of the medial rectus muscle;
• there is drooping (ptosis) of the upper lid,
• and the pupil is dilated and fixed to light and accommodation.

Question 17

Facial nerve

→

Answer 17

Facial Nerve (Cranial Nerve VII)

• Motor and a sensory nerve.

Facial Nerve Nuclei

Three nuclei:

(1) Main motor nucleus VII

• lower part of the pons
• Somatomotor branchial (2nd arch)
• Part that: supplies the muscles of the upper part of the face
  
  • receives corticonuclear fibers from both cerebral hemispheres.
• Part that supplies: the muscles of the lower part of the face
  
  • receives only corticonuclear fibers from the opposite cerebral hemisphere.

(2) the parasympathetic nuclei: Superior salivatory ncl (VM)

• Posterolateral to the main motor nucleus.

(3) the sensory nucleus: spinal ncl of trigeminal n.

(4) ncl of solitary tract (V)

• ncl. gustatorius (rostral part of ncll. of solitary tract- X )
  
  • VS: (taste), ant. 2/3 of tounge

n. intermedius = VM fibres + taste fibres+ SS →Geniculate ggl
n. intermedius =Superior salivatory ncl (VM)+ ncl. gustatorius (part of ncl of solitary tract V)+spinal ncl of trigeminal nerve (SS)→Geniculate ggl

Course of the Facial Nerve

The two roots of the facial nerve emerge from the anterior surface of the brain between the pons and the medulla oblongata:

• Motor root → travel posteriorly around the medial side of the abducent nucleus→ pass around the nucleus beneath the colliculus facialis in the floor of the fourth ventricle → pass anteriorly to emerge from the brainstem
• Sensory root (nervus intermedius) → geniculate ganglion (also contains the efferent preganglionic parasympathetic fibers from the parasympathetic nuclei)

→Posterior cranial fossa with the vestibulocochlear nerve → enter the internal acoustic meatus in the petrous part of the temporal bone→ enters the facial canal and runs laterally through the inner ear.

On reaching the medial wall of the tympanic cavity, the nerve expands to form the sensory geniculate ganglion→ turns sharply backward above the promontory. →

At the posterior wall of the tympanic cavity: the facial nerve turns downward on the medial side of the aditus of the mastoid antrum→ descends behind the pyramid → emerges from the stylomastoid foramen.

Branchs in facial canal

• Greater petrosal n.
  
  • From geniculum of facial canal → canal for g. petrosal n. →hiatus →groove→ PP fossa→ PP GGL
  • Parasympathetic fibres :ggll. lacrimalis, nasales, palatinae, nasopharyngeael
• Stapedius n.: m. stapedius
• Chorda tympani
  
  • Through canaliculus for chorda tympani→ tympanic cavity: mucosal fold between malleus and stapes→ petrotympanic fissure→ infratemporal fossa→ joins lingual n →submandibular ggl
  • Parasympathetic fibres g gll. linguales, submandibularis + sublingualis
  • Taste: ventral 2/3 of tongue = dorsum linguae

Outside skull

• Posterior auricular n
  
  • Occipital branch
  • Auricular branch
• Diagastic branch: posterior belly diagastric m. and stylohyoid m

From partoid plexsus: 5 motor branchs

• Temporal branchs: facial m. in fronal and temporal regions
• Zygomatic branchs: orbicularis oris m. zygomatic m., nose m.
• Buccal branchs: m. of cheek and upper lip
• Marginal mandibular branchs: m. of chin and lower lip
• Cervial branchs: platysma m. and participates in formation of superfical cervial ansa

Clinical:

Central palsy= Supranuclear lesion

• Lesion between cerebral cortex and nucleus in brain stem
• Palsy of only lower quadrant of face on contralateral side
  
  • Upper quadrent receives corticonuclear fibers from both cerebral hemispheres.
  • Lower quadrent corticonuclear fibers from ipsilateral cerebral hemispheres.

Peripheral palsy

• homolateral
• All the muscles on the affected side of the face will be paralyzed
• Lower eyelid will droop,
• the angle of the mouth will sag.
• Tears will flow over the lower eyelid,
• saliva will dribble from the corner of the mouth.
• Unable to close the eye
• unable to expose the teeth fully on the affected side.
• Emotional movements of the face are usually preserved.
  
