• vertebra develop in mesoderm
• notochord guides development of vertebral column and spinal cord --> gives rise to nucleus pulposis of IVD
• condensations of mesoderm around notochord called somites are formed

• Develops:

1. sclerotome -  from which vertebral coloumn develops(cartilage and bone)
2. myotome - from which muscle develops
3. dermatome - from which peripheral nerves develop (skin innervation)

• gives rise to all neurons and supporting cells
• forms neural plate (neuroectoderm)

1. Notochord
2. Ectoderm
3. Neural Plate

1. Macroglial cells
• Oligodendrocytes
• Astrocytes
2. Neurons CNS
3. Ependymal Cells
4. Retinal cells

Don't be a MOANER about what your mom puts on your plate

• composed of cells derived from mesoderm, and is found ventral to neural tube
• induces ectoderm to form neuroectoderm 
• remnant as nucleus pulposus of IVD

sheet of ectodermal cells with neural properties

• begins to fold and forms neural groove
• further folds to form neural tube (rostral end develops into spinal cord, cephalad end develops into brain)

• forms the lining of digestive tube and its assoc. structures
• division foregut/midgut: liver and pancreatic buds

1. Foregut (supplied by Celiac trunk)
• esophagus, stomach, proximal half of duodenum
2. Midgut (supplied by superior mesenteric A.)
• Distal half of Duodenum, Jejunum, Ileum, Ascending Colon, Proximal 2/3 of transverse colon
3. Hindgut (supplied by Inferior mesenteric A.)
• Distal 1/3 of transverse colon, descending colon, sigmoid colon, and rectum 

Allantois (*?*)

• Urinary bladder, vagina, urethra, prostate and urethral glands

C1 - none

C2 - scalp

C3 - nape of neck

C4 - shoulder

C5 - deltoid

C6 - 6 shooter

C7 - middle finger

C8 - pinky to medial forearm

T1 - medial elbow

T2 - under arm (axilla)

T4 - nipple line

T7 - zyphoid 

T10 - umbilicus

L1 - Inguinal

L2 - anterior thigh

L3 - lateral thigh cross at knee

L4 - (to floor) medial leg and big toe

L5 - lateral leg and top (dorsum) of foot 

S1 - lateral foot, posterior calf

S2 - posterior thigh

S3 - big circle around anus

S4 - little circle around anus

S5 - anus

gives rise to astrocytes and oligodendrocytes; (glue) c/t in brain

Glio = Glue

1. Ependymal cells
2. Oligodendrocytes
3. Astrocytes
4. Schwann cells

Neuroglial cells

• most numerous cell of CNS
• acts like c.t.
• part of BBB
• forms "scar like" tissue in injury

• innermost layer of neural tube
• ciliated cell that lines ventricles
• makes "leaky" barrier b/w CSF and CNS
• produces CSF

1. Oligodendrocyte - forms myelin around CNS
2. Schwann cell - forms myelin around PNS

COPS

• derived from mesoderm, phagocytes (macrophages) of the nervous sys
• not many

• "connector" neurons w/in CNS

1. Commissural - b/w two hemispheres
2. Association - from differant parts of same hemisphere
3. Projection - from lower centers to cerebral cortex

Connectors on a CAP 

CNS - brain & spinal cord 

1. Gray matter - cell bodies and dendrites
2. White matter - myelinated axons
3. Macroglia

• astrocytes - BBB (fncs as active transport for glucose and filters)
• oligodendrocytes - produce myelin

PRIMARY

SECONDARY

1. Prosencephalon

• Telencephalon (forebrain)
• Diencephalon (thalamus, hypothal. pineal, retina, mammilary bodies, posterior pituitary)

1. Mesencephalon

• Mesencephalon (midbrain)

1. Rhombencephalon

• Metencephalon (Pons & Cerebellum)
• Myelencephalon (Medulla oblongata)

Telencephalon (CN I)

• Neural canal regions: Lateral ventricles separated by septum pellucidum

Diencephalon (CN II)

• Foramen of Monroe (AKA Interventricular foramen) = Lateral ventricles to 3rd ventricle; 3rd ventricle

Mesencephalon (CN III, IV)

• Cerebral Aqueduct of Sylvius

Metencephalon (CN V, VI, VII, VIII)

• 4th ventricle

Myelencephalon (CN IX, X, XI, XII)

• 4th ventricle

• 2 Lateral aperatures --> Foramina of Luschka
• 1 Median aperature --> Foramen of Magendie

These foramina allow the exit of CSF from 4th ventricle to the subarachnoid space of the spinal cord.

