Pinched Nerve

Common examples of conditions which are caused by nerve related pain or injury include carpal tunnel syndrome, thoracic outlet syndrome, sciatica, piriformis syndrome. In all of these conditions inflammation or tightness/ spasm in the surrounding muscles and connective tissues leads to the nerve becoming compressed and irritated. Compression of peripheral nerve fibres causes pain and altered sensation (i.e. pins/needles, numbness, weakness) in the areas supplied by the nerve.

Treatment

Treatment of a pinched nerve is aimed at releasing the structures which are compressing the nerve such as the muscles and connective tissue. In most cases this involves the use of manual therapy techniques, dry needling and corrective stretches.

Facet Joint Syndrome

The facet joints lie between and behind adjacent vertebrae and allow for bending, twisting and rotational movements of the spine. Under normal circumstances these joints glide smoothly over one another allowing for pain free movement in all available directions. Occasionally these joints are placed under prolonged periods of stress (i.e. extended periods of sitting with poor posture or prolonged standing or lifting and twisting). This may cause sudden overloading of the joint, the joint surfaces can become compressed together leading to inflammation, irritation and reduced joint motion or a gradual disruption of the joint resulting in a slower onset of pain.

Symptoms of Facet Joint Syndrome

Typically patients complain of localised pain in the area of the injured joint(s). Occasionally there can be referred pain into the buttocks, thigh or groin. Pain is often aggravated by movements which compress or stress the injured facet joint, i.e. bending backwards or to the side that is injured. The injured area usually feels stiff and movement is restricted due to pain.

Treatment of Facet Joint Syndrome

Facet joint injuries can be treated with a combination of hands on manual therapy and corrective strengthening and movement correction exercises. Hands-on manual therapy usually consists of joint mobilisation or manipulation. Manual soft tissue techniques may be employed to restore normal joint movement and alleviate symptoms of muscle tension. Spinal decompression therapy may also be used to provide gentle and painless separation of jammed facet joints.

Nerve Pain

Nerve pain may be the result of a compressed, irritated nerve or due to underlying nerve pathology. Symptoms of nerve injury may include pain, burning, pins and needles, numbness and/or increased sensitivity. 

Nerves may become injured or compromised when other structures in the body start to impinge on them. Common examples include a bulging disc or degenerative changes in the spine which can compress the nerve root as it exits the spine. Occasionally increased tone of a muscle through which a nerve passes may cause compression.

Trauma or a stretch injury might occur to a nerve, e.g ‘a stinger’ caused in contact sports. In more severe cases of nerve injury there will be persistent pain in the area of distribution of the nerve and there may be weakness in the muscles innervated by the nerve.

Treatment of Nerve Pain

Our physiotherapists will look to ascertain the cause of your nerve pain. Once the cause is known a number of treatment techniques may be employed in isolation or in combination to help relieve the symptoms of nerve pain. These include joint mobilisation, myofascial release or dry needling of tight soft tissue structures, passive soft tissue mobilisation, and neural mobilisation techniques.

Whiplash

Whiplash is an injury which results from sudden acceleration-deceleration forces on the neck. The term encompasses a variety issues affecting muscles, joints, bones, ligaments, discs and nerves.

Causes of Whiplash

Whiplash generally results from a traumatic event involving sudden acceleration-deceleration forces. The most common cause for whiplash is a motor vehicle accident. Other potential causes may include roller-coasters, bungy jumping or a sports-related collision.

What are the Symptoms of Whiplash?

Symptoms and severity of whiplash can vary significantly between people. The most commonly reported symptom is neck pain or stiffness. This can occur anywhere from immediately after the injury to several days later.

Symptoms may include:

• Neck pain or stiffness

• Headache

• Shoulder pain, arm pain or upper back pain.

• Dizziness

• Altered sensation

• Weakness

• Visual disturbances

• Hearing difficulties

• Difficulty speaking or swallowing

• Difficulty concentrating

How is Whiplash Diagnosed?

Whiplash is a clinical diagnosis based of your history of injury and clinical testing. Radiological tests may be useful to identify injury to specific structures such as a fractured vertebra, disc injury, muscles or ligaments.

