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Hip, Hip, Hooray: Understanding Hip Osteoarthritis and Hip Replacements

Posted by Madison Oppenheim on Thu, Sep 15, 2016 @ 07:40 AM

Today's blog post is brought to you in part by the saying "you don't know what you have until it's gone."

Your hip is an essential joint that I'm sure you don't put much thought into during the day while you bend down to tie your shoe or get out of your chair for your three o'clock bathroom break. But neither of those activities would be possible without it. 


Do the Hula: Anatomy of The Hip

The hula hoop is a classic childhood activity seconded only by the limbo. When doing hula, you shake and shimmy until you drop the hoop and/or beat your competitor (I always made everything into a competition). Your hip enables you to shake your way to victory and beat Ashley, who is weak

Your hip is a ball-and-socket joint that gives you mobility in all directions: forward, backward, left, and right, as well as some rotation. It’s comprised of the pelvis and femoral head (upper part of femur). The femur articulates at a concave surface formed by the hip bones, called the acetabulum. 


The proximal head of the femur and acetabulum's surface is covered by articular cartilage that decreases friction and protects the bones.


As we get older, things start going south.

Osteoarthritis is something you’ve probably heard about, thrown around in conversations with your aunt, and unfortunately with age, it can be like a dark cloud, looming over your head and following you everywhere—even to your trip to the store for Q-tips. 

Osteoarthritis is sometimes referred to as "degenerative joint disease" because the cartilage on the surface of joints is worn away with wear-and-tear. This can cause pain and stiffness, and can make it difficult to complete daily tasks (e.g., the bathroom break mentioned above).


It’s a degenerative type of arthritis that usually occurs in people over age 50, but it may pop up in younger people, too. The cartilage in the joint wears away over time and becomes frayed and rough, exposing bone surfaces beneath, which causes the pain. 

Other symptoms include tenderness, stiffness, and pain (obviously). 

There are many risk factors that can cause osteoarthritis besides age, including a family history of osteoarthritis, a hip joint injury, obesity, and developmental dysplasia of the hip (improper hip joint formation at birth).

Although there’s no cure for osteoarthritis, there are some possible treatments for the pain and to improve your mobility. 

Lifestyle changes are an option that can protect your hip joint and slow the osteoarthritis process down. These include minimizing activities that will make it worse (take the elevator instead of the stairs), switching from high-impact to low-impact activities (from running to swimming), and losing weight, which reduces stress on the joint. 

Physical therapy can help improve range of motion and flexibility, as well as strengthen muscles in the hip and leg. 

There are also assistive devices like canes, crutches, and walkers that can improve mobility and can make you feel more independent. Long-handled reachers can help you pick up low things so you don't have to bend over and experience pain. 

There are also a variety of medications to treat pain: acetaminophen (over-the-counter pain reliever you can grab at your local drugstore), nonsteroidal anti-inflammatory drugs, which relieve pain and reduce inflammation, and corticosteroids, which are powerful anti-inflammatory drugs that can be taken orally or injected into the joint. 


Hip Op: Surgical Treatments

Hip hop, jazz, EDM, take your pick. After your pain is relieved you’ll want to get up and dance! 

If your doctor recommends surgery to treat your hip osteoarthritis, there are a few options.

An osteotomy is where either the femoral head or the socket is cut and realigned—this takes pressure off of the hip joint.

There’s also hip resurfacing, where the damaged bone and cartilage in the acetabulum are removed and a metal shell is placed instead. The femoral head is capped with a smooth metal covering to reduce friction.

The last option is a total hip replacement. Both the damaged acetabulum and the femoral head are removed and replaced with either metal, plastic, or ceramic joint surfaces to restore the hip's function. So basically you can become bionic (if you choose metal, talk to your doctor about your options). 




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Source: "Osteoarthritis of the Hip." OrthoInfo. Web. 21 Jul 2016. 

