L14_The Intrinsic Hand Flashcards
Identify number 1 and number 2 on the picture
- Thenar eminence (thumb)
- Hypothenar eminence (smaller, digit 5)
What’s the palmar aponeurosis?
A triangle of deep fascia that covers the palm, anchored to the skin
Flexor Retinaculum (function, location)
- Creates the carpal tunnel and prevents bowing of the flexors of the forearm (in the anterior compartment of the hand)
- Ligamentous band stretching from pisiform and hook of the hamate to the trapezium and scaphoid
Describe the carpal tunnel (contents, syndrome, location)
● Contents: tendons of FDS (4), tendons of FDP (4), tendon of flexor pollicis longus (1), median n.
● Carpal Tunnel Syndrome: Inflammation and/or increased pressure within the tunnel causes impingement of the median nerve that can result in numbness and weakness in the hand.
● It’s the whole created by the flexor retinaculum where the carpal tunnel is and where the flexor muscles can pass through
Describe de Gyon’s Canal
● Sits superficial to the carpal’s tunnel
● Flexor retinaculum provides floor of the Guyon’s Canal
● Contents: Ulnar a. and n
Muscles from the Thenar Compartment (muscles of the thumb)
Abductor Pollicis Brevis (Origin, Insertion, Functions, Innervation)
Origin: Flexor retinaculum scaphoid, trapezium
Insertion: Base of proximal 1st phalanx
Functions: abducts the thumb
Innervation: recurrent branch of median nerve (C8-T1)
Muscles from the Thenar Compartment (muscles of the thumb)
Flexor Pollicis Brevis (Origin, Insertion, Functions, Innervation)
Origin: Flexor retinaculum trapezium
Insertion: Proximal 1st phalanx
Functions: Flexion at the CMC and MCP joints of the thumb
Innervation: recurrent branch of the median nerve (C8-T1)
Muscles from the Thenar Compartment (muscles of the thumb)
Opponens Pollicis (Origin, Insertion, Functions, Innervation)
Origin: Flexor retinaculum trapezium
Insertion: Shaft of 1st metacarpal
Functions: opposes the thumb
Innervation: Recurrent branch of the median nerve (C8-T1)
Where is the Recurrent branch of the median nerve
The median nerve passes through the carpal tunnel and then a branch (the recurrent branch of the median nerve) splits and goes to the lateral side of the hand (the thumb)
Muscles from the Thenar Compartment (muscles of the thumb)
Adductor Pollicis (Origin, Insertion, Functions, Innervation)
Origin:
Oblique head -> capitate and base of 2nd and 3rd metacarpals
Transverse head -> shaft of 3rd metacarpal
Insertion: Base of proximal phalanx of the thumb
Functions: adducts the thumb
Innervation: deep ulnar nerve (C8-T1) EXCEPTION TO THE RULE
Muscles from the Hypothenar Compartment
Abductor digiti minimi (Origin, Insertion, Functions, Innervation)
Origin: pisiform
Insertion: base of 5th proximal phalanx
Functions: abducts 5th digit
Innervation: Deep ulnar nerve (C8-T1)
Muscles from the Hypothenar Compartment
Flexor digiti minimi Brevis (Origin, Insertion, Functions, Innervation
Origin: Hook of hamate and flexor retinaculum
Insertion: 5th proximal phalanx
Functions: flexion at the CMC and MCP of 5th digit
Innervation: deep ulnar nerve (C8-T1)
Muscles from the Hypothenar Compartment
Opponens digiti minimi (Origin, Insertion, Functions, Innervation
Origin: hook of hamate and flexor retinaculum
Insertion: shaft of 5th metacarpal
functions: opposes 5th digit
Innervation: deep ulnar nerve (C8-T1)
Where is the deep ulnar nerve?