Red Flags

Due to the traumatic nature of a whiplash injury; there is a risk of more urgent or sinister injuries which need to be ruled out before undergoing treatment. Your physiotherapist and GP are trained to detect anything abnormal which warrants further investigation, however please notify a health professional if you have (or develop) any of the following:

• Bilateral pins and needles

• Gait disturbances

• Progressively worsening weakness or sensation problems

• Pins and needles or numbness in the face

• Difficulty speaking or swallowing

• Drop attacks (falling without loss of consciousness) or fainting

• Bladder or bowel problems

Treatment

Research shows the most effective way to treat your injury is with a combination of treatment options which are tailored to your individual dysfunctions. Research evidence supports various treatment approaches. Your best treatment direction should be guided by an expert in the rehabilitation such as a musculoskeletal physiotherapist who specialises in neck injuries or whiplash. 
Potential treatment methods for whiplash include:

• Continuing your normal daily regime: Acting Normal!

• Active treatment guided by your physiotherapist.

• Exercise to encourage flexibility, strength and good posture.

• Fine neck muscle and proprioception retraining programs guided by a physiotherapist.

• Acupuncture or dry needling for pain relief.

• Education on the injury: asking questions!

• Joint mobilisation or manipulation to loosen stiff joints.

• Medication to assist your pain, muscle tension or to assist you psychologically.

• Psychologist advice.

• Vestibular rehabilitation if dizziness is one of your symptoms.

• Soft tissue massage may assist for short-term muscle tension relief.

Bursitis

Bursitis is an inflammatory condition that affects the bursae. These are small fluid filled sacs (balloon like) that lie between tendons and bones.

These bursae help to reduce friction and provide cushion as the tendon glides over the bone. There are numerous bursae located in different joints throughout the body, however areas typically affected by bursitis are the shoulder, elbow, hip, knee and distal end of the achilles tendon.

Bursitis usually occurs due to repetitive strain and excessive pressure.

Treatment of bursitis consists of rest from any aggravating activities and usually a course of anti- inflammatories prescribed by a qualified licensed medical practitioner. There may be underlying bio-mechanical causes for why the bursae is being overloaded.

Our Chartered Physiotherapists will provide a thorough bio-mechanical assessment and prescribe any necessary exercises to help correct poor movement patterns which are contributing to the condition.

Muscle Strains

Muscle strains can occur in any part of the body. Muscles work to stabilise/support the body while others are concerned with movement. Occasionally muscles may become overloaded as a result of vigorous activity or overuse.

Muscle Strains or torn muscles, lead to inflammation and pain at the site of injury. On other occasions the pattern of muscle activation can become dysfunctional resulting in a muscle overworking and becoming sore as a consequence. Particular movements of an affected area can stretch or place stress on the injured muscle.

Muscle Strains are classified as follows:

Grade 1: A strain involving a small number of muscle fibres and causes localised pain but no loss in strength.

Grade 2: A tear of a significant number of muscle fibres with associated pain and swelling. Pain is reproduced on muscle contraction.  Strength is reduced and movement is limited.

Grade 3: A complete tear (rupture) of the muscle. Swelling/bruising is present. May have complete loss of function depending on where in the body the injury has occurred.

Tendon Injuries

Typically, tendon injuries occur in three areas:

• musculotendinous junction (where the tendon joins the muscle)

• mid-tendon (non-insertional tendinopathy)

• tendon insertion (e.g. into bone)

Non-insertional tendinopathies/tendonosis tend to be caused by a cumulative microtrauma from repetitive overloading eg overtraining.

What is a Tendon Injury?

Tendons are the tough fibres that connect muscle to bone. Most tendon injuries occur near joints, such as the shoulder, elbow, knee, and ankle. A tendon injury may seem to happen suddenly, but usually it is the result of repetitive tendon overloading. Health professionals may use different terms to describe a tendon injury. You may hear:

Tendinitis (or Tendonitis): This actually means “inflammation of the tendon,” but inflammation is actually only a very rare cause of tendon pain. But many doctors may still use the term tendinitis out of habit.

The most common form of tendon injury is tendinosis. Tendinosis is a non-inflammatory degenerative condition that is characterised by collagen degeneration in the tendon due to repetitive overloading. These, therefore, do not respond well to anti-inflammatory treatments and are best treated with functional rehabilitation. The best results occur with early diagnosis and intervention.

What Causes a Tendon Injury?

