Lecture 13 - Hand Flashcards
What nerves innervate the dorsal hand and what portions of the hand do they innervate?
Radial:
- dorsolateral hand
- dorsal thumb
- dorsal proximal second and third digits
Median:
- distal dorsal second and third digits (exclusive)
- distal dorsal fourth digit
Ulnar:
- dorsomedial hand
- dorsal proximal third digit
- dorsal fourth digit
- dorsal fifth finger (exclusive)
What nerves innervate the palmar hand and what portions of the hand do they innervate?
Median:
-central palm
Ulnar:
-medial palm
What are the joints in the hand?
Carpometacarpal joints
Metacarpophalangeal joints
-MCP
Interphalangeal joints
- proximal interphalangeal (PIP)
- distal interphalangeal (DIP)
What type of joint are the carpometacarpal joints and what movements do they allow?
(slide 7)
Type:
-plane, synovial joint
Movement:
- digits 2-3; almost none
- digit 4; limited
- digit 5; ab/adduction, flexion/extension, circumduction
What type of joint are the metacarpophalangeal joints and what movements do they allow?
What ligaments are present
(slide 8)
Type:
-condyloid, synovial
Movement:
- flexion/extension
- abduction/adduction
Ligaments:
- palmar ligaments
- collateral ligaments
Why can you not spread your fingers while they are flexed?
-collateral ligaments are taut during flexion preventing it
What type of joint are the interphalangeal joints and what movements do they allow?
What ligaments are present?
(slide 9)
Type:
-hinge, synovial
Movement:
-flexion/extension
Ligaments:
-collateral ligaments
What are the superficial palmar structures?
slides 11
Palmar aponeurosis
Flexor retinaculum
Palmaris brevis
Describe the palmar aponeurosis.
- triangular layer of deep fascia
- protects for superficial vessels, nerves, and tendons
- anchored to skin by flexor retinaculum
- spilt into 4 sheaths which blend into flexor sheaths of digits 2-4
Describe the flexor retinaculum.
- laterally attaches to tubercles of scaphoid and trapezium
- medially attaches to hook of hamate and pisiform
Describe the carpal tunnel.
- groove between pisiform and hook of hamate
- roof is flexor retinaculum
Contains:
- tendon of flexor digitorum superficialis
- tendon of flexor digitorum profundus
- tendon of flexor pollicis longus
- median nerve
What passes through Guyon’s canal?
- ulnar nerve
- ulnar artery
What are the intrinsic muscles of the thumb?
- abductor pollicis brevis
- flexor pollicis brevis
- opponens pollicis
- adductor pollicis
Of the intrinsic muscles of the thumb, which muscles are part of the thenar eminence?
Other than this, what differentiates these muscles?
Thenar eminence:
- innervated by MEDIAN nerve
- abductor pollicis brevis
- flexor pollicis brevis
- opponens pollicis
Not:
- innervated by ULNAR nerve
- adductor pollicis
What are the intrinsic muscles of the fifth digit?
What is the common innervation?
What structure do these muscles form?
Muscles:
- abductor digiti minimi
- flexor digiti minimi brevis
- opponens digiti minimi
Innervation:
-ulnar nerve
Hypothenar eminance
What are the thenar and midpalmar spaces?
Thenar:
-area between the adductor pollicis muscle and the long flexor tendons of the index finger/thumb
Midpalmar:
-area between metacarpals 4-5 and long flexor tendons to digits 4-5
What path does he radial artery take through the wrist and hand?
- lies lateral to the tendon of the flexor carpi radialis (radial pulse)
- passes across scaphoid in anatomical snuff box
- wraps around dorsum of the first metacarpus
- pierces first dorsal interosseous muscle into the palm of the hand
- forms deep palmar arch
What vessels supply the dorsum of the hand?
Slide 35
Arteries:
- dorsal arterial arch (radial and ulnar arteries)
- dorsal metacarpals
- dorsal digitals
Venous:
-dorsal venous arch (medially to basilic vein and laterally to cephalic vein)
Lymphatic:
-medial through lymph nodes accompanying basilic vein (to subtrochlear and lateral axillary nodes)
What is the arterial supply to the palmar hand?
- superficial palmar arch (continuation of ulnar artery)
- deep palmar arch (continuation of radial artery)
What path does the ulnar nerve take in the hand?
- enters superficial to flexor retinaculum
- branches into superficial branch and deep branch
Superficial branch:
- innervates palmaris brevis
- cutaneous innervation
Deep branch:
-innervates other muscles innervated by ulnar nerve
What path does the ulnar nerve take in the hand?
- enters deep to flexor retinaculum
- divides into lateral and medial branches
What is mallet finger?
Slide 40
- avulsion of long extensor tendon
- results in hyper flexion of DIP
What is Dupuytren’s contracture?
Slide 40
- progressive fibrosis of palmar aponeurosis
- marked flexion of fingers at MP joints
What is Colle’s fracture?
-fracture of distal end of the radius
What results from median nerve injury?
- loss of thumb opposition
- atrophy of thenar muscles
- ape hand
What results from ulnar nerve injury?
- paralysis of interossei (guttering)
- loss of thumb adduction
- claw hand
What are the components of the extensor mechanism and what is its function?
Components:
- hood
- lateral bands (bases of distal phalanges)
- central bands (bases of middle phalanx)
Function:
- flexion at MCP joint
- extension at PIP and DIP joints
