Download File

Chapter 5: The Skeletal and Articular
Systems
Using Anatomical Terminology

The standard orientation of the human body is known as the anatomical position.





The anatomical position is :
Standing upward and straight – with his or her head, eyes, and toes pointing forward
Looking forward
Arms at your side and feet are together.
Hands facing forward – forearms are supinated.

The key relationships in the anatomical position are:

Anterior and Posterior:

Superior and Inferior:

Medial and Lateral:

Proximal and Distal:

Superficial and Deep:
Anterior refers to the front surfaces of the body (ie: your chest is
anterior to your back) and posterior refers to the back surfaces (ie: your heart is posterior to your
sternum).
Superior refers to upwards surfaces (ie: your shoulder is superior to your
fingers) and inferior refers to downward surfaces (ie: your knees are inferior to your hips).
Medial means toward the midline or towards the median plane (ie: your
sternum is medial to your shoulder) and lateral means away from the midline or away from the median
plane (ie: your baby toe is lateral to your big toe).
Proximal means towards the point of attachment of the limb to the body
(ie: your thigh is proximal to your hip joint) and distal means farther away from the point of attachment
(ie: your toes are at the distal end of your foot).
Superficial means on, or close to, the surface of the body (ie: your skin is
superficial to your blood) and deep means farther away from the surface of the body (ie: your pancreas
is deep in relation to your bones).
1
Anatomical Planes

The anatomical position can be further standardized by dividing the body into three anatomical planes or sections.

An anatomical plane is the anatomical position in which an imaginary flat surface is passing through the
body or organs.
Anatomical planes relate to positions in space and they are at right angles to one another.
Anatomical planes can be used to describe directional cuts (or sections) through parts of the body. For example, a
frontal section of the heart exposes various parts of the heart from the front, a sagittal section would expose the
heart from the side, and a transverse section would expose the heart so that it could be viewed from the top or
from the bottom.
The three anatomical planes are:




Frontal Plane:

Transverse Plane:
The frontal (coronal) plane is vertical and goes through the body from one side to
the other, dividing the body into a front and back section.
The transverse (horizontal) plane is horizontal and divides the body into an
upper and lower section.

Sagittal Plane:
The sagittal (median) plane is vertical and extends from the front of the body to the
back, and divides the body into a left and right section.
Anatomical Axes


The human body can also be divided into anatomical axes – a series of imaginary lines (points of rotation)
that pass through a joint or the body to describe a movement.
There are three anatomical axes:
2

Horizontal axis:

Longitudinal axis:

Antero-posterior axis:
The horizontal axis extends from one side of the body to the other. It goes
through our two hips and allows movement in a rotation around our hips (ie: summersaults). It runs
perpendicular to the sagittal plane.
The longitudinal axis (also known as the polar axis) is vertical and runs from
head to toe. It allows movement around the centre of our body (ie: spinning in a circle). It runs
perpendicular to the transverse plane.
The antero-posterior axis extends from the front of the body to the back
(as if it is going through our belly button and out our back). It allows movement outward from our
median (ie: jumping jacks). It runs perpendicular to the frontal axis.
Describing Movement at Joints


Our bones are connected at areas called joints, which are held together by various connective tissues, including
ligaments and muscles.
Starting from the anatomical position, the following terms are used to describe the movement at joints.

Flexion and Extension:



Abduction and Adduction:



Abduction is when you move a body segment to the side and away from your body. For example,
when you lift your arm out to the side of your body (as in a jumping jack).
Adduction is when you move a body segment towards your body. For example, when you kick a
soccer ball across your body.
Supination and Pronation:



Flexion is the action of bending at a joint such that the joint angle decreases. For example,
flexion occurs when you bend your elbow to bring your palm to your shoulder.
Extension is the action of increasing your joint angle. For example, lowering your palm back
down to your anatomical position.
Supination is rotating the wrist so that the palm of your hand is facing upward. For example,
when you catch a baseball.
Pronation is rotating your wrist so that the palm of your hand is facing downward. For example,
when your dribble a basketball.
Plantar Flexion and Dorsiflexion:


Plantar flexion is specific to the ankle joint. It is when you point your toes. For example,
standing on your toes.
Dorsiflexion is when you bend your ankle and bring your toes upward. For example, each time
you take a step.
3

