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MSK Flashcards

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USMLE® Step 1 flashcards
1
Q

Osteoclast Formation

A

*Marrow pre-cursor produces multinucleated osteoclast

*M-CSF induces myeloid precursors to differentiate into osteoclast precursors that express RANK
- RANK –> NK-kB –> RANK-L triggers osteoclast precursors

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2
Q

Hyaline Cartilage Model
- What type of division?
- What type of Growth?

A

*Chondrocyte Division
*Growth: Appositional (diameter) growth via addition of matrix to peripheral surface cartilage

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3
Q

Periosteum Formation
- What do chondroblasts develop>

A

New chondroblasts develop on the perichondrium

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4
Q

Bony Collar Formation
- Where do osteoblasts secrete?
- Provide support for what?

A

*Osteoblasts secrete osteoid against shaft of cartilage model

*Collar acts as support for the developing bone

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5
Q

Matrix Calcification

A

Growth of chondrocytes w/in the primary ossification
- Begin secreting alkaline phophatase which is needed for mineral deposition
- Death of the chondrocytes leads to cavitation in middle of bone

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6
Q

Chondrocytes secrete

A

*Alkaline Phophatase
*VEGF

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7
Q

Secondary Ossification
*Where does it appear?
*When does the epiphyseal plate form?

A

*Appears at epiphysis of long bones
*Mesenchyme + blood vessels carried in via periosteal buds
*Epiphyseal plate forms once primary + secondary ossification centers meet

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8
Q

Osteoporosis
*Main Cause?
*Other causes?
*Presentation
*Diagnosis
*Tx:

A

*Due to age-related drops in estrogen

  • Estrogen decreases = bone resorption increases & bone density decreases
  • Estrogen usually blocks bone resorption via blocking IL-6

*ETOH, Hyperparathyroidism, Multiple Myeloma, Hyperthyroidism (thyroid induces osteoclasts)

*Presentation:
- Non-trauma related fractures
- Vertebral Compression fracture

*Dx: DEXA Scan, Fragility fracture

*Tx:
- Lifestyle modifications (smoking cessation, alcohol cessation, calcium/vitamin D, exercises)
- Bisphosphonates: ends in “-dronates”: promote osteoclast apoptosis
- Can’t tolerate bisphosphonates: try Teriparatide OR SERM’s (Raloxifene)

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9
Q

Osteomalacia / Rickets
*What happens in children?
*Inheritance
*Mutation
*Presentation
*Manage

A

*Rickets happens in children
*Inheritance: X-linked dominant
*Mutation of PHEX gene, PHEX usually provides instructions needed for proper bone/teeth development
- Regulates phosphate in body

*Presentation:
- Bowing of legs
- Craniotabes
- Wrist/Ankle Thickening

*Manage: Vitamin D + Ca2+

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10
Q

Scurvy
*Cause?
*Presentation:

A

*Cause: Vitamin C Deficiency
- Vitamin C needed for collagen hydroxylation

*Presentation: Bleeding gums, bleeding from hair follicles, easy bruising

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11
Q

Osteitis Deformans (Paget’s Disease)

*Cause
*Presentation
*Dx & Tx

A

*Cause: Increased osteoclastic activity w/ abnormal deposition of lamellar bone interspersed w/ woven bone
- Osteoclasts = sensitive to vitamin D

*Presentation:
- Intranuclear inclusions
- Bone pain that worsens w/ activity
- Bony Deformity (sclerotic lesions)
- Broken Bones
- Elevated alkaline phosphatase levels
- Normal serum Ca2+ & phosphorus levels

*Dx & Tx:
- Dx: Sclerotic Lesions
- Tx: (Nitrogen containing) Bisphosphanates – Zoledronate, Pamidronate, Risedronate, Alendronate

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12
Q

Pyogenic Osteomyelitis
*What?
*Organism?
- Organism associated w/ sickle cell patients? IV drug users?
*Who?
*Where?

*Presentation:

*Dx
*Tx

A

*Bone infection
*Caused by Staph Aureus, aerobic gram-neg. bacilli &/or coagulase negative staph species
*Sickle cell patients: salmonella
*IV drug users: pseudomonas
*Who?: Affects kids
*Where: Long bones

*Gradually worsening
*Bone Pain
*Swelling, warmth, tenderness

*Dx: Inflammation + Osteonecrosis + Periosteal elevation thickening + MRI

*Tx: Staph: Naficillin, Oxacillin,
(Inhibit peptidoglycan subunits in cell wall)

Cefazolin (inhibit cell wall synthesis by binding to penicillin-binding proteins & inhibit peptidoglycan synthesis)

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13
Q

Osteochondroma
*What?
*Where?
*Who?
*Presentation

A

*What?: Most common benign bone tumor

*Where?: Found most commonly at the distal femur / proximal tibia

*Males < 25 y/o

*Presentation:
- Painless lesion near join
- Pain worsens w/ activity
- Paresthesias if on or near a nerve

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14
Q

Giant Cell Tumor
*What?
*Where?
*Who?
*Presentation
*Dx
*Histology
*Tx
*Metastasize?

