Updated: 11/21/2018

Distortions of the Hand / Claw Hand

Review Topic
  • A 32-year-old woman presents to the emergency room with severe right arm pain after being involved in a motor vehicle collision. She has a comminuted open fracture of the right distal radius and ulna. She is taken to the operating room where lesions to the distal ulnar artery and nerve are noted. She undergoes multiple surgical procedures over the following several months until her radius and ulna appear well healed. However, she has residual hand weakness and is unable to completely open her hand after making a fist. On exam, her 4th and 5th metacarpophalangeal joints are hyperextended while her 4th and 5th interphalangeal joints are flexed. 
  • Lesions to different nerves of the upper extremity will lead to specific hand distortions
    • ulnar claw hand
    • hand of benediction
    • Klumpke total claw hand
  • Relevant anatomy
    • muscles
      • lumbricals
        • innervation
          • 2nd/3rd digit lumbricals innervated by median nerve
          • 4th/5th digit lumbricals innervated by ulnar nerve
        • actions
          • metacarpophalangeal (MCP) joint flexion
          • proximal interphalangeal (PIP) and distal interphalangeal (DIP) joint extension
      • extensor digitorum communis (EDC) 
        • innervation
          • posterior interosseous nerve (branch of the radial nerve)
        • actions
          • finger extension
      • flexor digitorum superficialis (FDS)
        • innervation
          • anterior interosseous nerve
        • actions
          • PIP flexion
      • flexor digitorum profundus (FDP)
        • innervation
          • 2nd/3rd digits innervated by anterior interosseous nerve (branch of the median nerve)
          • 4th/5th digits innervated by ulnar nerve
        • actions
          • DIP flexion
      • dorsal and palmar interossei
        • innervation
          • ulnar nerve
        • actions
          • dorsal interossei abduct the fingers
          • palmar interossei adduct the fingers
      • thenar eminence musculature
        • muscles
          • flexor pollicis brevis
          • abductor pollicis brevis
          • opponens pollicis
        • innervation
          • recurrent branch of median nerve
          • flexor pollicis brevis also receives its innervation from the ulnar nerve
        • actions
          • thumb flexion, abduction, and opposition
Ulnar Claw Hand
  • Physical exam  
    • 4th and 5th MCP joints are extended
    • 4th and 5th PIP and DIP joints are flexed
    • weakness in finger abduction and adduction
    • patient is able to make a fist but is not able to completely open their 4th and 5th digits
  • Pathoanatomy
    • nerve involved
      • distal ulnar nerve (at the wrist)
    • muscles involved
      • weakened 4th and 5th lumbricals
      • weakened dorsal and palmar interossei
Hand of Benediction
  • Physical exam
    • 2nd and 3rd MCP, PIP, and DIP joints are extended
    • weakness in thumb abduction and opposition
    • patient cannot make a fist due to inability to flex 2nd and 3rd digits
  • Pathoanatomy
    • nerve involved
      • median nerve at the forearm or elbow
    • muscles involved
      • weakened 2nd and 3rd lumbricals
      • weakened FDP to 2nd and 3rd digits
      • weakened thenar musculature
Klumpke Total Claw Hand
  • Physical exam
    • MCP joints are hyperextended
    • PIP and DIP joints are flexed
    • wrist is hyperextended
    • weakness in thumb abduction and opposition
    • forearm is supinated
  • Pathoanatomy
    • nerve involved
      • lower trunk of the brachial plexus (C8/T1)
    • muscles involved
      • all intrinsic muscles of the hand
        • lumbricals
        • dorsal and palmar interossei
        • thenar eminence
      • wrist flexors
      • forearm pronators

