Ischial tuberosity

Specific risks

Ischial tuberosity pressure injuries most commonly occur during sitting. The ischial tuberosities bear the majority of seated body weight in a neutral sitting posture on a flat, firm surface, as they are the lowest point of pelvic contact.

Surfaces and activities that can increase pressure, shear, and friction over the ischial tuberosities include:

• Cushions, particularly if inadequate, worn, or inappropriate for the user’s needs
• Other seating surfaces such as sports chairs, car seats, hard floors, dining chairs, lounge chairs, outdoor furniture, tub transfer benches, and static shower chairs
• Transfers, especially if not well controlled or involve sliding
• Postural issues, including pelvic obliquity or scoliosis
• Infrequent or ineffective pressure relief
• Tight clothing, incontinence pads, or underwear seams
• Muscle wasting or unintentional weight loss, which reduces soft tissue protection
• Mattresses, particularly if prolonged time is spent in bed without repositioning
• Moisture and microclimate changes from heat, humidity, incontinence, or occlusive clothing, which can lead to rashes or skin breakdown that worsens with sitting
• Asymmetrical pelvic loading, such as frequent use of the dominant hand (e.g. for computer work or power wheelchair use), which may cause the pelvis to drop more on one side

These areas should be assessed by palpating for ‘boggy’, soft, or tender tissue, which may indicate early tissue damage.