Inversion and Eversion:



External Rotation and Internal Rotation:




Elevation refers to movement in a superior (upwards) direction. For example, when you lift your
shoulders up while taking a breath.
Depression refers to movement in an inferior (downwards) direction. For example, when you
slouch your shoulder.
Protraction and Retraction:



Circumduction is a combination of flexion, extension, abduction and adduction all wrapped into
one movement. For example, in softball when the pitcher throws the ball in a “windmill” action.
Elevation and Depression:


External rotation results when you twist or turn a body part outward from the midline. For
example, when you rotate your foot and toes outward.
Internal rotation results when you twist or turn a body part inward towards the midline. For
example, when your rotate your foot and toes inward.
Circumduction:


Inversion is associated with the ankle joint and is a result of standing on the outer edge of your
foot.
Eversion is when your stand on the inner edge of your foot.
Protraction is moving in an anterior (forward) direction. For example, sticking out your chin.
Retraction is moving in a posterior (backward) direction. For example, squeezing your shoulder
blades together.
Opposition and Reposition:


Opposition occurs when the thumb comes into contact with one of the other fingers.
Reposition is when the thumb is returned back to its anatomical position.
4
The Human Skeleton







The adult human skeleton is made up of 206 bones and on average, accounts for about 14% of total body
weight.
Humans start off life with more than 300 bones at birth, but over time, several of these bones fuse as growth takes
place.
The bones of the human skeleton come in many different sizes – the longest is the femur (thigh bone) and the
smallest is the tiny stirrup bone found inside the ear.
Many parts of the body are made up of several bones joined together – each hand has 27 bones, and the pelvic
girdle consists of three paired bones (the ilium, ischium, and pubis).
Among humans, there are slight differences between the human skeleton of males versus females. For instance,
males tend to have slightly thicker bones as well as longer legs and arms; females tend to have a wider pelvis and
a larger space within the pelvis to facilitate the birth process.
Compared to other body systems, the skeletal system is extremely hard and durable. As bones are primarily
composed of calcium, people with diets low in this mineral may find their bones becoming increasingly brittle
and breakable.
Bones are able to heal themselves – that is why when you break a bone and wear a cast for several weeks, your
bone will be healed.
The Role of the Skeleton



The skeleton supports the body and works in conjunction with the muscles to cause movement.
The skeleton also protects vital organs – for example, the skull protects the brain, the ribcage protects the lungs
and heart, and the vertebral column protects the spinal cord.
The main functions of the skeletal system are:
5
Structural support for soft tissue, including muscle and internal organs
Structural
Support
Protection
Growth centre
for cells
Reservoir of
minerals
Movement
Protective cage for more delicate parts of the body (ie: the skull protects the brain)
Red blood cells and platelets are formed in the marrow of our bones
A reservoir that the body can call upon in order to regulate the level of calcium and
phosphorus in the body.
Muscles attach to bones by tendons. Muscles contract and move bones to facilitate
movement.
Five Types of Bones

The following are the 5 types of bones that are classified according to their shape:




Long Bones: Long bones are found in the arms and legs. For example, the femur.
Flat Bones: Flat bones are flat and thin. For example, the bones of the skull.
Irregular Bones: Irregular bones are odd-looking bones. For example, a vertebrae.
Sesamoid Bones: Sesamoid bones are unusual bones in that they are small, flat bones that are
wrapped within tendons that move over bony surfaces. For example, the patella.

Short bones:
Short bones are small bones that are commonly found in the wrist or ankle. For
example, the carpal bone.
The Structure of the Skeleton

The skeletal system is generally divided into two main parts: the axial skeleton and the appendicular skeleton.
 The Axial Skeleton

The axial skeleton is comprised of 80 bones
6




The axial skeleton is comprised mainly of the vertebral column (the spine), much of the skull, and
the rib cage.
The axial skeleton is mainly involved in protection of major organs (ie: the skull protects the brain, the
ribcage protects the heart and lungs, and the vertebral column protects our nerves).
The muscles of the axial skeleton include those of the face, tongue, and neck, muscles used for chewing
(mastication) and drinking, as well as the muscles around the vertebrae of the spine.
Most of the body’s core muscles originate from the axial skeleton, since it is medially located with
respect to the appendicular skeleton. These muscles are referred to as “core muscles” because they
provide the body with stability and support. Examples include the rectus and transversus abdominis,
and the erector spinae group.
 The Appendicular Skeleton

