Clinical Sciences Flashcards
Apoptosis, programmed cell death, is the only mechanism that would precipitate cure without unacceptable adverse effect. Differentiation, mutagenesis and senescence do not cause cell death, whereas necrosis causes premature cell death by autolysis and has adverse clinical effects.
Dermatomes of the head
Trigeminal nerve (CN V)
V1: ophthalmic branch – the lateral aspect of the forehead
V2: maxillary branch – the cheek
V3: mandibular branch – the lower jaw (avoid the angle of the mandible as it is supplied by C2/C3)
Other
C2: 1-2 cm lateral to the occipital protuberance
C3: the supraclavicular fossa in the midclavicular line.
Dermatomes of the upper limb
C4: over the acromioclavicular joint.
C5: the lateral aspect of the lower edge of the deltoid muscle (known as the “regimental badge”).
C6: the palmar side of the thumb.
C7: the palmar side of the middle finger.
C8: the palmar side of the little finger.
T1: the medial aspect antecubital fossa, proximal to the medial epicondyle of the humerus.
Dermatomes of the torso
T2: the apex of the axilla.
T3: the intersection of the midclavicular line and third intercostal space.
T4: the intersection of the midclavicular line and the fourth intercostal space at the level of the nipples.
T5: the intersection of the midclavicular line and the fifth intercostal space, horizontally located midway between the level of the nipples and the level of the xiphoid process.
T6: the intersection of the midclavicular line and the horizontal level of the xiphoid process.
T7: the intersection of the midclavicular line and the horizontal level at one quarter the distance between the level of the xiphoid process and the level of the umbilicus.
T8: the intersection of the midclavicular line and the horizontal level at one half the distance between the level of the xiphoid process and the level of the umbilicus.
T9: the intersection of the midclavicular line and the horizontal level at three-quarters of the distance between the level of the xiphoid process and the level of the umbilicus.
T10: the intersection of the midclavicular line, at the horizontal level of the umbilicus.
T11: the intersection of the midclavicular line, at the horizontal level midway between the level of the umbilicus and the inguinal ligament.
T12: the intersection of the midclavicular line and the midpoint of the inguinal ligament.
Dermatomes of the lower limb
L1: the inguinal region and the very top of the medial thigh.
L2: the middle and lateral aspect of the anterior thigh.
L3: the medial epicondyle of the femur.
L4: the medial malleolus.
L5: the dorsum of the foot at the third metatarsophalangeal joint.
S1: the lateral aspect of the calcaneus.
S2: at the midpoint of the popliteal fossa.
S3: at the horizontal gluteal crease (the horizontal crease formed by the inferior aspect of the buttocks and the posterior upper thigh).
S4/5: the perianal area.
Myotomes
C4: shoulder shrugs
C5: shoulder abduction and external rotation; elbow flexion
C6: wrist extension
C7: elbow extension and wrist flexion
C8: thumb extension and finger flexion
T1: finger abduction
L2: hip flexion
L3: knee extension
L4: ankle dorsiflexion
L5: big toe extension
S1: ankle plantarflexion
S4: bladder and rectum motor supply
Clinical Trials (Human Studies)
Phase 0 (Exploratory)
Small scale: 10–15 healthy volunteers.
Microdosing: Subtherapeutic doses to study pharmacokinetics.
Goal: Early go/no-go decision for Phase I.
Phase I (Safety & Dosing)
Participants: 20–100 healthy volunteers (or patients, e.g., in cancer trials).
Focus:
Safety (side effects, maximum tolerated dose).
Pharmacokinetics (how the body absorbs, metabolizes, excretes the drug).
Duration: Weeks to months.
Phase II (Efficacy & Side Effects)
Participants: 100–300 patients with the target disease.
Focus:
Preliminary efficacy (does it work?).
Optimal dosing (balance of benefit vs. side effects).
Design: Often randomized, placebo-controlled.
Outcome: Identifies promising treatments for Phase III.
Phase III (Large-Scale Efficacy & Monitoring)
Participants: 300–3,000+ patients across multiple centers.
Focus:
Confirm efficacy vs. standard treatment/placebo.
Monitor long-term/adverse effects.
Design: Randomized, double-blind, multicenter.
Regulatory submission: Data submitted to FDA/EMA for approval.
Phase IV (Post-Marketing Surveillance)
After approval, in the general population.
Goals:
Real-world safety (rare/long-term side effects).
New uses (off-label applications).
Comparative effectiveness (vs. other treatments).
RRR answers:
“What percentage reduction in risk does the treatment provide relative to the control group?”
RRR = (Risk in Control − Risk in Treatment )/ Risk in Control
Risk in Control (CER) = Events in Control / Total in Control
Risk in Treatment (EER) = Events in Treatment / Total in Treatment
Relative Risk (RR) = EER / CER
