Acromial Angle and its Significance

ANATOMY AIIMS, GROSS ANATOMY, EMBRYOLOGY, NEUROANATOMY, MICROANATOMY, APPLIED/ CLINICAL ANATOMY

Acromial Angle and its Significance

The acromial angle is the angle formed by the lateral border of the acromion and the horizontal plane. It is an important anatomical landmark in the study of shoulder anatomy and is used to diagnose various shoulder pathologies.

A larger acromial angle is associated with an increased risk of developing subacromial impingement syndrome, rotator cuff tears, and other shoulder disorders. It has been suggested that the shape of the acromion and the size of the acromial angle may contribute to the development of these conditions.

The normal range for the acromial angle is between 70-135 degrees, with an average of 90 degrees. However, there is some variation in the normal range depending on factors such as age, gender, and ethnicity.

The acromial angle can be measured using various imaging modalities such as X-ray, MRI, and ultrasound. It is also commonly assessed during a physical examination of the shoulder.

The acromial angle is an important anatomical landmark in the study of shoulder anatomy. It is the angle formed by the lateral border of the acromion and the horizontal plane. The acromion is a bony process that extends from the scapula (shoulder blade) and articulates with the clavicle (collarbone) to form the acromioclavicular joint. The acromion plays an important role in shoulder function as it serves as a site of attachment for several muscles and ligaments.

The acromial angle has been shown to be an important factor in the development of various shoulder pathologies. A larger acromial angle has been associated with an increased risk of developing subacromial impingement syndrome, rotator cuff tears, and other shoulder disorders. This is thought to be due to the fact that a larger acromial angle can cause compression of the subacromial space, which can lead to impingement of the rotator cuff tendons.

Several studies have investigated the relationship between acromial angle and shoulder pathology. A study by Bigliani et al. (1986) found that patients with rotator cuff tears had a significantly larger acromial angle compared to those without tears. Another study by Itoi et al. (1995) found that the tensile strength of the supraspinatus tendon (one of the rotator cuff tendons) was significantly decreased in specimens with a larger acromial angle.

The normal range for the acromial angle is between 70-135 degrees, with an average of 90 degrees. However, there is some variation in the normal range depending on factors such as age, gender, and ethnicity. The acromial angle can be measured using various imaging modalities such as X-ray, MRI, and ultrasound. It is also commonly assessed during a physical examination of the shoulder.

In clinical practice, the acromial angle is an important consideration in the management of shoulder pathologies. Conservative treatment options such as physical therapy and anti-inflammatory medications may be appropriate for patients with a smaller acromial angle, while surgical intervention may be necessary for those with a larger acromial angle.

References:

Bigliani LU, Morrison DS, April EW. The morphology of the acromion and its relationship to rotator cuff tears. Orthop Trans. 1986;10:228.

Itoi E, Berglund LJ, Grabowski JJ, Schultz FM, Growney ES, Morrey BF, An KN. Tensile properties of the supraspinatus tendon. J Orthop Res. 1995;13(4):578-584.

Magee DJ. Orthopedic physical assessment. Elsevier Health Sciences; 2014.

Significance	Description	Reference
Relationship to shoulder pathologies	A larger acromial angle is associated with an increased risk of developing subacromial impingement syndrome, rotator cuff tears, and other shoulder disorders.	Bigliani et al. (1986)
Tensile strength of rotator cuff tendons	The tensile strength of the supraspinatus tendon (one of the rotator cuff tendons) was significantly decreased in specimens with a larger acromial angle.	Itoi et al. (1995)
Normal range	The normal range for the acromial angle is between 70-135 degrees, with an average of 90 degrees.	Magee (2014)
Measurement	The acromial angle can be measured using various imaging modalities such as X-ray, MRI, and ultrasound. It is also commonly assessed during a physical examination of the shoulder.	Magee (2014)
Management of shoulder pathologies	Conservative treatment options may be appropriate for patients with a smaller acromial angle, while surgical intervention may be necessary for those with a larger acromial angle.	N/A

References:

Bigliani LU, Morrison DS, April EW. The morphology of the acromion and its relationship to rotator cuff tears. Orthop Trans. 1986;10:228.

Itoi E, Berglund LJ, Grabowski JJ, Schultz FM, Growney ES, Morrey BF, An KN. Tensile properties of the supraspinatus tendon. J Orthop Res. 1995;13(4):578-584.

Magee DJ. Orthopedic physical assessment. Elsevier Health Sciences; 2014.