The appendicular skeleton is comprised of 126 bones



The appendicular skeleton includes moveable limbs and the supporting structures (girdles).
The appendicular skeleton plays a key role in allowing us to move about.
The upper limbs are attached to the pectoral girdle (the shoulder girdle) and the lower limbs are attached
to the pelvic girdle (the hip girdle).
The pectoral girdle is comprised of two scapulae (shoulder blades), and two clavicles (collar bones).
The humerus attaches at the glenoid cavity (the shoulder socket).
The pelvic girdle is comprised of two sturdy hip bones. The two hip bones and the sacrum form the
complete ring of the pelvis. On the outer side, where the fused bones meet, there is a socket (the
acetabulum cavity) into which the head of the femur fits.
The appendicular skeleton can be divided into six major regions:






Pectoral girdle (4 bones) – the left and right clavicles and scapulae.
Arms and forearms (6 bones) – left and right humerus, ulna, and radius
Hands (54 bones) – left and right carpals, metacarpals, proximal phalanges, intermediate
phalanges, and distal phalanges.



Pelvis (2 bones) – left and right hip bones
Thighs and legs (8 bones) – left and right femur, patella, tibia, and fibula
Feet and ankles (52 bones) – left and right tarsals, metatarsals, proximal phalanges,
intermediate phalanges, and distal phalanges.

All the bones in the human skeleton have features known as landmarks.

A landmark is a ridge, bump, groove, depression, or prominence on the surface that serves as a guide to the
location of other body structures.
Bone landmarks allow for the passage of blood vessels and nerves, for joints between bones, and for the
attachment of ligaments, muscles and tendons.

The Anatomy of a Long Bone

Cartilage: is located on both ends of a long bone and is referred to as articular or articulating cartilage.
It
allows for smooth movement (articulation) within joints while protecting the ends of bones. Cartilage does not
have a blood supply or nerve endings.
7

Periosteum:

Medullary cavity:
Is found inside the shaft of the bone and is filled with red and yellow bone marrow. Red
marrow is where blood-cell formation (hematopoiesis) occurs. Yellow marrow is made up mostly of adipose cells
(fat) and connective tissue that has no role in blood-cell formation.

Compact Bone: Is the dense part of the bone, and is responsible for structural integrity. Bone is thickest
along the diaphysis (shaft) of the bone.
Cancellous bone: Is also known as the spongy bone, and is filled with marrow in its small cavity-like

Is the outer connective tissue that covers the entire length of the bone. It is where ligaments and
tendons unit to connect bones to muscle, or bone to other bone.
spaces. Compact and cancellous bone will strengthen with exercise, specifically exercise that increases the loads
to which the bones are accustomed.

Epiphysis:

Epiphyseal plates:

Cortex:

Trabeculae:
Is located at the ends of long bones. The outer surface of the epiphysis is made up of compact
bone, and the part that articulates with another bone is covered with cartilage.
Is also known as a growth plate. It occurs at various locations at the epiphysis of a long
bone. If an x-ray shows dark lines, you know that an individual’s growth plates have yet to fuse, and they have
more growing to do.
The exterior layer of bone that is dense and smooth. The interior core consists of networks of fibres
(trabeculae) that mesh with blood vessels and the bone marrow.
Consists of bony fibres arranged in a strut-like system running throughout the cancellous tissue.
Bone Injuries and Bone Disease



Problems of the skeletal system can be associated with many factors, including nutrition, infection, and physical
accidents.
Young people generally have weaker bones since calcification is still incomplete.
Older people can suffer from bone weakness because of the loss of calcium associated with aging.
Fractures

Fractures are bone “breaks” and are normally divided into three types according to the severity of the break.
8

A simple fracture occurs when there is no separation of the bone into parts, but a break or crack is
detectable. This break is also referred to as a “hairline fracture” or a “greenstick fracture”.

