What type of bone is the patella

Table of Contents Show

Spotlight Patella: Interesting facts about this simple yet complex structure in our knee.
The Long and the Short of It: The Five Types of Bones
1. Flat Bones Protect Internal Organs
2. Long Bones Support Weight and Facilitate Movement
3. Short Bones Are Cube-shaped
4. Irregular Bones Have Complex Shapes
5. Sesamoid Bones Reinforce Tendons
Is patella a flat bone?
Is patella a sesamoid bone?
Why is the patella considered a sesamoid bone?

Spotlight Patella: Interesting facts about this simple yet complex structure in our knee.

November 4, 2019 Blog Page, Front Page

Did you know ostriches are born with four kneecaps (patella)? The evolutionary reason for this is still not fully understood but theories include that it allows this heavy fast bird to straighten its knee faster thereby helping it to run faster. I have dedicated so much of my career to issues of the human patella. Many issues can arise from this small but fascinating bone. See below to learn some fun facts about this simple yet complex structure in our knees.

Ostrich knee X-ray

The patella is a roughly triangular shaped bone called a sesamoid bone from the Latin sesamun “sesame seed”. It is the largest of this type of bone in our body as compared to the tiny sesamoid bones in say our foot.
Babies are born with a patella made of cartilage instead of bone partly due to its flexibility for the birthing process
The patella slowly turns from cartilage to bone between the ages of 2-6 years old

Some people’s patella bone never fuses and so they may have two separate bones know as a bipartite patella. Rare genetic disorders cause some people to not develop a patella bone.
“The knee bone is connected to the thigh bone” – this is sort of true as the quadriceps tendon in your thigh attaches to the upper part of your patella and patella tendon below your patella attaches to your shin bone.
The patella sees an average of 2.5-3.5 times your body weight with stairs and up to 7-8 times your body weight with deep squat.
The patella is vital to protect the inner structures of your knee acting as a shield. The patella increases the leverage of the knee extensor (straightening) muscles, so they don’t need as much force to straighten the knee.
For such a small bone it is prone to injury including fractures, dislocations, patellofemoral syndrome and arthritis. Some people even have the patella removed due to severe injury or arthritis.

These are just some of the interesting facts about the patella and demonstrate how intricate and fascinating a structure it is in our bodies. Given that injuries to this bone and surrounding tendons, ligaments and joints are so common, it is important to properly manage these injuries to prevent damage to the surrounding structures as they are all interconnected. If you are experiencing issues of the patella or patellofemoral joint please visit the patellofemoral disorder section of my website to learn more.

By Dr. Beth Shubin Stein

adminSpotlight Patella: Interesting facts about this simple yet complex structure in our knee.11.04.2019

The patella is commonly referred to as the kneecap. It is a small, freestanding, bone that rests between the femur (thighbone) and tibia (shinbone). The femur has a dedicated groove along which the kneecap slides. As a form of protection, both bones also contain cartilage — strong, flexible tissue — in the areas near the patella.

The kneecap plays a vital role in how the knee bends, in addition to most motions that require movement of the leg. If the patella or the tendon associated with it becomes injured, a person will experience difficulty walking, running, standing, or engaging in athletic activity. If dislocated, the kneecap can no longer slide along the thighbone’s grooves, which can aggravate and damage cartilage on both the femur and the tibia.

Dislocation and other traumatic injuries are common among athletes and other people who are extremely physically active. Injuries tend to be more pronounced in high impact sports. For example, patella-related injuries are common in sports like football, mixed martial arts, and wrestling.

The Long and the Short of It: The Five Types of Bones

The human skeleton has a number of functions, such as protection and supporting weight. Different types of bones have differing shapes related to their particular function.

So, what are the different types of bones? How are they categorized?

There are five types of bones in the skeleton: flat, long, short, irregular, and sesamoid.

Let’s go through each type and see examples.

1. Flat Bones Protect Internal Organs

There are flat bones in the skull (occipital, parietal, frontal, nasal, lacrimal, and vomer), the thoracic cage (sternum and ribs), and the pelvis (ilium, ischium, and pubis). The function of flat bones is to protect internal organs such as the brain, heart, and pelvic organs. Flat bones are somewhat flattened, and can provide protection, like a shield; flat bones can also provide large areas of attachment for muscles.

2. Long Bones Support Weight and Facilitate Movement

The long bones, longer than they are wide, include the femur (the longest bone in the body) as well as relatively small bones in the fingers. Long bones function to support the weight of the body and facilitate movement. Long bones are mostly located in the appendicular skeleton and include bones in the lower limbs (the tibia, fibula, femur, metatarsals, and phalanges) and bones in the upper limbs (the humerus, radius, ulna, metacarpals, and phalanges).

3. Short Bones Are Cube-shaped

Short bones are about as long as they are wide. Located in the wrist and ankle joints, short bones provide stability and some movement. The carpals in the wrist (scaphoid, lunate, triquetral, hamate, pisiform, capitate, trapezoid, and trapezium) and the tarsals in the ankles (calcaneus, talus, navicular, cuboid, lateral cuneiform, intermediate cuneiform, and medial cuneiform) are examples of short bones.

4. Irregular Bones Have Complex Shapes

Irregular bones vary in shape and structure and therefore do not fit into any other category (flat, short, long, or sesamoid). They often have a fairly complex shape, which helps protect internal organs. For example, the vertebrae, irregular bones of the vertebral column, protect the spinal cord. The irregular bones of the pelvis (pubis, ilium, and ischium) protect organs in the pelvic cavity.

5. Sesamoid Bones Reinforce Tendons

Sesamoid bones are bones embedded in tendons. These small, round bones are commonly found in the tendons of the hands, knees, and feet. Sesamoid bones function to protect tendons from stress and wear. The patella, commonly referred to as the kneecap, is an example of a sesamoid bone.

Is patella a flat bone?

The patella is a flat triangular shaped bone that protects the knee joint and helps muscles move your leg more efficiently. A healthy patella glides up and down a groove at the end of your femur, pain free.

Is patella a sesamoid bone?

The patella is a sesamoid bone located in the major extensor tendon of the knee joint, in the hindlimb of many tetrapods. Although numerous aspects of knee morphology are ancient and conserved among most tetrapods, the evolutionary occurrence of an ossified patella is highly variable.

Why is the patella considered a sesamoid bone?

The patella is the largest sesamoid bone in the body. Sesamoids act like pulleys, providing a smooth surface for tendons to slide over, increasing the tendon's ability to transmit muscular forces. Sesamoid bones at the distal end of the first metatarsal bone of the foot.