42.1 Distal Radius, Scaphoid & Common Upper Extremity Fractures

ABFM Family Medicine Certification Study Guide Exam

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1 Chapter 1: Exam Structure, Blueprint & Clinical Decision-Making

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6 Chapter 6: Routine Adult Immunizations

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7 Chapter 7: Pediatric Health Maintenance & Surveillance

7.1 Newborn Examination & Early Postnatal Care 7.2 Well-Child Care, Developmental Surveillance & Milestones 7.3 Pediatric & Adolescent Screening: Vision, Hearing, Anemia & Lead 7.4 Pediatric Oral Health, Dental Screening & Fluoride

8 Chapter 8: Behavioral Health & Safety Screening

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9 Chapter 9: Adult Preventive Screening: Cardiovascular & Metabolic

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10 Chapter 10: Adult Cancer Screening: Breast & Gynecologic

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11 Chapter 11: Adult Cancer Screening: Colorectal, Lung & Prostate

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12 Chapter 12: Sexual Health, Infectious Disease Screening & Contraception

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13 Chapter 13: Reproductive Life Planning, Lactation & Preoperative Care

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14 Chapter 14: Emergent Cardiovascular Conditions

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15 Chapter 15: Cardiac Arrhythmias, Heart Failure & Hypertensive Crises

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16 Chapter 16: Vascular & Thromboembolic Emergencies

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17 Chapter 17: Neurologic Emergencies: Stroke & Altered Consciousness

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18 Chapter 18: Neurologic Trauma & Acute Cranial Emergencies

18.1 Concussion, Moderate-to-Severe TBI & Intracranial Injury 18.2 Thunderclap & Acute Severe Secondary Headaches 18.3 Acute Ophthalmologic Emergencies

19 Chapter 19: Acute Abdominal, Pelvic & Gastrointestinal Emergencies

19.1 Acute Abdominal & Pelvic Pain Triage 19.2 Upper & Lower Gastrointestinal Bleeding 19.3 Acute Hepatic Failure, Cholangitis & Severe Jaundice

20 Chapter 20: Acute Pulmonary & Airway Emergencies

20.1 Acute Hypoxic Respiratory Failure & ARDS 20.2 Severe Community-Acquired Pneumonia & Empyema 20.3 Acute Severe Epistaxis & Airway Obstruction

21 Chapter 21: Acute Traumatic Injuries & Wound Care

21.1 Major Trauma Resuscitation & Initial Assessment 21.2 Burn Assessment, Inhalation Injury & Resuscitation 21.3 Laceration Management, Complex Wounds & Animal Bites

22 Chapter 22: Acute Orthopedic & Musculoskeletal Emergencies

22.1 Acute Ambulatory Fractures & Initial Splinting 22.2 Compartment Syndrome & Major Orthopedic Trauma 22.3 Septic Arthritis & Acute Microcrystalline Crises

23 Chapter 23: Severe Infections, Sepsis & Systemic Emergencies

23.1 Sepsis, Septic Shock & Initial Fluid Resuscitation 23.2 Necrotizing Soft Tissue Infections & Severe CNS Infections 23.3 Anaphylaxis Diagnosis, Epinephrine Dosing & Airway Protection

24 Chapter 24: Metabolic, Endocrine & Electrolyte Emergencies

24.1 Diabetic Ketoacidosis & Hyperosmolar Hyperglycemic State 24.2 Critical Electrolyte Emergencies: Dyskalemias & Dysnatremias 24.3 Severe Calcium Abnormalities & Acute Adrenal Crisis

25 Chapter 25: Hematologic, Urologic & Dental Emergencies

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26 Chapter 26: Psychiatric, Behavioral & Obstetric/Gynecologic Emergencies

26.1 Suicidal Ideation, Acute Agitation & Behavioral Emergencies 26.2 Acute Physical & Sexual Assault Care 26.3 Life-Threatening Vaginal Bleeding & Ectopic Pregnancy 26.4 Environmental Heat Stroke & Severe Hypothermia

27 Chapter 27: Acute Head, Neck & Neurologic Symptoms

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28 Chapter 28: Acute Cranial Nerves, Hearing & Sensory Symptoms

28.1 Peripheral Neuropathies: Bell's Palsy, Carpal Tunnel & Radiculopathy 28.2 Acute Tinnitus, Sudden Sensorineural Hearing Loss & Cerumen Impaction 28.3 Acute Dizziness, Benign Paroxysmal Positional Vertigo & Vestibular Neuritis

29 Chapter 29: Acute Upper Respiratory Tract Infections

29.1 Acute Viral Rhinosinusitis vs. Bacterial Rhinosinusitis 29.2 Acute Pharyngitis: Group A Streptococcus & Centor Criteria 29.3 Acute Otitis Media, Otitis Externa & Serous Effusion

30 Chapter 30: Acute Lower Respiratory Infections & Cough

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31 Chapter 31: Allergic, Nasal & Non-Infectious Pulmonary Conditions

31.1 Allergic Rhinitis & Acute Non-Anaphylactic Allergic Reactions 31.2 Acute Dyspnea in Ambulatory Care 31.3 Interstitial Lung Diseases & Sarcoidosis Presentation