A compound fracture occurs when the bone breaks into separate pieces (sometimes referred to as a
transverse fracture). This would be the result of a major blow.

A comminuted fracture occurs when the broken ends of the bone have been shattered into many pieces, as
might occur in the case of a major automobile accident.
The symptoms of a bone fracture are sharp pain and tenderness, swelling, discolouration of the skin, and a grating
or grinding movement.
In serious cases, there will be an inability to use the body part supported by the bone.
Serious problems arise with breaks that occur at or near joints, since these kinds of fractures will impede motion
unless they are properly treated.



Stress Fractures and Shin Splints






Stress fractures are the most common injury due to sports.
When muscles become too fatigued to absorb the shock placed on them – for example, through the continual
pounding of long-distance running – the overstressed muscle transfers the impact to the bone. This causes the
bone to develop a tiny crack, or stress fracture.
Stress fractures can also occur by a rapid increase in activity when an athlete switches to a new surface for
training or poor footwear with improper cushioning.
If you suffer from stress fractures, it is recommended that you take 6-8 weeks of rest to allow time to recover.
Shin splints are also a result of overuse without adequate time for recovery. The term “shin splints” refers to a
painful condition occurring on the medial or lateral side of the tibia (shin bone), on its shaft.
The risk factors for shin splints are similar to that of stress fractures. If shin splints are left untreated, they can
develop into serious problems such as stress fractures.
The Effects of Aging on the Skeletal System



By far, the most widespread serious medical problem associated with bones is osteoporosis (or porous bone),
a degenerative condition that involves low bone mass as well as a deterioration of the bone tissue.
Osteoporosis leads to bone fragility and therefore, an increased susceptibility to bone fractures, especially of the
hip, spine, and wrist.
Osteoporosis is sometimes called the “silent disease” because people may not know that they have it until their
bones become so weak that a sudden bump or fall causes or a vertebra to collapse.
9


Women lose up to 20% of their bone mass in the five to seven years following menopause, making them more
susceptible to osteoporosis.
Building strong bones during childhood and adolescence is the best defense against developing osteoporosis later
in life. There are 4 recommended steps that will help prevent osteoporosis:
 A balanced diet rich in calcium and vitamin D
 Weight-bearing exercise
 A healthy lifestyle (no smoking or excessive alcohol)
 Bone density testing and medication, when appropriate.
Bones of the Skeletal System
Bones of the Skull
Bones of the Vertebral Column
10
Bones of the Thoracic cage, anterior and posterior views
Bones of the Scapula – anterior view, posterior view, and lateral view
11
Bones of the Humerus, anterior and posterior views
Bones of the Left Ulna and Radius, Anterior View
Bones of the Left Hand, anterior view
12
Bones of the Pelvis, anterior and posterior view
Bones of the Right femur, anterior and posterior views
13
Bones of the Right fibula and tibia, anterior and superior views
Bones of the Foot
14
The Different Types of Human Joints



Joints are the points at which bones connect.
Joints are very important because they play a critical role in human movement.
They are also points of great stress and can be a common source of injury.

The articular system is a term that refers to the joints and the surrounding tissues that make connections and
therefore movement, possible.
The Structural Classification of Joints

Joints are classified according to their structure (what they are made up of) or their function (the type and

extent of movement they permit).
The structural classification recognizes three main types of joints:

Fibrous Joints:

Cartilaginous Joints:

Synovial Joints:
Are bound tightly together by connective tissue and allow no movement. These
are the joints locking bones of the skull, known as sutures. After birth, all suture joints become
immobile.
The body of one bone connects to the body of another by means of
cartilage, and slight movement is possible. The intervertebral “disks” of the spinal column (of which
there are 23) are examples of cartilaginous joints. These have a hard elastic outer ring with a soft core,
permitting some movement while at the same time providing protection against severe jolts, such as
landing hard on one’s feet.
This type of joint allows for the most movement. Examples of synovial joints are
the shoulder, knee, and ankle.
15
Types of Synovial Joints


Joints allow the bones coming together to form the joint to move relative to one another in various ways and to
various extents.
There are 6 types of synovial joints:

Ball-and-socket Joints:

Gliding Joints:

Hinge Joints:

Pivot Joints:

Saddle Joints:

Ellipsoid Joints:
It is the most maneuverable of joints, allowing for forward movement,
backward movement, and circular movement. With this type of synovial joint, the “ball” of one bone
fits into the “socket” of another, allowing movement around three axes. Examples include: the shoulder
joint and the hip joint.
This joint connects flat or slightly curved bone surfaces that glide against one
another. Examples include: the joints in the foot and the hand.
They have a convex portion of one bone fitting into a concave portion of another
bone. They allow movement in one plane – and allow for only flexion and extension. Examples
include: the bones of the fingers, and between the ulna and the humerus.
This type of joint allows for rotation in one plane – a rounded point of one bone fits
into a groove of another. An example is: the atlanto-axial articular joint between the first two vertebrae
in the neck which allows the rotation of the neck.
It allows movement in two planes: flexion-extension and abduction-adduction, but
do not allow for rotation. An example is: the thumb.
It allows movement in two planes: flexion-extension and rotation. An example
is: the wrist.
16
Characteristics of Synovial Joints

Synovial joints permit movement between two or more bones and can be distinguished by the following
characteristics:

Articular cartilage:

Joint capsule:

Joint cavity:

Bursae:

Intrinsic ligaments:
Is located on the ends of bones that come in contact with one another. This
hyaline cartilage protects the ends of the bone and allows for a smooth contact surface for the bone to
move about.
Is a fibrous structure that consists of the synovial membrane and fibrous capsule.
The synovial membrane allows certain nutrients to pass through while the fibrous capsule keeps
synovial fluid from leaking.
Is located between the two bony articulating surfaces. It’s filled with synovial fluid,
which acts as a lubricant for the joint. This lubricant is essential in reducing friction and providing
nutrients for the articulating cartilage.
Are small, flattened fluid sacs found at the friction points between tendons, ligaments, and
bone (bursa is the singular).
Are thick bands of fibrous connective tissue that help thicken and reinforce
the joint capsule.

Extrinsic ligaments:
They are separate from the joint capsule and help to reinforce the joint by
attaching the bones together.
Joint Related Injuries
Wear and Tear Injuries

Continuous, heavy use of the joints over many years can result in wear and tear on the articular cartilage at the
end of bones, leading to the erosion of the surfaces of bones at the articulations where bones come together. This
process is known as osteoarthritis. This results in joint pain and stiffness and consequently restricted
mobility.
 Osteoarthritis commonly occurs in the larger weight-bearing synovial joints, such as the hips or knees,
but it can also affect the hands, the feet, and even the spine.
17



Osteoarthritis is a degenerative disease and is irreversible. It results in the decreased effectiveness of
articular cartilage both as a shock absorber and lubricated surface.
Treatment of osteoarthritis involves pain medication and often joint replacement in the case of the hips
and knees.
Another common condition resulting from wear and tear on the joints is bursitis. Bursitis is characterized by
inflammation of the small fluid sacs (bursae) found at the friction points between tendons, ligaments, and bones.
Cartilage Damage



Cartilage is connective tissue found at the ends of bones and free-moving joints.
Cartilage is “avascular”
meaning that the nutritional needs of cartilage are not met through blood.
Cartilage damage or injuries (known as “torn cartilage”) in the knee is common among football and basketball
players and athletes in many other sports in which vigorous lateral movement and contact is common.
Arthroscopy is a surgical procedure in which a few small incisions are made so that a small fibre optic camera can
assess the extent of the damage.
Sprains


Ligaments attach one or more bones together and are significantly less rigid than bones. When ligaments reach
their threshold, they will stretch minimally but will usually tear.
Sprains occur when a ligament is overstretched.

A first-degree sprain can be treated easily since only a few ligament fibres are stretched. There
may be minimal swelling and some pain. For example, an individual “twists” his/her ankle and cannot
walk on the injured foot – but after resting, can put some weight on that foot. After a few days, the
individual can put full weight on the injured foot.

A second-degree sprain is the result of partially tearing ligament fibres which may result in
bruising and will require more attention. The damage is more widespread and the swelling and the pain
are more considerable. For example, an individual “twists” his/her ankle and cannot put any weight on
the injured foot – after resting, they still cannot put any weight (or minimal weight) on the injured foot.
They will require crutches for a few weeks before being able to put weigh on the injured foot again.


