"Your joints are really articulate!"

Wonk wonk wonkkkk.

Articulations is just another word for a bone that connects with another bone. With articulations, the movement is inversely proportional with stability. Hence, the higher the mobility, the lower the stability and vice versa.

From descending order of mobility:
a. Glenohumeral joint (shoulder)
b. Hip joint
c. Humeroulnar joint (elbow)
d. Intervertebral joint
e. Sutures

The joints can be differentiated based on Structure or Function. Structure is based on what type of connective tissue the joint is made up of while Function is just another word for movement or degree of mobility.

Functions.

There are three types of functions (movements):
a. Synarthrosis - no movement
b. Amphiarthrosis - slight movement
c. Diarthrosis - move all you want

A good way I remember this is through the word SAD.

Structures.

There are three types of structures (what type of connective tissue):
a. Fibrous - dense regular connective tissue
b. Cartilaginous - cartilage is..... cartilage.
c. Synovial - synovial fluid, joint capsule and ligaments for stabilization

Fibrous.

a. Gomphosis - in the mandible and maxilla, synarthrosis. A good way to remember is by the word "Gom" -- it sounds just like where it is, in the gums!

b. Sutures - in the cranial skeleton, synarthrosis. If you remember from the last post, it is only with adults that the sutures are synarthrosis. They used to be the fontanelles.

c. Syndesmosis - also known as the interosseous membrane between the radius and the ulna in the middle and distally, amphiarthrosis.

Cartilaginous.

a. Synchondroses - Look at the word "chondroses", also synonymous to "chondrocytes" found in cartilage, specifically, hyaline cartilage. These are synarthrosis and are found in the epiphyseal plate of growing children and in costochondral joints of the ribs.

b. Symphyses - Guess where? In the pubic symphysis! What's interesting about them is that the body releases a hormone for the expansion of the pelvis when giving birth. Symphyses are also found in the intervertebral disc of the vertebrae and are made up of fibrocartilage as a shock absorber. They are amphiarthrosis.

Synovial.

 

 

 

Starting from the outermost layer of the synovial joint is the fibrous layer. The fibrous layer is made up of dense connective tissue layer. The inner layer is called the synovial membrane that secretes the synovial fluid filling the synovial cavity to supply nourishment and to absorb shock. The bones are capped by articular cartilages, particularly by hyaline cartilage.

 

Nerves are also present in the synovial joint to allow stimulus for pain. Minimal blood vessels are present. This is why joints takes time to heal!

 

Seen above are ligaments present in and around the synovial joint. The rope like drawings are the ligaments that connect a bone to another bone. The capsular ligament is around the joint capsule, the intracapsular joint are inside the capsule and the extracapsular joint are outside the joint capsule.

 

Types of Synovial Joints.

 

 

Movements of bones include uniaxial (one plane), biaxial (two planes) and multiaxial (more than two planes).

From the lowest mobility to the highest mobility, silly as it sounds, I like to remember the sentence "Peter Pan Hugged Some Cute Bear" to remember the hierarchy.

http://images.mocpages.com/user_images/48287/1366754888m_SPLASH.jpg


REMEMBER! "Peter Pan Hugged Some Cute Bear"

But remember, you gotta remember what the acronym stands for or you'll fail Anatomy. Scary!

Ready? Let's get to the meat!

a. Planar (gliding) - is uniaxial, the least movable of all, are flat in shape and can only move from side to side. Examples include intercarpal joints, intertarsal joints, acromioclavicular joint and vertebrocostal joints.

b. Pivot - is also uniaxial, consists of a peg and a hole with ligament and a bone. Moves in a transverse plane. Some examples are the atlas, axis and proximal radioulnar joint. How I remember this is by picturing a pivotal handle on a radio.

engineersgarage.com

c. Hinge - is also uniaxial, consist of a convex and a concave shape. Moves in a sagittal plane. An example is the humero-ulnar joint also known as the elbow.

d. Saddle - is biaxial, consists of a convex and a concave shape. Movements are in frontal and oblique planes. How I remember this is I picture a horse's oblique muscles. Saddle and horses and oblique planes.... 

http://classconnection.s3.amazonaws.com/583/flashcards/651583/jpg/abdominalobliques1328643963804.jpg

 

An example of a Saddle joint would be the carpometacarpal joint and the trapeziometacarpal, or a fancy way of saying thumb. If you ever want to impress somebody with a fancy word for saying the thumb joint.....

e. Condyle - is also biaxial, consists of a concave and a convex, oval/egg shaped, moves in frontal and sagittal planes. A great example of the condyle is the metacarpophalangeal joint.

f. Bear.... or oops... the Ball and Socket (don't do that on the exam ok) -  is triaxial, is the most movable of all, consists of a ball shape and a cup like shaped bone. The glenohumeral or the shoulder joint is a great example of the Ball and Socket joint.

