Greater Tubercle
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The greater tubercle 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 ...
is the outward part the upper end of that bone, adjacent to the large rounded prominence of the humerus head. It provides attachment points for the
supraspinatus 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 m ...
, infraspinatus, and teres minor muscles, three of the four muscles of the
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 ...
, a muscle group that stabilizes 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 joint, synovial ball-and-socket joint and functionally as a diarthrosis and m ...
. In doing so the tubercle acts as a location for the transfer of
forces In physics, a force is an influence that can cause an object to change its velocity unless counterbalanced by other forces. In mechanics, force makes ideas like 'pushing' or 'pulling' mathematically precise. Because the magnitude and directi ...
from the rotator cuff muscles to the humerus.


Structure

The upper surface of the greater tubercle is rounded, and marked by three flat impressions: * the highest ("superior facet") gives insertion to the supraspinatus muscle. * the middle ("middle facet") gives insertion to the infraspinatus muscle. * the lowest ("inferior facet"), and the body of the bone for about 2.5  cm, gives insertion to the teres minor muscle. The lateral surface of the greater tubercle is convex, rough, and continuous with the lateral surface of the body 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 ...
. It can be described as having a cranial and a caudal part. Between the greater tubercle and the
lesser tubercle The lesser tubercle 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 thre ...
is the bicipital groove (intertubercular sulcus).


Function

All three of the muscles that attach to the greater tubercle are part of the
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 ...
, a muscle group that stabilizes 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 joint, synovial ball-and-socket joint and functionally as a diarthrosis and m ...
. The greater tubercle therefore acts as a location for the transfer of
forces In physics, a force is an influence that can cause an object to change its velocity unless counterbalanced by other forces. In mechanics, force makes ideas like 'pushing' or 'pulling' mathematically precise. Because the magnitude and directi ...
from the rotator cuff muscles to the humerus. The fourth muscle of the rotator cuff (
subscapularis muscle The subscapularis is a large triangular muscle which fills the subscapular fossa and inserts into the lesser tubercle of the humerus and the front of the capsule of the shoulder-joint. Structure The subscapularis is covered by a dense fasci ...
) does not attach to the greater tubercle, but instead attaches to the
lesser tubercle The lesser tubercle 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 thre ...
.


Clinical significance

The greater tubercle is usually the easiest part of the humerus to palpate. It can be a useful surface landmark during
surgery Surgery is a medical specialty that uses manual and instrumental techniques to diagnose or treat pathological conditions (e.g., trauma, disease, injury, malignancy), to alter bodily functions (e.g., malabsorption created by bariatric surgery s ...
.


Additional images

File:Human arm bones diagram.svg, Human arm bones diagram


References


External links

* * * * {{Authority control Bones of the upper limb Humerus