Upper Limb 4

Front 1

Osteology of the forearm

Back 1

Ulna is medial, radius is lateral.

Ulna is longer, head is distal.

Radius is shorter, head is proximal.

Both have styloid processes at distal end.

Front 2

Interosseous membrane

Back 2

Fibrous membrane that joins the ulna and radius.

Front 3

Osteology of the hand

Back 3

Hand has 8 carpal bones.
Scaphoid (lateral side) and lunate (medial side) are connection between radius and hand.

There are then 5 metacarpal bones linked to the carpals.

There are 14 phalanges, proximal middle and distal. Thumb is only finger with just two. Connected by two joints, the proximal and distal interpharyngeal joints (PIPJ and DIPJ).

Front 4

Cubital fossa (and borders)

Back 4

Transition area between arm and forearm.

Triangle depression anterior to elbow joint.

Boundaries of the fossa:
- superior: imaginary line between epicondyles
- medially: pronator teres
- laterally: brachioradialis

Front 5

Contents of cubital fossa

Back 5

(form lateral to medial)

- tendon of biceps brachii
- brachial artery (terminal branches are ulnar and radial arteries)
- median nerve


These are covered by bicipital aponeurosis. The median cubital vein courses over this.

Front 6

Dividing up the forearm

Back 6

Anterior and posterior compartments.

Anterior FLEX the digits and writs and PRONATE the hand.

Posterior EXTEND the wrist and digits, and supinate the hand.

Front 7

Interosseous membrane

Back 7

Fibrous membrane between radius and ulnus. Collagen courses inferomedially from radius to ulna.

Fiber orientation helps in dissipating force (avoiding FOOSH)

Front 8

Colles' fracture

Back 8

Distal radial fractures are most common type. Happens with FOOSH (like slipping on ice)

Radius fractures, creating a jog with heals readily because of rich blood supply. Known as dinner fork deformity.

Front 9

Antebrachial fascia (plus formations at wrist level)

Back 9

Deep fascia surrounding forearm musculature. Continuous with brachial fascia and deep hand fascia.

At wrist level, fascia thickens forming palmar carpal tunnel (anterior) and extensor retinaculum (posterior).

Underneath palmar carpal tunnel is flexor retinaculum.

Fascia helps bind tendons of forearm, prevents bowstringing.

Front 10

Brachioradialis

Back 10

Forearm muscle. Attaches to arm (brachium) and radius.

The ONLY flexor innervated by radial nerve (C5, 6, 7).

Front 11

Supinator

Back 11

Named according to action: supinates forearm and hand! (biceps helps)

Innervated by deep radial nerve (C5, C6)

Front 12

Superficial Flexor- Pronators

Back 12

1) Pronator teres
2) Flexor carpi radialis
3) Palmaris longus
4) Flexor carpi ulnaris
5) Flexor digitorum superficialis

PIMPS FUCK PROSTITUTES FOR FUN.

All innervated by median nerve except ulnaris (ulnar nerve).

Origin: common flexor tendon from medial epicondyle of humerus.

Front 13

Deep flexor pronators

Back 13

1) Flexor digitorum profundis
2) Flexor pollicis longus (thumb)
3) Pronator quadratus

All innervated by median nerve except profundus (half innervated by ulnar nerve)

Front 14

Pronation of the forearm

Back 14

Pronator quadratus initiates pronation at radioulnar joints. Pulls distal radius over ulna. Innervated by anterior interosseus nerve (C8 and T1, offshoot of median nerve)

Pronator teres assists quadratus to get more speed and power. Innervated by C6 and C7 of median nerve.

Front 15

Flexor digitorum superficialis

Back 15

Intermediate flexor. Two heads: humeroulnar and radial.

Gives rise to four tendons that pass below flexor retinaculum (roof of carpal tunnel). Split into four non-thumb phalanges.

Flexes middle phalanx at PIPJ.

Innervated by median nerve (C7, C8, T1).

Front 16

Flexor digitorum profundus

Back 16

Originates from ulna and interosseus membrane.

Divides into four tendons that go below flexor retinaculum (carpal tunnel) and into base of distal phalanx at DIPJ.

Innervated by C8 and T1 of ulnar nerve and median nerves.

Front 17

Functional extensor groups

Back 17

1) Extensors of wrist (3)
2) Extensors of digits (3)
3) Extensors/abductors of thumb (3)

All innervated by radial nerve (C6, C7, C8).

Many arise from common extensor tendon, or attachment on the lateral epicondyle of the humerus.

Front 18

Extensors of the wrist

Back 18

1) Extensor carpi radialis longus
2) Extensor carpi radialis brevis
3) Extensor carpi ulnaris

All arise from common extensor tendon.

All insert on metacarpal bases.

Extend and stabilize wrist.

