Wrist and Hand - Bones, Joints and Muscles Flashcards
What is the structure of the wrist joint?
- The Radiocarpal joint is biaxial
- The Radioulnar joint has a smooth concavity while the carpals create a convexity
- This enables the wrist to create Radial and Ulnar Deviation
What bones create the Radiocarpal joint?
- Radius (NOT ULNA)
- Scaphoid (Medial)
- Lunate
- Triquetral articulates with the disc*
What are the 5 significant ligaments of the wrist?
- Radioulnar Ligament
- Medial Collateral O = Ulnar Styloid I = Triquetral and Hamate
- Lateral Collateral O = Radial Styloid I = Scaphoid and Trapezium
- Dorsal Radiocarpal
- Palmar Radiocarpal
What are the 5 flexors of the forearm? PFPFF
What is the CFO?
What are the insertions?
CFO is the Common Flexor Origin which is the on the Medial Epicondyle. All these muscles originate in this area.
- Pronator Teres: I = Lateral surface of Radius
- Flexor Carpi Radialis: I = Bases of 2nd & 3rd metacarpals
- Palmaris Longus: I = Apex of Palmar Aponeurosis
- Flexor Digitorum Superficialis: O = Anterior Radial Border I = Interphalangeal joint of digits 2-5
- Flexor Carpi Ulnaris: I = Pisiform, Hamate and 5th metacarpal
What are the 2 deep flexors of the forearm and what are their insertions?
- Flexor Pollicis Longus: O = Medial side of Radius and Interosseous membrane I = Base of distal phalanx of thumb
- Flexor Digitorum Profundus: O = Shaft of Ulna and Interosseous membrane I = Base of distal phalanx of digits 2-5
What are the Pronator muscles of the forearm and what are their insertions?
- Pronator Teres: O = CFO I = Lateral surface of Radius
- Pronator Quadratus: O = Medial aspect of Ulna I = Lateral aspect of Radius
What are structures associated with the flexor tendons?
- Flexor retinaculum (Carpal Tunnel)
- Synovial Sheaths of the flexor tendons; to prevent inflammation from friction
What are the 8 carpal bones?
*What carpal bones are apart of Radiocarpal?
^What carpal bones are apart of the Midcarpal joint?
- *Scaphoid (Medial)
- *Lunate
- *Triquetral (Lateral)
- ^Trapezium (Medial)
- ^Trapezoid
- ^Capitate
- ^Hamate
- ^Pisiform
Name the 3 arches of the hand and what is the purpose of it?
- Fixed Transverse Arch (Flexor Retinaculum)
- Mobile Longitudinal Arch (Flexor R to D3)
- Mobile Oblique Arch (D5 to D1)
Having arches, in a relaxed position, allows the hand to be naturally read for grasping and gripping an object.
What movements are involved at the midcarpal and radiocarpal joint?
Percentage and degrees
Flexion: 60% Radiocarpal 50-60°, 40% Midcarpal joint 35-40°
Extension: 40% Radiocarpal 35-40°, 60% Midcarpal joint 50-55°
Ulnar Deviation: Radiocarpal 30-35°, Midcarpal 15-20°
Radial Deviation: Equal contribution 15°
What are carpals attaching to each metacarpal?
Digit 2: Trapezoid
Digit 3: Capitate
Digit 4: Hamate
Digit 5: Hamate
What type of joint is the metacarpophalangeal joint?
Biaxial Condylar joint - Metacarpal heads are convex and the phalanges are concave
What ligaments are involved in the metacarpophalangeal joints?
- Medial Collateral ligament
- Lateral Collateral ligament
- Deep transverse ligament
- Volar Plate
What is the purpose of Volar Plate?
A plate of cartilage which surfaces the anterior palmar region of the MCP joints, lined for articulation; longer concavity
What type of joint is the Interphalangeal joints?
- Simple Hinge joint
- Smaller Volar plates
What is the carpal and type of joint of the 1st Carpometacarpal joint?
- Attachment to the Trapezium
- Saddle joint: multiaxial
What 3 ligaments are associated with the thumb?
