Table of ContentsView All
View All
Table of Contents
Shoulder Bones
Shoulder Muscles
Shoulder Capsule
Shoulder Labrum
The shoulder joint is the articulation between the thorax and the arm. This joint is one of the most complex and mobile joints of the body as it is comprised of four articulations, plus muscles, tendons, and ligaments connecting the upper limb to the axial skeleton.
There are four joints which make up the shoulder joint and girdle:
Most shoulder motion occurs at the ball-and-socket glenohumeral joint. Still, for full motion and stability of the shoulder, the AC joint, SC joint, and scapulothoracic joint must also be functioning normally.
The three bones of the shoulder are the:
The scapula has one part that forms a socket for the head of the humerus, called the glenoid fossa. The glenoid fossa is covered with a smooth cartilage called the labrum. The rounded top of the arm bone (head of the humerus) contacts the glenoid fossa to make up the ball-and-socket articulation known as the glenohumeral joint.
The acromioclavicular joint is where a different part of the shoulder blade, the acromion, articulates to the distal or lateral portion of the collarbone (clavicle).
The socket of the shoulder joint is part of the scapula, and if scapular movement is not normal, then shoulder function cannot be normal. Many people with shoulder pain, weakness, and instability often need to focus on improvements in their scapular function to help improve their shoulder mechanics.
There are 17 muscles that cross the shoulder joint. Theperiscapularmuscles help to control the movements of the shoulder blade. This movement is critical to normal shoulder function.
Rotator Cuff
The rotator cuff is a group of four muscles and their tendons surrounding the glenohumeral joint controlling movements and providing stability. The muscles of the rotator cuff are the supraspinatus, infraspinatus, teres minor, and subscapularis.
The rotator cuff is important in many routine activities, and when it’s injured, it can cause severe pain. When the rotator cuff is inflamed or irritated, this is referred to as rotator cuff tendonitis. When the tendons of the rotator cuff have torn, this is called a rotator cuff tear.
Verywell / Alexandra Gordon
Rotator Cuff Tear: Warning Signs and the Healing Process
The shoulder capsule surrounds the ball-and-socket part of the shoulder joint. The capsule separates the joint from the rest of the body and contains the joint fluid.
Several ligaments make up parts of the joint capsule, and these ligaments are important in keeping the shoulder joint in the proper position. When the shoulder dislocates, the ligaments of the shoulder capsule can be torn.
The tension of the shoulder capsule is important:
Frozen Shoulder
The labrum is a rim of cartilage that surrounds the socket of the shoulder joint. The socket of the shoulder joint is shallow, and the labrum gives the socket more depth, and thus more stability. The labrum also serves as the attachment of a major tendon in the shoulder, the biceps tendon.
Labral tearsin the shoulder can cause pain, instability of the joint, or both.Labral tears are usually classified based on their location. The most common labral tears are those associated with a shoulder dislocation, called aBankart tear,and those associated with biceps tendon problems, calledSLAP tears.
What Is Shoulder Bursitis?