A

*What?
*Where?: Long Bones
*Who?: 20 - 40 y/o females
*Presentation:
- Pain, swelling, inflammation
- Limited ROM at joint

*Dx:
- Bone scans
- X-Ray: Soap Bubble Sign
- CT = cortical thinning + penetration better than x-ray
- MRI helps identify if surrounding tissues are affected

*Histology:
- Multinucleated giant cells

*Tx: Surgical excision

*Metastasis: To lungs

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15
Q

Osteosarcoma
*What?
*Where?
*Who?
*Presentation
*Dx
*Histology
*Tx
*Metastasize?

A

*What?: Primary Bone Tumor
- Can develop after radiation therapy for childhood cancres

*Where?: Distal femur, proximal tibia

*Who?: Males 10-20 yr & > 65 years

*Presentation: Pain lasting several months w/o systemic sx’s

*Dx:
- Elevated Alkaline Phosphatase
- Elevated Lactate Dehydrogenase
- Elevated ESR
- X-Ray
(1) destruction of normal bony pattern
(2) Indistinct bony margins
(3) Mix of radiolucent/radiodense areeas

CODMAN’S TRIANGLE

*Histology
*Tx: Surgery, Chemo

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16
Q

Ewing’s Sarcoma
*What? / Translocation?
*Where?
*Who?
*Presentation
*Dx
*Histology
*Tx

A

*What?: Tumor can occur post-traumatic event
- Translocation: t(11;22)

*Where?: Tibia, fibula, femur, humerus

*Who?: Children 10 - 20 y/o

*Presentation:
- Localized pain/swelling for several weeks & months

*Dx
- X-ray: Shows onion skinning

*Histology

*Tx:
Chemo:
- Doxorubicin: Cardiomyopathy (adverse effect)
- Cyclophosphamide / Ifosfamide: Hemorrhagic Cystitis, toxic metabolite that causes hemorrhagic cystitis = acrolein, treatment of acrolein: Mesna

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17
Q

Rheumatoid arthritis
*What? / Which HLA is it associated with?
*Where?
*Who?
*Presentation
*Dx
*Tx

A

*What?: Chronic inflammatory joint disorder, involves synovial joints
- Associated w/ HLADR4

*Where?:
- Proximal Interphalangeal joints
- MCP’s
- In toes: metatarsol joints

*Who?: Females

*Presentation:
- Symmetrical
- Morning stiffness, improves as day progresses
- Pain, swelling of affected joints
- Myalgia, stiffness, depression, chronic fatigue
- Ulnar Deviation, Swan neck deformity
- Pannus formation

*Dx:
- Anti IgG antibody (IgG antibody)
-Anti Citrullinated peptide antibody

*Tx:
- Inflammatory cytokines: TNF-alpha ; IL-1
- Manage w/ NSAIDs, systemic glucocorticoids, DMARD: Methotrexate (Inhibits DHFR enzyme)

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18
Q

Osteoarthritis
*What?
*Where?
*Who?
*Presentation
*Dx
- Inflammatory markers?
*Tx

A

*What? : Degenerative arthritis, “wear & tear arthritis”

*Where?: Involves hands, feet, knees, hips, spine

*Who?

*Presentation: Heberden’s Nodes (DIP), Bouchard (Proximal-PIP)
- Asymmetric distribution
- Weight bearing joints
- Worse at the end of the day (RA worse in the morning)

*Dx:
- No inflammatory markers
- Synovial fluid = negative
- Imaging = joint space narrowing & bone spurs (from bone rubbing on bone)

*Tx:
- Acetaminophen
- NSAIDs
- Steroids
- Surgery

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19
Q

Psoriatic Arthritis
*What? / HLA Association
*Where?
*Who?
*Presentation
*Dx
- Inflammatory markers?
*Tx

A

*What?: Affects DIP + Psoriatic findings
- Dermatologic findings before arthritic findings
- HLAB27

*Where?

*Who?

