Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

USMLE First Aid Step 1 (2015) > MSK, Skin, and Connective Tissue (415-446) > Flashcards

MSK, Skin, and Connective Tissue (415-446) Flashcards

You may prefer our related Brainscape-certified flashcards:
USMLE® Step 1 flashcards
1
Q

With patient supine, bending knee at 90-degree
angle, inc. anterior gliding of tibia due to ACL
injury.

A

Anterior Drawer Sign

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

With patient supine, bending knee at 90-degree
angle, inc. posterior gliding of tibia due to PCL
injury.

A

Posterior drawer sign

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

With patient supine and knee either extended
or at ∼ 30-degree angle, lateral (valgus) force
-> medial space widening of tibia -> MCL
injury.

A

Abnormal passive

abduction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

With patient supine and knee either extended
or at ~ 30-degree angle, medial (varus) force
-> lateral space widening of tibia -> LCL
injury.

A

Abnormal passive

adduction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

With patient supine and knee internally and
externally rotated during range of motion:
- Pain, “popping” on external rotation -> medial meniscal tear
- Pain, “popping” on internal rotation -> lateral meniscal tear

A

McMurray test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Common injury in contact sports due to lateral
force applied to a planted leg. Classically,
consists of damage to the ACL, MCL, and
medial meniscus (attached to MCL); however,
lateral meniscus injury is more common.
Presents with acute knee pain and signs of
joint injury/instability.

A

“Unhappy triad”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

“Housemaid’s knee”. Can be caused by repeated trauma or pressure from extensive kneeling.

A

Prepatellar bursitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Popliteal fluid collection commonly related to chronic joint disease.

A

Baker cyst

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Rotator cuff muscles

A

Shoulder muscles that form the rotator cuff:
- Supraspinatus (suprascapular nerve)—
abducts arm initially (before the action of the deltoid); most common rotator cuff
injury, assessed by “empty/full can” test.
- Infraspinatus (suprascapular nerve)—laterally rotates arm; pitching injury.
- teres minor (axillary nerve)—adducts and laterally rotates arm.
- Subscapularis (upper and lower subscapular nerves)—medially rotates and adducts arm.
Innervated primarily by C5-C6.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Repetitive flexion (forehand shots) or idiopathic -> pain near medial epicondyle.

A

Medial epicondylitis

golfer’s elbow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Repetitive extension (backhand shots) or idiopathic -> pain near lateral epicondyle.

A

Lateral epicondylitis

tennis elbow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Wrist bones

A

Scaphoid, Lunate, Triquetrum, Pisiform, Hamate, Capitate, Trapezoid, Trapezium. (So Long To Pinky, Here Comes The Thumb).
Scaphoid (palpated in anatomic snuff box) is the most commonly fractured carpal bone and is prone to avascular necrosis owing to retrograde blood supply.
Dislocation of lunate may cause acute carpal
tunnel syndrome.
A fall on an outstretched hand that damages the hook of the hamate can cause ulnar nerve injury.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Entrapment of median nerve in carpal tunnel; nerve compression -> paresthesia, pain, and numbness in distribution of median nerve. Associated with pregnancy, rheumatoid arthritis, hypothyroidism; may be associated with repetitive use.

A

Carpal tunnel

syndrome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Compression of ulnar nerve at wrist or hand. Classically seen in cyclists due to pressure from handlebars.

A

Guyon canal

syndrome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Fractured surgical neck of humerus; anterior

dislocation of humerus

A

Axillary (C5-C6)

Flattened deltoid
Loss of arm abduction at shoulder (> 15 degrees)
Loss of sensation over deltoid muscle and lateral
arm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Loss of forearm flexion and supination

Loss of sensation over lateral forearm

A

Musculocutaneous
(C5-C7)

Upper trunk compression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Midshaft fracture of humerus; compression of
axilla, e.g., due to crutches or sleeping with
arm over chair (“Saturday night palsy”)

A

Radial (C5-T1)

Wrist drop: loss of elbow, wrist, and finger
extension
Dec. grip strength (wrist extension necessary for
maximal action of flexors)
Loss of sensation over posterior arm/forearm and
dorsal hand

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

“Ape hand” and “Pope’s blessing”
Loss of wrist flexion, flexion of lateral fingers,
thumb opposition, lumbricals of 2nd and 3rd
digits
Loss of sensation over thenar eminence and
dorsal and palmar aspects of lateral 3 1⁄2 fingers
with proximal lesion
Tinel sign (tingling on percussion) in carpal
tunnel syndrome

A

Median (C5-T1)

Supracondylar fracture of humerus (proximal
lesion); carpal tunnel syndrome and wrist
laceration (distal lesion)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Fracture of medial epicondyle of humerus
“funny bone” (proximal lesion); fractured hook
of hamate (distal lesion)

