High Yield MSK Review Lecture Notes

Overview

• Covers muscle injuries and nerve injuries, focusing on conditions and associated symptoms.
• Includes management and characteristic features of various musculoskeletal and peripheral nerve injuries.
• Discussion based on clinical vignettes.

Muscle Injuries

Rotator Cuff Injuries

• Supraspinatus Muscle Injury:
  • Trouble abducting arm first 15°
  • Abnormal empty and full can test
  • Innervated by suprascapular nerve
• Deltoid Muscle Injury:
  • Trouble abducting 15-90°
  • Innervated by axillary nerve
• Serratus Anterior Muscle Injury:
  • Trouble abducting over 90°
  • Winged scapula
  • Innervated by long thoracic nerve (C5, C6, C7)

Nerve Injuries

Upper Limb Nerve Injuries

• Axillary Nerve Injury:
  • Affected by humeral neck fracture
  • Loss of sensation over deltoid region
  • Accompanied by posterior circumflex artery
• Radial Nerve Injury:
  • Mid-shaft humerus fracture leads to wrist drop
  • Associated with deep brachial artery
• Median Nerve Injury:
  • Distal humerus fracture
  • Loss of sensation over thenar eminence and lateral 3.5 fingers
• Ulnar Nerve Injury:
  • Claw hand from distal ulnar nerve injury

Special Conditions

• Erb's Palsy (C5, C6):
  • Arm abducted, medially rotated, extended, pronated
• Klumpke's Palsy (C8, T1):
  • Claw hand after childbirth or fall
  • Lower trunk injury
• Thoracic Outlet Syndrome:
  • Atrophy of hand muscles, extra cervical rib

Lower Limb Nerve Injuries

• Common Fibular (Peroneal) Nerve Injury:
  • Trauma to lateral leg, issues with foot eversion, dorsiflexion
• Tibial Nerve Injury:
  • Knee or ankle injury, issues with plantar flexion, sensation at sole of foot
• Superior Gluteal Nerve Injury:
  • Trendelenburg sign
• Inferior Gluteal Nerve Injury:
  • Difficulty climbing stairs after posterior hip dislocation

Conditions and Syndromes

Specific Conditions

• Scaphoid Fracture:
  • Fall on outstretched hand; avascular necrosis risk
• Carpal Tunnel Syndrome:
  • Median nerve entrapment
• Tennis Elbow (Lateral Epicondylitis)
• Golfer's Elbow (Medial Epicondylitis)

Joint and Bone Disorders

• Rheumatoid Arthritis:
  • Symmetrical joint pain, auto-immune
• Osteoarthritis:
  • Joint pain with activity, bone deformities
• Gout vs. Pseudogout:
  • Gout: Negative birefringent crystals
  • Pseudogout: Positive birefringent crystals

Inflammatory and Autoimmune Disorders

• Systemic Lupus Erythematosus (SLE):
  • Multiple symptoms including joint pain, facial rash
• Sjogren's Syndrome:
  • Dry eyes, mouth, associated with lymphomas
• Scleroderma:
  • Skin tightening, Raynaud's phenomenon

Muscular Disorders

• Myasthenia Gravis:
  • Muscle weakness worsens with use, autoantibodies against acetylcholine receptors
• Lambert-Eaton Syndrome:
  • Muscle weakness improves with use, associated with small cell lung cancer

Injuries and Trauma

• Unhappy Triad:
  • Common sports injury involving ACL, MCL, and medial meniscus
• Prepatellar Bursitis:
  • Inflammation from excessive kneeling
• Compartment Syndrome:
  • Increased pressure in fascial compartment causing severe symptoms

Bone Growth Disorders

• Osteoporosis vs. Osteopetrosis:
  • Osteoporosis: Normal calcium/phosphate, frail bones
  • Osteopetrosis: Thick bones due to osteoclast defects

Important Notes

• Remember key anatomical landmarks for nerve blocks and injury prevention.
• Differentiate conditions with similar clinical presentations using specific tests and knowledge of underlying anatomy.

Note: Always cross-reference these notes with your textbooks and practice clinical scenarios to enhance understanding and retention.