Extensor retinaculum & dorsal digital expansion Dr.N.Mugunthan
This document discusses the extensor retinaculum of the hand and the dorsal digital expansion. It describes the extensor retinaculum's attachments, its division into 6 compartments through which various tendons pass. It also explains how the dorsal digital expansion forms a hood over each metacarpal head and trifurcates into bands at the proximal phalanx, with contributions from surrounding tendons.
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Extensor retinaculum & dorsal digital expansion Dr.N.Mugunthan
- 1. EXTENSOR RETINACULUM & DORSALDIGITAL EXPANSION Lecture by Dr.N.Mugunthan.MBBS,MS,DNB,MNAMS,PhD. Professor of Anatomy SMIMS
- 2. Learning objectives Extensor retinaculum •Attachments • 6 compartments • Structures passing deep to it Dorsal digital expansion • Formation © Dr.N.Mugunthan
- 3. Extensor retinaculum ofhand © Dr.N.Mugunthan
- 4. Back of forearm Superficialgroup: • *Brachioradialis • *Anconeus • *Extensor carpi radialis longus • Extensor carpi radialis brevis • Extensor digitorum • Extensor digiti minimi • Extensor carpi ulnaris Deep group: • Supinator • Abductor pollicis longus • Extensor pollicis longus • Extensor pollicis brevis • Extensor indicis © Dr.N.Mugunthan
- 5. Back of forearmcont… Superficial group: • *Brachioradialis • *Anconeus • *Extensor carpi radialis longus • Extensor carpi radialis brevis • Extensor digitorum • Extensor digiti minimi • Extensor carpi ulnaris Deep group: • Supinator • Abductor pollicis longus • Extensor pollicis longus • Extensor pollicis brevis • Extensor indicis © Dr.N.Mugunthan
- 6. Extensor retinaculum Attachment: • Medialend: styloid process of ulna, triquetral and pisiform • Lateral end: lower part of anterior border of radius © Dr.N.Mugunthan
- 7. Extensor retinaculum cont… Fromlateral to medial: following tendons are passing: • 1st compartment: abductor pollicis longus & extensor pollicis brevis tendons • 2nd compartment: extensor carpi radialis longus & brevis tendons • 3rd compartment: extensor pollicis longus tendon • 4th compartment: extensor indicis tendon, extensor digitorum tendon, anterior interosseous artery & posterior interosseous nerve • 5th compartment: extensor digiti minimi tendon • 6th compartment: extensor carpi ulnaris tendon © Dr.N.Mugunthan
- 8. Anatomical snuff box Boundaries: •Medial: tendon of extensor pollicis longus • Lateral: tendon of abductor pollicis longus & extensor pollicis brevis • Floor : styloid process of radius, scaphoid & base of 1st metacarpal • Roof : skin , superficial fascia which contains cephalic vein & deep fascia Contents : • Terminal part of radial artery © Dr.N.Mugunthan
- 9. Dorsal digital expansionof hand © Dr.N.Mugunthan
- 10. Hand • 4 lumbricals Thenarmuscles • 1.Abductor pollicis brevis • 2.Flexor pollicis brevis • 3.Opponens pollicis • *Adductor pollicis (Deep muscle) Hypothenar muscles • 1.Flexor digiti minimi • 2.Opponens digiti minimi • 3.Abductor digiti minimi • *Palmaris brevis (superficial muscle) • 4 Palmar interosseous • 4 Dorsal interosseous © Dr.N.Mugunthan
- 11. Hand cont… • 4lumbricals Thenar muscles • 1.Abductor pollicis brevis • 2.Flexor pollicis brevis • 3.Opponens pollicis • *Adductor pollicis (Deep muscle) Hypothenar muscles • 1.Flexor digiti minimi • 2.Opponens digiti minimi • 3.Abductor digiti minimi • *Palmaris brevis (superficial muscle) • 4 Palmar interosseous • 4 Dorsal interosseous © Dr.N.Mugunthan
- 12. Hand cont… • 4lumbricals Thenar muscles • 1.Abductor pollicis brevis • 2.Flexor pollicis brevis • 3.Opponens pollicis • *Adductor pollicis (Deep muscle) Hypothenar muscles • 1.Flexor digiti minimi • 2.Opponens digiti minimi • 3.Abductor digiti minimi • *Palmaris brevis (superficial muscle) • 4 Palmar interosseous • 4 Dorsal interosseous © Dr.N.Mugunthan
- 13. Hand cont… • 4lumbricals Thenar muscles • 1.Abductor pollicis brevis • 2.Flexor pollicis brevis • 3.Opponens pollicis • *Adductor pollicis (Deep muscle) Hypothenar muscles • 1.Flexor digiti minimi • 2.Opponens digiti minimi • 3.Abductor digiti minimi • *Palmaris brevis (superficial muscle) • 4 Palmar interosseous • 4 Dorsal interosseous © Dr.N.Mugunthan
- 14. Hand cont… • 4lumbricals Thenar muscles • 1.Abductor pollicis brevis • 2.Flexor pollicis brevis • 3.Opponens pollicis • *Adductor pollicis (Deep muscle) Hypothenar muscles • 1.Flexor digiti minimi • 2.Opponens digiti minimi • 3.Abductor digiti minimi • *Palmaris brevis (superficial muscle) • 4 Palmar interosseous • 4 Dorsal interosseous © Dr.N.Mugunthan
- 15. Dorsal digital expansion •*Each extensor tendon covers the dorsal surface of head of metacarpal and proximal phalanx and forms triangular shaped dorsal digital expansion • Base: expansions forms a hood over metacarpal head • Apex: expansion at the distal end of proximal phalanx trifurcates into a median and two lateral bands. © Dr.N.Mugunthan
- 16. • Lateral margin:expansions of lateral margin receives the tendon of both lumbrical & interosseous • Medial margin: expansions of medial margin receives the tendon of interosseous only • Proximal wing tendons: contributed by palmar & dorsal interosseous tendons (join close to MCP joint) • Distal wing tendons: contributed by tendon of lumbricals (join close to proximal IP joint) Dorsal digital expansion cont…. © Dr.N.Mugunthan
- 17. Summary Extensor retinaculum • Attachments •6 compartments • Structures passing deep to it Dorsal digital expansion • Formation © Dr.N.Mugunthan