Now on to the injuries. Ouch! Most injuries are seen in the shoulder and knee joint because they are the most mobile joints. Unfortunately, they sacrifice stability in exchange for their mobility. It's like a give and take relationship.

Dislocation is what it sounds like, the bones are completely knocked out of alignment.
Subluxation is partial dislocation. Subluxation is a term mostly used for the vertebrae.

Sprains are caused by stretching or tearing of the ligaments. The first degree is by stretching only. The second degree is partial stretching and partial tearing. The third degree is by tearing and only tearing.

Sprains take a while to heal because they are not vascularized like bones are.

These sprains can be classified as either a high ankle sprain or a low ankle sprain.

The high ankle sprain is the result of a divorce between the married tibia and fibula. They got divorced because they were always high, it sprained their relationship... wonk wonk wonk.  Man, I am such a dork. This is also known as the syndesmotic sprain, usually a result of overinversion which causes bruising and swelling.

The low ankle sprain, sprains the talocrural (ankle) joint and also causes bruising and swelling.

Arthritis.

This is my simple mathematical equation that I invented.

Arthritis = inflammation

Pretty simple, right?

There are several types you have to remember --  osteoarthritis, rheumatoid arthritis and gout.

Osteoarthritis is the cause of wear and tear of the articulating cartilage.

Rheumatoid arthritis is an autoimmune disease where the body is attacking its own joint tissues.

Gout  is seen in patients with kidney issues as a result of the deposition of uric acid where the body is unable to get rid of urea. These build up crystals that causes rubbing and tearing.

Now it's just pure memorization time

Sagittal plane - flexion, extension, hyperextension, dorsiflexion and plantarflexion

Frontal plane - Abduction, Adduction, Lateral flexion

Transverse plane - Medial and lateral rotation, rotation right and left, supination and pronation (shout out to runners/joggers out there...  I used to jog a lot until I gained 1000 pounds. That was called a hyperbole)

Special movements (aplanar or multiplanar) - inversion, eversion, protraction, retraction, elevation, depression and circumduction.

a. Shoulder (glenohumeral) - ball and socket; flexion, extension, hyperextension, abduction, adduction, medial and lateral rotation and circumduction

b. Elbow (humeroulnar) - hinge; Easy! Just plain ol' flexion and extension!

c. Wrist (radiocarpal) -saddle; flexion, extension, abduction, adduction and circumduction.

d. Knuckles (metacarpophalangeal) - condylar; same as the wrist.

e. Finger and toes (interphalangeal) - hinge; flexion and extension

f. Hip - Lateral flexion, flexion, extension, abduction, adduction, medial rotation, lateral rotation and circumduction

g. Knee - hinge; flexion, extension, medial and lateral rotation

h. Ankle (talocrural) - hinge; dorsiflexion and plantarflexion

i. Intertarsal (talonavicular) - Inversion and eversion

j. Atlanto occipital - condyle; flexion and extension

k. Atlanto axial - head rotation


The Shoulder.

These are ligaments you have to remember. Look at my sucky illustration below.

The Knee.

Again with the sucky illustrations!

Have a great day,

M

A summary (sort of) of the axial and appendicular skeleton

The axial skeleton consists of the skull, vertebral column and the thoracic cage while the appendicular skeleton consists of the pelvic girdle, the pectoral girdle and the upper and lower extremities.

Starting with the...

The Axial skeleton.

The axial skeleton consists of the skull, which is divided into either a cranial bone or a facial bone. The cranial bone is directly connected to the brain while the facial bone do not make direct contact with the brain.

The Hyoid Bone.

If I were a bone, I would probably be the hyoid bone, because it is the only bone that do not directly interact with other bones! It's kind of anti social, if you ask me.

Some things to remember about the hyoid bone is that it is underneath the mandible or the jaw bone and it is attached to the tongue and the muscles of the larynx for swallowing.

The Auditory Ossicles.

These are so interesting. They are so tiny, I wonder how they can transmit such great sounds to our brain so precisely.

A good way to remember the three muscles is through the word MIST, from lateral to medial position:

M- Malleus
I- Incus
ST - Stapes

The Vertebral Column.

For some reasons, I am having a hard time remembering the parts, specifically the differences and similarities between the different vertebrae.

The vertebrae can either be atypical or typical. The atypical vertebrae consists of the C1 (Atlas), C2 (Axis), Sacrum and Coccyx. What's interesting about the sacrum and the coccyx is that the Sacrum is a result of a fusion from 5 vertebrae while the Coccyx is a combination of 4 vertebrae. The rest is typical vertebrae (C3 - C7, T1 - T12, L1- L5). The curvatures of the vertebrae come from the posterior curves of the thoracic and the sacral region.

Some diseased vertebrae that I should know are Kyphosis, Lordosis and Scoliosis.





thepartyworks.com


 

Kyphosis is also known as the "hunchback" and is a  problem in the thoracic region as a result of the compression of fractures.

