The Wrist and the Hand - Arthrology PDF

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THE WRIST AND HAND JOINTS

THE WRIST JOINT • RADIOCARPAL JOINT • MIDCARPAL JOINT

THE JOINTS OF THE HAND 1. INTERCARPAL JOINTS 2. TRAPEZIO-METACARPAL JOINT 3. CARPO-METACARPAL JOINT 4. INTERMETACARPAL JOINT 5. METACARPO-PHALANGEAL JOINT 6. INTERPHALANGEAL JOINT

THE WRIST JOINT THE RADIO-CARPAL JOINT ARTICULAR SURFACES

SYNOVIAL, BIAXIAL, ELLIPSOID JOINT PROXIMALLY, ARTICULAR DISC AND RADIUS  WHICH FORMS A COMPOUND CONCAVE SURFACE WHICH ARTICULATES WITH DISTALLY, TRIQUETRUM, LUNATE  AND SCAPHOID WHICH FORMS A COMPOUND CONVEX SURFACE.

A SYNOVIAL MEMBRANE LINES THE ARTICULAR CAPSULE AND IS SEPARATE FROM BOTH THE INFERIOR RADIO-ULNAR JOINT AND THE INTERCARPAL JOINTS. A SMALL MENISCUS EXISTS BETWEEN THE ULNA STYLOID PROCESS AND THE TRIQUETRUM, TOGETHER WITH A SMALL PRESTYLOID SYNOVIAL RECESS. THE MENISCUS MAY OSSIFY.

LIGAMENTS 1. PALMAR RADIOCARPAL LIGAMENT BROAD AND MEMBRANOUS. IT RUNS FROM THE ANTERIOR INFERIOR MARGIN OF THE RADIUS. THE FIBRES RUN INFERO-MEDIALLY TO THE ANTERIOR SURFACES OF THE PROXIMAL CARPAL ROW EXCLUDING  THE PISIFORM. IT BLENDS WITH THE JOINT CAPSULE. 2. PALMAR ULNOCARPAL LIGAMENT IT IS A ROUNDED LIGAMENT RUNNING FROM THE ANTERIOR ASPECT OF THE BASE OF THE ULNAR STYLOID PROCESS AND THE ARTICULAR DISC TO THE ANTERIOR ASPECT OF THE LUNATE AND TRIQUETRUM. 3. DORSAL RADIOCARPAL LIGAMENT IT IS THINNER AND WEAKER THAN THE CORRESPONDING ANTERIOR LIGAMENT. IT EXTENDS FROM THE POSTERIOR BORDER OF THE RADIUS RUNNING INFERO-MEDIALLY TO THE DORSAL ASPECT OF THE PROXIMAL ROW OF THE CARPALS, EXCLUDING THE PISIFORM, IT BLENDS WITH THE DORSAL MARGIN OF THE ARTICULAR DISC OF THE INFERIOR RADIO-ULNAR JOINT. 4. RADIAL COLLATERAL LIGAMENT

RUNS FROM THE TIP OF THE STYLOID PROCESS TO THE LATERAL ASPECT OF THE SCAPHOID AND CONTINUES TO THE TRAPEZIUM. IT IS NOT A WELL DEVELOPED LIGAMENT. 5. ULNAR COLLATERAL LIGAMENT RUNS FROM THE TIP OF THE STYLOID PROCESS AND DIVIDES INTO TWO: 1. TO THE MEDIAL ASPECT OF THE TRIQUETRUM, 2. TO THE PISIFORM BONE.

MOVEMENT OF THE JOINT MOST OF FLEXION AT THIS JOINT COMPLEX OCCURS AT THE MID-CARPAL JOINT. MOST OF EXTENSION AT THIS JOINT COMPLEX OCCURS AT THE RADIO-CARPAL (WRIST) JOINT. NERVE SUPPLY ANTERIORLY THE JOINT IS SUPPLIED BY THE ANTERIOR  INTEROSSEOUS NERVE, A BRANCH OF THE MEDIAN NERVE, TOGETHER WITH THE DEEP BRANCH OF THE ULNAR NERVE. POSTERIORLY THE JOINT IS SUPPLIED BY THE POSTERIOR  INTEROSSEOUS NERVE, A BRANCH OF THE RADIAL NERVE, TOGETHER WITH THE DORSAL BRANCH OF THE ULNAR NERVE.

