Anatomy Of The Hand

Front 1

A Fracture of the hamate could damage what neurovascular structures?

Back 1

The ulnar nerve and artery

Front 2

What makes up Guyon's canal and what nerve can be compressed there?

Back 2

It is formed by a bridge of the pisohamate ligament, the hook of the hamate, and the pisiform. The ulnar nerve and artery can be compressed here,

Front 3

What is a Bennett's Fracture?

Back 3

A fracture of the base of the metacarpal of the thumb

Front 4

What is a Boxer's Fracture?

Back 4

A fracture of the necks of the second and third metacarpals in professional boxers and the fifth metacarpal in unskilled boxers

Front 5

Describe the ossification pattern of the carpal bones of the hand. When do all fuse?

Back 5

Ossification begins at the capitate by 1YEAR of age and proceeds in a counterclockwise direction, according to posteroanterior radiographs of the left hand.

▪Hamate is the second carpus to ossify by age 2
▪Triquetrum by age 3 years
▪Lunate by age 4
▪Scaphoid by age 5 years
▪Trapezium by age 6 years
▪Trapezoid by age 7 years
▪Pisiform, which is a large sesamoid bone, is the last to ossify by age 9 years

All fuse by the age of 14-16

Front 6

Describe the ossification centers of the metacarpals. What's the difference with the first MC?

Back 6

Metacarpals have 2 ossification centers:

One for the body (primary ossification center) which ossifies at 8 weeks, just like most long bones

One at the neck which usually appears before 3 years of age

First metacarpal is a primordial phalanx, and its secondary ossification center is located at the base (like those of the phalanges).

Front 7

Describe the ossification centers for the phalanges.

Back 7

All have 3 secondary ossification centers:
Proximal: Age 3
Middle: Age 4
Distal: Age 5

Front 8

Compare the shapes of the proximal vs vs middle vs distal phalanges.

Back 8

▪ Bases of the proximal phalanges are oval and concave, with the smaller heads ending in two condyles.

▪ Middle phalanges have two concave facets at their bases and pulley-shaped heads.

▪ Distal phalanges are smaller and have palmar ungual tuberosities distally

Front 9

What are some distinctive features of each metacarpal?

Back 9

I (Thumb) Short, stout; base is saddle-shaped
II (Index) Longest, largest base; medial at base
III (Middle) Styloid process
IV (Ring) Small quadrilateral base, narrow shaft
V (Small) Tubercle at base (extensor carpi ulnaris)

Front 10

What bones make up the wrist joint?

Back 10

Radius, Scaphoid, Lunate, Triquetrium

Front 11

What is the strongest supporting structure of the wrist and where does it have a weak spot?

Back 11

The palmar/volar radiocarpal ligament is the strongest supporting structure, although it has a weak area on the radial side (the space of Poirier) that lends less support to the scaphoid, lunate, and trapezoid

Front 12

Two dorsal intercarpal ligaments connect the scaphoid and lunate and the lunate and triquetral bones.

Two palmar intercarpal ligaments connect the scaphoid and lunate and the lunate and triquetral bones.

Which of these is stronger?

Back 12

The dorsal intercarpal ligaments are stronger

Front 13

Are the intercarpal ligaments of the distal or proximal row stronger and thicker?

Back 13

Interosseous ligaments are much thicker in the distal row, connecting the capitate and hamate (strongest), the capitate and trapezoid, and the trapezium and trapezoid (weakest).

Front 14

What is found in the following dorsal compartment of the wrist:
1st

Back 14

APL, EPB

Front 15

What is found in the following dorsal compartment of the wrist:
2nd

Back 15

ECRL, ECRB

Front 16

What is found in the following dorsal compartment of the wrist:
3rd

Back 16

EPL

Front 17

What is found in the following dorsal compartment of the wrist:
4th

Back 17

EDC

Front 18

What is found in the following dorsal compartment of the wrist:
5th

Back 18

EDM (Extensor Digiti Minimi)

Front 19

What is found in the following dorsal compartment of the wrist:
6th

Back 19

ECU

Front 20

What is the orientation of the APL and EPB in the first dorsal compartment? What is important to be aware of with the APL when performing a release for DeQuervain's Tenosynovitis?

Back 20

The APL is radial to the EPB

The APL frequently has multiple tendon slips, which should be addressed during release for de Quervain's tenosynovitis

Front 21

What is the orientation of the ECRL and ECRB in the 2nd dorsal compartment?

