Unformatted text preview: Foundations of Occupation: Foundations of Occupation: Kinesiology
Lecture 10: The Hand Part II & Lecture 11: Intro to Pinch & Grip Overview Overview Review Intrinsic Finger Muscles Extensor Hood Mechanism Introduction to “The Glove” (in ELL) Movement Perspectives Prehension Patterns Clinical Snapshot… Clinical Snapshot… Elson's Test: Importance of Extensor Hood M (Bring Your Own Toppings!) BYOT BYOT Motions of the Thumb Motions of the Thumb Extension / Flexion with forearm supinated, extend thumb and touch table. Thumb flexion sweeps the palm clean with thumb staying in contact with palm. ABduction / ADduction with forearm in midposition, view hand from radial side with thumbnail and side of index finger visible. Thumb closest to fingers in contact with palm and index finger in adduction. Make an “L” with your left thumb, while keeping thumbnail in view to perform abduction. Opposition movement of thumb from palm to other digits so pads are touching. Review: Extrinsic Muscles Review: Extrinsic Muscles Finger: Flexor digitorum superficialis Flexor digitorum profundus Extensor digitorum Extensor digiti minimi Extensor indicis Thumb: Flexor pollicis longus Extensor pollicis longus Extensor pollicis brevis ABductor pollicis longus Review: Thumb Intrinsics Review: Thumb Intrinsics (Thenar Group) Opponens Pollicis (OP) Abductor Pollicis Brevis (AbPB) Flexor Pollicis Brevis (FPB) Adductor Pollicis (AdP) Review: Opposition and Reposition Review: Opposition and Reposition Activity of OP predominates and acts to ABduct, flex and rotate thumb at CMC simultaneously AbPB further ABducts the CMC joint to open the “jaws of the pincer” wider FPB stabilizes the metacarpal and proximal phalanx in a position that helps maintain opposition (flexes & rotates). FPB works in synergy with AdP (both flex & stabilize rotation) If force is required then: AdP strengthens grip on object FPL will assist for power needed at thumb tip; and/or it will stabilize the thumb along with EPL (both prime movers for aDduction of CMC). Today: Intrinsic Finger Muscles Today: Intrinsic Finger Muscles Hypothenar Muscles Opponens digiti minimi Flexor digiti minimi ABductor digiti minimi Dorsal Interossei Palmar Interossei Lumbricals Hypothenar Eminence Hypothenar Eminence Proximal to 5th digit on the ulnar side of hand. Help to bring 5th digit into opposition and stabilize the 5th digit for grasping.
AbDM + FDM + ODM: Hypothenar eminence Hypothenar Muscles Hypothenar Muscles Abductor Digiti Minimi (AbDM) – “fifth dorsal interossei” Proximal attachment on pisiform and into the tendon of FCU. Distal attachment at base of 5th proximal phalanx and ulnar border of extensor hood (attached to proximal extensor mechanism) Prime Mover: MP Abduction (5th digit) Assists with simultaneous MP flex and IP extension (5th digit) Flexor Digiti Minimi (FDM) Proximal attachment on hamate and flexor retinaculum. Distal attachment on base of proximal phalanx of little finger. Prime mover: MP Flexion (5th digit) Hypothenar Muscles (cont’d) Hypothenar Muscles (cont’d) Opponens Digiti Minimi (ODM) Proximal attachment hamate and flexor retinaculum. Distal attachment on entire length of 5th metacarpal bone (ulnar side). Prime mover: CMC Flexion and Rotation (5th digit) Also slightly rotates the CMC joint of little finger and brings it into alignment for opposition. (only with AbDM and FDM) Dorsal Interossei Dorsal There are 4 dorsal interossei (DI). Middle finger has 2. All cross MCP joints volarly. The DI begin at the index finger. MP aBduction Assist MP Flex/IP Ext (via Dorsal Interossei (cont’d) Dorsal Interossei (cont’d) First DI Proximal attachment from 1st (thumb) metacarpal ulnar side and the 2nd (index finger) metacarpal radial side. Distal attachment base of proximal phalanx of index finger on radial side and into proximal extensor mechanism Easiest to palpate in web space between thumb and index finger. 2nd through 4th DI Proximal attachment on adjacent sides of each metacarpal in each interspace between ED tendons. Distal attachments into proximal (phalanx/hood) and distal (central tendon/lateral bands) extensor mechanism. DI 2 Radial side of proximal phalanx of middle finger with both proximal and distal attachments to extensor mechanism. DI 3 Ulnar side of proximal phalanx of middle finger with both proximal and distal attachments to extensor mechanism. DI 4 Ulnar side of proximal phalanx of ring finger with both proximal and distal attachments to extensor mechanism. Action of Dorsal Interossei Action of Dorsal Interossei Prime movers for aBduction of MCP. Important assists for MCP flexion and IP extension (due to attachments in the extensor hood). AbDM can be considered 5th DI functionally Palmar Interossei Palmar There are 34 PI. The thumb may have one. Middle finger has no palmar interossei. The middle finger does not need a PI since there are 2 DI which function to aBduct it away from midline of hand. Action of Palmar Interossei Prime movers for aDduction of MCPs Important assists for MCP flexion and IP extension. Attachments of Palmar Interossei Attachments of Palmar Interossei 1st PI runs from the base of ulnar side of thumb metacarpal into distal extensor mechanism and into base of first proximal phalanx (ulnar side). 