Most tendon injuries are the result of gradual wear and tear to the tendon from overuse or ageing. Anyone can have a tendon injury, but people who make the same motions over and over in their jobs, sports, or daily activities are more likely to damage a tendon.

Your tendons are designed to withstand high, repetitive loading, however, on occasions, when the load being applied to the tendon is too great for the tendon to withstand, the tendon begins to become stressed.

When tendons become stressed, they sustain small micro tears, which encourage inflammatory chemicals and swelling, which can quickly heal if managed appropriately.

However, if the load is continually applied to the tendon, these lesions occurring in the tendon can exceed the rate of repair. The damage will progressively become worse, causing pain and dysfunction. The result is a tendinopathy or tendinosis.

Researchers current opinion implicates the cumulative microtrauma associated with high tensile and compressive forces generated during sport or an activity causes a tendinopathy.

For example, in explosive jumping movements, forces delivered to the patellar tendon can be eight times your body weight. Cumulative microtrauma appears to exceed the tendon’s capacity to heal and remodel.

What are the Symptoms of Tendinosis?

Tendinosis usually causes pain, stiffness, and loss of strength in the affected area.

The pain may get worse when you use the tendon.

You may have more pain and stiffness during the night or when you get up in the morning.

The area may be tender, red, warm, or swollen if there is inflammation.

You may notice a crunchy sound or feeling when you use the tendon.

The tendon is often thickened.

Tendinosis Phases

The inability of your tendon to adapt to the load quickly enough causes tendon to progress through four phases of tendon injury. While it is healthy for normal tissue adaptation during phase one, further progression can lead to tendon cell death and subsequent tendon rupture.

1. Reactive Tendinosis

Normal tissue adaptation phase

Prognosis: Excellent. Normal Recovery!

2. Tendon Dysrepair

Injury rate > Repair rate

Prognosis: Good. Tissue is attempting to heal.

It is vital that you prevent deterioration and progression to permanent cell death (phase 3).

3. Degenerative Tendinosis

Cell death occurs

Poor Prognosis – Tendon cells are giving up!

4. Tendon Tear or Rupture

Catastrophic tissue breakdown

Loss of function.

Prognosis: very poor.

Surgery is often the only option.

It is very important to have your tendinosis professionally assessed to identify its injury phase. Identifying your tendinosis phase is also vital to direct your most effective treatment, since certain modalities or exercises should only be applied or undertaken in specific tendon healing phases.

How is a Tendon Injury Diagnosed?

To diagnose a tendon injury, your physiotherapist will ask questions about your past health, your symptoms and exercise regime. They’ll then do a physical examination to confirm the diagnosis. If your symptoms are severe or you do not improve with early treatment, specific diagnostic tests may be requested, such as an ultrasound scan or MRI.

How is Tendinosis Treated?

In most cases, you can start treating a tendon injury at home. To get the best results, start these steps right away:

Rest the painful area, and avoid any activity that makes the pain worse.

Apply ice or cold packs for 20 minutes at a time, as often as 2 times an hour, for the first 72 hours. Keep using ice as long as it helps.

Do gentle range-of-motion exercises and stretching to prevent stiffness.

Have your biomechanics assessed by a physiotherapist.

Undertake an Eccentric Strengthen Programme. This is vital!

Neck Headaches

Neck Headache, or as it is known medically – Cervicogenic Headache, is a secondary headache disorder. In other words, your headache is caused by a neck joint problem.

The good news is that by fixing your neck problem, your neck headache can be alleviated. Researchers feel that neck headache accounts for between 4% to 22% of all headaches seen clinically. (Racicki et al 2013; Watson 2014)

What’s Causes Your Neck Headache?

Your neck headache can originate from a variety of musculoskeletal and neurovascular structures in your upper neck; including the upper three neck joints, C2/3 disc, spinal cord coverings and neck muscles. A dysfunction in these areas can trigger pain signals that travel to your trigeminocervical nucleus (TCN) in your brainstem. This information is then transmitted into your brain and interpreted as a headache (Bogduk 2003).

Upper Neck Joints

The most likely sources of your neck headache is dysfunction of either your upper neck joints, neck muscles or nerves, which trigger pain signals that travel to your trigeminal nucleus in your brainstem, where you interpret the pain signals as a neck headache.
The most common cause of neck headache is dysfunction of your upper three neck joints.

