L14_The Intrinsic Hand

Question 1

Identify number 1 and number 2 on the picture

Answer 1

1. Thenar eminence (thumb)
2. Hypothenar eminence (smaller, digit 5)

Question 2

What’s the palmar aponeurosis?

Answer 2

A triangle of deep fascia that covers the palm, anchored to the skin

Question 3

Flexor Retinaculum (function, location)

Answer 3

• 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

Question 4

Describe the carpal tunnel (contents, syndrome, location)

Answer 4

● 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

Question 5

Describe de Gyon’s Canal

Answer 5

● Sits superficial to the carpal’s tunnel

● Flexor retinaculum provides floor of the Guyon’s Canal

● Contents: Ulnar a. and n

Question 6

Muscles from the Thenar Compartment (muscles of the thumb)

Abductor Pollicis Brevis (Origin, Insertion, Functions, Innervation)

Answer 6

Origin: Flexor retinaculum scaphoid, trapezium

Insertion: Base of proximal 1st phalanx

Functions: abducts the thumb

Innervation: recurrent branch of median nerve (C8-T1)

Question 7

Muscles from the Thenar Compartment (muscles of the thumb)

Flexor Pollicis Brevis (Origin, Insertion, Functions, Innervation)

Answer 7

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)

Question 8

Muscles from the Thenar Compartment (muscles of the thumb)

Opponens Pollicis (Origin, Insertion, Functions, Innervation)

Answer 8

Origin: Flexor retinaculum trapezium

Insertion: Shaft of 1st metacarpal

Functions: opposes the thumb

Innervation: Recurrent branch of the median nerve (C8-T1)

Question 9

Where is the Recurrent branch of the median nerve

Answer 9

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)

Question 10

Muscles from the Thenar Compartment (muscles of the thumb)

Adductor Pollicis (Origin, Insertion, Functions, Innervation)

Answer 10

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

Question 11

Muscles from the Hypothenar Compartment

Abductor digiti minimi (Origin, Insertion, Functions, Innervation)

Answer 11

Origin: pisiform

Insertion: base of 5th proximal phalanx

Functions: abducts 5th digit

Innervation: Deep ulnar nerve (C8-T1)

Question 12

Muscles from the Hypothenar Compartment

Flexor digiti minimi Brevis (Origin, Insertion, Functions, Innervation

Answer 12

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)

Question 13

Muscles from the Hypothenar Compartment

Opponens digiti minimi (Origin, Insertion, Functions, Innervation

Answer 13

Origin: hook of hamate and flexor retinaculum

Insertion: shaft of 5th metacarpal

functions: opposes 5th digit

Innervation: deep ulnar nerve (C8-T1)

Question 14

Where is the deep ulnar nerve?

Answer 14

The ulnar nerve passes through the guyon’s canal and then the deep ulnar nerve splits (same thing for the ulnar artery)

Question 15

Muscles from the Central Compartment

Lumbricals 1-4 (Origin, Insertion, Functions, Innervation

Answer 15

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

Question 16

Muscles from the Interosseous (Deep) Compartment

Palmar interossei PAD (3) (Origin, Insertion, Functions, Innervation

Answer 16

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

Question 17

Muscles from the Interosseous (Deep) Compartment

Dorsal interossei DAB (4) (Origin, Insertion, Functions, Innervation)

Answer 17

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)

Question 18

Tell me the divisions of the ulnar nerve for sensory innervation to the hand

Answer 18

1. the ulnar nerve passes through the guyon’s canal and splits into deep and superficial branch of ulnar nerve
2. 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
3. the common branches travel on the sides of digit V and 1/2 of digit IV by smaller branches called proper digital branches

Question 19

Tell me the passage of the median nerve in the hand

Answer 19

1. 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))
2. 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)

Question 20

Sensory innervation to the dorsum of the hand…

Answer 20

Radial nerve superficial branche

Ulnar nerve dorsal branch

Median nerve

Question 21

Motor innervation of the hand …

Answer 21

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

Question 22

Explain the vascular supply to the hand (anterior side)

Answer 22

Ulnar:

1. Blood comes from the ulnar artery and divides into the superficial palmar arch and the common palmar digital arteries
2. The common palmar digital arteries end in proper palmar digital arteries on each side of the digits
3. The superficial palmar arch does an arch on the palm of the hand an also divides it self in other common palmar digital arteries.
4. 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:

1. The radial artery divides in the deep palmar arch, the principis pollicis digital artery and the radial indicis artery (travels posterior to the thumb)
2. The deep palmar arch travels underneath the superficial palmar arch and is closed off by the deep ulnar artery
3. The principis pollicis digital artery gives blood supply to the thumb and the radial indicis artery gives blood supply to the digits.

Question 23

Explain the vascular supply to the hand (posterior side)

Answer 23

1. The radial artery divides into the dorsal carpal arch, the principis pollicis artery and the radial indicis artery
2. The dorsal carpal arch divides with dorsal metacarpal artery and does an anastomosis of radial and ulnar arteries
3. the principis pollicis artery, the radial indicis artery and the dorsal metacarpal artery have dorsal digital arteries in the digits.

Question 24

The myotomes of the upper limb so far (13)

Answer 24