Anatomy-Wrist and Hand Flashcards
What bones are found in the hand?
- 8 carpals
- 5 metacarpals
- 14 phalanges (thumb only has 2)
What are the names of the 8 carpals?
- Proximally: scaphoid, lunate, triquetrum, pisiform
- Distally: hamate, capitate, trapezoid, trapezium
What carpal bones articulate with the radius?
-The proximal carpal bones form a convex surface which articulates with the concave surface of the articular disk and radius.
What does the fascia do?
-Holds tendons, blood vessels and nerves close to bones
What fascia is at the wrist and what are its properties?
- Retinaculum
- A thick deep fibrous band
- Holds tendons down and prevents bowstringing
What types of retinacula are in the wrist?
- Flexor retinaculum: over anterior carpal bones (flexor tendons and median nerve pass under)
- Extensor retinaculum: on dorsal carpal bones (extensor tendons of hands and digits pass under)
What forms the roof of the carpal tunnel?
-Flexor retinaculum attatched to; scaphoid and trapezium, pisiform and hamate.
What forms the floor of the carpal tunnel?
-Concave arch of carpal bones (covered by extrinsic palmar ligaments)
What are the contents of the carpal tunnel?
- 4 tendons of flexor digitorum profundus
- 4 tendons of flexor digitorum superficialis
- Tendon of flexor pollicis longus
- Vascular synovium
- Median nerve (superficial to tendons)
What movements can the thumb do?
- Between the trapezium and base 1st metacarpal:
- abduction -adduction -extension -flexion -opposition -reposition
What movements can the hand do?
- Non prehensile movements: pushing, hitting (with flat hand)
- Prehensile movements: grasp and grip, dependant on positioning of fingers
Explain power grip and the muscles involved?
- Grasped in palm
- Allows holding of tool or punching
- Strong
- Long extrinsic flexors of fingers and intrinsic muscles in palm
- Wrist extended
Explain precision grip and the muscles involved?
- Allows fine control of manipulative movements
- Grip between tips of fingers and thumb (opposition)
- Involves hold by extrinsic flexors and extensors (precision from intrinsic muscles)
What movements can occur between the radius and the carpals?
- Abduct
- Neutral
- Adduct
- Extend
- Neutral
- Flex
What are the metacarpophalangeal joints and what movements occur here?
- Between metacarpals and proximal phalanges
- Flex/extend (wave bye)
- Abduct/adduct (move fingers apart/back)
What are the interphalangeal joints and what movements do they do?
- Proximal IP joint = between proximal and middle phalanges
- Distal joint = between middle and distal phalanges
- Flex/extend: curl and straighten digits
What groups can the muscles that move the hand, wrist and muscles be separated into?
-Intrinsic: belly inside palm (intricate movements and precision grip)
-Extrinsic: long flexors and extensors, belly outside hand.
Important in power grip
Tendons enter hand deep to retinaculi
Traverse digits in fibrous sheath
What are the superficial extrinsic flexors of the fingers?
- Palmaris longus
- Flexor digitorum superficialis
What are the deep extrinsic flexors of the fingers?
- Flexor digitorum profundus
- Flexor pollicis longus
What are the superficial extrinsic extensors of the fingers?
- Extensor digitorum
- Extensor digiti minimi
What are the deep extrinsic extensors of the fingers?
-Extensor indicis
What are the extrinsic muscles of the thumb?
- Flexor pollicis longus (ant.)
- Extensor pollicis longus (post.)
- Extensor pollicis brevis (post.
- Abductor pollicis brevis (post.)
What is the anatomical snuffbox?
A key landmark for physical examination.
-Triangular deepening on radius dorsal hand.
What forms the floor of the anatomical snuffbox?
-scaphoid and trapezius bones
What binds the anatomical snuffbox?
- Tendon of extensor pollicis longus medially
- Tendons of extensor pollicis brevis and abductor pollicis longus laterally
- radial styloid process proximally
- 1st CMC joint distally
What are the 4 groups of intrinsic finger muscles?
- Thenar
- Hypothenar
- Lumbricals
- Interossei
What supplies the intrinsic finger muscles?
-Ulnar and radial
What are the muscles of the hypothenar eminence?
- Abductor digiti minimi
- Flexor digiti minimi
- Opponens digiti minimi
What are the muscles of the thenar eminence?
- Abductor pollicis brevis
- Flexor pollicis brevis
- Opponens pollicis
What are the lumbrical muscles?
-4 deep muscles
Where are the interossei located?
- 3 on palmar side
- 4 on dorsal side