MIDCARPAL JOINT

IT IS A SYNOVIAL, UNIAXIAL HINGE JOINT.

WHEN THE "HAND" IS FLEXED, MOST OF THE FLEXION MOVEMENT OCCURS AT THIS JOINT. ARTICULAR SURFACES

PROXIMAL AND DISTAL CARPAL ROWS

MOVEMENT

ROUGHLY S-SHAPED WHICH TENDS TO PREVENT ABDUCTION AND ADDUCTION OF THE JOINT. THE JOINT DOES ALLOW FLEXION AND EXTENSION AND MOST OF FLEXION OF THE "HAND" OCCURS HERE. MOST OF EXTENSION OF HE "HAND" OCCURS AT THE RADIO-CARPAL (WRIST) JOINT.

ARTICULAR CAPSULE AND SYNOVIAL CAVITY THIS IS CONTINUOUS THROUGHOUT THE CARPUS FROM THE CENTRAL MID-CARPAL LINE. PROJECTIONS EXTEND PROXIMALLY AND DISTALLY BETWEEN ADJACENT CARPAL BONES. SEPARATE JOINT CAVITIES EXIST FOR: I) PISO-TRIQUETRAL II) TRAPEZIUM - FIRST METACARPAL JOINTS. LIGAMENTS AND

RADIAL AND ULNAR COLLATERAL LIGAMENTS

THE CARPAL LIGAMENTS PROVIDE STABILITY FOR THE MIDCARPAL JOINT. BIND THE CARPAL BONES AS INDIVIDUALS AND AS GROUPS. 1. INTEROSSEOUS LIGAMENTS OCCUR BETWEEN ADJACENT BONES IN THE PROXIMAL AND DISTAL ROWS. 2. DORSAL AND PALMAR LIGAMENTS OCCUR AS SHORT IRREGULAR BUNDLES BETWEEN THE ROWS, THE LARGEST BEING THE RADIATE CARPAL LIGAMENT WHICH RADIATES FROM THE HEAD OF THE CAPITATE BONE ON THE PALMAR SURFACE. 3. COLLATERAL LIGAMENTS OCCUR AS:I) LATERAL LIGAMENT WHICH IS THE STRONGEST AND MOST DISTINCT, AND CONNECTS THE SCAPHOID WITH THE TRAPEZIUM. II) MEDIAL  LIGAMENT WHICH CONNECTS THE TRIQUETRUM WITH THE HAMATE. NERVE SUPPLY ANTERIORLY BY THE ANTERIOR INTEROSSEOUS BRANCH OF THE MEDIAN NERVE TOGETHER WITH THE DEEP BRANCH OF THE ULNAR NERVE. POSTERIORLY BY THE POSTERIOR INTEROSSEOUS BRANCH OF THE RADIAL NERVE TOGETHER WITH THE DORSAL BRANCH OF THE ULNAR NERVE.

INTERCARPAL JOINTS

SYNOVIAL, MULTIAXIAL PLANE JOINTS

THESE ARE ALL SMALL JOINTS BETWEEN ADJACENT CARPAL BONES USUALLY SHARING A COMMON SYNOVIAL SPACE AND FLUID WITH THE MIDCARPAL JOINT. THEY ARE DIVIDED INTO PROXIMAL AND DISTAL ROW JOINTS. THE PISO-TRIQUETRAL JOINT HAS AN INDIVIDUAL JOINT SPACE HOWEVER. LIGAMENTS ★ MOVEMENTS ARE SEVERELY RESTRICTED BY PALMAR AND DORSAL INTERCARPAL LIGAMENTS. PROXIMAL ROW 1.DORSAL AND PALMAR INTEROSSEOUS LIGAMENTS THE PALMAR LIGAMENTS ARE THE WEAKEST AND THINNEST AND RUN TRANSVERSELY. 2.PISOHAMATE AND PISOMETACARPAL LIGAMENTS ARE EXTENSIONS OF THE FLEXOR CARPI ULNARIS TENDON.