The ulnar nerve passes through the guyon’s canal and then the deep ulnar nerve splits (same thing for the ulnar artery)
Muscles from the Central Compartment
Lumbricals 1-4 (Origin, Insertion, Functions, Innervation
Origin: Radial side of flexor digitorum profundus tendons of digits 2-5
Insertion: Extensor expansion on radial side of proximal phalanges of digits 2-5
Functions: Concurent flexion of MCP and extension of IP joints of digits 2-5
Innervation: Median nerve (C8-T1) for lumbricals I-II, Deep ulnar nerve (C8-T1) for lumbricals III-IV
Muscles from the Interosseous (Deep) Compartment
Palmar interossei PAD (3) (Origin, Insertion, Functions, Innervation
Origin: palmar surface of metacarpals II, IV, V
Insertion: Base of proximal phalanx and extensor expansion of medial side of digit II and lateral side of digits IV-V
Functions: Flexion of MCP, extension of IP joints and adduction of digits II, IV, V
Muscles from the Interosseous (Deep) Compartment
Dorsal interossei DAB (4) (Origin, Insertion, Functions, Innervation)
Origin: 2 adjacent metacarpals shafts
Insertion: Base of proximal phalanx and extensor expansion on lateral side (digit 2), lateral and medial side (digit III) and medial side (digit IV)
Functions: Flexion of MCP, extension of IP joints and abduction of digits II, III, IV
Innervation: deep ulnar nerve (C8-T1)
Tell me the divisions of the ulnar nerve for sensory innervation to the hand
- the ulnar nerve passes through the guyon’s canal and splits into deep and superficial branch of ulnar nerve
- the superficial branch of the ulnar nerve (sensory to medial 1.5 digits -V and 1/2 of IV-, motor to palmaris brevis) divides into common digital branches
- the common branches travel on the sides of digit V and 1/2 of digit IV by smaller branches called proper digital branches
Tell me the passage of the median nerve in the hand
- the median nerve passes through the carpal tunnel and splits into the recurrent branch of the median nerve (give motor innervation to the thenar compartement except adductor pollicis) and the digital branches of the median nerve (give sensory to lateral 3.5 digits (digits I, II, III and 1/2 IV))
- The motor branches in the digits are a division from the digital branches of the median nerve. (they provide motor innervation to lumbricals I and II)
Sensory innervation to the dorsum of the hand…
Radial nerve superficial branche
Ulnar nerve dorsal branch
Median nerve
Motor innervation of the hand …
Median nerve: provides motor innervation to lateral 2 lumbricals
Recurrent branch of median nerve: provides motor innervation to the thenar eminence muscles except adductor pollicis
Deep ulnar nerve: provides motor innervation to the hypothernar eminence, medial 2 lumbricals (IV and V), adductor pollicis, interossei
Explain the vascular supply to the hand (anterior side)
Ulnar:
- Blood comes from the ulnar artery and divides into the superficial palmar arch and the common palmar digital arteries
- The common palmar digital arteries end in proper palmar digital arteries on each side of the digits
- The superficial palmar arch does an arch on the palm of the hand an also divides it self in other common palmar digital arteries.
- The blood from the superficial palmar arch merge with the superficial palmar branch of radial artery (comes from the radial artery) to ensure bllod innervation to the entirety of the hand
Radial:
- The radial artery divides in the deep palmar arch, the principis pollicis digital artery and the radial indicis artery (travels posterior to the thumb)
- The deep palmar arch travels underneath the superficial palmar arch and is closed off by the deep ulnar artery
- The principis pollicis digital artery gives blood supply to the thumb and the radial indicis artery gives blood supply to the digits.
Explain the vascular supply to the hand (posterior side)
- The radial artery divides into the dorsal carpal arch, the principis pollicis artery and the radial indicis artery
- The dorsal carpal arch divides with dorsal metacarpal artery and does an anastomosis of radial and ulnar arteries
- the principis pollicis artery, the radial indicis artery and the dorsal metacarpal artery have dorsal digital arteries in the digits.
The myotomes of the upper limb so far (13)