32 Chapter 32: Acute Chest, Cardiac & Vascular Symptoms

32.1 Palpitations Evaluation & Arrhythmia Triage in Primary Care 32.2 Deep Vein Thrombosis & Superficial Thrombophlebitis 32.3 Ambulatory Hypotension & Orthostasis Evaluation

33 Chapter 33: Acute Upper Gastrointestinal Conditions

33.1 Peptic Ulcer Disease & Gastritis 33.2 Dysphagia, Esophagitis & Acute Esophageal Disorders 33.3 Acute Nausea, Vomiting & Foodborne Illness

34 Chapter 34: Acute Lower Gastrointestinal Conditions

34.1 Acute Infectious Diarrhea & Gastroenteritis 34.2 Acute Constipation & Functional Bowel Changes 34.3 Ano-Rectal Disorders: Hemorrhoids, Fissures, Abscesses & Pruritus Ani

35 Chapter 35: Inflammatory, Functional & Malabsorptive GI Disorders

35.1 Acute Flares of Inflammatory Bowel Disease 35.2 Irritable Bowel Syndrome: Diagnosis, Subtyping & Management 35.3 Celiac Disease & Malabsorption Syndromes

36 Chapter 36: Acute Abdominal, Hepatic & Biliary Disorders

36.1 Ambulatory Abdominal & Pelvic Pain Triage 36.2 Acute Cholecystitis, Biliary Colic & Pancreatitis 36.3 Acute Liver Injury & Viral Hepatitis

37 Chapter 37: Acute Abdominal Wall, Hernias & Dental Conditions

37.1 Abdominal Wall, Inguinal & Ventral Hernias 37.2 Acute Dental Pain, Odontogenic Abscess & Aphthous Ulcers 37.3 Acute Edema: Unilateral vs. Bilateral Diagnostic Evaluation

38 Chapter 38: Acute Infectious Dermatoses

38.1 Bacterial Skin Infections: Impetigo, Cellulitis & Cutaneous Abscesses 38.2 Fungal Skin Infections: Tinea Corporis, Cruris, Pedis & Onychomycosis 38.3 Viral Cutaneous Infections: Herpes Simplex, Zoster & Molluscum Contagiosum

39 Chapter 39: Inflammatory, Allergic & Autoimmune Dermatoses

39.1 Atopic Dermatitis, Contact Dermatitis & Eczematous Flares 39.2 Non-Infectious Rashes: Urticaria, Drug Eruptions & Erythema Multiforme 39.3 Cutaneous Malignancies & Premalignant Lesions: AK, BCC, SCC & Melanoma

40 Chapter 40: Acute Shoulder, Elbow & Upper Extremity Injuries

40.1 Rotator Cuff Pathology, Tendinopathy & Shoulder Impingement 40.2 Lateral & Medial Epicondylitis, Olecranon Bursitis & Elbow Sprains 40.3 Wrist & Hand Soft-Tissue Injuries: De Quervain, TFCC & Finger Sprains

41 Chapter 41: Acute Knee, Ankle & Lower Extremity Injuries

41.1 Meniscal Tears, Ligamentous Knee Injuries & Patellofemoral Pain 41.2 Ankle Sprains, Ottawa Ankle Rules & Achilles Tendinopathy 41.3 Plantar Fasciitis, Shin Splints & Overuse Syndromes

42 Chapter 42: Acute Ambulatory Fractures & Dislocations

42.1 Distal Radius, Scaphoid & Common Upper Extremity Fractures 42.2 Metatarsal, Clavicle & Common Lower Extremity Fractures 42.3 Joint Dislocation Management: Nursemaid's Elbow & Shoulder Subluxation

43 Chapter 43: Acute Axial Musculoskeletal Pain & Falls

43.1 Acute Low Back Pain: Red Flags, Strain & Disc Herniation 43.2 Acute Cervical Strain, Whiplash & Axial Neck Pain 43.3 Evaluation of Falls in Ambulatory & Older Patients

44 Chapter 44: Acute Inflammatory Arthropathies & Generalized Pain

44.1 Acute Inflammatory Arthritis & Spondyloarthropathies 44.2 Myalgias, Rhabdomyolysis & Post-Viral Pain Syndromes 44.3 Acute Non-Headache Pain Management Strategies

45 Chapter 45: Acute Renal, Urinary & Genitourinary Conditions

45.1 Uncomplicated UTI, Pyelonephritis & Acute Urethritis 45.2 Hematuria Workup & Glomerulonephritis 45.3 Nephrolithiasis & Acute Urinary Tract Obstruction

46 Chapter 46: Acute Male Genitourinary & Prostatic Conditions

46.1 Acute Prostatitis, Epididymitis & Orchitis 46.2 Acute Scrotal Pain: Torsion vs Appendage, BPH & Male Genital Emergencies 46.3 Acute Urinary Retention & Incontinence Evaluation

47 Chapter 47: Acute Women's Health & Early Pregnancy Care

47.1 Early Pregnancy Diagnosis, Dating & Initial Complications 47.2 Abnormal Uterine Bleeding & Acute Menstrual Disorders 47.3 Premenstrual Syndrome & Premenstrual Dysphoric Disorder