  • This indicates that the upper motor neurons controlling these mimetic movements have a course separate from that of the main corticobulbar

Facial Nerve Lesions placment:

• If the abducent nerve (supplies the lateral rectus muscle) and the facial nerve are not functioning, this would suggest a lesion in the pons of the brain.
• If the vestibulocochlear nerve (for balance and hearing) and the facial nerve are not functioning, this suggests a lesion in the internal acoustic meatus.
• If the patient is excessively sensitive to sound in one ear, the lesion probably involves the nerve to the stapedius muscle, which arises from the facial nerve in the facial canal.
• Loss of taste over the anterior two-thirds of the tongue indicates that the facial nerve is damaged proximal to the point where it gives off the chorda tympani branch in the facial canal.
• A firm swelling of the parotid salivary gland associated with impaired function of the facial nerve is strongly indicative of a cancer of the parotid gland with involvement of the nerve within the gland.

Bell Palsy=

• most common form of peripheral facial nerve palsy.
• Within the facial canal; it is usually unilateral.

Question 18

Glossopharyngeal and vagus nerve

→

Answer 18

Glossopharyngeal Nerve (Cranial Nerve IX)

• Overview of function: ​
  
  • Somatic sensory, which provide the sensory input from:
    
    • The posterior one-third of the tongue, palatine tonsils, oropharynx, mucosa of the middle ear, pharyngotympanic tube and the mastoid air cells
  • Visceral sensory:
    
    • that carry the sensory information from the carotid body
  • Special sensory:
    
    • for the sense of taste from the posterior one-third of the tongue
  • Parasympathetic:
    
    • that innervate the salivary parotid gland
  • Motor,
    
    • Which innervate the muscles derived from the third pharyngeal arch, which are:
      
      • The stylopharyngeus muscle
      • The superior pharyngeal constrictor muscle.
• CN IX lesion results in:
  
  • loss of afferent limb of gag reflex,
  • loss of taste from posterior one third of tongue,
  • loss of sensation from pharynx, tonsils, fauces, and back of tongue

The glossopharyngeal nerve has three nuclei:

• (1) Ncl ambiguus (superior end): Main motor nucleus:
  
  • Deep in the reticular formation of the medulla oblongata
  • AF: corticonuclear fibers from both cerebral hemispheres.
  • EF: supply the stylopharyngeus muscle.
    
    • 3rd pharyngeal arch
• (2) Inferior salivatory nucleus (VM): the parasympathetic nucleus
  
  • Upper part of dorsal vagus ncl.
  • AF
    
    • Hypothalamus through the descending autonomic pathways.
    • Olfactory system through the reticular formation.
    • Nucleus of the solitary tract: information concerning taste from the mouth cavity.
  • EF
    
    • Retro olivary groove brainstem→ jugular foramen→ (cell body in inferior ggl of IX?)→
      
      • pharyngeal branchs→ pharyngeal plexsus
      • OR
      • tympanic nerve→ tympanic canaliculus → on promontory of tympanic cavity: tympanic plexsus→ lesser petrosal nerve→ otic ggl→
        
        • buccal glands
        • parotid gland
          
          • with buccal n. and auriculotemporal nerve from V/3
          • for sympathetic: (branchs from superior cervical ggl→ ex. carotid plx →plx middle miningeal a→otic ggl in infratemporal fossa→ parotid and buccal glands)
• ​(3) Ncl of the solitary tr (VS)
  
  • Sensations of taste travel through the peripheral axons of nerve cells situated in the ganglion on the glossopharyngeal nerve.
    
    • Caudal portion of the nucleus receives sensory information from the baroreceptors of the carotid sinus
    • Rostral portion receives gustatory (taste) fibers from the posterior one-third of the tongue.
      
      • The rostral part is because of its function referred to as the gustatory nucleus.
  • EF:
    
    • Efferent fibers cross the median plane and ascend to the ventral group of nuclei of the opposite thalamus and a number of hypothalamic nuclei.
    • From the thalamus, the axons of the thalamic cells pass through the internal capsule and corona radiata to end in the lower part of the postcentral gyrus.
  • AF
    
    • From the carotid sinus (VS): carotid branch
      
      • A baroreceptor situated at the bifurcation of the common carotid artery, also travel with the glossopharyngeal nerve.
        
        • They terminate in the nucleus of the tractus solitarius and are connected to the dorsal motor nucleus of the vagus nerve.
        • The carotid sinus reflex that involves the glossopharyngeal and vagus nerves assists in the regulation of arterial blood pressure.
    • Special sensory: taste
      
      • Pharyngeal branchs
      • Lingual branchs (post 1/3 of tounge)
      • Tonsilar branchs
• 4- Spinal ncl of trigeminal nerve SS
  
  • recieves SS fibers from glossopharyngeal
  • enters the brainstem through the superior ggl of the glossopharyngeal nerve → ends in the spinal nucleus of the trigeminal nerve.
    
