Mednotes

L29 MSK Radiology 3 Radiology of the Upper Limb

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tagsmsk, lecture
aliasesL29 MSK Radiology 3 Radiology of the Upper Limb

14 min read

Overview

This lecture reviews the normal anatomy of the upper limb (shoulder, elbow and wrist) and how it appears on plain radiographs, covers the imaging modalities and radiographic technique used to assess each region, and works through a series of clinical cases illustrating common upper limb injury patterns and other pathologies.

Shoulder: bony and soft tissue anatomy

  • Proximal humerus (anterior view labels): head of humerus, anatomical neck, greater tubercle, lesser tubercle, intertubercular sulcus (bicipital groove), surgical neck, crest of greater tubercle, crest of lesser tubercle, shaft of humerus, deltoid tuberosity.
  • Scapula (lateral view labels): acromion, supraglenoid tubercle, coracoid process, glenoid fossa, infraglenoid tubercle.
  • Clavicle: conoid tubercle, acromial end, body of clavicle, sternal end.
  • Rotator cuff: the four rotator cuff muscles are supraspinatus, infraspinatus, subscapularis and teres minor, shown surrounding the humeral head.
  • Other labels on the rotator cuff diagrams: rotator interval, supraspinatus and external rotator muscles, long tendon of biceps brachii (biceps brachii long head tendon), anatomical neck, greater tuberosity/greater tubercle, surgical neck, lesser tuberosity, acromion, coracoid process, shaft of humerus. [slide labels these structures but does not state how they are positioned relative to one another]
  • Coronal T2 MRI of the right glenohumeral joint demonstrates the supraspinatus tendon, the glenoid labrum and the deltoid muscle.

Shoulder: arterial anatomy on angiography

A digital subtraction angiogram of the shoulder region is shown alongside a matching anatomical illustration of the same arterial territory.

  • Vessels labelled on the angiogram: dorsal scapular artery, thoracoacromial artery (pectoral branches), subclavian artery, axillary artery, anterior circumflex humeral artery, circumflex scapular artery, thoracodorsal artery, subscapular artery.
  • Further vessels labelled on the companion illustration: clavicular branch, acromial anastomosis, acromial branch, deltoid branch, superior thoracic artery, thoracoacromial trunk, pectoral branch, posterior circumflex humeral artery, lateral thoracic artery, brachial artery, profunda brachii artery.
  • Non-vascular landmarks labelled for orientation: humerus, coracoid process of scapula, pectoralis minor, teres major.
  • [slide gives these as labels only: it does not state which vessel arises from which, or the order in which the branches arise]

Brachial plexus

  • Organisation: 5 roots (C5-T1), 3 trunks, 6 divisions, 3 cords, 5 branches. The trunks are superior, middle and inferior; each trunk gives an anterior and a posterior division; the cords are lateral, posterior and medial; the terminal branches labelled are the musculocutaneous, median, axillary, ulnar and radial nerves. The axillary artery is labelled running with the plexus. The plexus is divided into a supraclavicular part and an infraclavicular part.
  • Additional named branches shown on the diagram: phrenic nerve (from the cervical plexus), dorsal scapular nerve, muscular branches, suprascapular nerve, subclavian nerve, lateral pectoral nerve, subscapular nerve, thoracodorsal nerve, medial pectoral nerve, long thoracic nerve, intercostal nerve.
  • Clinical assessment at the bedside (motor function): median nerve - thumb-to-index finger “OK” pinch sign; ulnar nerve - finger crossing/abduction test; radial nerve - wrist and thumb extension.
  • Brachial plexus MRI: a coronal MRI of the neck and upper chest, with the vertebral levels labelled from C2 through T3, and the plexus divisions (purple) and the lateral cord (orange/tan) highlighted and identified in a colour-coded legend.

Shoulder: radiographic views and other imaging

  • Standard radiographic views demonstrated, each with a photograph of patient positioning alongside the resulting film:
    • AP external rotation
    • AP oblique
    • Trans-scapular Y view - patient’s back to the detector, giving a “Y”-shaped scapular projection
    • Axillary view - arm abducted, showing the glenohumeral joint from above
  • Ultrasound: used to image the supraspinatus tendon (image labelled “RT Supra-spinatus LONG”, with cursor measurement markers across the tendon) and to guide injection into the shoulder under direct vision.
  • Arthrogram: a fluoroscopic shoulder arthrogram with the needle in place within the joint, shown alongside a coronal T2-weighted MRI in which joint fluid/contrast outlines the joint space and the labrum.