48 Chapter 48: Breast Disorders, STIs & Pediatric Elimination

48.1 Palpable Breast Mass, Mastitis & Nipple Discharge 48.2 Sexually Transmitted Infections: Diagnosis, Staging & CDC Guidelines 48.3 Pediatric Enuresis & Encopresis

49 Chapter 49: Systemic Signs, Metabolic Dysregulation & Miscellaneous Infections

49.1 Acute Fever, Sepsis Screening & FUO in Primary Care 49.2 Acute Hyperglycemia & Symptomatic Hypoglycemia 49.3 Electrolyte Abnormalities: Mild-to-Moderate Disturbances 49.4 Vector-Borne, Tick-Borne & Rickettsial Illnesses

50 Chapter 50: Chronic Cardiovascular Diseases: Hypertension & Ischemia

50.1 Essential Hypertension Management: 2025 AHA/ACC Guideline & JNC Strategies 50.2 Chronic Coronary Artery Disease & Post-MI Secondary Prevention 50.3 Chronic Heart Failure: HFrEF, HFpEF & Quadruple GDMT

51 Chapter 51: Chronic Vascular, Valvular & Dyslipidemic Diseases

51.1 Peripheral Arterial Disease & Claudication 51.2 Chronic Valvular Heart Disease & Murmur Evaluation 51.3 Lipid Disorders & ASCVD Risk-Based Statin Therapy

52 Chapter 52: Chronic Respiratory Diseases: Asthma & COPD

52.1 Chronic Asthma Management: GINA Stepwise SMART Therapy 52.2 Chronic Obstructive Pulmonary Disease: GOLD Recommendations 52.3 Solitary Pulmonary Nodule Evaluation & Fleischner Society Criteria

53 Chapter 53: Chronic Metabolic Diseases: Diabetes Mellitus

53.1 Type 2 Diabetes Management: ADA Pharmacotherapy Algorithms 53.2 Type 1 Diabetes: Basal-Bolus Insulin, CGMs & Diabetic Complications 53.3 Diabetic Microvascular & Macrovascular Disease Surveillance

54 Chapter 54: Obesity, Nutrition & Metabolic Bone Diseases

54.1 Medical & Behavioral Management of Obesity & Incretin Mimetics 54.2 Osteoporosis & Metabolic Bone Disease: DEXA, FRAX & Antiresorptives 54.3 Nutritional Deficiencies: Vitamin D, B12, Iron & Malnutrition

55 Chapter 55: Chronic Endocrine Disorders

55.1 Primary & Subclinical Hypothyroidism, Hyperthyroidism & Nodules 55.2 Adrenal Disorders: Addison's Disease & Cushing's Syndrome 55.3 Hypercalcemia, Hyperparathyroidism & Pituitary Disorders

56 Chapter 56: Chronic Kidney Disease & Venous Disorders

56.1 Chronic Kidney Disease: KDIGO Staging & Renoprotective Therapy 56.2 Chronic Venous Insufficiency, Stasis Dermatitis & Lymphedema 56.3 Chronic Electrolyte & Acid-Base Management in CKD

57 Chapter 57: Chronic Gastrointestinal & Hepatic Diseases

57.1 Gastroesophageal Reflux Disease, Barrett's Esophagus & Dyspepsia 57.2 Chronic Liver Disease: MASLD/NAFLD, Cirrhosis & Portal Hypertension 57.3 Viral Hepatitis B & C: Long-Term Monitoring & DAA Therapy

58 Chapter 58: Colorectal Surveillance & Chronic Pancreaticobiliary Care

58.1 Post-Polypectomy Colorectal Polyp Surveillance Guidelines 58.2 Chronic Pancreatitis & Exocrine Pancreatic Insufficiency 58.3 Chronic Nausea, Gastroparesis & Functional GI Disorders

59 Chapter 59: Chronic Musculoskeletal & Rheumatologic Disorders

59.1 Osteoarthritis: Hip, Knee & Hand Management 59.2 Spinal Conditions: Spinal Stenosis, Spondylolisthesis & Compression Fractures 59.3 Chronic Myopathies & Fibromyalgia Syndrome

60 Chapter 60: Chronic Neurologic & Neurodegenerative Disorders

60.1 Dementia: Alzheimer's, Vascular & Lewy Body Disease 60.2 Parkinson's Disease & Essential Tremor 60.3 Epilepsy: Chronic Antiseizure Medications & Post-Stroke Care

61 Chapter 61: Chronic Peripheral Nerves, Pain & Sensory Disorders

61.1 Diabetic & Chronic Peripheral Neuropathies 61.2 Chronic Pain Syndromes & Chronic Daily Headaches 61.3 Chronic Tinnitus, Presbycusis & Persistent Dizziness

62 Chapter 62: Chronic Psychiatric Disorders

62.1 Major Depressive Disorder & Generalized Anxiety Disorder 62.2 Bipolar Disorder: Maintenance Pharmacotherapy & Lithium Monitoring 62.3 Adult & Pediatric Attention-Deficit/Hyperactivity Disorder

