A 35-year-old man presents with a 6-month history of low back pain and stiffness. The pain began insidiously, is worst in the early morning lasting over 1 hour, improves with exercise, and worsens with rest. He also reports intermittent pain in his right heel. On examination, there is reduced lumbar spine mobility in all directions and tenderness over both sacroiliac joints. Schober's test shows only 2 cm expansion (normal >5 cm).

Which investigation is MOST likely to confirm the diagnosis?

A 55-year-old woman with a history of breast cancer treated 3 years ago presents with severe mid-thoracic back pain for 3 weeks. The pain is constant, present day and night, and not relieved by rest or position change. She reports unintentional weight loss of 5 kg over the past 2 months. On examination, there is point tenderness over T7 spinous process. Neurological examination of the lower limbs is currently normal.

What is the MOST appropriate next step?

A 62-year-old woman presents with gradually worsening right knee pain over 18 months. The pain is worse at the end of the day and after prolonged activity. She experiences brief morning stiffness lasting about 15 minutes. On examination, there is a small effusion, crepitus on movement, bony enlargement of the joint margins, and reduced range of motion. Her BMI is 32 kg/m².

What is the FIRST-LINE management approach for this patient?

A 45-year-old woman presents with pain and stiffness in both hands for 3 months. The stiffness is worst in the morning, lasting approximately 2 hours, and improves with activity. On examination, there is symmetrical swelling and tenderness of the metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints of both hands. The distal interphalangeal (DIP) joints are spared.

Which pattern of joint involvement is MOST consistent with this presentation?

A 50-year-old woman presents with right shoulder pain for 6 weeks. The pain is located over the lateral aspect of the upper arm, worse when reaching overhead or behind her back. She works as a cleaner. On examination, there is a painful arc between 60-120° of abduction. Passive range of motion is full. Resisted abduction and external rotation are painful and slightly weak. Neer's and Hawkins-Kennedy tests are positive.

What is the MOST likely diagnosis?

A 58-year-old diabetic man presents with progressively worsening right shoulder stiffness over 4 months. He now has difficulty combing his hair and fastening his seatbelt. Pain is moderate but constant. On examination, there is marked global restriction of both active AND passive range of motion: external rotation is limited to 10° (normal 60-90°), abduction to 80°, and internal rotation is severely restricted. There is no significant weakness.

What is the MOST likely diagnosis?

A 40-year-old man presents with sudden onset of severe low back pain radiating down his left leg to the foot. The pain started 2 days ago after lifting furniture. The leg pain is worse than the back pain. He reports numbness over the top of his foot and difficulty lifting his foot while walking. On examination, straight leg raise is positive at 30° on the left. There is weakness of ankle dorsiflexion and great toe extension on the left. The ankle jerk is preserved, but sensation is reduced over the dorsum of the foot and first web space.

Which nerve root is MOST likely affected?

A 48-year-old woman presents with neck pain and right arm pain for 2 weeks. The arm pain radiates from the neck down the lateral arm to the thumb and index finger. She reports tingling in these fingers. On examination, neck extension and rotation to the right reproduces the arm symptoms (positive Spurling's test). Biceps reflex is diminished on the right. There is weakness of elbow flexion and wrist extension. Sensation is reduced over the lateral forearm and thumb.

Which cervical nerve root is MOST likely compressed?

A 32-year-old woman presents with acute onset of severe left knee pain, swelling, and redness since yesterday. She cannot weight bear. She has no history of trauma. She reports feeling feverish. On examination, temperature is 38.5°C, the left knee is hot, swollen, and extremely tender with any movement. There is a tense effusion. She had a urinary tract infection treated with antibiotics 2 weeks ago.

What is the MOST important immediate step?