    • Tubal branch (only SS)
    • Lingual and tonsilar branch (SS and taste)
    • pharyngeal branch (SS and taste), additional from X and sympath…

Course of the Glossopharyngeal Nerve

• Emerges MO at retro-olivary groove with vagus and accessory nerves→ leaves cranial cavity via jugular foramen→ forms superior ggl above jugular foramen and inferior ggl just below it → after leaving skull, runs between internal carotid A and internal jugular vien→ joins lateral side of stylopharynheous m. (which it innervates) →The nerve then passes forward between the superior and middle constrictor muscles of the pharynx to give sensory branches to the mucous membrane of the pharynx and the posterior third of the tongue

Branchs

The glossopharyngeal nerve, besides the anastomotic branches with the facial nerve, vagus nerve, and the sympathetic fibers, also gives off 5 lateral branches:

• The tympanic nerve - Jacobson
  
  • Parasympathetic branch of the glossopharyngeal nerve that innervates the parotid gland.
  • It separates from the glossopharyngeal nerve directly under the jugular foramen→ enters the tympanic canal →e nters the tympanic cavity→ extends upwards by crossing through the promontory sulcus where it forms the neural tympanic plexus.
    
    • Sympathetic caroticotympanic nerves that extend from the internal carotid plexus also participate in the making of the tympanic plexus, along with the branch of the facial nerve that is called the communicant branch with the tympanic plexus.​​
  • The tympanic plexus sends branches that innervate the mucosa of the middle ear.
    
    • Lesser petrosal nerve:
      
      • From the superior part of the plexus,
      • Through the canal of the lesser petrosal nerve→ it reaches the anterior side of the temporal pyramid→ groove: sulcus of the lesser petrosal nerve→ leaves the cranium as it passes through the sphenopetrosal fissure, and it finally ends in the otic ganglion.
  • Secretory parasympathetic fibers (that originate from the glossopharyngeal nerve) that synapse with the cells of the otic ganglion.
    
    • In that way, the postganglionic fibers in a form of the auriculotemporal nerve reach the parotid gland and supply it with the parasympathetic innervation that is necessary for the proper stimulation of the gland.
• The carotid sinus nerve
  
  • General visceral afferent fibers →reflex lowering of the blood pressure when it is increased.
  • The carotid sinus nerve emerges from the glossopharyngeal nerve from about 0.4 inches (1 cm) beneath the basis of the cranium.
  • It then descends along the body of the internal carotid artery aiming towards the bifurcation of the common carotid artery.
  • This nerve ends by sending terminal branches to the carotid sinus and the carotid body.
• The pharyngeal nerves
  
  • There are usually three of these nerves.
    
    • Create the anastomosis with the branches of the vagus nerve and as well as with the laryngopharyngeal nerves that originate from the cervical sympathetic plexus.
  • With these anastomoses, these nerves build a neural network that is called pharyngeal plexus. The nerves of this plexus innervate many of the pharyngeal muscles, soft palate muscles and the mucosa of the pharynx.
• Stylopharyngeus muscle nerve
• Tonsillar nerves
  
  • These nerves provide sensory innervation to the palatine tonsils and to the mucosa of the isthmus of the fauces.

Terminal branches: lingual branchs

• Ends its course beneath the mucosa of the posterior one-third of the tongue, medially to the styloglossus muscle.
• On this place, the nerve divides into: terminal lingual branches.
  
  • These nerves are sensory
  • Innervate the mucosa of the posterior one-third of the tongue
    
    • starting from the terminal sulcus of the tongue, and up to the epiglottis.
  • Besides this, these branches carry the afferent gustatory fibers afrom the lingual papillae and therefore are in charge of the reception impulses about the taste.

Vagus Nerve (Cranial Nerve X)

• Motor and a sensory nerve.

Vagus Nerve Nuclei

(1) Ncl. ambiguus: main motor nucleus (3rd pharyngeal branch)

• AF: corticonuclear fibers from both cerebral hemispheres.
• EF: fibers supply the constrictor muscles of the pharynx and the
• intrinsic muscles of the larynx

(2) Dorsal ncl of vagus n: the parasympathetic nucleus (VM)

• Lies beneath the floor of the lower part of the fourth ventricle posterolateral to the hypoglossal nucleus
• AF:
  
  • Fibers from the hypothalamus through the descending autonomic pathways.
  • From the glossopharyngeal nerve (carotid sinus reflex).
• EF:
  
  • Fibers are distributed to the involuntary muscle of the bronchi, heart, esophagus, stomach, small intestine, and large intestine as far as the distal one-third of the transverse colon

(3) Ncl of solitary tract (VS)

• Lower part of the nucleus of the tractus solitarius.
• AF: from visceral organs, as well as taste information.
• Gustatory ncl: rostral part of ncl of solitary tract
  
  • Sensations of taste travel through the peripheral axons of nerve cells situated in the inferior ganglion on the vagus nerve.
    
