Anatomy of the Hand 22-23(1) (1).pptx

Anatomy of the Hand Dr Catherine Hennessy [email protected] Learning Outcomes Describe the skeletal components of the writs and hand Describe the movements of the thumb and fingers Describe the tendons and muscles of the hand Describe the nerve and blood supply to the hand Skeletal Compo...

Anatomy of the Hand Dr Catherine Hennessy [email protected] Learning Outcomes Describe the skeletal components of the writs and hand Describe the movements of the thumb and fingers Describe the tendons and muscles of the hand Describe the nerve and blood supply to the hand Skeletal Component Anterior Posterior Carpals Metacarpals Phalanges Carpal Bones Lunate Scaphoid Triquetral/triquetrium Pisiform Trapezium Medial Hamate Trapezoid Carpal arch: Capitate d1 d5 Clinical: Fracture of scaphoid common (slow recovery - poor blood supply to proximal part: avascular Joints of the Hand Wrist (radiocarpal) Saddle joint Midcarpal/intercarpal Carpometacarpal Metacarpophalangeal Interphalangeal Wrist (Radiocarpal) Joint Between radius + disc and proximal row of carpal bones Reinforced by ligaments • Ulnar and radial collateral ligaments (limits abduction/adduction) • Ligaments on the palmar/dorsal surfaces (limits extension/flexion) Radial styloid process - Limits range of abduction Scaphoid Ulnar styloid process disc Triquetral Flexion/extension Abduction/adduction Circumduction Carpometacarpal Joints Plane joints - limited movement Except for the saddle joint (between trapezium and metacarpal of d1) - enables opposition Note: Thumb is at 90° to d2-5 Saddle joint Movements of the thumb: extension, flexion, abduction, adduction, opposition, reposition Metacarpophalangeal Joints Condylar joints: • Flexion/extension • Abduction/adduction Metacarpophalangeal joints Deep transverse metacarpal ligaments - Unifies metacarpals - Not between digit 1 and 2 Interphalangeal Joints Hinge joints: • Flexion/extension Proximal interphalangeal joints (PIPs) Distal interphalangeal joints (DIPs) Palmar Aponeurosis Thickened deep fascia Triangular shape Continuous with palmaris longus Longitudinal fibres Transverse fibres Clinical: Dupuytren’s contracture Long Flexor Tendons to Digits From muscles in anterior forearm Pass through carpal tunnel Flexor digitorum superficialis (d2-5) Flexor retinaculum (transverse carpal ligament) - Prevents bowing of tendons Flexor digitorum profundus (d2-5) Median nerve Flexor pollicis longus (d1) Note: synovial sheaths surrounding tendons Long Flexor Tendons to Digits Synovial sheaths Flexor pollicis longus Flexor retinaculum (cut) Flexor digitorum profundus Flexor digitorum superficialis Tendons enter fibrous digital sheaths Flexor Tendon Insertions Alternating fibrous annular and cruciate ligaments. Annular ligaments Fibrous digital sheath are also known as pulleys Synovial sheath PIP DIP Flexor digitorum profundus Flexor digitorum superficialis To base of distal phalanx To base of middle phalanx Long Extensor Tendon to Digits From muscles in posterior forearm Extensor retinaculum Extensor digitorum Extensor indicis d2-5 Extensor digit minimi Extensor pollicis longus Extensor pollicis brevis d1 Abductor pollicis longus Extensor hoods / Dorsal digital expansion (triangular aponeurosis) Extensor Digitorum Insertion Extensor digitorum Extensor hood (dorsal digital expansion) Extensor hoods for attachment for intrinsic muscles Extensor Hoods Extensor hood Lumbrical muscle Interosseous muscle Lumbricals and interossei insert into the extensor hoods Anatomical Snuff Box Abductor pollicis longus To base of 1st metacarpal Lateral/anterior border Extensor pollicis brevis To base of proximal phalanx Scaphoid Floor Radial artery Trapezium Medial/ posterior border Extensor pollicis longus To base of distal phalanx Clinical: Radial pulse + palpate scaphoid Lumbricals Link flexor to extensor tendons Ulnar nerve Lumbricals Origin Flexor Digitorum Profundus tendons Insertion Extensor Hoods Action Flexion of MCP jts