3.INTEROSSEOUS LIGAMENTS OCCUR BETWEEN EACH ADJACENT BONE. DISTAL ROW 1.DORSAL AND PALMAR INTEROSSEOUS LIGAMENTS RUN TRANSVERSELY. 2.INTEROSSEOUS LIGAMENTS OCCUR BETWEEN EACH ADJACENT BONE AND ARE THICKER THAN THE PROXIMAL SET. NERVE SUPPLY IS THE SAME AS THE MIDCARPAL JOINT.

CARPO-METACARPAL JOINTS THERE ARE THREE JOINT/JOINT TYPES ENCOMPASSED IN THIS CLASS:1. THE TRAPEZIO-METACARPAL JOINT AT THE BASE OF THE THUMB. 2. THE JOINTS OF THE SECOND, THIRD, FOURTH AND FIFTH METACARPALS WITH THE CARPALS. 3. THE INTERMETACARPAL JOINTS BETWEEN THE SECOND, THIRD, FOURTH AND FIFTH METACARPALS. 1. THE TRAPEZIO-METACARPAL JOINT MULTIAXIAL SADDLE JOINT ALLOWING GREATEST MOVEMENT OF ALL THE CARPO-METACARPAL JOINTS. IT OCCURS BETWEEN THE TRAPEZIUM AND BASE OF THE FIRST METACARPAL FORMING A SINGLE, SELF-CONTAINED JOINT SPACE. BOTH JOINT SURFACES ARE SLIGHTLY CONCAVO-CONVEX GIVING MATCHING, RECIPROCATING SADDLE SHAPES. THE ORIENTATION OF THE JOINT AND THE AXIS OF THE FIRST METACARPAL IS ROTATED, SO THAT THE PLANE OF JOINT MOVEMENT IS ACROSS THE FACE OF THE PALM IN FLEXION AND EXTENSION AND AT RIGHT ANGLES TO THE REMAINDER OF THE METACARPALS FLEXION AND EXTENSION. JOINT CAPSULE SURROUNDS THE JOINT AND IS THICK BUT LOOSE ALLOWING RELATIVELY FREE MOVEMENT. IT RUNS AROUND THE BASE OF THE FIRST METACARPAL TO THE ARTICULAR MARGIN OF THE TRAPEZIUM AND IS THICKEST DORSALLY AND LATERALLY. THE SYNOVIAL MEMBRANE LINES THE CAPSULE AND DOES NOT COMMUNICATE WITH THE OTHER CARPO-METACARPAL JOINTS.

ACCESSORY LIGAMENTS REINFORCE THE CAPSULE ANTERIORLY, POSTERIORLY AND LATERALLY. JOINT SURFACES THE SHAPE OF THE JOINT SURFACES ALLOW ACTIVE MOVEMENT IN ALL PLANES FLEXION, EXTENSION, ABDUCTION, ADDUCTION, ROTATION AND CIRCUMDUCTION. THE ORIENTATION OF THE TRAPEZIUM ROTATES THE PLANES OF MOVEMENT THROUGH 90 DEGREES AND FLEXION OF THE JOINT IS ALWAYS CONCURRENT WITH MEDIAL ROTATION TO GIVE OPPOSITION. NERVE SUPPLY 1. PALMAR SURFACE IS BY THE ANTERIOR INTEROSSEOUS NERVE, A BRANCH OF THE MEDIAL N. 2. DORSAL SURFACE IS BY THE POSTERIOR INTEROSSEOUS NERVE, A BRANCH OF THE RADIAL N.