A third-degree sprain usually means that the entire ligament is completely (or almost
completely) torn. Surgery is usually required to reattach the ligament to the bone, and it will take
several months to return to normal activity. For example, a basketball player jumps and lands on the
side of his foot and feels immediate pain and a popping sensation. He will be in a cast and using
crutches for several weeks and will require physical therapy before he can resume regular activities in
about 3-4 months.
A strain occurs when muscles and tendons are overstretched and tear. Since muscles are vascular (meaning that
they have a good blood supply in order to receive nutrients) they heal faster and more effectively than a sprain.
Dislocations and Separations


A dislocation occurs when a bone is displaced from its joint.
Dislocations are often caused by collisions or falls, and are common in finger and shoulder joints. For example, a
shoulder dislocation occurs when the humerus “pops out” of the glenoid fossa, resulting in a tear to the ligament
and joint capsule.
18









The most common dislocation occurs at the finger joint.
A dislocated joint usually can be successfully put back into its normal position by a trained professional.
The following are signs of a dislocation injury:
 Significant pain and an inability to move the appendage from its current position, particularly where the
appendage is moved away from your body.
 Numbness or no feeling in the appendage
 An unusually square appearance of the joint area and/or a visibly noticeable lack of bone in the injured
joint area.
A separation is not the same as a dislocation.
A separation does not directly affect the joint itself, but rather the connecting tissue.
A shoulder separation is the separation or disruption of the ligaments attaching your collarbone (clavicle) and
shoulder blade (scapula). When these ligaments are torn, as a result of a collision or an awkward fall, the bones
may separate.
Separations are classified from grades I – VI according to the severity and the position of the injured bones.
The following symptoms are common at each stage:
 Pain at the end of the bone or over the joint itself.
 Swelling and an obvious limp where the joint has been disrupted
 Pain on moving, as when trying to raise the arms above shoulder height.
Dislocations and separations are very serious and need to be attended to by a medical professional.
The Shoulder Joint





The shoulder, or gleno-humeral joint, is a very intricate joint that, for the most part, is unstable.
It is this instability that gives the shoulder joint such versatility and permits us to perform all sorts of movements,
including abduction, adduction, flexion, extension, elevation, depression, circumduction, protraction, retraction,
and medial and lateral rotation.
This synovial ball-and-socket joint is made up of three bones: the scapula, the humerus, and indirectly with the
clavicle. The humeral head articulates within the glenoid fossa of the scapula, and it is held in place by the
ligaments of the shoulder. The long tendon of the biceps brachii also helps to support the shoulder anteriorly.
Athletes involved in sports that involve overhead actions such as throwing, swimming, hitting, and lifting, are
susceptible to shoulder injuries as a result of overuse or strain.
Some of the most common shoulder joint injuries include:

Biceps tendinitis:

Shoulder separation:

Shoulder dislocation:
It is an overuse injury and happens when adequate rest is not given to the biceps
brachii muscle when it has been worked or overloaded. Symptoms include: pain on the proximal end
(top end) of the biceps, making flexion of the shoulder and elbow painful.
It is the tearing of the acromioclavicular ligament, which holds together the
acromioclavicular joint (AC joint, the union of the clavicle and the acromion). Injuries of this nature are
a result of falls directly on the shoulder, usually as result of contract from another player or a tumble on
the shoulder. Surgery may be required if the tear is a 3rd degree.
It occurs when the humerus “pops out” of the glenoid fossa. It is usually
the result of a fall resulting in a tear to the glenohumeral ligaments and joint capsule. There are
numerous ital. nerves known as the brachial plexus, and blood vessels that supply the shoulder and arm.
Attempts to put the shoulder back in should only be performed by qualified personnel in a medical
environment. Surgery may be required to repair the shoulder in 3rd degree dislocations.
19

Rotator cuff tears:
It involves one or all four muscles that make up the rotator cuff:
supraspinatus, infraspinatus, teres minor, and subscapularis. They all share a common insertion on the
greater tubercle of the humerus. Athletes who have sustained a rotator cuff injury find it hard to abduct
and laterally or medially rotate the shoulder. Physiotherapy exercises can help to strengthen, stabilize,
and improve flexibility of the rotator cuff. Severe injuries will require surgery.
The Knee Joint



