The Daily Differential — Tuesday, May 12, 2026

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Proximal and Distal Biceps Tendon Rupture

Biceps tendon rupture can be mistaken for a simple strain, but distal ruptures often need early surgical repair to preserve supination and flexion strength.

At the Bedside

Anatomy
Proximal rupture: usually long head of biceps at shoulder; more common, often nonoperative.
Distal rupture: tendon avulses from radial tuberosity; less common, more functionally significant.
History
Sudden eccentric load: lifting heavy object, catching falling object, deadlift, forced elbow extension.
Patient may report a “pop,” acute pain, bruising, weakness.
Risk factors: age, male sex, smoking, anabolic steroid use, fluoroquinolone exposure, chronic tendinopathy.
Exam
Proximal rupture
Anterior shoulder pain.
Ecchymosis upper arm.
“Popeye” deformity: distal bulging of biceps muscle belly.
Usually preserved elbow function.
Distal rupture
Antecubital pain/swelling/ecchymosis.
Weakness with supination > flexion.
Loss of palpable distal biceps tendon.
Hook test: with elbow flexed 90° and supinated, examiner attempts to hook distal biceps tendon laterally. Inability suggests distal rupture.
Biceps squeeze test may show absent supination.
Imaging
X-rays if trauma, concern for avulsion fracture, dislocation, or alternative diagnosis.
Ultrasound can identify tendon discontinuity/retraction if skilled operator available.
MRI is best for defining complete vs partial tear and surgical planning, usually outpatient/orthopedic-directed unless diagnostic uncertainty is high.
ED management
Analgesia, ice, sling for comfort.
Avoid aggressive manipulation.
Document neurovascular exam, especially median/radial/ulnar nerve function and distal perfusion.
Disposition
Proximal rupture: outpatient ortho/sports medicine; often nonoperative unless young athlete, high-demand worker, cosmetic concern, or associated rotator cuff pathology.
Distal rupture: urgent orthopedic referral, ideally within days. Surgical repair is often preferred in active patients and is time-sensitive because tendon retraction/scarring complicates delayed repair.
Immediate consult if open injury, neurovascular compromise, associated fracture/dislocation, or compartment concerns.

A Classic Presentation

A 42-year-old male powerlifter feels a sudden pop in his antecubital fossa while lowering a heavy deadlift. He has swelling and bruising near the elbow and marked weakness with resisted supination. The distal biceps tendon cannot be hooked on exam. X-rays show no fracture. He is placed in a sling, given analgesics, instructed to avoid lifting, and referred urgently to orthopedics for suspected distal biceps tendon rupture.

Study Directive

Practice the hook test technique on a normal elbow.
Compare proximal vs distal rupture findings in a two-column memory card.
Review ultrasound images of normal vs ruptured distal biceps tendon.
Memorize: proximal = usually outpatient/nonoperative; distal = urgent ortho.

Key Medications

Ibuprofen: 400–600 mg PO q6h PRN.
Naproxen: 500 mg PO once, then 250–500 mg PO BID PRN.
Acetaminophen: 650–1,000 mg PO q6h PRN.
Oxycodone: 5 mg PO q4–6h PRN severe pain; use short course if needed.
No specific ED medication repairs the rupture; management is immobilization, pain control, and timely orthopedic referral.

High-Yield Pearls

Distal biceps rupture causes greatest weakness in supination, not just elbow flexion.
Proximal rupture often creates a visible Popeye deformity and is usually less urgent.
Distal rupture is time-sensitive because tendon retraction makes delayed repair harder.

Board Question

Which exam finding is most suggestive of distal biceps tendon rupture?

AWeak shoulder abduction
BInability to hook the distal biceps tendon in the antecubital fossa
CPain over the lateral epicondyle with wrist extension
DNumbness over the deltoid

Reveal answer

Correct: B

The hook test assesses integrity of the distal biceps tendon. Distal rupture classically causes antecubital pain, ecchymosis, and weakness with supination.

Recent Literature

Review or guideline Treatment of distal biceps tendon rupture: why, when, how? Analysis of literature and our experience
Musculoskelet Surg, 2015 · cited 28×
Recent clinical Brachial artery thrombosis secondary to fixation screw pullout: Case report
Radiol Case Rep, 2022 · cited 1×

Full text · open access

3 of 4

Psoas Abscess

Psoas abscess is an occult, potentially life-threatening deep infection that can mimic back pain, hip pain, renal colic, or abdominal pathology; delayed...

