BMS271 - Forearm + Wrist

Question 1

Pronator Teres

Answer 1

Attachments:
- superior medial epicondyle (humeral head), coronoid process (ulnar head)
- middle part of lateral surface of radius
Actions:
- pronation of forearm 
- weak flexion of forearm
Innervation:
- median nerve (C6 and C7)

Question 2

Flexor Carpi Radialis

Answer 2

Attachments:
- medial epicondyle of humerus
- base of 2nd metacarpal
Actions:
- flexes hand at wrist 
- abducts hand at wrist
Innervation:
- median nerve (C6, C7)

Question 3

Palmaris Longus

Answer 3

Attachments:
- medial epicondyle of humerus
- flexor retinaculum, palmar aponeurosis
Absent unilaterally or bilaterally in 14% of people
Actions:
- flexes hand at wrist (weakly) 
- tenses palmar aponeurosis
Innervation:
- median nerve (C7 and C8)

Question 4

Flexor Carpi Ulnaris

Answer 4

Attachments:
- humeral head: medial epicondyle
- ulnar head: olecranon and posterior border
pisiform, hamate, 5th metacarpal
Actions:
- flexes hand at wrist
- adducts hand at wrist
Innervation: 
- ulnar nerve (C7 and C8)

Question 5

Flexor Digitorum Superficialis

Answer 5

Attachments:
- humeroulnar head: medial epicondyle of humerus, coronoid process
- radial head: superior half of anterior border of radius
- shafts of middle phalanges 2 - 5
Actions:
- flexes middle and proximal phalanges
Innervation:
- median nerve (C7, C8 and T1)

Question 6

Flexor Digitorum Profundus

Answer 6

Attachments:
- proximal 3/4 of anterior and medial aspect of ulna, interosseus membrane
- bases of distal phalanges of digits 2 - 5
Actions:
- flexes distal phalanges
Innervation:
- medial half: ulnar nerve (C8 and T1)
- lateral half: median nerve (C8 and T1)

Question 7

Flexor Pollicis Longus

Answer 7

Attachments:
- anterior surface of radius and interosseus membrane
- base of 1st distal phalanx
Actions:
- flexion of phalanges of digit 1
Innervation:
- median nerve (C8 and T1)

Question 8

Pronator Quadratus

Answer 8

Attachments:
- distal 1/4 of anterior surface of ulna
- distal 1/4 of anterior surface of radius
Actions:
- pronation of forearm
Innervation:
- median nerve (C8 and T1)

Question 9

Brachioradialis

Answer 9

Attachments:
- proximal 2/3 of lateral supracondylar ridge
- lateral, distal radius, proximal to styloid process
Actions:
- flexion of forearm at elbow
Innervation:
- radial nerve (C5, C6 and C7)

Question 10

Extensor Carpi Radialis Longus

Answer 10

Attachments:
- lateral supracondylar ridge
- base of 2nd metacarpal
Actions:
- extension of hand at wrist
- abduction of hand at wrist
Innervation:
- radial nerve (C6 and C7)

Question 11

Extensor Carpi Radialis Brevis

Answer 11

Attachments:
- lateral epicondyle
- base of 3rd metacarpal
Actions:
- extension of hand at wrist
- abduction of hand at wrist
Innervation:
- deep branch of radial nerve (C7 and C8)

Question 12

Extensor Digitorum

Answer 12

Attachments:
- lateral epicondyle of humerus
- extensor expansion of digits 2-5
Actions:
- extension of digits 2-5
Innervation:
- deep branch of radial nerve (C7 and C8)

Question 13

Extensor Digiti Minimi

Answer 13

Attachments:
- lateral epicondyle of humerus
- extensor expansion of digit 5
Actions:
- extends digit 5
Innervation:
- deep branch of radial nerve (C7 and C8)

Question 14

Extensor Carpi Ulnaris

Answer 14

Attachments:
- lateral epicondyle of humerus and posterior border of ulna
- base of 5th metacarpal
Actions:
- extends hand at wrist
- adducts hand at wrist
Innervation:
- deep branch of radial nerve (C7 and C8)

Question 15

Anconeus

Answer 15

Attachments:
- lateral epicondyle of humerus
- lateral surface of olecranon and superior, posterior surface of ulna
Actions:
- assists in extension of the forearm at the elbow
Innervation:
- radial nerve (C7, C8 and T1)

Question 16

Supinator

Answer 16

Attachments:
- lateral epicondyle of humerus, radial collateral ligament, annular ligament, supinator fossa, crest of ulna
- lateral, anterior and posterior surfaces of proximal third of radius
Actions:
- supination of forearm
Innervation:
- deep branch of radial nerve (C7 and C8)

Question 17

Abductor Pollicis Longus

Answer 17

Attachments:
- posterior surfaces of radius, ulna and interosseous membrane
- base of 1st metacarpal
Actions:
- abducts 1st digit at carpometacarpal joint
- extends 1st digit at carpometacarpal joint
Innervation:
- posterior interosseous nerve (C7 and C8)

Question 18

Extensor Pollicis Brevis

Answer 18

Attachments:
- posterior surface of radius and interosseous membrane
- base of 1st proximal phalanx
Actions:
- extension of 1st proximal phalanx
Innervation:
- posterior interosseous nerve (C7 and C8)

Question 19

Extensor Pollicis Longus

Answer 19

Attachments:
- posterior surface of ulna and interosseous membrane
- base of 1st distal phalanx
Actions:
- extends distal phalanx of 1st digit
- extends 1st proximal phalanx and 1st metacarpal
Innervation:
- posterior interosseous nerve (C7 and C8)

Question 20

Extensor Indicis

Answer 20

Attachments:
- posterior surface of ulna and interosseous membrane
- extensor expansion of 2nd digit
Actions:
- extends 2nd digit
- assists extension of hand at wrist
Innervation:
- posterior interosseous nerve (C7 and C8)

Question 21

Wrist Joint

Answer 21

• Sometimes referred to as radiocarpal joint
• Distal articular surface of radius articulates with the scaphoid and lunate bones
• Triangular articular disc articulates with triquetrum
• Condyloid joint allows flexion-extension, abduction-adduction and circumduction
• Combination of this joint and midcarpal joint allows for adjustment of length-tension relationship in forearm muscles

Question 22

Intercarpal Joints

Answer 22

• Plane synovial joints
• allow gliding
  Midcarpal joint
• joint between proximal and distal rows
• condyloid joint with distal row presenting a convex surface to the concave proximal row
• Distal row tightly bound to each other
• Forces approximately equally distributed b/w 4 articulations (STT, SC, LC, TH)
• Ligaments important for stability

Question 23

Movements at Wrist and Midcarpal Joint

Answer 23

More flexion than extension possible
Much variation between individuals
105° flexion, 95° extension
for most activities of daily living 10° flexion and 35° extension will be enough
Movement at midcarpal joint initially
Adduction mostly at wrist joint
Abduction mostly at midcarpal joint