Subscapularis
Shoulder & Scapula · Upper Limb
Subscapularis belongs to the Shoulder & Scapula group of the Upper Limb. It arises from Subscapular fossa (costal surface of scapula) and attaches to Lesser tubercle of humerus. It is responsible for several movements: Medial (internal) rotation of arm; stabilizes glenohumeral joint. Its nerve supply is the Upper and lower subscapular nerves (C5, C6).
Origin, Insertion, Action & Nerve
Origin
Subscapular fossa (costal surface of scapula)
Insertion
Lesser tubercle of humerus
Action
Medial (internal) rotation of arm; stabilizes glenohumeral joint
Nerve
Upper and lower subscapular nerves (C5, C6)
Attachments explained
The Subscapularis is defined first by where it attaches. Its origin is the more fixed anchor, usually the proximal or more stable end that stays put during contraction, while its insertion is the more mobile point that is pulled toward the origin when the muscle shortens.
Origin
Subscapular fossa (costal surface of scapula)
Insertion
Lesser tubercle of humerus
Action & function
When the Subscapularis contracts, it produces the following movements: Medial (internal) rotation of arm; stabilizes glenohumeral joint.
As part of the Shoulder & Scapula group of the Upper Limb, it works alongside neighbouring muscles to generate smooth, coordinated movement and to stabilise the structures it acts on.
Nerve supply & clinical relevance
The Subscapularis receives its nerve supply from the Upper and lower subscapular nerves (C5, C6). This nerve carries fibres from spinal segment(s) C5, C6.
Because a muscle can only contract when its nerve is intact, injury to the Upper and lower subscapular nerves or to its spinal roots (C5, C6) can weaken or paralyse the Subscapularis, impairing the movements it normally produces (medial (internal) rotation of arm). This is why knowing the innervation is central to localising nerve lesions in clinical practice.
How to study the Subscapularis (the OIANS method)
OIANS stands for Origin, Insertion, Action and Nerve, the four facts that uniquely define every skeletal muscle. To learn the Subscapularis, work through them in order: picture its origin, trace the muscle to its insertion, reason out the action that shortening between those two points must create, then add the nerve that drives it.
Most students remember the Subscapularis fastest by linking its action back to its attachments rather than memorising each fact in isolation. Once the origin and insertion make sense, the action usually follows logically.
Subscapularis quick facts
- Region
- Upper Limb
- Group
- Shoulder & Scapula
- Origin
- Subscapular fossa (costal surface of scapula)
- Insertion
- Lesser tubercle of humerus
- Action
- Medial (internal) rotation of arm; stabilizes glenohumeral joint
- Nerve
- Upper and lower subscapular nerves (C5, C6)
- Spinal roots
- C5, C6
Frequently asked questions
Where is the Subscapularis located?
The Subscapularis is a muscle of the Shoulder & Scapula group, located in the Upper Limb.
What is the origin of the Subscapularis?
Subscapular fossa (costal surface of scapula)
What is the insertion of the Subscapularis?
Lesser tubercle of humerus
What movements does the Subscapularis produce?
Medial (internal) rotation of arm; stabilizes glenohumeral joint
What nerve supplies the Subscapularis?
Upper and lower subscapular nerves (C5, C6)
Is the Subscapularis free to study in OIANS?
Yes. The Subscapularis is free in OIANS: its full origin, insertion, action and nerve details are open to everyone in the Muscle Directory, and because it belongs to the Upper Limb it is also covered by the free Quiz and Flashcard decks. The other regions, the "All Muscles" deck, and the Progress and Explore tools are unlocked with a one-time Lifetime purchase.
Related muscles
Study the Subscapularis
Test yourself on Upper Limb muscles with interactive quizzes and flashcards in the free OIANS app.
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