Mod 2: Lecture 4 - Forearm and Wrist

Question 1

Axillary Artery —>____

Answer 1

• brachial artery
• at the inferior border of the teres major muscle, the axillary artery changes name to become the brachial artery
• subclavian –> axillary –> brachial

Question 2

Brachial Artery

Answer 2

• Brachial Profunda
• — a branch of the brachial artery that comes off in the upper arm
• — runs deep into the arm to supply the deep tissue/muscle
• Terminal Branches: where the brachial artery splits at the elbow region
• — Radial Artery
• — Ulnar Artery
• — these run into the forearm

Question 3

Ulnar Artery Branches

Answer 3

• common interosseous artery branches off the ulna
• common interosseous artery –> anterior interosseous artery + posterior interosseous artery
• — supply the deep tissue/muscle of the forearm

Question 4

Elbow anastomosis formed by….

Answer 4

• ulnar collaterals (vessels from the ulnar artery)
• radial and ulnar recurrent arteries
• ensures a good blood flow to the arm at all times

Question 5

Superficial Palmar Arch

Answer 5

• formed from the ulnar artery as it goes into the hand
• a curve of vessel in the palm that is closer to the fingers than the wrist
• vessels coming off of it
• — supply 2 vessels each to the pinky, ring, and middle finger
• — supply 1 vessel to the index finger

Question 6

Deep Palmar Arch

Answer 6

• formed by the radial artery
• vessels coming off of it
• — supply 2 vessels to the thumb
• — supply 1 vessel to the index finger
• a curve of vessel in the palm that is closer to the wrist than fingers

Question 7

Upper Extremity: Venous Drainage

Answer 7

• a dorsal venous network drains the superficial and deep venous palmar arches
• — back of the hand
• superficial to the metacarpus , the network is prolonged proximally
• — the network goes just above the wrist where it enters into other veins
• — lateral side (thumb side): cephalic vein
• — medial side (pinky side): basilic vein

Question 8

Basilic and Cephalic veins –>

Answer 8

• Median cubital vein is the communication between the basilic and cephalic veins in the cubital fossa
• — the median cubital vein branches across the arm at the elbow to connect these two parallel veins
• Basilic –> origin of the axillary vein
• Cephalic –> termination of the axillary vein

Question 9

The radial and ulnar styloids limit ____

Answer 9

• lateral deviation of the wrist

- the styloids are the pointed projections on the distal end of the bones

Question 10

Clinical Correlation: Colle’s Fracture

Answer 10

• 70% in post-menopausal women
• — protective effect on bone density of estrogen
• — so old ladies are more likely to fall and try to break it with their hands
• — but they end up snapping their wrist
• distal radius fracture with dorsal displacement of distal fragment
• — the end of the radius breaks and is pushed up toward the dorsal side of the hand/wrist

Question 11

Clinical Correlation: Smith Fracture

Answer 11

• reverse of Colle’s fracture
• occurs when there is force to a flexed wrist
• — such as in sports if a player falls while holding a ball and lands on the back of his wrist
• distal radius fracture with palmar displacement of distal fragment
• — the end of the radius breaks and is pushed up toward the palmar side of the hand/wrist

Question 12

Carpal Bones

Answer 12

• Two Rows: Proximal and Distal
• — “So Long to Pinky, Here Comes The Thumb”
• — clockwise from thumb on volar surface, beginning in proximal row
• carpal bones are very tightly packed, close proximity to each other
• distal radial articulates with the carpals
• distal ulna does not articulate with them

Question 13

Proximal Row Of Carpal Bones

Answer 13

• Proximal row approximates with the radius
• — is closer to arm
• —- scaphoid, lunate, triquetrum, pisiform ( Lat- Med)
• — the scaphoid is on the thumb side
• — you cannot see the pisiform from the dorsal surface of the hand, you can only see it in a palmar view
• “So Long to Pinky,…”

Question 14

Distal Row of Carpal Bones

Answer 14

• Distal row approximates with metacarpals
• — is closer to fingers
• — hammate, capitate, trapezoid, trapezium (Med - Lat)
• — hammate is under the pinky bc this little piggy goes to the market
• “…. Here Comes The Thumb.”

Question 15

Hand Osteology

Answer 15

1. Styloid Process of Radius
2. Styloid Process of Ulna
3. Metacarpal
4. Proximal Phalange
5. Middle Phalange
6. Distal Phalange

Question 16

Hand Osteology

1. Styloid Process of Radius
2. Styloid Process of Ulna
3. Metacarpal

Answer 16

1. tip of the triangular distal end of the radius
2. little pointed thing sticking out of the distal end of the ulna
3. bones in the hand, distal to the carpals, proximal to the phalanges
   - there are 5, one connecting each finger to the wrist
   - — numbered from 1 to 5, starting with the thumb (1) and ending in the pinky (5)
   - each has a base (proximal end) and head (distal end)

Question 17

Hand Osteology

4. Proximal Phalange
5. Middle Phalange
6. Distal Phalange

Answer 17

4. the row of phalanges that is closest to the metacarpals
   - — there are 5 of them, one in each finger
5. the row of phalanges that is in between the proximal and distal phalanges
   - — where the middle knuckle in your fingers is
   - — there are 4 of them, one in each finger except the thumb
6. the tips of the fingers, after the last knuckle
   - — small little bones
   - — there are 5 of them, one in each finger

Question 18

Palmar Arches

Answer 18

• formed by bony structures, ligaments
• Two Transverse Arches
• One Longitudinal Arch
• Functions:
• — balance stability and mobility –> arches are stable structure
• — increase surface contact of palm –> more sensory feedback
• — position thumb for function –> put thumb in opposition to fingers

