Posterior Forearm

Question 1

How many bones in the wrist and hand

Answer 1

27 bones in left - 54 in both

Question 2

Carpometacarpal Joint

CMC

Answer 2

Joint between carpal and metacaparpal

Question 3

metacarpal phalangeal joint

MCP

Answer 3

joint between metcarpal and proximal phalanx

Question 4

Proximal interphalangeal joint

PIP

Answer 4

joint between proximal and middle phalanx

Question 5

Distal Interphalangeal Joint

DIP

Answer 5

joint between middle and distal phalanx

Question 6

Extensor retinaculum has ___ compartments

Answer 6

6

Question 7

6 Muscles in the superficial layer

Answer 7

Brachioradialis, Extensor Carpi Radialis Longus, Extensor Carpi Radialis Brevis, Extensor Digitorum Communis, Extensor Digiti Minimi, Extensor Carpi Ulnaris

Question 8

Brachioradialis

Answer 8

Origin: Lateral Supra Condylar Ridge of the humerus (takes origin above elbow)
Insertion: Distal lateral aspect of the radius just proximal to the radial styloid process
Innervated: Radial Nerve
Function: Elbow Flexion especially if the arm is in neutral - assists with supination

Question 9

Extensor Carpi Radialis Longus

Answer 9

Origin: Lateral Supracondyle ridge of the humerus
Insertion: Metacarpal Number 2
Innervated: Radial Nerve
Function: Wrist extension, wrist radial deviation

Question 10

Extensor Carpi Radialis Brevis

Answer 10

Origin: Lateral epicondyle via the common extensor tendon
Insertion: Metacarpal number 3
Runs all the way down the forearm
Innervated: Radial Nerve
Function: Wrist Extension, Wrist radial deviation

Question 11

Extensor Digitorum Communis

Answer 11

Origin: Lateral epicondyle of the humerus via the common extensor tendon
Insertion: (Tendon 1 attached to digit 2, tendon 2 to digit 3, tendon 3 to digit 4, tendon 4 to digit 5) Extensor expansions digits 2-5
EDC has one central slip that inserts on the middle phalanx and two collateral bands that insert on the distal phalnx
Innervated: Radial Nerve
Function: MCP extension - also synergistic for wrist extension

Question 12

Extensor Digiti Minimi

Answer 12

Origin: Lateral epicondyle of the humerus via the common extensor tendon
Insertion: Extensor expansion of digit 5
Innervated: Radial Nerve
Function: Extension of MCP for digit 5

Question 13

Extensor Carpi Ulnaris

Answer 13

Origin: Lateral epicondyle of the humerus via the common extensor tendon and the posterior aspect of the ulna
Insertion: Metacarpal number 5
Innervated: Radial Nerve
Function: Ulna deviation and wrist extension

Question 14

5 muscles in the deep layer

Answer 14

Supinator, abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus, extensor indicis proprius

Question 15

Supinator

Answer 15

Origin: Lateral epicondyle of the humerus, supinator crest (on the posterior ulna)
Insertion: Proximal lateral radius
Innervated: Radial Nerve
Function: Supinates the forearm - when it contracts it spins the radial head

Question 16

Abductor pollicis Longus

Answer 16

Origin: Posterior aspect of the radius, ulna, and interosseus membrane
Insertion: Proximal Phalanx of digit 1
Innervated: Radial Nerve
Function: Adducts the thumb

Question 17

Extensor Pollicis Brevis

Answer 17

Origin: posterior aspect of the radius, ulna, and interroseus membrane
Insertion: Metacarpal number 1
Innervated: Radial Nerve
Function: extends mcp joint of the thumb

Question 18

Extensor Pollicis Longus

Answer 18

Origin: Posterior 1/3 of the ulna and interosseus membrane
Insertion: distal phalanx digit 1
Innervated: Radial Nerve
Function: extends the thumb- main job to extend the IP joint but can extend all joints of the thumb

Question 19

Extensor Indicies Proprious

Answer 19

Origin: Posterior aspect of the ulna and interosseus membrane
Insertion: Extensor Expansions of digit 2
Innervated: Radial Nerve
Function: Extends digit 2 primarily at the mcp joint

Question 20

How does the radial nerve travel

Answer 20

goes around the lateral epicondyle and splits into teh deep and superficial branches - deep branch innervates all 11 muscles and the superficial brings feeling to the back of the hand of digits 1-3 radial part of digit 4 up to the DIP joint