    • ​Epiglottis, epiglottic valeculae, part of roof of tounge
• EF: fibers cross the median plane and ascend to the ventral group of nuclei of the opposite thalamus as well as to a number of hypothalamic nuclei. From the thalamus, the axons of the thalamic cells pass through the internal capsule and corona radiata to end in the postcentral gyrus.

Spinal ncl of trigeminal nerve

• Afferents that converge on the spinal trigeminal nucleus:
  
  • Relay sensory information regarding pain, temperature and deep touch of:
    
    • the outer ear, the dura of the posterior cranial fossa and the mucosa of the larynx.
• through the superior ganglion of the vagus nerve but ends in the spinal nucleus of the trigeminal nerve.

Course of the Vagus Nerve

Exits the brain from the medulla oblongata of the brainstem→ Specifically, the nerves emerge by a series of rootlets between the olive, or the olivary body, and the inferior cerebellar peduncle→ travels laterally exiting the skull through the jugular foramen→ The sensory ganglia of the the vagus nerve consists of a superior and inferior ganglionic swelling →The vagus nerve is joined by the cranial root of the accessory nerve (CN XI), just after this inferior ganglion.

The vagus nerve trunk subsequently passes down the neck between the carotid artery and the internal jugular vein, within the carotid sheath. At the base of the neck, the nerve enters the thorax, however, the right and left vagus nerve take different paths after this point. The left vagus nerve travels anterior to the aortic arch, behind the primary left bronchus and into the esophagus. The right vagus nerve travels behind the esophagus and primary right bronchus.

Both left and right vagus nerves subsequently enter the abdomen through the esophageal hiatus of the diaphragm and follow their own individual path to their terminal branches.

• Leaves the anterolateral surface of the upper part of the medulla oblongata as a series of rootlets in a groove between the olive and the inferior cerebellar peduncle→ jugular foramen.
• The vagus nerve possesses two sensory ganglia
  
  • Rounded superior ganglion
    
    • ​situated on the nerve within the jugular foramen,
  • Cylindrical inferior ganglion,
    
    • which lies on the nerve just below the foramen.
    • Below the inferior ganglion, the cranial root of the accessory nerve joins the vagus nerve and is distributed mainly in its pharyngeal and recurrent laryngeal branches.
• The vagus nerve descends vertically in the neck: within the carotid sheath with the internal jugular vein and the internal and common carotid arteries.
  
  • Right vagus nerve
    
    • Enters the thorax and passes posterior to the root of the right lung: contributing to the pulmonary plexus.
    • It then passes on to the posterior surface of the esophagus and contributes to the esophageal plexus.
    • It enters the abdomen through the esophageal opening of the diaphragm.
    • The posterior vagal trunk (which is the name now given to the right vagus) is distributed to the
      
      • posterior surface of the stomach and,
      • by a large celiac branch, to the duodenum, liver, kidneys, and small and large intestines as far as the distal third of the transverse colon.
      • This wide distribution is accomplished through the celiac, superior mesenteric, and renal plexuses.
  • The left vagus nerve
    
    • ​Enters the thorax and crosses the left side of the aortic arch and
    • Descends behind the root of the left lung, contributing to the pulmonary plexus.
    • Descends on the anterior surface of the esophagus, contributing to the esophageal plexus.
    • It enters the abdomen through the esophageal opening of the diaphragm.
    • The anterior vagal trunk (which is the name now given to the left vagus) divides into several branches, which are distributed to
      
      • the stomach, liver, upper part of the duodenum, and head of the pancreas.

Branches of the vagus nerve

1- Branches in the jugular fossa

• The meningeal branch
  
  • Arises at the at the superior ganglion
  • Re-enters the skull at the jugular foramen.
  • SS: dura of the posterior cranial fossa (→spinal ncl V)
• The auricular branch
  
  • Also referred to as Arnold’s Nerve,
  • Arises from the superior ganglion
  • Re-enters the lateral portion of the jugular foramen via the mastoid canaliculus.
  • Exits again through the tympanomastoid suture of the temporal bone→ to reach and supply the skin.
  • SS: it innervates and supplies sensation to the the external tympanic membrane and a small portion of the posterior aspect of the external ear.

2-Branches in the neck

• The pharyngeal nerve
  
  • Arise from the inferior ganglion of the vagus nerve
  • Contain: VS and SM
  • SM: supplied by the accessory nerve (CN XI) which joins the pharyngeal nerve.
    