*Presentation:
- Dermatologic findings before arthritic findings
- Dermatologic findings: on scalp, nails, intergluteal region
- Nail pitting
-Arthritic findings = Asymmetric
- Visual disturbances: uveitis, conjunctivitis

*Dx
- Imaging: Erosive changes + new bone formation
- Pencil in cup deformity (DIP)

*Tx:
- NSAIDs
- DMARDs
- UV Light

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20
Q

Systemic Lupus Erythematosus (SLE)

*Main Heart causes

*Mnemonic

A

*Can cause Limbann-Sacks endocarditis (mitral valve vegetations) OR inflammation of the pericardial sac

*Mnemonic:
RASH OR PAIN

  • R: Rash (discoid)
  • A: Arthritis
  • S: Serositis
  • H: Hematologic disorders
  • O: Oral / pharyngeal disorders
  • R: Renal Causes
  • P: Photosensitivity
  • A: ANA prescence
  • I: Immuno (anti- dsDNA–specific, Anti-nuclear–specific, anti- Smith, Anti-cardiolipin antibody)
  • N: Neuro Disorders
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21
Q

What are the antibodies found in SLE?

A

(1) Anti-nuclear Ab
(2) Anti ds-DNA Ab
(3) Anti-smith
(4) Anticardiolipin antibody (antiphospholipid ab)

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22
Q

What is falsely elevated in SLE?

A

*PTT
*VDRL & RPR

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23
Q

Tx SLE

A

*NSAIDs
* Steroids
*Hydroxychloroquine

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24
Q

What antibody helps to differentiate between drug induced vs. non-drug induced lupus?

What drugs cause drug-induced lupus?

A

*Anti-histone antibody

*Drug-induced Lupus:
(1) Procainamide
(2) Hydralazine
(3) Penicillamine
(4) Isoniazid
(5) Diltiazem
(6) Minocycline
(7) Quinidine
(8) Methyldopa
(9) Chlorpromazine
(10) Infliximab
(11) Etanercept

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25
Q

Sjogren’s

*What? / HLA Association
*Presentation (triad)
*Dx
- Ab associations
- Histology
*Tx

A

*Autoimmune condition against lacrimal and salivary glands
- HLA-DR3

*Presentation:
(1) keratoconjunctivitis
(2) xerostomia (dry mouth)
(3) arthritis

*Dx:
- Ab associations: Anti-RO/SSA, Anti-La/SSB, anti-nuclear antibodies
- Histology: tons of lymphocytes

*Tx: Pilocarpine, methotrexate, hydroxychloroquine

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26
Q

Behcet’s Disease

*What? / HLA Association
*Presentation
*Dx

*Tx

A

*What? / HLA Association:
- Vascular inflammatory disease that affects a variety of systems throughout the body
- Associated w/ genital + oral disorders
- HLAB51

*Presentation:
- Pseudofolliculitis
- Acneiform lesions
- Pustular eruptions
- Erythema Nodosum
- Visual disturbances: anterir uveitis, retinal vasculitis

*Tx:
- Steroids
- Infliximab (anti-TNF) w/ uveitis

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27
Q

Spondyloarthropathies are associated w/ what haplotype?

A

Associated w/ HLA B27

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28
Q

Ankylosing Spondylitis

*What? / HLA Association

*Presentation

*Dx
- What does diagnosis require?
- Inflamm. markers

*Tx

A

*What? / HLA Association:
- Chronic spinal inflammatory disease
- HLAB27

*Presentation:
- Sacroiliitis
- Chronic back pain, neck pain, gluteal pain, Limited mobility, Pain and mobility improve w/ exercise but not rest
- Nighttime pain usually seen
- Cardiovascular findings
- Visual disturbances
- Inflammatory bowel disease
- Pulmonary disturbances (limited chest expansion)

*Dx
- Diagnosis requires sacroillitis
- Inflammatory markers: Non-specific–ESR, CRP
- Narrowing joint space
- Fusion of vertebrae (bamboo spine)

*Tx
- Exercises to strengthen + loosen up

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29
Q

Reactive Arthritis

*What?

*Presentation

*Dx

*Tx

A

*What?: Arthritis in response to an organism

*Presentation: Arthritis, Conjunctivitis, Urethritis
- “can’t see, can’t pee, can’t climb a tree”

  • Arthritis usually affects more than 1 joint
  • Keratoderma Blennorhagica (lesions on palms + soles)
  • Circinate Balanitis: Inflamm. around glans penis

*Dx
- Organisms: Salmonella, Shigella, Campylobacter, Yersinia, Chlamydia trachomatis, E. Coli, C. Difficile

  • Sx’s develop days to weeks following infection

*Tx: Treat w/ organism specific medication

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30
Q

Scleroderma
*What?

