Week 1 Hitchhiker's Guide

Question 1

Is moving your arm forward flexion or extension?

Answer 1

Flexion (think “forward flexion”)

Question 2

Is moving the thumb on top of palm abduction or adduction?

Answer 2

Abduction

Question 3

Is moving the thumb away from the body flexion or extension?

Answer 3

Extension

Question 4

What structures does acne affect?

Answer 4

Dermis and epidermis.
-Sebaceous follicle in dermis produces too much sebum; shed keratin and sebum accumulate

Question 5

Where would you instill local anesthesia for a office procedure such as a skin biopsy or suturing a laceration?

Answer 5

Hypodermis/ SQ/ superficial fascia

Question 6

What is the clinical significance of the skin tension lines?

Answer 6

You should cut parallel to them for better healing; keloids are a risk if perpendicular

Question 7

What components of the skin are involved in stretch marks?

Answer 7

Collagen & elastic fibers in the dermis

Question 8

Differentiate between superficial, partial thickness, and full thickness burns and clinical presentation

Answer 8

1) Superficial: just superficial part of epidermis (ex: mild sunburn)
2) Partial thickness: all of epidermis and the superficial layer of dermis. Basal layer can help with regeneration. Sweat glands and hair are not damaged except their most superficial parts.
3) Full thickness: entire epidermis, all of dermis, and deep fascia. Sometimes underlying muscle as well. Will require a skin graft, no regeneration.

Question 9

Describe how long bones grow

Answer 9

Long bones grow via endochondral ossification: 1) The mesenchymal cells condense and differentiate into chondroblasts, forming the cartilaginous bone model.
2) In the midregion, cartilage then calcifies & periosteal capillaries grow into calcified cartilage to form a periosteal bud.
3) They initiate the primary ossification center, which creates the diaphysis.
4) Secondary ossification center creates epiphysis.
5) Epiphyseal plate formation

Question 10

Describe the anatomical parts of adult and immature bones

Answer 10

1) Adults: Diaphysis, epiphysis, metaphysis, epiphysial line.
2) Immature: Same as adult, but epiphysial plate instead of line.

Question 11

Describe the vascular supply of bone

Answer 11

1) Nutrient arteries that arise outside the periosteum go through the nutrient foramina and split in the medullary cavity into longitudinal branches.
-These branches supply the bone marrow, spongy bone, and deeper parts of compact bone.
2) Smaller branches of periosteal arteries supply the compact bone (so if periosteum was removed, bone would die).
3) Metaphysial and epiphysial arteries supply the ends of the bones.

Question 12

Describe the nerve supply of bone

Answer 12

Bone doesn’t contain many sensory nerves, but the periosteum contains many

Question 13

1) What initiates primary ossification centers? When do they begin ossifying?
2) When do secondary ossification centers form, and what do they make?

Answer 13

1) Primary ossification center is initiated by periosteal capillaries, begin ossification before birth
2) Secondary ossification centers appear after birth and ossify the epiphyses.

Question 14

What can having too many ossification centers cause?

Answer 14

Extra ossification centers form extra bones

Question 15

What is the assessment of bone age an application of?

Answer 15

A clinical application of x-rays

Question 16

Are epiphyses easily broken? Describe

Answer 16

No; an injury that causes a fracture in an adult will usually cause displacement of an epiphysis in a child; these two things can be mistaken without knowledge.

Question 17

1) Define avascular necrosis
2) Give an example

Answer 17

1) Bone death due to lack of blood supply (ex: femoral head)
2) After every fracture, small areas of adjacent bone undergo necrosis

Question 18

1) What is degenerative joint disease (DJD) also known as?
2) What is it?

Answer 18

1) Osteoarthritis
2) Synovial joints’ articular cartilage gets worn down

Question 19

List and describe the 3 types of joints

Answer 19

1) Fibrous joints: gomphoses (like teeth), syndesmoses, and sutures (like skull sutures)
2) Cartilaginous joints: synchondroses permit growth of length of bone, allow slight bending) and symphyses (like intervertebral disc, slightly movable, strong)
3) Synovial joints: most common, movable, synovial fluid and articular surface.

Question 20

List and describe the 3 types of muscle

Answer 20

1. Skeletal: striated, somatic innervation
2. Cardiac: striated, visceral/ autonomic innervation
3. Smooth: not striated, visceral/ autonomic innervation

Question 21

List the two types of contraction, and the movements that happen during contraction

Answer 21

1. Isometric: muscle doesn’t move but still exerts force
2. Isotonic: muscle moves; two parts:
   a. Concentric: muscle shortens
   b. Eccentric: muscle lengthens

Question 22

1) What is the functional unit of a muscle?
2) What are its components?