Lateral = Luschka

Median = Magendie

1. Blood supply communication b/w forebrain and hindbrain.
2. Anatomically around pituitary gland & optic chiasm.
3. Internal carotid A's & vertebral A's supply circle
4. Anterior cerebral A. & Posterior cerebral A, Anterior communicating A. & posterior communicating A make circle

Most common location for "cerebral vascular accident" (CVA)

• Carries more blood than the other arteries (~800mL/min)

AKA Anterior Spinal A.

• Sends 200 branches into ventral (ant.) aspect of cord

AKA Posterior Spinal A. (2 of them)

• branches provide blood to posterior roots of spinal cord

AKA Pallium, developed from the neural plate

1. Neocortex - (AKA isocortex) 90% of cortex
• Six cerebral cortex laminae (mostly synaptic activity)
2. Allocortex - 10% of cortex

mostly formed by thalamus

1. relay for cortex, processes sensory information, sleep, consciousness
2. motor relay

1. Responsible for postural adjustments, steadying voluntary movments, enkephalins (nociception regulators)
2. Striatal lesions - tremors (ie. Parkinson's, Huntington's chorea, ballism)
3. Surrounds thalamus
4. Includes - caudate nucleus, putamen, globus pallidus, amygdaloid nucleus & claustrum

Striatum or neostriatum - caudate nucleus & putamen

Lentiform nucleus - putamen & globus pallidus

Corpus striatum (AKA striate body)- caudate nucleus & lentiform nucleus

• Corpus striatum (caudate nucleus, lentiform nucleus)
• Thalamus
• Subthalamic nucleus
• Substantia Nigra
• Pedunculopontine nucleus (midbrain)

1. Made up of midbrain, pons & medulla oblongata
2. Conduit for ascending & descending tracts
3. Contains reflex centers associated with Respiration, Cardiovascular & Consciousness
4. Contains important nuclei of CN III-XII

• From inside-out - Pia mater, Arachnoid (spider) mater, Dura Mater 

PAD

• b/w arachnoid & pia mater 
• where they go for lumbar puncture or "spinal tap"

Total (adult) = 140-270 mL

 in Ventricles = ~25mL

1. Dorsal roots - sensory (afferent fibers)
2. Ventral roots - motor (efferent fibers)

SAME

• Basal ganglia

...striate body)

• Caudate nucleus & Lentiform nucleus

• Athetosis (slow "wormlike" movements; especially of fingers and hands)
• Chorea (quick movements)
• Hemiballismus (violent "throwing" movements of arm and leg)

1. Cerebral aqueduct of Sylvius
2. Cerebral peduncles
• crus cerebri (anterior portion)
3. Substantia nigra

• connects 3rd and 4th ventricles for CSF flow
• located in midbrain

• used to classify everything in midbrain except tectum 

1. cerebral tegmentum
2. pretectum (pretectal area)
3. crus cerebri

2 divisions:

• pars compacta --> Dopamine
• pars reticularis --> GABA

black color - dopamine, its from tyrosine, melanin is by product which causes dark color

• part of cerebral peduncle - contains Corticospinal, Corticopontine, Corticobulbar & Corticomesencephalic fibers (eye movement)

CC²

• processes input from other areas of the brain, spinal cord and sensory receptors to provide precise timing for coordinated, smooth movements of the skeletal muscular system

• made up of 3 lobes:

1. Anterior (paleocerebellum)
2. Posterior (neocerebellum)
3. Flocculonodular (Archicerebellum)

• Longitudinal zones
• vermis - midline
• 2 lateral hemispheres (AKA paravermal zone)

• Paleocerebellum (AKA spinocerebellum) - general muscle tone 

• Neocerebellum (AKA cerebrocerebellum) - coordination of skilled movements

     - receives information from cortex 

3 Major Arteries:

• Superior Cerebellar A. (basilar A.)
• Anterior Inferior Cerebellar A. (basilar A.)
• Posterior Inferior Cerebella A. (vertebral A.)

