Mizzou DPT Gross Anatomy Lecture Exam 1

anatomical postion

1. standing upright

2. head forward

3. arms at sides, palms forward

4. legs close together, feet parallel, toes forward

anatomical planes

imaginary planes for sectional images and directions of movement

coronal/frontal plane

divides body into front and back (AP axis)

transverse/horizontal plane

divides the body into upper and lower parts

sagittal plane

divides body into left and right parts (ML axis)

midsagittal plane (median plane)

divides the body into equal right and left sides

parasagittal plane

divides body into unequal right and left sides

anterior/ventral

towards the front

posterior/dorsal

towards the back

superior/cranial

towards the head

inferior

towards the feet

caudal

towards the tail; only used for the human trunk

lateral

away from the midline (median plane)

medial

toward the midline (median plane)

proximal

closer to the root/attachment (limbs)

distal

further from the root/attachment (limbs)

superficial

closer to the surface

deep

further from the surface

body wall

a thick outer circle of tissue

body cavity

containing organs and related structures

organization of the body superficial to deep

skin -> superficial fascia -> deep fascia surrounding skeletal muscle -> bone -> body cavity

superficial fascia

subcutaneous tissue

superficial fascia composition

loose connective tissue, stored fat

superficial fascia contents

1. sweat glands

2. superficial blood vessels

3. lymphatic vessels

4. cutaneous nerves

deep fascia

deep to skin and superficial fascia; covers muscle

deep fascia composition

dense irregular connective tissue, no fat

extensions of deep fascia

investing fascia and fascial compartments

investing fascia (deep fascia)

surrounds muscles and neuromuscular bundle

fascial compartments (deep fascia)

thicker layer surrounding muscles separated by intermuscular septa

neurovascular bundle

nerve + artery + vein traveling together

nerves

spinal nerves and cranial nerves

blood vessels

arteries and veins

arteries

1. carry oxygen rich blood away from the heart --> body

2. relatively higher pressure than veins (pulse)

3. thicker wall

4. round lumen when cut

veins

1. return oxygen poor blood towards the heart

2. larger veins have valves

3. thinner wall, flatter structure than veins

4. more abundant, more variation

5. superficial and deep veins (run w/ arteries)

peripheral nervous system

conduct impulses to or from CNS

spinal nerves (PNS)

emerge at regular intervals from the spinal cord

ganglia (PNS)

collection of cell bodies outside CNS

cranial nerves (PNS)

emerge from the brain

central nervous system (CNS)

integrate, process, coordinate signals; brain and spinal cord

PNS neurons

afferent (sensory) and efferent (motor)

afferent (sensory) neurons

neurons that conduct impulses from the body to the CNS

efferent (motor) neurons

neurons that conduct impulses from the CNS to the body

spinal cord white matter

myelinated axons

spinal cord gray matter (H-shaped horns)

unmyelinated location of cell bodies

nerve

a collection of nerve cell fibers (axons of neurons), connective tissue, blood vessels

neuron dendrites

receive and carry impulses to cell body

neuron axon

carry impulses away from cell body

2 locations for cell bodies of neurons

ganglia (outside CNS) or nuclei (inside CNS)

multipolar neuron

1. one axon

2. many dendrites

3. cell body in CNS, axons in PNS

4. ex.) somatic and visceral motor neurons

pseudounipolar neuron

1. central process (impulse away from cell body)

2. peripheral process (impulse toward cell body)

3. cell body in PNS, most axons in PNS

4. ex.) sensory neurons in ganglia

number of nerves in PNS

33 total; 12 cranial nerves, 31 spinal nerves

somatic nervous system divisions

1. somatic motor (efferent) - skeletal muscles

2. somatic sensory (afferent) - touch, pain, pressure, temp., proprioception from receptors in skin to CNS

autonomic (visceral) nervous system divisions

1. visceral motor - sympathetic or parasympathetic system

2. visceral sensory

visceral tissues

1. glands

2. smooth muscle

3. cardiac muscle

4. organs

somatic sensory neurons

1. conduct impulses from the body to CNS

2. pseudounipolar from dorsal horn

somatic motor neurons

1. conduct impulses to skeletal muscle from CNS

2. somatic multipolar from ventral horn

visceral motor neurons

1. conduct impulses to organs from CNS (2 neuron system)

2. autonomic multipolar from ventral horn

somatic motor (efferent) pathways to body wall (multipolar)

1. ventral horn -> ventral root -> spinal nerve -> ventral ramus -> skeletal muscles (body wall) or limbs via peripheral nerves

