Prevalence of Pectoralis Minor Muscle Shortening in Pathological Shoulder Condition

 

Jibi Paul¹, Nandhini. L²

¹MPT, PhD, Professor, Faculty of Physiotherapy, ACS Medical College and Hospital Campus,

Dr M.G.R. Educational and Research Institute University, Chennai.

²BPT Intern, Faculty of Physiotherapy, ACS Medical College and Hospital Campus, Dr M.G.R. Educational and Research Institute University, Chennai.

 

ABSTRACT:

Background: Shoulder conditions are caused by trauma or injury, fracture, instability, shoulder subluxation, upper cross syndrome, trapezitis, rounded shoulder, degenerative changes, adhesion formation etc. The purpose of the study was to observe the prevalence of the pectoralis minor muscle shortening on shoulder conditions. Objective: The study was to analyze the prevalence of pectoralis minor muscle shortening in pathological shoulder conditions and also to compare the shortening of pectoralis minor muscle among patients with shoulder conditions. Methodology: The study was an observational study with 60 subjects between the ages of 45-60 years. The study was conducted in outpatient of physiotherapy department in A.C.S medical college and hospital. Both genders were included in this study. Result: The result reported that the pectoralis minor muscle shortening is more on adhesive capsulitis with mean value of 6.02, than other conditions of rounded shoulder, upper cross syndrome, trapezitis, fracture, shoulder subluxation with mean value of 6.49, 7.17, 6.94, 7.04, and 6.94 respectively. Conclusion: Pectoralis minor muscle shortening found significant change on adhesive capsulitis when compare with upper cross syndrome, rounded shoulder, fracture, trapezitis and shoulder subluxation with F value 4.958 and p<0.001.

 

 

INTRODUCTION:

Shoulder joint is one of the common getting affected with musculo skeletal dissorders. Abnormal posture related to spine, head and neck are associated with shoulder positional deformities. Forward head posture, rounded shoulder, slouched posture are familiar clinical features related with shoulder pathological conditions. This in turn affects the movements of shoulder joint due to pain and muscle inbalance, which lead to loss of shoulder function. A shortened pectoralis minor muscle is commonly the part of imbalance^1,2.

 

The pectoralis minor attaches at the coracoids process of the scapula and the third, fourth, fifth rib near the sterno-costal junctions.

 

 

Pectoralis minor shortening has implicated for forward shoulder posture and for shoulder impingement causes a decrease length of pectoralis minor which leads to movement alteration or shoulder pain. Over use of shoulder joint is the main cause for its pathological changes associated with muscle length changes^3,4,5,6.

 

The muscles around the shoulder produce downward rotation, anterior tilt and internal rotation. Opposite group of muscles generate upward rotation, posterior tilt and external rotation. Muscle shortening around the shoulder restricts movements in shoulder joints. Pectoralis minor adaptive shortening has been associated with changes in the resting position of the scapula^7,8.

 

Adhesive Capsulitis: Adhesive capsulitis also known as frozen shoulder is a pain full and disabling disorder of nuclear cause in which the shoulder capsule, the connective tissue surrounding the gleno-humeral joint of the shoulder, becomes inflamed and stuff greatly restricting motion and causing chronic pain. Tightness of the pectoralis major and minor, weakness of deep cervical flexor centrally crosses with weakness of middle and lower trapezius⁹.

 

Trapezitis:

Trapezitis is defined as an inflammatory pain arising from the trapezius muscle causing serve neck spasm. Trapezius is skill to upper back area which helps in the movement of the shoulder such as shrugging and the upward movement of the head. Shoulder Fracture: A broken shoulder is most commonly a fracture humerus. A fracture is the medical term for a broken bone. The humerus is upper arm bone between shoulder and elbow when humerus is fractured or at the ball of shoulder joint, it is commonly known as broken shoulder ¹⁰.

 

Glenohumeral Subluxation:

It is defined as a partial or in complete dislocation that usually stems from changes in mechanical integrity of the joint. In a subluxation, the humeral head slips out of the glenoid cavity as a result of weakness in the elevator cuff or a blow to the shoulder area. Rounded Shoulder: Rounded shoulders are an unnatural posture characterized by an exaggerated curvature of the upper back, often a forward positioning of the head where the shoulder girdle is protracted and the thoracic Kyphosis ¹¹.

