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92 Cards in this Set
- Front
- Back
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What different grips can the hand do?
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Hook grip (as in grabbing a bar)
pinch grip (as in pinching) also (also known as?) - power grip and precision grip |
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Creases of the hand
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pip, DIP, palmar digital crease (at MCP joints)
Distal palmar crease proximal palmar crease - Middle Thenar crease (by thumb) IP MCP wrist creases |
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Fascia of the hand
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superficial fascia
Flexor retinaculum Extensor Retinaculum Palmar aponeurosis |
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Superficial fascia of the hand - dorsal and palmar surfaces
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Dorsal surface - Loose and thin subcutaneous tissue
Fascia helps to keep tendons in place and prevent “bowstringing” Palmar surface: Subcutaneous tissue developed into fibrous pad for grasping Continuation of the volar fascia Helps keep tendons in place Aids with gripping objects |
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Extensor retinaculum - attachments and purpose
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Attachments:
Anterior Radius Triquetrium and Styloid Process of the Ulna Purpose: Secure the extensor tendons in their proper position |
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Flexor Retinaculum - attachments and purpose
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Attachments:
Scaphoid, Triquetrium and Pisiform Purpose: Forms the carpal tunnel Passage of the long finger flexors and median nerve through the tunnel |
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Palmar Aponeurosis
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Triangular shaped fascia
Anchored to the Flexor Retinaculum Continuous with the Palmaris Longus Overlies the flexor tendons to the 4 fingers Defines the Central Compartment of the palm |
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Dupuytren's contracture
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Contracture of the Palmar Aponeurosis causing retraction of the long flexor tendons
Progressive condition of unknown etiology Genetic (Viking ancestry) Disease of palmar fascia resulting in progressive shortening, thickening, and fibrosis of palmar fascia and aponeurosis Fibrosis most easily affects lateral bands to fingers 4 & 5 which pulls them into flexion Mainly at MCP and PIP jts Rx often involves surgical excision of that part of fascia |
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How are abduction and adduction of fingers defined?
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ab- away from middle finger
Add- toward middle finger so, middle finger can abduct in both directions and adducts to get back to it's normal spot |
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Palmaris Brevis
O I N A |
O = Med border of the Palmar Aponeurosis
I = Skin over the ulnar border of the hand N = Ulnar n. (C8, T1) A = Stabilize the palmar skin during gripping |
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Thenar Muscles
Thenar compartment: adductor compartment: |
Thenar compartment:
Abductor Pollicis Brevis Flexor Pollicis Brevis Opponens Pollicis adductor compartment: Adductor Pollicis |
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Abductor pollicis brevis
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O = Flexor Retinaculum; Trapezium; Scaphoid
I = Radial side and base of the proximal phalanx of the thumb*** N = Median n. (C8, T1) A = Abduct CMC 1 (thumb) Thumb ABDuction named so to be consistent with the plane of motion of finger abduction relative to the articulating joint surface Thumb is rotated 90 degrees as compared to the fingers (look at nails) Remember that APL inserts on 1st MC which is proximal to this |
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Flexor Pollicis Brevis
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O =
Lateral (Superficial) Head: Flexor Retinaculum; Trapezium Medial (Deep) Head: Capitate; Trapezoid I = Base of prox. phalanx of thumb Has a sesamoid bone N = Lateral Head: Median n. (C8, T1) Medial Head: Ulnar n. (C8, T1) A = Flex MCP 1; Aide opposition and adduction of the thumb Note: 2 heads with separate innervation What does this mean for testing hand movements to discriminate between median and ulnar nerve palsy? |
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Opponens Pollicis
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O = Flexor Retinaculum; Trapezium
I = 1st Metacarpal N = Median n. (C8, T1) A = Opposition of the thumb Involves flexion and rotation of thumb inward EVOLUTIONARY CONSIDERATIONS OF OPPOSITION: Likely related to bipedalism May have caused bipedalism or able to occur because of bipedalism With bipedalism hands were free for advanced manual use; likely resulted in use of tools |
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Adductor Pollicis
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O =
Oblique Head: Base of MC 2-4; Trapezoid; Trapezium; Capitate Transverse Head: 3rd MC I = Ulnar side and base of proximal phalanx of the thumb Has a sesamoid bone N = Ulnar n. (C8, T1) A = Adduction and Flexion of the thumb |
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Froment’s sign:
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Involvement of Ulnar nerve
thumb flexes as it tries to hold piece of paper (instead of just adducting) |
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Hypothenar muscles (hypothenar compartment)
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Abductor Digiti Minimi
Flexor Digiti Minimi Brevis Opponens Digiti Minimi |
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Abductor Digiti Minimi
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O = Pisiform
I = Proximal phalanx of 5th digit N = Ulnar n. (C8, T1) A = Abduction of MCP 5 |
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Flexor Digiti Minimi Brevis
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O = Hook of hamate; Flexor Retinaculum
I = Proximal phalanx of 5th digit N = Ulnar n. (C8, T1) A = Flex proximal phalanx of 5th digit |
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Opponens Digiti Minimi
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O = Hook of hamate; Flexor Retinaculum
I = Medial proximal ½ of 5th metacarpal Ulnar n. (C8, T1) A = Opposition of little finger Lies deep to other ABD and flexor muscles Draws 5th MC anteriorly and rotates towards palm of hand NOTE JUST LIKE OP IT ACTS AT MC SO MMT THAT WAY |
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Deep Muscles of the Hand (intrinsic compartment)
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Lumbricals
Palmar Interossei Dorsal Interossei |
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Lumbricals
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O = Radial side of FDP
I = Radial side of Extensor Hood N = #1 & 2: Median n. (C8, T1) #3 & 4: Ulnar n. (C8, T1) MCP flexion; IP extension Named for earthworm like appearance (species = Lumbricus) NOTE: DUAL INNERVATION |
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Palmar Interossei
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O = Palmar surface of MC 2, 4 & 5
I = Proximal phalanx; Extensor Hood of digits 2, 4 & 5 N = Ulnar n. (C8, T1) A = Adduct MCP Flex MCP; Extend IP |
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Dorsal Interossei
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O = Adjacent sides of two metacarpals (bipennate)
I = Proximal phalanx; Extensor Hood N = Ulnar n. (C8, T1) A = Abduct MCP Flex MCP; Extend IP “DAB”: Dorsal ABduct Can palpate 1st dorsal interossi by squeezing thumb against index finger |
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Summary of muscles of the hand
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Superficial Muscles:
Palmaris Brevis Thenar Muscles: Abductor Pollicis Brevis Flexor Pollicis Brevis Opponens Pollicis Adductor Pollicis Hypothenar Muscles: Abductor Digiti Minimi Flexor Digiti Minimi Brevis Opponens Digiti Minimi Deep Muscles: Lumbricals Palmar Interossei Dorsal Interossei |
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Synovial Sheaths
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Encase the long flexor and extensor tendons of the hand
Dorsal and Palmar Facilitates gliding of the tendons |
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Dorsal Tendon Sheaths 1-6
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I: Abd Poll Long / Ext Poll Brev
II: Ext Carpi Rad Long / Brev III:Ext Poll Long IV: Ext Dig / Ext Indicis V: Ext Dig Min VI: Ext Carpi Ulnaris |
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Anatomical Snuffbox
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Extensor Pollicis Brevis and Abductor Pollicis Longus
Sheath I Extensor Pollicis Longus Sheath III |
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Palmar Tendon Sheaths
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Common Sheath for the:
- Flexor Digitorum Superficialis - Flexor Digitorum Profundus Flexor Pollicis Longus Flexor Carpi Radialis |
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Intrinsic hand muscles NOT in a sheath
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Palmaris Longus
Flexor Carpi Ulnaris |
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Median nerve
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Median Nerve
Enters the hand via the Carpal Tunnel Carpal Tunnel Syndrome Innervates 2 and ½ thenar muscles: Opponens Pollicis Abductor Pollicis Brevis Superficial head of Flexor Pollicis Brevis Lumbricals 1 & 2 Sensation as above Shows that bulk of median nerve thru carpal tunnel but palmar branch goes outside of it Innervates center of palm so sometimes in carpal tunnel syndrome this area not producing sxs |
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Pressure in tunnel with carpal tunnel syndrome
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Carpal tunnel syndrome pts
32 mm Hg Normals 2 mm Hg Endoscopic technique to clear volume & decrease pressure in CT; clears undersurface of Transv Carpal Ligament EXPLAIN CARPAL TUNNEL |
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Median nerve palsy
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“Ape Hand”
Atrophy of the thenar muscles “Sign of Benediction” Limitation of thumb & MCP flexion at 2nd & 3rd digits Ape hand – movements limited to flex and extension movements of thumb (limited opposition and abduction) Benediction - Caused by inability to flex fingers 2 & 3 |
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ulnar nerve
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Ulnar Nerve
Outside the Carpal Tunnel Passes lateral to the Pisiform Motor Innervation: Majority of intrinsic muscles Both Dorsal and Palmar Interossi Lumbricals for digits 4 & 5 For thenar muscles: Adductor pollicis Deep head of flexor pollicis brevis Hypothenar Muscles Abductor Digiti Minimi Flexor Digiti Minimi Brevis Opponens Digiti Minimi |
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Ulnar Nerve Palsy
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“Claw Hand” or “Intrinsic Minus”
“Handlebar Palsy” Guyon Canal's syndrome Because innervates all of the interossi |
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Radial Nerve
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Radial Nerve
Cutaneous innervation to the hand ONLY Innervates the extensors of the wrist |
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Radial Nerve Palsy
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“Erb’s Palsy”, “Waiter Tip Palsy” or “Saturday Night Palsy”
Typically the injury is proximal to the wrist Often seen after traumatic births |
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BORDERS OF CARPAL TUNNEL:
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BORDERS OF CARPAL TUNNEL:
Anterior – flex retinac / Transv Carpal Lig Posterior – All carpal bones Lateral – scaphoid and trapezoid Medial – pisiform & hammate |
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CONTENTS OF CARPAL TUNNEL:
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BORDERS OF CARPAL TUNNEL:
Anterior – flex retinac / Transv Carpal Lig Posterior – All carpal bones Lateral – scaphoid and trapezoid Medial – pisiform & hammate CONTENTS OF CARPAL TUNNEL: Median Nerve 9 tendons 4 from FDS 4 from FDP Flex Pollicis Longus NOT ULNAR ARTERY OR NERVE !!! |
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Action of intrinsic muscles on DIPs and PIPs
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INTRINSICS ATTACH VOLAR/PALMAR AND DISTAL TO THE MCP SO WHEN THEY PULL THEY FLEX MCP (SEE RED ARROWS)
BUT ALSO ATTACH INTO LATERAL BANDS OF EXT DIG SO CAN EXTEND PIP |
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Where are arteries in relation to carpal tunnel?
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Note that arteries more superficial than carpal tunnel
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Extrinsic Finger Musculature
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Flexors:
Flexor Digitorum Superficialis Flexor Digitorum Profundus Extensors: Extensor Digitorum Extensor Indicis Extensor Digiti Minimi |
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Intrinsic Finger Musculature
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Lumbricals
Dorsal Interossei Palmar Interossei |
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Musculature of the thumb (intrinsic and extrinsic)
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Extrinsic Muscles:
Flexor Pollicis Longus Extensor Pollicis Brevis Extensor Pollicis Longus Abductor Pollicis Longus Intrinsic Muscles: Opponens Pollicis Abductor Pollicis Brevis Flexor Pollicis Brevis Adductor Pollicis |
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Joints of the Hand
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Radiocarpal Joint
Midcarpal Joint Carpometacaral Joints Metacarpalphalangeal Joints Interphalangeal Joints |
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Radiocarpal joint
components |
Bony Components:
Distal: Scaphoid Lunate Triquetrium Proximal: Radius Radioulnar Disc Loose, Strong Capsule Reinforced by Ligaments Same as those for the Midcarpal Joints |
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Radial inclination
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Slopes downwardly and toward ulnar and volar sides
Angled 23o ulnarly Angled 11o volarly allows greater ROM in those directions |
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Ulnar Variance
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Orientation of the Ulna relative to the Radius
Positive = Long ulna relative to the radius Potential impingement of the disc Negative = Short ulna relative to the radius Potential abnormal force distribution -> degeneration |
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Midcarpal joints
components |
Bony Components:
Proximal: Scaphoid Lunate Triquetrium Distal: Trapezium Trapezoid Capitate Hamate Mainly flexion and extension about some movement with ulnar and radial deviation The capsule is a continuation from the Radiocarpal joint. A large number of ligaments reinforce the strong loose capsule. Intrinsic Inter-carpal ligaments within the capsule Extrinsic Ligaments outside the capsule that span the ulna, radius and carpal bones |
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Midcarpal joint ligaments:
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Dorsal:
Radiocarpal - from radius across carpals Intercarpal - span across all carpals (2 ligs?) (Dorsal radiocarpal – from radial styloid process to lunate & triquetrum Appears as thickening in capsule) Palmar/volar: Radiocarpal -Radioscaphocapitate -Radiolunate -Radioscapholunate Radial Collateral Ulnar Collateral Scapholunate Lunotriquetral Palmar = volar These are intercapsular and named for prox & distal attachments Note all the names of attachment sites Radial & Ulnar collateral are capsular ligaments |
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Radial collateral ligament
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palmar midcarpal ligament
Radius to scaphoid, trapezium, and 1st MC bone Control radio-carpal movement in frontal plane |
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Palmar midcarpal ligaments - ulnar collateral ligament
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Ulna to pisiform and triq attachments
control carpal movement in frontal plane (during radial deviation) |
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Movement of the wrist: flexion/extension
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The majority of motion occurs either proximal or distal to the proximal row of carpal bones.
Flexion = Midcarpal > Radiocarpal (more motion between carpals) Extension = Radiocarpal > Midcarpal (more motion right at wrist) Convex carpals on concave radius & radioulnar disk |
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Movement of the wrist: flexion/extension
Between full flexion and neutral... |
Between Full Flexion and Neutral
Distal row glides on a fixed proximal row Same direction as that of the movement Movement at midcarpal joint |
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Movement of the wrist: flexion/extension
At neutral... |
At Neutral:
Distal row “locks” with the scaphoid bone Ligaments spanning capitate and scaphoid pull bones together into closed packed position So now during further movement these move together |
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Movement of the wrist: flexion/extension
Between Neutral and 45o of Extension: |
Between Neutral and 45o of Extension:
Distal carpal row, plus the Scaphoid moves on a fixed Lunate and Triquetrum |
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Movement of the wrist: flexion/extension
Between 45o of Extension to full extension: |
From 45o to Full Extension:
Scapholunate ligament tightens, “locking” both rows of carpal bones so they move as a single unit on the radius and radioulnar disc. Glide is opposite to the direction And then … EXTENSION TO FLEXION OCCURS IN REVERSE SEQUENCE |
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Summary of midcarpal joint movement during flexion and extension
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Full flex to neutral
- Distal row on fixed prox row Neutral to 45°extension -Distal row and scaphoid move on Lunate & Triquetrum 45°extension to full extension - Both rows of carpals move on radius and radioulnar disk |
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Movement at the Midcarpal Joint
(Radial Deviation) |
Distal row moves radially until it is “locked” with the proximal row
Carpals, as a unit, glide ulnarly on the radius and radioulnar disc Motion limited by: Ulnar Collateral ligament Scaphoid on the Radius |
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Movement at the Midcarpal Joint
(Ulnar Deviation) |
Distal row moves ulnarly until they are stopped by ligamentous tightness
The carpal bones, as a unit, slide radially on the radius and radioulnar disc. Checked by the radial collateral ligament. |
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Carpometacarpal joints
boney and ligamentous components, motion |
Boney components:
-Trapezoid, Capitate, Hamate -Metacarpals 2-5 Plane synovial joints -One degree of freedom -Flexion and Extension -2nd & 3rd metacarpals LEAST mobile -5th metacarpal the most mobile 40% of the hand’s total function is from these joints Basically more mobile from radial to ulnar side Ligamentous Support: Very strong proximal transverse metacarpal ligaments Weaker longitudinal carpometacarpal ligaments |
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Carpometacarpal joint of the thumb
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Bony Components:
-Trapezium -First Metacarpal Saddle Joint Three degrees of freedom -Flexion / Extension --Concave on Convex -Abduction / Adduction --Convex on Concave -Rotation Opposition - combo of abduction and flexion Ligamentous Support: Loose capsule Volar Trapeziometacarpal Ligament Dorsal Trapeziometacarpal Ligament Intermetarcarpal Ligament -Stabilizes the base of the thumb preventing excess motion |
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Metacarpalphalangeal Joints - MCP
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Bony Components:
Metacarpals 1-5 (convex) Proximal Phalanges (concave) Condyloid Joints Condyloid = oval surface fits into elliptical cavity Two degrees of freedom -Flexion / Extension --Greater ROM in medial MCP (ulnar) joints -Abduction / Adduction Arthrokinematic rotation about the Long Axis Ligamentous Support: Transverse Metacarpal Collateral Ligament Proper Accessory Collateral Volar Plate Transverse MC runs transversely Collaterals provide support in many directions but of course varus valgus VOLAR PLATE: Fibrocartilage that bends with capsule and provides reinforcement for it; limits hyperextension; enhances overall joint congruency Attaches b/w prox phallanx and MC head |
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Metacarpophalangeal joint of the thumb
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Same as the other MCP joints
Capsule is reinforced on the volar side by: Two sesamoid bones -Flexor Pollicis Brevis -Adductor Pollicis Intersesamoid ligament or Cruciate ligament |
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Interphalangeal Joints (IP)
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Bony Components:
Concave on convex at both PIP and DIP One degree of freedom -Flexion / Extension Increased ROM in fingers on ulnar side Ligamentous Support: Volar Plate Collateral ligaments |
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Palmar Arches
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Distal Transverse
Proximal Transverse Longitudinal Formed by the: Carpal Bones Transverse Carpal Ligament Flexor Retinaculum Palmar Intercarpal Ligaments Longitudinal runs vertically These help you cup objects |
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Prehension: power grip and precision grip
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Power:
Forceful flexion of all fingers used to clamp onto or hold objects Cylindrical Spherical Hook Precision grip: Used when grasping objects in order to manipulate them Pad-to-Pad Tip-to-Tip Pad-to-Side (lateral pinch) Lateral |
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Power Grips
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Cylindrical
Generally accompanied by ulnar deviation of MCP joints Spherical More interosseous activity is required Hook Generally doesn’t include the thumb |
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Precision Grips
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Pad-to-Pad (most common)
2 jaw chuck – thumb and index 3 jaw chuck – thumb, index, and middle (these possibly named for vice grips) Pad-to-Side (lateral pinch) Increased Adductor Pollicis activity Least precise of the precision grips Pad to side – b/w thumb and side of finger or knuckle Tip-to-Tip Requires interossei and full IP flexion Tip to tip – same muscle activity as pad to pad but need flexion too so can pick up something very fine. Lateral Prehension Palmar interossei are involved Lateral prehension is like holding a cigarette b/w two fingers |
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Finger Ligaments
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Prevent “bowstringing” and promotes proper tendon gliding
Annular Ligaments / pulleys (4 or 5) Cruciate Pulleys None in the thumb Flexor tendons pass thru fibro-osseous tunnels known as annular lig/pulleys (there are 4-5 of them) Cruciate pulleys in between them |
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Tendon sheaths in fingers
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Envelop the tendons in the hand
-Lined with synovial tissue -Augmented with the Ulnar and Radial bursae --Between the FDS and FDP -Held in place by the annular ligaments and cruciate pulleys Prevent friction of tendon against pulleys |
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Extensor Mechanism - active and passive components
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Passive Components (Ligaments and Connective Tissue):
Extensor Expansion (Dorsal Hood) Sagittal Bands Triangular Ligament Oblique Retinacular Ligament Active Components (Muscle): Extensor Digitorum Flexor Digitorum Superficialis Flexor Digitorum Profundus Dorsal and Palmar Interossei Lumbricals |
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Extensor Mechanism: Dorsal Hood
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Expansive ligamentous structure over and just distal to the MCP joint
Forms the basis for the rest of the components of the Extensor Mechanism Passive Active |
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Extensor Mechanism: Sagittal Bands
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Connects the volar surface of the hood to the volar plates and deep transverse metacarpal ligament
Stabilizes the volar plates and hood Helps centralize the ED tendon Prevent “bowstringing” of the ED |
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Extensor Mechanism - Triangular Ligament
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Connect the lateral bands of the ED
Also referred to as the Dorsal Retinacular ligament Some flexibility to allow movement |
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Extensor Mechanism: Oblique Retinacular Ligament
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Arise from sides of 1st phallanx and flexor tendon sheath
Insert into the lateral bands of the ED Helps control PIP and DIP movement More specifically arise from sides of A3 & A4 and from C1 |
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Extensor Mechanism: Extensor Digitorum
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Blends with the Dorsal Hood, just distal to the MCP joint
Some fibers insert deep under the hood into the proximal phalanx ED tendons associated with the hood split into 3 segments: Central band attaches to the base of the middle phalanx Lateral bands (2) cross the PIP, reunite and insert into the distal phalanx The EDC tendon splits into three slips JUST after it passes over each digit's MCP joint: the central slip and lateral bands. The central band inserts into the base of the middle phalanx, and the lateral bands continue distally and rejoin to insert onto the dorsal base of the distal phalanx. From Norkin & Levangie: “A central tendon crosses the PIP jt and and inserts onto the base of the middle phallanx. The two lateral bands pass to either side of the central tendon, cross the PIP jt, and reunite to insert in a single terminal tendon on the distal phallanx.” |
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Extensor Mechanism: Flexor Muscles
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Flexor Digitorum Profundus
Inserts into base of the distal phalanx Flexor Digitorum Superficialis Inserts at base of the middle phalanx Splits and reunites to accommodate the FDP |
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Extensor Mechanism: Dorsal and Palmar Interossei
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Insert into:
Proximal phalanx and Extensor Hood Lateral Bands and Central tendon of the ED Pass dorsal to the Transverse Metacarpal ligament and volar to the MCP joint axes |
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Extensor Mechanism: Lumbricals
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Arise from the FDP
Insert into the radial side of the Lateral Band Palmar/Volar to the Transverse Metacarpal Ligament and the MCP joint axis Greater moment arm for flexion vs Interossei, but smaller cross section |
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Describe diagram of extensor mechanism
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DORSAL HOOD (oblique green stripe)
SAGGITAL BANDS (vertical green stripe) TENDON SHEATH AND ANNULAR PULLEYS (dark red circles) ED TENDON (blue) Triangular ligament (small green striped triangle) OBLIQUE RETINACULAR LIGAMENT (Lime green line) FDS & FDP tendons (blue) INTRINSICS (Red: top – interossi; bottom lumbricals) |
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Function of the Extensor Mechanism
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Extensor Digitorum
Contraction of the ED pulls the hood over the MCP joint, causing extension of the PIP Lumbricals and Interossei They flex the MCP joint If they contract simultaneously with the ED, the MCP joint will extend Torque produced by ED exceeds all other muscles Extension of the PIP Joints: ED, Lumbricals and Interossei are all capable of extending the PIP joints by pulling on the hood Active contraction of the ED alone, however, is insufficient to extend the PIP joints “Intrinsic Minus” posture |
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Extension of the IP joints
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Extension of the IP Joints:
PIP and DIP extension are interdependent When PIP extends, DIP extends and vice versa As PIP is extended, ORL is stretched and pulls on the Lateral Bands, thus extending the DIP If intrinsics are paralyzed, the ED may extend the IP joints alone, but only if the MCP joint is passively maintained in flexion Maintains tension on the Extensor Hood “Bunnell’s” sign – clinical test for intrinsic paralysis As PIP is extended, ORL is stretched and pulls on the Lateral Bands, thus extending the DIP Because ORL inserts into the lateral bands of ED This is related to contraction of intrinsic muscles Bunnells sign – inability to extend IP jts unless MCP is passively maintained in flexion Extension of the DIP Joints: If the PIP is fully flexed by the FDS or passively, the DIP cannot be actively extended Central Tendon of the ED is stretched, which pulls the Extensor Hood distally Releases tension in the Lateral Bands and the ORL |
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Extension of the DIP Joints:
If the PIP is fully flexed by the FDS or passively, the DIP cannot be |
actively extended
Central Tendon of the ED is stretched, which pulls the Extensor Hood distally Releases tension in the Lateral Bands and the ORL |
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Extensor Mechanism Function: Coupled Actions of the IP joints
Flexion of the IP joints |
Flexion of the IP Joints:
Flexion of the DIP by the FDP will also cause flexion of the PIP - Interdependent Flexion at DIP: Stretches extensor tendon and pulls on ORLs Which exerts pull at proximal ORL attachment Lateral Bands allowed to move volarly Able to flex the DIP without flexion of the PIP, if the PIP is hyperextended or manually stabilized Dorsal restraining F’s are released; ED tendon stretched during DIP flexion – pulls ext hood distally – which allows relaxing of extensor expansion (hood) Lateral Bands allowed to move volarly (due to stretch of triangular ligament) so that PIP jt may flex Some individuals can hyperextend their PIP which then allows DIP flexion independently; This is because this position places the ORLs dorsally to the PIP joint axis; Then when the DIP flexes tension in the ORLs will result in PIP extension since they pass behind |
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So what to understand about coupled actions of the PIP and DIP?
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Active extension of PIP joint will be accompanied by extension of DIP joint
Active or passive flexion of the DIP joint will normally be accompanied by flexion of the PIP joint Full flexion of the PIP joint (actively or passively) will prevent active DIP extension |
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Finger injuries/deformities
"ulnar Drift" |
“Ulnar Drift”
Destruction and dislocation of the MP joints Typically seen in rheumatoid arthritis Anatomical Contributing Factors: (to ulnar drift) - normal mechanical advantage of the ulnar intrinsic muscles - asymmetry & ulnar slope of MC heads of index & middle fingers; - asymmetry of the collateral ligaments; - ulnar forces applied on pinch and grasp; - flexor tendons enter fibrous sheath at angle, exerting ulnar & palmar pull that is resisted in the normal hand; - carpal collapse can cause radial deviation of the carpi leading to compensatory MP joint ulnar deviation; - Pathology of Ulnar Drift: - w/ rheumatoid involvement of MP joint, there will be weakening & elongation of MP capsule & ligaments; - extensor tendon hoods are loosely fixed & vulnerable to disruption; - as resistance to displacing forces is lost, extensor tendons are displaced in an ulnar and palmar directions; - flexor tendons enter fibrous sheath at angle, exerting ulnar & palmar pull that is resisted in the normal hand; - as a result base of proximal phalanx moves ulnarly and palmarly; |
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Finger injuries/deformities
"Swan neck" deformity |
“Swan-Neck” Deformity
Tightness of the intrinsics leads to MP flexion Ligamentous laxity causes PIP hyperextension Tension in the FDP causes DIP flexion In RA or connective tissue disorders |
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Finger injuries/deformities
Boutonniere (“Buttonhole”) deformity |
Boutonniere (“Buttonhole”) deformity
PIP flexion with DIP hyperextension Avulsion of the central band of the ED This flexion deformity of the proximal interphalangeal joint is due to interruption of the central slip of the extensor tendon such that the lateral slips separate and the head of the proximal phalanx pops through the gap like a finger through a button hole (thus the name, from French boutonnière "button hole"). The distal joint is subsequently drawn into hyperextension because the two peripheral slips of the extensor tendon (still intact)are stretched by the head of the proximal phalanx(note that the two peripheral slips are inserted into the distal phalanx, while the proximal slip is inserted into the middle phalanx). This deformity makes it difficult or impossible to extend the proximal interphalangeal joint. |
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Finger injuries/deformities
"trigger finger" |
“Trigger” Finger
Thickening or nodule formation on the long finger flexor tendons Difficulty passing through the tendon sheath More common near the MP joint Frequently causes tenosynovitis Locking of the finger in flexion; snaps back out |
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Finger Injuries/deformities
Mallot (Mallet?) finger |
“Mallot” Finger
Disruption of the ED at the distal phalanx Flexion at DIP (inability to extend) |
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Finger injuries/deformities
finger sprain |
Finger Sprain
Disruption of the volar plate and collateral ligaments |