Extension of IP jts Nerve Supply Median nerve (lateral two tendons) Ulnar nerve (medial two tendons) Median nerve d2 Lateral to d2-5 Lumbrical Precision grip (hold pen / d3 d4 d5 Palmar Interossei • Interossei sit between the metacarpals • 3 Palmar Interossei • No palmar interossei for D1 (performed by adductor pollicis muscle) or D3 Palmar Interossei Origin Metacarpals Insertion Extensor Hoods (d2, d4, d5) Action Adduction of the MCP jts Nerve Supply Ulnar nerve Palmar interossei Relative to middle finger (D3) d2 d4 d5 Dorsal Interossei Interossei sit between the metacarpals 4 Dorsal interossei No dorsal interossei for D1 or D5 (performed by thenar and hypothenar muscles) Dorsal Interossei Origin Metacarpals Insertion Extensor Hoods (d2, d3, d4) Action Abduction of the MCP jts Nerve Supply Ulnar nerve Dorsal interossei d4 Relative to middle d3 d2 Thenar and Hypothenar Muscles Flexor retinaculum Thenar muscles Fine movements of the thumb (d1) Hypothenar muscles Fine movements of the little finger (d5) Origin of muscles: flexor retinaculum and adjacent carpal bones Thenar and Hypothenar Muscles Abductor Pollicis Brevis Flexor Pollicis Brevis (Opponens Pollicis lies deep) Abductor Digiti Minimi Flexor Digiti Minimi (Opponens Digiti Minimi lies deep) Opponens Pollicis Opponens Digiti Minimi https://3d4medic.al/51WdxENu Thenar Muscles Abductor Pollicis Brevis Flexor Pollicis Brevis Origin Scaphoid, Trapezium & Flexor Retinaculum Origin Trapezium & Flexor Retinaculum Insertion Proximal phalanx of thumb Insertion Proximal phalanx of thumb Action Abduction of the thumb Action Flexion of the thumb Nerve muscles:Supply Median nerve Three 1. Abductor pollicis brevis Origin 2. Flexor pollicis brevis Insertion Action 3. Opponens pollicis (deepest) Nerve Supply Nerve Median nerve Supply Opponens Pollicis Trapezium & Flexor Retinaculum 1st metacarpal Opposition of the thumb Median nerve Hypothenar Muscles Abductor Digiti Minimi Flexor Digiti Minimi Origin Pisiform, Hamate & Flexor Retinaculum Origin Hamate & Flexor Retinaculum Insertion Proximal phalanx of 5th digit Insertion Proximal phalanx of 5th digit Action Abduction of the 5th digit Action Flexion of the 5th digit Nerve Ulnar nerve Supply Digiti Minimi Opponens Ulnar nerve Three muscles:Nerve Supply Origin 1. Abductor Digiti Minimi 2. Flexor Digiti Minimi Insertion Action 3. Opponens Digiti Minimi (deepest) Nerve Supply Hamate & Flexor Retinaculum 5th metacarpal Opposition of the 5th digit Ulnar nerve Adduction of the Thumb Deep to thenar muscles Adductor Pollicis Origin Oblique head: Base of 2nd and 3rd metacarpals and capitate Transverse head: shaft of 3rd metacarpal Insertion Base of proximal phalanx Action Adduction of the first MCP jt Nerve Supply Ulnar nerve Oblique head Transverse head Blood Supply Radial artery Ulnar artery Towards dorsal surface Form complex anastomosis in hand (So that blood can reach all structures in any hand position) Deep Palmar Arch Below long flexor tendons Deep palmar arch Floor of anatomical snuff box Radial artery First dorsal interosseous muscle Superficial Palmar Arch Above long flexor tendons Ulnar artery Superficial palmar arch Common palmar digital arteries Proper palmar digital arteries Median Nerve Median nerve Passes through Carpal tunnel Recurrent branch (to the thenar muscles) !! Palmar branch is spared in carpal tunnel syndrome = No loss of sensation on the palm of the hand Digital nerves supplying Lateral 2 lumbricals Sensory d1 to ½ d4 Clinical: Carpal tunnel syndrome Ulnar Nerve Ulnar nerve Deep branch Hypothenar muscles Interossei Medial 2 lumbricals Adductor pollicis Superficial branch Sensory ½ d4 and d5 Clinical: Damage to the Ulnar nerve = Clawed hand due to lumbricals of d4 & d5 not working resulting in MCP joint extension & IP joint flexion. Ulnar Paradox = clawed hand is worse if ulnar nerve damaged at wrist due to FDP being spared meaning IP joints can also flex. If FDP wasn’t working (damage at elbow) IP joints would be extended.