ANAT 5010 - unit 2

what is located inside the vertebral column?

- spinal cord (CNS)

- spinal nerve roots (PNS)

- meninges

- CSF

- extradural fat

- arteries

- veins

what makes up the central nervous system?

brain and spinal cord

what makes up the peripheral nervous system?

- spinal nerves

- cranial nerves

- somatic nervous system (motor and sensory)

- visceral nervous system (ANS)

how many cervical, thoracic, lumbar, sacral, and coccygeal spinal nerves are there?

- cervical: 8

- thoracic: 12

- lumbar: 5

- sacral: 5

- coccygeal: 1

the ventral horn houses - neurons

motor

the dorsal horn houses - neurons

sensory

explain the motor (efferent) pathway from the ventral horn

1. motor cell bodies (in the ventral horn)

2. motor neuron sends axons out of the spinal cord, forming the ventral root

3. axon help form the spinal nerve

4. spinal nerve breaks into the DPR and VPR to reach skeletal muscle

explain the sensory (afferent) pathway with the dorsal horn

1. peripheral receptor activation stimulates sensory nerve endings

2. info travels from the peripheral receptor to axons in the DPR or VPR

3. then travels through the spinal nerve and the dorsal root ganglion

4. reaches nucleus of the neuron in the DRG then travels in the dorsal root

5. ends in the dorsal horn of the spinal cord

- and - come together to form the spinal nerve

dorsal and ventral roots

what does the spinal nerve proper divide into?

the dorsal primary ramus and the ventral primary ramus

what does the DPR supply?

- deep back muscles (motor)

- skin of the back (medial and lateral)(sensory)

what does the VPR supply?

- all muscles except deep back muscles

- skin (lateral and anterior sides of the body)

what plexus do the VPRs form?

- cervical (C1-4)

- brachial (C5-T1)

- lumbar (L1-L4)

- sacral (L4-S4)

area of the spinal cord to which roots attach

segments

exit spinal cord to form the spinal nerve

roots

exits through intervertebral foramen; represents one spinal cord segment

spinal nerve proper

branches of spinal nerve

rami

spinal cord segment associated with a single spinal nerve

spinal cord level

represents sensory innervation

dermatomes

represents motor innervation

myotomes

area of skin supplied by a single spinal cord segment

dermatomes

dermatome of C2

back of head

dermatome of C5

tip of shoulder

dermatome of C6

thumb

dermatome of C7

middle finger

dermatome of C8

small finger

dermatome of T4

nipple

dermatome of T10

umbilicus

dermatome of L1

inguinal ligament

dermatome of L4

big toe

dermatome of S1

small toe

dermatome of S5

perianal area

ventral horn somatic motor axons from a single spinal nerve and the muscles supplied by that nerve

myotomes

a recognizable anatomical structure, used as a point of reference in establishing the location of another structure or in determining certain measurements

landmark

where is the biggest CV spinous process?

spinous process of the C7 vertebra

what spinal nerve only has motor innervations?

C1 DPR

what DPR innervated the skin on the back of the head?

C2 DPR

sheet or band of fibrous tissue that lies deep to the skin or invests muscles and various body organs

fascia

fatty layer of connective tissue deep to the skin

superficial fascia

dense, organized connective tissue sheet that binds together or invests the deep structures

deep fascia

separates the deep muscles of the back from the superficial muscles of the back; posterior to the sacrum it is fused to the tendon of the erector spinae muscles

thoracolumbar fascia

proximal attachment

origin

distal attachment

insertion

what is the origin and insertion of the trapezius?

origin: superior nuchal line, EOP, ligamentum nuchae, C7-T12 SPs

insertion: lateral 1/3 of clavicle, acromion process, spine of scapula

what are the actions of the trapezius?

- upper fibers: elevate scapula

- middle fibers: retract scapula

- lower fibers: depress scapula

what are the innervations and blood supply of the trapezius?

innervation: spinal accessory nerve (CN XI)

blood supply: superficial branch of transverse cervical vessels

what will happen if you have spinal accessory nerve damage?

- trapezius atrophy

- depressed shoulder girdle

- loss of scapular stabilization

- trapezius weakness

what is the origin and insertion of the latissimus dorsi?

origin: SPs T7 to sacrum, iliac crest, lower ribs, posterior lamella of thoracolumbar fascia

insertion: floor of intertubercular sulcus on humerus

what are the actions of the latissimus dorsi?

extend, adduct, and medially rotate humerus

what are the innervations and blood supply of the latissimus dorsi?

innervations: thoracodorsal nerve

blood supply: thoracodorsal artery

what is the origin and insertion of the levator scapulae?

origin: C1-C4 TPs

insertion: vertebral border of scapula above spine of scapula

what are the actions of the levator scapulae?

elevates scapula

what are the innervations and blood supply of the levator scapulae?

innervation: dorsal scapular nerve, C3 and C4 VPRs

blood supply: dorsal scapular artery or deep branch of transverse cervical artery

what is the origin and insertion of the rhomboid minor?

origin: C7-T1 SPs, ligamentum nuchae

insertion: vertebral border of the scapula at the root of the spine of the scapula

what is the origin and insertion of the rhomboid major?

origin: T2-T5 SPs

insertion: vertebral border of the scapula below the spine of the scapula

what are the innervations and blood supply of the rhomboids?

innervation: dorsal scapular nerve

blood supply: dorsal scapular artery or deep branch of transverse cervical artery

what are the actions of the rhomboids?

retraction of scapula and movement of shoulder girdle

what stabilizes the scapula when other muscles groups are active?

the rhomboids

what is the origin and insertion of the serratus posterior superior?

origin: ligamentum nuchae and C7-T3 SPs

insertion: ribs 2-5

what is the action of the serratus posterior superior?

elevates ribs (inspiration)

what is the innervation and blood supply of the serratus posterior superior?

innervation: VPR T2-T5

blood supply: intercostal artery

what is the origin and insertion of the serratus posterior inferior?

origin: T11-L3 SPs

insertion: ribs 9-12

what is the action of the serratus posterior inferior?

depresses the ribs (expiration)

what is the innervation and blood supply of the serratus posterior inferior?

innervation: VPR T9-T12

blood supply: intercostal artery