The most common neck joints involved are your:

Atlanto-occipital joint (O-C1),

Atlanto-axial joint (C1/2), and

C2/3 cervical spine joints.

In simple terms, your neck joints can cause neck headache or pain if they are either too stiff or move too much (eg wobbly and unsupported by weak muscles) or are locked in an abnormal joint position eg. locked facet joint or poor posture.

Once your neck joint becomes stressed and painful, the pain signals are referred to the trigeminocervical nucleus in your brainstem… and you start to feel a neck headache or, in some cases, face pain!

Your physiotherapist is an expert in the assessment and correction of neck joint dysfunctions that result in neck headache. Their professional diagnosis and treatment is essential for neck headache sufferers.

Neck Muscle

Your neck and shoulder blade muscles that originate from your neck will cause pain if they are overworking, knotted or in spasm.

Some of your neck muscles overwork when protecting injured neck joints. Other neck muscles become weak with disuse, which places further demand on your overworking muscles resulting in muscle fatigue related symptoms.

Your neck muscles work optimally when they have normal resting tension, length, strength, power and endurance.

Your physiotherapist is expert in the assessment and correction of muscle imbalances that result in neck headache.

Cervical and Occipital Nerves

Nerves in your upper neck may be directly pinched by extra bony growths eg arthritis, disc bulges or swelling. The results can result in nerve irritation or a reduction in neural motion known as neuromechanosensitivity or abnormal neurodynamics.

Irritation of your upper neck structures refer pain messages along the nerves and cause your headache.

In simple terms, your neck is the “switch”, nerves are the “power cords” and your headache is where the “light” comes on.

What are the Symptoms of Neck Headache?

Neck headaches can often be misdiagnosed or confused with other sources of headache, including migraine, since the head pain is typically felt in the same area as a migraine.

It is really the interpretation from your headache physiotherapist of the whole combination of your symptoms plus the findings of your physical examination that will confirm a neck headache diagnosis

Commonly, neck headache sufferers will usually notice:

Tenderness at the top of their neck and base of the skull.

Neck stiffness or a mild loss of movement, although this is sometimes is only subtle and needs to be confirmed during your physiotherapist’s physical examination.

One of the main differences between neck headache and migraine is that physiotherapy treatment of your neck is able to alter or relieve your headache immediately.

Common Characteristics of a Neck Headache?

The following symptoms are characteristics of a neck headache. You may experience any one or several of these symptoms

• Your headache may seem to radiate from the back to the front of your head.

• Your headache be provoked or eased by a neck movement, a sustained posture, stomach sleeping or with your head turned to one side.

• Your headache normally appears to be worse on one side of your head. The side is normally constant and does not swap sides.

• Your headache appears to temporarily ease up when you apply pressure or you massage your neck or the base of your skull.

If you experience any of the above symptoms, you are more likely than not to be suffering a neck headache. Please inform your physiotherapist and they will assist you.

What if Your Neck Isn’t Sore?

Even if your neck isn’t sore or painful, you can still experience neck headaches. It is important to remember that your neck joints may not be sore at rest, but they may be tender to touch or painful on movement.

Neck joints that are sore at rest will normally be very tend to touch and painful at the extreme of movement. Obviously, this scenario is a more severe neck headache.

If your headache or migraine has been present for years and your neck has not been examined, then a thorough neck examination is recommended and is appropriate to either confirm and treat your neck headache or exclude a neck disorder as the cause of your headache.

How is a Neck Headache Diagnosed?

Accurate diagnosis is important to guide the correct treatment and management your neck headache. Headache and head pain can have many causes, not just neck headache or migraine. Correctly identifying the cause will lead to better treatment.

Trigger Points

Dr’s Travell and Simons defined a myofascial trigger point as a “hyperirritable spot in a skeletal muscle”. The spot is painful on compression and can give rise to characteristic referred pain, referred tenderness, motor dysfunction and autonomic phenomena.

Myofascial trigger points are commonly seen in both acute and chronic pain conditions. Hendler and Kozikowski suggest that myofascial trigger points as the most commonly missed diagnosis in chronic pain patients.

Why Do Trigger Points Cause Pain?

According to Dr. Gunn, ‘Shortening in muscles acting across a joint increases joint pressure, upsets alignment, and can precipitate pain in the joint, i.e. arthralgia.’ Muscle release, massage or dry needling of the ‘shortened’ muscle band can cause an immediate palpable relaxation. A sense of release and increased range of motion is often experienced by the patient.

