15.2, 15.4, 15.6 Flashcards by Hamish T

4 joints of shoulder complex:

Sternoclavicular joint.
Acromioclavicular joint.
Glenohumeral joint.
Scapulothoracic joint.

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The clavicle curves forwards in the ___ 2/3s and then curves backwards.

Medial

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Fractures of clavicle occur a the change of curvature between ___ 2/3s and ___ 1/3

Medial 2/3s and lateral 1/3s where clavicle changes direction

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There is a ___ ___ in the sternoclavicular joint

Intraarticular disc

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There is a band of ligamentous fibres from ___ rib to undersurface of clavicle, creating a ___

First rib
Creates tubercle
Forms costoclavicular ligament - the main stabiliser of the sternoclavicular joint (note that this joint is also reinforced by sternoclavicular ligament, but this is not then main stabiliser).

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The ___ joint is rarely disrupted due to its stability, which is good because the ___ vessels are directly posterior to it!

Sternoclavicular joint

Subclavian artery and vein

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There is a ___ joint at the lateral end of the clavicle

Acromioclavicular joint (synovial), NOT a strong joint!

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The acromioclavicular joint is not a strong joint, so subluxation of this joint is more common c.f. ___ ____

Sternoclavicular joint

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The main stabiliser of the acromioclavicular joint is the ___ ___

Coracoclavicular ligament
This attaches to the coracoid process, and has two parts.
Note there is an acromioclavicular ligament but this is NOT the main stabiliser at the joint.

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Grades of acromioclavicular subluxation:

Grade 1 - acromioclavicular ligaments are stretched but not torn
Grade 2 - AC ligaments are torn
Grade 3 - AC AND coracoclavicular ligaments (the main stabilisers at this joint) are both torn!

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Layers of glenohumeral joint:

1 - bones
2 - labrum
3 - capsule
4 - tendons ("rotator cuff")
5 - coraco-acromial (accessory) ligament/arch and subacromial bursa

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The shoulder joint has the ___ range of movement of all joints in the body

Greatest

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Deficiencies in capsule of shoulder joint?

One for tendon of long head of biceps to come out of joint.

One for bursa (subscapular) - note this communicates with joint!

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Muscles of rotator cuff?

Supraspinatus
Infrapsinatus
Subscapularis
Teres minor

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When rotator cuff muscles contract, they ___ the capsule and increase ___

Tighten
Increase stability
So main role as stabilisers, but also involved in prime movement

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To access the shoulder joint, ___ muscle passes under the ___ ligament in a small space

Supraspinatus muscle/tendon

Coracoacromial ligament

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If rotator cuff muscles are weak, and deltoid contracts - pulls up the ___ which can impinge on the tendon of ___

Humerus

Supraspinatus

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Impingement of supraspinatus tendon can lead to an ___ reaction

Avascular

Formation of calcium deposits in tendon!

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If instability at shoulder joint and deltoid contracts to pull up humerus, the ___ can be impinged against by bone or ligament

Subacromial bursa!

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The shoulder joint is unstable and susceptible to either ___ or ___

Subluxation

Dislocation

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When the arm is in an ___ position, it is esp. vulnerable

Abduction

Small amount of head of humerus in contact with glenoid fossa

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The most common dislocation at the shoulder joint is ___ and ___

Anterior and inferior

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In shoulder dislocation, the ___ nerve is esp. susceptible to injury

Axillary nerve
Because it passes under head of humerus - so if humerus dislocates anterior and inferiorly, it is esp. susceptible to injury

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Axillary nerve passes through a ___ space bounded by:

Quadrangular/quadrilateral

Bounded by shaft of humerus, long head of triceps, teres major and subscapularis

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If you suspect dislocation of the shoulder, do not let patient ___ the arm!

Abduct! Negative effects on axillary nerve. Test cutaneous supply by military badge area!

There are ___ ligaments from medial and lateral epicondyles

Collateral ligaments

The radial tuberosity on the radius is the attachment for

Biceps! | Located anteromedial

If ligaments/muscles attach, there are ___ epiphyses

Traction

In children, the ligament is often ___ than the bony attachment

Stronger - risk of avulsion

Epiphyses of bones at elbow joint form at different ___

Ages E.g. capitulum at 2 years E.g. epicondylar epiphysis at 8 years

The ___ joint and ___ ___ joint SHARE THE SAME CAPSULE

Elbow joint and proximal radioulnar joint

There are ___, ___ fat pads in the anterior and posterior fossae of the elbow joint

Intracapsular, extrasynovial

The medial collateral ligament attaches to __

Ulna

The lateral collateral ligament does NOT attach to ___, but attaches to the ___ ligament

Bone | Attaches to annular ligament to form 2/3s of circle around neck of radius.

When the forearm is extended, the medial ___, ___ and lateral ___ are all in the same line from medial-lateral and lateral-medial

Epicondyle Olecranon Epicondyle

There is a ___ angulation when elbow is extended - forearm at angle of approx ___ degrees

Valgus angulation | 15 degrees

Valgus angulation disappears in ____

Flexion

If there is an increase in valgus angulation, there can be additional tension on structures on the ___ side

Medial e.g. medial collateral ligament, but esp. on structures that pass BEHIND medial epicondyle like the ULNAR NERVE!

