C5-C6 Fractured surgical neck of humerus, anterior dislocation of humerus. Flattened deltoid, loss of arm abduction (>15°), loss of sensation over deltoid/lateral arm. Musculocutaneous Nerve C5-C7 Upper trunk compression. Loss of forearm flexion/supination (Coracobrachialis), loss of sensation over lateral forearm. Radial Nerve C5-T1 Compression of axilla ("Saturday night palsy"), humerus fracture (midshaft/supracondylar), repetitive pronation/supination (supinator canal injury). Triceps weakness (axillary injury), wrist drop (loss of elbow/wrist/finger extension), loss of sensation over posterior arm/forearm/dorsal hand, ↓ grip strength. Supinator canal injury: "finger drop" without wrist drop/sensory deficits. Median Nerve C5-T1 Supracondylar fracture of humerus (proximal), carpal tunnel syndrome, wrist laceration (distal). Proximal: "Pope's blessing" (loss of flexion of lateral fingers, inability to oppose thumb), loss of wrist flexion, thenar eminence atrophy, loss of sensation over thenar eminence and lateral 3½ fingers. Distal: "Ape hand" (thumb adducted, cannot oppose/abduct), thenar atrophy, sensation spared (palmar cutaneous branch). Recurrent Branch of Median Nerve Superficial laceration near flexor retinaculum. Motor innervation to thenar muscles lost (immobilizes thumb), sensation intact. Ulnar Nerve C8-T1 Fracture of medial epicondyle ("funny bone" - proximal), fractured hook of hamate (distal). Loss of finger abduction/adduction (interossei), "ulnar claw" on digit extension (paralysis of medial lumbricals), radial deviation of wrist upon flexion (proximal lesion), loss of wrist flexion/medial finger flexion, loss of sensation over medial 1½ fingers/hypothenar eminence. Ulnar Paradox: Proximal lesions may have less obvious clawing due to loss of flexor digitorum profundus. Long Thoracic Nerve C5-C7 Axillary lymph node dissection, lateral chest wall injury. Scapular winging (serratus anterior paralysis), weakness in abducting arm above horizontal.

Common Humerus Fractures & Associated Neurovascular Injuries

Surgical neck: Axillary nerve, posterior humeral circumflex artery.
Midshaft: Radial nerve, profunda brachii artery (deep brachial artery).
Supracondylar: Brachial artery, median nerve.
- Anterolateral displacement $\rightarrow$ radial nerve injury.
- Anteromedial displacement $\rightarrow$ median nerve and brachial artery injury.
- Posterior displacement $\rightarrow$ ulnar nerve injury.
Medial epicondyle: Ulnar nerve.

Wrist & Hand Fractures/Conditions

Distal Radius Fractures:
- Smith's fracture: Ventral angulation, distal fragment anteriorly displaced (fall on dorsum of flexed wrist).
- Colles' fracture: Dorsal angulation, distal fragment dorsally displaced ("dinner fork deformity," fall on outstretched hand). Ulnar styloid process avulsion common.
Scaphoid Fracture: Most common carpal bone fracture.
- Cause: Fall on outstretched hand (hyperextended,