Answer 22

1) A motor unit
2) Consists of a lower motor neuron and the muscle fibers it innervates

Question 23

1) What is muscle atrophy? What can cause it?
2) What is muscle hypertrophy? What can cause it?

Answer 23

1) Atrophy: muscle loss, can be due to stroke, paralysis, lesion of a nerve, a primary muscle disorder, immobilization of a limb (cast or sling), or just not moving
2) Hypertrophy: muscle growth, can be due to weightlifting/ exercise (or compensatory hypertrophy can increase cardiac muscle cells)

Question 24

How is blood moved within the arterial system?

Answer 24

Musculovenous pump helps return blood to heart, heart pumps blood throughout the body

Question 25

List the order of blood flow starting with artery

Answer 25

Artery, to arteriole, to capillary, to venule, to vein, to superior and inferior vena cava, to heart.

Question 26

What is the musculovenous pump?

Answer 26

As muscles contract in the legs, deep accompanying veins are compressed within the vascular sheath, resulting in increased return of venous blood.

Question 27

What are anastomoses and why are they important?

Answer 27

-Alternate routes for blood in case the primary route is blocked (because of compression, position of a joint, pathology, surgical ligation, etc).
-These collateral routes ensure that the part distal to the blockage doesn’t experience ischemia.
-Takes time for them to develop.

Question 28

What are true terminal arteries and what happens if they’re blocked? Give an example

Answer 28

Arteries that don’t anastomose with nearby arteries, and if they’re blocked, then the body part distal to that will die.
-ex: occlusion of terminal arteries of retina will result in blindness

Question 29

What are functional terminal arteries?

Answer 29

-Arteries that do anastomose, but have ineffective anastomoses
-Examples include arteries supplying parts of the brain, kidney, spleen, liver, and intestines.

Question 30

Define arteriosclerosis and name a type of it

Answer 30

Most common group of acquired arterial disease, it’s the hardening of arteries due to loss of elasticity and thickening of their walls. ex: atherosclerosis

Question 31

1) Define atherosclerosis
2) Describe what it does

Answer 31

1) A type of arteriosclerosis characterized by the buildup of fat (mostly cholesterol) in arterial walls
2) Cholesterol builds up, then atheromatous plaque (a buildup of calcium deposits that form after the onset of cholesterol buildup, causing narrowing and irregularity) forms. -This may result in the formation of a thrombus (thrombosis; a buildup of RBCs and other things; aka blood clot)

Question 32

What can a thrombus do and what condition is this seen in?

Answer 32

-Can occlude an artery or be flushed into the bloodstream (embolus), causing ischemia and infarction. Infarction is local death of an organ or tissue. Ex: myocardial infarction, stroke, or gangrene (necrosis of limb parts)
-Seen in atherosclerosis

Question 33

1) When do varicose veins form?
2) What part of the vein is no longer working?

Answer 33

1) When veins lose their elasticity or if deep fascia becomes incompetent at sustaining the musculovenous pump; veins dilate and can become swollen and twisted under the pressure of supporting a column of blood against gravity.
2) Their valve cusps no longer meet or have been destroyed by inflammation (incompetent valves)

Question 34

List some surface lymph nodes

Answer 34

Superficial cervical nodes, inguinal, popliteal

Question 35

List the parts of a neuron and define each

Answer 35

1) Cell body (soma): Contains the nucleus and organelles.
2) Dendrites: Branch-like structures that receive signals from other neurons.
3) Axon: A long fiber that transmits electrical impulses away from the cell body to other neurons or effectors.
4) Synapse: The junction between two neurons where neurotransmitters are released to transmit signals.

Question 36

What do neuroglia do?

Answer 36

Support, nourish, and protect neurons

Question 37

What are the structural divisions of the nervous system? Define both

Answer 37

1) CNS: brain and spinal cord, nuclei, tracts
2) PNS: all nerves (cranial and spinal) and ganglia.

Question 38

1) What does the somatic nervous system supply? (both motor and sensory divisions)
2) What does the visceral nervous system supply? (both motor and sensory divisions)

Answer 38

1) Somatic (conscious): Its motor division supplies skeletal muscle; its sensory division carries touch and pain from muscles, skin, and joints.
2) Visceral (autonomic): Its motor division supplies smooth muscle, glands, and the conducting system of the heart; its sensory division carries pain and reflex info from the viscera of body cavities

Question 39

What are the functional divisions of the nervous system? Briefly describe each

Answer 39

i. Sensory: Sensation
ii. Motor: movement

Question 40

In a pain withdrawal reflex:
1) Where are the pain receptors located? What transmits the pain signal?
2) Where are the sensory nerve bodies located? Where does the axon go, and what does it transmit to?
3) What communicates with the LMNs, and where are they? What travels to the target muscle?
4) What tells you to pull your hand away from something hot?

