Upper Limb

🟢 Lite — Quick Review (1h–1d)

Rapid summary for last-minute revision before your exam.

Upper Limb — Key Facts for NEET PG

• Brachial Plexus: Roots (C5-T1) → Trunks → Divisions → Cords → Branches; Terminal branches: musculocutaneous, axillary, radial, median, ulnar nerves
• Axilla: Pyramidal space; Contents: Axillary artery/vein, brachial plexus, lymph nodes, fat
• Carpal Tunnel: Flexor retinaculum + carpal bones; Contents: Median nerve + 9 tendons (flexors); Carpal tunnel syndrome → median nerve compression
• Cubital Fossa: Contents (lateral to medial): Tendon of biceps, brachial artery (bifurcates into radial and ulnar), median nerve
• ⚡ Exam tip: Innervation of hand: Median (thenar eminence + first 2 lumbricals), Ulnar (hypothenar + medial 1.5 + deep branches)

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🟡 Standard — Regular Study (2d–2mo)

Standard content for students with a few days to months.

Upper Limb — NEET PG Study Guide

Shoulder Region

Bones: Clavicle, scapula, humerus

Joints:

• Glenohumeral (ball and socket) — most mobile
• Acromioclavicular
• Sternoclavicular
• Scapulothoracic (not a true joint)

Rotator Cuff (SITS):

• Supraspinatus: Abduction initiation
• Infraspinatus: External rotation
• Teres minor: External rotation
• Subscapularis: Internal rotation

Arm (Brachium)

Compartments:

• Anterior: Biceps brachii, brachialis, coracobrachialis; Musculocutaneous nerve
• Posterior: Triceps brachii; Radial nerve

Forearm (Antebrachium)

Compartments:

• Anterior (flexor): 4 layers of muscles; Median and ulnar nerves
• Posterior (extensor): 4 layers; Radial nerve (deep branch)

Hand

Intrinsic Muscles:

• Thenar: Opponens pollicis, abductor pollicis brevis, flexor pollicis brevis (median nerve)
• Hypothenar: Opponens digiti minimi, abductor digiti minimi, flexor digiti minimi (ulnar nerve)
• Lumbricals (4): Flexion at MCP, extension at IP; First 2 median, last 2 ulnar
• Interossei (4 dorsal + 3 palmar): Abduction/adduction of fingers; Ulnar nerve

NCE Exam Pattern

Common question types:

1. Brachial plexus and terminal nerves
2. Muscles, attachments, and actions
3. Nerve injuries and deficits
4. Vascular anatomy
5. Clinical correlations (carpal tunnel,cubital tunnel)

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🔴 Extended — Deep Study (3mo+)

Comprehensive coverage for students on a longer study timeline.

Upper Limb — Comprehensive NEET PG Notes

Detailed Theory

1. Clavicle and Scapula

Clavicle:

• S-shaped bone connecting scapula to sternum
• Only bony connection between trunk and upper limb
• Functions: Transmits weight, provides attachment, allows arm mobility
• Common fracture site: Junction of middle and outer thirds
• Fracture displacement: Medial fragment elevated by sternocleidomastoid, lateral fragment depressed by arm weight

Scapula:

• Triangular bone with 3 processes: Acromion, coracoid process, spine
• Supraspinatus passes beneath acromion (impingement syndrome)
• Glenoid fossa: Shallow socket for glenohumeral joint
• Scapular notch: Transmitted by suprascapular nerve

2. Shoulder Joint (Glenohumeral)

Articular surfaces:

• Humeral head (1/3 of sphere)
• Glenoid fossa (shallow, deepened by glenoid labrum)

Capsule:

• Lax to allow mobility
• Attachments: Anatomical neck of humerus to glenoid margin
• Reinforced by rotator cuff

Ligaments:

• Glenohumeral ligaments (superior, middle, inferior)
• Coracohumeral ligament
• Transverse humeral ligament

Bursae (reduce friction):

• Subacromial-subdeltoid bursa (most important)
• Subscapular bursa
• Infraspinatus bursa

3. Axilla

Boundaries:

• Apex: Clavicle, coracoid process, 1st rib
• Base: Axillary fascia, skin
• Anterior: Pectoralis major, pectoralis minor, subclavius
• Posterior: Subscapularis, latissimus dorsi, teres major
• Medial: Serratus anterior, chest wall
• Lateral: Coracobrachialis, biceps

