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USMLE Step 1 Systems > MSK, Skin, Connective > Flashcards

MSK, Skin, Connective Flashcards

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1
Q

Flattening of deltoid muscle with axillary n. injury = what injury?

A

Anterior Shoulder Dislocation

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2
Q

What nerve injury results in weak forearm flexion and absent biceps reflex? Where is loss of sensation associated with it?

A

Musculocutaneous N - innervates flexors and LATERAL forearm

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3
Q

Xeroderma Pigmentosum

A

Pigmented Dry Skin: erythema, scaling, hyperpig in light exposed areas, telangectasias, hypo/hyperpig areas AR - due to defect in DNA excision repair

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4
Q

What does the psoas major and iliacus function to do?

A

Sit up from a chair. Q7621

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5
Q

What does the obturator n. innervate?

A

ADductors of the thigh

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6
Q

Anatomy of Striated Muscle Sarcomere

A

Test ID: 36624218 “An Interesting Zoo Must Have Mammals” Actin in the I band attaches at the Z line, Myosin in the H band attached at the M-line”

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7
Q

What cytokines induce isotype switching?

A

IL 4 (from TH2 cells)

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8
Q

Anthrax results in what clinical picture?

A

Necrotic center with erythematous/edematous border.

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9
Q

Classic picture of N. gonorrhea

A

Young male/female, sexually active asymmetric polyarthritis of large joints Aspiration: intracellular org + high neutrophil

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10
Q

What factors are impt for osteoclast differentiation?

A

M-CSF and RANKL (produced by osteoblast)

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11
Q

What is the presentation of Rubeola?

A

Cough Coryza Conjunctivitis Koplick Spots (white, blue gray specks on buccal mucosa) Maculopapular Rash

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12
Q

What arteries are associated with the radial nerve and median nerve?

A

Radial - Deep Brachial Median - Brachial.

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13
Q

What part of long bone is hematogenous osteomyelitis most likely to occur?

A

Metaphysis - slow flowing sinusoidal vasculature, conductive to microbial passage. Adults less likely to develop this bc of epiphyseal closure

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14
Q

Wrinkles are due a decrease in what?

A

Collagen fibril production.

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15
Q

Embryologic origin of melanoma?

A

Melanocytes - derived from neural crest cells.

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16
Q

What is the difference btwn excitation contraction coupling in skeletal vs. cardiac vs. smooth muscle?

A

Skeletal - does not depend on extracellular Ca - depolarize L-type Ca channel -> conformational change -> opening of RyR1 Ca channel on SR -> release of Ca Cardiac - Ca induced Ca release - depolarize L-type Ca channel -> influx of extracellular Ca -> Ca activates RyR2 channels -> release of Ca from SR Smooth - - depolarize L-type Ca channel -> influx of extracellular Ca -> Ca dependent RyR Ca channel -> release of Ca from SR -> Ca binds CALMODULIN (no troponin in smooth muscle) -> activates myosin light chain kinase -> phosphorylation of myosin -> bind acting and cause contraction

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17
Q

What are markers of osteoblast activity vs. osteoclast?

A

Osteoblast = bone specific alkaline phosphatase Osteoclast = tartrate resistant acid phosphatase, urinary hydroxyproline, urinary deoxypyridinoline

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18
Q

Actinic Keratosis - risk of what?

A

SCC!

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19
Q

How are osteocytes connected to each other?

A

Gap Junctions! Send signals, exchange nutrients and waste products, can sense stress and modulate osteoblast activity

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20
Q

What substances stimulate acne formation?

A

Androgens, ex: anabolic steroids (methyltestosterone). Increase steps 1 and 2 below. Pathophys of Acne 1. Follicular epidermal proliferation 2. excessive sebum production 3. inflammation 4. Propionibacterium Acnes

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21
Q

What anti-inflam agent does not impair platelet aggregation?

A

Celecoxib (selective COX2 inhibitor) plts predominantly use COX1.

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22
Q

Vitiligo occurs as a result of ?