*Presentation
- What is CREST Syndrome

*Dx

*Tx

A

*What?: Systemic autoimmune disease characterized by (1) vasculopathy (2) Fibrosis of skin & other organs

*Presentation:
- Ulcers on fingers
- Telangiectasias
- Pitting (fingertips)
-Depigmentation/hyperpigmentation)
- C: Calcinosis
- R: Raynoud Phenomenon (lack of blood flow to finger tips)
- E: Esophageal dysmotility
- S: Sclerodactylyl
- T: Telangiectasias (small dilated blood vessels)

*Dx
- Anti-centromere ab
- Anti Scl-70 ab
- ANA

*Tx
- Methotrexate

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31
Q

Sarcoidosis
*What?

*Presentation

*Dx

*Tx

A

*What? : Multi-system disorder
- Non-caseating granulomas
- Caused by dysregulated cell-mediated immune response
(Non-caseating granulomas formed by: Th1 CD4+ helper T cells –> secrete IL-2 –> interferon Gamma)

*Who?:
- People 20 - 60 y/o
- More common in black females

*Presentation:
- Affects lungs –> interstital fibrosis –> restrictive lung disease

*Dx
- ^ ACE levels
- Hypercalcemia (due from ^ 1,23-dihydroxy vitamin D levels from increased 1-alpha hydroxylase enzyme activity)
- Dec. PTH secretion
- Bilateral hilar adenopathy on imaging

*Tx:
- Glucocorticoids

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32
Q

Mixed Connective Tissues Disease
- Easy or Hard to diagnose?
- Who get it?
- Antibody?

A
  • Hard to diagnose b/c combines SLE, sclerosis, polymyositis
  • Females in their 20’s
  • Associated w/ anti-U1 RNP ab
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33
Q

Polymyalgia Rheumatica
*What?

*Presentation / Where?

*Who

*Dx

*Tx

A

*What?: Pain in multiple areas: poly

*Presentation / Where?:
- Pain in multiple areas
- Pain in shoulders, neck, torso (pain & stiffness):
- Morning stiffness lasting @ least 30 min.
- Pain in muscles used to wave goodbye, dressing, brushing hair

*Who?: > 50 yrs of age

*Dx:
- ^ ESR & CRP
- MRI: synovial inflammation
- Morning stiffness at least 30 minutes for at least 2 weeks

*Tx:
- Low dose steroids

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34
Q

Fibromyalgia

*What?

*who?

*Presentation

*Where?

*Dx

*Tx

A

*What?:
- Widespread musculoskeletal pain + fatigue
- Can be associated w/ psychiatric / cognitive sx’s

*Who?: Females 20 - 50 y/o

*Presentation

*Where?
- 11/18 areas

*Dx:
- Pain in 11/18 areas for 3 months

*Tx
- Exercise + Higher quality rest
- Duloxetine (SNRI)
- Amitryptiline
- Pregabalin
- Milnacipran

35
Q

Polymyositis & Dermatomyositis

*What?

*Presentation

*Dx

*Tx

A

*What? : Proximal muscle weakness , dermatomyositis = skin eruptions

*Presentation:
- Skin eruptions affects flexors of neck, deltoids, hip flexors
- Gottron’s Papules: discolored/erythematous papules on finger joints

  • Gottron’s sign
  • Facial erythema
  • Upper eyelid swelling
  • Areas of hyper/hypo-pigmentation
  • Epidermal atrophy and telangiectasias

*Dx

*Tx

36
Q

Gout

*What?

*Presentation
- Where does it most commonly affect?
- What does it make?

*Dx

*Tx

A

*What? : Monoarticular arthritis from overproduction or under excretion of uric acid

*Presentation:
- Most commonly affects big toe (podagra)
- Uric acid under the skin = tophus (tophus: caused by uric acid crystals in joint space–precipitated by red meats, alcohol ETOH)

*Dx:
- Crystals = needle shaped + negative birefringent

*Tx:
- Acutely: NSAID’s, Colchicine
- Glucocorticoids
- Allopurinol

37
Q

Pseudogout
*What?

*Where does it most commonly affect?

*Dx

*Tx

A

*What?: Crystals composed of Ca2+ Pyrophosphate

*Presentation:
- Affects knee

*Dx:
- Rhomboid shaped crystals
- Positively birefringent

*Tx:
- NSAIDs, Colchicine, Glucocorticoidss
- Long term treatment: Colchicine

38
Q

Septic Arthritis
*What most commonly causes this?