Contents:

• Axillary artery (continuation of subclavian)
  • Divided by pectoralis minor into 3 parts: 1st (above), 2nd (behind), 3rd (below)
• Axillary vein (continuation of basilic)
• Brachial plexus
• Axillary lymph nodes (5 groups: lateral, medial, anterior, posterior, central)
• Fat and areolar tissue

Axillary Artery Branches:

1. Superior thoracic (1st part)
2. Thoracoacromial (2nd part)
3. Lateral thoracic (2nd part)
4. Subscapular (3rd part)
5. Anterior circumflex humeral
6. Posterior circumflex humeral

4. Brachial Plexus

Formation (C5-T1):

Roots (5): C5, C6, C7, C8, T1
   ↓
Trunks (3): Upper (C5-6), Middle (C7), Lower (C8-T1)
   ↓
Divisions (6): Anterior and posterior of each trunk
   ↓
Cords (3): Lateral (anterior divisions of upper/middle), Posterior (all posterior), Medial (anterior of lower)
   ↓
Terminal Branches (5):
- Musculocutaneous (lateral cord)
- Axillary (posterior cord)
- Radial (posterior cord)
- Median (medial and lateral cords)
- Ulnar (medial cord)

Important Branches Above Cords:

• Dorsal scapular (C5): Rhomboids, levator scapulae
• Long thoracic (C5,6,7): Serratus anterior (winging of scapula)
• Suprascapular (upper trunk): Supraspinatus, infraspinatus
• Nerve to subclavius (C5,6)
• Pectoral nerves (lateral and medial): Pectoralis major and minor

Important Branches Below Cords:

• Musculocutaneous: Flexion of elbow, sensation lateral forearm
• Axillary: Deltoid (abduction 15-90°), teres minor (lateral rotation), sensation lateral shoulder
• Radial: All extensors of arm and forearm, sensation posterior arm/forearm
• Median: Flexors of forearm (except ulnar half of deep), thenar muscles (except adductor pollicis)
• Ulnar: Intrinsic hand muscles, sensation medial 1.5 fingers

5. Arm (Brachium)

Anterior Compartment:

Biceps Brachii:

• Origin: Short head (coracoid), Long head (supraglenoid tubercle)
• Insertion: Radial tuberosity, bicipital aponeurosis
• Actions: Flexion of elbow, supination of forearm, weak shoulder flexion
• Innervation: Musculocutaneous

Brachialis:

• Origin: Distal anterior humerus
• Insertion: Coronoid process of ulna
• Action: Powerful elbow flexion
• Innervation: Musculocutaneous (main), radial (small portion)

Coracobrachialis:

• Innervation: Musculocutaneous

Posterior Compartment:

Triceps Brachii:

• Long head: Infraglenoid tubercle
• Lateral head: Posterior humerus above radial groove
• Medial head: Posterior humerus below radial groove
• Insertion: Olecranon
• Actions: Extension of elbow (primary), long head stabilizes shoulder
• Innervation: Radial nerve

6. Cubital Fossa

Boundaries:

• Superior: Line connecting medial and lateral epicondyles
• Lateral: Brachioradialis
• Medial: Pronator teres
• Floor: Brachialis, supinator
• Roof: Fascia, skin, superficial veins (cephalic/median cubital/basilic)

Contents (lateral to medial):

1. Biceps tendon
2. Brachial artery (bifurcates at neck of radius)
3. Median nerve

Deep Structure: Radial nerve (between brachioradialis and brachialis)

Clinical: Brachial pulse for BP measurement; Median cubital vein for venipuncture

7. Forearm — Anterior Compartment

Superficial Layer (medial to lateral):

1. Pronator teres: Pronation, elbow flexion; Median nerve
2. Flexor carpi radialis: Flexion and abduction of wrist; Median nerve
3. Palmaris longus: Weak wrist flexion; Median nerve
4. Flexor carpi ulnaris: Flexion and adduction of wrist; Ulnar nerve
5. Flexor digitorum superficialis (FDS): Flexion of PIP joints; Median nerve

Intermediate Layer:

