In this anatomy lesson, I’m going to cover the femur bone, which is the only bone that makes up the thigh. In fact, the word femur comes from a Latin word that literally means “thigh.”
The femur is part of the appendicular skeleton, and this bone is classified as a long bone, which makes sense considering the femur just so happens to be the longest, biggest, and strongest bone in the human skeleton.
So let’s review the anatomy of the femur bone.
- Head – First, we have this large ball-like structure on the superior portion of the femur, which is called the head. Why does it have this ball shape? It’s going to form a ball-and-socket synovial joint with the acetabulum of the hip bone.
- Fovea capitis – There is a tiny pit on the head of the femur, called the fovea capitis, which allows for the attachment of a ligament called the “ligament of the head of the femur.” (Hey, at least you’ll know where that ligament is located!) This ligament attaches to the sides of the acetabular notch.
- Neck – The neck of the femur attaches the head to the shaft. It is surrounded by the joint capsule of the hip.
- Greater trochanter – There are two trochanters, or irregular bony protuberances, on the femur. The greater trochanter is the larger bony process located laterally on the femur, and it allows for the attachment of muscles such as the piriformis, gluteus medius, gluteus minimus and vastus lateralis. The greater trochanter can be felt on the lateral side of the thigh (near the hip), and it serves as a landmark when fitting a patient for a cane. This is also a site that you’ll want to monitor for bedsores or pressure ulcers when a patient is lying on their side for an extended period.
- Lesser trochanter – The lesser trochanter is smaller and located more medially on the posterior region of the femur, and it allows for the attachment of muscles such as the psoas major and iliacus.
- Intertrochanteric line – The intertrochanteric line connects the trochanters on the anterior side of the femur, and it allows for the attachment of the joint capsule of the hip, as well as the iliofemoral ligament.
- Intertrochanteric crest – The intertrochanteric crest is a ridge that connects the greater and lesser trochanter on the posterior side, and it allows for the attachment of the quadratus femoris.
- Gluteal tuberosity – There is a rough, ridged line below the intertrochanteric crest, which is called the gluteal tuberosity. As the name suggests, it allows for the attachment of the gluteus maximus, which is your butt muscle. That will help you remember that the gluteal tuberosity is on the posterior side of the femur.
- Linea aspera – The rough line continues down the posterior side of the shaft, and is called linea aspera, which is a Latin word that literally means “rough line.” It allows for the attachment of various muscles: vastus medialis, vastus lateralis, adductor magnus, biceps femoris, iliacus, pectineus, adductor brevis, and adductor longus.
- Medial and lateral supracondylar lines – The linea aspera forks off into a medial and lateral supracondylar lines, which serve as attachment points for muscles: adductor magnus, vastus medialis, and plantaris. Remember, medial means toward the midline of the body, and lateral means away from the midline of the body (or toward the side of the body).
- Lateral epicondyle – The lateral supracondylar line is going to extend down toward the lateral epicondyle, which allows the attachment of the fibular collateral ligament of the knee. The prefix “epi” means this structure is above, near, or upon the lateral condyle.
- Medial epicondyle – The medial epicondyle is located above the medial condyle (hence the prefix “epi”), and it provides attachment of the adductor magnus and gastrocnemius muscles.
- Lateral and medial condyles – The lateral and medial condyles are going to articulate (form a joint) with the patella and tibia bone of the leg, creating the tibiofemoral joint. What is a condyle? It’s a rounded projection that’s going to form a joint.
- Adductor tubercle – The adductor tubercle is a small bump that rests on the top of the medial condyle, which allows the insertion of the tendon of the adductor magnus.
- Patellar surface – On the anterior side of the femur you have the patellar surface, which is a smooth depression that provides articulation with the patella bone (also called the kneecap).
- Intercondylar notch – On the posterior side of the femur, there is a notch separating the medial and lateral condyles (hence the prefix “inter” which means between, and condylar, which relates to the condyles). This provides attachment of the anterior cruciate ligament (ACL) and the posterior cruciate ligament (PCL).