    • Passes across the internal carotid artery →to the middle pharyngeal constrictor muscle → Here, filaments of the pharyngeal branches form a plexus along with:
      
      • Branches of the glossopharyngeal (CN IX) nerve,
      • Branches of the external laryngeal nerve and sympathetic fibers from the superior cervical ganglion.
      • This is called the pharyngeal plexus, which supplies the:
        
        • Pharyngeal muscles (excl. the stylopharyngeus muscle),
        • Mucous membrane of the pharynx (excl. the stylopharyngeus muscle)
        • Soft palate (excl. tensor palatini muscle).
  • VS: contribute to the internal carotid plexus (located on the lateral side of the internal carotid artery) along with sympathetic and glossopharyngeal fibers.
    
    • The vagal visceral afferent fibers are responsible for transmitting impulses from the chemoreceptors in the carotid body.
    • As the vagus nerve descends down the carotid sheath, it inter communicates with the filaments or branches of the cervical sympathetic trunk, and so from the neck downward it is considered a mixed parasympathetic-sympathetic nerve.

Superior laryngeal nerve

• Structure of IV branchial arch
  
  • Innervates the pharyngeal and laryngeal derivatives of this arch.
• AF: arise from the inferior ganglion of the vagus nerve.
• This branch receives some sympathetic fibers from the superior cervical ganglion.
• At the level crossing of the hypoglossal nerve (CN XII), the superior laryngeal nerve passes between the external and internal carotid arteries.
• It then divides into external and internal branches at the tip of the hyoid bone, which lies under the mandible.
• The internal laryngeal branch enters the larynx through the thyrohyoid membrane and it supplies most of the mucosa above the glottis.
• The external laryngeal branch travels to the inferior pharyngeal constrictor muscle. This branch innervates an intrinsic laryngeal muscle called the cricothyroid muscle. All other intrinsic laryngeal muscles are innervated by the recurrent laryngeal nerve, which is another branch of the vagus nerve, discussed below.

Recurrent laryngeal nerve

Also known as the inferior laryngeal nerves, there are two recurrent laryngeal nerves, one on the right side of the body and one on the left. They were appropriately given the name recurrent laryngeal nerves as they follow a recurrent course and travel in the opposite direction to the nerve they branched from. The recurrent laryngeal nerve contains branchial efferent fibers.

Question 19

Accessory and hypoglossal nerves

Question 20

Cervical and thoracic sympathetic system

→

Cillary GGL: short cillary nn.

GGL: between optic n. and lat. rectus m. in apex of orbit

Parasympathetic:

Edinger westphal ncl→ CN III→ cavernous sinus →sup. orbital fissure→ orbit→ (branch to cillary ggl, III)

GGL:→ synapse

→ cillary m.: accomidation

→sphincter pupilae m: miosis (constricted pupil)

Sympathetic

superior cervical ggl→ Internal carotid plx→ optic canal→ opthalmic plx→ optic canal→

GGL

Dialator pupilae m: mydriasis (dialation)

superior and inferior branch III: superior and inferior tarsal m.

Sensory

V/1 (opthalmic n.)→ nasocillary n. (one of 3 branchs: lacrimal, frontal, nasicillary)→ communicating branch with cillary ggl

GGL

Sensory innervation of cornea

Pterygopalatine GGL

n. intermedius =Superior salivatory ncl (VM)+ ncl. gustatorius (part of ncl of solitary tract V)+spinal ncl of trigeminal nerve (SS)→Geniculate ggl

Parasympathetic

Superior salivatory ncl→ (n. intermedius) VII→geniculate ggl→ greater petrosal n→ n. pterygoid canal

GGL

pharyngeal r→ nasapharyngeal gland

posterior nasal rr. →sphenopalatine f.→nasal glands

G/L palatine nn→ palatine canals → palatine glands ????

(Maxillary branch:) zygomatic n. →inferior orbital fissure→communicating branch to lacrimal gland→ lacrimal gland

(lacrimal n.- V/1)

Sympathetic

superior cervical ggl→ internal carotid plx→ optic canal→ deep petrosal n.→ pterygoid canal: n of pterygoid canal→

GGL→

inferior orbital fissure→ orbital rr

and to all the branchs of the parasympathetic system

Submandibular GGL

Parasympathetic

Superior salivatory ncl→ (n. intermedius) VII→geniculate ggl→ chorda tympani→ internal accustic meatus→ canaliculus chorda tympani→tympanic plx??→ pterygotympanic fissure

GGL→

lingual n. →submandibular, sublingual, lingual gland

Sympathetic

superior cervical ggl →external carotid plx→ plx of facial a

GGL

lingual n.