At the Bedside

Types
Primary: hematogenous spread, often Staphylococcus aureus.
Secondary: contiguous spread from GI/GU/spine sources, e.g., Crohn disease, diverticulitis, appendicitis, vertebral osteomyelitis/discitis, renal infection, postoperative infection.
Risk factors
Diabetes, IV drug use, immunosuppression, HIV, renal failure, malignancy.
Crohn disease, recent abdominal/spine surgery, spinal infection.
Symptoms
Fever, flank/back/abdominal/groin/hip pain.
Limp, malaise, weight loss.
Pain may worsen with hip extension.
Classic triad of fever, back pain, limp is uncommon.
Exam
Ill appearance or subtle findings.
Flank, lower abdominal, paraspinal, or hip tenderness.
Pain with passive hip extension.
Patient may hold hip flexed to reduce psoas stretch.
Evaluate for neurologic deficits if spinal source possible.
Workup
Labs:
CBC, CMP.
ESR/CRP often elevated.
Lactate if septic.
Blood cultures x2 before antibiotics if this does not delay care.
UA/urine culture if GU source possible.
Imaging:
CT abdomen/pelvis with IV contrast is typical ED test of choice.
MRI if concern for spinal epidural abscess, discitis, or vertebral osteomyelitis.
Ultrasound has limited sensitivity but may help in selected patients.
Initial ED management
Assess for sepsis: IV access, fluids, lactate, cultures, early broad-spectrum antibiotics.
Treat pain and nausea.
Identify source: GI, GU, spine, bacteremia, postoperative.
Definitive therapy
Antibiotics plus drainage for many cases.
Percutaneous CT-guided drainage commonly first-line if accessible.
Surgical drainage if multiloculated, large, inaccessible, failed percutaneous drainage, or requires operative source control.
Disposition
Most patients require admission.
ICU if septic shock, significant organ dysfunction, or unstable.
Consult general surgery, interventional radiology, infectious disease, and/or spine surgery depending on source.

A Classic Presentation

A 58-year-old man with diabetes and Crohn disease presents with 1 week of fever, right lower back pain, and limp. He holds his right hip flexed and has pain with passive hip extension. Labs show leukocytosis and elevated CRP. CT abdomen/pelvis with IV contrast demonstrates a right psoas abscess adjacent to inflamed terminal ileum. Blood cultures are obtained, vancomycin plus piperacillin-tazobactam is started, and he is admitted for IR drainage and surgical evaluation.

Study Directive

Create a differential for fever + back/hip pain: psoas abscess, septic arthritis, epidural abscess, pyelo, renal stone, osteomyelitis.
Review CT images of iliopsoas abscess and identify the psoas muscle anatomy.
Memorize empiric antibiotic structure: MRSA coverage + gram-negative/anaerobic coverage.
Practice saying the disposition plan: “admit, cultures, IV antibiotics, IR/surgery for drainage/source control.”

Key Medications

Empiric therapy should cover S. aureus including MRSA, gram-negatives, and anaerobes if secondary GI/GU source possible. Tailor to local resistance and source.
Vancomycin: 20–25 mg/kg IV loading dose for severe infection, then pharmacy-guided dosing by AUC/trough and renal function.
Plus one of:
- Piperacillin-tazobactam: 4.5 g IV q6h or extended infusion per institutional protocol.
- Cefepime: 2 g IV q8–12h depending on renal function plus metronidazole 500 mg IV/PO q8h for anaerobic coverage.
- Ceftriaxone: 2 g IV q24h plus metronidazole 500 mg IV/PO q8h if less concern for Pseudomonas.
If severe beta-lactam allergy: regimen varies; consider vancomycin plus aztreonam plus metronidazole, but check institutional guidance/ID.
Sepsis fluids: balanced crystalloid or normal saline 30 mL/kg IV for septic shock or significant hypoperfusion.
Analgesia
- Morphine: 4 mg IV q10–15 min PRN severe pain; titrate carefully.
- Hydromorphone: 0.5–1 mg IV q15–30 min PRN severe pain.

High-Yield Pearls

Pain with hip extension occurs because stretching the inflamed psoas worsens symptoms.
Primary psoas abscess is often S. aureus; secondary abscess needs broader GI/GU coverage.
If back pain plus fever plus neurologic findings: think beyond psoas — evaluate for spinal epidural abscess with MRI.

Board Question

A patient with fever, back pain, limp, and pain with passive hip extension has CT evidence of a psoas abscess. What is the most appropriate next step?

ADischarge with oral cephalexin
BNSAIDs and outpatient physical therapy
CIV broad-spectrum antibiotics and admission for drainage/source control
DImmediate thrombolysis

Reveal answer

Correct: C

Psoas abscess usually requires admission, IV antibiotics, and drainage/source control. Oral antibiotics alone are inadequate for most clinically significant abscesses.

Recent Literature

Review or guideline Management of Staphylococcus aureus Bacteremia: A Review
JAMA, 2025 · cited 79×
Recent clinical Pyogenic spondylitis and bilateral psoas abscess caused by Streptococcus agalactiae sequence type 283: A case acquired in Vietnam prior to the 2015 Singapore outbreak
J Infect Chemother, 2026

4 of 4

Radial Nerve Palsy

Radial nerve palsy can signal humeral shaft fracture, compressive neuropathy, posterior interosseous nerve syndrome, or a central neurologic process;...

