Week 10 - finished Flashcards
What articulations comprise the elbow complex?
- humeroulnar joint
- Distal and Prox radioulnar joint
- humeroradial joint
What is the carrying angle of the elbow?
- the valgus angulation of the forearm in relation to the humerus
- approx. 5-10 degrees in men
- approx. 10-15 degrees in women
At what age does each of the major bony structures of the elbow ossify? How does this influence “pulled elbow”?
elbow ossification centres = “come rub my tree of love”
- Capitulum = 1 yoa
- Radial head = 5 yoa
- Medial epicondyle = 5 yoa
- Trochlea = 11 yoa
- Olecranon = 12 yoa
- Lateral epicondyle = 13 yoa
pulled elbow = sublaxation of the radial head, most common in traumatic elbow injury in children, usually around 2-5 yrs as radial head ossifies after this age, as well as the thickening of the annular ligament
What ligaments support the radioulnar joint?
Ladies, RU A Quiet Orgasmer Inside
- annular ligament = attaches to the ant and post borders of the radial notch, creating a ring in which the rim of the radial head is enclosed
- quadrate ligament = extends from the inf edge of the radial notch (ulna) to the neck of the radius. Reinforces the inf jt capsule and maintains approximation of radial head to radial notch. Limits the spin of the radial head in pronation and supination
- Oblique cord = Extends from inf to the radial notch (ulna) to inf to the bicipital tub of the radius. Prevents separation of the ulna and radius and limits supination. Fibre orientation is perpendicular to that of the interosseous membrane
- interosseous membrane = The interosseous mem connects the med border of the radius & lat border of the ulna. It is a strong, broad collagenous sheet, which begins 2-3cm distal to the radial tub. The distal end is continuos, via a tract, with the distal radioulnar joint capsule and articular disc. Its fibres run distally and medially from radius to ulna & functions to:
- Provides stability to both radioulnar joints
- Transmits forces from the hand and distal radius to the ulna
- Provides proximal attachment for the deep muscles of the forearm - Radioulnar ligaments = The dorsal & palmar radioulnar ligs are capsular ligs found @ the margins of the disc in the distal radioulnar jt. In full supination the palmar ligament is taut and dorsal is lax. In full pronation the dorsal ligament is taut and the palmar is lax
List the mms which flex the elbow
3b’s bend the elbow
- brachialis
- biceps brachii
- brachioradialis
secondary flexors
- PT
- FCR
- FCU
- FDS
- PL
List the mms which supinate the elbow
- Supinator
- Biceps brachii
List the borders and the contents of the cubital fossa
BORDERS
- Superior = imaginary line b/w med an lat epicondyles
- Medial = lateral border of PRONATOR TERES
- Lateral = medial border of BRACHIORADIALIS
- Floor = brachialis and supinator muscles
- Roof = Brachial fascia, bicipital aponeurosis, superficial fascia and skin
CONTENTS (LAT TO MED)
- radial nerve
- biceps tendon
- brachial artery
- median nerve
Which bones contribute to the radiocarpal joint? What is the midcarpal joint?
radiocarpal = radius, scaphoid, lunate, triquetrum
midcarpal = articulation b/w the prox and distal rows of carpal bones
Which carpal most commonly becomes unstable? How can this relate to carpal tunnel syndrome? What orthopaedic tests are used to asses carpal stability?
- The scaphoid is often involved in carpal instability
- lunate 2nd most common
- Due the carpal tunnel attachments the carpal tunnel may be affected by the movement of the scaphoid.
- If the scaphoid has become unstable due to traumatic events eg. FOOSH we will see swelling/ inflammation within the carpal tunnel causing carpal tunnel syndrome SSX.
- Scapholunate rupture = Waton’s test (scaphoid shift test)
- To check lunate stability = ballotement test (shearing whist holding lunate)
What carpal is most commonly fractured? What variation in blood supply is significant in this fracture?
- Scaphoid in a FOOSH injury (with partially ulna deviation)
- About 10% of people have blood supply from only the radial artery which enters from the distal aspect of
the bone. A fracture may result in avascular necrosis of the PROXIMAL-===== portion.
List the mms that extend the wrist
- ECRL and ECRB
- ECU
secondary extensors
- ED
- EI
- EDM
- EPL
List the borders and contents of the anatomical snuff box
floor = scaphoid and trapezium
lateral border = AbPL and EPB
medial border = EPL
contents = radial artery, radial nerve (sup. branch), cephalic vein
What is the path of the ulnar artery and nerve into the hand?
ULNAR ARTERY
- branch of brachial (bifurcation inferior to elbow around neck of radius)
- lies b/w FDP and FDS
- passes medially to pisiform and into hand via tunnel of Guyon
ULNAR NERVE
- over flexor retinaculum
- through Guyon’s canal and and into medial hand
List the muscles supplied by the musculocutaneous nerve
- Biceps brachii
- Brachialis
- Coracobrachialis
Why is palmar sensation and 5th digit sensation generally spared in cases of carpal tunnel syndrome?
Palmar innervation is via the superficial palmar branch of
the median N which travels superiorly to the flexor retinaculum (AKA transverse carpal ligament)
5th digit (and 1/2 of the 4th digit) palmar surface is supplied by the ulnar nerve which travels through the tunnel of guyon (where the flexor retinaculum is the floor)