Sensory

The Lingual nerve (LN) is a branch of the mandibular division of the trigeminal nerve(V3) that is responsible for general somatic afferent (sensory) innervation.

Otic GGL (in infratemporal fossa)

Parasympathetic

Inf. salivatory ncl→ IX glossopharyngeal n→ middle ear→ tympanic n→ tympanic canaliculus → tympanic plx (w/ facial n) →lesser petrosal n→ canal of lesser petrosal n→ oval foramen

GGL

communicating branch to auriculotemporal n: parotid gland

(mandibular nerve (V3))

communicating branch to bucal n: buccal gland

Sympathetic

External carotid pl→ plx of middle meningeal a→

GGL

same branchs

Sensory

V/3→ GGL→ buccal n, auricculotemporal n.

MOTOR:

Motor fibres for tensor veli palatini and tensor tympani VII pterygoideus medialis V

SACRAL PART:

intermediolateral ncl: sacral parasympathetic ncl in the lateral horns of the spinal cord

Answer 20

The autonomic nervous system contains three subsystems:

• Sympathetic nervous system
• Parasympathetic nervous system
  
  • which are usually in opposition
• Enteric nervous system

Functions:

ANS

• Controls and regulates the internal viscera
• Involuntary
• maintenance of homeostasis through the opposing functions of its two anatomically and functionally distinct divisions, the parasympathetic and sympathetic nervous systems.
• Both systems provide some degree of nervous input to a given tissue at all times and either increase/enhances or decrease/inhibits the activity of the innervated structure.

Sympathetic

While the sympathetic system is also important at rest, it is essential for preparing us for emergencies, in other words, for “fight-or-flight” responses.

The general sympathetic pathway can be simplified into the following components:

• preganglionic
• ganglionic
• postganglionic

1- The preganglionic components

• Preganglionic neurons located inside the spinal cord and their fibers (axons- which are called preganglionic fibers)
  
  • in the intermediolateral cell columns (ICLs) of the spinal cord
  • lateral horns of the gray matter of the thoracic (T1-12) and upper lumbar (L1-2 or 3) spinal cord segments
• Somatotopiccly arranged:
  
  • T1-6 cell bodies: innervate the head, upper limb and thoracic viscera.
  • T7-11: innervate the body wall and abdominal viscera,
  • T11-L2(3): innervate the lower limb and pelvic viscera.
• They travel very briefly through the anterior rami of spinal nerves T1-L2(3)→ white rami communicantes (white because nerve fibers are covered with white myelin)→passing to the sympathetic trunks through the
• The axons synapse with the postganglionic neuron inside sympathetic ganglia.
• These ganglia are actually a collection of cell bodies of postganglionic neurons, usually situated outside the CNS.

Ganglionic components

Types of ganglia

Paravertebral ganglia (“para” = alongside, beside)

• occur on either side of the vertebral column
• are independently linked on either side, forming two sympathetic trunks (chains).
• The site where preganglionic fibers synapse with postganglionic neurons.
• The trunks extend the entire length of the column, from the base of the cranium to the coccyx.
• They converge anteriorly to the coccyx, forming the ganglion impar (ganglion of Walther).
• Each trunk is attached to the anterior rami of the T1-L2(3) spinal nerves.

1- superior cervial ggl

• Lies below the base of the skull.
• postganglionic fibers:
  
  • Grey rami communicating rr.
  • Jugular n→ connects inf. ggl of glossopharyngeal n with inferior ggl of vagus n
    
    • functionally it sevres as a grey communicating branch composed of postggl fibers????
  • Internal carotid n→ cavernous sinus→internal carotid plx: splits into branchs of the internal carotis a
    
    • caroticotympanic n→into tympanic cavity
    • optic canal →
      
      • deep petrosal n→ fuses with great petrosal n. to form the n. of pterygoid canal→ into pterygopalatine ggl→
        
        • same branchs sympathetic
          
          • pharyngeal r→ nasapharyngeal gland
          • posterior nasal rr. →sphenopalatine f.→nasal glands
          • G/L palatine nn→ palatine canals → palatine glands ????
          • (Maxillary branch:) zygomatic n. →inferior orbital fissure→communicating branch to lacrimal gland→ lacrimal gland
        • inferior orbital fissure→ orbital rr
          
          • opthalmic plx:
            
            • → sympathetic root of cillary ggl- no synapse!
              