2. SECOND, THIRD, FOURTH AND FIFTH METACARPO-CARPAL JOINTS EACH OF THESE JOINTS IS CLASSIFIED AS A SYNOVIAL PLANE JOINT ALTHOUGH THE ACTUAL SURFACES ARE FAR FROM PLANE. EACH OF THE JOINTS POSSESSES AN ARTICULAR CAPSULE WHICH IS REINFORCED BY PALMAR AND DORSAL INTEROSSEOUS LIGAMENTS. THE DORSAL SET ARE THICKEST AND STRONGEST. EACH METACARPAL BONE RECEIVES SHORT INTEROSSEOUS LIGAMENTS FROM ADJACENT CARPAL BONES. BOTH THE PALMAR AND DORSAL SETS HAVE SIMILAR ARRANGEMENTS, BUT THE PALMAR SET ARE THINNER AND LESS DISTINCT. SYNOVIAL MEMBRANE LINES THE COMMON CAPSULE AND IS OFTEN CONTINUOUS WITH THE INTERCARPAL SYNOVIAL MEMBRANE. AN ANATOMICAL VARIATION INVOLVING THE FIFTH AND FOURTH METACARPAL SPACES WITH THE HAMATE MAY OCCUR WHICH MAY BE SEPARATE FROM THE MAIN SYNOVIAL SPACE. NERVE SUPPLY 1. PALMAR SURFACE OF SECOND, THIRD, AND LATERAL HALF OF THE FOURTH JOINT IS BY THE ANTERIOR INTEROSSEOUS NERVE, A BRANCH OF THE MEDIAN NERVE.

2. PALMAR SURFACE OF MEDIAL HALF OF THE FOURTH AND THE FIFTH JOINT IS BY THE DEEP BRANCH OF THE ULNAR NERVE. 3. DORSAL SURFACE OF SECOND, THIRD AND HALF OF THE FOURTH JOINT IS BY THE POSTERIOR INTEROSSEOUS NERVE, A BRANCH OF THE RADIAL NERVE. 8 IPD 1999 17 4. DORSAL SURFACE OF HALF OF THE FOURTH AND THE FIFTH JOINT IS BY THE DORSAL BRANCH OF THE ULNAR NERVE. 3. INTERMETACARPAL JOINTS ARE SMALL SYNOVIAL PLANE JOINTS WHICH OCCUR BETWEEN THE ADJACENT BASES OF THE SECOND, THIRD, FOURTH AND FIFTH METACARPAL BONES. THESE JOINTS SHARE THEIR JOINT SPACE AND SYNOVIAL FLUID WITH THE CARPO-METACARPAL JOINTS AND THE JOINT CAPSULE AND SYNOVIAL MEMBRANES ARE CONTIGUOUS. ALL MOVEMENTS ARE SEVERELY LIMITED BY STRONG TRANSVERSE LIGAMENTS WHICH OCCUR ON BOTH DORSAL AND PALMAR SURFACES PASSING FROM THE BASE OF ONE METACARPAL TO THE ADJACENT BONE. NERVE SUPPLY IS THE SAME AS FOR THE METACARPO-CARPAL JOINTS. NOTE: THERE IS A THIN AND RELATIVELY LONG TRANSVERSE LIGAMENT BETWEEN THE FIRST AND SECOND METACARPAL BONE. THIS LIGAMENT DOES NOT RESTRICT THE MOVEMENT OF THE FIRST METACARPAL (OF THE THUMB) IN THE SAME WAY AS THE SECOND, THIRD, FOURTH AND FIFTH ARE RESTRICTED. METACARPO-PHALANGEAL JOINTS ARE SYNOVIAL, BIAXIAL (CONDYLOID-KNUCKLE) JOINTS ALLOWING FLEXION / EXTENSION AND ABDUCTION / ADDUCTION. JOINT SURFACES ARE COVERED BY ARTICULAR HYALINE CARTILAGE. THE ARTICULAR HEAD OF THE METACARPAL IS BICONVEX AND EXTENDS ONTO THE PALMAR SURFACE. IT IS LONGER THAN IT IS BROAD GIVING IT A RECTANGULAR SHAPE CURVED THROUGH 90 DEGREES. THE ARTICULAR SURFACE ALSO EXTENDS COLLATERALLY. THE ARTICULAR BASE OF THE PHALANX IS BICONCAVE, HAS A SUBSTANTIALLY SMALLER SURFACE AREA THAN THE CORRESPONDING METACARPAL SURFACE AND IS BROADER THAN IT IS LONG I.E. THE TRANSVERSE DIMENSION IS GREATER THAN THE ANTERO-POSTERIOR DIMENSION. THE JOINT CAPSULE IS ATTACHED AROUND THE MARGIN OF THE ARTICULAR SURFACES ON BOTH THE METACARPAL AND PHALANGEAL BONES WITH A REDUNDANT FOLD ON THE DORSAL SURFACE OF THE JOINT AND SMALL LOOSE EXTENSIONS

