Human Anatomy
Upper Limb Joints and Surface Marking
Upper limb joints for MBBS: shoulder, elbow, radio-ulnar and wrist joints with movements, radiographs and surface marking, mapped to NMC codes AN13.1 to AN13.8.
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Upper Limb Joints and Surface Marking
Upper limb joints for MBBS: shoulder, elbow, radio-ulnar and wrist joints with movements, radiographs and surface marking, mapped to NMC codes AN13.1 to AN13.8.
This chapter draws together the joints of the upper limb, their movements and stability, and the surface marking of the main vessels and bony landmarks. It covers the shoulder, elbow, radio-ulnar and wrist joints and the clinical anatomy of dislocation and impingement.
High-yield: Upper Limb Joints and Surface Marking
- The shoulder is a ball-and-socket synovial joint that trades stability for a very wide range of movement.
- The glenoid cavity is deepened by the fibrocartilaginous glenoid labrum.
- The rotator cuff muscles are supraspinatus, infraspinatus, teres minor and subscapularis, and they stabilise the shoulder.
- The shoulder is weakest inferiorly, where dislocation most often occurs, endangering the axillary nerve.
- The elbow is a hinge joint between the trochlea and capitulum of the humerus and the ulna and radius.
- The carrying angle is the lateral angle between the arm and forearm when the elbow is extended and supinated.
- The superior radio-ulnar joint is a pivot joint that allows pronation and supination with the inferior radio-ulnar joint.
- The wrist is a condyloid joint between the radius and the scaphoid, lunate and triquetral bones.
- The saddle joint between the trapezium and first metacarpal allows opposition of the thumb.
- On the front of the wrist the three-point relation is the palpable tendons of palmaris longus and flexor carpi radialis, with the radial pulse lateral.
- The surface marking of the axillary artery runs from the mid-point of the clavicle to a point behind the coracoid process.
- The head of the radius is felt in a dimple on the back of the extended elbow and rotates during supination.
- The subacromial bursa lies between the acromion and supraspinatus and is a common site of impingement.
- The three bony points at the elbow, the two epicondyles and the olecranon, form an equilateral triangle in flexion and a straight line in extension.
Major upper limb joints
- **Shoulder:** Ball-and-socket; wide range but least stable inferiorly; rotator cuff gives active stability.
- **Elbow:** Hinge joint; flexion and extension; carrying angle when extended and supinated.
- **Radio-ulnar joints:** Superior and inferior pivot joints producing pronation and supination.
- **Wrist:** Condyloid joint between radius and proximal carpals; flexion, extension, abduction, adduction.
NMC competencies in this chapter
- **AN13.1:** Shoulder joint: type, ligaments and movements
- **AN13.2:** Elbow joint: type, ligaments and movements
- **AN13.3:** Radio-ulnar joints and pronation-supination
- **AN13.4:** Wrist and joints of the hand
- **AN13.5:** General features and movements of the upper limb
- **AN13.6:** Surface marking of vessels and nerves of the upper limb
- **AN13.7:** Radiographs of the upper limb
- **AN13.8:** Applied anatomy of upper limb joints
Frequently Asked Questions
Why does the shoulder dislocate most often inferiorly?
The shoulder joint is least supported below, where there is no rotator cuff muscle, so the head of the humerus tends to dislocate downward. This can injure the nearby axillary nerve.
What is the carrying angle?
The carrying angle is the outward angle between the arm and the forearm when the elbow is extended and the forearm supinated. It lets the extended limbs clear the hips when walking.
Which joints produce pronation and supination?
The superior and inferior radio-ulnar joints, both pivot joints, work together to rotate the radius over the ulna, producing pronation and supination of the forearm.
What are the three bony points at the elbow?
The medial and lateral epicondyles of the humerus and the olecranon of the ulna form a triangle when the elbow is flexed and a straight line when extended. A disturbed relation suggests dislocation.
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