Normal Anatomy of the Hip
The hip joint is a ball-and-socket type of joint. It is one of the simplest types of joint in terms of moving parts. This joint is strong and stable but does have a somewhat limited range of motion. The hip joint is made up of just two bones: the femur (thigh bone), and the pelvis (os coxae).
The femur is a long, sturdy bone that has two major jobs. It forms part of the hip joint at its upper end, and forms part of the knee joint at its lower end. The upper end of the femur has a structure that looks sort of like a ball-on-a-stick. The ball part is called the head of the femur, and the stick part is called the neck. The ball part of the femur fits into the socket part of the pelvis to form the hip joint.
The pelvis is usually what people think of when talking about the hip. The pelvis is a large bony structure divided into two halves: left and right. Each half of the pelvis is made up of 3 sub-structures called the ilium, ischium, and pubis.
The ilium is the part of the pelvis that you normally place your hands on when putting your hands on your hips. It is easily felt on most people as the curved bone that goes from the front to the back of the body at the waist.
The ischium is the part of the pelvis that you sit on. It can be felt on most people by sitting on your hands and gently moving your hips back and forth.
The pubis is also called the pubic bone. This can be felt by finding your belly button and moving down the lower abdomen until you feel a bony spot several inches below your waistline.
These three structures are all connected together into one solid piece and form one entire half of your pelvis. The two sides of your pelvis are simply mirror images of each other.
The reason for this detailed explanation of hip anatomy is to help describe a very important structure of the hip called the acetabulum. Acetabulum is a Latin word meaning vinegar cup.
Early anatomy doctors noticed that the shape of the hip socket resembled a cup, so they gave the hip socket the Latin name acetabulum. The acetabulum is formed in the location where the 3 hip structures (ilium, ischium, and pubis) come together.
The cup shape of the acetabulum allows the ball shape of the thigh bone to fit inside to form the hip joint. A simple way to imagine this joint is to make a fist with one hand and place your other hand over the fist and grasp it. The surfaces where the bones meet in the joint are covered in a special type of cartilage called articular cartilage. This cartilage is responsible for reducing friction in the joint as well as absorbing some of the shock and stresses in the joint that occurs during movement and activities.
Injuries and Problems of the Hip Joint
As mentioned above, the hip joint is strong and stable, but the down side is that it does not have a large range of motion. Also, the hip joint is responsible for helping to hold the weight of our upper body when walking, running, climbing stairs, and during other activities. This joint can be subject to a lot of stress, wear and tear, and injuries which can lead to damage to the cartilage and the eventual formation of arthritis.
Common injuries to the hip joint are fractures, wear and tear arthritis, rheumatoid arthritis, infections, and others. Hip replacement surgery is typically performed in cases where injury and arthritis has lead to damage to the joint surfaces leading to the “bone on bone” condition. You may also need hip replacement if you break a bone or bones in the hip. A common type of break occurs in the neck of the femur, often due to falling down.
Types of Surgical Interventions for the Hip
There are generally two types of hip replacement surgery: Traditional Hip Replacement and Minimally Invasive Hip Replacement. Your surgeon will discuss with you the particular details pertaining to your surgical procedure.
This page is for information purposes only, and describes general information. You should always talk to your physician regarding specific details of your surgery.