The coracoacromial ligament is a strong triangular

ligament A ligament is the fibrous connective tissue that connects bones to other bones. It is also known as ''articular ligament'', ''articular larua'', ''fibrous ligament'', or ''true ligament''. Other ligaments in the body include the: * Peritoneal li ...

between the

coracoid process The coracoid process (from Greek κόραξ, raven) is a small hook-like structure on the lateral edge of the superior anterior portion of the scapula (hence: coracoid, or "like a raven's beak"). Pointing laterally forward, it, together with the ...

and the

acromion In human anatomy, the acromion (from Greek: ''akros'', "highest", ''ōmos'', "shoulder", plural: acromia) is a bony process on the scapula (shoulder blade). Together with the coracoid process it extends laterally over the shoulder joint. The acro ...

. It protects the head of the

humerus The humerus (; ) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of a roun ...

. Its acromial attachment may be repositioned to the clavicle during reconstructive surgery of the

acromioclavicular joint The acromioclavicular joint, or AC joint, is a joint at the top of the shoulder. It is the junction between the acromion (part of the scapula that forms the highest point of the shoulder) and the clavicle. It is a plane synovial joint. Structure ...

(shoulder joint).

Structure

The coracoacromial ligament originates from the summit of the

of the

scapula The scapula (plural scapulae or scapulas), also known as the shoulder blade, is the bone that connects the humerus (upper arm bone) with the clavicle (collar bone). Like their connected bones, the scapulae are paired, with each scapula on eithe ...

, just in front of the articular surface for the

clavicle The clavicle, or collarbone, is a slender, S-shaped long bone approximately 6 inches (15 cm) long that serves as a strut between the shoulder blade and the sternum (breastbone). There are two clavicles, one on the left and one on the rig ...

. It inserts by its broad base along the whole length of the lateral border of the

of the scapula. The clavicle and under surface of the

deltoid muscle The deltoid muscle is the muscle forming the rounded contour of the human shoulder. It is also known as the 'common shoulder muscle', particularly in other animals such as the domestic cat. Anatomically, the deltoid muscle appears to be made up o ...

are above it. The tendon of the

supraspinatus muscle The supraspinatus (plural ''supraspinati'') is a relatively small muscle of the upper back that runs from the supraspinous fossa superior portion of the scapula (shoulder blade) to the greater tubercle of the humerus. It is one of the four rotator ...

(and its

bursa ( grc-gre, Προῦσα, Proûsa, Latin: Prusa, ota, بورسه, Arabic:بورصة) is a city in northwestern Turkey and the administrative center of Bursa Province. The fourth-most populous city in Turkey and second-most populous in the ...

) are below it. Its lateral border is continuous with a dense lamina that passes beneath the

upon the tendons of the supraspinatus and

infraspinatus muscle In human anatomy, the infraspinatus muscle is a thick triangular muscle, which occupies the chief part of the infraspinatous fossa.'' Gray's Anatomy'', see infobox. As one of the four muscles of the rotator cuff, the main function of the infraspi ...

. The ligament is sometimes described as consisting of two marginal bands and a thinner intervening portion, the two bands being attached respectively to the apex and the base of the coracoid process, and joining at the acromion. When the

pectoralis minor Pectoralis minor muscle () is a thin, triangular muscle, situated at the upper part of the chest, beneath the pectoralis major in the human body. Structure Attachments Pectoralis minor muscle arises from the upper margins and outer surfaces ...

is inserted, as occasionally is the case, into the capsule of the

shoulder-joint The shoulder joint (or glenohumeral joint from Greek ''glene'', eyeball, + -''oid'', 'form of', + Latin ''humerus'', shoulder) is structurally classified as a synovial ball-and-socket joint and functionally as a diarthrosis and multiaxial joint. ...

instead of into the coracoid process, it passes between these two bands, and the intervening portion of the ligament is then deficient.

Function

Together with the

and the

, the coracoacromial ligament forms a vault or arch that protects the head of the

Clinical significance

The coracoacromial ligament may impinge and compress

rotator cuff The rotator cuff is a group of muscles and their tendons that act to stabilize the human shoulder and allow for its extensive range of motion. Of the seven scapulohumeral muscles, four make up the rotator cuff. The four muscles are the supraspi ...

muscle or tendon. It may be damaged during a

shoulder injury Shoulder problems including pain, are one of the more common reasons for physician visits for musculoskeletal symptoms. The shoulder is the most movable joint in the body. However, it is an unstable joint because of the range of motion allowed. ...

. The attachment of the coracoacromial ligament may be moved from

to the end of the

when reconstructing the

. This often fails. It has lower strength than the

coracoclavicular ligament The coracoclavicular ligament is a ligament of the shoulder. It connects the clavicle to the coracoid process of the scapula. Structure The coracoclavicular ligament connects the clavicle to the coracoid process of the scapula. It it is not par ...

References

External links

{{Authority control Ligaments of the upper limb Scapula