Back 21

In the second dorsal compartment, the ECRL tendon is radial to the ECRB tendon. **Thus, the EPL tendon is ulnar to the ECRB tendon at the wrist level** and then crosses over to its insertion distal to the wrist

Front 22

The tendons of which dorsal compartment make up the anatomic snuffbox?

Back 22

The anatomic snuffbox is bordered by tendons of the first and third dorsal wrist compartments; the EPB tendon (1st) serves as the radial snuffbox border, and the EPL tendon (3rd) serves as the ulnar border.

Front 23

In which dorsal wrist compartment is the PIN found?

Back 23

The posterior interosseous nerve is contained within the floor of the fourth dorsal wrist compartment (with the EDC)

Front 24

What forms the roof of the carpal tunnel? What are its attachments?

Back 24

Transverse carpal ligament

It is attached medially to the pisiform and the hook of the hamate and laterally to the tuberosity of the scaphoid and the ridge of the trapezium

Front 25

What 10 structures are found within the carpal tunnel?

Back 25

Median Nerve
9 tendons: 4 of FDS, 4 of FDP, and FPL

Front 26

In the carpal tunnel, what is the relationship of the 4 FDS tendons?

Back 26

In the tunnel, the FDS tendons of the middle and ring fingers are volar to the tendons of the index and small fingers.

Front 27

What are the components of the TFCC?

Back 27

This complex is formed by the triangular fibrocartilage, ulnocarpal ligaments (volar ulnolunate and ulnotriquetral ligaments), and a meniscal homolog

Front 28

What are the 4 components of the intrinsic apparatus of each digit?

Back 28

Sagittal Bands
Transverse Bands
Lateral Bands
Oblique Retinacular Ligament

Front 29

What is the attachment and significance of the following intrinsic apparatus component?
Sagittal Bands

Back 29

Attachment: Covers MCP joint
Significance: Allows MCP extension

Front 30

What is the attachment and significance of the following intrinsic apparatus component?
Transverse Bands

Back 30

Attachment: Volar plate fibers
Significance Allows MCP flexion (interossei)

Front 31

What is the attachment and significance of the following intrinsic apparatus component?
Lateral Bands

Back 31

Attachment: Covers PIP joint
Significance: Allows PIP extension (lumbrical muscles)

Front 32

What is the attachment and significance of the following intrinsic apparatus component?
Oblique Retinacular Ligament

Back 32

Attachment: A4 pulley, terminal tendon
Significance: Allows DIP extension (passive)

Front 33

The flexor sheath covers the flexor tendons in the finger providing protection and nourishment. How is the nourishment provided?

Back 33

Via the Vincula

Front 34

What is unique about the origination of the annular pulleys?

Back 34

A2 and A4 pulleys (even from bone) originate from bone, whereas A1, A3, and A5 pulleys originate from the palmar plates of the metacarpal, proximal interphalangeal, and distal interphalangeal joints (odd from palmar plates).

Front 35

Which 2 hand pulleys are the most critical to function and where are these located?

Back 35

The A2 pulley, overlying the proximal phalanx, is the most critical to function, followed by A4, which covers the middle phalanx

Front 36

The C1 pulley is found between which 2 annular pulleys?

Back 36

A2 & A3. Then they alternate (C2 between A3 & A4, C3 between A4 & A5)

Front 37

The median nerve enters the wrist between what 2 muscles?

Back 37

Flexor Digitorum Superficialis
Flexor Carpi Radialis

Front 38

Does the palmar cutaneous branch of the median nerve arise proximal or distal to the transcarpal ligament? What 2 muscles does it branch between?

Back 38

Arises proximal to the TCL between the palmaris longus and FCR

Front 39

What branch of the median nerve innervates the lumbricals?

Back 39

The digital nerves

Front 40

The ulnar nerve enters the wrist through ____and divides into a superficial branch (palmaris brevis and skin) and a deep branch. The deep branch travels with the__________ and passes between the _____ and ______, giving off motor branches to the deep musculature (___ (how many) hypothenar muscles, ____ ulnar lumbrical muscles, all interossei, and the _____ pollicis) and terminating in digital nerves for the ulnar one and a half digits.

Back 40

The ulnar nerve enters the wrist through GUYON'S CANAL and divides into a superficial branch (palmaris brevis and skin) and a deep branch. The deep branch travels with the DEEP PALMAR ARCH and passes between the ABDUCTOR DIGITI MINIMI and FLEXOR DIGITI MINIMI BREVIS, giving off motor branches to the deep musculature (THREE hypothenar muscles, TWO ulnar lumbrical muscles, all interossei, and the ADDUCTOR pollicis) and terminating in digital nerves for the ulnar one and a half digits.

