In a woman with isolated lower rib pain that worsens with pressure and a normal right upper quadrant (RUQ) ultrasound, what is the most likely diagnosis and appropriate initial management?

Musculoskeletal Rib Pain (Slipping Rib Syndrome or Painful Rib Syndrome)

This presentation is most consistent with slipping rib syndrome or painful rib syndrome—a musculoskeletal condition caused by hypermobility of the lower ribs (8-12) that produces pain worsening with compression, and requires no imaging beyond the normal ultrasound already obtained.

Clinical Diagnosis

The key diagnostic features strongly point to a musculoskeletal etiology rather than intra-abdominal pathology:

• Pain worsening with compression is pathognomonic for painful rib syndrome, which consists of three features: pain in the lower chest or upper abdomen, a tender spot on the costal margin, and reproduction of pain on pressing the tender spot 1
• The normal RUQ ultrasound effectively excludes acute cholecystitis, which is the primary diagnostic consideration for RUQ pain and for which ultrasound is the initial imaging study of choice 2
• Slipping rib syndrome is caused by hypermobility of the floating ribs (8-12) which are not connected to the sternum, and pain occurs from impingement of the intercostal nerve as the rib tip slips under the adjacent rib 3, 4

Specific Physical Examination Maneuver

Perform the "hooking maneuver" to confirm the diagnosis:

• Hook your fingers under the lower costal margin and pull anteriorly—this reproduces the pain in slipping rib syndrome 3, 4
• Systematic firm palpation of the entire costal margin should identify a specific tender spot that reproduces the patient's pain 1
• The diagnosis is entirely clinical and requires no further imaging 3, 1, 4

Why This Diagnosis is Frequently Missed

This condition accounts for 3% of new referrals to gastroenterology clinics but remains underdiagnosed 1:

• 43% of patients undergo extensive investigation before diagnosis, including unnecessary cholecystectomies in some cases 1
• Patients report months to years of typical pain symptoms and unnecessary tests prior to diagnosis 4
• The condition is safe to diagnose clinically and requires no investigation beyond excluding acute pathology 1

Management Algorithm

Initial conservative management should be implemented immediately:

• Provide reassurance that this is a benign musculoskeletal condition with no serious underlying pathology 3, 4
• Advise avoiding postures and movements that worsen pain (typically twisting, bending, or reaching movements) 3, 5
• Prescribe NSAIDs or analgesics for symptomatic relief 3
• Consider physical therapy focused on posture correction 3, 5

For refractory cases (if conservative management fails after 4-6 weeks):

• Intercostal nerve block can provide diagnostic confirmation and therapeutic relief 3, 4
• Surgical resection of the slipping rib cartilages is the definitive treatment, with good results for pain relief in cases unresponsive to conservative measures 4
• Rib stabilization is an emerging option for recurrent symptoms after initial surgery 4

Alternative Imaging Consideration

Dynamic ultrasound can confirm the diagnosis in difficult cases:

• Dynamic flow ultrasound of the lower chest can demonstrate slipping of the lowest rib over the next lowest rib during movement 3
• This is helpful for confirmation when the clinical diagnosis is uncertain, but is not necessary when the hooking maneuver is clearly positive 4

Critical Pitfalls to Avoid

• Do not order CT or MRI—these imaging modalities are consistently negative in slipping rib syndrome and expose the patient to unnecessary radiation and cost 3, 5
• Do not assume intra-abdominal pathology when pain is clearly reproducible with palpation of the costal margin—the normal ultrasound has already excluded the primary RUQ pathologies 2, 1
• Do not refer for further gastroenterology workup once the diagnosis is established, as this leads to unnecessary procedures and testing 1
• Do not dismiss the patient's pain—while benign, this condition can be debilitating, and 70% of patients still have pain at 4-year follow-up, though most learn to manage it 1

Long-term Prognosis

• Most patients learn to live with residual symptoms through activity modification and postural awareness 1, 5
• All further investigations in followed patients were negative except for incidental findings unrelated to the rib pain 1
• The condition is not associated with serious morbidity or mortality 1