COLLATERALLY. THE CAPSULE IS LINED BY SYNOVIUM AND IS STRONGLY REINFORCED BY LIGAMENTS COLLATERALLY AND ON THE PALMAR SURFACE. THE CAPSULE IS REINFORCED ON THE PALMAR SURFACE BY PALMAR PLATES. LIGAMENTS ARE DIVIDED INTO THREE TYPES:1. PALMAR PLATE OR LIGAMENTS ARE THICK, FIBROCARTILAGINOUS PLATES ON THE PALMAR SURFACE OF THE JOINTS BETWEEN THE COLLATERAL LIGAMENTS. THE PLATES ARE VERY FIRMLY ATTACHED TO THE PALMAR SURFACE OF THE BASE (PROXIMAL END) OF THE PHALANX AND TO THE COLLATERAL LIGAMENTS. IT IS LOOSELY ATTACHED, BY LIGAMENT TO THE METACARPAL. THE PALMAR SURFACE OF THE PLATE BLENDS WITH THE DEEP TRANSVERSE LIGAMENTS AND IS GROOVED BY THE FLEXOR TENDON. THE DEEP SURFACE OF THE PLATE IS SMOOTH AND "ARTICULAR" AND IS IN CONTACT WITH THE METACARPAL HEAD. 2. COLLATERAL LIGAMENTS ARE EACH COMPOSED OF TWO PARTS:I) A ROUND, STRONG CORD II) A FLAT, THINNER FAN I) THE CORD IS ATTACHED TO THE POSTERIOR TUBERCLE OF THE METACARPAL HEAD AND THE ADJACENT DEPRESSION. IT RUNS ANTERIORLY AND DISTALLY TO ATTACH TO THE ANTERO-LATERAL MARGIN OF THE BASE OF THE PHALANX AS FAR AS THE ATTACHMENT OF THE PALMAR PLATE. II) THE FAN HAS A SIMILAR ATTACHMENT TO THE CORD ON THE METACARPAL HEAD AND RUNS, FANNING AS IT DOES, TO ATTACH TO THE LATERAL MARGIN OF THE PALMAR PLATE. 3. DEEP TRANSVERSE LIGAMENTS ARE COMPOSED OF THREE SHORT WIDE BANDS BETWEEN THE SECOND AND THIRD, THIRD AND FOURTH, FOURTH AND FIFTH METACARPALS. THEY ATTACH INTO THE COLLATERAL ASPECTS OF THE PALMAR PLATES AND TO THE DORSAL DIGITAL EXPANSION. THEY LIMIT EXCESSIVE ABDUCTION OF THE JOINTS. FUNCTIONS THE PALMAR PLATE PROTECTS THE JOINTS= PALMAR SURFACE, PARTICULARLY WHEN THE HAND GRIPS TIGHTLY IN A FIST. THE GROOVE ON THE PALMAR PLATE HELPS TO GUIDE THE FLEXOR TENDONS. THE COLLATERAL LIGAMENTS STABILISE THE PALMAR PLATE AND ALSO PREVENT EXCESS COLLATERAL MOVEMENT. THE POSITION OF THE COLLATERAL LIGAMENTS RESULTS IN TIGHTENING OF THE LIGAMENT DURING JOINT FLEXION MAKING THE JOINT MORE SECURE AS FLEXION INCREASES. THE DEEP TRANSVERSE LIGAMENTS PREVENT SEPARATION OF THE DIGITS AND STABILISE THE HAND AND FIST DURING ALL MOVEMENTS.