Answer 40

1) i. Nociceptor (pain receptor, a type of sensory receptor) close to effector organ detects harmful stimulus. Sensory neuron transmits pain signal to sensory nerve body.
2) Sensory nerve body in the dorsal root ganglion receives pain signal from sensory neuron. Sensory neuron’s axon enters the spinal cord via the dorsal root and transmits the signal to an interneuron in gray matter of spinal cord (or directly to the motor neuron in simpler reflexes).
3) Interneuron transmits the signal to the low motor neuron in the ventral horn of spinal cord. Its axon leaves via the ventral root and travels to target muscle.
4) LMN stimulates the muscle to contract, pulling your hand away.

Question 41

How do the sympathetic nerves exit the CNS and distribute to the body?

Answer 41

-Sympathetic nerve presynaptic cell bodies are in intermediolateral spinal columns (IMLs; in lateral horn) which span from T1-L3.
-Leave (IMLs) via anterior roots to anterior rami
-Pass through white rami communicantes to sympathetic trunk, where they then follow one of 4 paths

Question 42

How do the sympathetic nerves reach structures within the head?

Answer 42

1) Starts at sympathetic chain.
2) Post synaptic cell bodies in superior cervical ganglion,
3) Ascend into cranium via periarterial plexus of nerves following branch of the carotid artery and
3) Hitch a ride with cranial nerves to target organ (eye via CN III, oculomotor nerve).

Question 43

How do the sympathetic nerves reach structures at the neck and below?

Answer 43

1) Postsynaptic fibers arise from T1-T4
2) Pass from paravertebral ganglia of sympathetic trunk via Gray rami communicantes
3) To adjacent anterior rami of spinal nerves
4) And enter all 31 spinal nerves (Including posterior rami of spinal nerves)

Question 44

How do the parasympathetic nerves reach structures within the head?

Answer 44

Solely cranial outflow; via: 1) 3 CNs (III, VII, IX)
2) 4 pair of ganglia:
-Ciliary (pupil),
-Pterygopalatine (lacrimal gland)
-Otic (parotid gland)
-Submandibular (Sublingual and submandibular salivary glands)

Question 45

How do the parasympathetic nerves reach structures at the neck and below?

Answer 45

Both cranial and sacral outflow:
1) Cranial: Parasympathetic goes to thoracic and abdominal viscera via CN X, Vagus n.
2) Sacral: Leaves the S 2-3-4 cord segment’s lateral horn grey matter via anterior S2-4 spinal nerve, anterior rami to pelvic splanchnic nerves

Question 46

What are the 2 sources of parasympathetic nerves to the GI and pelvic organs

Answer 46

Cranial outflow and sacral outflow

Question 47

1) What is innervated by parasympathetic cranial outflow?
2) What about sacral outflow?

Answer 47

1) The head above the neck, all thoracic viscera and all GI to the splenic flexure of colon
2) Innervates the pelvic viscera, erectile tissues of external genitalia, bladder, and GI from Pelvic flexure of colon distal (descending colon, sigmoid colon, & rectum)

Question 48

What is the location and function of the paravertebral ganglia?

Answer 48

Sympathetic trunks or chains on either side of vertebral column; contain sympathetic postsynaptic neurons.

Question 49

What is the location and function of the sympathetic truck?

Answer 49

Anterolateral to vertebral column on either side. Carries preganglionic sympathetic fibers that synapse in the ganglia.

Question 50

What is the location and function of the prevertebral ganglia?

Answer 50

In plexuses that surround origins of the main branches of the abdominal aorta (celiac ganglia) and the aortic, hypogastric, and pelvic plexuses that descend from them; sympathetic postsynaptic neurons located here.

Question 51

Where are the parasympathetic ganglia located and what are their function?

Answer 51

Close to the organs they innervate; when stimulated, they allow the body to perform “rest and digest” functions (slows heart rate, lowers BP, increases salivation, etc)

Question 52

Distinguish between preganglionic and postganglionic fibers of the autonomic nervous system.