63 Chapter 63: Chronic Behavioral Health & Neurodevelopmental Conditions

63.1 Chronic Behavioral Conditions: PTSD, OCD & Somatization 63.2 Autism Spectrum Disorder & Intellectual Disabilities 63.3 Eating Disorders: Anorexia Nervosa, Bulimia & Binge Eating

64 Chapter 64: Chronic Substance Use Disorders & Tobacco Cessation

64.1 Alcohol Use Disorder: Pharmacotherapy & Relapse Prevention 64.2 Opioid & Stimulant Use Disorders: MOUD & Harm Reduction 64.3 Longitudinal Tobacco Cessation Pharmacotherapy

65 Chapter 65: Chronic Dermatologic Conditions

65.1 Acne Vulgaris, Rosacea & Seborrheic Dermatitis 65.2 Chronic Plaque Psoriasis & Biologic Therapies 65.3 Chronic Eczema, Hidradenitis Suppurativa & Cutaneous Lupus

66 Chapter 66: Chronic Reproductive, Infectious & Geriatric Special Care

66.1 Chronic Menstrual Disorders, Infertility & Sexual Dysfunction 66.2 Menopause Management & Hormone Replacement Therapy 66.3 Chronic HIV Infection Management & Primary Care Integration 66.4 Gender-Affirming Primary Care & Hormone Therapy 66.5 Advance Care Planning, Palliative Care & End-of-Life Symptom Control

67 Chapter 67: Continuity Care: Sleep, Fatigue, Cancer, Pregnancy & the Adult Preventive Visit

67.1 Chronic Insomnia & Obstructive Sleep Apnea 67.2 Chronic Malaise, Fatigue & ME/CFS 67.3 Primary Care During Cancer Treatment & Survivorship 67.4 Routine Prenatal Care & Longitudinal Pregnancy Management 67.5 The Periodic Adult Health Examination & Medicare Annual Wellness Visit

42.1 Distal Radius, Scaphoid & Common Upper Extremity Fractures

Key Takeaways Explain This Topic AI

Colles fracture is an extra-articular distal radius fracture characterized by dorsal displacement and dorsal angulation ('dinner fork deformity') following a fall on an outstretched hand (FOOSH), whereas Smith fracture ('reverse Colles') results from a fall onto a flexed wrist producing volar displacement and volar angulation.

Acceptable closed reduction parameters for distal radius fractures include radial inclination >=15° (normal 21°-25°), volar tilt >0° (neutral to normal 11° volar; dorsal tilt <10°), radial height shortening <3 mm (normal 11-12 mm), and intra-articular step-off <2 mm; failure to meet these thresholds mandates orthopedic surgical referral for open reduction and internal fixation.

Acute median nerve compression resulting in acute carpal tunnel syndrome is the most urgent neurovascular complication of distal radius fractures; sensory testing at the palmar tip of the index finger and motor testing of the abductor pollicis brevis must be documented before and immediately after any closed reduction maneuver.

Scaphoid fractures represent 70% to 80% of all carpal fractures and possess a tenuous retrograde arterial blood supply entering distally from radial artery branches; proximal pole fractures carry high rates of avascular necrosis (AVN) and nonunion. Any patient with anatomical snuffbox or scaphoid tubercle tenderness and normal plain radiographs must be immobilized in a thumb spica splint with repeat imaging in 10 to 14 days or early wrist MRI.

Boxer's fractures (metacarpal neck, classically 5th digit) tolerate up to 30° to 40° of volar angulation due to mobile carpometacarpal articulation and are immobilized in an ulnar gutter splint with metacarpophalangeal joints flexed to 70° to 90° ('intrinsic plus' position); any overlying knuckle laceration ('fight bite') is presumed infected with Eikenella corrodens, requires oral amoxicillin-clavulanate, and must never be closed primarily.

Last updated: September 2026

Fall on Outstretched Hand (FOOSH) Injury Spectrum & Biomechanics

The fall on an outstretched hand (FOOSH) represents the single most common traumatic mechanism of upper extremity injury presenting to ambulatory primary care and urgent care settings. Biomechanically, impact forces are transmitted through the hand and carpus into the forearm bones, elbow, and shoulder girdle. The exact anatomical injury pattern depends on the patient's age, bone mineral density, vector of applied force, and degree of wrist extension at impact:

Wrist Hyperextension (>90°) & Pronation : Transmits peak compressive forces directly to the metaphysis of the distal radius and carpal scaphoid waist. In older osteoporotic adults (>50 years, particularly postmenopausal females), low-energy falls from standing height characteristically produce extra-articular or intra-articular distal radius fractures (Colles fractures). In young athletic adults (15 to 40 years), the dense subchondral bone of the radius resists fracture, shifting mechanical failure to the carpal scaphoid.

Wrist Flexion : A direct fall onto the dorsum of a flexed wrist or a direct blow to the dorsal carpus drives the distal radius fragment volarly, creating a Smith fracture ("reverse Colles").