*Presentation

*Where is this most seen in IV drug users?

*Dx

*Tx

A

*N. Gonorrhea
- Most commonly causes this

*Presentation:
- Fever, chills, IV drug users

*Where in IV drug users?: Sternoclavicular joint, sternomandibular joint, endocarditis

*Dx:
- Joint aspiration to identify organism
- Check for crystals
- Check WBCs

*Tx:
- 3rd generation cephalosporin for gonorrheal infection (ceftriaxone or ceflotaxine)
- Vancomycin

39
Q

Distal radial fracture can happen in… how?

  1. Youth
  2. Older people
  3. Falling?
A
  1. Youth from playing sports
  2. Older population w/ osteoporosis
  3. Fall on outstretched hand
40
Q

Smith fracture

A

Can occur from fall on flexed wrist or blunt trauma to posterior aspect of wrist

41
Q

Ulnar fracture
- Cause

Dx:
Require:

A

Cause: Blunt trauma from medial aspect of forearm

Dx: Xray
Require: immobilization w/ cast

42
Q

Scaphoid Fracture
*Cause?
*Pain where signals this?
- Borders of this region:
>Roof:
>Floor:
>Medial Border:
>Lateral Border:
>Proximal Border:

*Next step

*Worrisome complication:

*What does scaphoid articulate with?

A

*Cause: Falling on outstretched hand (FOOSH)
*Pain in snuff box signals scaphoid fracture
- Snuffbox borders:
>Roof: Skin of hand
>Floor: Scaphoid & Trapezium
>Medial Border: Tendon of extensor pollicus longus
>Lateral Border: tendon of abductor pollicus longus & extensor pollicus brevis
>Proximal Border: styloid process of radius

*Next step: X-RAY

*Worrisome complication: avascular necrosis

*Scaphoid articulates w/ radius

43
Q

What is the vascular supply of the scaphoid bone?

A

Radial artery

44
Q

Mnemonic for bones in hand

A

So long to pinky here comes the thumb!

45
Q

Lunate Dislocation

*Cause?

*How is it distinguished from scaphoid fracture?

A

*Caused by falling on an outstretched hand

*Distinguished from scaphoid by presence of paresthesias from median nerve impingement

46
Q

Carpal Tunnel
*Cause
*Pain where? (Location of pain?)
*Borders of carpal tunnel
- Superiorly
- Inferiorly

*Dx

*Tx

A

*Cause: increased pressure in carpal tunnel

*Pain & paresthesias in the
distribution of median nerve

*Location: thumb, index, middle, lateral half of ring

*Carpal tunnel borders:
- Superiorly: flexor retinaculum (transverse carpal ligament)
- Inferiorly: carpal bones

*Dx: Positive tinel sign & positive phalen test

*Tx: (1) conservative
(2) splint– keeping wrist in slight extension
(3) glucocorticoids
(4) Surgical decompression

47
Q

Rotator Cuff Injury
- What are the muscles? What do they do?

  • Cause of injury?
  • Common Sx’s
  • Dx
  • Tx
A

*SITS
- Supraspinatus: Abducts arm 0 - 15 degrees
- Infraspinatus: lateral/external rotation
- Teres minor: ADducts & external rotates arm
- Subscapularis: ADducts & medial/internal rotation of arm

*Cause: Repetitive throwing

*Sx’s
- Tendon becomes impinged between acromion + head of humerus
- Pain upon abduction
- Dec. ROM (mainly internal rotaiton)
- Crepitations felt over humeral head

*Dx:
- Neer test, can confirm diagnosis
(forcibly elevate arm post pronation)
–pain = Neer sign

*Tx:
- Resting arm
- NSAID’s/Steroid injections
- Arthroscopic surgery

48
Q

Shoulder Dislocation
*Cause?
*What is subluxation?
*Most Common shoulder dislocation
*What nerve is most likely affected?
*Physical findings
*Dx

A

*Cause: dislocation = displacement of humeral head from glenoid fossa
- Forceful external rotation & abduction of arm at shoulder = most responsible for dislocations

*Subluxation: translocation of humeral head relative to glenoid articular surface

*Most common shoulder dislocation: Anterior (Subcoracoid dislocation)

*Axillary nerve wraps around hueral head & at risk of injury with shoulder dislocation = loss of sensation of lateral arm + shoulder

*Physical findings:
- Flattened deltoid prominence
- Protruding acromion
- Anterior axillary fullness
- Sensory loss of skin over deltoid + lateral arm
- Pain immobility

