Hand Therapy Review Course Washington University St. Louis, MO April 7 9, 2017 Over eighty percent of activities of daily living involve grasping or seizing objects with the hand. (Katz et al., 1970) Anatomy and Kinesiology of the Hand David Levy, MS, OTR/L, CHT How your brain sees your hand Objectives We will be able to identify and understand the relationships between the following structures in the hand: The hand occupies nearly 1/3 of motor cortex Surface anatomy Bones Joints Muscles Tendons Nerves Arteries Surface anatomy Volar Surface anatomy Dorsal Surface anatomy Creases Arches Muscle groups Tendons Joints
Arches balance between mobility and stability Surface Anatomy Proximal transverse arch distal carpal row; capitate is keystone; fixed Distal transverse arch Metacarpal heads; keystone 2 nd /3 rd MCs; mobile Longitudinal arch 2 nd & 3 rd MCs; flattens and deepens Bony anatomy Bones Metacarpals Latin/Greek origin; meta = beyond carpo = wrist Phalanges Latin/Greek any body of troops in close array. a number of individuals, especially persons united for a common purpose. Anatomy, Zoology: any of the bones of the fingers or toes. How many bones are in your hand? 19 bones distal to the carpus 5 Metacarpals 14 Phalanges Fingers: 3 each Thumb: 2 Joints Joints 4 types CMC all 5 digits MPJ all 5 digits PIJ fingers DIJ fingers IPJ thumb
CMC Joints Thumb kinematics Thumb Saddle Joint 2 df Flex/Ext (ll to palm) Abd/Add ( to palm) Opposition = net effect Fingers Plane joints (1 df) Flexion/Extension glide Stability more than mobility Neumann, 2002 Thumb kinematics: abduction Thumb kinematics: flexion, extension Palmar/Volar Ligament of the 1 st CMC Strong but loose fibrous capsule Superficial ligaments Primary stabilizer Palmar beak ligament Helps prevent dorsal subluxation of metacarpal base Muscles crossing the joint also add to stability. Extrinsic and Intrinsic Tendon Forces Cooney, et al. 1977 Joint compression forces averaged 12 kg at the CMC joint during simple pinch with 1 kg of applied force Compression forces of as much as 120 kg may occur at the CMC joint during strong grasp
CMC Joints: function Saddle joints are responsible for positioning thumb and small finger for opposition or prehension. CMC peripheral joints (1,4,5) are much more mobile than 2,3 2 nd & 3 rd CMC are fixed joints Increased stability of the 2 nd /3 rd CMC acts as a fixed point for the other CMC joints to move around, allowing cupping of the hand Brand MP Joints Condyloid Joints: 2 degrees of freedom Flexion/extension and abduction/adduction Flexion increases as you move ulnarly IF to SF Normal range = (+45)0/90 110 degrees Collateral ligaments are loose in extension, taut in flexion Should be immobilized in flexion, with collateral ligaments on stretch Test for ligament injury with MPJ in flexion MP Joint anatomy MP Joint motion Extension / Flexion Abduction / Adduction IP Joints PIP Joint Anatomy PIP most important for hand function Similar structure of PIP and DIP joints Stability through PCL, ACL, volar plate and joint capsule.
PIP Joint Anatomy Collateral ligaments limit deviation Volar plate limits hyperextension Critical Corner = point where PCL, ACL and VP converge. Important in joint stability Dynamic stability increased by muscles, tendons and ligaments crossing joint: central slip, lateral bands, transverse and oblique retinacular ligaments Enhances joint stability With flexion, proximal portion buckles/folds like accordion IP joints should be immobilized in extension to prevent shortening of volar plate through check reign ligaments (unless volar plate has been disrupted) Volar Plate PIP Collateral ligaments Collateral ligaments critical in providing stability with pinch Protected Position of the Hand MPs 70 Flexion Maintain Length of Collaterals IPs 0 Extension Prevent Volar Plate contracture Wrist 0 Avoid Increased CT Pressure Open 1 st Web Space Location Innervation Function Zones Compartments Muscles Extrinsic Muscles Flexors: FDS, FDP, FPL median nerve except FDP to ring and small fingers (ulnar) Extensors: APL, EPB, EPL, EIP, EDC, EDM radial nerve
Extrinsic digital flexors FDP, FDS, FPL Extrinsic extensors Superficial view Flexor digitorum profundus (FDP) Deep view Flexor digitorum superficialis (FDS) FPL Extrinsic extensors Intrinsic Muscles All For One And One For All (lateral to medial) Thenar: APB, FPB, OP median nerve, except deep head FPB (ulnar) AdPol Hypothenar: ODM, FDM, ADM ulnar nerve Pad and Dab Lumbricals, Palmar (3) and Dorsal Interossei (4) ulnar nerve except 2 nd /3 rd lumbricals (median) Thumb Muscles Abductor Pollicis Brevis Flexor Pollicis Brevis Opponens Pollicis Adductor Pollicis Hypothenar Muscles Abductor Digiti Minimi Flexor Digiti Minimi Opponens Digiti Minimi Intrinsic Muscles Intrinsics of the Thumb Thenar Muscles Abductor Pollicis Brevis Flexor Pollicis Brevis Opponens Pollicis Involved in placement and stabilization for prehension Adductor Pollicis responsible for power/strength OP deep to FBP and ABP
Lumbricals Interossei Lumbricals Originate from FDP tendons and insert into lateral bands Origin MC shafts Actions Flex MPs, extend IPs Ab/Ad fingers Lumbricals and Interossei together Intrinsic minus hand: ulnar nerve out Intrinsic Plus Position: All intrinsics working together
Intrinsic minus hand function Opponens Anti Claw Orthosis Extrinsic flexor tendons Flexor Tendons FDP, FDS, FPL Zones Sheaths Pulleys Vinculae Locations FDP flexes finger PIP and DIP. Independent slip to IF. AIN innervation to IF and LF; ulnar n to RF and SF. FDS flexes PIP. Median nerve FPL flexes thumb IP. AIN Flexor Tendons in Carpal Tunnel Flexor Tendon Zones Zone 1: distal to FDS insertion Zone 2: A1 pulley to FDS insertion Zone 3: distal end of CT to A1 Zone 4: CT Zone 5: Proximal Retrieved from: http://scghed.com/2013/12/cme-121213-hand-injuries/
Zone 2 Flexor sheaths and bursa Synovial sheath provides nutrition to tendon and low friction gliding No Man s Land Tendon Sheath Flexor Tendon Pulley System Maintains tendons and sheath close to bone to prevent bow stringing and enhance mechanical advantage A1 Pulley is site of Trigger Finger pathology Flexor Tendon Pulley System Flexor Tendon Pulley System A2 and A4 most biomechanically important Loss will result in decreased flexion and grip strength If ruptured, will need orthosis to prevent bowstringing
Flexor Tendon Pulley System A1 pulley is site of trigger finger More prevalent in women and diabetics Synovial linings decrease friction in tight places (CT and FDS bifurcation) Function is dependent on intact gliding structures; sheaths and pulley system can enhance or impede gliding Tendon gliding Extrinsic blood supply to flexor tendons Diffusion plays a greater role in tendon nutrition than perfusion Vincula Length Tension Issues FDS and FDP are dependent on wrist position to enhance function; 35 40 ext for maximum grip ECRB provides counterbalance to prevent wrist flexion; ECRL contributes with power grip Extrinsic Flexors: FDS and FDP Wrist Position matters: Tenodesis Extrinsic extensors EPB, APL, EPL, EI, EDC, EDM Compartments Zones Juncturae Extensor mechanism
Extensor tendons smaller and flatter than flexors Extensor compartments 1st Dorsal Compartment: Site of DeQuervain s Injured more often than flexors * Superficial view of extensors Extensor Tendon Zones Odds and Evens : odd numbered zones are at joints Extensor tendons do not have a pulley system All extensor tendons are extrasynovial except for zone 7 Retrieved from: http://scghed.com/2013/12/cme-121213- hand-injuries/ Extensor Zone injuries Zone 1 mallet; resisted flexion Zone 3 central slip; laceration or crush Zone 4 high bone tendon interface; scar adhesions resulting in PIJ ext lag Zone 5 MPJ/EDC; fight bite Juncturae Tendinae Branch off of RF EDC, linking it to the LF and SF EDC (sometimes index). Never to EIP Assists adjacent digits in extension; can mask injury to an EDC Helps maintain dorsal placement of extensors tendons over MPs during flexion Wartenburg s
EIP and EDM add independent function not strength EDC can produce IP extension if MPs blocked in slight flexion Extrinsic Extensors EDC flattens into extensor hood just distal to MCP joint Central tendon inserts onto base of middle phalanx Lateral bands arise at PIP joint and reunite into terminal tendon Extensor Mechanism Sagittal bands Extensor Mechanism Lateral bands Sagital band dorsal expansion (hood) Central slip Extensor digitorum tendon ORL arises from the A2 pulley near proximal phalanx ORL lies volar to PIP joint and dorsal to DIP joint Intrinsics contribute to the lateral bands Extensor Mechanism Lateral bands Sagital band dorsal expansion (hood) Central slip Extensor Mechanism Extensor digitorum tendon Oblique Retinacular Ligaments (ORL) Synchronous IP flexion or extension; links IPJs
Nerves 3 peripheral nerves to hand Median Ulnar Radial Motor innervations Sensory innervations Lesion signs and symptoms Nerves Median Ulnar Radial Volar Dorsal Median Nerve Innervation FDS Lumbricals (IF & MF) APB OP FPB (superficial head) Anterior Interosseous FDP (IF & MF) FPL Median nerve Which muscle would you MMT for CTS? Why? Median Nerve Signs and symptoms of median nerve lesion observable in hand Compromised FDS to any digits; FPL; median intrinsics Parasthesias through median sensory distribution Dorsal and Palmar interossei Lumbricals (RF & SF) Adductor Pollicis Flexor Pollicis Brevis (deep head) Hypothenar: Abductor Digiti Minimi Flexor Digiti Minimi Opponens Digiti Minimi Flexor Digitorum Profundus (Ring & Small fingers) Ulnar Nerve Innervation
Ulnar Nerve Guyon s Canal: boundaries are pisoform (medial) and hook of hamate (lateral). Contains nerve and artery. ~4 cm long Pathology sources: arthritic changes ganglia hook of hamate fx s Guyon s Canal: Cyclists Palsy Ulnar Nerve Ulnar nerve Which muscle would you MMT for high ulnar nerve lesion (e.g. CuTS?) Why? Ulnar Nerve Signs and symptoms of lesion at hand level Intrinsic weakness Parasthesia in sensory distribution Low level lesion? At what level would you suspect injury if dorsal ulnar hand parasthesia is present? Froment s Sign FPL substitutes for weak AdP Indicates ulnar nerve lesion Supinator Extensor Carpi Radialis Longus Extensor Carpi Radialis Brevis Posterior Interosseous Extensor Digitorum Communis Extensor Pollicis Longus Extensor Pollicis Brevis Abductor Pollicis Longus Extensor Indicis Proprius Extensor Digiti Minimi Extensor Carpi Ulnaris Radial Nerve Innervations
Radial nerve lesion Arteries Signs and symptoms observable in hand Inability to extend MPJs Parasthesia along dorsal radial sensory (DSRN) distributions aka Wartenburgs Syndrome Functional Hand Patterns Prehension Grasp and Pinch Hand Strength & Function Power Grip Stability and large forces without need for precision Cylindrical or spherical Precision grip Hand Strength & Function Key Pinch (power pinch) Hand Strength & Function
Hand Strength & Function Hand Strength & Function Precision pinch Fine control to objects between the thumb and IF without need for power Hook grip Components of Grip & Pinch Strength Extrinsic & intrinsic Sensation ROM Tendon gliding Lymphatic function Motor control Motor plan, timing, recruitment, coordination Stable base, esp. wrist & thumb Load Transfer Quality of bone & articular cartilage Vascularity & skin integrity Conclusion Use caution when studying hand anatomy and kinematics. Much of what s in hand orginates elsewhere. Remember: hand bone is connected to arm bone. Why Hand Therapy Exists Questions?
Hand Therapists References matter Cooper, C. (2014). Fundamentals of hand therapy: Clinical reasoning and treatment guidelines for common diagnoses of the upper extremity (2 nd ed.). St. Louis: Elsevier Mosby. Drake, R. L., Vogl, W., Mitchell, A. W., & Gray, H. (2005). Gray's anatomy for students. Philadelphia: Elsevier/Churchill Livingstone. Houglum, P. A., & Bertoti, D. (2012). Brunnstrom's clinical kinesiology (6th ed.). Philadelphia: F.A. Davis. General anatomy and musculoskeletal system. (2007). Thieme Atlas of Anatomy Image Collection. New York: Thieme Medical Publishers. Neumann D., (2010) Kinesiology of the Musculoskeletal System. St Louis: Elsevier Mosby. Skriven, T. M., Osterman, A. L., Fedorczyk, J. M., Amadio, P. C. (2011). Rehabilitation of the hand and upper extremity (6 th ed.). Philadelphia: Elsevier Mosby.