Front 41

What are the 5 nerves that provide innervation to the thumb?

Back 41

Lateral antebrachial cutaneous nerve (from musculocutaneous nerve), superficial and dorsal digital branches of the radial nerve, and digital and palmar branches of the median nerve

Front 42

At the wrist, the radial artery reaches the dorsum of the carpus by passing between what 3 structures?

Back 42

(1) the FCR and (2) the APL and EPB tendons (snuffbox).

Front 43

What is the main vessel of the deep palmar arch of the hand?

Back 43

The radial artery

Front 44

What vessel supplies the scaphoid and where does it enter the scaphoid?

Back 44

The dorsal carpal branch of the radial artery enters the scaphoid dorsally and distally

Front 45

Which vessel produces the superficial palmar arch? Which is more distal, the superficial or deep arch?

Back 45

The ulnar artery. At the wrist, the ulnar artery lies on the TCL. It gives off a deep palmar branch (which anastomoses with the deep arch) and then forms the superficial palmar arch (which is distal to the deep arch).

Ulnar=sUperficial

Front 46

Where do the digital arteries arise from? Are they dorsal or volar to the nerves?

Back 46

These arteries arise from the superficial palmar arch and run dorsal to the nerves.

Front 47

What is the interval for the dorsal approach to the wrist?

What structure is at risk during the approach?

Back 47

Between the third and fourth extensor compartments (EPL and EDC)

The interosseous scapholunate ligament can be violated

Front 48

Briefly describe the steps involved in the dorsal approach to the wrist.

Back 48

□ Incise the extensory retinaculum between the third and fourth compartments.
□ Protect and retract these tendons to allow access to the distal radius and the dorsal radiocarpal joint.
□ Transpose the EPL, and incise the dorsal capsule.

Front 49

Where is the initial incision made for a carpal tunnel release and why is this location chosen?

Back 49

Usually made in line with the fourth ray to avoid the palmar cutaneous branch of the median nerve.

Front 50

What is the interval for the Volar (Russe's) approach tot he scaphoid?
Why might you choose to approach through the radial aspect of the FCR sheath?

Back 50

Interval: between the FCR and radial artery

This approach is often easier and protects the radial artery

Front 51

Why might you choose a dorsolateral approach to the scaphoid and what is the interval

Back 51

Using an incision within the anatomic snuffbox (first and third dorsal wrist compartment) helps protect the superficial radial nerve and radial artery (deep).

Front 52

Describe the volar approach (Bunnell's) to the flexor tendons and why are zigzag incisions used?

Back 52

Zigzag incisions across the flexor creases help to expose the flexor sheaths.

Digital sheaths should be avoided.

Front 53

What approach to the digits is good for stabilization of fractures and neurovascular exposure?

Back 53

Midlateral approach

Requires a laterally placed incision at the dorsal extent of the interphalangeal creases
▪ Exposure of the digital neurovascular bundle: volar to the incision

Front 54

What are the most commonly used portals for wrist arthroscopy?

Back 54

The placement of portals used for wrist arthroscopy is based on the dorsal compartments. The commonly used 3-4 and 4-5 portals are safe

Front 55

In a 1-2 portal for wrist scoping, what structure is at risk?

Back 55

Radial artery

Front 56

What wrist portals carry the highest risk for damage to nearby structures? What are these structures?

Back 56

6-R portal, and 6-U portal (radial and ulnar to the sixth compartment; risk for injury to the ulnar nerve and artery) carry the highest risk for damage.

Front 57

What is the origin, insertion, action, and innervation for the following hand muscle?
Abductor Pollicis Brevis

Back 57

Origin: Scaphoid, trapezoid
Insertion: Base of proximal phalanx, radial side
Action: Abducting thumb
Innervation: Median nerve (recurrent branch)

Front 58

What is the origin, insertion, action, and innervation for the following hand muscle?
Opponens Pollicis

Back 58

Origin: Trapezium & scaphoid
Insertion: Thumb metacarpal
Action: Abducting, flexing, rotating (medially)
Innervation: Median nerve (recurrent branch)

Front 59

What is the origin, insertion, action, and innervation for the following hand muscle?
Flexor pollicis brevis