A

Ulnar (C8-T1)

“Ulnar claw” on digit extension
Radial deviation of wrist upon flexion (proximal
lesion)
Loss of wrist flexion, flexion of medial fingers,
abduction and adduction of fingers (interossei),
actions of medial 2 lumbrical muscles
Loss of sensation over medial 1 1⁄2 fingers
including hypothenar eminence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Superficial laceration of palm

A 
Recurrent branch of
median nerve (C5-T1)

“Ape hand”
Loss of thenar muscle group: opposition,
abduction, and flexion of thumb
No loss of sensation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Infants—lateral
traction on neck
during delivery
Adults—trauma

A

Erb palsy (“waiter’s tip”)

Traction or tear of upper
(“Erb-er”) trunk: C5-C6 roots

Deltoid, supraspinatus
Abduction (arm hangs by side)

Infraspinatus Lateral rotation (arm medially rotated)

Biceps brachii Flexion, supination (arm extended and pronated)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Traction or tear
of lower trunk:
C8-T1 root

A

Klumpke palsy

Infants—upward
force on arm
during delivery
Adults—trauma
(e.g., grabbing
a tree branch to
break a fall)
Intrinsic hand
muscles:
lumbricals,
interossei,
thenar,
hypothenar
Total claw hand:
lumbricals normally
flex MCP joints and
extend DIP and PIP
joints
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q 
Atrophy of intrinsic
hand muscles;
ischemia, pain,
and edema
due to vascular
compression
A

Thoracic outlet
syndrome

Compression of lower trunk
and subclavian vessels

Cervical rib,
Pancoast tumor

Intrinsic hand
muscles: lumbricals, interossei, thenar,
hypothenar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Axillary node
dissection after
mastectomy,
stab wounds

A

Winged scapula

Lesion of long
thoracic nerve

Serratus anterior

Inability to anchor
scapula to thoracic
cage -> cannot
abduct arm above
horizontal position
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Seen best with distal lesions of median or ulnar nerves.

Remaining extrinsic flexors
of the digits exaggerate the loss of the lumbricals -> fingers extend at MCP, flex at DIP and PIP
joints.

A

Clawing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

“Ulnar claw”

A

Extending fingers/at
rest

Distal ulnar nerve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

“Pope’s blessing”

A

Making a fist

Proximal median
nerve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

“Median claw”

A

Extending fingers/at
rest

Distal median nerve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

“OK gesture”
(with digits 1–3
flexed)

A

Making a fist

Proximal ulnar nerve

30
Q

Atrophy of the thenar eminence (unopposable thumb -> “ape hand”

vs

Atrophy of the hypothenar eminence

A

Thenar: Median nerve
Hypothenar: Ulnar nerve

31
Q

Thenar (median)

A

Opponens pollicis, Abductor
pollicis brevis, Flexor pollicis brevis, superficial
head (deep head by ulnar nerve).

Oppose, Abduct, and Flex (OAF).

32
Q

Hypothenar (ulnar)

A

Opponens digiti minimi,
Abductor digiti minimi, Flexor digiti minimi
brevis.

Oppose, Abduct, and Flex (OAF).

33
Q

Dorsal interossei

A

abduct the fingers

DAB = Dorsals ABduct.
PAD = Palmars ADduct.
34
Q

Palmar interossei

A

adduct the fingers.

DAB = Dorsals ABduct.
PAD = Palmars ADduct.
35
Q

Lumbricals

A

flex at the MCP joint, extend PIP and DIP joints.

36
Q

Pelvic surgery

Dec. thigh sensation (medial) and dec. adduction.

A

Obturator (L2–L4)

37
Q

Pelvic fracture

Dec. thigh flexion and leg extension.

A

Femoral (L2–L4)

38
Q

Trauma or compression of lateral aspect of leg,

fibular neck fracture

A

Common peroneal
(L4–S2)

Foot drop—inverted and plantarflexed at rest,
loss of eversion and dorsiflexion. “Steppage
gait.” Loss of sensation on dorsum of foot.

PED = Peroneal Everts and Dorsiflexes; if injured, foot dropPED.

39
Q 
Knee trauma, Baker cyst (proximal lesion); tarsal
tunnel syndrome (distal lesion)
A

Tibial (L4–S3)

Inability to curl toes and loss of sensation on sole
of foot. In proximal lesions, foot everted at rest
with loss of inversion and plantarflexion.

TIP = Tibial Inverts and Plantarflexes; if injured, can’t stand on TIPtoes.

40
Q

Iatrogenic injury during intramuscular injection

to upper medial gluteal region

A

Superior gluteal
(L4–S1)

Trendelenburg sign/gait—pelvis tilts because
weight-bearing leg cannot maintain alignment
of pelvis through hip abduction (superior
nerve -> medius and minimus). Lesion is
contralateral to the side of the hip that drops,
ipsilateral to extremity on which the patient
stands.

