The Hand Flashcards
What classification of joint are the carpometacarpal joints?
Thumb - Synovial saddle
Digits - Synovial plane
What movement does the saddle joint of the thumb allow?
Opposition
Unique to humans and forms the basis for precision grips
What joint classification are the metacarpalphalangeal joints and what movements occur here?
Synovial condyloid
Flexion, extension, abduction, adduction and a small degree of circumduction
What joint classification are the interphalangeal joints and what movements are seen?
Synovial hinge
Flexion and extension
What muscle is shown and what is its innervation?
Palmaris Brevis
Ulnar nerve
What is the role of the palmaris brevis muscle?
Tightens the palmar aponeurosis to enhance grip
What are intrinsic and extrinsic muscles of the hand?
Intrinsic = muscles entirely within the hand Extrinsic = muscles that enter the hand from the forearm
What are the 3 intrinsic muscles of the thenar eminence?
Flexor pollicis brevis
Abductor pollicis brevis
Opponens pollicis
What is the muscle and its innervation?
Flexor pollicis brevis
Recurrent branch of median nerve
(Ulnar in some texts)
What are the attachments of flexor pollicis brevis?
Flexor retinaculum, capitate and trapezium
To base of proximal phalanx of thumb
What movement does flexor pollicis brevis carry out?
Flexion of the thumb CMC
What muscle is highlighted and what is its innervation?
Abductor pollicis brevis
Recurrent branch of median nerve
What are the attachments of abductor pollicis brevis?
Scaphoid and Trapezium
To base of the proximal phalanx of the thumb
What is the action of abductor pollicis brevis?
Thumb CMC abduction
What muscle is highlighted and what is its innervation?
Opponens pollicis
Recurrent branch of median nerve
What are the attachments of opponens pollicis?
Trapezium to the 1st metacarpal
What is the action of opponens pollicis?
Opposition of CMC of thumb
What muscle is highlighted and what is its innervation?
Adductor Pollicis
Ulnar nerve
What are the attachments of adductor pollicis?
Transverse head from 3rd metacarpal
Oblique head from 2nd/3rd metacarpals
To base of proximal phalanx of thumb
What are the movements of adductor pollicis?
Adduction of CMC joint of thumb
Flexion of MCP of thumb
What are the 3 muscles of the hypothenar eminence?
Abductor digiti minimi
Flexor digiti minimi
Opponens digiti minimi
What muscle is highlighted and what is its innervation?
Abductor digiti minimi Ulnar nerve (deep)
What are the attachments of abductor digiti minimi?
Pisiform bone
To base of 5th proximal phalanx and dorsal digital expansion
What are the actions of abductor digiti minimi?
Abduction and flexion of MCP joint little finger
What muscle is highlighted and what is its innervation?
Flexor digiti minimi Ulnar nerve (deep)
What are the attachments of flexor digiti minimi?
Hamate and flexor retinaculum
To base of 5th proximal phalanx
What are the actions of flexor digiti minimi?
Flexion of little finger MCP joint
What is the muscle and its innervation?
Opponens digiti minimi Ulnar nerve (deep)
What are the attachments of opponens digiti minimi?
Hamate and flexor retinaculum
To 5th metacarpal
What are the actions of opponens digiti minimi?
Weak opposition of little finger
What is the name of these muscles?
Lumbricles
Where do the lumbricles originate from?
The tendons of flexor digitorum profundus
What are the shapes of the lumbricles?
1st (index) and 2nd (middle) = unipenate
3rd (ring) and 4th (little) = bipennate
Where do the lumbricles insert?
The dorsal digital expansion
What are the actions of the lumbricles?
MCP joint flexion
IP joint extension
(digits 2-4)
What is the innervation of the lumbricles?
1st and 2nd= Median nerve (digital branch)
3rd and 4th= ulnar nerve (deep branch)
What are the muscles shown and what is their innervation?
Palmar interossei Ulnar nerve (deep branch)
What are the attachments of the palmar interossei?
Base of proximal phalanxes and digital expansions
What are the actions of the palmar interossei?
Adduction towards the middle finger
flexion of MCP and extension of IP
What muscles are shown and what is their innervation?
Dorsal interossei Ulnar nerve (deep)
What is the action of the dorsal interossei?
Abduction
MCP flexion and IP extension
What is the origin of the dorsal interossei?
From the sides of 2 adjacent metacarpals
e.g. the first dorsal interossei originates from 1st and 2nd metacarpals
What are the insertions of the dorsal interossei?
Proximal phalanxes and digital expansions
What arteries supply the hand?
Radial and ulnar
Anastomose to supply the hand
Describe the arterial arches of the hand
Superficial arch is mostly formed by the ulnar artery
Deep arch is mostly formed by the radial
Why do the digital branches of the arteries lie on the lateral aspects of the digits?
To prevent damage to the vessels during flexion and extension of the digits
In relation to the carpal tunnel, where does the ulnar artery lie?
Crosses to the wrist above the carpal tunnel
On the floor of which anatomical structure does the radial artery lie?
The anatomical snuffbox
Describe the path taken by the radial artery from the forearm to hand
Passes through the anatomical snuffbox (over scaphoid and trapezium) into the hand
Passes between the heads of adductor pollicis to anastamose with the ulnar artery
What is the largest arterial vessel to the thumb and from what artery does it arise?
Princeps Pollicis
Arises from the radial artery
What is the clinical significance of the thenar and hypothenar spaces of the hand?
Can be important in tracking infection across the palm of the hand
What nerve dominates the lateral side of the hand?
Median nerve
What nerve dominates the medial side of the hand?
Ulnar
