The coracoacromial ligament is a strong triangular

ligament A ligament is a type of fibrous connective tissue in the body that connects bones to other bones. It also connects flight feathers to bones, in dinosaurs and birds. All 30,000 species of amniotes (land animals with internal bones) have liga ...

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", : acromia) or summit of the shoulder is a bony process on the scapula (shoulder blade). Together with the coracoid process, it extends laterally over the sh ...

. It protects the head of the

humerus The humerus (; : humeri) 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 (bone), radius and ulna, and consists of three sections. The humeral upper extrem ...

. Its acromial attachment may be repositioned to the

clavicle The clavicle, collarbone, or keybone is a slender, S-shaped long bone approximately long that serves as a strut between the scapula, shoulder blade and the sternum (breastbone). There are two clavicles, one on each side of the body. The clavic ...

during

reconstructive surgery Reconstructive surgery is surgery performed to restore normal appearance and function to body parts malformed by a disease or medical condition. Description Reconstructive surgery is a term with training, clinical, and reimbursement implicat ...

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 joint, plane synovial joint ...

(shoulder joint).

Structure

The coracoacromial ligament originates from the summit of the

of the

scapula The scapula (: 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 either side ...

, just in front of the articular surface for the

. 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 shoulder, human shoulder. It is also known as the 'common shoulder muscle', particularly in other animals such as the domestic cat. Anatomically, the deltoid muscle is made up o ...

are above it. The tendon of the

supraspinatus muscle The supraspinatus (: 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 cuff mus ...

(and its

bursa Bursa () 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 Marmara Region, Bursa is one of the industrial centers of the country. Most of ...

) 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 infraspin ...

. 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. It arises from ribs III-V; it inserts onto the coracoid process of the scapula. It is innervated by ...

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 (SITS muscles) 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 a ...

muscle or tendon. It may be damaged during a shoulder injury. 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 is not part o ...

References

External links

{{Authority control Ligaments of the upper limb Scapula