On the "radiographic anatomy" slides, three shoulder radiographs (two AP-type views and an axillary view) carry yellow numbered labels 1 to about 16, with a dotted line tracing the humeral head/neck contour on the first image, but the numbers are not matched to a legend, so the structure named by each number cannot be confirmed.

Shoulder: cases

  • Case 1 - 18-year-old male, impact to the left shoulder during rugby. An AP shoulder/chest film showing ribs, clavicle, scapula and proximal humerus is posed with the question “which bone/s is/are abnormal?” [no answer is given on the slide]
  • Case 2 - 35-year-old male, shoulder injury. AP shoulder/chest film, then an “AP - Anterior View”, a “Y” view and a close-up of the glenohumeral joint, followed by the teaching point: posterior shoulder dislocation, in which the humeral head takes on a rounded “lightbulb” appearance on the AP erect film.
  • Case 3 - 50-year-old male, shoulder pain. An AP shoulder film with a red arrow pointing to a dense/opaque area adjacent to the greater tuberosity/subacromial region.
  • Case 4 - 50-year-old woman, chronic shoulder pain. An AP shoulder film posed with the question “what process is occurring?” [no answer is given on the slide]

Two case slides carry unresolved detail: on the Case 2 view slide, small attribution text along the bottom edge of the AP and "Y" view images is illegible; on the Case 3 slide, the arrow highlights a finding but no text on the slide names it.

Elbow: anatomy

  • Distal humerus: lateral supracondylar ridge, medial supracondylar ridge, radial fossa, coronoid fossa, olecranon fossa, lateral epicondyle, medial epicondyle, capitulum, trochlea of humerus.
  • Proximal radius: head, neck, radial tuberosity.
  • Proximal ulna: coronoid process, radial notch, tuberosity of ulna, trochlear notch, olecranon, groove for the ulnar nerve, sublime tubercle.
  • These are shown on right elbow illustrations in extension (anterior, posterior, lateral and medial views) and at 90 degrees of flexion (lateral and medial views).

Elbow: radiographic technique and assessment

  • Two projections are shown, each paired with a diagram of the arm positioned against the detector for that projection: AP and lateral.
  • Radiocapitellar line: drawn on the AP elbow film through the radial neck and the capitellum.
  • Anterior humeral line: drawn on the lateral elbow film along the anterior humeral cortex through the capitellum.
  • Paediatric elbow ossification centres are labelled by single letters on AP and lateral films, and follow the CRITOE mnemonic in order of appearance:
    • C = Capitellum, 1 year
    • R = Radial head, 3 years
    • I = Internal (medial) epicondyle, 5 years
    • T = Trochlea, 7 years
    • O = Olecranon, 9 years
    • E = External (lateral) epicondyle, 11-12 years
  • Elbow joint effusion: the lateral film is the view used, with the joint capsule and fat pad anatomy shown by colour overlay; an effusion is seen as an elevated/displaced anterior fat pad.

Elbow joint effusion in a child with no visible fracture may indicate an occult supracondylar fracture. The anterior humeral line drawn on the lateral film can reveal such a fracture when no fracture line is directly visible.

  • Case 5 - 40-year-old male, fell on an outstretched hand, “which bone is broken?”. The AP elbow film has markers over both epicondyle/fat pad regions; the lateral film shows a fracture line at the radial head/neck.

Wrist and hand: anatomy

  • Hand bones by category, with the parts named for each: distal phalanges (head, tuberosity, body, base), middle phalanges (head, body, base), proximal phalanges (head, body, base), metacarpal bones (head, body, base), and the carpal bones (trapezium, trapezoid, capitate, scaphoid, lunate, hamate, triquetrum named on the illustration).
  • Eight carpal bones in two rows, given by the mnemonic “Straight Line To Pinky, Here Comes The Thumb”:
    • Proximal row: scaphoid, lunate, triquetrum, pisiform
    • Distal row: trapezium, trapezoid, capitate, hamate
  • On the labelled AP wrist film, the hook of hamate is labelled in addition to the eight carpal bones.
  • The carpal bones are also identified on the lateral wrist film, with a colour overlay marking radius, scaphoid, lunate, triquetrum, pisiform, capitate, trapezoid and trapezium, and distinguishing the proximal row (red) from the distal row (teal).