Topics: 3D skeletal system

Learn Muscle Anatomy: Bursae

Posted by Courtney Smith on Wed, Jul 30, 2014 @ 08:27 AM

The other day, I let my ten-year old niece play with Muscle Premium on my phone (while I watched cartoons). She kept making the model spin—around and around and around, like a ballerina, until she abandoned it for the muscle actions.

"Auntie," she said, and then didn't follow up with anything, completely engrossed in Elbow Flexion. When I prompted her, she looked up at me and whispered, as if confessing a secret, "Is it supposed to hurt?"

I asked her what she meant. She pointed to the moving model.

"Do bones rub against each other like that all the time? Because I feel like it should hurt."

I watched the animation for a bit—the olecranon of the ulna slid against the humerus's olecranon fossa, back and forth, flexed in a continuous loop. It did look a bit like they were rubbing together. Actually, if there wasn't something there acting as a cushion, moving the joints would be incredibly painful. Luckily, we're not that bad off.

"It doesn't hurt," I began, settling back to finish The Legend of Korra, "Because you have little pillows called bursae inside you that stop your bones from rubbing like that."

She turned her attention back to the TV and waited until the end of the episode to ask more. (My niece is polite like that.)

That was an actual exchange between me and my niece Em, who has an affinity for all things science and interesting. She's awesome.

Anyway, what I told her was the truth: bursae prevent our bones and muscles, particularly in the joints, from rubbing together and creating painful friction. Imagine trying to bend your knee without something to cushion the movement. Talk about ouch, right?

Muscle patella superficial subcutaneous prepatellar bursa knee synovial resized 600 

See those purple lumps in the picture? Those are bursae. They live between bones and bones, or bones and muscles, or muscles and skin, serving to prevent friction at points of stress throughout the body. In the picture, you can see the bursae are either prominently displayed (on top of the patella) or partially hidden between bone and muscle. Think of how often you move and bend your knees—I'm doing it right now, and I'm just sitting! It would be a much more painful action without the bursae there to cushion things.

Bursae come in three packages: synovial, subcutaneous, and adventitious. 



Most of the bursae in the body are synovial: thin-walled sacs interposed between bones, muscles, and tendons. The lining of a bursa contains a capillary layer of synovial fluid, which provides two lubricated surfaces that enable freedom of movement. Synovial bursae tend to be located in your joints, like your knees, feet, and shoulders.

 Muscle bursae shoulder joint subacromial bursa synovial resized 600


There are also adventitious, or accidental, bursae. These occur in soft tissue over bony prominences, usually because of repeated pressure or shearing.

An example of an adventitious bursae is a bunion, which is a deformity of the big toe. Wearing ill-fitting shoes can sometimes force the big toe inward towards the other toes. The bursa at the metatarsophalangeal joint becomes swollen, but the biggest issue is the normal part of the head of the first metatarsal bone is tilting sideways and sticks out at its top. This creates a large bump or prominence.

 Muscle metatarsophalangeal bursa hallux big toe joint metatarsal resized 600

Subcutaneous bursae lie between the skin and a bony process, like the aforementioned olecranon of the elbow.

Muscle olecranon subcutaneous bursa elbow joint resized 600  


You've probably spent enough time on this blog to know what the suffix –itis means, so you won't be surprised when I say that bursitis is the inflammation of a bursa. When the bursae become inflamed, their gliding ability is lost, which can be painful. An inflamed bursa is usually the result of trauma, overuse, or infection. Even something as simple as lifting something heavy can bring it on.

The joints of the hips, elbows, and shoulders are normally the areas affected by bursitis, but it can occur anywhere (inflammation of the bursae in the knee is known as Washmaid's Knee).



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3D Skeletal System: 5 Cool Facts about the Hip Bones

Posted by Courtney Smith on Wed, Nov 27, 2013 @ 03:37 PM

I know, I know, it's another blog post about the pelvic girdle. Well, sort of. Sometimes it's a thankless job, holding the weight of our upper half, so this post is going to be dedicated to my favorite pair of jutting wings—the hip bones!