Branches of vertebral & basilar arteries

[image]

• Purkinje 
• Golgi II
• Stellate
• Basket
• Granular

• From medial to lateral (small to large):
• Fastigial
• Globus
• Emboliform
• Dentate

Flowers Grow Every Day

Crude sensation & integrations

"Relay center"

UMNL vs. LMNL

(DTR, Muscle tone, pathological reflexes, superficial reflexes)

UMNL

• dec. DTR
• inc. Muscle tone
• + pathological reflexes (ie babinski)
• Spasticity
• Hypertrophy
• Clonus
• dec. superficial reflexes (bilateral)

LMNL

• dec. DTR
• dec. muscle tone
• NO pathological reflexes
• Flaccidity
• Atrophy
• Fasciculations
• dec. superficial reflexes (unilateral)

• Dorsal Columns (Fasciculas Cuneatus & Gracilis) - Discriminative (2pt) touch, Vibration & Conscious Proprioception
• Dorsal (posterior) Spinocerebellar - Unconscious Proprioception
• Ventral (anterior) Spinocerebellar - Unconscious Proprioception
• Lateral spinothalamic - Pain & Temperature
• Anterior (ventral) spinothalamic - "Protopathic", is defensive to pain, temperature, crude light touch
• Spinotectal - Spino visual reflexes
• Spinoreticular - Levels of consciousness

Fasiculus cuneatus (above T6) & gracilis (below T6)

Pathway

1. Posterior (dorsal) root ganglion
2. Nuclei gracilis/cuneatus (2nd order neurons are called internal arcuate fibers)
3. Posteriolateral nucleus (PLN) of thalamus --> post central gyrus

Diabetes mellitus, Posteriolateral sclerosis (PLS), Multiple sclerosis & Tabes dorsalis (syphilis) all affect dorsal columns

Pathways

1. Posterior root ganglion
2. Nucleus dorsalis (AKA Clark's collumn) - ascend through inferior cerebellar peduncle to cerebellum.

Clark's collumn (C8-L4)

"PI" --> Posterior Inferior Peducle

Pathways

1. Posterior (dorsal) root ganglion
2. Substantia gelatinosa (apex of posterior horn)
3. Posterior lateral nucleus (PLN) of thalamus --> postcentral gyrus

Incoming nerve branches 1-2 segments up & down (Tract of Lissauer)

Main neurotransmitter (NT) of 1st order --> Substance P

"Syringomyelia" - fluid filled cyst leads to cape-like (bilateral) loss of pain & temperature

Pathways

1. Posterior root ganglion
2. Substantia gelatinosa
3. Posterior lateral nucleus (PLN) of thalamus --> postcentral gyrus

"Tactile sensation"

..Spino-quadrigeminal system of Mott)

Pathway

1. Posterior root ganglion
2. Cross segmentally & ascend to superior colliculus (midbrain)

Movements of eyes & head toward stimulus

Pathways

1. Posterior root ganglion
2. Ascend to nuclei of reticular formation (brainstem)

If damaged, coma will be present

• Corticospinal (Lateral & Anterior) - precise & skilled voluntary movement (ie. threading needle or writing)
• Rubrospinal - fascilitates flexors & inhibits extensors
• Reticulospinal - inhibit or facilitate voluntary movement
• Vestibulospinal - facilitates extensors & inhibits flexors
• Tectospinal - reflex postural movement to visual stimuli

... Pyramidal tract)

Pathway

1. 1st motor cortex (AKA M1; primary motor and lateral motor cortex), 2nd motor cortex (AKA M2; supplement motor area), and parietal lobe
2. Internuncial neurons (connecting neuron) or alpha motor neurons 

Most cross at decussation of pyramids & descend as lateral corticospinal (some continue as Anterior (ventral) corticospinal tract

Lateral - length of cord

Anterior - stops mid-thoracic

Pathways

1. Red nucleus (midbrain - motor coordination)
2. Alpha & gamma motor neurons

Recieves cerebral & cerebellar information

..Extrapyramidal

Pathway

1. Reticular formation
2. Alpha & gamma motor neurons

Crosses at various locations

Pathway

1. Lateral vestibular nucleus
2. Alpha & gamma motor neurons

Recieves inner ear (via vestibular nerve) & cerebellar information

Pathway

1. Superior colliculus (midbrain)
2. Alpha & gamma motor neurons

Tecto Techno = visual stimuli

.. cranial & spinal nerves (and their ganglia)