Forearm Rotation & High Energy : High-velocity impacts with axial load and rotational shear generate intra-articular fracture-dislocations (Barton fractures) or radial styloid avulsions (Chauffeur / Hutchinson fractures). FOOSH INJURY SPECTRUM

• ┌─────────────────── FOOSH ───────────────────┐
• │ │
• ▼ ▼
• [Wrist Extended] [Wrist Flexed]
• │ │
• ┌──────┴──────┐ ▼
• ▼ ▼ [Smith Fracture]
• [Older / Osteo] [Young / High Energy] • Volar displacement
• Colles Frx • Scaphoid Fracture • Volar angulation
• Dorsal tilt • Waist / Proximal pole • "Garden spade"
• "Dinner fork" • AVN / Nonunion risk
• Distal Radius Fractures: Colles vs. Smith vs. Barton

Distal radius fractures represent approximately 17% of all fractures evaluated in adult emergency and family medicine clinics. Accurate radiographic and clinical differentiation dictates immobilization strategies and operative referral.

1. Colles Fracture

Definition : An extra-articular fracture of the distal radius metaphysis located within 2 to 3 cm of the radiocarpal articular surface, featuring dorsal displacement , dorsal angulation (loss of normal volar tilt), and radial shortening.

Classic Deformity : "Dinner fork deformity"—the prominent dorsal displacement of the distal radial fragment and carpus produces an abrupt dorsal step-off resembling an upside-down fork.

Associated Injuries : Ulnar styloid avulsion fractures occur in 50% to 60% of cases, reflecting tearing or strain of the triangular fibrocartilage complex (TFCC). Extensive comminution of the dorsal cortex is common in osteoporotic bone.

2. Smith Fracture ("Reverse Colles")

Definition : A fracture of the distal radius metaphysis featuring volar displacement and volar angulation of the distal fragment.

Classic Deformity : "Garden spade deformity"—the distal fragment and carpus are displaced anteriorly (volarly), creating a prominent step-off on the palmar aspect of the wrist.

Clinical Significance : Smith fractures are inherently far more unstable than Colles fractures. The deforming pull of the flexor tendons causes high rates of secondary displacement following closed reduction. In addition, the volarly displaced bone fragments directly encroach upon the carpal tunnel, placing the median nerve under severe acute compressive strain.

3. Barton Fracture

Definition : A fracture-dislocation of the radiocarpal joint with intra-articular involvement and subluxation of the carpus along with the fractured radial articular rim. Barton fractures can be dorsal (dorsal rim avulsion with dorsal carpal subluxation) or volar (volar rim avulsion with volar carpal subluxation; much more common and unstable).

Management : Barton fractures represent high-energy, highly unstable intra-articular injuries that cannot be successfully maintained with cast immobilization; they uniformly require open reduction and internal fixation (ORIF) with a buttress plate.

Acute Carpal Tunnel Syndrome & Median Nerve Evaluation

Acute median nerve compression—manifesting as acute carpal tunnel syndrome (ACTS)—is the most critical, limb-threatening soft-tissue complication associated with acute distal radius fractures. ACTS results from acute mechanical impingement by volarly displaced bony fragments, elevated interstitial pressure from fracture hematoma, post-injury soft-tissue edema, or iatrogenic excessive wrist flexion during splint application.

• Warning
• RED FLAG: ACUTE CARPAL TUNNEL SYNDROME

Presentation : Progressive, intractable burning pain out of proportion to exam, accompanied by progressive paresthesias, numbness, or tingling in the median nerve sensory distribution.

Mandatory Physical Examination :

Sensory Assessment : Light touch and two-point discrimination over the palmar aspect of the index finger (the most isolated median nerve sensory territory), thumb, long finger, and radial half of the ring finger.

Motor Assessment : Test the Abductor Pollicis Brevis (APB) by instructing the patient to raise the thumb perpendicular to the palm ("point thumb to ceiling") against downward resistance. (Note: Thenar motor loss is a late, severe finding).

Immediate Action : Acute carpal tunnel syndrome is an orthopedic emergency! If the wrist is immobilized in flexion, immediately release all splinting/bandages and place the wrist in neutral. If symptoms fail to resolve rapidly, emergent surgical decompression (carpal tunnel release) and fracture stabilization are required to prevent permanent ischemic axonal death and irreversible thenar atrophy. MEDIAN NERVE CLINICAL EVALUATION

• Domain Testing Maneuver Normal Finding
• ─────────────────────────────────────────────────────────────────────────
• Sensory Two-point discrimination & light Intact sensation (<5-6 mm)
• touch at palmar tip of INDEX over volar thumb, index,
• finger and thumb long, radial ring finger

• Motor (APB) Palmar abduction of thumb Full strength against
• (thumb elevated perpendicular resistance; strong thenar
• to palm toward ceiling) muscle contraction

• Vascular Radial & ulnar artery pulses; Capillary refill <2 seconds;
• palmar capillary refill symmetric bounding pulses
• ─────────────────────────────────────────────────────────────────────────
• Radiographic Assessment & Acceptable Closed Reduction Criteria

Initial diagnostic evaluation of suspected distal radius fractures requires a standard 3-view wrist radiographic series: Posteroanterior (PA), true Lateral, and Oblique views. Precise quantitative measurements must be made to assess fracture stability and determine whether closed reduction is appropriate or surgical intervention is indicated.

Quantitative Radiographic Parameters

Radial Inclination (PA View) :

Measurement : The angle formed between a line perpendicular to the long axis of the radial shaft and a line drawn from the tip of the radial styloid to the ulnar corner of the lunate fossa.