OR

2. ventral horn -> ventral root -> spinal nerve -> dorsal ramus -> intrinsic back muscle

somatic sensory (afferent) pathway to body wall (pseudounipolar)

1. dorsal root ganglion -> skin, skeletal muscle, joint receptors (body wall) -> ventral ramus -> spinal nerve

OR

2. dorsal root ganglion -> skin, skeletal muscle, joint receptors (body wall) -> dorsal ramus -> spinal nerve -> dorsal root -> dorsal horn

somatic afferent (sensory) fibers only

dorsal root

somatic efferent (motor) fibers only

ventral root

somatic afferent and efferent fibers

1. spinal nerve

2. ventral ramus

3. dorsal ramus

dorsal rami

1. motor to epaxial muscles

2. sensation from overlying strip of skin

ventral rami

1. motor to hypaxial muscles

2. sensation from overlying skin

cutaneous nerves

branches that innervation the skin

extrinsic back/hypaxial muscle components

1. innervated by ventral ramus of spinal nerve

2. muscles that migrate ventral -> dorsal during development

3. actions: move and stabilize scapula, move arm, proprioception

4. attachments: generally 1 outside of the back

intrinsic back/epaxial muscle components

1. innervated by dorsal ramus of spinal nerve

2. developmentally dorsal muscles

3. actions: move and stabilize head, neck, and vertebral column

4. attachments: all within the back

spinal nerve ventral pathway

ventral horn -> ventral rootlets -> ventral root -> spinal nerve -> ventral ramus -> white or gray ramus communicans to sympathetic/paravertebral ganglion

spinal nerve dorsal pathway

dorsal horn -> dorsal rootlets -> dorsal root -> dorsal root ganglion -> spinal nerve -> dorsal ramus

vertebral column structure and spinal nerves

spinal nerves exit through intervertebral foramen

total number of vertebrae

33

number of cervical vertebrae

7 (C1-C7)

number of thoracic vertebrae

12 (T1-T12)

number of lumbar vertebrae

5 (L1-L5)

number of sacral vertebrae

5 fused (S1-S5)

number of coccygeal vertebrae

~4 fused (Co1-Co4)

location of cervical spinal nerves

1. C1 spinal nerve exits between skull and C1 vertebra (above C1)

2. C2-C7 nerves exit above the same named vertebra

3. C8 spinal nerve exits between C7-T1 (below C7)

location of spinal nerves (excluding cervical)

spinal nerves exit below their same named vertebra

number of cervical spinal nerves

8 (1 more cervical spinal nerve than cervical vertebrae)

number of thoracic spinal nerves

12

number of lumbar spinal nerves

5

number sacral spinal nerves

5

number of coccygeal spinal nerves

1

spinal nerves and plexuses

1. ventral rami interconnect, exchange axons, and form new nerves

2. many nerves carry axons from > 1 spinal cord level

3. primarily innervate limbs, also neck and pelvis

4. spinal cord segments where plexuses originate have spinal cord enlargements

thoracic spinal nerves

1. ventral rami of T1-T11 = intercostal nerves (run in the intercostal spaces)

2. ventral ramus of T12 - subcostal nerve (below the last rib)

cutaneous innervation of the back

mostly through dorsal rami

medial back of head cutaneous innervation

greater occipital nerve via dorsal ramus C2

central back and neck cutaneous innervation

dorsal rami C3-~S3

upper shoulder, lateral back of head and neck cutaneous innervation

ventral rami C2-C4

lateral back cutaneous innervation

ventral rami T2-T12 (intercostal and subcostal nerves)

greater occipital nerve

1. dorsal ramus of C2

2. exits between C1-C2 vertebrae

3. pierce semispinalis capitis, trapezius, or aponeurosis 2-3 cm lateral to external occipital protuberance

4. sensory: skin over neck and occipital bone

occipital artery

1. branch of external carotid artery

2. supplies posterior scalp

3. artery usually lateral to nerve

dermatome

one strip of skin innervated by one spinal nerve

myotome

collection of muscle fibers innervated by one spinal nerve

shoulder girdle

clavicle + scapula

os coxa bones

ilium, ischium, pubis

iliac crest vertebral level

L4

osteology of the back

1. shoulder girdle (clavicle + scapula)

2. vertebral column

3. rib cage

osteology of back functions

1. active movement of the trunk

2. support

3. respiratory function

4. protection

kyphosis (hunchback)

concave anteriorly; present in newborns