Medical symptom checker - Accessory muscle use

Medical symptom checker - Accessory muscle use

Accessory muscle use is characterized by the use of internal intercostal muscle, abdominal muscle, sternocleidomastoid muscle, trapezius muscle, scalene muscle and pectoralis muscle while breathing. In other terms, extra effort is required for the patient to breath normally. The function of the accessory muscle is to stabilize the thorax during ventilation.
Contraction of the accessory muscle may also happen in normal scenario such as coughing, defecating, singing, exercising and talking. An increase use of these muscles may indicate acute respiratory distress and weakness of the diaphragm that is associated with the chronic respiratory condition. The severity of the condition is associated with the extent of the usage of the accessory muscle.

Anatomically, sternocleidomastoid muscle is originating from the media third of the clavicle and manubrium sterni and inserted into the occipital bone and mastoid process of the temporal bone. It is innervated by C2 and C3 nerves and spinal part of the accessory nerves. Sternocleidomastoid muscle are two muscles that join and act together to flex the neck and extend the head. In another case, the muscle will rotate the head in the opposite sides.

Scalene muscle is divided into 3 parts such as scalenus anterior, scalenus medius and scalenus psoterior. Scalenus anterior muscle is originating from the transverse processes of the 3rd, 4th, 5th and 6th cervical vertebrae. It is inserted to the first rib and innervated with C4, C5 and C6 nerves. It is involved in lateral flexion and rotation of the cervical part of the vertebral column and the elevation of the first rib.

Scalenus medius is originating from the transverse processes of the upper 6th cervical vertebra and inserted to the first rib. It is innervated with anterior Rami of the cervical nerves. It involves in lateral flexion and rotation of the cervical part of the vertebral column and the elevation of the first rib.

Scalenus posterior is originating from the transverse process of the lower cervical vertebrae . It is inserted to the 2nd ribs and innervated by anterior Rami of the cervical nerves. It is involved in lateral flexion and rotation of the cervical part of the vertebral column.

Trapezius is originating from the ligamentum nuchae, occipital bone, spine of all thoracic vertebrae and spine of the 7th cervical vertebrae. Trapezius is inserted into the lower and middle fibers and into the spine of the scapula and acromion as well as lateral third of the clavicle upper fiber. It is innervated with C3 and C4 nerves (sensory) and spinal part of accessory nerves with nerve roots from 9th cranial nerve (spinal part). It is involved in the pulling of the medial border of the scapula downward. The middle fiber involved in the pulling of the scapula medially while the upper fiber will elevate the scapula.

Pectoralis muscle is divided into pectoralis major and pectoralis minor. Pectoralis major is originating from the sternum, clavicle and upper six costal cartilages. It is inserted to the lateral lip of the bicipital groove of the humerus. It is supplied by the lateral and medial pectoral nerves from the brachial plexus. The nerve roots from C5, C6.C8 and T1 nerves. It involves in adduction of the arm and medial rotation of the arm.

Pectoralis minor is originated from the 3rd, 4th, and 5th ribs and inserted into the coracoid process of the scapula. It is innervated by the medial part of the pectoral nerve from the brachial plexus. The nerve roots from the C6, C7 and C8. It is presented as a depress point in a shoulder joint. It is involved in the elevation of the ribs.

The intercostal muscles are divided into external intercostal muscle, internal intercostal muscle and innermost intercostal muscle.

The external intercostal muscle is a muscle that is originating from the inferior border of the rib. The muscle fiber is running downward and forward. It is inserted to the superior border of the rib below. It is innervated by intercostal nerve. It is involved in the raising of the ribs during inspiration while the first rib is fixed which increase the transverse and anteroposterior diameter of the thorax. They will lower the ribs during expiration when the last rib is fixed by abdominus muscle.