 

OBJECTIVE:

The study was to analyze the prevalence of pectoralis minor muscle shorting in pathological shoulder conditions and also to compare the shortening of pectoralis minor muscle between the shoulder conditions.

 

METHODOLOGY:

This was an observational study with comparative study design. Study setting done at A.C.S Medical College and hospital, Chennai. Study size selected for this study was 60 Patients. Sampling method used in this study was convenient sampling method.

 

Inclusion criteria:

All cases with minimum 3 months of symptoms and diagnosed by physician. Both males and females individuals aged 30-50 years with limited shoulder joint movement, Periarthritis shoulder, Trapezitis, old case of Shoulder Fracture and subluxation were selected for this study.

 

Exclusion criteria:

Recent trauma, rheumatoid arthritis and recent surgery cases were excluded.

 

Measurement Tool and Material Used:

Measuring tape was measurement tools; Couch and Chair were the materials used.

 

 

Outcome measure:

Shortening of pectoralis minor muscle.

 

Procedure:

A total number of 60 subjects with pathological shoulder conditions are taken and has been divided into 6 shoulder condition each group with 10 subjects (Upper cross syndrome, Shoulder dislocation, Fracture, Periarthritis shoulder, Trapezitis).

 

These subjects were selected under orthopedic doctor prescription. The subjects were positioned with comfortable sitting position for measurement of pectoralis minor muscle shorting. Pectoralis Minor Index (PMI) is measured from the edge of 4th rib to the infero-medial aspect of corocoid process with measuring tape. PMI is calculated by subject height and multiply by 100 is measured to know pectoralis minor muscle shortening ^{12, 13, 14}.

 

Measuring tape:

A tape measure or measuring tape is a flexible ruler and used to measure distance. It consists of a ribbon of cloth, plastic, fiber glass or metal strip with linear measurement markings.

 

 

Fig : Measurement of pectoralis minor muscle

 

Data analysis:

Descriptive data analysis used to find pectoralis minor muscle shortening within each shoulder conditions. ANOVA used to compare the data of shortening between the shoulder conditions.

 

 

Table 1: Mean difference on Pectoralis minor muscle shortening between the conditions adhesive capsulitis, rounded shoulder, upper cross syndrome, fracture, shoulder subluxation and trapezitis.

Conditions	Mean	SD	SEM	95% Cl
				of Mean
Adhesive capsulitis	6.018	0.831	0.263	5.424 To 6.613
Rounded shoulder	6.499	0.598	0.189	6.071
				To 6.927
Upper cross syndrome	7.171	0.497	0.157	6.815 To 7.527
Fracture	6.938	0.556	0.176	6.540
				To 7.336
Shoulder dislocation	7.036	0.575	0.182	6.625 To 7.447
Trapezitis	6.938	0.536	0.170	6.412 To 7.180

 

The above table 1 shows Pectoralis minor muscle shortening is more on Adhesive capsulitis with mean value of 6.018, than other conditions of rounded shoulder, upper cross syndrome, fracture, shoulder subluxation and trapezitis mean values of 6.499, 7.171, 6.938, 7.036, 6.938 respectively. In fracture and shoulder dislocation the muscle shortening found same with mean value of 6.938.

Adhesive capsulitis mean value is (6.018), Standard Deviation (SD) is (0.831) and Standard Error of Measurement (SEM) is (0.263), the Confidence Interval (CI) mean value ranges between 5.424 and 6.613.

 

Rounded shoulder mean value is (6.499), Standard Deviation (SD) is (0.598) Standard Error of Measurement (SEM) is (0.189) and Confidence Interval mean value ranges between (6.071 to 6.927). Upper cross syndrome mean value is (7.171), Standard Deviation (SD) is (0.497), Standard Error of Measurement (SEM) is (0.157) and Confidence Intervals (CI) mean value ranges between 6.815 and 7.527). Fracture mean value is (6.938), Standard Deviation (SD) is (0.556), Standard Error of Measurement (SEM) is (0.176) and Confidence Interval (CI) value range between 6.540 and 7.336. Shoulder subluxation mean value is (7.036), Standard Deviation (SD) is (0.575), Standard Error of Measurement (SEM) is (0.182) and Confidence Interval (CI) mean value ranges between 6.625 and 7.447. Trapezitis mean value is (6.938), Standard Deviation (SD) is (0.536), Standard Error of Measurement (SEM) is (0.17) and Confidence Interval (CI) mean value ranges between 6.412and 7.18.