When used in conjunction with motor control retraining and postural and movement retraining, the release obtained from treatment can be long lasting.

How Are Trigger Points Treated with Dry Needling?

Over the years it has been shown that it is possible to deactivate triggers points by injecting them with a large number of varying substances, including saline (salt water) placebo. It has been subsequently suggested then, that only consistent factor is that the pain relief is obtained from the stimulation of the needle used for the injection itself, rather than the drug or saline solution used. This mechanical needle stimulation of the trigger point without the use of a drug is known as Dry Needling!



The needle sites can be at the epicentre of taut, tender muscle bands, or they can be near the spine where the nerve root may have become irritated and supersensitive. Penetration of a normal muscle is painless; however, a shortened, supersensitive muscle will ‘grasp’ the needle in what can be described as a cramping sensation. The result is a stimulation of the stretch receptor in the muscle (muscle spindle), producing a reflex relaxation or lengthening response.

Arthritis - Osteoarthritis

Arthritis is an umbrella term for over 100 medical conditions that affect your joints. Arthritis-related problems include pain, stiffness, inflammation and damage to joint cartilage (the tissue that covers the ends of bones, enabling them to move against each another) and surrounding structures. This can result in joint weakness, instability and deformities that can interfere with the most basic daily tasks such as walking, driving a car and preparing food.

As the population ages, the number of people with arthritis is growing. There is a widely held belief that arthritis is simply a consequence of age. But it is not only a natural part of ageing. It may be associated with an injury, there may be some genetic predisposition or other factors may come into play.

Research suggests that early intervention can delay the onset of the disease and may reduce the number of cases of osteoarthritis.

Common causes of arthritis

While there are about 100 forms of arthritis, the three most common causes account for 95% of all arthritis. These are:

• Osteoarthritis- a wear and tear process related to time or possible injury.

• Rheumatoid Arthritis- a disease process that is systemic.

• Psoriatic Arthritis- a disease process that is systemic.

• Less Common Causes of Arthritis

• Ankylosing Spondylitis

• Lupus

• Juvenile Arthritis

• Scleroderma

Repetitive Strain Injury

Repetitive strain injury (RSI) is a general term used to describe the pain felt in muscles, nerves and tendons caused by repetitive movement and overuse.

It's also known as work-related upper limb disorder, or non-specific upper limb pain. The condition mostly affects parts of the upper body, such as the:

• forearms and elbows 

• wrists and hands 

• neck and shoulders

• Symptoms of RSI

The symptoms of RSI can range from mild to severe and usually develop gradually. They often include:

• pain, aching or tenderness

• stiffness

• throbbing 

• tingling or numbness 

• weakness 

• cramp 

• At first, you might only notice symptoms when you're carrying out a particular repetitive action.

But without treatment, the symptoms of RSI may eventually become constant and cause longer periods of pain. You may also get swelling in the affected area, which can last for several months. 

Stress Fracture

Stress fractures are small micro-cracks in the bone which result in localised pain and loss of function. They are a common injury in sports activities where there is repetitive high impact loading of the bone and its surrounding muscles, such as repeated jumping and long distance running.

Although the most common sites for stress fracture are in the foot and lower limb, they can also occur in the pelvis, lumbar spine, thorax and upper limb.

Stress Fracture Treatment

The treatment of stress fractures requires a period of avoidance from the precipitating activity, your physiotherapist will encourage active rest and performance of pain free exercise activities to maintain fitness and promote healing.

Depending on the site of injury the majority of stress fractures will heal within 8 weeks of beginning relative rest. It is important that you seek the help of a Chartered Physiotherapist to aid your recovery and identify any extrinsic (outside the body) or intrinsic (bodily) factors which contributed to the fracture.

Rest alone is not sufficient, failure to address the underlying causes may expose the individual to a recurrent fracture.

Avulsion Fracture

Avulsion fractures occur when a small fragment of bone attached to a ligament or tendon gets pulled away from the main body of bone. In most cases your physiotherapist will be working in conjunction with the expertise of an orthopaedic consultant or sports physician.