The internal intercostal muscle also originates from the inferior border of the rib and inserted to the superior border of the rib below. It is also running downward and backward. It is innervated by intercostal nerves. It is also involved in the raising of the ribs during inspiration while the first rib is fixed which increase the transverse and anteroposterior diameter of the thorax. They will lower the ribs during expiration when the last rib is fixed by abdominus muscle.

The innermost intercostal muscle is originated from the adjacent ribs. It is inserted onto adjacent ribs. It is innervated by the intercostal nerves and involved in assisting internal and external intercostal muscles.


Trapezius muscle
Trapezius muscle
scalene muscle
scalene muscle

History and complains are taken from the patient. The patient typically complains of fatigue, lethargy and feel the sternness and excessive use of the muscle of the neck , shoulder and abdomen. They complain of soreness at the subcutaneous regions. Basically the initial step if the patient condition allow is to take a complete history from them. Ask about the sites of soreness, the onset of the symptoms, the characteristic of the pain/soreness, any radiation of the pain, when it happens, how frequently did it happen , what makes it worst and any associated condition such as chest pain, dyspnea, fever and cough. The severity of the condition also needs to be assessed.

The focus on the patient medical history such as the present of any respiratory condition/disease in the past such as pneumonia, asthma or COPD or any cardiac condition in the past such as pulmonary edema and heart failure or any neuromuscular disorder such as amyotrophic lateral sclerosis that affect the function of the respiratory muscle . Ask the patient about any autoimmune condition that he may suffer such as rheumatoid arthritis, systemic lupus erythematosus and collagen vascular disease. It is also important to point out if the patient had any history of trauma or injury to the spine or any respiratory support or performing pulmonary function test recently.

History of the drug intake and allergic also are required. The main focus of the history taking is to ask about the smoking habit which will predispose to the respiratory condition such as COPD. Family history such as neurofibromatosis and cystic fibrosis may lead to infiltrative lung disease which is characterized by excessive use of accessory muscle. As a result it is very important to point this condition out while taking a history from the patient.

A complete set of respiratory and cardiovascular examinations are performed onto the patient.

The doctor should focus and observe for any abnormality in the respiratory rate, pattern and depth of breathing, colour, temperature and turgidity of the patient's skin. Any sign of clubbing also needs to be noted.

The common causes of excessive use of accessory muscle are adult respiratory distress syndrome, asthma, pneumonia, emphysema, pulmonary embolism, pulmonary edema, pneumothorax, spinal cord injury, amyotrophic lateral sclerosis and thoracic injury.

Adult respiratory distress syndrome is a life threatening condition. The patient typically complains of shortness of breath, (dyspnea). On examination, the patient is excessively sweating (diaphoresis), used the accessory muscle to breath due to hypoxia and present of intercostal, Sternal and supracostal retraction. The patient may also appear tachypneic. On auscultation diffuse crackles are heard all over the lung region. In the worst case scenario, patients may suffer from anxiety attack, altered mental status and tachycardia.

Asthma is one of the causes of excessive use of the accessory muscle. In acute asthmatic attack, patient present with dyspnea and productive cough. On examination patient may appear tachycardia, excessively sweating (diaphoresis), apprehensive (due to air hunger), and tachypnoeic . On inspection cyanosis and nasal flaring are common as well as excessive use of accessory muscle. Auscultation of the patient‘s lung may reveal widespread rhonci, wheeze and absent of breath sound. Barrel chest is more common with chronic asthma.

Pneumonia is caused by infection of the respiratory tract. The patient typically presents with dyspnea, productive cough, chest pain, tachycardia, tachypnea, cyanosis, accessory muscle use, diaphoresis, fine crackle and expiratory grunting. The patient will initially present with high fever and chills.

Emphysema is part of COPD. It is the most common causes of excessive accessory muscle use. The patient typically complains of dyspnea on exertion. In severe case, dyspnea may occur at rest. On examination, patients may present with barrel shape chest, malaise, anorexia and weight loss. The patient will also display the pursed lip breathing (pink puffer) and appear to be tachypneic. Auscultation may reveal distant heart sounds and diminished breath sound and hyper resonance is detected on percussion.