Normal : 21° to 25° .

Acceptable Closed Reduction : >=15° .

Radial Height / Length (PA View) :

Measurement : The vertical distance between two parallel lines drawn perpendicular to the radial shaft: one at the tip of the radial styloid and one at the articular surface of the ulnar head.

Normal : 11 to 12 mm .

Acceptable Closed Reduction : Shortening <3 mm compared to the contralateral uninjured wrist (or absolute height >=8-10 mm).

Volar (Palmar) Tilt (True Lateral View) :

Measurement : The angle between a line perpendicular to the long axis of the radial shaft and a line drawn between the dorsal and volar articular lips of the distal radius.

Normal : 11° volar tilt (normal articular surface slopes palmarward).

Acceptable Closed Reduction : Volar tilt >0° (neutral to normal volar tilt; dorsal tilt <10° is tolerated only in low-demand, elderly osteoporotic patients; young active individuals require neutral or positive volar tilt).

Intra-Articular Step-off & Gap (PA and Lateral Views) :

Measurement : Incongruity of the radiocarpal articular surface (scaphoid and lunate fossae).

Normal : 0 mm (completely anatomical and smooth).

Acceptable Closed Reduction : <2 mm (<1 mm in young, high-demand individuals). Any step-off >=2 mm dramatically increases contact stresses and accelerates post-traumatic radiocarpal osteoarthritis.

Summary of Radiographic Reduction Thresholds

• Radiographic Parameter Normal Anatomical Value Acceptable Closed Reduction Threshold Surgical ORIF Indication
• Radial Inclination 21° to 25° >=15° <15° after reduction
• Radial Height (Shortening) 11 to 12 mm Shortening <3 mm Shortening >=3 mm (relative to ulna)

Volar / Palmar Tilt 11° volar >0° volar (dorsal tilt <10° in elderly) Dorsal tilt >=10° (or dorsal tilt in young)

• Intra-Articular Step-off 0 mm <2 mm (<1 mm in young athletes) Articular step-off >=2 mm
• Ulnar Variance Neutral (0 mm) Neutral to positive variance <2 mm Positive ulnar variance >=3 mm
• Closed Reduction & Splinting Protocols
• Hematoma Block Procedure

Closed reduction in the clinic or urgent care is optimally performed under local hematoma block:

Cleanse the dorsal wrist using sterile chlorhexidine technique.

Palpate the dorsal fracture depression approximately 2 cm proximal to the radiocarpal joint line.

Advance a 20- to 22-gauge, 1.5-inch needle into the dorsal fracture site at a 45° angle.

Aspirate to confirm dark, non-clotting fracture hematoma (confirming intra-fracture location).

Inject 5 to 10 mL of 1% or 2% plain lidocaine (or 0.5% bupivacaine) into the hematoma. Allow 10 to 15 minutes for complete regional periosteal anesthesia.

Reduction Technique

Apply longitudinal traction along the forearm axis, either using finger traps (thumb and index finger) with 10 lbs of counterweight or an assistant providing firm countertraction at the flexed elbow.

Exaggerate the initial deformity slightly (dorsal extension) to disimpact the locked dorsal cortical fragments.

While maintaining continuous longitudinal traction, translate the distal fragment volarly with firm pressure from the examiner's thumbs while simultaneously bringing the wrist into slight flexion (15°-20°) and ulnar deviation.

Avoid the "Cotton-Loder" Position : Extreme wrist flexion combined with extreme ulnar deviation is strictly contraindicated because it dramatically elevates carpal tunnel pressure, compresses the median nerve, and stretches the extensor tendons, leading to acute median neuropathy and complex regional pain syndrome (CRPS).

Splinting Principles: Sugar-Tong Splint

Acute Immobilization Choice : A Sugar-Tong Splint (or volar-dorsal plaster sandwich splint) is the mandatory standard of care in the acute setting.

Application : The sugar-tong splint wraps around the distal elbow from the dorsal MCP joints, around the olecranon, to the volar palmar crease. This restricts forearm pronation and supination (which disrupt distal radioulnar alignment) while leaving the splint open on the radial and ulnar sides.

CRITICAL WARNING ON CASTING : Circumferential casting is strictly contraindicated in acute distal radius fractures ! Acute post-reduction tissue edema peaked over 48 to 72 hours within an unyielding circumferential fiberglass cast produces acute compartment syndrome, ischemic skin necrosis, and severe nerve injury. Convert to a circumferential cast only after 7 to 10 days once swelling has fully resolved.

Repeat post-reduction PA and lateral radiographs and repeat neurovascular checks are mandatory prior to clinic discharge.

Scaphoid (Navicular) Fractures: Anatomy, Blood Supply & AVN Risk

The scaphoid is the most commonly fractured carpal bone, accounting for 70% to 80% of all carpal fractures . It links the proximal and distal carpal rows, acting as a crucial mechanical bridge during wrist flexion, extension, and radial-ulnar deviation. SCAPHOID VASCULAR ARTERIAL SUPPLY

• [Radial Artery] ──► Dorsal Scaphoid Branches
• │
• ▼ (Enters at Distal Pole & Waist)
• ┌─────────────────────────────────┐
• │ DISTAL POLE (10-15% of frx) │ ── Excellent Supply
• │ • Rapid healing (4-6 weeks) │
• ├─────────────────────────────────┤
• │ WAIST (65-70% of frx) │ ── Moderate AVN Risk
• │ • Healing: 10-12 weeks │ (10-30%)
• ├─────────────────────────────────┤

│ PROXIMAL POLE (15-20% of frx) │ ── RETROGRADE FLOW!