Back 59

Origin: Trapezium, scaphoid
Insertion: Base of proximal phalanx, radial side
Action: Flexing MCP joint
Innervation: Median, ulnar nerves

Front 60

What is the origin, insertion, action, and innervation for the following hand muscle?
Adductor Pollicis

Back 60

Origin: Oblique head: bases of 2nd and 3rd metacarpals, capitate, and adjacent carpals; Transverse head: anterior surface of body of 3rd metacarpal
Insertion: Base of proximal phalanx, ulnar side
Action: Adducting thumb
Innervation: Ulnar nerve

Front 61

What is the origin, insertion, action, and innervation for the following hand muscle?
Palmaris Brevis

Back 61

Origin: TCL, palmar aponeurosis
Insertion: Ulnar palm
Action: Retracting skin
Innervation: Ulnar nerve

Front 62

What is the origin, insertion, action, and innervation for the following hand muscle?
Abductor Digiti Minimi

Back 62

Origin: Pisiform
Insertion: Base of proximal phalanx, ulnar side
Action: Abducting small finger
Innervation: Ulnar nerve

Front 63

What is the origin, insertion, action, and innervation for the following hand muscle?
Flexor Digiti Minimi Brevis

Back 63

Origin: Hamate, TCL
Insertion: Base of proximal phalanx, ulnar side
Action: Flexing MCP joint
Innervation: Ulnar nerve

Front 64

What is the origin, insertion, action, and innervation for the following hand muscle?
Opponens digiti minimi

Back 64

Origin: Hamate, TCL
Insertion: Small-finger metacarpal
Action: Abducting, flexing, rotating (laterally)
Innervation: Ulnar nerve

Front 65

What is the origin, insertion, action, and innervation for the following hand muscle?
Lumbricals

Back 65

Origin: FDP tendon
Insertion: Lateral bands (radial)
Action: Extends PIP and DIP
Innervation: Median (1st and 2nd), ulnar nerves (3rd and 4th)

Front 66

What is the origin, insertion, action, and innervation for the following hand muscle?
Palmar interossei

Back 66

Origin: Palmar 1 - 3: Palmar surfaces of 2nd, 4th and 5th metacarpals (unipennate muscles)

Insertion: Palmar 1 - 3: Extensor expansions of digits and bases of proximal phalanges of digits 2, 4 and 5

Action: Palmar 1 - 3: Adduct digits toward axial line and assist lumbricals in flexing metacarpophalangeal joints and extending interphalangeal joints

Innervation: Ulnar nerve

PAD & DAB

Front 67

What is the origin, insertion, action, and innervation for the following hand muscle?
Palmar interossei

Back 67

Origin: Dorsal 1 - 4: Adjacent sides of two metacarpals (bipennate muscles)

Insertion: Dorsal 1 - 4: Extensor expansions and bases of proximal phalanges of digits 2 - 4
Action Dorsal 1 - 4: Abduct digits from axial line and act with lumbricals to flex metacarpophalangeal joints and extend interphalangeal joints

Innervation: Deep branch of ulnar nerve (C8 and T1) (C8, T1)

Arterial Supply: Dorsal 1 - 4: Dorsal and palmar metacarpal arteries

Front 68

What muscles of the hand are innervated by the median nerve?

Back 68

Abductor pollicis brevis, superficial head of flexor pollicis brevis, opponens pollicis, first and second lumbricals

Front 69

What muscles of the hand are innervated by the ulnar nerve?

Back 69

Abductor digiti minimi, opponens digiti minimi, flexor digiti minimi, third and fourth lumbricals, interossei, adductor pollicis, deep head of flexor pollicis brevis

Front 70

Describe a unique attribute of each of the carpal bones:
Capitate
Hamate
Triquetrium
Lunate
Scaphoid
Trapezium
Trapezoid
Pisiform

Back 70

Capitate: Largest carpal bone

Hamate: Has a hook where the transverse carpal ligament and FCR attach

Triquetrium: Triangular/pyramidal in shape

Lunate: Moon-shaped, palmar blood supply so a palmar fx needs ORIF and a dorsal fx is non-op. Dislocations are frequently missed

Scaphoid: Boat-shaped. 80% of surface is articular (note the waist), Has a distal blood supply (radial artery)

Trapezium: Articulates with 1st MC, radial attachment for TCL, has groove for FCR

Trapezoid: Wedge shaped, articulates with 2nd MC

Pisiform: Sesamoid in FCU tendon, spherical