{"schemaVersion":1,"id":"en-pathway-shoulder-path","type":"pathway","pillar":"body","locale":"en","translationGroupId":"pathway-shoulder-path","slugPath":"pathways/the-shoulder-in-depth","title":"The shoulder in depth","shortTitle":"The shoulder","summary":"The most mobile joint in the body is also the one that holds least by its shape. Six steps to understand what follows from that, from the glenoid cavity to reaching overhead.","level":"intermediate","estimatedMinutes":55,"synonyms":["shoulder","shoulder complex","rotator cuff","shoulder blade","arm elevation","shoulder pathway"],"blocks":[{"id":"b1","type":"paragraph","content":[{"kind":"text","value":"The shoulder is the joint people talk about most and describe least well. The reason is a vocabulary problem: \"the shoulder\" names at least four linkages, one of which is not strictly a joint at all."}]},{"id":"b2","type":"paragraph","content":[{"kind":"text","value":"This pathway puts them in the order they come into play, from the bony surface to the arm raised overhead."}]},{"id":"b3","type":"heading","level":2,"text":"What this pathway lets you understand","anchor":"what-this-pathway-lets-you-understand"},{"id":"b4","type":"paragraph","content":[{"kind":"text","value":"One idea runs through it: "},{"kind":"strong","value":"the shoulder trades stability for range"},{"kind":"text","value":", and everything else follows. The shape of the socket, the role of the labrum, the presence of four short muscles that move almost nothing, the need for the shoulder blade to move too."}]},{"id":"b5","type":"paragraph","content":[{"kind":"text","value":"By the end, raising the arm should read as a coordination rather than the action of one muscle."}]},{"id":"b6","type":"heading","level":2,"text":"Level, prerequisites and reading time","anchor":"level-prerequisites-and-reading-time"},{"id":"b7","type":"paragraph","content":[{"kind":"text","value":"The "},{"kind":"link","value":"Locate and name","href":"/en/pathways/locate-and-name","external":false},{"kind":"text","value":" pathway helps without being compulsory. Allow around fifty-five minutes."}]},{"id":"b8","type":"heading","level":2,"text":"The steps of the pathway","anchor":"the-steps-of-the-pathway"},{"id":"b9","type":"stepList","title":"The six steps, in order","steps":[{"id":"e1","title":"The shape of the problem","summary":"Four linkages under one word, a shallow socket and a wide head: where the range comes from, and what it costs.","targetId":"en-anatomy-shoulder-joint","estimatedMinutes":8},{"id":"e2","title":"What centres the bone","summary":"The four cuff muscles. Their job is not to move the arm but to hold its head in place while it moves.","targetId":"en-anatomy-rotator-cuff","estimatedMinutes":9},{"id":"e3","title":"What moves the arm","summary":"The deltoid and its three parts, supplying the force the cuff makes possible.","targetId":"en-anatomy-deltoids","estimatedMinutes":8},{"id":"e4","title":"What orients the socket","summary":"Serratus anterior rotates the shoulder blade: without it, the arm does not fully rise.","targetId":"en-anatomy-serratus-anterior","estimatedMinutes":8},{"id":"e5","title":"The serratus's partner","summary":"The trapezius completes the rotation of the shoulder blade. The two form a force couple around it.","targetId":"en-anatomy-trapezius","estimatedMinutes":9},{"id":"e6","title":"The complete movement","summary":"The vertical push, where these four players coordinate to bring a load overhead.","targetId":"en-movement-vertical-push","estimatedMinutes":8}]},{"id":"b10","type":"heading","level":2,"text":"What to take away","anchor":"what-to-take-away"},{"id":"b11","type":"paragraph","content":[{"kind":"text","value":"Raising the arm is not a shoulder movement in the narrow sense. Roughly a third of the range comes from rotation of the shoulder blade on the ribcage, produced by "},{"kind":"link","value":"serratus anterior","href":"/en/body/muscles/serratus-anterior","external":false},{"kind":"text","value":" and the "},{"kind":"link","value":"trapezius","href":"/en/body/muscles/trapezius","external":false},{"kind":"text","value":". The glenohumeral joint supplies the rest."}]},{"id":"b12","type":"evidence","level":"established","statement":"Full arm elevation combines movement at the glenohumeral joint with rotation of the shoulder blade on the ribcage.","detail":"Descriptive anatomy and kinesiology describe this coordination in converging terms. The exact proportion attributable to each varies with the measurement method and the range considered, and published values differ between research groups.","referenceIds":["standring2020","neumann2016"]},{"id":"b13","type":"paragraph","content":[{"kind":"text","value":"Second point: the rotator cuff is not judged by the force it produces. Its work is centring, and it is noticed mostly when it is missing."}]},{"id":"b14","type":"evidence","level":"probable","statement":"Shoulder characteristics differ in people who regularly do resistance training.","detail":"The study describes differences in range and in muscle characteristics in a population of recreational lifters. It is an observation on a group: it establishes no cause and effect and supports no conclusion about any particular person.","referenceIds":["kolber2009"]},{"id":"b15","type":"callout","tone":"insight","title":"The thread to keep","content":[[{"kind":"text","value":"A poorly fitted joint delegates its stability to muscles. That is true at the shoulder and false at the "},{"kind":"link","value":"hip","href":"/en/body/joints/hip","external":false},{"kind":"text","value":", which holds by its shape and lets its ligaments do the work when standing."