• │ • Zero direct vessels │ AVN Risk 50-100%
• │ • Nonunion rate: 30-50% │
• └─────────────────────────────────┘
• Retrograde Vascular Supply & Fracture Location Prognosis

Arterial Anatomy : The scaphoid receives its arterial blood supply predominantly (70% to 80%) from the dorsal scaphoid branches of the radial artery , which penetrate the scaphoid ridge at the waist and distal pole. Intraosseous microvessels then course retrogradely from distal to proximal to supply the proximal pole. The remaining 20% to 30% enters via the volar branches at the distal tubercle.

Vascular Vulnerability : Because no direct arterial branches enter the proximal pole, any transverse fracture traversing the waist or proximal pole severs the intraosseous nutrient vessels feeding the proximal segment:

Distal Pole Fractures (10% to 15%) : Excellent blood supply; rapid union in 4 to 6 weeks; low risk of complications.

Waist Fractures (65% to 70%) : Moderate risk of avascular necrosis (10% to 30%) and delayed union/nonunion (5% to 15%); requires 10 to 12 weeks of immobilization.

Proximal Pole Fractures (15% to 20%) : Highest risk of avascular necrosis (50% to 100%) and nonunion (30% to 50%). Fractures of the proximal pole require prolonged casting (12 to 24 weeks) and frequently warrant early orthopedic surgical referral for percutaneous headless compression screw fixation (Herbert screw).

Long-term Complication : Untreated nonunion progresses inevitably to Scaphoid Nonunion Advanced Collapse (SNAC) —a predictable pattern of wrist arthritis starting at the radioscaphoid joint and advancing across the midcarpal joints, producing chronic wrist pain and permanent functional impairment.

Clinical Examination: The Scaphoid Diagnostic Triad

Three physical examination maneuvers should be routinely performed in every patient presenting with wrist pain following a FOOSH:

Anatomical Snuffbox Tenderness :

Anatomy : Bounded medially (ulnar border) by the tendon of the Extensor Pollicis Longus (EPL) and laterally (radial border) by the tendons of the Abductor Pollicis Longus (APL) and Extensor Pollicis Brevis (EPB) .

Maneuver : Palpate the floor of the snuffbox with the wrist in slight ulnar deviation.

Sensitivity : Exceptionally high ( 90% to 95% ), but specificity is only moderate (approx. 40% to 50%); tenderness rules out fracture when absent, but false positives occur from superficial radial nerve irritation or radial collateral ligament sprains.

Scaphoid Tubercle Tenderness :

Maneuver : Palpate the volar-radial wrist over the bony prominence at the base of the thenar eminence just proximal to the flexor carpi radialis tendon.

Significance : High specificity (approx. 85%) for scaphoid injury.

Pain with Axial Compression of the Thumb :

Maneuver : Grasp the patient's thumb and apply direct longitudinal compressive force through the first metacarpal shaft into the trapezium and scaphoid ("telescoping the thumb").

Significance : Elicits sharp pain directly over the scaphoid.

Radiographic Protocol & The Occult Scaphoid Fracture Protocol

Dedicated 4-View Scaphoid Series : Standard wrist radiographs are inadequate. A complete scaphoid evaluation requires:

• Posteroanterior (PA) view;
• True Lateral view;
• 45° Semi-pronated Oblique view;

Dedicated Scaphoid View : PA view taken with the wrist in 30° of extension and 20° of ulnar deviation . Ulnar deviation straightens the long axis of the scaphoid parallel to the cassette, preventing foreshortening and exposing subtle waist fracture lines.

• Important
• CLINICAL PEARL: THE SUSPECTED OCCULT SCAPHOID FRACTURE

Diagnostic Reality : Up to 10% to 20% of acute scaphoid fractures are radiographically invisible on initial plain radiographs taken on the day of injury due to non-displaced trabecular microfractures.

Mandatory Protocol : In any patient with a suggestive mechanism of injury (FOOSH) and localized tenderness in the anatomical snuffbox, scaphoid tubercle, or with axial thumb compression whose initial 4-view radiographs are completely negative:

Do NOT diagnose a simple wrist sprain!

Immobilize immediately in a short-arm Thumb Spica splint (or cast) with the thumb immobilized to the interphalangeal joint.

Schedule repeat 4-view scaphoid radiographs in 10 to 14 days . Over this interval, osteoclastic bone resorption at the fracture margins widens the fracture gap, making occult fractures easily visible on plain films.

Alternative Modern Pathway : Obtain an early non-contrast MRI of the wrist within 24 to 72 hours of injury. MRI boasts 100% sensitivity and specificity, identifies scaphoid trabecular bone marrow edema immediately, and prevents unnecessary immobilization in patients with simple ligamentous sprains.

