HIGH-YIELD MEDICAL NOTES
USMLE Step 1 Complete Review
2025–2026 Edition
Anatomy · Physiology · Biochemistry · Pharmacology
Subjects Covered
Pathology · Microbiology · Immunology
Total Pages ~50 pages of exam-ready notes
Format Topic summaries · Tables · Mnemonics · High-yield callouts
Best Used For USMLE Step 1 · COMLEX Level 1 · Medical Finals
© 2025 MedNotes Pro | For educational use only | Not a substitute for clinical judgement
, TABLE OF CONTENTS
1. Anatomy & Embryology
3
2. Physiology
8
3. Biochemistry & Genetics
14
4. Pharmacology
20
5. Pathology
27
6. Microbiology & Infectious Disease
34
7. Immunology
40
8. Rapid Review: 100 Must-Know Facts
44
, Chapter 1
Anatomy & Embryology
1.1 Brachial Plexus — Roots, Trunks, Divisions, Cords, Branches
Roots: C5–T1 | Mnemonic: 'Real Texans Drink Cold Beer' (Roots, Trunks, Divisions, Cords,
Branches)
Nerve Root(s) Key Action / Injury Pattern
Deltoid atrophy; loss of shoulder
Axillary C5, C6
abduction (surgical neck # humerus)
Weak elbow flexion & supination;
Musculocutaneous C5–C7
lateral forearm sensory loss
Wrist drop; loss of finger extension
Radial C5–T1 (Saturday night palsy, humeral shaft
#)
Ape hand; carpal tunnel; loss of
Median C6–T1
thenar muscles
Claw hand; intrinsic muscle wasting;
Ulnar C8–T1
hypothenar atrophy
Winged scapula (serratus anterior
Long thoracic C5–C7
paralysis)
Diaphragm paralysis (C3,4,5 keeps
Phrenic C3–C5
the diaphragm alive)
■ HIGH-YIELD: Erb's palsy (C5–C6): 'waiter's tip' position. Klumpke's palsy (C8–T1): intrinsic hand
muscles + Horner syndrome.
1.2 Dermatomes Worth Memorising
Level Landmark
C2 Back of head (occiput)
C3 High turtleneck collar area
C4 Low-collar / cape area
C6 Thumb (radial side)
C7 Middle finger
C8 Little finger
T4 Nipple line
USMLE Step 1 Complete Review
2025–2026 Edition
Anatomy · Physiology · Biochemistry · Pharmacology
Subjects Covered
Pathology · Microbiology · Immunology
Total Pages ~50 pages of exam-ready notes
Format Topic summaries · Tables · Mnemonics · High-yield callouts
Best Used For USMLE Step 1 · COMLEX Level 1 · Medical Finals
© 2025 MedNotes Pro | For educational use only | Not a substitute for clinical judgement
, TABLE OF CONTENTS
1. Anatomy & Embryology
3
2. Physiology
8
3. Biochemistry & Genetics
14
4. Pharmacology
20
5. Pathology
27
6. Microbiology & Infectious Disease
34
7. Immunology
40
8. Rapid Review: 100 Must-Know Facts
44
, Chapter 1
Anatomy & Embryology
1.1 Brachial Plexus — Roots, Trunks, Divisions, Cords, Branches
Roots: C5–T1 | Mnemonic: 'Real Texans Drink Cold Beer' (Roots, Trunks, Divisions, Cords,
Branches)
Nerve Root(s) Key Action / Injury Pattern
Deltoid atrophy; loss of shoulder
Axillary C5, C6
abduction (surgical neck # humerus)
Weak elbow flexion & supination;
Musculocutaneous C5–C7
lateral forearm sensory loss
Wrist drop; loss of finger extension
Radial C5–T1 (Saturday night palsy, humeral shaft
#)
Ape hand; carpal tunnel; loss of
Median C6–T1
thenar muscles
Claw hand; intrinsic muscle wasting;
Ulnar C8–T1
hypothenar atrophy
Winged scapula (serratus anterior
Long thoracic C5–C7
paralysis)
Diaphragm paralysis (C3,4,5 keeps
Phrenic C3–C5
the diaphragm alive)
■ HIGH-YIELD: Erb's palsy (C5–C6): 'waiter's tip' position. Klumpke's palsy (C8–T1): intrinsic hand
muscles + Horner syndrome.
1.2 Dermatomes Worth Memorising
Level Landmark
C2 Back of head (occiput)
C3 High turtleneck collar area
C4 Low-collar / cape area
C6 Thumb (radial side)
C7 Middle finger
C8 Little finger
T4 Nipple line