*Dx: X-ray

49
Q

Elbow Injuries
*Lateral Epicondylitis due from repetitive – motions; most commonly occurs in (this sport)

*Medial Epicondylitis due from repetitive – motions; most commonly occurs in (this sport)

A

*Lateral Epicondylitis due from repetitive extension motions; most commonly occurs in tennis

*Medial Epicondylitis due from repetitive flexion motions; most commonly occurs in baseball or golf

50
Q

Quadriceps
- What muscles make it up?
- Action?
- Innervation?
- Blood Supply

A
  • Muscles:
    (1) Rectus femoris
    (2) Vastus Lateralis
    (3) Vastus Intermedius
    (4) Vastus Medialis
  • Action: extension of leg at the knee
  • Innervation: Femoral Nerve
  • Blood supply: femoral artery + branches of deep femoral artery
51
Q

Hamstring
- What muscles make it up?
- Action?
- Innervation?
- Blood Supply

A
  • Muscles:
    (1) Semitendinosus
    (2) Semimembranosus
    (3) Biceps femoris
  • Long head
  • Action:
    Extend at hip + flex at knee
  • Innervation:
    Tibial division of sciatic nerve
  • Blood supply:
    Deep femoral artery
52
Q

Hip Flexors (5)

A

(1) Sartorious
(2) Rectus Femoris
(3) Pectineus
(4) Psoas
(5) Iliacus

53
Q

Anterior Compartment of leg
- Muscles
- Blood Supply
- Major Action
- Nerve

A
  1. Tibialis Anterior
  2. Extensor Digitorum Longus (EDL)
  3. Extensor Hallucis Longus
  4. Fibularis tertius
    (peroneus tertius)
    *muscle belly often fused w/ EDL
    *but tendon inserts in diff. location

*4 muscles

*Blood Supply:
*Ant. Tibial artery

Major action:
*ext. of toes &/or dorsiflexion of foot at ankle

Nerve:
*Deep fibular n.

54
Q

Lateral Compartment
- Muscles
- Blood Supply
- Major Action
- Nerve

A
  1. Fibularis (peroneus) longus
    - Inserts on plantar surface of foot
    - 1st metatarsal & medial cuneiform
  2. Fibularis (peroneus) brevis
    - Inserts on dorsum of 5th metatarsal

*2 muscles
both pass posterior to lateral malleolus at ankle
- Tendons bound down by sup./inf. Retinacula

Blood:
- Fibular artery
(branch of posterior tibial)

Action:
- Eversion of the foot
(turn plantar surface laterally)

- Weak plantarflexion at ankle (tilting foot inferiorly at the ankle)

Innervation:
- Superficial fibular

55
Q

Posterior Compartment Superficial

  • Muscles
  • Blood Supply
  • Major Action
  • Nerve
A

*3 muscles, superficially
transverse intermuscular septum divides posterior compartment of leg into a superficial/deep group

  1. Gastrocnemius
    - lateral/medial head
  2. Soleus
    - tendon of gastrocnemius & soleus unite inf. To form the calcaneal tendon
    (Achilles tendon)

*some consider gastrocnemius/soleus: triceps surae

  1. Plantaris
    - Small weak muscle w/ long tendon
    - Like palmaris longus in upper limb

Blood:
- Post. Tibial artery
- Fibular artery

Action:
- Plantarflexion at ankle
(gastrocnemius flexes at knee)
“Foot in pond”

Innervation:
- Tibial Nerve

56
Q

Posterior Compartment Deep
- Muscles
- Blood Supply
- Major Action
- Nerve

A

*4 muscles, deep
1. Flexor hallucis longus

  1. Flexor digitorum longus
  2. Tibialis posterior
    - Inverts food (turns plantar surface medially)
  3. Popliteus
    • Crosses the knee
      ○ Only muscle in post. compartment
    • Only muscle that does not cross the ankle

Blood:
- Posterior tibial artery
(branch of posterior tibial)
- Fibular artery

Action:
for all muscles except popliteus
- Flexion of toes
- Plantarflexion at ankle
(gastrocnemius flexes at knee)

Innervation:
- Tibial Nerve
○ Gives off medial sural cutaneous n.
§ Then passes deep to arch of soleus
□ Ends as medial / lateral plantar nerve

57
Q

What ligament is most likely injured in an ankle sprain?

