Acromial types
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View Frank Gaillard's current disclosuresAt the time the article was last revised Mohammad Taghi Niknejad had no financial relationships to ineligible companies to disclose.
View Mohammad Taghi Niknejad's current disclosures- Acromion types
- Types of the acromion
- Bigliani classification of acromion types
- Bigliani classification of acromion morphology
- Bigliani classification
Acromial types were initially divided into three types (known as the Bigliani classification) 3, to which a fourth has been added 2. These classifications are used as a standardised way of describing the acromion and predicting to a degree the incidence of impingement.
Classification
This classification was initially proposed by Bigliani et al. in 1986 on outlet view radiographs and later modified by Kitay et al. 7 and Vanarthos et al. in 1995, which remains the most widely accepted classification at the time of writing (2022).
Acromial morphology is variable on sagittal oblique MRI, depending on the slice position. A slice position just lateral to the acromioclavicular joint (no joint capsule or acromioclavicular ligament visible) is considered the single best slice 8.
Acromion morphology (types) are based on sagittal oblique MRI:
flat inferiorly (12%) 6
-
curved (56%)
parallel to the humeral head with a concave undersurface
down-sloping in the middle-third of the acromion 8
considered the most common type 3
-
hooked (29%)
most anterior portion of the acromion has a hooked shape
down-sloping in the anterior-third of the acromion 8
associated with increased incidence of shoulder impingement
-
convex (upturned) (3%)
most recent classification of acromion process shape
the undersurface of the acromion is convex near the distal end 4
no convincing correlation between a type 4 acromion and impingement syndrome exists 4,5
See also
References
- 1. Phoebe Kaplan. Musculoskeletal MRI. (2001) ISBN: 0721690270 - Google Books
- 2. Vanarthos W & Monu J. Type 4 Acromion: A New Classification. Contemp Orthop. 1995;30(3):227-9. - Pubmed
- 3. Getz J, Recht M, Piraino D et al. Acromial Morphology: Relation to Sex, Age, Symmetry, and Subacromial Enthesophytes. Radiology. 1996;199(3):737-42. doi:10.1148/radiology.199.3.8637998
- 4. Chang E, Moses D, Babb J, Schweitzer M. Shoulder Impingement: Objective 3D Shape Analysis of Acromial Morphologic Features. Radiology. 2006;239(2):497-505. doi:10.1148/radiol.2392050324 - Pubmed
- 5. Haaga, John R. 1945-. CT and MR Imaging of the Whole Body. (2009) ISBN: 9780323053754 - Google Books
- 6. Mulyadi E, Harish S, O'Neill J, Rebello R. MRI of Impingement Syndromes of the Shoulder. Clin Radiol. 2009;64(3):307-18. doi:10.1016/j.crad.2008.08.013
- 7. Kitay G, Iannotti J, Williams G, Haygood T, Kneeland B, Berlin J. Roentgenographic Assessment of Acromial Morphologic Condition in Rotator Cuff Impingement Syndrome. J Shoulder Elbow Surg. 1995;4(6):441-8. doi:10.1016/s1058-2746(05)80036-9
- 8. Mayerhoefer M, Breitenseher M, Roposch A, Treitl C, Wurnig C. Comparison of MRI and Conventional Radiography for Assessment of Acromial Shape. AJR Am J Roentgenol. 2005;184(2):671-5. doi:10.2214/ajr.184.2.01840671 - Pubmed
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- Bifid biceps tendon
- Os acromiale
- Adhesive capsulitis of the shoulder
- Bigliani type 2 acromion
- Bifid biceps tendon
- Acromial fracture
- Bifid biceps tendon
- Acromial fracture
- Hill-Sachs and osseous Bankart lesions
- Bifid biceps tendon
- Supraspinatus tendinosis
- Subacromial Impingement
- Reverse Bankart lesion
- Bigliani type 3 acromion
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- Acromial types
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