Clavicle (collarbone)The collarbone, which meets the acromion at its outer end. That small joint, the acromioclavicular joint, lies above the shoulder joint itself.
Scapula (shoulder blade)The shoulder blade, with the socket on its outer corner. The acromion and the coracoid process both grow from it.
Humerus (upper arm bone)The bone of the upper arm. The ball at its top fits the socket on the shoulder blade, which makes the shoulder a ball and socket joint.
AcromionA flat process of the shoulder blade that overhangs the joint. It forms the summit of the shoulder, and the collarbone joins it.
Coracoid processA hook of bone pointing forward from the shoulder blade. Three of the ligaments on the next drawing start on it.
Head of the humerusThe smooth ball that sits in the socket. It is much larger than the socket, which lets the arm move widely.
Capsule and ligaments 9
Joint capsuleA loose sleeve of fibrous tissue round the whole joint. It runs from the rim of the socket to the neck of the humerus, and its slack lets the arm swing freely.
Glenohumeral ligamentsThree bands that strengthen the front of the capsule. The superior, middle and inferior bands run from the rim of the socket to the humerus.
Coracohumeral ligamentA band that supports the top of the capsule. It runs from the coracoid process's base to the humerus's greater tubercle.
Coracoacromial ligamentA band between the coracoid process and the acromion. With those two it makes an arch over the joint that stops the ball riding upward.
Acromioclavicular ligamentA band across the top of the small acromioclavicular joint. It runs from the acromion to the outer end of the collarbone.
Coracoclavicular ligamentTwo strong parts, the conoid and the trapezoid ligaments. They run from the coracoid process up to the collarbone and hang the weight of the arm from it.
Transverse humeral ligamentA band between the humerus's two tubercles. It holds the biceps tendon in the groove between them.
Tendon of the long head of the bicepsIt starts at the top of the rim of the socket. It runs through the joint and leaves between the two tubercles to go down the arm.
Subacromial bursaA thin sac of fluid under the acromion and the deltoid. It lies on the supraspinatus tendon and cuts friction as the arm moves.
The socket and rotator cuff 6
Glenoid cavityThe shallow socket on the shoulder blade, facing the humerus. The head of the humerus sits against it, and both are covered with smooth cartilage.
Glenoid labrumA rim of fibrocartilage fixed round the edge of the socket. It deepens the socket and helps seal it against the ball.
Supraspinatus tendonThe top tendon of the rotator cuff. It crosses over the joint under the acromion and ends on the greater tubercle, joined to the capsule.
Infraspinatus tendonA rotator cuff tendon behind the joint. It crosses the back of the capsule and ends on the greater tubercle, below the supraspinatus.
Teres minor tendonThe lowest of the rotator cuff tendons behind the joint. It ends on the greater tubercle, below the infraspinatus.
Subscapularis tendonThe rotator cuff tendon in front of the joint. It ends on the lesser tubercle of the humerus and on the front of the capsule.
How this list was compiled: Every name and detail line was checked on 2026-09-30 against TeachMeAnatomy, The Shoulder Joint, https://teachmeanatomy.info/upper-limb/joints/shoulder/, and The Acromioclavicular Joint, https://teachmeanatomy.info/upper-limb/joints/acromioclavicular/; Gray, Anatomy of the Human Body, 20th edition, 1918 (public domain), the sections on the scapula, the shoulder joint and the muscles of the shoulder, https://archive.org/details/anatomyofhumanbo00grayrich; and Kenhub, Glenohumeral joint, https://www.kenhub.com/en/library/anatomy/the-shoulder-joint. The wording is in our own words. Licence: own work
The drawing: Drawn for this site on 2026-09-30 from plain geometry; nothing traced. Licence: own work
How it works
A right shoulder drawn three times: the bones alone, the same view with the capsule and ligaments on, and the socket from the side with the arm bone lifted away. Twenty-one parts to find and name.
Read the full guide
Bones first, then what ties them
The ball on the humerus meets a shallow socket on the shoulder blade. A loose capsule wraps the two, with the three glenohumeral ligaments on its front. The other ligaments run between the coracoid process, the acromion, the collarbone and the humerus, and each is named for the two bones it joins.
The socket from the side
With the arm bone away, the glenoid cavity shows as a pear shape with the labrum round its edge. Four tendons hug it: supraspinatus above, infraspinatus and teres minor behind, subscapularis in front. Together they are the rotator cuff.
Read a ligament name as two bones: coraco-acromial runs from the coracoid process to the acromion.
Only one rotator cuff tendon lies in front of the joint: the subscapularis.
Questions and answers
What are the parts of a shoulder?
Three bones, the collarbone, the shoulder blade and the humerus; the ball and socket joint between the last two; a loose capsule and its ligaments; the labrum round the socket; the four rotator cuff tendons; and a bursa under the acromion.
What is the rotator cuff?
Four muscles whose tendons surround the shoulder joint and blend with its capsule: supraspinatus, infraspinatus, teres minor and subscapularis. They hold the head of the humerus against the socket while larger muscles move the arm.
What does the glenoid labrum do?
It is a rim of fibrocartilage fixed round the edge of the glenoid cavity. The socket is much smaller than the ball of the humerus, and the labrum deepens it and helps seal the two together.
Which ligaments hold the collarbone to the shoulder blade?
The acromioclavicular ligament, across the top of the small joint with the acromion, and the much stronger coracoclavicular ligament, whose conoid and trapezoid parts run from the coracoid process up to the collarbone.