A

Anterior talofibular ligament

58
Q

What nerve travels around lateral condyle in the leg?
(1) Describe it’s course
(2) Injury
(3) Branches

A

Common Fibular Nerve (Peroneal Nerve)
(1) Courses laterally around neck of fibula around lateral condyle

(2) Susceptible to trauma from lateral blows to knee, tight casts
- Foot drop

  • Peroneal neuropathy: ext. bedrest, knee hyperflexion
  • Peripheral neuropathy: obstetric stirrups, ballet dancers, crossing the legs

(3) Superficial fibular nerve + deep fibular branches
- Fibular n : supplies muscles of lateral compartment of leg

  • Deep fibular n: supplies muscles of anterior compartment of leg–dorsiflexion of foot/extension of toes
59
Q

Trendelenburg gait
- What?
- What side is affected?

A
  • What?: Abnormal gait caused by weakness of abductor muscles of lower limb, gluteus medius, gluteus minimus
  • What side is affect?: Contralateral side (injured side opposite of pelvic sag, patient picks up foot off the ground, pelvis sags on opposite side of injury)
60
Q

Sciatica
(AKA sciatic neuropathy)
*What?
*Cause
*Signs & Sx’s
*Dx
*Tx

A

*What?: Result of irritation of the sciatic nerve or one of its roots
- Due to injury at L5 or S1

*Cause:
- Herniation
- Spinal canal stenosis
- Bone spurs
- Piriformis syndrome (inflammed piriformis)

*Signs & Sx’s:
- Weakness of posterior thigh
- Weakness of muscles distal to the knee
- Shooting pain from posterior thigh/leg to foot
- Post. thigh pain and/or sensory diminishment
- Pain or loss of sensation in calk
- Loss of sensation on plantar surface of foot
- Diminished ankle reflex due to S1 nerve root (weakened plantar flexion

*Dx:
- Physical exam
- Neurologic exam
- Imaging if needed

*Tx:
- Muscle relaxants &/or opioids
- Long-term management w/ NSAIDs, Acetaminophen

61
Q

Hip Dislocation
- What type of dislocation?
- Injures what nerve?
- Dx

A
  • Most likely posterior dislocation (affected side appears shortened & internally rotated)
  • Anterior dislocation (affected side: not shortened, externally rotated)

*Dx:
- X-Ray
- Neurologic examination
- Immediate reduction under sedation
- May req. open reduction
- Post. dislocation
- Pt’s should avoid weight bearing activity for a min. of 3 weeks

62
Q

Femoral Neck Fracture
- What caused it?
- Sx’s
- What nerve is at risk & what is a compliation?

A

*What caused it:
- Older pt’s suffering from osteoporosis

*Sx’s: Severe hip/groin pain upon movement
(leg usually externally rotated on presentation)

*Nerve at risk: medial femoral circumflex artery
- Complication: avascular necrosis of femoral head (may be associated w/ sickle cell disease, SLE, steroid therapy, alcoholism)

63
Q

Anterior Cruciate Ligament (ACL)
- Where does it attach?
- What does it help do?
- Who are ACL tears more common in?
- Cause?
- Sx’s?
- Dx
- Tx

A

*Ant. aspect of tibia

*Helps to stabilize the knee during extension

*ACL tears are more common in women due from muscular imbalance between ant. & post. muscles of the thigh
- Athletes

*Cause:
- Landing on stiff leg
- Rapid deceleration followed by acute directional changes ^ risk of injury

*Sx’s
- Pain & Swelling
- Non-stability in knee
- Popping sound on injury

*Dx:
- Anterior drawer sign (90 degrees)
- Lachman test (30 degrees)
- MRI

*Tx: Surgery

64
Q

Posterior Cruciate Ligament
*Attachment
*Purpose
*Cause
*Dx

A

*Attaches to posterior aspect of intercondylar area of tibia

*Purpose:
- Prevents post. movement of femur relative to tibia, when knee flexes

*Cause: dashboard injury

*Dx: posterior drawer test

65
Q

Medial Collateral Ligament
*Is this the most commonly injured collateral ligament?
*Cause

A

*YES!

*Cause: direct blow to lateral aspect of knee

66
Q

Unhappy triad

A

(1) ACL
(2) Medial Collateral
(3) Medial meniscus

67
Q

Mnemonic to remember which is more medial: tibia or fibula?

A

Tibia = towards the middle

68
Q

Meniscal Tears
*Who?
*Cause?
*Sx’s

A

*Who?: Most commonly in older people w/ joint degeneration

*Cause?: Planted foot and rapid change in direction

*Sx’s: knee unsteadiness, pain, swelling, clicking, locking during mostion

69
Q

Bursitis
*What?
*Cause?