 

Table 2: ANOVA for compare Pectoralis minor muscle shortening between the conditions adhesive capsulitis, rounded shoulder, upper cross syndrome, fracture, shoulder subluxation and trapezitis.

Conditions	N	MS	SS	DF	F	P value	Significant Different (P < 0.05)
Adhesive capsulitis, Rounded shoulder, Upper cross syndrome, Fracture, Shoulder subluxation, Trapezitis	60	1.79	28.95	59	4.833	<0.001	****

 

The above table 2 shows significant Pectoralis minor muscle shortening between the conditions adhesive capsulitis, rounded shoulder, upper cross syndrome, fracture, shoulder subluxation and trapezitis with F value 4.958 and P<0.001.

 

The condition of Adhesive capsulitis, Rounded shoulder, Uppercross syndrome, Fracture, Shoulder subluxation, Trapezitis the Mean Square (MS) is (1.79), Sum Square (SS) is (28.95), Degree of Freedom (DF) is (59), F value is (4.833) and P value is P<0.001.

 

RESULTS:

Pectoralis minor muscle shortening found more on Adhesive capsulitis with mean value of 6.018, than other conditions of rounded shoulder, upper cross syndrome, fracture, shoulder subluxation and trapezit is with mean value of 6.499, 6.936, 7.036, and 6.938 respectively.

 

Pectoralis minor muscle shortening shows significant difference between the conditions; adhesive capsulitis, rounded shoulder, upper cross syndrome, fracture, shoulder subluxation and trapezitis with F value 4.832 and p <0.001.

 

DISCUSSION:

The present study was conducted to find the prevalence of pectoralis minor muscle shortening in pathological shoulder conditions. The study was conducted on 60 subjects with both males and females. Outcome measure is measuring tape which was measured the pectoralis minor muscle tightness. Pectoralis muscle tightness lead to tight and pain in the upper limb muscle and affect the posture

 

A study on shoulder pathology associated with DM shows reduced shoulder external rotation, humero-thoracic elevation and abduction. Movement restrictions in persons with diabetes are similar to those with idiopathic frozen shoulder, except without the excessive scapula-thoracic elevation and with fewer symptoms¹⁵.

 

In summary, functional impingement may be associated with muscle imbalance; therefore, careful examination of flexibility and strength of important muscles about the shoulder complex is vital to understanding the root cause of impingement and prescribing effective treatment. Janda's approach to muscle imbalance suggests a possible neuromuscular component to functional impingement due to the predisposition of certain muscles to be tight or weak^16,17.

 

The pectoralis minor shortening is associated with clinical syndromes, loss of function, pain and reduced movements in the shoulder and upper chest. The reports on researches shows pectoralis minor length test is a reliable method to measure the distance from the treatment table to the posterior aspect of the acromion. Patients without symptoms have recorded a mean length of approximately 6 cm, over a double recommended length of patients with symptoms^18,19.

 

The result shows that the pectoralis minor muscle shortening is more on Adhesive capsulitis with mean value of 6.018, than conditions of rounded shoulder, upper cross syndrome, fracture, shoulder subluxation and trapezitis mean value of 6.499, 936.7, 7.036, and 6.938 respectively. Pectoralis minor muscle shortening shows the significant between the conditions adhesive capsulitis, rounded shoulder, upper cross syndrome, fracture, shoulder subluxation and trapezitis with F value 4.958 and p<0.001.

 

Due to lack of adequate physical activity, muscle weakness, and some conditions adhesive capsulitis, rounded shoulder, upper cross syndrome, trapezitis, fracture and shoulder subluxation.

 

ETHICAL CLEARANCE:

Ethical clearance has obtained from the Institution to conduct this study with reference number: IV C-048/PHSIO/IRB/2017-18 dated 08/01/2018.

 

CONFLICT OF INTEREST:

There was no conflict of interest to conduct this study.

 

FUND FOR THIS STUDY:

Self .

 

CONCLUSION:

The study has concluded that there is a significant difference in pectoralis minor muscle shortening among patients with shoulder conditions. The analysis showed significant shortening of pectoralis minor muscle is more in adhesive capsulitis than the other conditions; rounded shoulder, fracture, shoulder subluxation and upper cross syndrome.

 

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Received on 08.04.2019           Modified on 10.06.2019

Accepted on 01.08.2019         © RJPT All right reserved