The human pelvis is a basin-shaped complex of bones that connects the trunk to the lower limbs. It is composed of four bones: the sacrum, coccyx, and two large hip bones, also known as innominate or coxal bones. This structure supports the upper body and provides stability. The pubis is a component of each hip bone, contributing to the pelvis’s overall architecture.
Identifying the Pubis Location
The pubis is located at the front of the human body, in the lower abdomen. It is the anterior portion of each hip bone. Two pubic bones, one on each side, meet in the midline of the body.
These two pubic bones connect at the pubic symphysis, a joint positioned directly in front of the bladder. This cartilaginous joint unites the pubic bones. The pubis also articulates with the sacrum and femur as part of the hip bone, which forms the hip joint with the head of the femur.
Structure of the Pubic Bone
Each hip bone includes a pubis, the smallest of the three bones that fuse to form it; the others are the ilium and ischium. The pubis has three main parts: the body, the superior ramus, and the inferior ramus. The body is the central portion, where the two pubic bones join at the pubic symphysis.
Extending from the body are the two rami, which are like branches. The superior ramus extends upwards and sideways towards the ilium and ischium, forming part of the acetabulum, the hip joint socket. The inferior ramus projects downwards and sideways, joining the ischium. Between the superior and inferior rami lies a large opening called the obturator foramen, mostly covered by a membrane, allowing passage for nerves and blood vessels.
Key Functions of the Pubis
The pubis plays several roles within the pelvic girdle, contributing to protection and movement. It provides structural support for the intestines, bladder, and internal reproductive organs, forming an anterior bony border that offers protection.
The pubis also serves as an attachment point for muscles and ligaments. Abdominal muscles, such as the rectus abdominis, and various thigh muscles, including the adductors, attach to the pubis, facilitating trunk and lower limb movement and stability. The pubic symphysis, while generally having limited movement, can become more flexible during pregnancy, allowing the pelvic bones to widen slightly to assist in childbirth.