netter anatomy , pectoralis minor , physiotherapy

PECTORALIS MINOR- THE NEGLECTED MUSCLE

Pectoralis minor ,proactive physiotherapy, kinetic chain

Coutsey : Wikipedia.com

Human body is designed in such an intricate manner that upper limbs are for manipulative activities and lower limbs are for mobility. When each of the body segments is aligned properly it gives a pleasant appearance as well as a disorder free body. While poor posture and muscular imbalance often results into pain and loss of function.

Physiotherapy musculoskeletal assessment format consists of many points in observation, palpation and examination which are extremely important for proper diagnosis, treatment planning and knowing the prognosis. However, many a times while assessing shoulder and cervical region; one of the important muscle- Pectoralis Minor is often neglected. A shortened pectoralis minor muscle commonly contributes to muscular imbalance and pain in shoulder and cervical region.

Poor upper body posture is many a times referred to as a ‘forward head posture’, ‘slouched posture’, ‘poking chin posture’, or ’rounded shoulder posture’ and is considered to be a potential etiological factor in the pathogenesis and perpetuation of many clinical syndromes like Thoracic outlet syndrome, Scapular downward rotation syndrome, Scapular winging & tilting syndrome, shoulder impingement syndrome and also upper cross syndrome involving the neck and shoulder.1, 2

origin insertion of pectoralis minor , neurokinetic

The pectoralis minor attaches at the coracoid process of the scapula and at the third, fourth, and fifth ribs near their sternocostal junctions. A short pectoralis minor muscle increases the muscles passive tension with arm elevation resulting in restriction of normal scapular movements such as external rotation, upward rotation and posterior tipping and this in turn will affect glenohumeral and cervical motion.1, 3

 

Few Clinical tests have been recommended to test for shortening of this muscle.

AT Distance: 1, 4, 5

Pectoralis length test

Courtsey:www.musculoskeletalkey.com

The patient in supine lying, arms by side or resting on abdomen and instructed to relax. With the help of rigid standard plastic transparent right angle, measure the linear distance in millimeters between the posterior border of the acromion and the table. Take care not to exert any downward pressure into the table and place the base on the treatment table and the vertical side adjacent to the lateral aspect of the acromion. A distance greater than 2.54 cm (1 inch) suggests short pectoralis minor.

Pectoralis Minor Length Index (PMI): 1, 4, 5, 6

The PMI is calculated by dividing the resting muscle length measurement by the subject height and multiplying by 100.The resting muscle length is measured between the caudal edge of the 4th rib to the inferomedial aspect of the coracoid process with a measuring tape or sliding caliper. PMI is suggested to reflect a shortened pectoralis minor when 7.65 or lower.

 

Referances :

  1. Jain S, Shukla Y. “To find the intra-rater reliability & concurrent validity of two methods of measuring Pectoralis Minor tightness in Periarthritic Shoulder patients.” Indian Journal Of Physical Therapy 2013;1(2):34-38
  2. Lewis J.S., Valentine R.E. “The Pectoralis minor length test: a study of the intra-rater reliability & diagnostic accuracy in subjects with & without shoulder symptoms.” BMC Musculoskeletal Disorders. 2007; 8:64.
  3. Borstad J.D. “Resting position variables at the shoulder: Evidence to support a posture-impairment association.” Journal of the American Physical Therapy Association. 2006; 86(4):549-557.
  4. Borstad J.D. “Measurement of Pectoralis Minor Muscle Length: Validation and Clinical Application.” Journal of Orthopaedic and Sports Physical Therapy. 2008; 38(4):169-174.
  5. Struyf F., Nijs J., Mottram S., Roussel N., Ann M J Cools, Meeusen R. “Clinical assessment of the scapula: a review of the literature.” Br J Sports Med 2012;0:1–8.
  6. Muraki T, Aoki M., Izu.mi T, Fujii M., Hidaka E., Miyamoto H. “Lengthening of the pectoralis minor muscle during passive shoulder motions & stretching techniques: a cadaveric biomechanical study.” Phys Ther. 2009; 89(4).
  7. Pic : Netter`s Anatomy

 

Shoulder joint

Clinical assessment of scapula

Upper limb is designed in such a way that there is ample amount of mobility which is required for manipulative activities that are a part of daily functional activities. In recent days there is increased interest on the role of scapula, its related pathologies and how entire upper extremity function is dependent on the controlled movement of scapula.

For a full, efficient as well as atleast functional range of motion of entire upper limb, scapula plays many roles in facilitating optimal shoulder function by glenohumeral integration, motion on thoracic wall and as a part of scapula-humeral rhythm. With good proximal control there is good distal mobility. Any alterations in the activity of scapula hamper the control over all upper limb activities leading to pain, impingement and other clinical syndromes which gradually causes disability.

 

Observable alterations in the position of the scapula & the pattern of scapular motion in relation to thoracic cage are called scapular dyskinesis. It causes many clinical dysfunction of the shoulder leading to disabilities.