SESAMOID BONES OCCUR AT THE FIRST AND VARIABLY AT SECOND AND FIFTH JOINTS. THE DORSAL ASPECT OF THE JOINT POSSESSES A THINNER CAPSULE WHICH IS SEPARATED FROM THE EXTENSOR TENDON BY A BURSA. NERVE SUPPLY IS SIMILAR TO THE METACARPO-CARPAL JOINTS.

INTERPHALANGEAL JOINT SYNOVIAL, UNIAXIAL, HINGE JOINTS ALL ARTICULAR SURFACES ARE COVERED WITH HYALINE ARTICULAR CARTILAGE. THE PHALANGEAL HEAD (DISTAL) IS BICONVEX WITH A MIDLINE GROOVE RUNNING ANTERO-POSTERIORLY. THE ARTICULAR SURFACE EXTENDS TO THE ANTERIOR (PALMER) SURFACE SIMILAR TO THE METACARPO-PHALANGEAL JOINT. THE PHALANGEAL BASES (PROXIMAL) OF THE SECOND, THIRD, FOURTH AND FIFTH DIGITS ARE ALL BICONCAVE. IN THE THUMB (POLLUX) ONLY TWO PHALANGEAL BONES OCCUR. THE ARTICULAR SURFACES ARE BICONCAVE WITH A MID-LINE CREST WHICH GIVES THE ARTICULAR SURFACE A BROAD SHALLOW M SHAPE. HYALINE CARTILAGE COVERS THE SURFACE WHICH IS SUBSTANTIALLY SMALLER IN SURFACE AREA THAN THE PHALANGEAL HEAD PROXIMALLY. RECIPROCAL ARTICULAR SURFACES OF THE INTERPHALANGEAL JOINT JOINT CAPSULE ATTACHES TO THE ARTICULAR MARGINS AND A SMALL REDUNDANT FOLD OCCURS DORSALLY. THE DORSAL PORTION IS ALSO THE THINNEST PART OF THE CAPSULE BUT IS REINFORCED BY THE EXTENSOR TENDONS. ANTERIORLY THE JOINT CAPSULE POSSESSES A PALMAR PLATE WHICH IS EXACTLY SIMILAR TO THOSE OF THE MCP JOINTS, BUT SMALLER. THE PALMAR PLATES DO NOT OF COURSE POSSESS TRANSVERSE LIGAMENTS. LIGAMENTS ALL CLASSIC HINGE JOINTS POSSESS COLLATERAL LIGAMENTS AND THE INTERPHALANGEAL JOINT IS NO EXCEPTION. THESE LIGAMENTS HAVE SIMILAR ATTACHMENTS TO THOSE IN THE MCP JOINTS SO THAT THE PROXIMAL ATTACHMENT IS DISPLACED DORSALLY. WHEN FLEXION OF THE JOINT OCCURS THE COLLATERAL LIGAMENTS TIGHTEN SECURING THE JOINT. THE LIGAMENTS, TOGETHER WITH THE SHAPE OF THE JOINT SURFACE, MAKE ANYTHING BUT PURE FLEXION/EXTENSION IMPOSSIBLE. NERVE SUPPLY THE SAME AS THE METACARPO-CARPAL JOINTS.

MUSCLES OF THE HAND are grouping in:

MUSCLES OF THENAR EMINENCE: 1. ABDUCTOR POLLICIS BREVIS 2. FLEXOR POLLICIS BREVIS 3. OPPONENS POLLICIS 4. ADDUCTOR POLLICIS MUSCLES OF HYPOTHENAR EMINENCE: 1.ABDUCTOR DIGITI MINIMI 2.FLEXOR DIGITI MINIMI. 3.OPPONENS DIGITI MINIMI. 4. PALMARIS BREVIS INTRINSIC MUSCLES: 1. 8 INTEROSSEI [4 DORSAL & 4 PALMAR] 2. 4 LUMBRICALES...