On the labelled hand AP xray the numbered labels 1 to 22 are not individually matched to names in a legend, so only the bone categories grouped in the companion illustration can be confirmed, not each specific numbered structure.

Wrist: imaging and cases

  • Radiographic projections shown: PA, oblique and lateral.
  • Cross-sectional imaging of the carpal bones: axial CT and axial proton-density fat-saturated (PD FS) MRI at a similar level, both showing the carpal bone contours.
  • Case 6 (AP wrist film) and Case 7 (PA wrist film) are presented without further case detail or a stated finding.
  • Case 8 - 20-year-old female, FOOSH (fall onto an outstretched hand). PA and lateral wrist films are shown, followed by the teaching point: Colles fracture, which is extra-articular with dorsal angulation of the distal fragment.
  • Distal radius fractures are the most common orthopaedic injury. Management: closed reduction and immobilisation in a cast, or ORIF (open reduction internal fixation) if unstable, shown as a volar locking plate and screws on post-operative PA and lateral films.

A PA wrist film shows a coloured overlay over the scapholunate region between the scaphoid and lunate, but the overlay shapes are not individually labelled, so the exact structures depicted (most likely components of the scapholunate ligament complex) cannot be confirmed from the slide.

Closing summary of material covered

The lecture’s summary states it has covered a review of normal upper limb anatomy and its xray appearance, together with these common injury patterns and their xray appearance: glenohumeral dislocation, clavicle fracture, supracondylar and radial head fracture, distal radius fracture, and scaphoid fracture with avascular necrosis (AVN) and triquetral fracture. Other pathologies named: inflammatory arthritis and calcific tendinopathy.

Self-test

  1. List the parts of the proximal humerus labelled in this lecture.
  2. List the features labelled on the scapula and on the clavicle in this lecture.
  3. Name the four rotator cuff muscles and state what the diagram shows of their relationship to the humeral head.
  4. List the structures, other than the four rotator cuff muscles, labelled on this lecture’s rotator cuff diagrams.
  5. Describe the organisation of the brachial plexus from roots to terminal branches, giving the number of structures at each level and naming them.
  6. List the additional named branches, beyond the five terminal branches, shown on the brachial plexus diagram.
  7. Distinguish the bedside motor tests used for the median, ulnar and radial nerves.
  8. List the vessels labelled on this lecture’s shoulder digital subtraction angiogram and its companion illustration.
  9. List the four shoulder radiographic views demonstrated, with the positioning the lecture states for each.
  10. Describe the appearance of the humeral head on the AP erect film in posterior shoulder dislocation.
  11. List the imaging modalities other than plain radiography used in the shoulder and brachial plexus part of this lecture, and give one use of each.
  12. Describe what the coronal brachial plexus MRI in this lecture labels.
  13. List the features labelled on the distal humerus.
  14. List the features labelled on the proximal radius and the proximal ulna.
  15. List the CRITOE ossification centres in order of appearance, with their approximate ages.
  16. Distinguish the radiocapitellar line from the anterior humeral line.
  17. Explain what an elbow joint effusion in a child with no visible fracture suggests, and how the film can be assessed further.
  18. Describe the finding on the elbow radiographs of the 40-year-old man who fell on an outstretched hand.
  19. List the parts named for the phalanges and for the metacarpal bones in this lecture’s hand illustration.
  20. List the eight carpal bones by row using this lecture’s mnemonic, and name the extra bony landmark labelled on the AP wrist film.
  21. Describe how the carpal bones are identified on the lateral wrist film in this lecture.
  22. List the three wrist projections shown and the two cross-sectional modalities used for the carpal bones.
  23. Define a Colles fracture as described in this lecture and give its two management options.
  24. Beyond the cases shown with images, list the injury patterns and other pathologies named in the closing summary.
  25. A patient falls onto an outstretched hand: name the two fractures demonstrated by this lecture’s FOOSH cases, and say on which projection each was seen.

Answers

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