41
Q

Posterior hip dislocation

A

Inferior gluteal
(L5–S2)

Difficulty climbing stairs, rising from seated

position. Loss of hip extension (inferior nerve
- > maximus).

42
Q

Superior gluteal nerve innervates —–. Inferior gluteal nerve innervates —–.

A

Superior gluteal nerve innervates gluteus medius and minimus.

Inferior gluteal nerve innervates gluteus maximus.

43
Q

Sciatic nerve (L4–S3) innervates —–, splits into —–.

A

Sciatic nerve (L4–S3) innervates posterior thigh, splits into common peroneal and tibial nerves.

44
Q 
Pudendal nerve (S2–S4) innervates -----. Can be blocked with local anesthetic during childbirth using the -----
as a landmark for injection.
A 
Pudendal nerve (S2–S4) innervates perineum. Can be blocked with local anesthetic during childbirth using the ischial spine
as a landmark for injection.
45
Q

Paresthesias and weakness in distribution of specific lumbar or sacral spinal nerves.
Often due to —– in which the nerve association with the —–
vertebral body is impinged

A

Paresthesias and weakness in distribution of specific lumbar or sacral spinal nerves. Often due to intervertebral disc herniation in which the nerve association with the inferior
vertebral body is impinged (e.g., herniation of L3–L4 disc affects the L4 spinal nerve).

46
Q

Intervertebral discs generally herniate —– due to the thin —– and thicker —– along the midline of the vertebral bodies.

A

Intervertebral discs generally herniate posterolaterally, due to the thin posterior
longitudinal ligament and thicker anterior longitudinal ligament along the midline of the vertebral bodies.

47
Q

L3–L4

Weakness of?

A

Weakness of knee extension, Dec. patellar reflex

48
Q

L4–L5

Weakness of?

A

Weakness of dorsiflexion, difficulty in heelwalking

49
Q

L5–S1

Weakness of?

A

Weakness of plantarflexion, difficulty in toewalking,

Dec. Achilles reflex

50
Q

Neurovascular pairing

A

Nerves and arteries are frequently named together by the bones/regions with which they are
associated. Some exceptions (see other card)

51
Q

Exceptions to the neurovascular pairing rule.

Axilla/lateral thorax

A

Long thoracic n.

Lateral thoracic a.

52
Q

Exceptions to the neurovascular pairing rule.

Surgical neck of
humerus

A

Axillary n.

Posterior circumflex a.

53
Q

Exceptions to the neurovascular pairing rule.

Midshaft of humerus

A

Radial n.

Deep brachial a.

54
Q

Exceptions to the neurovascular pairing rule.

Distal humerus/
cubital fossa

A

Median n.

Brachial a.

55
Q

Exceptions to the neurovascular pairing rule.

Popliteal fossa

A

Tibial n.

Popliteal a.

56
Q

Exceptions to the neurovascular pairing rule.

Posterior to medial
malleolus

A

Tibial n.

Posterior tibial a.

57
Q

Muscle Physiology

  1. Action potential depolarization opens
    - —- voltage-gated —– channels, inducing neurotransmitter release.
  2. Postsynaptic ligand binding leads to —– in the ——.
A
  1. Action potential depolarization opens
    presynaptic voltage-gated Ca2+ channels,
    inducing neurotransmitter release.
  2. Postsynaptic ligand binding leads to muscle
    cell depolarization in the motor end plate.
58
Q

Muscle Physiology

  1. Depolarization travels along muscle cell and
    down the —–.
  2. Depolarization of the voltage-sensitive —– receptor, mechanically coupled to the —– receptor on the sarcoplasmic reticulum, induces a conformational change, causing —– from sarcoplasmic reticulum.
A
  1. Depolarization travels along muscle cell and
    down the T-tubule.
  2. Depolarization of the voltage-sensitive dihydropyridine receptor, mechanically coupled to the ryanodine receptor on
    the sarcoplasmic reticulum, induces a conformational change, causing Ca2+ release from sarcoplasmic reticulum.
59
Q

Muscle Physiology

  1. Released Ca2+ binds to —–, causing
    a conformational change that moves —– out of the myosin-binding groove on —–.
  2. Myosin releases bound ADP and inorganic PO43 –> displacement of —– on the —– (power stroke). Contraction
    results in shortening of —– and —– bands and between —– lines (—– shrinkage), but the —– band remains the same length.
A
  1. Released Ca2+ binds to troponin C, causing
    a conformational change that moves tropomyosin out of the myosin-binding groove on actin filaments.
  2. Myosin releases bound ADP and inorganic
    PO43 –> displacement of myosin on the actin filament (power stroke). Contraction
    results in shortening of H and I bands and between Z lines (HIZ shrinkage), but the
    A band remains the same length (A band is Always the same length).
60
Q

Muscle Physiology

  1. Binding of a new ATP molecule causes —– of myosin head from actin filament. Hydrolysis of bound ATP -> ADP, —– head adopts high-energy position (“cocked”) for the next contraction cycle.
A
  1. Binding of a new ATP molecule causes detachment of myosin head from actin
    filament. Hydrolysis of bound ATP -> ADP, myosin head adopts high-energy position
    (“cocked”) for the next contraction cycle.
61
Q

Muscle Physiology

T-tubules (extensions of —– juxtaposed with —–) are part of the —–.