Common areas where avulsion fractures can occur include head of the 5th metatarsal, the navicular bone on the inside of the foot, the hip flexors especially in the young athlete and the ischial tuberosity or ‘sitting bone’ where your hamstring tendon originates.

Treatment

Initial treatment following an avulsion fracture usually consists of rest and icing of the area injured. In most cases your physiotherapist will be working in conjunction with the expertise of an orthopaedic consultant or sports physician.

Your physiotherapist will introduce you to a graded exercises program to help restore range of motion, increase strength and promote bone healing. In the majority of cases conservative treatment through physiotherapy has been shown to offer best results.

However in cases where the avulsed bone has been pulled too far away from the main body of bone healing can be more problematic and surgical intervention may be needed.

Ligaments

Ligaments link bones to other bones and provide support to joints. They allow a normal range of movement to occur within a joint, but prevent unwanted movement that would render the joint unstable. In order to fulfil this function ligaments must possess immense mechanical tensile strength. Ligaments are classified as dense connective tissue, and they consist of a protein substance called collagen. The organisation of collagen fibres gives the ligament its tensile strength.

Another function of ligaments is to provide proprioceptive input to the brain that allows a person to know what position the joints are in, without having to look. This helps to perform the complex coordinated activities needed for sport.
A normal ligament consists of:

90% Type 1 collagen

9% Type 3 collagen

1% fibroblast cells (the cells that produce collagen)

Type 1 collagen is mature collagen tissue and has the greatest tensile strength.

Type 3 collagen is immature collagen tissue and does not provide a great deal of tensile strength to the ligament. After being laid down by fibroblast cells it takes approximately three months for Type 3 collagen to mature into Type 1 collagen. As with other cells in the body, this process of renewal occurs continually.

When ligament tissue is examined under the microscope it can be clearly observed that the collagen fibers are arranged in a longitudinal pattern to resist the stress that is placed upon the ligament. The arrangement of the collagen fibers mean that a great deal of force is required to damage ligaments. This force produces structural damage to the ligament, which is known as a ligament sprain.

Ligament sprains are classified as follows:

Grade 1 Sprain

There is damage to a few collagen fibres, producing a local inflammatory response. This is characterised by pain over the affected ligament, some swelling and minor loss of function.

Grade 2 Sprain

There is damage to a more extensive number of collagen fibres. This produces a more marked inflammatory response characterised by intense pain and joint effusion (swelling).

Grade 3 Sprain

The damage to collagen fibres is such that there is a complete rupture of the ligament. This produces intense pain, joint effusion and marked joint instability. In some circumstances surgery may be necessary to restore joint stability.

As with other soft tissue injuries, ligament healing consists of inflammation followed by repair and then remodelling.

Inflammatory Phase

The inflammatory phase follows trauma to collagen fibers and lasts for 3-5 days, depending on the severity of the injury. Chemicals are released which produce pain, and there is bleeding in the tissues. This, together with fluid from damaged cells, produces swelling within the joint, putting pressure on nerve endings and causing more pain.

Rehabilitation time can be greatly reduced by appropriate treatment in this acute stage. This consists of protecting the injured part from further damage, rest from activity involving the injured part, ice (never apply ice directly to the skin), compression and elevation can be useful.

Repair Phase

The repair phase is mediated by blood clotting over the damaged tissue. Blood platelets form a mesh to initiate healing. Also present in the blood clot are fibroblast cells, which proliferate and begin to lay down Type 3 (immature) collagen tissue, between 3-21 days after the injury. Appropriate physiotherapy in this phase has been shown to encourage fibroblast activity that ultimately provides a structurally stronger ligament.

Remodelling Phase

The remodelling phase follows the repair phase and can last for up to a year. It involves maturation of collagen tissue from Type 3 to Type 1 and realignment of collagen tissue.

When it is first laid down, the collagen tissue is haphazard and does not possess a lot of tensile strength. The ligament gradually becomes stronger through being subjected to controlled strain in a functional pattern, which aligns the fibres in a longitudinal fashion. Physiotherapy, in the form of controlled exercises progressing to functional activity can aid this process of remodelling.

Because the remodelling phase lasts for up to a year, there is a potential weakness in the ligament and a risk of re-injury. This risk is reduced by providing additional stability with  taping/strapping or use of a brace, increasing the strength of muscles which also provide support to the joint, and by doing proprioceptive exercises to increase the patient’s sense of joint positioning.