 

Causes of Scapular Dyskinesia:

 

  1. Bony injuries or abnormalities- Types of acromion process or postural alteration 
  2. .Alteration of muscle function- upper cross syndrome, inhibited muscle- serratus anterior, lower fibres of trapezius, rhomboids, deep neck flexors, force couples.

 

  1. Contracture & other flexibility problems- pectoralis minor & major, joint capsule, upper fibres of trapezius, levator scapula

 

  1. Nerve injury/ proprioceptive dysfunction- long thoracic nerve, spinal accessory nerve

 

 

Classification of Scapular Dyskinesia:

 

               (Slideshare.net)

  • Type I – Abnormal rotation around transverse axis: commonly found secondary after rotator cuff dysfunction- inferior angle becomes prominent
  • Type II – Abnormal rotation around vertical axis: commonly seen in patients with glenohumeral joint instability- medial border becomes prominent
  • Type III – Abnormal superior translation of entire scapula: commonly seen in rotator cuff dysfunction and deltoid-rotator cuff force imbalances- superior border becomes prominent
  • Type IV- both scapula are symmetrical at rest & during motion; they rotate symmetrically upward with inferior angles rotating laterally away from midline. This indicates scapular control muscles are not stabilizing the scapula.

 

 

Types of Winging:

  1. Static winging- winging happens at rest, usually caused by structural deformity of scapula, ribs, clavicle or spine.
  2. Dynamic winging- winging happens with shoulder motion. It can be cause of trapezius weakness or serratus anterior weakness. In case of trapezius weakness, scapula depresses and moves move laterally with inferior angle rotated laterally. In case of serratus anterior weakness, scapula elevates amd move medially with inferior angle rotated medially.

 

One more clinical syndrome exists which is coined as S.I.C.K scapula

S- Scapular mal-position

I- Inferior angle prominent

C- Coracoid pain

K- Dyskinesia

 

Clinical assessment of scapula includes evaluating posture, motion, muscular activation and control and corrective maneuvers. Steps for assessment

  1. History taking
  2. Thoracic and cervical posture – trigger points and flexibility
  3. Check for the shoulder posture- trigger points and flexibility
  4. Shoulder strength – especially supraspinatus, infraspinatus, and subscapularis, Serratus anterior, lower trapezius
  5. Shoulder ROM @ 0 and 90 degrees – GIRD
  6. Scapula position @ rest
  7. Scapula position during active abduction and flexion – especially watch descending phase
  8. Scapulothoracic bursitis

 

 

Few important tests include Lennie test, Lateral scapular slide test, Scapular assistance test, scapular isometric pinch test, wall push test, Labral tests, impingement tests, tendinitis tests, etc.

 

References

  • Kibler B, McMullen J. “Scapular dyskinesis and its relation to shoulder pain”. J Am Acad Orthop Surg. 2003;11:142-151.
  • Magee DJ. “Shoulder. Orthopaedic Physical Assessment.” 5th Philadelphia: WB Saunders. 2012; 231-360.

 

Static Postural Assessments

Static posture define as how individuals physically present themselves in stance. It is reflected in the alignment of the body.

Posture can be thought of as static or dynamic. Static posture means how individuals physically present themselves in stance which  could be considered the base from which an individual moves. It provides the foundation or the platform from which the extremity moves.

Dynamic posture is reflective of how an individual is able to maintain posture while performing functional tasks.

We will only discuss static posture here.

Systemic approach to assess static posture.

Static postural assessments require a strong visual observation skill from the clinicians. This can be developed with time and practice. Generally, and  static postural assessments begin at the feet and travel upward toward the head. Clinicians should observe from anterior, posterior and Lateral view.

Basic check point of body region that needs to consider while assessment.

  1. Foot and ankle
  2. Knee
  3. Lumbo-pelvic-hip complex (LPHC)
  4. Shoulders
  5. Head/cervical spine

A static postural assessment is a simple yet effective tool to quickly “size up” your client. Consider yourself a detective looking for structural deviations within a kinetic chain. Many muscle imbalances can be easily identify from the deviations noted in the static postural assessment.

Using a static postural assessment on an initial evaluation of your client will give you a “big picture” view of how that individual uses his or her body day in and day out. Consider the body as a road map.

There are several questions in our mind that

  1.  How have these alterations distorted the feedback from the proprioceptors?
  2.  How has the altered alignment affected the function of the soft tissue?
  3. Has the fascia been overloaded?
  4. Have compensatory muscle imbalances been generated creating altered length-tension relationships, altered force production, synergistic dominance, and altered reciprocal inhibition relationships?
  5. How have these changes affected the entire kinetic chain and overall coordination of movement within the limbs and between the limbs and the trunk?

The static postural assessment is the first step in assessing the biomechanical and neuromuscular pieces of the puzzle necessary to create a program for functional re balancing for your client.

By looking on patient’s posture clinicians have easy to identify on Which muscle they have to work regarding condition.  By looking from different view of standing position one should easly identify the over active and under active muscle group. These will help in clinicians to reach functional goal.

Coutrsey : corrective exercise essential  : NASM