So sit down and take a load off, and let's dive in!


1. The proper term for the hip bones is "os coxae."

Os coxae hipbones ilia ischium pubis pelvic girdle

Os coxae comes from the Latin words "os" meaning bone and "coxae" from the old Latin word for hip.


2. Each hip bone is actually made up of three bones.

It may look like one bone, but each hip bone is made up of the ilium, pubis, and ischium, which are completely fused.


3. There's a cavity in each hip bone.

Acetabulum hip socket hipbones os coxae

No, seriously! The concave cavity in the hip socket is known as the acetabulum, which is where the head of the femur articulates.


4. There are noticeable differences between the male and female hip bones.

The female hip bones are more delicate and shallow than the male's, with less sloped ilia. However, the superior aperture of the female pelvis is larger and more circular than the male's.


5. There is a giant hole between the hip bones.

Superior aperture pelvic girdle os coxae hipbones

Well, technically it's a space more than a hole. The superior aperture is the space that divides the abdominal cavity from the pelvic cavity. If you look at the pelvic area from a superior view, you will see
the superior aperture is circular and formed by the hip bones, sacrum, and pubic symphysis.


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Topics: 3D skeletal system

3D Skeletal System: 5 Awesome Ligaments

Posted by Courtney Smith on Fri, Aug 02, 2013 @ 08:49 AM

How much do you enjoy moving? A lot, I bet. While many attribute our ability to move to the muscular system, it actually goes a little deeper than that! Your skeletal system is a rigid organ (yep, it’s living tissue!) that, without your awesome ligaments, wouldn't be able to move normally!

Ligaments are fibrous swathes of connective tissue that connect bones and help prevent your joints from flapping around willy-nilly. They also help to hold organs in place.

Let’s take a look at five of the coolest ligaments in your body!


5. Linea alba

Linea alba abdomen ligament skeleton

I love the linea alba. Do you know why? Because it’s exactly what its namesake says it is—a white line. The linea alba is a thin stretch of connective tissue that runs between the xiphoid process of the sternum and the pubic symphysis of the pelvic girdle. It also acts to divide the two rectus abdominis muscles.


4. Pubocervical fascia

Pubocervical fascia pelvis uterus bladder skeleton ligaments

Stretched across the pelvic cavity is the pubocervical fascia, which connect the cervix to the pelvic walls and posteriorly blend with the perineal membrane. Think of the pubocervical fascia as a sort of hammock for the uterus and bladder.


3. Flexor retinaculum

Flexor retinaculum ligament wrist carpals bones

The flexor retinaculum and I have a complicated relationship. On the one hand (ha!), it helps to keep the flexor tendons together; on the other, it’s to blame for my increasingly rough ride through the carpal tunnel.

The flexor retinaculum is an arch of tough, fibrous tissue attached to the pisiform, hamate, trapezium, and scaphoid, and—with the carpal bones—forms a tunnel through which the flexor tendons of the hand and median nerve pass. Carpal tunnel syndrome occurs when one of the tendons becomes inflamed; since the retinaculum is so tough, there’s not enough stretch in it to accommodate the swollen tendon, so the tendon presses against the median nerve, resulting in numbness and/or pain.



2. Nuchal ligament

Nuchal ligament skull vertebrae skeleton bones

You know what’s awesome about the nuchal ligament? If you look at it laterally, it looks like a shark fin (yes, I’m one of those people who watches “Shark Week” religiously).

The nuchal ligament extends from the external occipital protuberance and median nuchal line to the spinous process of the seventh cervical vertebra. It stabilizes the head and neck, as muscles that would otherwise attach to the spinous processes of the vertebrae instead attach to the nuchal ligament.