              • → short cillary n (the synapse is in the superior cervical ggl)
              • → orbital rr → superior and inf tarsal m.
  • External carotid n→ external carotid plx
    
    • plx of facial a→ sympathetic root of submandibular ggl
      
      • →lingual n. →submandibular, sublingual, lingual gland
    • plx of middle meningeal a→ sympathetic root of otic ggl
      
      • →communicating branch to auriculotemporal n: parotid gland
      • →communicating branch to bucal n: buccal gland
    • branchs from carotid body
  • Laryngopharyngeal rr: joins the pharyngeal rr from IX and X to form pharyngeal plx
  • Superior cervical cardiac n.
    
    • Left: behind common carotid a
    • Right: behing BC trunk
    • →medastinum→ terminates in cardix plx

2- middle cervical ggl

• smallest and may be absent
• rr to thyroid plx
• subclavian ansa carotid plx
• cardiac plx

3-stellae/inferior cervial ggl

• The inferior cervical ganglion typically fuses with the first thoracic ganglion to form the stellate ganglion. Its postganglionic fibers form plexuses around the
• subclavian artery
• around the vertebral artery
• inferior cardia c (cardiac plx)

4- thoracic ggl

5- lumbar/abdominal ggl

6- sacral ggl

Prevertebral ganglia (splanchnic ganglia)

• Located in the abdominal cavity around the origin of the major branches of the abdominal aorta.
• Form aggregations around the abdominal prevertebral plexus
• Referred to as:
  
  • Celiac ganglia
  • Aorticorenal ganglia
  • Superior and inferior mesenteric ganglia.
• Various nerve plexuses branch from these ganglia.

2- Postganglionic components

• consist of postganglionic neurons and their fibers.
• The axons leave the ganglia and project onto visceral effectors, where they release the neurotransmitter norepinephrine.
• Both preganglionic and postganglionic neurons are multipolar.

Question 21

Cranial and sacral parasympathetic system

→

Answer 21

The autonomic nervous system contains three subsystems:

• Sympathetic nervous system
• Parasympathetic nervous system
  
  • which are usually in opposition
• Enteric nervous system

Functions:

ANS

• Controls and regulates the internal viscera
• Involuntary
• maintenance of homeostasis through the opposing functions of its two anatomically and functionally distinct divisions, the parasympathetic and sympathetic nervous systems.
• Both systems provide some degree of nervous input to a given tissue at all times and either increase/enhances or decrease/inhibits the activity of the innervated structure.

Parasympathetic fibres are sent to various viscera to ensure different involuntary functions, such as:

• Constriction of the pupil (protecting the pupil from excessive bright light)
• Contraction of the ciliary muscle, (allowing the lens to thicken for near vision e.g., accommodation)
• Promotion of the secretion of the lacrimal glands
• Promotion of abundant watery secretions of salivary glands, decreasing the rate and strength of contraction (conserving energy)
• Constriction of coronary vessels in relation to reduced demand
• Constriction of the bronchi (conserving energy)
• Promotion of bronchi mucus secretion of the lungs
• Sending impulses to induce peristalsis and secretion of digestive juices
• Contraction of the rectum during defecation
• Inhibition of the internal anal sphincter to cause defecation
• Promoting the building/conservation of glycogen
• Increases secretion of bile
• Inhibition of the contraction of internal sphincter of urinary bladder
• contraction of the detrusor muscle of the urinary bladder wall causing urination
• Stimulation of engorgement (erection) of erectile tissues of the external genitals

Sympathetic nervous system also innervates those structures in an antagonistic way.

Regardless of the extensive influence of its cranial outflow, the parasympathetic system is much more restricted than the sympathetic system in its distribution. The parasympathetic system distributes only to:

• The head.
• Viscera cavities of the trunk.
• Erectile tissues of the external genitalia.

Parasympathetic nervous system: craniosacral division,

• Its presynaptic neuron cell bodies located in two regions within the central nervous system (CNS), and their fibres exciting by two routes.
  
  • MO: cranial half of the system
  • Sacral segment of the spinal cord: sacral half of the system

Cranial part:

• In the gray matter of the medulla, the fibres exit the CNS within the following cranial nerves (CN)
• The associated cranial nerves form the cranial preganglionic parasympathetic fibres or what is known as the cranial parasympathetic outflow
  
  • CN III (oculomotor nerve)
  • CN VII (facial nerve)
  • CN IX (glossopharyngeal nerve)
  • CN X (vagus nerve)
    
    • 75% of all parasympathetic fibres
• Project to ganglia very close, or attached, to the target organ and makes a synapse.

Sacral part:

• The presynaptic parasympathetic neuron cell bodies of the sacral half of the system lie within the gray matter of the sacral segments (S2 – S4) of the spinal cord.
  