*Cranial nerves (except CN 2)

Group of neuron cell bodies

(Ganglia, Group)

• Cutaneous branches (superficial)
• Motor branches (deep)

1. Lesser Occipital
• C2,C3 
• Sensory - posterolateral neck
2. Greater Auricular 
• C2,C3 
• Sensory - ear & parotid gland
3. Transverse cervical
• C2,C3 
• Sensory - anterior & lateral neck
4. Supraclavicular (anterior, middle, & posterior)
• C3,C4 
• Sensory - shoulder & anterior chest

1. Ansa cervicalis 
• C1-C4
• Motor - geniohyoid & infrahyoid muscles of neck
2. Segmental branches (superior & inferior roots)
• C1-C5
• Motor - neck & scalenes, levator scapulae, trapezius, SCM
3. Phrenic
• C3,C4,C5 - Keep the Diaphragm ALIVE!

1. Femoral
• L2-L4
2. Obturator
• L2-L4
3. Lateral Femoral Cutaneous
• L2,L3
4. Iliohypogastric
• L1
5. Ilioinguinal
• L1
6. Genitofemoral
• L1,L2

(lumbar plexus)

L2-L4

• Sensory - Thigh, leg, foot hip, knee joints
• Motor - Anterior thigh, psoas, pectineus, iliacus

1. Sciatic N.
• L4,L5,S1-S3
  
2. Tibial
• L4-S3
  
3. Common Peroneal (Fibular)
• L4-S2
  
4. Superficial Peroneal (Fibular)
• L4-S2
5. Deep Peroneal (Fibular)
• L4-S2
6. Superior Gluteal
• L4,L5,S1
  
7. Inferior gluteal
• L5-S2
  
8. Pudendal
• S2-S4
  

(Sacral plexus)

L4-S3

• Motor - Tibial & Common Peroneal

• Roots
• Trunks
• Divisions
• Cords
• Branches

Randy Travis Drinks Cold Beer

1. C5 Root
2. C6 Root
3. C7 Root
4. C8 Root
5. T1 Root

1. Upper Trunk (C5,C6)
2. Middle Trunk (C7)
3. Lower Trunk (C8,T1)

1. Anterior Division
• anterior division of upper, middle and lower trunk
2. Posterior Division
• posterior division of upper, middle and lower trunk

6 total

1. Lateral Cord
• from anterior divisions of upper and middle trunks (C5,C6,C7)
2. Posterior Cord
• from all posterior division (C5,C6,C7,C8,T1)
3. Medial Cord 
• from lower trunk, anterior division (C8,T1)

1. Musculocutaneous (C5,C6,C7)
• supplies Biceps, Brachialis, Coracobrachilalis muscles & skin of lateral forearm (BBC muscle)
2. Axillary (C5,C6) 
• supplies Deltoid, Teres Minor muscles & skin over deltoid
3. Radial (C5,C6,C7,C8,T1)
• supplies Triceps, Brachioradialis, all Extensors of wrist, Abductors of thumb, & Supinator muscles (BEAST nerve)
4. Median (C5,C6,C7,C8,T1)
• supplies all forearm muscles (except flexor carpi ulnaris & ulnar half of flexor digitorum profundus) & LOAF thumb muscles
5. Ulnar (C8,T1)
• supplies all intrinsic muscles of hand (except LOAF thumb muscles)

1. Sympathetic
2. Parasympathetic

• Axons include: T₁ - L₁/L₂
• Short Preganglionic: Neurotransmitter  - ACh (Acetylcholine)
• Long Postganglionic: Neurotramsmitter - Epinephrine & Norepinephrine

• Axons include: CN's III, VII, IX, X; Sacral - S₂-S₄
• Long Preganglionic: Neurotransmitter  - ACh (Acetylcholine)
• Short Postganglionic: Neurotramsmitter - ACh (Acetylcholine)

... Involuntary structures such as:

• Heart
• Smooth Muscle
• Glands

• Coronal (frontal & parietal)
• Sagittal (2 parietals)
• Lambdoidal (parietal & occipital)
• Squamous (temporal & parietal)