1. All the ligaments of the skull

Skull jaw temporomandibular joint capsule ligaments

How could I pick just one ligament in the skull when all of them are so important? The ligaments of the skull comprise the ligaments that surround the temporomandibular joint, reinforcing the area where the cranium articulates with the mandible. The temporomandibular joint is a synovial joint and allows not only for flexion and extension, but also small movements of rotation and gliding.

The main “hinge” of the joint is the sphenomandibular ligament—a flat, thin band that connects the spina angularis of the sphenoid to the lingual of the mandibular foramen. The other ligaments connect the mandible to various bones of the skull.


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3D Skeletal System: 5 Cool Facts about the Femur

Posted by Courtney Smith on Mon, Jun 17, 2013 @ 11:02 AM

The femur is an awesome bone—and not just because it has a cool name. 


1. The femur is the longest bone in the body.




2. The femur is a weight-bearing bone.




3. The greater trochanter provides leverage for gluteal muscles and other muscles that rotate the thigh.

Trochanter femur long bone gluteal muscles



4. The medial femoral condyle bears more weight due to the center of gravity being medial to the knee.

Medial condyle femur bone



5. Being a long bone, the femur contains both red and yellow marrow.

Femur marrow medullary cavity cancellous bone


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3D Skeletal System: 7 Interesting Facts about the Thoracic Cage

Posted by Courtney Smith on Thu, Mar 07, 2013 @ 08:51 AM

We spend a lot of time kicking around the office, discussing anatomy and fighting about which structures are the coolest. We all know how I feel about the pelvic girdle, but the thoracic cage comes in at a close second.

The thoracic cage is an interesting structure designed to protect some of the most important organs in your body. Keep reading to find out just how the thoracic cage is structured to make you keep on keepin' on!


1. The thoracic cage is conical in shape—narrow above and broad below. This is what helps give your upper body shape.




2. Run your hands down the back of your ribs. Can you feel the shape of the cage? It is relatively flat; the anterior part of the cage is noticeably curved to accommodate organs within it.



3. If you look at the cage in the transverse inferior, you will notice it is shaped somewhat like a kidney. 



4. Its kidney-like shape is ideal for protecting the heart and lungs. Look how neatly they fit inside. 




5. The costal cartilage are fibrous tissues that allow for the expansion of the thoracic cage. When air comes into the lungs, the lungs inflate and the thoracic cage expands to accommodate them. 



6. The 12 ribs that form the cage are uniquely shaped. Most have a head (articulates with the bodies of the vertebrae), a neck (flattened section of bone), and a shaft (serves as the attachment site for several muscles).

Ribs thoracic


7. The shape of the head is ideal for articulating with the vertebrae. 


Explore the thoracic cage.

Watch the video to see the thoracic cage from all angles and explore a rib! 


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3D Skeletal System: Atlas, Axis, and the Atlanto-Axial Relationship

Posted by Courtney Smith on Thu, Dec 06, 2012 @ 08:17 AM

There are 33 vertebrae in your vertebral column. Or is it 24? Doesn't matter—both numbers are correct. You're born with 33, but the sacrum and coccyx fuse to the rest of the spine, making it 24 by the time you're an adult.

Of those 24 (not counting the sacrum and coccyx), two vertebrae are fortunate enough to have names. The atlas (C01) and axis (C02) are two of the most important vertebrae in the spine. Without them, head and neck movement would be impossible.
The atlas and axis vertebrae are the two most superior bones in the vertebral column. They are part of the seven cervical vertebrae. The atlas is the top-most bone, sitting just below the skull; it is followed by the axis. Together, they support the skull, facilitate neck movement, and protect the spinal cord. (Think of them as BFFs—you won't find one without the other.)


Unlike the other vertebrae, the atlas does not have a spinous process. Instead, it is ringlike and consists of an anterior and posterior arch, as well as two lateral masses. The transverse processes (the protrusions of bone on either side of the ring) serve as the attachment sites of muscles that assist in rotating the head. The foramina (the holes) give passage to the vertebral artery and vertebral vein.

