E5504. Ischial Tuberosity: Anatomy, Function, Pathology, Treatment
  1. Zachary Miller; University of Washington
  2. Arash Azhideh; University of Washington
  3. Mikaela Brandt-Fontaine; University of Minnesota
  4. Joseph Voth; University of Washington
  5. Nitin Venugopal; University of Washington
  6. Atefe Pooyan; University of Washington
  7. Majid Chalian; University of Washington
The ischium is a vital part of the pelvis. This exhibit reviews its anatomy, particularly the ischial tuberosity and its tendons, ligaments, bursae, and neurovasculature. Teaching points are emphasized using illustrations, cadaveric photos, and radiologic images. The exhibit also showcases various pathologies near the ischial tuberosity, along with treatments.

Educational Goals / Teaching Points
Review the osteology of the ischium with a focus on the ischial tuberosity. Describe the anatomy and function of structures related to the ischial tuberosity. Review pathology and management of conditions involving the ischial tuberosity and related structures. Avulsion of the ischial apophysis, often caused by acute trauma, is a significant yet underrecognized condition. Swift diagnosis is crucial, and early imaging aids accurate assessment. Surgical intervention, particularly for fragment displacement exceeding 2 cm, can enhance return to activity. Notably, fusion of the ischial apophysis typically occurs between 18 and 25 years old. Additionally, new research suggests benefits of early surgical repair even for < 2 cm displacements. Delayed treatment can lead to complications like nonunion, fibrosis, osseous overgrowth, and chronic pain, with strategies like fragment excision and hamstring tendon repair for chronic nonunion. Ischiogluteal bursitis, often caused by prolonged sitting, repetitive motion, or vibrations, can trigger intrabursal hemorrhage due to shearing forces. This condition presents as hip/buttock pain, potentially radiating and causing referred pain from sciatic or posterior cutaneous nerve involvement. Accurate evaluation is best achieved using MRI or ultrasound to assess inflammation and associated issues.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Avulsion of the apophysis is rare but notable in young athletes, typically stemming from acute trauma. Often misdiagnosed as a hamstring injury (around 40% misdiagnosis rate), the correct diagnosis can take an average of 42 weeks if overlooked. Early imaging can aid timely identification. Surgery is indicated for displacements over 2 cm, resulting in better sports return compared to conservative methods. Notably, an initial misdiagnosis reduces return rates, even with subsequent surgery, highlighting the intricate challenge of managing this condition in young athletes. The ischiogluteal bursa is positioned between the ischial tuberosity and the gluteus maximus muscle, becoming apparent during sitting or hip flexion. Excessive sitting, repetitive motions like cycling, and exposure to vibrations can lead to ischiogluteal bursitis.

In summary, understanding the ischial tuberosity's role in musculoskeletal function is crucial. Avulsion injuries, though rare, warrant prompt diagnosis and consider evolving surgical criteria. Ischiogluteal bursitis, stemming from modern lifestyles, highlights the need for accurate diagnostics. Altogether, these insights emphasize the link between anatomical knowledge and improved musculoskeletal health.