- Radial Carpometacarpal ligament (Lateral)
- Anterior and Posterior Oblique ligaments (Lateral on carpal, Medial on metacarpal)
What movements are possible at the thumb?
Flexion and Extension (Towards palm)
Abduction and adduction (To and Away from Knuckles)
Opposition (Pad of thumb to fingers)
What muscles are in the superficial layer which extend the wrist? What is CEO? 3 Wrist 3 Fingers
CEO is the Common Extensor Origin is the Lateral Epicondyle
- Extensor Carpi Ulnaris: I = Base of 5th metacarpal
- Extensor Carpi Radialis Longus: I = Base of 2nd metacarpal
- Extensor Carpi Radialis Brevis: I = Base of 3rd metacarpal
- Extensor Digitorum: I = Splits to base of the proximal phalanx of digits 2-5
- Extensor digiti minimi: I = Digital expansion of 5th digit
- Extensor indicis: O = Posterior surface of Ulna I = Dorsal Digital Expanison of 2nd digit
What are the actions of the superficial layer of muscles coming from the CEO?
- Extensor Carpi Ulnaris: Ulnar Deviation and extension
- Extensor Carpi Radialis Longus and Brevis: Radial Deviation and extension
What is the Dorsal Digital Expansion?
The extensor ‘hood’ supplies attachment for lumbricals and interossei and stabilises the tendon in midline of the finger
What are the deep extensors of the wrist and what are their insertions? 3 Thumb
- Extensor Pollicis Longus: O = Lateral aspect of the Ulna; middle I = Base of distal phalanx
- Extensor Pollicis Brevis: O = Posterior surface of Radius I = Base of proximal of the thumb
- Adductor Pollicis Longus: O = Posterior surface of Ulna and Radius I = Radial side of base of 1st metacarpal
What are the actions of the deep extensor muscles of the wrist?
- Extensor Pollicis Longus and Brevis: Extension and assists in abduction of wrist
- Adductor Pollicis Longus: Keeps thumb in midrange
What are the insertions and actions of the supinator?
Origin: CEO, Annular ligament and Supinator crest (Ulna)
Insertion: Anterior, Lateral, and Posterior aspects of Radius
Actions: Supinate forearm to lie the Radius laterally
What are the 4 intrinsic muscles of the hand and what are their insertions?
- Flexor Pollicis Brevis: O = Trapezium and Scaphoid I = Midline of proximal phalanx
- Abductor Pollicis Brevis: O = Trapezium I = Base of proximal phalanx laterally
- Adductor Pollicis: O = Capitate, and 2nd & 3rd metacarpal I = Base of proximal phalanx medially
- Opponens Pollicis: O = Trapezium I = Radial border of 1st metacarpal
What are the muscles in the Hypothenar eminence? 5th digit
- Abductor Digit Minimi: O = Pisiform I = Base of proximal phalanx 5th digit
- Flexor Digiti Minimi Brevis: O = Hamate I = Midline of base of proximal phalanx
- Opponens Digiti Minimi: O = Hamate I = Lateral Border of metacarpal
What are the function and insertions of interossei of the hand? PAD NAD
- Palmar Interossei: 3 muscles which originate of metacarpal which rise to the proximal phalanges. ADDUCT TOWARDS 3rd DIGIT
- Dorsal Interossei: 4 muscles which originate laterally on base of metacarpals and rise to proximal phalanges ABDUCT AWAY FROM 3rd DIGIT
What are the lumbricals of the hand and what are their insertions and action?
- There are 4 lumbricals for digits 2–>5
- Rising from Flexor Digitorum Profundus Tendons
- Move obliquely to the Dorsal Digital Expansions
Actions: Flex the MCP and stimultaneously extending proximal and distal Phanlangeal joints
What protects the hand from trauma of tendons?
Palmar Aponeurosis
What is the definition of Synergistic muscle action?
Muscle which is active to limit the action of the prime mover over moving joints.
eg Someone hold a heavy object, Bicep Brachii prime mover, Brachalis preventing complete flexion at the elbow
What is the definition of Co-ordination Fixator muscle action?
Isometric contraction of the antagonistic pair to hold the joint in place
- Holding heavy weight in a fixed position