2nd PI – runs from ulnar side of 2nd metacarpal into distal extensor mechanism (ulnar side) of second proximal phalanx. 3rd and 4th PI runs from radial side of metacarpals into distal extensor mechanism on radial side of ring and little finger. Lumbricals Lumbricals There are 4 lumbricals, one at each finger. Deep Transverse Metacarpal Ligament separates the lumbricals from the Palmar Interossei. In general, proximal attachment is the tendon of the FDP; distal attachment on lateral bands of extensor hood on radial side. Only muscles in body that link two other muscle groups together, both proximally and distally. They “float” between FDP and extensor hood. Prime movers for flexion of MCP joint and extension of IP joint. (simultaneously) Extensor Hood Mechanism Extensor Hood Mechanism Clinical Scenario Clinical Scenario
Intrinsic Plus Intrinsic Minus What Would an OT Do??? What Would an OT Do??? Extensor Hood Mechanism Extensor Hood Mechanism Dorsal Hood Mechanism or Extensor Assembly. Includes muscles, tendons, ligaments. Allows for highly coordinated movements of hand. Includes: ED, DI, PI, Lumbricals, Triangular Ligament, and Oblique Retinacular Ligament. Components of Components of Extensor Hood Mechanism Extensor Digitorum needs the EHM to work optimally to not hyperextend MCPs while IPs flex. ED tendon is anchored to the capsule of the MCP and then flattens into the extensor hood. Extensor hood – covers/wraps around proximal phalanx and splits at the head (extends MP joint). Central slip/tendon attaches to base of middle phalanx. Extends the PIP joints. Lateral bands directly responsible for extending DIP. Terminal slip/tendon – inserts on distal phalanges. DIP joint PIP joint MP joint Extensor Hood Mechanism Extensor Hood Mechanism Extensor Hood Mechanism Extensor Hood Mechanism More Components of More Components of Extensor Hood Mechanism Dorsal Interossei prime movers for ABduction of MCP joints. Assist with MP flexion and IP extension due to their attachment on EHM. Palmar Interossei prime movers for ADDuction of MCP joints. Assist with MP flexion and IP extension due to their attachment on EHM. Lumbricals prime movers for IP extension. Remove the passive force of flexor tendon from MCP and IP joints. Triangular Ligament – connects the two lateral bands dorsally at the middle phalanx (just dorsal to the DIP joint). Oblique Retinacular Ligament attaches proximally to the 1st phalanx, ligaments/pulleys and flexor tendon sheath and then runs obliquely to attach to lateral bands, distal to PIP joints. “The Glove” Movement Perspectives Movement Perspectives Finger Extension – Flexion of MCPs with Extension of IPs – Closing of Fist – Opening of Fist Prehension Patterns: Prehension Patterns: Power Grip Features of Power Grip Phases of Power Grip: Open hand Position fingers Approach object Static phase Prehension Patterns: Prehension Patterns: Power Grip (cont’d)
Varieties of Power Grip: Cylindrical Grip – almost exclusively involves use of flexors to carry fingers around and maintain grasp on object Hook – primarily it’s a function of the fingers; may include palm, never includes thumb Spherical Grip – similar to cylinder grip, but with increased spread of fingers to encompass object Lateral Prehension – lateral grip involves the static holding of an object that is then moved by the more proximal joint of the UE Prehension Patterns: Prehension Patterns: Precision Handling Features of Precision Handling Varieties of Precision Handling: PadtoPad – opposition of the pad of the thumb to the pad of a finger TiptoTip – like padtopad, but IP jt of finger & thumb must have range & available muscle force to produce nearly full jt flexion PadtoSide – “key grip” or lateral pinch; key held btn pad of the thumb & side of finger; least precise of precision handling Variation During Occupation… Variation During Occupation… http://dopejam.multiply.com/video/item/6 http://www.youtube.com/watch?v=jX6Td47d78 ...
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This note was uploaded on 09/02/2010 for the course OT 440 taught by Professor Rafeedie during the Fall '10 term at USC.
- Fall '10