A

Autoimmune destruction of melanocytes. Decreased number of melanocytes (vs. albinism - decreased melanin)

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23
Q

Empty can tests what muscle

A

Supraspinatus

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24
Q

Cleft lip vs. Cleft palate

A

Lip = maxillary prominence and medial nasal prominence Palate = maxillary prominence fusion or its fusion to primary palate

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25
What is a Glomus Tumor?
Glomus Tumor: Sx: bluish neoplasm underneath the nail bed. Nl function: Thermoregulation. Glomus body is a neurovascular organ wrapped in smooth muscle -\> shunts blood away from skin in cold temps; shunts blood toward skin to dissipate heat when hot temp.
26
Attachments of ACL vs. PCL
Note: coronal MRI is always looking from the FRONT, idiot. ACL = lateral epicondyle -\> ant. intercondylar area of tibia PCL = medial epicondyle -\> post intercondylar area of tibia
27
What condition associated with pathological fracture? What are the lab values PTH, Ca, PO4 associated with it?
Osteoporosis - Decrease in trabecular bone mass - NORMAL lab values.
28
Bullous pemphigoid - antibodies against ?
Hemidesmosome "antibdodies are "bullow" the epidermis"
29
What do integrins bind to?
Collagen, Laminin, Fibronectin.
30
How is the pulmonary system involved in ankylosing spondylitis?
Costovertebral Enthesopathy -\> Dec. Chest Expansion and Hypoventilation.
31
Anterior and Posterior Dislocation of the Knee would injure what structure?
Popliteal Artery.
32
What nerve and artery go with each of the following: Axilla/Lateral thorax Surgical neck of the humerus Midshaft of the humerus Distal humerus/Cubital Fossa Popliteal Fossa Posterior to the Medial Malleolus
Axilla/Lateral Thorax = Long thoracic n., Lateral thoracic a. Surgical neck of the Humerus = Axillary, Posterior Circumflex Midshaft of the Humerus = Radial, Deep Brachial Distal Humerus/Cubital Fossa = Median, Brachial Popliteal Fossa = Tibial n., Popliteal Artery Posterior to the Medial Malleolus = Tibial n., Posterior Tibial
33
Achondroplasia - gene and inheritance
FGF3 constitutive activation -\> inhibits chondrocyte proliferation -\> inhibits endochondral ossification -\> failure of longitudinal growth -\> short extremities, large head. Inheritance: Sporadic -\> AD
34
What bone disease associated with eating mostly processed foods + little sun exposure?
Vit D deficiency = Rickets or Osteomalacia.
35
What bone disease associated with each of the following: * osteoid matrix, unmineralized * pancytopenia, nerve impingement * mosiac of woven and lamellar bone * hearing loss * spongy bone loss * endochondral ossification failure
* osteoid matrix, unmineralized = Osteomalacia, Rickets (Vit D deficiency) * pancytopenia, nerve impingement = Osteopetrosis - thickened bone from defective osteoclasts * mosiac of woven and lamellar bone = Paget's * hearing loss = Paget's * spongy bone loss = Osteoporosis * endochondral ossification failure = Achondroplasia
36
Callus caused by thickening of which skin layer?
Most superficial - Stratum corneum.
37
What injuries predispose to ulnar n. injury?
1. Fracture of the Medial Epicondyle 2. Fractured hook of hamate.
38
How does Avascular Necrosis present? What are some conditions are predispose to it?
Pain upon weight-bearing, passive, active movement. No erythema, swelling, or temperature changes. MRI is diagnostic modality. Predisposed: - Sickle Cell - SLE (vasculitis) - High dose corticosteroids - Alcoholism
39
What type of muscle fiber has high myoglobin and mitochondrial content? And what muscles have these fibers?
Type I fibers = aerobic metabolism (have myoglobin for O2 and mitochondra for oxidative phos) - predominantly muscles that maintain posture, such as PARASPINAL and soleus. (Type II fibers = anaerobic, rapid forceful pulses of movement)
40
41
What muscles does the median n. traverse?
Flexor digitorum profundus and Flexor digitorum superficialis before entering wrist and hand under flextor retinaculum.
42
What are the following Buzzwords associated with? - osteoid matrix - trabecular thinning with fewer interconnection - subperiosteal bone resorption with cystic degeneration - lamellar bone resembling mosaic - spongiosa filling medullay canal with no mature trabeculae