Question 19

Transverse Palmar Arches

Answer 19

• there are two
• Proximal: runs across the bases of the metacarpals
• Distal: runs across the heads of the metacarpals

Question 20

Longitudinal Palmar Arch

Answer 20

• only one

- runs through the long axis (from wrist to fingertip) of the third digit (middle finger)

Question 21

Articulations: Radiocarpal

Answer 21

• between distal radius and proximal carpals
• condyloid type
• — moves in two planes
• wrist flexion/extension
• — sagittal plane, bending forward and back
• wrist abduction and adduction
• — coronal plane, moving sideways in and out (right and left)

Question 22

Articulations: Midcarpal

Answer 22

• between proximal and distal row of carpal bones
• plane synovial joint
• gliding motions between carpals

Question 23

Arthrokinematics:

1. Flexing the wrist down, like reaching into a bag of chips
2. Wrist Extension, moving the hand up, fingers point up, like going for a high five (without raising your arm)

Answer 23

• full range of motion at the wrist requires movement at both the radiocarpal and midcarpal joints
• so for wrist injuries, you must address movement at both joints

1. • 60% radiocarpal movement
     - 40% midcarpal movement
2. • 40% radiocarpal movement
     - 60% midcarpal movement

Question 24

Distal Radioulnar Joint

Answer 24

• between the distal ends of the radius and ulna
• pivot synovial joint
• supination/pronation
• separated from the joint space of the radiocarpal joint by an articular disc

Question 25

Stabilizing Ligaments

Answer 25

• Collateral Ligaments

- Retinaculum Ligaments

Question 26

Collateral Ligaments

Answer 26

• stabilizing ligaments
• Radial Collateral Ligament
• — between radius and carpals
• — on the side of the first digit (thumb)
• — prevents deviation to the ulnar side/ pinky
• Ulnar Collateral Ligament
• — between the ulna and carpals
• — prevents deviation toward the radial side/thumb

Question 27

Retinaculum Ligaments

Answer 27

• stabilizing ligaments
• broad bands of fibrous connective tissue that stabilize the wrist and prevent “bowstringing” of the tendons of extrinsic muscles of the hand
• Extensor Retinaculum: dorsal
• Flexor Retinaculum: ventral

Question 28

Extensor Retinaculum Ligament

Answer 28

• dorsal side of wrist
• from distal radius to pisiform and triquetrum
• horizontally across the proximal end of the wrist

Question 29

Flexor Retinaculum Ligament

Answer 29

• ventral side of wrist
• from pisiform and hammate to scaphoid and trapezium
• horizontally across the middle of the carpal bones

Question 30

Carpal Tunnel

Answer 30

• anatomical space between the flexor retinaculum ligament and the carpal bones
• tendons of some muscles (FDS, FDP, FPL) and the main branch of the median nerve pass through the carpal tunnel
• — one branch of the median nerve (palmar cutaneous branch) does not pass through
• ulnar nerve and artery do not pass through the tunnel

Question 31

Muscles Acting on the Wrist: Extensors

Answer 31

• Extensor Carpi Radialis Longus (Radial Nerve)
• Extensor Carpi Radialis Brevis (Radial)
• Extensor Carpi Ulnaris (Radial)
• all three are in the posterior compartment, so innervated by the same nerve

Question 32

Muscles Acting on the Wrist: Flexors

Answer 32

• Anterior Compartment
• — main flexors of the wrist
• — Flexor Carpi Radialis (Median)
• — Flexor Carpi Ulnaris (Ulnar)
• Palmaris Longus (Median)
• — absent in 10 - 25% of people
• — weak flexor of the wrist

Question 33

Muscles Acting on the Wrist: Extensors

1. Attachments
2. Action
3. Innervation

Answer 33

1. • lateral epicondyle of humerus (thumb side)
     - base of metacarpals
     - — ECRL: 2nd metacarpal
     - — ECRB: 3rd
     - — ECU: 5th
2. wrist extension
3. radial nerve

Question 34

Clinical Note: Lateral Epicondylitis

Answer 34

• repeated forceful flexion and extension of the wrist may strain the attachment of the common extensor tendon
• — flexion: muscle stretches
• — extension: muscle contracts
• — attachment: lateral epicondyle of humerus
• producing inflammation of the periosteum of the lateral epicondyle
• — lateral epicondylitis
• test by resisting wrist extension while pushing on lateral condyle at elbow

Question 35

Muscles Acting on the Wrist: Flexors

1. Attachements
2. Action
3. Innervation

Answer 35

1. • medial epicondyle of the humerus (pinky side)
     - FCR/FCU: base of metacarpals
     - PL: fascia of the palm, over the metacarpals
2. wrist flexion
3. • FCR: median
     - FCU: ulnar
     - PL: median

Question 36

Clinical Correlation: Dupuytren’s Contracture

Answer 36

• a benign, slowly progressive condition causing contracture (or shrinking) of the palmar fascia
• — makes it impossible to fully extend the hand
• — needs to have the tissue surgically extended to gain full motion
• has no clear etiology or pathogenesis
• may be hereditary
• — commonly present in males of Irish/Welsh descent

Question 37

1. Wrist Abduction

2. Wrist Adduction

Answer 37

1. • Radial Deviation
     - — coronal plane, swinging the wrist out to the lateral side
     - occurs as a result of co-contraction of both the ECRL and FCR
2. • Ulnar Deviation
     - — coronal plane, swinging the wrist in to the medial side
     - occurs as a result of co-contraction of both the ECU and FCU