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Questions (1)
Lab Values
Blood, Plasma, Serum Reference Range
ALT 8-20 U/L
Amylase, serum 25-125 U/L
AST 8-20 U/L
Bilirubin, serum (adult) Total // Direct 0.1-1.0 mg/dL // 0.0-0.3 mg/dL
Calcium, serum (Ca2+) 8.4-10.2 mg/dL
Cholesterol, serum Rec: < 200 mg/dL
Cortisol, serum 0800 h: 5-23 μg/dL //1600 h:
3-15 μg/dL
2000 h: ≤ 50% of 0800 h
Creatine kinase, serum Male: 25-90 U/L
Female: 10-70 U/L
Creatinine, serum 0.6-1.2 mg/dL
Electrolytes, serum  
Sodium (Na+) 136-145 mEq/L
Chloride (Cl-) 95-105 mEq/L
Potassium (K+) 3.5-5.0 mEq/L
Bicarbonate (HCO3-) 22-28 mEq/L
Magnesium (Mg2+) 1.5-2.0 mEq/L
Estriol, total, serum (in pregnancy)  
24-28 wks // 32-36 wks 30-170 ng/mL // 60-280 ng/mL
28-32 wk // 36-40 wks 40-220 ng/mL // 80-350 ng/mL
Ferritin, serum Male: 15-200 ng/mL
Female: 12-150 ng/mL
Follicle-stimulating hormone, serum/plasma Male: 4-25 mIU/mL
Female: premenopause: 4-30 mIU/mL
midcycle peak: 10-90 mIU/mL
postmenopause: 40-250
pH 7.35-7.45
PCO2 33-45 mmHg
PO2 75-105 mmHg
Glucose, serum Fasting: 70-110 mg/dL
2-h postprandial:<120 mg/dL
Growth hormone - arginine stimulation Fasting: <5 ng/mL
Provocative stimuli: > 7ng/mL
Immunoglobulins, serum  
IgA 76-390 mg/dL
IgE 0-380 IU/mL
IgG 650-1500 mg/dL
IgM 40-345 mg/dL
Iron 50-170 μg/dL
Lactate dehydrogenase, serum 45-90 U/L
Luteinizing hormone, serum/plasma Male: 6-23 mIU/mL
Female: follicular phase: 5-30 mIU/mL
midcycle: 75-150 mIU/mL
postmenopause 30-200 mIU/mL
Osmolality, serum 275-295 mOsmol/kd H2O
Parathyroid hormone, serume, N-terminal 230-630 pg/mL
Phosphatase (alkaline), serum (p-NPP at 30° C) 20-70 U/L
Phosphorus (inorganic), serum 3.0-4.5 mg/dL
Prolactin, serum (hPRL) < 20 ng/mL
Proteins, serum  
Total (recumbent) 6.0-7.8 g/dL
Albumin 3.5-5.5 g/dL
Globulin 2.3-3.5 g/dL
Thyroid-stimulating hormone, serum or plasma .5-5.0 μU/mL
Thyroidal iodine (123I) uptake 8%-30% of administered dose/24h
Thyroxine (T4), serum 5-12 μg/dL
Triglycerides, serum 35-160 mg/dL
Triiodothyronine (T3), serum (RIA) 115-190 ng/dL
Triiodothyronine (T3) resin uptake 25%-35%
Urea nitrogen, serum 7-18 mg/dL
Uric acid, serum 3.0-8.2 mg/dL
Hematologic Reference Range
Bleeding time 2-7 minutes
Erythrocyte count Male: 4.3-5.9 million/mm3
Female: 3.5-5.5 million mm3
Erythrocyte sedimentation rate (Westergren) Male: 0-15 mm/h
Female: 0-20 mm/h
Hematocrit Male: 41%-53%
Female: 36%-46%
Hemoglobin A1c ≤ 6 %
Hemoglobin, blood Male: 13.5-17.5 g/dL
Female: 12.0-16.0 g/dL
Hemoglobin, plasma 1-4 mg/dL
Leukocyte count and differential  
Leukocyte count 4,500-11,000/mm3
Segmented neutrophils 54%-62%
Bands 3%-5%
Eosinophils 1%-3%
Basophils 0%-0.75%
Lymphocytes 25%-33%
Monocytes 3%-7%
Mean corpuscular hemoglobin 25.4-34.6 pg/cell
Mean corpuscular hemoglobin concentration 31%-36% Hb/cell
Mean corpuscular volume 80-100 μm3
Partial thromboplastin time (activated) 25-40 seconds
Platelet count 150,000-400,000/mm3
Prothrombin time 11-15 seconds
Reticulocyte count 0.5%-1.5% of red cells
Thrombin time < 2 seconds deviation from control
Plasma Male: 25-43 mL/kg
Female: 28-45 mL/kg
Red cell Male: 20-36 mL/kg
Female: 19-31 mL/kg
Cerebrospinal Fluid Reference Range
Cell count 0-5/mm3
Chloride 118-132 mEq/L
Gamma globulin 3%-12% total proteins
Glucose 40-70 mg/dL
Pressure 70-180 mm H2O
Proteins, total < 40 mg/dL
Sweat Reference Range
Chloride 0-35 mmol/L
Calcium 100-300 mg/24 h
Chloride Varies with intake
Creatinine clearance Male: 97-137 mL/min
Female: 88-128 mL/min
Estriol, total (in pregnancy)  
30 wks 6-18 mg/24 h
35 wks 9-28 mg/24 h
40 wks 13-42 mg/24 h
17-Hydroxycorticosteroids Male: 3.0-10.0 mg/24 h
Female: 2.0-8.0 mg/24 h
17-Ketosteroids, total Male: 8-20 mg/24 h
Female: 6-15 mg/24 h
Osmolality 50-1400 mOsmol/kg H2O
Oxalate 8-40 μg/mL
Potassium Varies with diet
Proteins, total < 150 mg/24 h
Sodium Varies with diet
Uric acid Varies with diet
Body Mass Index (BMI) Adult: 19-25 kg/m2

(M1.MK.8) A 37-year old female presents with "clumsy" hands and clawing of her 4th and 5th finger that has been progressively worsening over the past year. On physical exam, she has decreased pinch strength and paresthesias over her 5th finger. A clinical photograph is shown in Figure A. Which of the following best explains her condition? Review Topic

QID: 101945

Median nerve compression in the carpal tunnel




Median nerve compression in the cubital tunnel




Ulnar nerve compression in Guyon's canal




Ulnar nerve compression by the ligament of Struthers




Radial nerve compression at the arcade of Frohse




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