CN I  - Cribiform plate

CN II - Optic Canal

CN III, IV, V₁, VI - SOF

CN V₂ - Foramen rotundum

CN V₃ - Foramen ovale

CN VII, VIII - Internal Auditory Meatus

CN IX, X, XI - Jugular Foramen

CN XII - Hypoglossal

Cribiform plate (inferiorly) & Crista galli (superiorly)

3 primary (completed by 3-6 yo)

• body (aka centrum)
• right & left neural arch

 5 secondary (completed by 25 yo)

• SP
• Right & Left TP
• Upper & Lower vertebral endplates

Lumbars have 2 additional ossification centers for Mamillary processes

Top to bottom

•  Enamel --> Dentin --> Pulp (nerves & vessels) --> Cementum --> Root

Teeth by age:

3 yo...

Adult...

3 yo = 20 teeth

Adult = 32 teeth

• 12 pair
• Flat bones 

...Gladiolus)

 3 parts:

• Manubrium
• Jugular notch (aka suprasternal notch) - location anterior T3-4 vertebra
• Angle of Louis - manubrium/body meet, 2nd rib attachment
• Body - located T5-9, costal notches form lateral border
• Xiphoid process
• Xiphisternal cartilaginous joint
• Landmark diaphragm, diaphragmatic surface liver, inferior border of heart

... 5 fused vertebra (fuse by 25 yo)

• Base 
• sacral promontory
• Ala - lateral sides (aka "wings")
• Sacral foramina 
• branches of sacral spinal nerves pass through
• Apex 
• articulates w/ coccyx

C₃ - Hyoid Bone

C₄ - Cornu of thyroid

C₅ - Body of thyroid

C₆ - Cricoid cartilage & Carotid tubercle

• Anterior - Posteriolateral aspect of bodies and IVD
• Posterior - Anterior aspect of facet joint & capsule
• Superior - Inferior pedicle of vertebra above
• Inferior - Superior pedicle of vertebra below

• Cervical - rectangular body, bifid SP, uncinate processes, transverse foramina in TP which possess ant. & post. tubercles
• Thoracic - Heart-shaped body, sloping SP, costal facets on body & TP
• Lumbar- Kidney-shaped body, quadrangular SP, contains mammillary & accessory processes

• Cervical - face backwards, upwards & medially in horizontal plane (BUM)
• Thoracic - facets face backwards, upwards & lateraly in coronal plane (BUL)
• Lumbar - facets face backwards & medially in sagittal plane (BM)

• Axis also called Epistropheas
• 9 atypical vertebra in adults
• C2-C6 known as "Joints of Luska"
• C6 is lowest level of Vertebral A.

• Face & tongue
1. Orbicularis oculi
2. Zygomaticus (major)
3. Mentalis
4. Orbicularis oris
5. Buccinator
6. Genioglossus
7. Hyoglossus
8. Styloglossus
• Mastication
1. Temporalis
2. Masseter
3. Medial pterygoid (internal)
4. Lateral pterygoid (external)
• Superficial neck
1. Platysma
2. Sternocleidomastoid
• Suprahyoid
1. Digastric (2 bellies)
2. Stylohyoid
3. Mylohyoid
4. Geniohyoid
• Infrahyoid
1. Sternohyoid
2. Sternothyroid
3. Omohyoid (2 bellies)
4. Thyrohyoid
• Vertebral
1. Longus Colli
2. Scalenus Ant.
3. Scalenus Medius
4. Scalenus Post.

1. Orbicularis oculi
• Innervation - CN VII
• Action - eyelid sphincter
• Origin/Insertion - medial orbital margin/skin around margin of orbit
2. Zygomaticus (major)
• Innervation- CN VII
• Action - pull corner of mouth superiorly & laterally
• Origin/Insertion - Zygomatic bone/skin at corner of mouth
• Extra - laughing muscle
3. Mentalis
• Innervation- CN VII
• Action - elevates & protrudes lower lip
• Origin/insertion - Mandible / skin of chin
• Extra - doubt/disdain 
4. Orbicularis oris
• Innervation- CN VII
• Action - compresses & protrudes lips (oral sphincter)
• Origin/insertion - deep skin:Sup (maxilla), Inf (mandible)/ mucous membrane of lips
5. Buccinator
• Innervation- CN VII
• Action - compress checks
• Origin/insertion - mandible / orbicularis oris
• Extra - expels air, aides in mastication
6. Genioglossus 
• Innervation- CN XII
• Action - protrudes tongue
• Origin/Insertion - mental spine of mandible / dorsum of tongue & hyoid bone
7. Hyoglossus
• Innervation- CN XII
• Action - depress tongue
• Origin/insertion - hyoid bone / sides of tongue
8. Styloglossus
• Innervation- CN XII
• Action - retracts tongue & elevates hyoid 
• Origin/insertion - styloid process/ hyoid bone