The axis is somewhat analogous to the other cervical vertebrae in shape, but it differs slightly for two reasons: its spinous process isn't as obviously bifid, and the presence of the dens. The spinous process serves as the attachment site for many muscles of the spine, particularly those close to the skull, as well as the nuchal ligament.


The dens (above, in green), or odontoid process, is a toothlike projection of bone that rises perpendicularly from the upper surface of the body of the axis. Its purpose is very important, but I'll get to that later.

Let's talk about joints.



There are many types of vertebral joints, but the atlas and axis form the only craniovertebral joints in the body. A craniovertebral joint is exactly what it sounds like: a joint that permits movement between the vertebral column and the skull.

The ligaments in the spine support and reinforce the joints between the vertebrae. The atlas and axis in particular work with the ligaments to move the neck. The atlas and the occipital bone form the atlanto-occipital joint, which allows neck flexion. When you nod your head as if to say "yes," that is neck flexion. The atlas and axis form the atlanto-axial joint, which allows head rotation. If you shake your head as if to say "no," that is head rotation.


The atlanto-axial joint is a compound synovial joint. A synovial joint is a freely moveable joint, differing from other types of joints due to the presence of synovial fluid, which lubricates the joint. Most of the main joints (hands, feet, and other regions in the appendicular skeleton) are synovial joints.

It is also a pivot joint. A pivot joint is made by the end of one articulating bone rotating in a ring formed by another bone and its ligaments. Think of a metal washer twisting around a bolt. The dens articulates with the facet on the atlas, as well as the transverse ligament, and this articulation provides the head with approximately 50% of its movement.


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3D Skeletal System: The Maxillae with Skeleton Premium 2

Posted by Courtney Smith on Fri, Nov 09, 2012 @ 08:27 AM

The human skeletal system has over 200 bones, and those bones have over 800 bony landmarks. Bet you never guessed that your bones were so complex. Haven't you learned by now that every part of your body is ridiculously awesome?

We took those 200+ bones and 800+ landmarks and packed them all into our newest app: Skeleton Premium 2 for iPad. We’ve also included some cool new content on synovial joints, bone tissues, and skeletal system pathologies. But wait, there's more! There's also a big section of quizzes!

Pretty awesome, right? Well, guess what? I'm going to give you a sneak peek of the app (it's not published just yet!). I'm going to use just one section of the app (the bone region section) for you to learn some basic facts about the maxilla bone and its landmarks.

No need to thank me.

skeleton 3D skeleton anatomy

Skeleton Premium 2

Here is a quick preview of what is in the app:

* True 3D models of bones and ligaments in a complete skeleton that can be rotated and zoomed to study details.  

* Over 800 bony landmarks and regions illustrated in color. Additional information for each landmark includes its pronunciation and table data that lists attachments, articulations, locations, and nerve and vascular passage.

* More than 200 preset views that present individual landmarks on each bone and articulations and ligaments by skeletal regions.

* 3D moving models of synovial joints

* A gallery of animations and illustrations that show bone tissue, pathologies, and regional anatomy

* A quiz bank with over 500 questions




So, you open up the app and the first thing you see is a menu (the one in the image above). Pretend you have the app in front of you. Select Region Views, which brings up a bunch of tabs and thumbnails (below). Each tab contains preset views organized by five body regions. (You can edit these views any way you want by rotating, zooming in and out of, adding or removing structures. The views provide an easy place to start.)

 Skeleton 3D skeleton main menu


Tap the Skull tab, then choose the 21. Maxilla, Context view.

 Maxillae Bones Skull resized 600

That action launches a preset view that  shows where the maxillae are in the skull (above). Using my finger (like a pen stylus), I can drag it to rotate the model for a superior view. To get a really good one, I'd eliminate the frontal and parietal bones (below). Notice that from this angle the maxillae seem to flank the nasal cavity.