Radioulnar joints control ___ and ___ of the forearm

Pronation and supination!

There is a ___ disc in the joint cavity of the inferior radioulnar joint

Fibrocartilaginous

Note - the ___ does NOT extend as far distally as the ___

Ulna less far than radius. | So ulna is NOT articular at wrist joint, it is separated by fibrocartilaginous disc

Fracture of one bone out of ___ and ___ is commonly associated with dislocation or fracture of the other - called the '___' principle due to interosseous membrane

Ulna or radius | Ring principle

There are 2 pronators and 2 supinator muscles contributing to movements at radioulnar joints:

2 pronators: pronator teres and pronator quadratus | 2 supinators: supinator and biceps brachii

Remember - there is a ___ in the olecranon fossa

Bursa! Susceptible to irritation if contact with hard/rough surfaces Called student's elbow!

At the elbow joint, the most common direction of dislocation is ___

Posterior

Volkmann's ischaemia

If posterior dislocation of elbow, can cause significant stretch on brachial artery causing the lumen to narrow -> ischaemia of forearm musculature!

Pisiform bone is a ___ bone i.e. it lies inside a ___

Sesamoid | Inside a tendon

The distal wrist crease is the ___ attachment of the ___ ___

Proximal attachment of flexor retinaculum

The proximal wrist crease marks the ___ joint

Wrist

___ and ___ (carpal bones) are articular at the wrist

Scaphoid and lunate

Falls on an outstretched hand can transmit force via the capitate into the ___ and ___

Scaphoid and lunate

Some carpal bones project forwards: ___, ___, ___, ___ (STOP)

Tubercle on scaphoid, tubercle on trapezium, hook of hamate and pisiform. Important for attachment of flexor retinaculum.

Carpal bones can only be used to determine age of child up to approx. ___ years old

Typically long bones ossify at both ends, but ___ only ossify at one end!

Metacarpals - but still a long bone

The ___ of the metacarpal is proximal and the ___ of the metacarpal is distal

Base Head (ossification centres at head!) BUT in other bones, usually ossification centres are proximal, not distal!

Bones articulating at wrist:

Scaphoid, lunate and distal radius.

Bones distal to articulating bones at wrist:

Trapezium, trapezoid, capitate, hamate (TTCH)

Flexion at wrist is ___ than extension, and ulnar deviation at wrist is ___ than radial deviation

Greater and greater

Why is flexion at wrist greater than extension?

Because posterior part of radius projects more distally than the anterior aspect.

Why is ulnar deviation at wrist greater than radial deviation?

In radial deviation, the radial styloid blocks movement!

The carpal bones are all connected by ___ ligaments

Interosseous

In the intercarpal joints: Extension is ___ than flexion Radial deviation is ___ than ulnar deviation BUT low ROM anyway c.f. wrist.

Greater And greater (I.e. opposite of wrist).

Anteriorly, there are palmar ligaments attaching to ___ and pass ___ across front of wrist, as far as metacarpals.

Radius, pass obliquely to metacarpals. | Palmar/volar radiocarpal ligament and palmar ulnocarpal ligament.

Posteriorly, there is a dorsal radiocarpal ligament that passes from ___, in ___ direction to carpal bones

Radius, obliquely to carpals

Palmar ligaments are ___ than dorsal ligaments | And radiocarpal ligaments are ___ than ulnocarpal ligaments

Stronger Stronger They act to prevent carpal bones from sliding medially.

Ligaments of carpal bones are stabilisers AND transmit ___ ___

Blood vessels to bones!

Specialised ligament - radio-scapho-lunate ligament:

Band from radius, over scaphoid and attaching to lunate. | Holds scaphoid and lunate in position, esp. lunate because tends to sublux into space on medial aspect.

___ ___ ___ attaches to pisiform

Flexor carpi ulnaris

6% of all fractures in the body are in the ___ radius and ___ bones

Distal radius and carpal bones

In fracture of scaphoid, can sometimes lead to ___ ___ of proximal pole of scaphoid

Avascular necrosis | Due to distribution of vascular supply

The first metacarpal is separated from other 4 metacarpals - metacarpals 2-5 are connected by a deep ___ ___ ligament

Deep transverse metacarpal ligament | The 1st metacarpal is free - for flexion/ extension/ abduction/ adduction.

The carpometacarpal joint of the thumb is a ___ joint

Saddle - for opposition!

The lateral boundary of the anatomical snuff box is formed by 2 tendons:

Abductor pollicis longus (most lateral) | Extensor pollicis brevis

Fracture at base of 1st metacarpal:

Bennett's fracture

Fracture at neck of 5th metacarpal:

Boxer's fracture

Metacarpophalangeal joints are ___ joints

Condyloid

Why is there greater extent of abduction at MCP joints in extension at MCP c.f. in flexion at MCP

In flexion, the collateral ligaments tighten! If injuries of patient's hand - stabilise hand in FLEXION - so ligaments are tight If they are lax, then they will tighten! - Difficult to recover.