- osteoid matrix: unmineralized bone - Vit D Deficiency - trabecular thinning, few interconnection: Osteoporosis - subperiosteal bone resorption: HyperPTH - mosaic: Paget's - spongiosa filling medullary canal: Osteopetrosis (normally BM replaces spongiosa, but here you have persistence of primary, unmineralized bone)
43
Sweat glands - what type of gland?
APOCRINE. secrete into hair follicles rather than directly onto skin.
44
Contact Derm Histology
Spongiosis = epidermal accumulation of edematous fluid in intracellular spaces
45
Buzzwords: - Acanthosis - Dyskeratosis - Hyperparakeratosis - Spongiosis - Hypergranulosis
- Acanthosis = Psoriasis (inc. in stratum spinosum) - Dyskeratosis = Squamous cell carcinoma (abnl keratinization of individual cells) - Hyperparakeratosis = Actinic Keratosis (retained nuclei in stratum corneum) - Spongiosis = Contact Derm - Hypergranulosis = Lichen Planus (excessive granulation of stratum granulosum)
46
Fibromyalgia
Pt: Female, 20-50s - Diffuse MSK pain with stiffness, paresthesia, poor sleep, fatigue, emotional disturbance. - Gets worse with exercise. - Tenderness in specific points - "trigger points" Tx: regular exercise, Pregabalin, SNRI
47
Polymyalgia Rheumatic
Pt: Women \> 50. Old! - proximal JOINT pain and stiffness - shoulder, hips, pelvic girdle. - NO muscle weakness - fever, malaise, weight loss. - Assoc. with temporal arteritis Labs: Inc. ESR, CRP Tx: low dose corticosteroids
48
PABA in sunscreen blocks what type of UV rays?
UVB ONLY!
49
Psoas Abscess - presentation? Where on CT?
Hematogenous, Lymphatic, or Local Spread of infection. Fever, Back/Flank pain, Inguinal mass, Difficulty walking PSOAS SIGN: pain when hip is extended OR pain upon hip flexion against resistance CT: located immediately lateral to the vertebral bodies
50
Muscle regulatory fibers
1. Muscle spindle/Group 1a, II sensory axons = Intrafusal fibers (parallel to the extrafusal fibers). - sense changes in muscle length - stretch reflex: if muscle stretched, reflexive activation of alpha neuron - contraction to resist the stretch (DTR) 2. Golgi Tendon Organ - sense changes in mucle tension/force - once it reaches a threshold, sends inhibitory signal to alpha neuron - sudden muscle relaxation - protects muscle.
51
Differences in Bone density curves most due to what?
Genetic factors Smaller role: Ca intake, physical activity.
52
Hypercalcemia in Sarcoidosis?
Increased extrarenal formation of 1,25 dihydroxy vit D by activated macrophages (T cells release IFNg which increases activity of 1 alpha hydroxylase in macrophages).
53
Epithelial Junctions
Tight = claudins Adherens = actin + cadherins Desmosome = keratin + desmoplakin Gap = connexons Hemidesmosome = keartin to basement membrane Integrins = collagen, laminin, fibronectin.
54
Neurovascular Pairings for the following locations: Axillary/lateral thorax cubital fossa/distal humerus posterior to medial malleolus
axillary = long thoracic n., lateral thoracic a. cubital fossa/distal hum = median n., brachial artery post medial malleolus = tibial, posterior tibial
55
Osteoporosis = tx, and what to avoid
Tx: - bisphosphonates - inhibit osteoclasts - denosumab - monoclonal Ab against RANKL - raloxifene - SERM bone agonist - PTH pulsatile - stimulates osteoblasts, no more than 2 yrs Avoid - smoking, EtOH, chronic steroid use - PPI - inhibits absorption of Ca
56
Dermatologic Lesions associated with: Hyperkeratosis Parakeratosis Spongiosis Acantholysis Acanthosis
Hyperkeratosis - inc. s. corneum = psoriasis, calluses Parakeratosis - retained nuclei in s. corneum = psoriasis Spongiosis - edema in epidermis = eczema Acantholysis = separation of cells = pemphigus vulgaris Acanthosis = inc s. spinosum = acanthosis nigricans
57
Lumbar Lordosis caused by excessive contraction of \_\_\_\_\_\_.
Hip flexors.
58
What muscle pulls the clavicle inferolaterally?
Deltoid.
59
What muscle pulls the clavicle superomedially?
Trapezius
60
Reactive Arthritis Sx
Can't pee, see, climb a tree Urethritis Conjunctivitis, Anterior Uveitis Arthritis + Sacroillitis 20% cases HLAB27 associated. Post GI (shigella, salmonella, yersinia, campylobacter) Post GU (urethritis) Post Chlamydia
61
Dysplastic Nevus
Numerous dysplastic nevi in young person with FHx of melanoma in more than 3 1st degree relatives. Mutations in CDKN2a - 9p21.
62
Knee arthritis, conjunctivitis, vesicular rash on palms. Arthritis treated with ibuprofen. Conjunctivitis treated with topical antibiotics. What was initiating event?
Reiter's Reactive Arthritis. Commonly following GI or UTIs.

USMLE Step 1 Systems (11 decks)

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