Clinical Anatomy and Biomechanics - Elbow, Wrist, and Hand Flashcards
Joints of the Elbow, Wrist, and Hand:
- Name these joints (A-D) = ?
Anatomy & Biomechanics - E,W,H
Bony Anatomy -
Joints of the Elbow, Wrist, and Hand:
(a) Humeroulnar Joint
- Convex: Humerus
- Concave: Olecranon Fossa of Ulna
(b) Humeroradial Joint
- Convex: Capitulum of the Humerus
- Concave: Radial Head
(c) Proximal Radioulnar Joint
- Convex: Radial Head
- Concave: Ulna
(d) Distal Radioulnar Joint
- Convex: Ulna
- Concave: Radius
Joints of the Elbow, Wrist, and Hand:
- Name these joints (E-I) = ?
Anatomy & Biomechanics - E,W,H
Bony Anatomy -
Joints of the Elbow, Wrist, and Hand:
(e) Radiocarpal Joint
- Convex: Carpals (S, L, T)
- Covcave: Distal Radius
(f) Midcarpal Joint
(g) Carpometacarpal Joint
(h) Metacarpophalangeal Joint
(i) Interphalangeal Joint
Humeroulnar Joint - Trochlea and Trochlear Notch:
- Helps Guide = ?
- Valgus movement = ?
- Varus movement = ?
Anatomy & Biomechanics - E,W,H
Humeroulnar Joint: Trochlea and Trochlear Notch
(a) Helps Guide = Flexion & Extension
(b) Dictates Valgus vs Varus Movements
- Valgus = Elbow Extension
- Varus = Elbow Flexion
(c) Does not follow Concave-on-Convex Rules
(d) Deep Concavity Restricts:
- Traditional Distraction
- Solution = 45°
- Traditional Concave-on-Convex Arthrokinematic Glide
- Solution = Posterior Medial/Lateral at 60°
Humeroulnar Joint - Capitulum and Radial Head:
- Helps Guide = ?
- Extension and _ go together = ?
- Flexion and _ go together = ?
Anatomy & Biomechanics - E,W,H
Humeroulnar Joint - Capitulum and Radial Head:
(a) Helps Guide:
- Flexion and Extension
- Pronation and Supination
(b) Follows Traditional Concave-on-Convex Rules
(c) Dictates Length of Radius:
- Posterior-medial Radial Head is thicker
- In Pronation, it pushes the radius distally
(d) Synkinetic with PRUJ:
- Extension and Pronation go together
- Flexion and Supination go together
Proximal Radioulnar Joint - Radial Head and Radial Notch:
- Helps Guide = ?
- Radius resides _ to the Ulna = ?
- Pronation and _ go together = ?
- Supination and _ go together = ?
Anatomy & Biomechanics - E,W,H
Proximal Radioulnar Joint - Radial Head and Radial Notch:
Radial Head and Radial Notch
(a) Helps Guide = Pronation and Supination
(b) Follows Traditional Convex-on-Concave Rules
(c) Radius Resides Anterior to the Ulna
- For Posterior-Lateral, follow the 60° (like the ulna)
- PRUJ & DRUJ have opposite concavities/convexities
(d) Synkinetic with Humeroradial Joint:
- Pronation likes Extension
- Supination likes Flexion
Distal Radioulnar Joint:
- Helps Guide movement and forces.
- Most Congruent = ?
- Least Congruent = ?
Anatomy & Biomechanics - E,W,H
Distal Radioulnar Joint:
(a) Helps Guide Movement and Forces:
- Pronation and Supination
- Distal Radius Transmits 80%
- TFCC Absorbs 20%
(b) Follows Traditional Concave-on-Convex Rules
(c) PRUJ & DRUJ have opposite concavities/convexities
(d) Most/Least Congruent
- Least = Pronation
- Most Congruent in Supination
(e) Disrupted by:
- Colles’ Fracture
- Malalignment and Radioulnar Ligament Dysfunction
- Ulnar Styloid Fracture
- Radioulnar Ligament Dysfunction
Carpals:
- Proximal Transverse Arch provides space for = ?
- Intrinsically Stabilized by = ?
- Arthrokinematics: Radiocarpal is = ?
- Arthrokinematics: Mid-Carpal is = ?