Maxilla bones maxillae superior 3D bones

How do the maxillae contribute to the nasal cavity? To figure it out I can take the model, remove all the bones that aren't part of the facial skeleton, and turn it around to get a posterior view (below, right). 

hard palate maxillae maxillaposterior maxilla maxillae

Now, isn't that a cool view? See how the maxillae help form the nasal cavity? This view also shows that a part of the maxillae form the hard palate. To get a better view of that, I can hide everything except the maxillae (and teeth) and rotate the model for an inferior view (above, left). 


Maxilla maxillae facial skeleton

To bring the original view (a.k.a. the starting point) back, I can reset the view by tapping on its name in the top left corner (21. Maxilla in Context). To get a definition, I can click the Definition button across the bottom.



While the context is interesting, what about the bone itself? By clicking on the Explore This Bone button, we can take a deep dive into the bone landmarks of the maxilla. Once you click it, a model of the maxilla in isolation appears, along with a key that designates 13 landmarks on the bone. By tapping different parts of the bone, I can see the names and locations of the various landmarks.

Maxilla Bone Anterior resized 600

To differentiate between the landmarks, I can turn on a color-coded map to make them visible and distinct. (That's what I did below. In the following four pictures I also selected the button that hides all the UI elements. I did that just to focus in on the bone for a moment.)


Maxilla maxillae anterior 3d bone

maxilla maxillae lateral view 3d bone

I can rotate the bone 360 degrees and tilt it so I can get a view from any angle. Check out the above images. I can see the maxilla from an anterior view (above, left) to lateral views (above, right and below, left), to an inferior view (below, right).


maxilla maxillae 3D bone alveolar cavities alveolar processes maxilla maxillae

Look at that last picture (above, right). See the green outline? The green designates the alveolar process, which articulates with the teeth. The cavities (shown in blue) are the alveolar canals. 

Okay, while clicking around the veritable rainbow of landmarks, say I wanted to learn some stuff about those cavities. So, I call up the landmark information and get down to business.

 Maxilla Alveolar Canals resized 600

The alveolar canals (cavities for teeth) are highlighted. These canals provide passage to the superior alveolar vessels and posterior alveolar nerves. 


Maxilla Maxillary Tuberosity resized 600

Directly above the canals is the maxillary tuberosity. It's where the pyramidal process of the palatine bone and the lateral pterygoid of the sphenoid articulate with the maxilla. It's also where the medial pterygoid muscle attaches (the muscle that draws the mandible forward).


Maxilla Bone Lateral Hard Palate resized 600

At the beginning of this post, I mentioned the hard palate. Well, here it is! It too provides passage to nerves and vasculature.



Maxilla Bone Alveolar Process Quiz resized 600


Last but not least, a visual quiz. Can you point to the alveolar process in the image above (without looking at the preceding images and text, you bunch of cheaters!)?

If you guessed the green outline around the alveolar canals, you're right! Good job.

So, what do you think? Pretty nifty, right? Leave your feedback in the comments section!


Topics: 3D skeletal system

3D Skeletal System: Bones of the Thoracic Cage

Posted by Courtney Smith on Wed, Oct 24, 2012 @ 03:17 PM

Put your hands on your chest and take a deep breath. Feel how your chest expands? That's your thoracic cage—or rib cage, as it's more commonly known—pressing up against your hands. Without the thoracic cage, some of your body's most important organs would be unprotected, and your torso would be completely without shape. Imagine walking around with your lungs somewhere near your stomach and your shoulder girdle collapsing into itself. Not a pretty thought.

The thoracic cage, a flexible framework of bones and cartilage, is conical in shape. It is narrower at the top and broadens to fit and protect some critical organs of respiration and circulation—that is, the lungs and heart. The thoracic cage gives your upper torso structure. Women have smaller cages than men; the capacity is less, and the sternum is shorter and higher.