Lordosis, also known as the "swayback" is a problem in the lumbar region, commonly seen in pregnant women or people with "santa bellies"

Scoliosis or the lateral movement of the vertebral column, seen in the thoracic region as well. This is commonly seen in women.






Now on to the specific parts of the vertebral column (GASPPPPP!)

Let's start with the atypical.

The C1 also known as the Atlas has NO BODY, however it has superior articulating surfaces that, well... articulate with the occipital condyles of the skull. These also have transverse processes as well as transverse foramen.

The C2 also known as the Axis does not have a  body, but has a Dens or an Odontoid process, a superior articular facet, transverse processes, transverse foramen, a lamina, a pedicle and a bifed spinous process.

Now on to the typical vertebrae.

The C3 to C7 cervical vertebrae are small, but what sets them apart are the transverse foramen on each side that houses the vertebral arteries that supply blood to the brain. They also have bifed spinous process and a body.

The T1 to T12 thoracic vertebrae are medium in size. They have all the features - the body, the pointy spinous process, the superior articular facet (smooth surface) , a superior articular process (some sort of protrusion), transverse processes with costal facets and costal demifacets on the inferior side of the body. They also have a vertebral arch consisting of the lamina (beside the transverse process) and the pedicle (with the superior articular process). The vertebral foramen or canal houses the spinal column.

Lastly, the Lumbar vertebrae. The Lumbar vertebrae are large in size and has almost the same features as the thoracic vertebrae except that they have a very blunt spinous process and no costal demifacets.

Moving on to the thoracic cage.

The thoracic cage are fully developed by the age of 40. The three bones include the Manubrium, the body and the Xiphoid process.

The thoracic cage has true ribs (1 to 7), the false ribs (8-12) and the floating ribs (11-12) that are not connected to the costal cartilages.

The ribs are articulated with the vertebrae via the thoracic vertebrae's transverse costal facet and costal demifacets.

The Appendicular Skeleton.

 

 

The appendicular skeleton consists of the pectoral girdle, the upper extremity, the pelvic girdle and the lower extremities.

 

 

The Pectoral Girdle.

The pectoral girdle consists of two bones, the clavicle and the scapula. The clavicle has two ends, one end connecting to the sternum, called the sternal end and the acromial end, connecting to the acromion of the scapula. A personal aside, I think that the scapula is beautiful. It is so "edgy" and "spiney", but really versatile. The only downside is that it sacrifices stability for mobility,  so injuries are common in this part of the skeleton!

The Radius and Ulna.

The Radius and the Ulna are connected by the interosseous membrane made out of dense regular connective tissue.

 

Know all the parts.

 

The hand consists of carpals, metacarpals and phalanges (such a funny sounding word)

The carpals starting from the proximal  row from the radius side (lateral side) is the scaphoid, directly connected to the radius, then the lunate, directly connected to the ulna, the triquetrum on the most medial side, the pisiform which looks like a hook coming out of the triquetrum, the hamate, the capitate (right in the middle distal row), the trapezoid and the trapezium underneath the scaphoid.

 

The metacarpals are numbered from I - V. I as the pollex or the thumb and the pinky as roman numeral number V.

 

The rules for naming the hand bones: the bone number, metacarpal and left or right.

 

The rules for naming the phalanges: the bone number, proximal/middle/distal, phalange and left or right.

 

The Humerus.

 

The funny bone has a head, a greater tubercle, a lesser tubercle, a deltoid tuberosity on the lateral side, a coronoid fossa on the anterior side, a trochlea, epicondyles and an olecranon fossa on the posterior side.

 

 

 

The Pelvis or Os Coxae.

 

The Pelvis is formed by the age of 13 - 15, fusing the ilium, ischium and the pubis. See illustration above. My favorite drawing, by the way. lol

 

The Femur.

 The femur has a head, a greater and lesser trochanter, epicondyles on the sides, condyles and a linea aspera on the posterior side. Femur is the strongest, heaviest bone.

The Tibia and the Fibula.

These are fairly simple. The Tibia has a lateral and a medial condyle. A tibial tuberosity and a medial malleoli. The Tibia is the thickest skeletal bone. The Fibula has a head and a lateral malleoli.

Metatarsal.

The Metatarsals  consists of the medial, intermediate and lateral cuneiform, a cuboid, a talus and a calcaneus.

The Skull.

The fetal skull has a frontal bone, a parietal bone, an occipital bone, a temporal and a sphenoid bone just like an adult's skull. What sets them apart are their fontanelles. The fetal skull has an anterior fontanelle, a sphenoidal fontanelle, a mastoid fontanelle and a posterior fontanelle. They are very cool because they allow flexibility during birth and through the growth of a baby's brain.

I hope you enjoyed some of my sucky illustrations!

Have a great day,
M