Answer 52

1)”Preganglionic” refer to nerve fibers that originate in the central nervous system (brain or spinal cord) and travel to a ganglion (a cluster of nerve cell bodies outside the CNS), where they synapse with
2) “Postganglionic fibers” extend from the ganglion to the target organ, directly controlling its function
-Essentially, preganglionic fibers are the “first leg” of the signal from the CNS to the organ, while postganglionic fibers are the “final leg” that delivers the signal to the target tissue

Question 53

Describe the 3 steps of the pupillary light reflex

Answer 53

1) Light enters the eye, stimulating photoreceptors in the retina which send signals via the optic nerve to the brain
2) Signals travel from the brain to the oculomotor nerve’s nucleus, then via the oculomotor nerve to the ciliary ganglion where they synapse.
3) Postganglionic fibers from the ciliary ganglion innervate the iris sphincter muscle, causing it to contract and constrict the pupil

Question 54

Describe the enteric nervous system; how does it function and what is it made of?

Answer 54

1) Functions autonomously from CNS; it’s only modulated by para and sympathetic input
2) Made of 2 interconnected plexuses
A) Myenteric plexus: wall smooth muscle
B) Submucosal plexus: deep to mucosa

Question 55

What are the 3 ways the sympathetic nerves can reach the body? Describe each

Answer 55

1) Synapse at level of exit: postsynaptic distributed by thoracic cardiopulmonary splanchnic nerve (to middle trunk)
2) Descend and then synapse: postsynaptic distributed by spinal nerves (to lower trunk and limb)
3) Don’t synapse: and enter abdominopelvic splanchnic nerve (to abdominopelvic viscera)

Question 56

1) Describe visceral afferent sensation
2) Describe its path

Answer 56

1) Normal visceral activity usually produces no stimulation of conscious perception; pathologic, such as ischemia, lowers normal threshold and pain is perceived.
2)
-Most visceral reflex nerves follow the parasympathetic fibers retrograde
-Most visceral pain impulses follow the sympathetic fibers retrograde and synapse in DR.

Question 57

List the 4 curves of the spine, whether they’re primary or secondary, and what it’s called when their angles change too much

Answer 57

1) Cervical lordosis: in neck, secondary curve
2) Thoracic kyphosis: curve of the thoracic spine, primary curve
-Excessive curvature here is called excessive thoracic kyphosis, aka kyphosis. Characterized by an abnormal increase in thoracic curvature; the vertebral column curves posteriorly
3) Lumbar lordosis: Curve of lumbar spine, secondary curve
-Excessive lumbar lordosis: Excessive anterior rotation of the pelvis, producing excessive lumbar curvature
4) Sacral kyphosis: Curve of sacrum, primary curve

Question 58

1) What is the external occipital protuberance?
2) What is the nuchal groove?

Answer 58

1) External occipital protuberance: bump on occipital bone
2) Nuchal groove: groove on back of neck

Question 59

1) Describe the shape of the thoracic spinous processes.
2) Describe the shape of the lumbar spinous processes.
3) Where is the supraspinous ligament?

Answer 59

1) Thoracic: long and overlap with sub adjacent vertebral body
2) Lumbar: spinous processes are short and sturdy here
3) Runs vertically down the spinous processes

Question 60

1) Where are the iliac crests?
2) Where is the iliac tubercle?

Answer 60

1) Iliac crests: top part of ilium bone
2) Iliac tubercle: towards the anterior side of the ilium near the iliac crest

Question 61

Where is the median crest of sacrum?

Answer 61

The medial crest (bumps) on the sacrum

Question 62

Compare the numbers of vertebrae to the numbers of spinal nerves

Answer 62

Vertebrae: C7, T12, L5, S5, C4
Spinal nerves: C8, T12, L5, S5, C1

Question 63

Where do the spinal nerves exit with respect to the vertebral number?

Answer 63

Cervical nerves exit through the IV foramen superior to corresponding vertebral number, thoracic exit below.

Question 64

Locate and describe what structures pass through the:
1) Vertebral foramen
2) Interverbal foramen
3) The foramen transversarium

Answer 64

1) Vertebral foramen: big hole in middle; spinal cord
2) Foramen transversarium: tiny lateral holes; vertebral artery & vein and sympathetic nerves
3) Intervertebral foramen: formed by the notches of pedicles; spinal nerves exit through here, ganglion

Question 65

1) What is the vertebral body?
2) What two things make up the vertebral arch? Describe them
3) Where is the spinous process?
4) Where is the transverse process?

Answer 65

1) Main round part
2)
A) Pedicle: connects lamina and transverse process to body of vertebrae
B) Lamina: forms a triangle
3) Spinous process: on top of lamina
4) Transverse process: lateral to lamina

Question 66

1) What are the vertebral articular processes and facets?
2) What is the vertebral foramen?