Anatomy & Biomechanics - E,W,H
Carpals:
(a) Proximal Transverse Arch provides space for:
- Muscular Structures
- Neurovascular Structures
(b) Intrinsically Stabilized by:
(1) Form Closure (Primary)
- Interlocking ‘S’ Shape (Prone to Ant/Post Instability)
(2) Force Closure (Secondary)
- Only Flex. Carpi Ulnaris and Thenar Muscles
(c) Arthrokinematics:
- Radiocarpal is Convex-on-Concave
- Mid-Carpal does not follow Traditional Rules
- Scapholunate Angle is 30-60° Palmar
CMC Joints
- Trapeziometacarpal (CMC 1), what kind of joint = ?
Anatomy & Biomechanics - E,W,H
CMC Joints:
(a) Trapeziometacarpal (CMC 1)
- Saddle Joint
- Concave-on-Convex in Flexion and Extension
- Convex-on-Concave in Abduction and Adduction
(b) CMC Joints 2 & 3
- Affixed with limited movement
(c) CMC Joints 4 & 5
- Complex Planar Joint
- Allows flexion and extension of metacarpals 4 & 5
MCP & IP Joints:
- Metacarpophalangeal Joints (MCP), what kind of joint = ?
- Interphalangeal Joints (IP), what kind of joint = ?
Anatomy & Biomechanics - E,W,H
MCP & IP Joints:
(a) Metacarpophalangeal Joints (MCP)
- Condyloid Joints
- Concave on Convex
(b) Interphalangeal Joints (IP)
- Hinge Joints
- Concave on Convex
Innervation of the Wrist and Hand:
- Median n. sensation and compression = ?
- Radial n. sensation and compression = ?
- Ulnar n. sensation and compression = ?
Anatomy & Biomechanics - E,W,H
Innervation of the Wrist and Hand:
(a) Median:
- Sensation: Palmar and Dorsal-Distal 1-3rd
- Proximally Compressed at the Pronator Teres
- Distally Compressed at the Carpal Tunnel
(b) Radial:
- Sensation: Dorsal 1-3rd
- Proximally Compressed at Radial Tunnel between the two heads of the Supinator
(c) Ulnar:
- Sensation: Dorsal and Palmar 4th and 5th
- Proximally Compressed at the Cubital Tunnel
- Distally Compressed at Guyon’s Canal
Anterior vs Posterior Interosseous Syndrome:
- Anterior interosseous syndrome, entrapment of what nerve = ?
- Presents with = ?
Anatomy & Biomechanics - E,W,H
Anterior vs Posterior Interosseous Syndrome:
(a) Anterior Interosseous Syndrome:
- Entrapment of the Median Nerve
- Two Heads of Pronator Teres
(b) Motor Nerve
- Flexor Pollicus Longus
- Flexor Digitorum Profundus (2&3)
- Pronator Quadratus
(c) Presentation
- No Sensory Loss
- Weakness of Tip Pinch Grasp
- Unable to Make “Okay” Sign
- Unable to Button Shirts
- Possible Pain at Proximal, Medial Forearm
Anterior vs Posterior Interosseous Syndrome:
- Posterior interosseous syndrome, entrapment of what nerve = ?
- Presents with = ?
Anatomy & Biomechanics - E,W,H
(a) Posterior Interosseous Syndrome:
- Entrapment of the Radial Nerve
- Radial Tunnel – Supinator
(b) Motor Nerve:
- Supinator
- ECRB
- Extensor Digitorum
- Extensor Digiti Minimi
- ECU
- Abductor Pollicis
- Extensor Pollicis Brevis/Longus
- Extensor Indicis
(c) Presentation
- No Sensory Loss
- Weakness in MCP Extension, Some Wrist Ext.
- Possible Pain at the Radial Tunnel
Intrinsic Muscles - Foundational Testing:
- Lumbricals are on what side = ?
- Interossei attach on the side = ?
Anatomy & Biomechanics - E,W,H
Intrinsic Muscles - Foundational Testing:
Clinical Pearls:
(a) Lumbricals are on the Thumb Side:
- Merge off the Profundus to keep mechanical advantage of flexion
(b) Interossei attach on the side needed to perform their function:
- (4) Dorsal Abduction
- (3) Palmar Adduction
Anatomy & Biomechanics - E,W,H