In skeletal muscle, —– T-tubule + —– terminal cisternae = triad.

In cardiac muscle, —– T-tubule + —– terminal cisternae = diad.

A

T-tubules (extensions of plasma membrane juxtaposed with terminal cisternae) are part of the sarcoplasmic reticulum.

In skeletal muscle, 1 T-tubule + 2 terminal cisternae = triad.

In cardiac muscle, 1 T-tubule + 1 terminal cisternae = diad.

62
Q

Muscle Physiology

Z-line - ?

I-band - ? only

A-band - ?

H-band - ? only

M-line - ?

A

Z-line - sarcomere between z-lines, actin anchor

I-band - Actin only

A-band - Actin, Myosin

H-band - Myosin only

M-line - Myosin anchor

63
Q

Slow twitch; red fibers resulting from inc. mitochondria and myoglobin concentration (inc. oxidative phosphorylation) -> sustained contraction.

A

Type 1 muscle

Think “1 slow red ox.”

64
Q

Type 2 muscle

A

Fast twitch; white fibers resulting from dec. mitochondria and myoglobin concentration (dec. anaerobic glycolysis); weight training results in hypertrophy of fast-twitch muscle fibers.

65
Q

Smooth Muscle Contraction

  1. AP causes membrane depolarization
  2. Activation of —–
  3. Release of —– intracellularly
  4. Increased formation of —–
  5. Increased —–
  6. Increased —–
  7. Contraction via Cross bridging
A
  1. AP causes membrane depolarization
  2. Activation of L-type voltage-gated Ca2+ channel
  3. Release of calcium intracellularly
  4. Increased formation of Ca2+-Calmodulin complexes
  5. Increased Myosin-light-chain-kinase (MLCK)
  6. Increased Myosin-P and Actin
  7. Contraction via Cross bridging

Increased Ca2+ = contraction

66
Q

Smooth Muscle Relaxation

  2. Increased —–
  3. Increased conversion of —– to —–
  4. —– increases —–
  5. Increased —–
  6. Relaxation
A
  1. Nitric Oxide
  2. Increased Guanylate Cyclase
  3. Increased conversion of GTP to cGMP
  4. cGMP increases Myosin-light-chain-phosphatase (MLCP)
  5. Increased Myosin + actin
  6. Relaxation

NO2 = Relaxation

67
Q

Bone formation

Endochondral
ossification

A

Bones of axial and appendicular skeleton and base of skull.

Cartilaginous model of bone is first made by chondrocytes. Osteoclasts and osteoblasts later replace with woven bone and then remodel to lamellar bone.

In adults, woven bone occurs after fractures and in Paget disease.

68
Q

Bone formation

Bones of calvarium and facial bones. Woven bone formed directly without cartilage. Later remodeled to lamellar bone.

A

Membranous

ossification

69
Q

Cell biology of bone

Build bone by secreting collagen and catalyzing mineralization. Differentiate from mesenchymal
stem cells in periosteum.

A

Osteoblasts

70
Q

Cell biology of bone

Osteoclasts

A

Multinucleated cells that dissolve bone by secreting acid and collagenases. Differentiate from
monocytes, macrophages.

71
Q

Cell biology of bone

Parathyroid hormone

At low, intermittent levels, exerts —– effects on osteoblasts and osteoclasts (indirect).

Chronically inc. PTH levels (1° hyperparathyroidism) cause —– effects (osteitis fibrosa cystica).

A

At low, intermittent levels, exerts anabolic effects (building bone) on osteoblasts and osteoclasts (indirect).

Chronically inc. PTH levels (1° hyperparathyroidism) cause catabolic effects (osteitis
fibrosa cystica).

72
Q

Cell biology of bone

Estrogen

Estrogen inhibits —– in —– and induces —– in —–.

Estrogen deficiency (surgical or postmenopausal), excess cycles of remodeling, and
bone resorption lead to -----.
A

Estrogen inhibits apoptosis in bone-forming osteoblasts and induces apoptosis in bone-resorbing osteoclasts.

Estrogen deficiency (surgical or postmenopausal), excess cycles of remodeling, and
bone resorption lead to osteoporosis.

USMLE First Aid Step 1 (2015) (1 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions