The upper limb sacrifices some stability for exceptional mobility. Its joints form a linked chain from the sternum to the fingertips: sternoclavicular, acromioclavicular, scapulothoracic, glenohumeral, elbow, radioulnar, wrist and hand joints. Understanding each joint’s surfaces, capsule, ligaments, movement and stability helps the physiotherapist connect pain or restriction to functional tasks.
Add your labelled upper-limb joints image here.
Learning outcomes
- Classify upper-limb joints and identify their articular surfaces.
- Describe the capsule, ligaments, movements and stabilisers of the shoulder girdle and glenohumeral joint.
- Explain the elbow complex, proximal/distal radioulnar joints, wrist and hand joints.
- Relate joint design to mobility, stability, arthrokinematics and common injuries.
- Apply joint anatomy to assessment, exercise selection, mobilisation precautions and activities of daily living.
1. Joint principles
A joint is a junction between bones or cartilages. Fibrous and cartilaginous joints provide little movement and stability; synovial joints have a cavity, articular cartilage, capsule and synovial fluid. The upper limb contains both true synovial joints and the functional scapulothoracic articulation.
| Feature of a synovial joint | Function | Physiotherapy relevance |
|---|---|---|
| Hyaline articular cartilage | Low-friction surface and load distribution. | Cartilage damage may cause pain, stiffness and altered loading. |
| Fibrous capsule | Encloses the joint and limits excessive translation. | Capsular shortening produces characteristic movement restriction. |
| Synovial membrane/fluid | Lubrication, nourishment and waste removal. | Inflammation can cause effusion, warmth and pain. |
| Ligaments | Guide and restrain movement; provide proprioception. | Sprains compromise stability; healing requires graded loading. |
| Labrum/disc/meniscus | Deepen a socket, improve congruence or distribute load. | Labral or disc injury may cause catching, instability or reduced function. |
| Muscles/tendons | Dynamic stability and movement. | Strength, timing and motor control often determine practical stability. |
2. Shoulder girdle joints
2.1 Sternoclavicular joint
The sternoclavicular (SC) joint is a saddle-type synovial joint between the medial clavicle, clavicular notch of the manubrium and first costal cartilage. An articular disc divides the joint and improves congruence. It is the only bony connection between the upper limb and axial skeleton.
- Ligaments: anterior/posterior sternoclavicular, interclavicular and costoclavicular ligaments.
- Movements: elevation/depression, protraction/retraction and axial rotation of the clavicle.
- Clinical point: the strong costoclavicular ligament and disc protect the joint, but trauma can displace the clavicle; posterior displacement may threaten mediastinal structures.
2.2 Acromioclavicular joint
The acromioclavicular (AC) joint is a plane synovial joint between the lateral clavicle and acromion. It permits small gliding and rotation that are essential for full overhead elevation.
- Acromioclavicular capsule/ligament: local restraint.
- Coracoclavicular ligament: conoid and trapezoid parts suspend the scapula from the clavicle and resist separation.
- Injury: an AC sprain or “shoulder separation” may disrupt the coracoclavicular complex; assess contour, pain and function without forcing loading.
2.3 Scapulothoracic articulation
This is a functional gliding interface between the anterior scapula, subscapular tissues and thoracic wall, not a conventional synovial joint. The serratus anterior, trapezius, rhomboids, levator scapulae and pectoralis minor control its movement.
| Scapular movement | Functional example | Main contributors |
|---|---|---|
| Elevation/depression | Shoulder shrug or lowering a load. | Upper trapezius/levator; lower trapezius and depression control. |
| Protraction/retraction | Reaching forward or pulling an object. | Serratus anterior/pectoralis minor; trapezius/rhomboids. |
| Upward/downward rotation | Overhead reach or returning the arm. | Upper/lower trapezius with serratus anterior; rhomboids/levator/pectoralis minor assist downward rotation. |
| Anterior/posterior tilt | Scapula adapts to humeral elevation and thoracic posture. | Balance of serratus, trapezius, pectoralis minor and trunk position. |
3. Glenohumeral (shoulder) joint
The glenohumeral joint is a ball-and-socket synovial joint between the humeral head and the shallow glenoid cavity. It offers flexion, extension, abduction, adduction, internal/external rotation and circumduction, but its mobility makes it vulnerable to instability.
3.1 Stabilising structures
- Glenoid labrum: fibrocartilaginous rim that deepens the socket and provides attachment for the capsule and long head of biceps.
- Joint capsule: loose inferiorly to allow elevation; attaches around the glenoid and anatomical neck.
- Glenohumeral ligaments: superior, middle and inferior bands reinforce the anterior capsule; the inferior complex is important in abduction/external rotation.
- Coracohumeral ligament: supports the superior capsule and rotator-interval region.
- Coracoacromial arch: protects the superior joint but may contribute to subacromial compression in some conditions.
- Rotator cuff: supraspinatus, infraspinatus, teres minor and subscapularis compress the humeral head into the glenoid and guide rotation.
- Long head of biceps: passes through the joint region and intertubercular groove; assists dynamic stability and shoulder flexion.
3.2 Movement and arthrokinematics
| Movement | Prime contributors | Key joint/clinical point |
|---|---|---|
| Flexion | Anterior deltoid, clavicular pectoralis major, coracobrachialis, biceps. | Requires scapular upward rotation for full range. |
| Extension | Posterior deltoid, latissimus dorsi, teres major, long head triceps. | Posterior capsule and anterior structures may limit end range. |
| Abduction | Supraspinatus initiates; deltoid continues. | Scapulohumeral rhythm combines glenohumeral and scapular motion. |
| Adduction | Pectoralis major, latissimus dorsi, teres major, long head triceps. | Closed-chain adduction helps push and weight-bearing tasks. |
| External rotation | Infraspinatus, teres minor, posterior deltoid. | Important for reaching behind the head; vulnerable in anterior instability. |
| Internal rotation | Subscapularis, pectoralis major, latissimus dorsi, teres major, anterior deltoid. | Needed for dressing, grooming and reaching the back. |
In a convex-on-concave open-chain movement, the humeral head rolls and glides in opposite directions; in closed-chain tasks, the glenoid moves on the humeral head. Apply this principle cautiously because real movement includes translation, rotation, soft-tissue deformation and scapular motion.
4. Elbow complex
The elbow complex comprises the humeroulnar, humeroradial and proximal radioulnar joints within a common capsule. Together they position the hand by flexing/ extending the elbow and rotating the forearm.
| Joint | Articular surfaces | Main role |
|---|---|---|
| Humeroulnar | Trochlea and trochlear notch of ulna. | Stable hinge for flexion and extension. |
| Humeroradial | Capitulum and radial head. | Shares load and guides elbow motion; accommodates forearm rotation. |
| Proximal radioulnar | Radial head and radial notch/annular ligament. | Pivot for pronation and supination. |
4.1 Stability and movement
- Medial and lateral collateral ligaments resist valgus and varus stress.
- The annular ligament holds the radial head against the ulna while allowing rotation.
- Olecranon and coronoid processes provide bony stability; the capsule is loose anteriorly/posteriorly.
- Flexion is produced mainly by brachialis, biceps and brachioradialis; extension by triceps and anconeus.
- Pronation uses pronator teres and pronator quadratus; supination uses biceps and supinator.
The carrying angle is the lateral deviation of the forearm relative to the arm in extension and supination. It varies with sex, age, position and measurement method; document the method instead of assuming a single normal value.
5. Distal radioulnar joint and interosseous membrane
The distal radioulnar joint is a pivot-type synovial joint between the ulnar head and the ulnar notch of the radius. The triangular fibrocartilage complex (TFCC) stabilises the ulnar side of the wrist and separates the ulna from the carpus. The interosseous membrane links the shafts, transmits load and provides a broad attachment surface.
- During pronation/supination, the radius rotates around the relatively stable ulna.
- Disruption of the interosseous membrane or TFCC can cause pain, weakness and instability with gripping or rotation.
- Assess elbow position, wrist load and forearm rotation separately during functional tasks.
6. Wrist and hand joints
6.1 Wrist
The radiocarpal joint is formed mainly by the distal radius and articular disc with the scaphoid, lunate and triquetrum. The ulna does not directly articulate with the carpal row. The midcarpal joint between proximal and distal carpal rows contributes substantially to flexion, extension and deviation.
| Movement | Main contribution | Functional example |
|---|---|---|
| Flexion | Radiocarpal and midcarpal motion. | Holding a bowl close to the body. |
| Extension | Radiocarpal and midcarpal motion. | Push-up support or pushing a door. |
| Radial deviation | Movement toward thumb side. | Positioning a spoon or turning a key. |
| Ulnar deviation | Movement toward little-finger side. | Using a hammer or steering wheel. |
6.2 Carpometacarpal and hand joints
- Thumb CMC: saddle joint between trapezium and first metacarpal; flexion, extension, abduction, adduction and opposition enable pinch.
- Digits 2–5 CMC: relatively stable plane joints that form the base of the hand arch.
- MCP joints: condyloid joints permitting flexion/extension and abduction/adduction; collateral ligaments tighten in flexion.
- Interphalangeal joints: hinge joints; PIP and DIP flexion/extension in digits 2–5, one IP joint in the thumb.
- Palmar plates and collateral ligaments: reinforce the volar side and guide joint motion.
7. Joint function in physiotherapy
| Assessment question | What joint anatomy contributes |
|---|---|
| Is the restriction capsular? | A joint capsule, synovium, ligaments and muscle may all limit motion; compare the pattern and end feel. |
| Is stability adequate? | Consider static restraints, labrum/TFCC, muscle timing, proprioception and load. |
| Is the movement isolated? | Check adjacent joints and compensations; shoulder elevation includes clavicle, scapula, humerus and thorax. |
| Can the patient load the joint? | Consider tissue healing, pain, swelling, bone quality, surgical restrictions and functional need. |
8. Common clinical patterns
- Anterior shoulder dislocation: often occurs in abduction/external rotation; protect the joint, assess axillary sensation and follow reduction/immobilisation orders.
- Adhesive capsulitis: pain and capsular restriction, commonly affecting external rotation, abduction and flexion; rule out other causes.
- AC sprain: pain at the AC region, especially cross-body movement; grade and management require clinical assessment.
- Lateral epicondylalgia: pain near common extensor origin, often load-related; assess the whole kinetic chain.
- Elbow stiffness: can quickly affect hand-to-mouth, dressing and reaching; protect healing structures while restoring motion.
- Carpal tunnel/hand stiffness: joint position, tendon glide, nerve sensitivity and swelling may interact.
9. Practical learning activities
- Identify the SC, AC, glenohumeral, humeroulnar, radioulnar, radiocarpal, CMC, MCP and IP joints on a model.
- Observe scapulohumeral rhythm during slow arm elevation and note clavicular and scapular contributions.
- Compare open-chain shoulder rotation with closed-chain hand-on-wall movement.
- Demonstrate how elbow flexion and forearm rotation position the hand for feeding and grooming.
- Practise documenting a joint range with position, side, movement, pain, end feel and functional effect.
10. Examination points and revision questions
High-yield points
- The SC joint is the only true bony link between upper limb and axial skeleton.
- Glenohumeral mobility depends on the labrum, capsule, ligaments, rotator cuff and scapular control.
- The elbow complex includes humeroulnar, humeroradial and proximal radioulnar joints.
- The radius rotates around the ulna during pronation and supination.
- Thumb opposition depends on the saddle CMC joint and coordinated intrinsic/extrinsic muscles.
- Describe the joints of the shoulder girdle and explain scapulohumeral rhythm.
- Discuss the stabilising structures of the glenohumeral joint.
- Compare the three joints of the elbow complex.
- Explain the roles of the TFCC and interosseous membrane.
- Describe the wrist, thumb CMC, MCP and interphalangeal joints.
- Relate joint mobility and stability to reaching, pushing, gripping and dressing.
References for further study
- OpenStax: Selected synovial joints
- OpenStax: Joints and skeletal movement
- OpenStax: Upper-limb joint review
- TeachMeAnatomy: Upper-limb joints
Educational note: Joint mobilisation, manipulation and post-injury loading require supervised training and adherence to local protocols.