The knee joint is made up of the articulation of the femur and the tibia.
The knee joint has been classified as a modified hinge joint; however, the knee has the ability to slightly rotate the
leg medially and laterally, therefore classifying it, more specifically, as a modified ellipsoid joint.
The distal end of the femur is covered with articular cartilage that rests on the proximal end of the tibia, which has
two thick fibrocartilage articular disks known as menisci (meniscus is the singular). They sit on the tibial condyles
that are located on either side of the intercondylar eminence.
The ligaments cross each other and are called the cruciate ligaments – the anterior cruciate ligament (The ACL)
helps stop anterior movement of the tibia with respect to the femur; the posterior cruciate ligament (The PCL)
helps stop posterior movement of the tibia in respect to the femur.
The knee is also held together by the fibrous capsule and by collateral ligaments – the medial collateral ligament
(The MCL) and the lateral collateral ligament (The LCL) – together, these two ligaments provide medal and
lateral stability to the knee.
The quadriceps muscles stabilize the anterior side of the knee, and the gastrochemius and the hamstrings muscles
stabilize the posterior side of the knee.
Some common injuries to the knee injury include:

Knee ligament tears:

Osgood-Schlatter Syndrome:

Patellofemoral Syndrome (PFS):




The most common knee ligament tears involve a “blow” to the lateral side of the
knee. Generally a blow to the lateral side of the knee will result in damage to the medial side of the knee. The
first tissue to tear is the joint capsule, followed by the medial collateral ligament (MCL), and finally the medial
meniscus and the ACL. If all three or four are torn, the knee must have reconstructive surgery.
It is the result of a condition known as osteochondritis, a disease of the
ossification centres in the bones of young children. It affects the epiphyseal plate of the tibial tuberosity. It is
more prevalent in males than females. In growing children, the epiphyseal plates or growth plates allow the bones
to lengthen and increase in size. If the tibial tuberosity becomes irritated and inflamed from overuse (like through
running or jumping) it will cause swelling and discomfort over the patella. This does not affect growth of the
child and does not damage the epiphyseal plates.
The main symptom of patellofemoral syndrome is the gradual onset
of anterior knee pain or pain around the patella. It usually affects adolescents or young adults, and women are
20
often affected more than men. The main is aggravated by running, and lateral movement (such as in volleyball
and basketball).
The Ankle Joint







The ankle joint is a modified hinge joint that is composed of the distal ends of the tibia and fibula resting on the
talus to form the ankle joint.
The ankle joint is responsible for plantar flexion and dorsiflexion.
Inversion and eversion are usually discussed as movements of the ankle joint, but they are actually facilitated by
the transverse tarsal joint of the foot.
The lateral border of the ankle joint (on the fibula side) is called the lateral malleolus, and the medial border (on
the tibia side) is called the medial malleolus.
The important ligaments of the ankle include the anterior and posterior tibiofibular ligaments (which are superior
to the anterior and posterior talofibular ligaments) and the calcaneofibular ligament.
Inversion sprains occur when the ankle is in its weakest position – plantar flexed.
This movement is
essential to most athletic events that include jumping or quick changes in direction. Inversion sprains are
commonly referred to as “twisting your ankle” or “rolling over on your ankle”.
 The ankle is most unstable during plantar flexion, so when you jump up in the air, or plant hard to
change your direction, the ankle plantar flexes with great force coming up and does not return back to a
neutral position as the body comes down, causing the ankle to be inverted past the joint’s normal range
of motion (ROM) and resulting in a sprained ankle.
Eversion sprains are rare because of the strength of the deltoid ligament. This ligament attaches the medial
malleolus to three bones of the foot. This ligament is so strong that, instead of tearing completely, it tears off the
tip of the medial malleolus. The most severe eversion injury is known as a Pott’s fracture which is a break
of the tip of the medial malleolus and a break to the fibula. This is a result of a force on the medial side of the
ankle, causing the deltoid ligament to rip off the tip of the medial malleolus and a break of the fibula. The patient
would be in a cast for 8-12 weeks followed by physical therapy.
21