Inferior pubic ramus spreads out from the lower as well as lateral part of the body of pubis and on the medial side of the obturator foramen creates ischiopubic ramus by combining with ramus of ischium.
Structure and Attachments
The inferior pubic ramus goes downwards and laterally from the lower part of the body of pubis. Structurally it is flat and compressed; it blends with the inferior ramus of the ischium, and encloses the obturator foramen as a result and creates the pubic arch.
Anteriorly following muscles originate from it:
Medial surface has smooth border, while its lower border has the anterior part of the crus penis and the arcuate or subpubic ligament attached to it and is round or relatively turned outwards.
Pubic Arch and Ischiopubic Ramus
The pubic arch is formed by the pubic symphysis, along with its bodies as well as inferior pubic rami of the adjacent pubic bones. The inferior pubic ramus spreads out downward and connects to the ischial ramus. Together, they create ischiopubic ramus, which ranges from the pubic body to the ischial tuberosity. While the ischiopubic rami from each sides merges at the pubic symphysis, an inverted V-shape called the subpubic angle is formed.
In the studies of pediatric pelvic fractures 18% of pediatric pelvic fractures consisted of fractures of the ipsilateral superior as well as inferior pubic rami. Even though these fractures are normally stable, they may be related to injuries of the abdominal viscera, specifically to the genitourinary system like bladder rupture.
Stress fractures occur in teenagers and young adults because of chronic, repetitive stress on a bone or during pregnancy in the last trimester and are rarely found in small children. Stress fractures of the pubis are rare, but a small amount of stress fractures, mainly the fractures of inferior pubic rami, have been reported. The inferior pubic area shows chronic symptoms and pain increased by stress.