1. Temporalis
• Innervation - CN V
• Action - elevate & retract mandible
• Origin/insertion - temporal fossa/ coronoid process of mandible
2. Masseter
• Innervation - CN V
• Action - elevate & protrudes mandible
• Origin/insertion - zygomatic arch/ mandibular angle
• Extra - prime mover of jaw closure
3. Medial pterygoid (internal)
• Innervation- CN V
• Action - elevates mandible
• Origin/insertion - lateral pterygoid plate (process) & maxilla / mandibular angle
4. Lateral pterygoid (external)
• Innervation- CN V
• Action - protrudes mandible 
• Origin/insertion - greater wing of sphenoid & lateral pterygoid plate / TMJ & mandible respectively.

1. Platysma
• Innervation - CN VII
• Action - Depresses lower lip & mandible 
• Origin/insertion - Skin over lower neck & upper lateral thorax / mandible 
2. Sternocleidomastoid "Torticollis"
• Innervation - CN XI
• Action - Tilts head to same shoulder, turns to opposite shoulder
• Origin/insertion - 
• Sternal head - manubrium/ mastoid process & superior nuchal line
• Clavicular head - Clavicle / mastoid process & superior nuchal line

1. Digastic (2 bellies)
• innervation - CN V & VII
• Action - elevates hyoid bone & depresses mandible
• Origin/insertion - 
• ant belly - Mandible / hyoid body
• post. belly - mastoid process / hyoid body
2. Stylohyoid
• Innervation - CN VII
• Action - elevates & retracts hyoid bone
• Origin/insertion - Styloid process/ Hyoid bone
3. Mylohoid
• Innervation - CN V
• Action - Elevates hyoid & raises oral floor
• Origin/insertion - mandible/ hyoid bone
4. Geniohyoid
• Innervation - Ant. Rami of C₁ via CN XII
• Action - Elevates & protracts hyoid bone
• Origin/insertion - mandible/ hyoid bone

Infrahyoid "Depress"

(Head and Neck compartment)

"Strap muscles", Swallowing & speaking

1. Sternohyoid
• Innervation - Ansa cervicalis N. (C1,2,3)
• Action - Depresses hyoid & larynx
• Origin/insertion - manubrium / hyoid bone
2. Sternothyroid
• Innervation - Ansa cervicalis N. (C1,2,3)
• Action - Depresses hyoid & larynx
• Origin/insertion - manubrium / thyroid cartilage
3. Omohyoid (2 bellies)
• Innervation - Ansa cervicalis N. (C1,2,3)
• Action - Depresses hyoid & larynx
• Origin/insertion - Scapula (sup. border) / hyoid bone
4. Thyrohyoid
• Innervation - C₁ via CN XII
• Action - Depresses hyoid & elevates larynx
• Origin/insertion - Thyroid cartilage/ hyoid bone

1. Longus Colli 
• Innervation - Ant. Primary Rami (C₂-C₆)
• Action -
• Unilateral - tilts & rotates opp. side
• Bilateral - flexes cervical spine
• Origin/insertion - 
• Superior Oblique - C₃-C₅ ant. tubercles of TP / Ant. tubercle of atlas
• Vertical (intermediate) - C₅-T₃ anterior body / C₂-C₄ anterior body 
• Inferior Oblique - T₁-T₃ anterior body / C₅-C₆ anterior tubercles of TP
• Extra - Attaches to anterior tubercle of atlas
2. Scalenus Anterior
• Innervation - Ant. Primary Rami (C3-C8)
• Action
• Ribs mobile - elevates upper ribs
• Ribs fixed - Flexes neck (bilateral) or lateral bends to one side (unilateral)
• Origin/insertion  - TP's of cervicals/ first 2 ribs
3. Scalenus Medius
• innervation - Ant. Primary Rami (C3-C8)
• Action
• Ribs mobile - elevates upper ribs
• Ribs fixed - Flexes neck (bilateral) or lateral bends to one side (unilateral)
• Origin/insertion - TP's of cervicals/ first 2 ribs
4. Scalenus Posterior
• Innervation - Ant. Primary Rami (C3-C8)
• Action
• Ribs mobile - elevates upper ribs
• Ribs fixed - Flexes neck (bilateral) or lateral bends to one side (unilateral)
• Origin/insertion - TP's of cervicals/ first 2 ribs