At the Bedside

Anatomy / motor function
Radial nerve innervates wrist/finger extensors and triceps.
Sensory distribution includes dorsal radial hand, especially first dorsal web space.
Posterior interosseous nerve is primarily motor and typically spares sensation.
Common causes
Compression: “Saturday night palsy,” crutch palsy.
Humeral shaft fracture, especially spiral fracture.
Elbow trauma/dislocation.
Laceration/penetrating injury.
Iatrogenic/postoperative.
Lead poisoning or systemic neuropathy, less common.
Stroke mimic if broader deficits.
History
Trauma, fall, intoxication/sleep compression, crutch use.
Onset timing: sudden vs progressive.
Neck pain/radicular symptoms.
Weakness pattern, sensory symptoms.
Occupational/repetitive supination-pronation.
Exam
Motor:
Wrist extension: “wrist drop.”
Finger MCP extension.
Thumb extension.
Triceps strength helps localize lesion proximal vs distal.
Sensory:
First dorsal web space is key autonomous radial nerve territory.
Reflex:
Brachioradialis reflex may be decreased.
Localize:
High radial nerve lesion: wrist drop + sensory loss ± triceps weakness.
Spiral groove compression: wrist/finger extension weakness, triceps often spared.
Posterior interosseous nerve palsy: finger/thumb extension weakness, often no sensory loss; wrist extension may be weak but with radial deviation due to preserved ECRL.
Check for compartment syndrome if trauma: severe pain, tense compartments, pain with passive stretch.
Workup
If trauma: x-rays of humerus/elbow/forearm as indicated.
If concern for stroke: neuro exam, glucose, stroke pathway imaging.
If compressive palsy with classic story and no trauma: imaging may not be needed.
EMG/NCS usually outpatient if symptoms persist, commonly after several weeks.
Consider labs only for systemic/toxic/metabolic causes.
ED management
Treat underlying injury.
Splint wrist in extension to preserve function and prevent contracture.
Analgesia.
Avoid ongoing compression.
Physical/occupational therapy referral when appropriate.
Disposition
Compressive neuropathy: outpatient follow-up; most improve over weeks to months.
Humeral shaft fracture with closed radial nerve palsy: ortho consult/follow-up; many neuropraxias recover spontaneously, but fracture management drives disposition.
Open fracture, penetrating trauma, vascular injury, progressive deficit, compartment syndrome, or nerve transection concern: urgent orthopedic/hand surgery consultation.
Central signs, aphasia, facial droop, ataxia, or upper motor neuron findings: evaluate for stroke/CNS lesion.

A Classic Presentation

A 31-year-old man wakes after sleeping intoxicated with his arm draped over a chair. He has wrist drop and difficulty extending his fingers but intact triceps strength. Sensation is decreased over the first dorsal web space. There is no trauma and no central neurologic deficit. He is diagnosed with compressive radial neuropathy at the spiral groove, placed in a wrist extension splint, counseled to avoid compression, and referred for outpatient follow-up.

Study Directive

Draw radial nerve motor/sensory distribution, highlighting first dorsal web space.
Practice localization: high radial nerve vs spiral groove vs posterior interosseous nerve.
Review humeral shaft fracture x-rays and associated radial nerve risk.
Memorize red flags requiring urgent consult: open injury, vascular compromise, compartment syndrome, penetrating trauma, progressive deficit.

Mechanism Pearl of the Day: Today’s topics all hinge on structure-function correlation: small alignment errors in phalanx fractures disrupt tendon mechanics, biceps tendon location determines supination/flexion loss, psoas inflammation causes pain with hip extension, and radial nerve lesion level predicts the pattern of wrist/finger extension and sensory loss.

Key Medications

Acetaminophen: 650–1,000 mg PO q6h PRN.
Ibuprofen: 400–600 mg PO q6h PRN if no contraindications.
Naproxen: 500 mg PO once, then 250–500 mg PO BID PRN.
Oxycodone: 5 mg PO q4–6h PRN severe traumatic pain; short course only.
Neuropathic agents such as gabapentin are not usually started emergently for isolated acute palsy; outpatient management varies.

High-Yield Pearls

“Wrist drop” after sleeping on an arm is classic spiral groove radial neuropathy.
Posterior interosseous nerve palsy is mostly motor and usually has no sensory loss.
Radial nerve palsy with humeral shaft fracture is common and often neuropraxic, but open injury or transection concern needs urgent surgical evaluation.

Board Question

Which sensory area is most useful for testing radial nerve function?

AVolar tip of the index finger
BVolar tip of the small finger
CFirst dorsal web space
DMedial forearm

Reveal answer

Correct: C

The first dorsal web space is the autonomous sensory territory of the radial nerve. The index fingertip is median nerve, the small fingertip is ulnar nerve, and the medial forearm is medial antebrachial cutaneous nerve.

Recent Literature

Review or guideline Radial nerve compression: anatomical perspective and clinical consequences
Neurosurg Rev, 2023 · cited 59×

Full text · open access
Recent clinical Emergency Nursing Assessment in a Patient With a Hand Arteriovenous Fistula Caused by a Fishbone: A Case Report
J Emerg Nurs, 2026

TheDaily Differential

Phalanx Fractures

At the Bedside

Study Directive

Recent Literature

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Proximal and Distal Biceps Tendon Rupture

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