Front 19

Extensors of the digits

Back 19

1) Extensor digitorum (x)
2) Extensor indicis (located deeper)
3) Extensor minimi (little finger)

Long tendons of these muscles insert into extensor expansion of digits, a triangular expansion of extensors.

Front 20

Extensor expansion AKA hood

Back 20

- On dorsum of digits, triangular fibrous expansion

- Distally the expansion divides into central slip (middle phalanx) and two lateral slips (distal phalanx).

- Intricate hand muscles insert here (lumbricals, interossei).

- Lets you do fine motor finger control

Front 21

Extensors/Abductors of the thumb

Back 21

Located deeper in posterior forearm.

1) Abductor pollicis longus
2) Extensor pollicis brevis
3) Extensor pollicis longus

Referred to as outcropping mucsles, help with intricate/precise thumb muscles.

Front 22

Extensor reticulanum

Back 22

All extensors are secured at wrist by it.

Extensor tendons put in 6 compartments, fibro-osseous tunnels.

Surrounded by synovial sheaths that help movement.

Front 23

Ganglion or synovial cyst

Back 23

Thin walled cyst that contain clear synovial fluid on the back of wrist.

Known as bible cysts.

As they get bigger, they can compress nerves causing pain and damage.

Usually on extensor carpi radialis brevis/longus tendons.

Treat by surgically removing.

Front 24

Snuff box

Back 24

Prominent concavity at wrist when thumb is extended.

Bounded by three thumb abductors/extensors.

Radial artery and scaphoid bone can be palpitated at base of box.

Front 25

Nerves of the forearm

Back 25

1) Radial nerves innervate forearm extensor/supinator muscles

2) Median nerve innervates most forearm flexors/pronators

3) Ulnar nerve innervates 1.5 forearm flexors.

Front 26

Radial nerve

Back 26

Divides into superficial (cutaneous hand) and deep branches.

Deep branch pierces supinator and enters extensor compartment where it continues as posterior interosseous nerve. This innervates many forearm extensors.

Front 27

Ulnar nerve

Back 27

Passes by medial epicondyle (common injury site).

Innervates flexor carpi ulnaris. Innervates medial half of flexor digitorum profundis.

Gives off cutaneous branches for medial hand.

Passes through canal of Guyon between hamates and pisiform. This is where nerve compression for cyclists happens.

Innervates most intrinsic hand muscles.

Front 28

Median nerve

Back 28

Main nerve of anterior compartment of forearm.

Passes between two heads of pronator teres,then between FDP and FDS.

Muscular branch/anterior interosseus nerve innervate all flexors except for ulnar 1.5 .

Passes below flexor reticulanum and enters hand.

Lateral palm cutaneous offshoot (palmar branch).

Front 29

Arteries to the forearm (progression, etc)

Back 29

Brachial artery terminates as ulnar and radial arteries.

Several branches provide anastomoses to elbow.

Ulnar artery goes through anterior compartment along ulnar nerve to palm.

Radial artery is smaller. Courses beneath brachioradialis and enters snuff box.

Front 30

Joints of upper extremity

Back 30

1) Elbow joint
2) Radioulnar joint
3) Wrist joint
4) Metacarpophalangeal joints

Front 31

Elbow joint

Back 31

Hinge type synovial joint.

Flexion AND extension.

Trochlea and capitulum articulate with trochlear notch of ulna and head of radius.

Radial collateral ligaments surround weak capsule filled with synovial fluid. This blends with annular ligament of radius.

Front 32

Proximal Radioulnar Joint

Back 32

Pivot type synovial joint.

Annular ligament, lined with synovial membrane, forms ring around the head of radius.

So radius can rotate (supinate/pronate) within annular ligament.

Front 33

Nursemaid's Elbow

Back 33

Dislocate radial head in young kids.

Radial head is small ages 1-3, so that dislocate out of annular ligament. When child is lifted by arm, partially tear that ligament.

Reduction and sling for two weeks does the trick!

Front 34

Radiocarpal (Wrist) joint

Back 34

Condyloid type synovial joint.

Allows for flexion, extension, abduction, adduction, circumduction.

Articulates with 3 proximal carpal bones:

- scaphoid
- lunate
- triquetrum (severe adduction)

Some Lovers Try Positions They Can't Handle.

In this case just first three words.

Radial and ulnar collateral ligaments strengthen joint.

Front 35

Metacarpophalyngeal joints

Back 35

Condyloid type joint.

Three plane movement:
- Flexion/extension
- Abduction/adduction
- Circumduction

Head of metacarpal articulates with base of proximal phalanx.

Collateral ligaments strengthen capsule.

Palmar ligament strengthens anterior aspect of joint.

Deep transverse metacarpal ligament holds heads 2-5 (non-thumb) in place.

Front 36

Game keeper's thumb

Back 36

Rupture of ulnar collateral ligament of the thumb. Ski pole injury. Radially directed force tears ligament.