  • Leave the spinal cord through the anterior roots of the sacral spinal nerves S2 – S4 and the pelvic splanchnic nerves that arise from their anterior branches.
  • They join together, after exiting the spinal cord, to form the pelvic nerves and mainly innervate the viscera of the pelvic cavity.
• Parasympathetic synapses use the neurotransmitter acetylcholine, and are called cholinergic pathways.

Parasympatetic Ganglia

• They occur in
  
  • the dorsal roots of spinal nerves,
  • in the sensory roots of CN:
    
    • the trigeminal,
    • facial,
    • glossopharyngeal,
    • vagal
    • vestibulocochlear cranial nerves
  • In autonomic nerves and in the enteric nervous system.
• Each ganglion is enclosed within a capsule of fibrous connective tissue and contains neuronal somata and neuronal processes.
• Some ganglia, particularly in the autonomic nervous system (ANS), contain fibres from cell bodies that lie elsewhere in the nervous system and that either pass through, or terminate within, the ganglia.

The parasympathetic ganglia of the head and neck are:

• Ciliary ganglion
• Pterygopalatine ganglion
• Submandibular ganglion
• Otic ganglion

Cillary GGL: short cillary nn.

• GGL: between optic n. and lat. rectus m. in apex of orbit
• Parasympathetic:
  
  • Edinger westphal ncl→ CN III→ cavernous sinus →sup. orbital fissure→ orbit→ (branch to cillary ggl, III)
  • GGL:→ synapse
  • → cillary m.: accomidation
  • →sphincter pupilae m: miosis (constricted pupil)
• Sympathetic
  
  • superior cervical ggl→ Internal carotid plx→ optic canal→ opthalmic plx→ optic canal→
  • GGL
  • Dialator pupilae m: mydriasis (dialation)
  • superior and inferior branch III: superior and inferior tarsal m.
• Sensory
  
  • V/1 (opthalmic n.)→ nasocillary n. (one of 3 branchs: lacrimal, frontal, nasicillary)→ communicating branch with cillary ggl
  • GGL
  • Sensory innervation of cornea

Pterygopalatine GGL

n. intermedius =Superior salivatory ncl (VM)+ ncl. gustatorius (part of ncl of solitary tract V)+spinal ncl of trigeminal nerve (SS)→Geniculate ggl

• Parasympathetic
  
  • Superior salivatory ncl→ (n. intermedius) VII→geniculate ggl→ greater petrosal n→ n. pterygoid canal
  • GGL
  • pharyngeal r→ nasapharyngeal gland
  • posterior nasal rr. →sphenopalatine f.→nasal glands
  • G/L palatine nn→ palatine canals → palatine glands ????
  • (Maxillary branch:) zygomatic n. →inferior orbital fissure→communicating branch to lacrimal gland→ lacrimal gland
    
    • (lacrimal n.- V/1)
• Sympathetic
  
  • superior cervical ggl→ internal carotid plx→ optic canal→ deep petrosal n.→ pterygoid canal: n of pterygoid canal→
  • GGL→
  • inferior orbital fissure→ orbital rr
    
    • and to all the branchs of the parasympathetic system

Submandibular GGL

• Parasympathetic
  
  • Superior salivatory ncl→ (n. intermedius) VII→geniculate ggl→ chorda tympani→ internal accustic meatus→ canaliculus chorda tympani→tympanic plx??→ pterygotympanic fissure
  • GGL→
  • lingual n. →submandibular, sublingual, lingual gland
• Sympathetic
  
  • superior cervical ggl →external carotid plx→ plx of facial a
  • GGL
  • lingual n.
• Sensory
  
  • The Lingual nerve (LN) is a branch of the mandibular division of the trigeminal nerve(V3) that is responsible for general somatic afferent (sensory) innervation.

Otic GGL (in infratemporal fossa)

• Parasympathetic
  
  • Inf. salivatory ncl→ IX glossopharyngeal n→ middle ear→ tympanic n→ tympanic canaliculus → tympanic plx (w/ facial n) →lesser petrosal n→ canal of lesser petrosal n→ oval foramen
  • GGL
  • communicating branch to auriculotemporal n: parotid gland
    
    • (mandibular nerve (V3))
  • communicating branch to bucal n: buccal gland
• Sympathetic
  
  • External carotid pl→ plx of middle meningeal a→
  • GGL
  • same branchs
• Sensory
  
  • V/3→ GGL→ buccal n, auricculotemporal n.
• MOTOR:
  
  • Motor fibres for tensor veli palatini and tensor tympani VII pterygoideus medialis V

SACRAL PART:

• intermediolateral ncl: sacral parasympathetic ncl in the lateral horns of the spinal cord
• sacral splanchnic nerves
  
  • pre-ggl fibers

Question 22

Abdominal and pelvic autonomic plexuses and ganglias, enteric system