Updated: 7/6/2018

Ulnar Neuropathies

Review Topic
2 2
  • The most common ulnar neuropathies are
    • cubital tunnel syndrome 
      • caused by ulnar nerve compression at the elbow
    • ulnar tunnel syndrome
      • caused by ulnar nerve compression at the wrist in Guyon's canal
  • The ulnar nerve is a branch of the medial cord of the brachial plexus
    • ulnar sensory function
      • sensory branches
        • dorsal cutaneous branch
        • palmar cutaneous branch
        • superficial terminal branches
    • ulnar nerve innervates 
      • forearm
        • flexor carpi ulnaris
        • flexor digitorum profundus III and IV
      • thenar
        • adductor pollicis
        • deep head of flexor pollicis brevis (FPB)
      • fingers
        • dorsal and palmar interossei
        • 3rd and 4th lumbrical (1st and 2nd by median nerve)
      • digiti minimi
        • abductor digiti minimi
        • opponens digiti minimi
        • flexor digiti minimi
  • Ulnar nerve at elbow 
    • see medial approach to elbow 
    • pierces intramuscular septum at Arcade of Struthers
    • enters cubital tunnel which is formed by
      • roof formed by Osborne's ligament (travels from the medial epicondyle to the olecranon)
      • floor formed by posterior and transverse bands of MCL
  • Ulnar nerve at wrist
    • nerve enters Guyon's canal which is created by 
      • floor formed by tranverse carpal ligament, pisohamate ligament, pisometacarpal ligament, and opponens digiti minimi
      • roof formed by volar carpal ligament
      • ulnar wall formed by Pisiform and abductor digiti mini
      • radial wall formed by Hook of hamate
  • Symptoms
    • same for both cubital and ulnar tunnel syndrome
    • paresthesias over small finger and ulnar half of 4th finger and ulnar dorsum of the hand 
      • exacerbating activities include cell phone use (excessive flexion)
    • night symptoms
      • caused by sleeping with arm in flexion
  • Physical exam 
    • deformity
      • claw hand deformity 
    • sensory
      • decreased sensation in ulnar 1 1/2 digits
    • motor
      • weakened grasp
      • weak pinch
    • provocative tests for cubital tunnel syndrome
      • Tinnel sign positive over cubital tunnel
  • Radiographs
    • usually normal
  • EMG / NCV
    • helpful to establish the diagnosis
  • Nonoperative
    • NSAIDS, activity modification, and night time bracing
  • Operative
    • ulnar nerve decompression

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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

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(M2.OR.17.4798) A 27-year-old young man presents to his primary care physician for weakness and tingling in his hand. The patient is an avid bodybuilder and has noticed that his grip strength has gradually worsened in both hands with symptoms worse at the end of a long workout. The patient has a past medical history of anabolic steroid use in high school. His current medications include a multivitamin, fish oil, and whey protein supplements. On physical exam, you note a muscular young man with male pattern hair loss. The patient has a loss of sensation bilaterally over the volar surface of the 4th and 5th digits and over the medial aspect of the volar forearm. The patient has 3/5 grip strength of his left hand and 2/5 grip strength of his right hand. There is also notable weakness of finger adduction and abduction. The rest of the patient's physical exam is within normal limits.

Which of the following is the most likely diagnosis?
Review Topic | Tested Concept

QID: 109237

Brachial plexopathy




Cubital tunnel compression




Guyon's canal compression




Carpal tunnel syndrome




Posterior interosseous nerve compression



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