• Flexor digitorum profundis (FDP): Flexion of DIP, supplied by anterior interosseous (median) for lateral 2 fingers and ulnar for medial 2

Deep Layer:

• Flexor pollicis longus: Flexion of thumb IP; Anterior interosseous (median)
• Pronator quadratus: Pronation; Anterior interosseous (median)

8. Hand — Intrinsic Muscles

Thenar Eminence (median nerve):

• Abductor pollicis brevis: Abduction of thumb
• Opponens pollicis: Opposition of thumb
• Flexor pollicis brevis: Flexion of thumb MCP

Hypothenar Eminence (ulnar nerve):

• Abductor digiti minimi: Abduction of little finger
• Flexor digiti minimi: Flexion of little finger MCP
• Opponens digiti minimi: Opposition

Midpalmar Muscles:

• Lumbricals (4): Flex MCP, extend IP; Median nerve (first 2), Ulnar nerve (last 2)
• Dorsal interossei (4): Abduction of fingers; Ulnar nerve
• Palmar interossei (3): Adduction of fingers; Ulnar nerve

9. Nerve Injuries

Axillary Nerve (C5,6):

• Injury: Surgical neck of humerus fracture
• Deficits: Loss of shoulder abduction (deltoid), lateral shoulder anesthesia
• Common test: Abduction against resistance

Radial Nerve (C5-T1):

• Injury: Mid-shaft humerus fracture, Saturday night palsy (compressed in spiral groove)
• Deficits: Wrist drop (can’t extend wrist/fingers), sensory loss posterior arm/forearm
• Spares: Sensation over deltoid, brachioradialis (if high injury)

Median Nerve (C5-T1):

• Injury: Carpal tunnel (compression), supracondylar fracture
• Deficits (wrist): Ape hand (thenar atrophy), median claw (FDP lateral 2 not working), palmar anesthesia
• Carpal tunnel: Tinel’s sign (tapping), Phalen’s test (wrist flexion)

Ulnar Nerve (C8-T1):

• Injury: Medial epicondyle fracture, cubital tunnel
• Deficits: Claw hand (ulnar 2 fingers), ulnar claw (worse with extension), sensory loss medial 1.5 fingers
• Froment’s sign: Compensates for lost adductor pollicis

10. Vascular Anatomy

Axillary Artery (continues as brachial artery at lower border of teres major):

• Branches: See above

Brachial Artery:

• Bifurcates into radial and ulnar arteries at cubital fossa (bifurcation at neck of radius)
• Branches: Profunda brachii (with radial nerve in radial groove)

Radial Artery:

• Pulse site (lateral to flexor carpi radialis at wrist)
• Contributes to superficial palmar arch

Ulnar Artery:

• Larger terminal branch
• Contributes to superficial (via superficial palmar branch) and deep palmar arches

Superficial Palmar Arch (ulnar dominant):

• Completed by superficial branch of radial or other vessels
• Digital arteries to fingers

Deep Palmar Arch (radial dominant):

• Completed by deep branch of ulnar
• Located more proximal

11. Clinical Correlations

Shoulder Impingement:

• Supraspinatus tendon compression under acromion
• Pain with abduction (especially 60-120°)
• Neer impingement sign, Hawkins test

Rotator Cuff Tears:

• Supraspinatus most commonly affected
• Drop arm test: Can’t hold arm abducted at 90°
• MRI for diagnosis

Tennis Elbow (Lateral Epicondylitis):

• Extensor carpi radialis brevis origin
• Pain with wrist extension against resistance

Golfer’s Elbow (Medial Epicondylitis):

• Flexor-pronator origin
• Pain with wrist flexion against resistance

Carpal Tunnel Syndrome:

• Compression of median nerve
• Symptoms: Numbness/tingling in median nerve distribution
• Treatment: Splinting, corticosteroid injection, surgical release

Cubital Tunnel Syndrome:

• Ulnar nerve compression at elbow
• Numbness in ulnar 1.5 fingers, especially with elbow flexion

Practice Questions for NEET PG

1. Describe the formation of the brachial plexus and list its terminal branches.
2. Explain the course and branches of the axillary artery.
3. Discuss the intrinsic muscles of the hand and their innervation.
4. Describe the contents of the cubital fossa.
5. Explain the clinical features and anatomical basis of carpal tunnel syndrome.

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