Answer 66

1) Inferior and superior “bumps” on the vertebrae
2) The big hole in the middle of the vertebrae that the spinal cord goes through

Question 67

Identify the vertebral structures involved in spondylosis/spondylolisthesis

Answer 67

Defect in pars interarticularis of neural arch (lamina between the two articular processes)

Question 68

Which vertebrae are associated with ribs and where do the ribs articulate with each of its vertebra?

Answer 68

The thoracic vertebrae (T1-10); transverse costal facet

Question 69

Anatomically, why is the lumbar vertebra the best region to access the subarachnoid space and obtain cerebral spinal fluid?

Answer 69

The spinal cord ends around L1-L2 in adults, and the lumbar cistern allows easy CSF access, and it has the biggest space between spinous processes

Question 70

1) What lumbar spinal stenosis?
2) What can complicate it?
3) What’s its treatment?

Answer 70

1) The narrowing of the lumbar spinal canal compressing the spinal nerves
2) The presence of a protruding IV disc; ligamentous degeneration and arthritic proliferation can also complicate by further narrowing the canal. Usually age related.
3) Laminectomy

Question 71

What is vertebral osteoporosis? How is this seen?

Answer 71

The demineralization of the vertebrae, seen as lower radiodensity.

Question 72

What structures are compromised with spinal stenosis?

Answer 72

One or more lumbar vertebrae’s vertebral foramen is narrowed

Question 73

What structure(s) are involved in spina bifida (when pregnant, we want you to take PNV with folate to reduce the risk of this congenital condition)?

Answer 73

The vertebral arch of L5 and/or S1 doesn’t fully close due to neural tube defects

Question 74

Define laminectomy and when it may be done

Answer 74

The removal of the lamina and spinous process (or sometimes refers to transecting the pedicle) to relieve spinal pressure on the cord or nerve roots due to a tumor, herniated IV disc, or bone hypertrophy

Question 75

Describe dislocated vertebrae

Answer 75

-Usually in cervical vertebrae, takes less force than a fracture, sometimes doesn’t damage spinal cord.
-If the dislocation doesn’t involve “facet jumping”, it may slip back into place on its own.
-Resulting soft tissue damage can be seen on MRI.

Question 76

What is whiplash?

Answer 76

Hyperextension of the neck (usually from a rear-ending car accident), involves the stretching or tearing of the anterior longitudinal ligament

Question 77

What is the most common non-cervical vertebrae to be fractured? Why?

Answer 77

T11-12 because of the abrupt transition between immobile thoracic and more mobile lumbar regions

Question 78

Compare the spinal cord, conus medullaris, and cauda equina and relate these structures to the level of spinal cord in children and adults.

Answer 78

1) Spinal cord: goes from brainstem to L1-2 disc in adults, L2-3 disc in newborns
2) Conus medullaris: the terminal end of the spinal cord
3) Cauda equina: the nerves continue as the cauda equina through sacrum and coccyx, looks like a horse’s tail)

Question 79

Describe the general concept in the distribution of spinal cord vasculature

Answer 79

1) Segmental medullary arteries are very important for spinal cord vasculature, specifically the great anterior segmental medullary artery.
2) Sometimes the anterior spinal artery is purposefully clamped during surgery
-In which case, pts may lose sensation and voluntary movement at and below the site of ischemia. This is secondary to neuron cell death.

Question 80

Define ischemia (in the context of the back), when it may occur, and what it can lead to.

Answer 80

1) Loss of blood supply to the spinal column; can be caused by fractures or dislocations. This can lead to muscle weakness or paralysis.
-Sometimes purposefully done during surgery, in which case patients may lose sensation and voluntary movement at and below the site of ischemia. This is secondary to neuron cell death.

Question 81

1) What is the importance of the vertebral venous plexuses?
2) Why are they also a negative thing?

Answer 81

1) Blood may return from pelvis and abdomen through this plexus when the inferior vena cava is obstructed; goes through the superior vena cava this way.
2) Can also provide a route for cancer metastasis to the vertebrae and brain from an abdominal or pelvic tumor

Question 82

1) What spaces do a lumbar puncture pass through?
2) Where specifically is CSF collected from?

Answer 82

1) Passes through the epidural space, dura, and arachnoid mater into the subarachnoid space.
2) Specifically, CSF is gathered from the lumbar cistern (usually below L1)

Question 83

1) What space do epidurals enter?
2) What does it effect?

Answer 83

1) The epidural space is entered to administer anesthesia during labor.
2) Works on spinal nerve roots of cauda equina after they exit dural sac.

Side note: Can also be done from the sacral canal through sacral hiatus (called caudal epidural) or through the posterior sacral foramina (trans-sacral epidural)