Forearm&Hand + Cutaneous Innervation

upper limb dermatomes

-regions of skin that correspond to 1 spinal nerve; single spinal nerve providing sensory

-adjacent dermatomes overlap

-more conceptual than physical

Cutaneous innervation: axillary N.

-C5, C6

-post and lateral shoulder

Cutaneous innervation: musculucutaneous nerve

→ lateral antebrachial cutaneous nerve

Cutaneous innervation: radial nerve

posterior arm, forearm, and hand

Cutaneous innervation: median nerve

lateral hand palmar side, nail beds 1-3, ~4

Cutaneous innervation: ulnar nerve

-medial hand pamlar and dorsal

cutaneous innervation: limb overview

cutaneous innervation of hand

-parashesia were no overlap

structures at the wrist

-Extensor retinaculum: keeps tendosn in place

-Palmar carpal ligament: continuous with extensor retinaculum

-Flexor retinaculum/transverse carpal l: forms part of carpal tunnel

 retinacula

•The retinacula are like a bracelet

•Specialized parts of deep fascia

•Creates tunnels for tendons / other structures

•Holds tendons in place to create lever system for wrist

Extensor retinaculum: attachment + tunnel for…

Attaches at:

–pisiform, hook of hamate, AND the distal end of the radius

Tunnel for, lateral to medial, the tendons of:

1.abductor pollicis longus and extensor pollicis brevis muscles

2.extensor carpi radialis longus and brevis muscles

3.extensor pollicis longus muscle

4.extensor digitorum and extensor indicis muscles

5.extensor digiti minimi muscle

6.extensor carpi ulnaris muscle

*”Adults Believe, Children Citerently, Love, Do Infects, Make Us”

Flexor retinaculum: attaches to + tunnel for…

Attaches to:

•pisiform bone and hook of hamate bone (medially)

•tubercles of scaphoid and trapezium bones (laterally)

Forms a tunnel for 10 things: (carpal tunnel)

•4 tendons of the flexor digitorum superficialis m.

•4 tendons of the flexor digitorum profundus m.

•tendon of the flexor pollicis longus m.

•median nerve

Dorsal Hand: Extensor Digitorum muscle

-acts on all IP; to distal phalanx

-Extensor Expansion: dorsal; place where the single tendon of extensor digitorum divides

Palmar Hand: Flexor Digitorum Superficialis and Profundus

different insertions so different actions…

-FDS: tendon splits, FDP tendon pass through it; insert middle phalanx and flex PIP

-FDP: inserts on distal phalanx so flexes PIP and DIP

-+Annular ligament circular, cruciate component x

tendon for extensor digitorum + lumbricals

carpal tunnel

-Cylindrical space tendons and median nerve pass through

Boundaries

-Floor: Hamate, capitate, trapezoid

-Medial wall: Hamate

-Lateral wall: Trapezium

-Roof: Hook of hamate, flexor retinaculum attached to trapezium (*retinaculum rigid)

Content

-10 contents=4 tendons FDS, 4 tendons FDP, tendon Flexor Pollicis Longus, median n

Injury

-inflammation or overuse impose on median n

-Phalen’s test or Tinel’s test reproduce symptoms

Radial foveola

-A depression found on lateral surface of wrist

Boundaries:

-Medial: by tendon of extensor pollicis longus muscle

-Lateral: by tendons of abductor pollicis longus and extensor pollicis brevis muscles

Structures palpated:

• Radial artery

• radial styloid process

• 1st metacarpal bone

Why care?

-radial pulse

-Test for inflammation of tendons due to repetitive stress / infection (de Quervain tenosynovitis)= “Finkelstein Test”

-Palpate the scaphoid for fracture: most commonly fractured, not always on x-rays; interrupt blood supply to bone if fracture → sepsis

what type of joint is the radiocarpal joint? what bones make up the joint?

condyloid joint

-radius + schapoid, lunate, and triquetrum

motions of the wrist joint

•Flexion

•Extension

•Adduction

•Abduction

•Circumduction

–This is a combination of the others

muscle table: wrist flexion and extension

muscle table: wrist adduction and abduction