Suboccipital Triangle

(boundaries, roof, floor, contents)

• Boundaries: RCPM (rectus capitis posterior major), Obliquus capitis superior, obliquus capitis inferior
• Roof: deep fascia covered by semispinalis capitis
• Floor: Posterior arch C₁ & posterior atlanto-occipital membrane
• Contents: Vertebral A., Suboccipital N. and Suboccipital veins
• Know which is A. & which is N. They may ask

1. Multifidus
2. Rotatores
3. Intertransversarii
4. Interspinalis
5. Iliocostalis
6. Longissimus
7. Spinalis

• Innervation - Spinal N. (Dorsal rami)
• Action 
• unilateral - Lateral bend same side, rotate opposite side
• bilateral - extends spine
• Origin/Insertion
• C2-sacrum (TP / SP skipping 2-4 vertebrae)

Interspinalis

(Deep back muscles)

Iliocostalis, Longissimus & Spinalis

I Love Spine (from lateral to medial)

1. External Intercostals
2. Internal intercostals
3. Transverse thoracic
4. Subcostalis

External Intercostals

(Muscles of Thorax)

• Innervation - Intercostal N. (T₁-T₁₁)
• Action - raise ribs (inspiration)
• Origin/insertion - Lower margin of top rib / upper margin of bottom rib (oblique fibers going lat to med)

1. External oblique
2. Internal oblique
3. Transverse Abdominus
4. Rectus Abdominus
5. Cremaster

• Innervation - Intercostal N. (T₇-T₁₁) & Subcostal N. (T₁₂)
• Action- Compresses abdomen, flexes trunk, forced expiration
• Origin/insertion - External lower 8 ribs (5-12) / Iliac crest, ASIS, pubic tubercle, & linea alba

1. Quadratus lumborum
2. Psoas Major
3. Psoas Minor

Quadratus Lumborum

(Muscles of Posterior Abdominal Wall)

1. Piriformis
2. Obturator internus

Piriformis

(Muscles of Lateral Pelvis Wall)

1. Pubococcygeus
2. Puborectalis
3. Iliococcygeus
4. Coccygeus

Pubococcygeus

(Muscles of the Pelvic Floor)

1. Sphincter urethrae
2. Deep transversus perinei

Sphincter urethrae

[Muscles of the Urogenital Diaphragm (Deep perineum)]

1. Ischiocavernosus
2. Bulbospongiosus
3. Superficial transversus Perinei

Ischiocavernosus

(Muscles of Superficial Perineum)

Gustation

1. Circum"vallate" papillae:
• cylindrical, largest, least in #, bitter receptor 
• 8-12 in V-shaped form, anterior to sulcus terminalis
2. Fungiform papillae:
• Mushroom shaped, most numerous, tip of tongue
3. Foliate papillae:
• Posterior roof/mouth lateral margins
4. Filliform papillae:
• Thread-like, sensitive to touch (no taste)

• Tongue
• Anterior 2/3 - sweat, sour, salty
• CN VII --> Chorda tympani --> ptergopalatine --> Solitary tract & nucleus
• Posterior 1/3 - bitter
• CN IX
• Epiglottis & larynx - bitter
• CN IX

Embryonic thyroid diverticulum

(dorsal depression of tongue)

1. Olfactory bulb - limbic area
• contains granular, mitral & tufted cells, and a glomerulus
2. Nerve supply
• CN I to cribiform plate (ethmoid bone) --> lateral olfactory stria --> Uncus (medial olfactory stria) --> subcallosal gyrus
3. Pseudostratified columnar epithelium - upper surface of superior concha (main chemoreceptor)

I smell a skuncus in my uncus!