Pulmonary embolism is a life threatening condition. The presentation varies according to the location and sizes of the emboli. On examination the patient typically appears restless and complaints of productive cough. Besides accessory muscle use, patient also present with low grade fever, tachycardia, tachypnea and substernal chest pain which is pleuritic in nature. A patient that presented with hemoptysis, distention of the neck vein, syncope, cyanosis and scattered crackles as well as wheezing indicates the presence of a large emboli.

Pulmonary edema is also one of diagnosis of accessory muscle use. Patient who suffers from pulmonary edema may present with the feeling of restlessness, cyanotic, clammy, cold skin, ventricular gallop, tachycardia, tachypnea, dyspnea, orthopnea, wheezing, crepitant crackle and cough with frothy pink sputum.

A patient who suffers from pneumothorax especially tension pneumothorax with chronic lung disease may excessively increase the use of accessory muscle. Tension pneumothorax is a dangerous situation as it may lead to cardiopulmonary arrest due to reduction in blood pressure and elevation of the neck vein, Other signs and symptoms may include dyspnea, chest pain, unilateral decrease in breath sound and unilateral decrease in chest movement and tracheal deviation.

Traumatic situation such as spinal cord injury and thoracic injury may also lead to excessive accessory muscle use. Spinal cord injury which involves the injury of the C3 to C5 vertebrae may lead to an increase in the use of accessory muscle. Injury to the C3 and C5 vertebrae may lead to damage of the diaphragm and upper respiratory muscle. Besides that an injury to the C3 and C5 (lower cervical vertebrae injury) may also lead to Horner syndrome that present with facial anhidrosis, a pupil that is constricted and unilateral ptosis ). Other signs and symptoms that present may include loss of proprioception, pain and temperature as well as motor function, spasticity, bilateral and unilateral Babinski ‘s reflexes and hyperactive deep tendon reflexes.

Thoracic injury may also lead to an increase in the accessory muscle use. The patient may present with signs of significant blood loss such as tachycardia and hypotension. Besides that, there will be an obvious bruising and chest wall wound as well as asymmetrical chest wall movement, agitation, cyanosis and patient complains of chest pain and dyspnea.

Amyotrophic lateral sclerosis is a condition that present with an increase used of the accessory muscle. Amyotrophic lateral sclerosis is a progressive motor disorder that affects the diaphragm and accessory muscle. It carries a poor prognosis. Hyperactive deep tendon reflexes, weakness, muscle atrophy, fasciculation, spasticity and bilateral Babinski’ reflex are the common signs associated with amyotrophic lateral sclerosis. The patient may also present with coordination problems and impairment or difficulty with chewing, speech, breathing and swallowing. The patient may also present with excessive drooling, choking and urgency as well as urinary frequency.

Beside that, intermittent positive pressure breathing, pulmonary function test and incentive spirometry may lead to an increase in the respiratory effort and the accessory muscle used.

Any cases of upper airway obstruction caused by foreign bodies, edema and bronchospasm may lead to respiratory distress and increase the use of accessory muscle. Other disorder such as asthma, pertussis, cystic fibrosis, croup and acute epiglottitis may also lead to upper airway obstruction. Accessory muscle use is indicated with abdominal, intercostal and supraventricular retractions.

In elderly, accessory muscle use has become part of normal breathing as the rib cage has lost its elasticity. (Age related loss of elasticity of the rib cage).

The patient should be prepared for the following tests such as full blood count, culture of the sputum, arterial blood gas, chest x- ray, lung scans and pulmonary function test.




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Comments 2 comments

jhunpaler profile image

jhunpaler 4 years ago from Philippines

informative hub :) voted up and useful :)


JasonL99 profile image

JasonL99 4 years ago

Some quite detailed information - you certainly have a very good grasp of medical knowledge.

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