A

*What? Inflammation of fluid filled bursa (counteracts joint friction)

*Cause:
- Associated w/ constant repetitive motion, maintaining long-term positions such as kneeling

70
Q

Baker’s Cyst
*What?
*Cause?
*Which specific bursa is affected?

A

*What?: Cyst formation in popliteal fossa

*Cause?: Knee injuries, inflammatory arthritis, degenerative disease

*Specific bursa affected:
- Gastrocnemius semimembranosus bursa–lies between 2 muscles on medial side of fossa

71
Q

Orbital blowout fracture
*Cause?

*What is it called when surrounding bones are affected?

A

*Cause?: Blunt trauma to face
- increase pressure posteriorly in orbit causes weakest bones to fracture

*LeFort Fracture: Maxillary bones + surrounding structure

72
Q

Basilar Skull fracture
*What?
*Most commonly due to?
*Clinical Signs

A

*What?: trauma to at least 1 of 5 bones that make up base of skull (sphenoid , occipital cribiform plate of ethmoid bone, orbital plate of frontal pone, petrous or squamous portion of temporal bone)

*Temporal Bone Injury

*Signs:
- Battle’s sign: bruising of mastoid bone – posterior auricular artery = branch of carotid a.

  • Periorbital Ecchymosis, Raccoon Eye
  • CSF rhinorrhea
  • Hemotympanum (blood behind tympanic membrane)
73
Q

Type-1 Muscle Fibers
*What are they used for?
*What type of respiration?
*What color are they?

A

*Used for a long-term, sustained work

*Aerobic Respiration. Rich in mitochondria, have little energy

*Dark, b/c very rich in mitochondria

74
Q

Type 2 Fast twitch
*What are they used for?
*What types, how fast to they fatigue?
*What color are they?

A

*What are they used for?: Rapid, forceful movements for short period of time

*Different types:
- Type 2a: moderately fast, fairly resistant to fatigue, tons of mitochondria

  • Type 2x: faster than 2a, fatigue faster than 2a, mid-range mitochondria
  • Type 2b: fastest contraction speed, fatigue rapidly, low amount of mitochondria

*What color are they?: lighter

75
Q

What gives striated appearance to muscles?

A

*Sarcomeres

76
Q

*Cardiac Muscle
- Does it have sarcomeres?
- Does it use intracellular Ca2+?
- Does it have syncytial and autonomic activity?
- Does it contain gap junctions?

A
  • Does it have sarcomeres?: Yes
  • Does it use intracellular Ca2+? Yes, uses extracellular calcium to trigger intracellular release, extracellular ca2+ flows into T-tubules
  • Does it have syncytial and autonomic activity?
  • complete syncytial & autonomic activity
  • Does it contain gap junctions?: Yes
77
Q

*Does smooth muscle have striations?
- What is the job of intracellular & extracellular Ca2+
- Does it have autonomics? And syncytial activity?
- Does it contain troponin?

A

*Smooth muscle does not have striations because no sarcomeres.
- Intracellular Ca2+ needed for contraction,
- Extracellular Ca2+ needed to stimulate 2nd messenger system

*Has full autonomics and syncytial activity

*Does NOT contain troponin

78
Q

What is rigor mortis?

A

Rigor Mortis: without ATP myosin head remains bound to actin filaments

79
Q

What does a smooth muscle contraction use?
- Ca2+?
- What complex?

A

*Uses two sources of calcium
*Uses calmodulin (calcium binding protein) & myosin light chain kinase

80
Q

Golgi Tendon Organ
- Where is it located?
- Role?
- Pathway?

A

*Located in the muscle
*Role: Watch tesnion w/in muscle
- Allows for maximal muscle contraction only for 1 second

*Pathway:
1. Golgi tendon organ will detect tension applied to the tendon
2. Sensory neurons send signal to spine
3. Sensory neurons synapse with inhibitory interneurons
(synapse w/ alpha motor neurons)
4. Alpha motor neuron inhibition leads to muscle relaxation and relief of tension

81
Q

Muscle Strain
- Tx

A

Overstretching of muscle
- Tx: NSAIDS &/or muscle relaxants (baclofen, cyclobensaprine)

82
Q

Muscle Sprain
- Tx Mnemonic

A

Tearing of a tendon via XS stretching results in muscular sprain
- Tx: RICE: rest, ice, compression, elevation

83
Q

What causes malignant hypertheria?

A

Defects in ryanodine receptor, associated w/anesthetics (ex. succinylcholine)

84
Q
A

USMLE Success (6 decks)

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