Boxer's Fracture (Metacarpal Neck)

A Boxer's fracture is a fracture of the neck of the 5th metacarpal (and occasionally 4th metacarpal), typically resulting from direct axial impact sustained when a clenched fist strikes a hard, unyielding surface (e.g., a wall, door, or another person's jaw). BOXER'S FRACTURE BIOMECHANICS

• Interossei / Lumbricals
• (Pull Volarly)
• │
• ▼
• Metacarpal Shaft ─────► / ◄───── Metacarpal Head
• / (Volarly Angulated)
• /
• [5th Metacarpal: Accepts up to 30°-40°]
• [2nd/3rd Metacarpal: Accepts <10°-15°]
• Biomechanics & Angulation Tolerances

During fracture, the metacarpal head displaces volarly due to the downward vector of the intrinsic interosseous and lumbrical muscles. The degree of acceptable residual volar angulation is directly determined by the mobility of the corresponding carpometacarpal (CMC) joint:

2nd and 3rd Metacarpals : The 2nd and 3rd CMC joints are rigid, stable mortise joints with virtually 0° of motion. As a result, compensatory adaptation is impossible; acceptable volar angulation is <10° to 15° . Any greater angulation causes functional clawing and painful palmar grip prominence.

4th Metacarpal : Possesses approximately 10° to 15° of sagittal CMC motion; accepts up to 20° to 30° of volar angulation .

5th Metacarpal : The 5th CMC joint possesses remarkable compensatory mobility, with 25° to 30° of anteroposterior motion . Because the mobile 5th ray can adapt during grip, the 5th metacarpal neck tolerates up to 30° to 40° of volar angulation (some clinical guidelines accept up to 45°-50° in non-laborers) without causing long-term grip weakness or functional impairment.

ROTATIONAL DEFORMITY IS NEVER ACCEPTABLE : While sagittal plane angulation is well tolerated in the 5th ray, rotational malalignment has ZERO tolerance ! Even 5° of metacarpal rotation results in 1.5 cm of digital overlap ("scissoring") when making a fist. On physical examination, when the patient flexes the fingers, the fingernails must align in the same plane and all digits must point directly toward the scaphoid tubercle.

Splinting Protocol: Ulnar Gutter in "Intrinsic Plus" Position

Splint : Ulnar Gutter Splint covering the 4th and 5th digits and ulnar forearm.

The "Intrinsic Plus" (Edinburgh) Position :

Wrist: 20° to 30° extension.

Metacarpophalangeal (MCP) joints: Flexed to 70° to 90° .

Interphalangeal (PIP and DIP) joints: Extended (0° to 10° flexion).

Biomechanical Rationale : At 70° to 90° of flexion, the MCP collateral ligaments are stretched to their maximal anatomical length (cam effect of metacarpal head). Immobilizing MCPs in extension allows collateral ligaments to slacken, contract, and fibrose, causing permanent joint stiffness and extension contractures!

"Fight Bite" Knuckle Wounds & Eikenella corrodens

A small laceration (even 2 to 3 mm) over the dorsal aspect of the 3rd, 4th, or 5th MCP joint sustained during a fist fight is termed a "fight bite" or clenched-fist injury .

• Caution
• THE CRITICAL FIGHT BITE TRAP

Mechanism : When the punch strikes human teeth, the tooth penetrates the skin, the extensor tendon expansion, and frequently the synovial capsule of the MCP joint. When the hand is subsequently opened and fingers extended, the skin, extensor tendon, and joint capsule shift into different planes, sealing aggressive oral pathogens deep inside the joint space and subaponeurotic compartment.

Microbiology : Classic polymicrobial infection dominated by Eikenella corrodens (a fastidious Gram-negative facultative anaerobe unique to human dental plaque), Streptococcus viridans , Staphylococcus aureus , and oral anaerobes ( Fusobacterium , Peptostreptococcus ).

MANAGEMENT RULES :

NEVER CLOSE A FIGHT BITE PRIMARILY! Suturing a fight bite seals virulent oral anaerobes within an enclosed space, virtually guaranteeing septic tenosynovitis, purulent arthritis, and osteomyelitis.

Perform copious bedside wound irrigation with sterile normal saline (at least 200-500 mL) and careful exploration through a full arc of motion.

First-Line Antibiotic : Oral Amoxicillin-clavulanate 875/125 mg PO BID for 7 to 10 days (covers Eikenella , Staph, Strep, and anaerobes).

PENICILLIN ALLERGY WARNING : Eikenella corrodens is intrinsically RESISTANT to cephalexin, clindamycin, erythromycin, and vancomycin ! If the patient has a severe penicillin allergy, prescribe Moxifloxacin 400 mg PO daily OR Ciprofloxacin 500 mg PO BID PLUS Clindamycin 300 mg PO TID .

Evaluate for Kanavel's Four Cardinal Signs of Flexor Tenosynovitis (symmetric sausage digit swelling, held in slight flexion, tenderness along flexor sheath, severe pain on passive extension). Immediate hand surgery consultation for operative I&D is required if tenosynovitis or septic arthritis is present.

Loading diagram... FOOSH Wrist Injury Evaluation & Triage Algorithm