Pubis (bone)

Structure of the Pubis Bone

The pubis bone is one of the three bones that make up the pelvis, along with the ilium and ischium. It is located in the lower part of the pelvic girdle, and its structure plays a crucial role in supporting the weight of the upper body and providing attachment points for various muscles and ligaments.

Anatomy

The pubis bone consists of a body and two branches, known as the superior and inferior pubic rami. The body of the pubis bone is located in the midline of the pelvis, forming the anterior part of the pubic arch. It is a flat, triangular-shaped bone that curves inward and downward, resembling the shape of a shallow cup.

The superior pubic ramus extends superiorly from the body of the pubis bone, connecting it to the ilium bone. It is a thick and strong bone that contributes to the stability of the pelvis. On the other hand, the inferior pubic ramus extends inferiorly from the body of the pubis bone, joining with the ischium bone. It is relatively thinner and less prominent compared to the superior pubic ramus.

Articulations

The pubis bone articulates with the other two bones of the pelvis, namely the ilium and ischium. At the superior aspect, the pubis bone forms the pubic symphysis, a cartilaginous joint that connects the two pubic bones together. This joint allows for a small amount of movement, which is important during childbirth and other activities that involve pelvic mobility.

The pubis bone also articulates with the sacrum, forming the sacroiliac joint. This joint is a synovial joint that connects the pelvis to the vertebral column, providing stability and transmitting forces between the upper body and the lower limbs.

Ligamentous Attachments

Several ligaments attach to the pubis bone, providing stability and support to the pelvis. The superior pubic ligament attaches to the superior pubic ramus, reinforcing the superior aspect of the pubic symphysis. The inferior pubic ligament attaches to the inferior pubic ramus, providing additional support to the pubic symphysis.

The pubic tubercle, a bony prominence located at the anterior aspect of the pubis bone, serves as an attachment point for the inguinal ligament. This ligament extends from the pubic tubercle to the anterior superior iliac spine, forming the floor of the inguinal canal.

Function

The pubis bone, along with the other bones of the pelvis, plays a crucial role in weight-bearing and locomotion. It provides a stable base for the upper body and supports the weight of the abdominal organs. The pubic symphysis allows for a small amount of movement, which is important during activities such as walking, running, and jumping.

The pubis bone also serves as an attachment site for various muscles involved in pelvic stability and movement. The adductor muscles, including the adductor longus, adductor brevis, and adductor magnus, originate from the pubis bone and help in bringing the legs together. The rectus abdominis muscle, which is responsible for flexing the trunk, attaches to the pubic symphysis via the pubic crest.

Clinical Significance

Injuries to the pubis bone can occur due to trauma or overuse, leading to conditions such as pubic symphysis dysfunction or pubic stress fractures. These conditions can cause pain and discomfort in the pelvic region, affecting daily activities and sports performance. Proper diagnosis and treatment are essential to manage these conditions effectively.

See Also

• Pelvis
• Ilium (bone)
• Ischium (bone)