}],[{"kind":"text","value":"Comparing the two is the fastest way to understand either."}]]},{"id":"b16","type":"heading","level":2,"text":"Checking what stuck","anchor":"checking-what-stuck"},{"id":"b17","type":"quiz","title":"Check my understanding","questions":[{"id":"q1","prompt":"What exactly does the word \"shoulder\" name?","choices":[{"id":"q1c1","label":"A set of at least four linkages","correct":true,"explanation":"Glenohumeral, acromioclavicular, sternoclavicular, and the gliding of the shoulder blade on the ribcage."},{"id":"q1c2","label":"The joint between humerus and shoulder blade","correct":false,"explanation":"That is the main one, but it supplies only part of the arm's range."},{"id":"q1c3","label":"The joint between collarbone and breastbone","correct":false,"explanation":"That is the only bony attachment to the trunk, not the whole shoulder."}]},{"id":"q2","prompt":"What is the main role of the rotator cuff?","choices":[{"id":"q2c1","label":"Keeping the humeral head centred during movement","correct":true,"explanation":"The four muscles pull the humerus towards the socket and hold it there while the large muscles move the arm."},{"id":"q2c2","label":"Producing the force of arm elevation","correct":false,"explanation":"That is the deltoid's role. Supraspinatus only starts the first few degrees."},{"id":"q2c3","label":"Limiting rotation of the shoulder blade","correct":false,"explanation":"The blade is oriented by serratus anterior and the trapezius, not by the cuff."}]},{"id":"q3","prompt":"Why does a failing serratus anterior limit arm elevation?","choices":[{"id":"q3c1","label":"Because the shoulder blade no longer rotates enough","correct":true,"explanation":"Roughly a third of the range comes from rotation of the blade, which this muscle produces."},{"id":"q3c2","label":"Because the deltoid loses strength","correct":false,"explanation":"The deltoid is unaffected; what is missing is the orientation of the socket."},{"id":"q3c3","label":"Because the joint capsule tightens","correct":false,"explanation":"The capsule plays no part in this mechanism."}]}]},{"id":"b18","type":"heading","level":2,"text":"Sources","anchor":"sources"},{"id":"b19","type":"sourceList","title":"Sources for this pathway","referenceIds":["standring2020","neumann2016","kolber2009"]},{"id":"b20","type":"relatedContent","title":"Read next","targetIds":["en-pathway-movement-path","en-anatomy-hip-joint","en-movement-vertical-pull"]},{"id":"b21","type":"shapierAction","actionId":"exercise-developpe-epaules","label":"Practise the shoulder press","description":"Setting up the shoulder press and tracking progression happen in Shapier; Body Lab only explains what this movement asks of the shoulder complex.","webTarget":"https://shapier.app/en/exercises/developpe-epaules","appTarget":"shapier://exercises/developpe-epaules"}],"relations":[{"type":"prerequisite","targetId":"en-pathway-body-map-path"},{"type":"explains","targetId":"en-anatomy-shoulder-joint"},{"type":"next-step","targetId":"en-pathway-movement-path"},{"type":"shapier-action","targetId":"exercises-by-muscle"}],"authors":["equipe-editoriale-shapier"],"reviewers":["Thanh Chau"],"references":[{"id":"standring2020","authors":"Standring S","year":2020,"title":"Gray's Anatomy: The Anatomical Basis of Clinical Practice, 42nd edition","source":"Elsevier","kind":"book","url":"https://shop.elsevier.com/books/grays-anatomy/standring/978-0-7020-7705-0"},{"id":"neumann2016","authors":"Neumann DA","year":2016,"title":"Kinesiology of the Musculoskeletal System: Foundations for Rehabilitation, 3rd edition","source":"Elsevier","kind":"book","url":"https://shop.elsevier.com/books/kinesiology-of-the-musculoskeletal-system/neumann/978-0-323-28753-1"},{"id":"kolber2009","authors":"Kolber MJ, Beekhuizen KS, Cheng MS, Hellman MA","year":2009,"title":"Shoulder joint and muscle characteristics in the recreational weight training population","source":"Journal of Strength and Conditioning Research","kind":"journal-article","doi":"10.1519/jsc.0b013e31818eafb4"}],"review":{"publishedAt":"2026-08-02","reviewedAt":"2026-08-02","reviewDueAt":"2027-08-02","evidenceLevel":"established"},"limitations":["The pathway describes a reference anatomy: the depth of the glenoid cavity and the shape of the acromion vary between people.","Shoulder pain is a frequent reason for consultation with many possible causes. No step allows discomfort to be attributed to a structure: this pathway explains a mechanism, it diagnoses nothing.","The 3D models represent neither cartilage nor the bursae, including the subacromial bursa, which is central to many discussions about the shoulder."],"seo":{"title":"The shoulder in depth — a guided pathway through the shoulder complex","description":"Six steps from the glenoid cavity to reaching overhead: labrum, rotator cuff, serratus, deltoid, and the role of the shoulder blade.","canonicalPath":"/en/pathways/the-shoulder-in-depth","image":"/og/en/pathway-shoulder-path.png"},"app":{"offlineEligible":true},"version":1}