The shoulder joint is a very mobile joint and is capable of many types of movements in the planes of the body. These movements include:
6 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Miniato MA, Anand P, Varacallo M.Anatomy, shoulder and upper limb, shoulder. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024.Crowe MM, Elhassan BT.Scapular and shoulder girdle muscular anatomy: Its role in periscapular tendon transfers.J Hand Surg Am. 2016;41(2):306-315. doi:10.1016/j.jhsa.2015.06.123Ryan V, Brown H, Minns lowe CJ, Lewis JS.The pathophysiology associated with primary (idiopathic) frozen shoulder: A systematic review.BMC Musculoskelet Disord. 2016;17(1):340. doi:10.1186/s12891-016-1190-9Hospital for Special Surgery.Shoulder Labrum Tears: An Overview.Olds M, Ellis R, Donaldson K, Parmar P, Kersten P.Risk factors which predispose first-time traumatic anterior shoulder dislocations to recurrent instability in adults: a systematic review and meta-analysis.Br J Sports Med. 2015;49(14):913-922. doi: 10.1136/bjsports-2014-094342Simoni P, Scarciolla L, Kreutz J, Meunier B, Beomonte Zobel B.Imaging of superior labral anterior to posterior (Slap) tears of the shoulder.J Sports Med Phys Fitness. 2012;52(6):622-630. PMID: 23187325
6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Miniato MA, Anand P, Varacallo M.Anatomy, shoulder and upper limb, shoulder. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024.Crowe MM, Elhassan BT.Scapular and shoulder girdle muscular anatomy: Its role in periscapular tendon transfers.J Hand Surg Am. 2016;41(2):306-315. doi:10.1016/j.jhsa.2015.06.123Ryan V, Brown H, Minns lowe CJ, Lewis JS.The pathophysiology associated with primary (idiopathic) frozen shoulder: A systematic review.BMC Musculoskelet Disord. 2016;17(1):340. doi:10.1186/s12891-016-1190-9Hospital for Special Surgery.Shoulder Labrum Tears: An Overview.Olds M, Ellis R, Donaldson K, Parmar P, Kersten P.Risk factors which predispose first-time traumatic anterior shoulder dislocations to recurrent instability in adults: a systematic review and meta-analysis.Br J Sports Med. 2015;49(14):913-922. doi: 10.1136/bjsports-2014-094342Simoni P, Scarciolla L, Kreutz J, Meunier B, Beomonte Zobel B.Imaging of superior labral anterior to posterior (Slap) tears of the shoulder.J Sports Med Phys Fitness. 2012;52(6):622-630. PMID: 23187325
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Miniato MA, Anand P, Varacallo M.Anatomy, shoulder and upper limb, shoulder. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024.Crowe MM, Elhassan BT.Scapular and shoulder girdle muscular anatomy: Its role in periscapular tendon transfers.J Hand Surg Am. 2016;41(2):306-315. doi:10.1016/j.jhsa.2015.06.123Ryan V, Brown H, Minns lowe CJ, Lewis JS.The pathophysiology associated with primary (idiopathic) frozen shoulder: A systematic review.BMC Musculoskelet Disord. 2016;17(1):340. doi:10.1186/s12891-016-1190-9Hospital for Special Surgery.Shoulder Labrum Tears: An Overview.Olds M, Ellis R, Donaldson K, Parmar P, Kersten P.Risk factors which predispose first-time traumatic anterior shoulder dislocations to recurrent instability in adults: a systematic review and meta-analysis.Br J Sports Med. 2015;49(14):913-922. doi: 10.1136/bjsports-2014-094342Simoni P, Scarciolla L, Kreutz J, Meunier B, Beomonte Zobel B.Imaging of superior labral anterior to posterior (Slap) tears of the shoulder.J Sports Med Phys Fitness. 2012;52(6):622-630. PMID: 23187325
Miniato MA, Anand P, Varacallo M.Anatomy, shoulder and upper limb, shoulder. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024.
Crowe MM, Elhassan BT.Scapular and shoulder girdle muscular anatomy: Its role in periscapular tendon transfers.J Hand Surg Am. 2016;41(2):306-315. doi:10.1016/j.jhsa.2015.06.123
Ryan V, Brown H, Minns lowe CJ, Lewis JS.The pathophysiology associated with primary (idiopathic) frozen shoulder: A systematic review.BMC Musculoskelet Disord. 2016;17(1):340. doi:10.1186/s12891-016-1190-9
Hospital for Special Surgery.Shoulder Labrum Tears: An Overview.
Olds M, Ellis R, Donaldson K, Parmar P, Kersten P.Risk factors which predispose first-time traumatic anterior shoulder dislocations to recurrent instability in adults: a systematic review and meta-analysis.Br J Sports Med. 2015;49(14):913-922. doi: 10.1136/bjsports-2014-094342
Simoni P, Scarciolla L, Kreutz J, Meunier B, Beomonte Zobel B.Imaging of superior labral anterior to posterior (Slap) tears of the shoulder.J Sports Med Phys Fitness. 2012;52(6):622-630. PMID: 23187325
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