Note the anterior view of the thoracic cage above: The front of the thoracic cage includes  seven pairs of vertebrosternal ribs (true ribs), which articulate with the sternum, an elongated flattened bone. There are also three pairs of vertebrochondral ribs (false ribs)—each false rib attaches to the cartilage of the rib directly above it.  


Take a posterior look at the thoracic cage and you’ll find another two pairs of ribs; these are the vertebral ribs (floating ribs).  Posteriorly, all 24 ribs articulate with vertebrae of the thoracic portion of the vertebral column.

Like anything else in the body, the ribs that make up the thoracic cage aren't blank curves of bone. The ribs are complex in their own right. Let's take a look!



The true ribs, false ribs, and floating ribs all have a head, neck, and shaft. All the ribs of the thoracic cage articulate with vertebrae and each has a costal groove for passage of the intercostal vessels and nerve. Looking at the 24 ribs together you might tend to think that the ribs differ only in size. But they differ in shape too. For the sake of expediency let’s look at the particular bony landmarks on the seventh vertebrosternal rib (the 7th true rib). It helps form the first section of the cage.




Shaft (orange)

The longest part of the bone; gives attachment to the intercostals, the external oblique, the iliocostalis lumborum and thoracics, levatores costarum muscles, and the serratus anterior

Tubercle (olive)

Eminence that articulates with the transverse process of T07

Neck (dark grey)

Attachment site for the anterior costotransverse ligament

Head (pink-orange)

Articulates with the bodies of T06 and T07, and acts as the attachment site for the interarticular ligament

Costal cartilage (neon green)

Cartilage that allows the ribs to move; attachment site for diaphragm, pectoralis major, rectus abdominis, and transversus thoracis

Costal groove (purple)

A groove on the inner part of the bone, through which the intercostal nerves and vessels pass



Cervical Rib

While most of us are born with 12 sets of ribs, it's not uncommon to have a normal variance or two. There is a chance, dear reader, that you may have more than the normal number of ribs.  Crazy, right? Supernumerary ribs can be a harmless variant in most cases, but in some it can cause issues.

A cervical rib is a normal variant. A cervical rib is a congenital disorder in which one extra rib arises before the first normal set of ribs (01). It is small and is often called a "neck rib" due to its location. A cervical rib is present in only 0.5% of the population and is more common in females than in males. In rarer cases, an individual can present an extra set of cervical ribs.

A cervical rib is usually asymptomatic, but in some cases it can cause thoracic outlet syndrome by compressing the brachial plexus or subclavian vessels. Symptoms include pain almost always, as well as discoloration of the hands, weakness of the hand or arm, and stiffness.


Short Rib

A short rib is not a clinically significant variant, and is thus named for when a mid-thoracic rib arch is shorter than it should be through no fault of trauma or surgery. A short rib occurs in approximately 16% of the population, and out of those instances, only 8% occur on the right side.

Funnel Chest

In contrast, pectus excavatum or funnel chest is a depression of the sternum, which causes the skin to be concave. In some cases, funnel chest is a cosmetic issue, but in others it can lead to impaired breathing, heart displacement, decreased heart density, and chest pain.


Now I want you to put your hands back on your chest and take a deep breath. Feel the 12 sets of bone expand against your fingers. If you ever get stuck on what it is your thoracic cage does, think of it as your body's police force: it shapes and protects.


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3D Skeletal System: Function of the Sphenoid

3D Skeletal System: The Pelvic Girdle


Kurihara, Y. et al (1999). The ribs: Anatomic and radiologic considerations. Manuscript submitted for publication, Department of Radiology, St Marianna University School of Medicine, Kawasaki City, Kangawa, Japan.

Freyschmidt, J., Brossman, J., Wiens, J., & Sternberg, A. (2002). Koehler/zimmer's borderlands of normal and early pathological findings in skeletal radiography. (5th ed.). Germany: Thieme.

Topics: 3D skeletal system