Quiz #3 - Hand & Wrist

Flexor Digitorum Profundus (FDP)

Flexes fingers in slow action. MAIN FINGER FLEXOR. INNERVATION: Median nerve. Reinforced by FDS when speed and flexion against resistance are required. Extending wrist increases operating distance - contraction more efficient in producing strong grip.

Extrinsic Finger Muscles & Extensor Expansion

Long extensor tendons end at extensor expansion.

Longitudinal Arch

Longitudinal concavity formed by carpals, metacarpals, and phalanges. Very mobile when flex/extend. Row of metacarpal heads in the highest point on arch. Arch is longest at metacarpal 2. Shortest at metacarpal 5 due to different lengths of metacarpals. Segments contributing to arch allow 280 degrees of combined motion. -- ~70-90 degrees depending on what MP joint looking. -- Up to 110 degrees in small finger.

Intrinsic Finger Muscles & Extensor Expansion

Lumbricals and interossei meet with central slips of long tendon to form lateral bands. Lumbricals insert into radial border of extensor expansion on dorsum of respective digits.

Tendons of Flexor Digitorum Superficialis

Palpated as digits are alternately flexed and extended.

Flexor Carpi Ulnaris Tendon (FCU)

Palpated as it crosses anterior aspect of wrist near medial side and inserts into pisiform. Guide to ulnar nerve and artery.

Extensor Mechanism

Made up of lateral bands and a terminal tendon which inserts on the base of the distal phalanx. * Primary function: extend IP joints.

Ulnar Nerve - Motor and Sensory Innervation

SENSORY: supplies skin on medial side of palm. - Supplies medial half of dorsum of hand, 5th finger, medial half of 4th finger. - Superficial Branch: supplies cutaneous branches to anterior surfaces of medial one and a half fingers. MOTOR: known as nerve of fine movements - innervates muscles concerned with intricate hand movements. - Deep Branch: supplies hypothenar muscles, medial two lumbricals (4th and 5th), AD, deep head of FPB, and all interossei.

Extensors of MP Joints

- Extensor digitorum. - Extensor indicis. - Extensor digiti minimi.

Flexors of DIP Joints

- Flexor digitorum profundus.

Extensors of Thumb

Extensor pollicis brevis (MP) Extensor pollicis longus (IP)

Wrist Creases

Proximal, middle, and distal. * Distal wrist crease: indicates proximal border of flexor retinaculum.

Hypothenar Compartment

Abductor Digiti Minimi. Flexor Digiti Minimi Brevius. Opponens Digiti Minimi.

Anastomosis of Hand

Deep palmar and superficial palmar arches anastomosis. Two blood supplies in hand. Allow for blood flow if there was a problem in one.

Extension of Thumb

Extensor pollicis longus, extensor pollicis brevis, abductor pollicis longus. RADIAL NERVE. Anatomical position - thumb out to side. All three joints (CMC, MP, IP) FRONTAL PLANE.

Thenar Muscles

Form thenar eminence on lateral surface of palm. ** Responsible for opposition of thumb. Abduction: APL & APB. Adduction: adductor pollicis and 1st dorsal interossei. Extension: EPL, EPB, APL. Flexion: FPL, FPB. Opposition: opponens pollicis. --- Occurs at CMC joint of thumb.

Lateral Bands

Formed on each side of the PIP joint. Lumbricals/interossei meet with slips of long tendon to form these. Diverge and rejoin at base of distal phalanx to form terminal tendon.

Dorsal Interosseous Muscles

Four, located between metacarpals. Abducts fingers (DAB) & assists lumbricals in MP flexion and IP extension. Bipennate. INNERVATION: Ulnar nerve.

Interphalangeal Joints (IP)

HINGE - 1 DOF. - Flex/Extend. --- 1st digit: Frontal. ---Digit 2-5: Sagittal. 1st Digit: IP joint only. Digits 2-5: PIP and DIP.

Radial Artery

Lies on floor of anatomical snuff box. Enters palm by passing between heads of 1st dorsal interosseous muscle. Turns medially and passes between heads of AD. Ends by anastomosing with deep branch of ulnar artery to form deep palmar arch.

Floor of Snuff Box

Scaphoid and (less directly) trapezium are palpable in floor of snuff box.

Central Compartment

Short muscles of hand. Lumbricals and long flexor tendons.

Palmar Interosseous Muscles

Three, on palmar surface of digits 2, 4, 5 metacarpals. Adducts fingers (PAD) and assists lumbricals in MP flexion and IP extension. INNERVATION: Ulnar nerve.

Median Nerve - Route and Compression

Under FDS, palmar branch breaks off superficial to flexor retinaculum. Through carpal tunnel. Palmar digital branches to fingers. COMPRESSION: in carpal tunnel. Carpal Tunnel Syndrome: swelling, repetitive flexing motions of tendons, vibration, cold. --- Median nerve isn't a fan, needs rest.

Radial and Ulnar Collateral Ligaments

Very complicated. Provide passive control to wrist motion in frontal plane. Ulnar taut in radial deviation - radial taut in ulnar deviation. Radial: radial styloid to scaphoid. Ulnar: ulnar styloid to triquetrum.

Carpometacarpal Joint (Thumb)

Digit 1 - Thumb. SADDLE - 2 DOF. - Flex/Extend (frontal). - Abduct/Adduct (sagittal). Opposition: combination of flex/abduct. Reposition: combination of extend/adduct.

Carpometacarpal Joints (CMC)

Digits 2-5. PLANE - 3 DOF. Digit 2 & 3: Immobile. Digit 4: slight flex/extend. Digit 5: flex/extend.

Deep Palmar Arch

Direct continuation of radial artery. Formed mainly by radial artery. Lies across metacarpals just distal to their bases. Gives rise to three palmar metacarpal arteries and princeps pollicis artery.

Abductors of Digits

Dorsal interossei. Abductor digiti minimi.

Interosseous Compartments

Interossei in separate compartments between metacarpals.

Opposition of Thumb

Opponens Pollicis.

Opposition of Pinky Finger

Opponens digiti minimi.

Central Slip

AKA. Central Tendon. Portion of long extensor tendon continues distally to insert at base of middle phalanx. EXTENDS PIP JOINT.

Thenar Compartment

Abductor Pollicis Brevius. Flexor Pollicis Brevius. Opponens Pollicis.

Abduction of Thumb

Abductor pollicis longus and brevis. RADIAL AND MEDIAN NERVE. AP to start, thumb coming anteriorly. CMC joint only. SAGITTAL PLANE.

Carpal Tunnel Syndrome

Carpals are floor and flexor retinaculum is roof. 9 structures pass through the CT: FDS and FDP tendons and median nerve. Repetitive flexion movements lead to this. Swelling, repetitive motions of tendons, vibration, and cold. Median nerve can get compressed and needs to be rested. *** Any lesion that reduces size of carpal tunnel or increases size of structures that pass through it. -- Unable to opposite thumb. -- To relieve compression and resulting symptoms, partial or complete surgical division of flexor retinaculum (carpal tunnel release) may be needed.

Bones of the Wrist

Distal radius and ulna. Radial & Ulnar styloid. ** Radial is larger. Carpals: SLTPTTCH. - Scaphoid, Lunate, Triquetrum, Pisiform. - Trapezium, Trapezoid, Capitate, Hamate.

Hypothenar Muscles

INNERVATION: Ulnar Nerve. Produce hypothenar eminence on medial side of palm.

Terminal Tendon

If you tear this can heal quickly in splint (mallet injury). - Ex. Basketball jamming DIP. EXTENDS DIP Joint.

Opposition/Reposition of Thumb

Opponens Pollicis. Opposition: Begins with thumb in extended position, initially involves abduction and medial rotation of 1st metacarpal (cupping palm) produced by action of opponens pollicis and then flexion at MP joint. Reposition: opposite. Returning to AP.

Adductors of Digits

Palmar interossei.

Flexion Creases

Palmar skin presents several more or less constant flexion creases where skin is firmly bound to deep fascia.

Tendon of FCR and Palmaris Longus

Palpated anterior to wrist. Little lateral to middle of wrist and usually observed by flexing closed fist against resistance. Tendon of PL serves as guide to median nerve - lies deep to it.

Palmar Creases

Radial longitudinal crease ("life line"), proximal, and distal transverse palmar creases.

Abductors of Thumb

Abductor pollicis longus. Abductor pollicis brevis.

Knuckles

Head of metacarpals.

Bones of the Hand

Metacarpals: - Form bones of palm of hand between carpals and phalanges. Phalanges: - Digits have 3: proximal, middle, distal. - Thumb has 2: proximal and distal.

Radial Nerve - Motor and Sensory Innervations

SENSORY: superficial branch. - Deep fascia near dorsum of wrist. - Supply skin and fascia over lateral two thirds of dorsum of hand, dorsum of thumb, and proximal parts of lateral one and a half digits.

Flexors of MP Joints

- Lumbricals. - Dorsal interossei. - Palmar interossei.

Cruciate Ligaments of Digits

3 - like a cross.

Tendons of Abductor Pollicis Longus and Extensor Pollicis Brevis

Indicate lateral (anterior) boundary of anatomical snuff box.

Flexors of PIP Joints

- Flexor digitorum profundus. - Flexor digitorum superficialis.

Extensors of DIP/PIP Joints

- Lumbricals. - Dorsal interossei. - Palmar interossei.

Dorsal Aponeurosis

Tape holding tunnels down. 6 osseous tunnels.

Annular Ligaments of Digits

5 - more rectangular. AKA. Fibrous digital sheath. 2 & 4 over proximal phalanx shaft, middle phalanx shaft are needed for full digital flexion.

Adduction of Thumb

Adductor Pollicis and 1st Dorsal Interosseous. ULNAR NERVE. Thumb coming back from abduction - back against first finger. CMC joint only. SAGITTAL PLANE.

Adductor Compartment

Adductor Pollicis.

Adductors of Thumb

Adductor pollicis.

Extensor Expansion

Aka. Dorsal Hood. Where extensor digitorum tendons stop! * Primary function: extend IP joints. Distal end of metacarpals and along phalanges. - Four tendons of ED flatten to form these. Hood of extensor expansion over head of metacarpal is anchored on each side to palmar ligament. Each extension digitorum tendon divides into median band (passes to base of middle phalanx) and two lateral bands (pass to base of distal phalanx).

Intercarpal Joints

Articulations between individual bones in proximal and distal rows of carpal bones. PLANE - 3 DOF. - Capable of slight, gliding movements in 3 planes.

Synovial Cyst

Aka. Ganglion Cyst. Most commonly on dorsal side of wrist - but can also be volar. Grape to plum size. Mucinous fluid (called ganglion). Can produce pain and paresthesia (numbness/tingling) of sensory distribution of median nerve. Nontender cystic swellin. Thin walled cyst. Close to and communicates with synovial sheaths. Very common at distal attachment of extensor carpi radialis brevis tendon. Can enlarge with flexion of wrist and produce compression on median nerve by narrowing carpal tunnel.

Ulnar Bursa

Bathes FDS and FDP - Digits 2-5. Goes all the way up digit 5. --- Digits 2-4 have own individual bursae. Can get tendonitis (swelling in bursa) - can get stuck.

Collateral Ligaments of MP and IP Joints

Connects each MP, PIP, and DIP joint laterally and medially. Prevents medial and lateral motion at IP joints. MP joints: taut/stretched when in full flexion (closed-pack). IP joints: taut/stretched when in full extension.

Volar Plate (Ligament)

Connects each MP, PIP, and DIP joint volarly. Prevents hyperextension of these joints. Blends with joint capsule. Provide stability - preventing posterior dislocation of proximal phalanx.

Deep Transverse Metacarpal Ligament

Connects metacarpal heads 2-5 volarly. Connected to volar plates at MP joints. Goes OVER volar plates on MP joint.

Annual & Cruciate Ligaments

Cruciate: x over joint. Annular: pulleys - on shaft of phalanx. Hold tendons to bone (FDS and FDP).

Radial Nerve - Route and Compression

Deep branch: goes through supinator and to extensor compartment muscles. Superficial branch: emerges at lateral wrist and branches to dorsal digital nerves. NO radial nerve intrinsic hand muscles!! --- Just skin.

Metacarpalphalangeal Joint

Digits 2-5. CONDYLOID - 2 DOF. - Flex/Extend (sagittal). - Abduct/Adduct (frontal). Hyaline cartilage over distal metacarpals articulating with proximal phalanx. Convex head of metacarpals and concave base of proximal phalanx.

Superficial Palmar Arch - Ulnar Artery

Direct continuation of ulnar artery. Gives rise to three common palmar digital arteries. -- Anastomose with palmar metacarpal arteries from deep palmar arch.

Transverse Arch

Distal transverse arch. Transverse concavity formed by heads of metacarpals 2-5. More mobile. Decreased when fingers extend. Increased when fingers flex as metacarpals 4 and 5 are mobile. Metacarpals 2&3 provide stable base of hand/axis of other metacarpals. Metacarpals 4&5 flex/extend to conform to objects for tight grasp and bring fingertips toward thumb for manipulation. Metacarpal 1 is very mobile to conform to many size objects in various planes of movement.

Ulnar Nerve - Route and Compression

Emerges at pisiform and enters Guyon's canal. Deep in hand. Palmar and dorsal digital branches to fingers. COMPRESSION: can get impinged at guyon's canal and cubital tunnel. - Guyon's Canal Syndrome (aka. Ulnar tunnel syndrome): much LESS common. - Cubital Tunnel Syndrome: pressure/stretching of ulnar nerve. --- Cause numbness/tingling of pinky and ring fingers, weakness in hand, or pain in forearm.

Ulnar Artery

Enters hand anterior to flexor retinaculum between pisiform and hook of hamate. Through Guyon's canal (ulnar canal). Lies lateral to Ulnar Nerve.

Extensors of Wrist

Extensor Carpi Radialis Longus. Extensor Carpi Radialis Brevis. Extensor Carpi Ulnaris.

Flexor Apparatus (FDP/FDS)

FDS splits to allow FDP to pass through and continue to DIP. - FDS attaches to middle phalanx, flexes MP and PIP. - FDP attaches to distal phalanx- flexes MP, PIP, and DIP.

Flexors of Thumb

Flexor pollicis brevis (MP) Flexor pollicis longus (IP)

Tendon of Extensor Pollicis Longus

Indicates medial (posterior) boundary of snuff box.

Synergistic Activity of Extrinsic and Intrinsic Hand Muscles

Muscles of hand and wrist work synergistically during prehension. Wrist extensors stabilize wrist in neutral to direct extrinsic flexor tendon pull to the fingers. --- Work with extrinsic flexors (FDS and FDP) to put them into a position where they don't become actively insufficient. Ulnar deviators can work with thumb muscles to create more stable position. --- Putting more in line with forearm. --- Without, can have active insufficiency. Without synergistic activity, active insufficiency can interfere. --- If wrist is in flexion, extrinsic finger flexors can't flex fingers to grasp. --- Wrist extensors stabilize wrist into neutral.

Extensor/Supinators of Forearm

Posterior compartment. INNERVATION: Radial Nerve. Extensor tendons held in place in wrist region by extensor retinaculum - prevents bowstringing of tendons when hand is extended at wrist joint.

Transverse Digital Flexion Creases

Proximal digital crease located at root of digit, approximately 2 cm distal to MP joint. Proximal digit crease of thumb crosses obliquely, proximal to 1st MP joint. Middle digit crease: lies over PIP joint. Distal digit crease: lies proximal to DIP joint.

Carpal Arch

Proximal transverse arch. Transverse concavity formed by the distal carpal bones. Slightly moveable. Maintained whether fingers are flexed/extended due to immobile nature of distal carpals.

Tendon Sheath

Reduce friction for extensor tendons as they traverse osseofibrous tunnels formed by attachment of extensor retinaculum to distal radius/ulna. Protected by this as they run under the retinaculum - reduce friction. All digits have their own respective digital sheaths.

Synovial Tendon Sheaths

Reduce friction for extensor tendons as they traverse osseofibrous tunnels formed by attachment of extensor retinaculum to distal radius/ulnar.

Median Nerve - Motor and Sensory Innervation

SENSORY: sends fibers to skin on lateral palmar surface, sides of first three digits, lateral half of 4th digit, and dorsum of distal halves of digits. MOTOR: In forearm, mainly innervates flexors and pronators. - 1.5 exceptions innervated by ulnar nerve. - Supplies 2.5 thenar muscles. --- APB, FPB, Opponens pollicis. - Supplies 1st and 2nd lumbricals. - Issues grabbing things with hand, etc. Injury has more impact on sensation since it supplies thumb, index, middle, some of ring, and radial palm.

Tendons of Extensor Digitorum

Seen on dorsum of hand when wrist is extended against resistance and digits abducted. Flatten to form extensor expansions (dorsal hood) of fingers.

Lumbricals

Short muscles of the hand. Originate on FDP tendons. Inserts into radial border of extensor expansion on dorsum of respective digits. Extends digits 2-5. Flexes MP joints. Four slender muscles - worm like appearance. INNERVATION: --- 1st and 2nd: Median Nerve. --- 3rd and 4th: Ulnar Nerve.

Palmaris Brevis

Small muscle in subcutaneous tissue of hypothenar eminence. NOT IN HYPOTHENAR COMPARTMENT. Deepens hollow of palm, aiding in palmar grip. Covers/protects ulnar nerve and artery. Attached proximally to medial border of palmar aponeurosis and to skin on medial border of hand.

Retinaculum

Organized into 6 dorsal compartments. Tendons are wrapped down by the retinaculum (on extensor retinaculum - aka. dorsal aponeurosis). -- Held snug against dorsum of hand. Flexor Retinaculum: 9 tendons go through here - along with median nerve.

Radial Pulse

Where radial artery lies on anterior surface of distal end of radius - lateral to FCR tendon. Artery felt pulsating between tendons of FCR and APL - where it can be compressed against the radius.

Transverse Carpal Ligament

Aka. Flexor Retinaculum. Volarly attaches pisiform and hamate to scaphoid and trapezium. Connects between radial and ulnar wrist. Holds palm of hand in cupped position. Over flexor retinaculum. 9 tendons go through here along with the median nerve, where we get carpal tunnel syndrome. Base of carpal tunnel is proximal and distal row of carpal bones. Prevents bowstringing and protects median nerve. Forms roof of carpal tunnel.

Flexor/Pronators of Forearm

Anterior compartment. INNERVATION: Median nerve. 1.5 exceptions are innervated by Ulnar nerve. Tendons of most flexor muscles pass across anterior surface of wrist and held in place by palmar carpal ligament and flexor retinaculum (aka. transverse carpal ligament). Deep muscles don't cross elbow. Long Flexors of Digits: FDS and FDP (flex MP and wrist joints).

Dupuytren's Contracture

Disease of palmar fascia resulting in progressive shortening, thickening, and fibrosis of palmar fascia and palmar aponeurosis. Pulls 4th and 5th digits into partial flexion at MP and PIP joints. Frequently bilateral. Treatment: surgical excision of fibrotic pars of palmar fascia to free fingers.

Midcarpal Joint

Distal surface of proximal row of carpals articulates with proximal surface of distal row of carpals. CONDYLOID - 2 DOF. - Flex/extend. - Radial/ulnar deviation. ** More extension & radial deviation here! Complex direction of movement.

Radiocarpal Joint

Distal surface of radius and articular disc at distal ulna articulates with proximal row of carpals. CONDYLOID. - 2 DOF. - Flex/extend. - Radial/ulnar deviation. Convex on concave. Pisiform in proximal row but doesn't participate in joint.

Movements of Fingers

Flex, extend (sagittal). Abduct, adduct (frontal). Lumbricals: flex MP joints & extend IP joints. -- In front of axis on MP joint and behind axis at IP joints. -- Interossei assist with this as well. Hand Intrinsics: divided into four compartments. -- Thenar, adductor, hypothenar, and central.

Motions of the Wrist

Flexion/extension - sagittal plane - coronal/frontal axis. Ulnar/Radial Deviation/Abduction/Adduction: frontal plane - sagittal axis. * In deviations: proximal row of carpals go opposite way and distal row goes same way.

Abductors of Wrist (Radial Deviation)

Flexor Carpi Radialis. Extensor Carpi Radialis Longus.

Flexors of Wrist

Flexor Carpi Radialis. Flexor Carpi Ulnaris. Palmaris Longus.

Adductors of Wrist (Ulnar Deviation)

Flexor Carpi Ulnaris. Extensor Carpi Ulnaris.

Flexion of Thumb

Flexor Pollicis Longus and Brevis. MEDIAN NERVE. Thumb rubbing over calluses on palm - never losing contact of palm. All three joints (CMC, MP, IP). FRONTAL PLANE.