| Bone: Acromion | |
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| Plan of ossification of the scapula. Posterior side. From seven centers. (Acromion visible at upper left, in blue.) | |
| Left scapula. Lateral view. (Acromion labeled at upper right.) | |
| Gray's | subject #50 203 |
The acromion process, or simply the acromion (from Greek: akros, "highest", ōmos, "shoulder"), is an anatomical feature on the shoulder blade (scapula), together with the coracoid process extending laterally over the shoulder joint.
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It is a continuation of the scapular spine, and hooks over anteriorly.
The acromion articulates with the clavicle to form the acromioclavicular joint.
The acromion forms the summit of the shoulder, and is a large, somewhat triangular or oblong process, flattened from behind forward, projecting at first lateralward, and then curving forward and upward, so as to overhang the glenoid cavity.
In childhood the acromion has a separate center of ossification and is joined to the rest of the scapula by cartilage. Rarely, the acromion stays in adulthood as a separate bone called "os acromiale". This feature was common in skeletons recovered from the Mary Rose shipwreck: it is thought that in those men, much archery practice from childhood on with the mediaeval war bow (which needs a pull 3 times as strong as the modern standard Olympic bow) pulled at the acromion so much that it prevented bony fusion of the acromion with the scapula.
The acromion process of bats (Mammalia: Chiroptera) is particularly elongated compared to that of humans. Turtles (Reptilia: Testudinata) have an acromion that forms the anteriormost of the three "branches" of their triradiate pectoral girdle (together with coracoid bone and scapula).
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This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.