1. Retinal cells - Amacrine, bipolar, ganglion, horizontal, and pigments, rods & cones (rhodopsin)
2. Nerve supply 
• Retina --> CN II --> optic chiasm --> optic tract (connects superior colliculus) --> Lateral geniculate nucleus --> Optic radiations --> calcarine fissure of occipital lobe
3. Retina
• Fovea centralis - center of Macula Lutea; provides greatest acuity; only cones
• Optic disk - "Blind Spot" where optic N. & vessels attach to eye 
• Ciliary muscle - controls lens shape

• Nerve Supply
• Spiral ganglion --> cochlear N. --> ventral then dorsal cochlear nucleus --> Lateral Lemniscus --> Inferior colliculus --> Medial Geniculate --> Temporal lobe 
• LIM
• Sound travels
• External auditory meatus --> Tempanic Membrane (ear drum) --> handle of Malleus --> head of Malleus --> Incus --> Stapes --> Oval Window --> Cochlea --> Round Window
• "MIS. OCR"

Auditory tube 

(AKA Eustachian tube)

Perilymph

• moves in response to vibrations from middle ear via the oval window
• as fluid moves, cochlear partition moves
• partition moves up and down & wave of displacement flows from base to apex

Color

Cone = Color

1. Scala media
2. Saccule
3. Utricle
4. Semicircular ducts

I - Olfactory

II - Optic

III - Occulomotor

IV - Trochlear

V - Trigeminal

VI - Abducens

VII - Facial

VIII - Vestibulocochlear

IX - Glossopharyngeal

X - Vagus

XI - Accesory 

XII - Hypoglossal

Olfactory N.

Sensory - Smell

Path/Foramen of Exit

• Cribriform Plate - "Smell baby crib"

Does NOT synapse w/ Thalamus (only CN that doesn't)

Optic N.

Abducens N.

Motor - LR₆

Path/Foramen of Exit

• SOF

CN I    - Some 

CN II   - Say 

CN III  - Marry 

CN IV  - Money 

CN V   - But 

CN VI  - My 

CN VII - Brother 

CN VIII - Says 

CN IX   - Big 

CN X    - Brains 

CN XI   - Matter 

CN XII  - Most!

• CN's III, VII, IX, X 

CN X (90% of body)

• CN - CN V_{3 (mandibular branch)}
• Muscle - Muscles of Mastication, Jaw closing muscles
• Bone - Mandible, Malleus, & Incus
• Cartilage - Meckel's cartilage

• CN - CN VII
• Muscle - Muscles of facial expression, Jaw opening muscles, Stylohyoid, Stapedius
• Bone - Stapes, Styloid
• Cartilage - Reichert's cartilage

• CN - CN IX 
• Muscle - Stylopharyngeus
• Bone - Cornu, Hyoid
• Cartilage - None

• CN - CN X (superior laryngeal)
• Muscle - Muscles of pharynx except Stylopharyngeus
• Bone - None
• Cartilage - Thyroid & cricoid cartilages

1. Anterior Longitudinal Ligament (ALL)
2. Posterior Longitudinal Ligament (PLL)
3. Ligamentum flava
4. Interspinous 
5. Supraspinous
6. Transverse ligament
7. Cruciform
8. Alar
9. Apical dental
10. Denticulate

Anterior Longitudinal Ligament

(ALL)

• down front of bodies (sacrum - base of occiput)
• Thicker & stronger than PLL
• Above C2 turns into Atlantoaxial/Atlantooccipital membrane

• Back of body (w/in spinal canal)
• Above C2 --> Tectorial membrane

..Yellow ligament)

• Lamina to lamina

• b/w SP's 
• thickest in lumbar

Supraspinous ligament

(SSL)

• From SP to SP (occipital to coccyx)
• Above C7 --> Ligamentum nuchae

• Holds dens on fovea dentis (anterior arch facet) of atlas 
• lies across posterior dens and connects to tubercles on medial lateral masses.

Cruciate (Cruciform) ligament

• Cross shaped ligament 
• consists of transverse ligament & longitudinal ligament arising from middle of transverse (connecting to C2 body & occiput)

....Check Ligament

• from superiolateral sides of dens to occiput 

• From tip of dens (apex) to occiput