That (Trapezium) They (Trapezoid) Cant (Capitate) Handle (Hamate)
the radius articulates only with the Scaphoid and Lunate. The Ulna does not articulate because of a cartilage disc in between.
5 metacarpal (palm) bones
numbered 1-5; have a distal growth plate (phalanges have proximal growth plates)
14 phalangeal bones
each finger has Distal, Middle, and Proximal except the thumb which only has Distal and Proximal.
fingers are numbered 1 (pollex, "thumb") to 5 (digiti minimi, "pinkie")
4 layers of the anterior compartment
: from the medial epicondyle, innervated primarily by the median nerve.
(1) Brachioradialis (the odd guy, does not cross wrist, innervated by the radial nerve, starts from the lateral epicondyle) Pronator teres, Flexor carpi radialis, Flexor carpi ulnaris (innervated by the ulnar nerve), Palmarus longus.
(2) flexor digitorum superficialis (the tendons of this muscle attach to both sides of the medial (middle) phalanges)
(3) flexor digitorum profundus (1/2 ulnar nerve, attach to the base of the phalanges) and the flexor pollicis longus
The tendons of the flexor digitorum superficialis split and attach on the medial and lateral sides of the middle phalanges. The tendons of the flexor digitorum profundus go through the hole created by the splitting of the flex.dig.superficialis and attach at the base of the distal phalanges. The only muscle crossing the DIP is the flexor digitorum profundus.
Interossei muscles
provide stability to the hand. Palmar Adducts, the Dorsal Abducts, the fingers
FAO
in both the thenar and hypothenar regions on the palmar side there is a
F
flexor pollicis brevis (thenar) and flexor digiti minimi (hypo) located medially
A
abductor pollicis brevis (thenar) and abductor digiti minimi (hypo) located beside F
O
opponens pollicis (thenar) and opponens digiti minimi (hypo) located deep to A
The median nerve innervates 5 muscles in the palm (abductor pollicis brevis, superficial head of flexor pollicis brevis, opponens pollicis, and 2 of the lumbrical muscles)
The superficial palmar arch (from the ulnar artery) runs lateral to the pisiform bone
The ulnar nerve is the cutaneous branch on both sides of the pinkie and the medial side of the ring finger
Remember that the adductor pollicis muscle is not a thenar muscle, it is innervated by the ulnar nerve. Thenar muscles are innervated by the recurrent branch of the median nerve.
The pronator quadratus muscle is located distal to the wrist, do not confuse with the flexor retinaculum.
Lumbricals
flex at the MP joint, extend at the PIP and DIP joints. This feature allows them to control fine motor movements at the phalangeal joints.
Layers of the dorsal arm
1stextensor carpi ulnaris and extensor carpi radialis
2nd extensor digitorum and extensor digiti minimi
3rdAnconeus (considered part of the triceps brachii), extensor indicis,
extensor pollicis longus (attaches to the base of the distal phalanx)
extensor pollicis brevis
(attaches to the base of the proximal phalanx)
abductor pollicis longus
(attaches to the base the metacarpal)
Five Motions of the Thumb
extension
hitch-hiker
flexion
folding the thumb across the palm
abduction
the thumb is perpendicular to the palm
adduction
returning the thumb to rest alongside the row of fingers
opposition
when the pad of the thumb is touching the pad of the "pinkie"
Surface Anatomy
Olecranon Process the most proximal portion of the Ulna
Medial Epicondyle
the large prominence on the medial side of the distal humerus
Lateral Epicondyle
the prominence on the lateral side of the distal humerus
Cubital Fossa
the region on the inside angle of the elbow, see D3J Brachial Plexus cont. for the borders and contents
Pisiform Bone
the smallest bone in the wrist, pea shaped sesamoid bone in the tendon of the flexor carpi ulnaris muscle.
Scaphoid Tubercle
the most lateral of the proximal carpal bones (the pisiform is the most medial of the proximal carpal bones), is the Scaphoid. On the scaphoid there is an elevated prominence known as the tubercle.
Flexor Carpi Radialis tendon
the large tendon visible superficially on the lateral (thumb) side of the anterior (volar side) wrist.
Flexor Carpi Ulnaris Tendon
the large tendon visible superficially on the medial (pinkie) side of the volar wrist.
'Snuff-box' a depression on the lateral side of the wrist. The tendons of the abductor pollicis longus and extensor pollicis brevis bound the snuff box anteriorly, the tendon of the extensor pollicis longus bound it posteriorly. Deep to the snuff box lies the scaphoid bone. Localized tenderness in this area is suggestive of a scaphoid fracture.
Dorsal Radial Tubercle on the distal radius; can be felt between the snuff box and the extensor tendons. a.k.a. Listers tubercle. Where the tendon for the extensor pollicis longus changes direction towards the thumb.
Extensor Tendons the tendons that can be visualized on the back of the hand
Head of Ulna sticks out medially from the dorsal side on the wrist (actually the distal ulna)
Radial Styloid Process laterally the distal end of the radius tapers abruptly into a prominent pyramidal styloid process.
Knuckles formed by the heads of the metacarpals
Structures in the Ventral Antebrachium
Brachioradialis
muscle
Median nerve
enters the forearm with the Brachial artery, lies on the brachialis muscle, then passes between the two heads of the Pronator teres muscle, descending deep to the flexor digitorum superficialis, continuing distally to the wrist where it passes superficially between the tendons of the flexor digitorum superficialis and the flexor carpi radialis. The median nerve only has branches in the forearm and hand (articular, muscular, anterior interosseus, and palmar cutaneous) It crosses into the hand through the Carpal Tunnel.
Brachial artery
gives rise to the ulnar and radial arteries when it ends opposite the neck of the radius in the cubital fossa
Flexor Carpi Radialis muscle
Origin
: common flexor tendon from the medial epicondyle of humerus, fascia of forearm
Insertion
: base of 2nd and 3rd metacarpal bones
Function
: flexes wrist, assists in pronating and abducting the hand, assists in flexing the forearm.
Nerve
: Median
Artery
: muscular branch of the radial
Palmaris Longus muscle
Origin
: common flexor tendon from the medial epicondyle of humerus
Insertion
: transverse carpal ligament and palmar aponeurosis
Function
: flexes the wrist, assists in pronation and flexion of the forearm
Nerve
: Median
Artery
: Posterior Ulnar recurrent
Flexor Carpi Ulnaris muscle
Origin
: Humeral head from common flexor tendon from the medial epicondyle of humerus, Ulnar head from the Olecranon and dorsal border of the ulna.
Insertion
: Pisiform, Hamate, 5th metacarpal bones
Function
: flexes wrist and assists in adducting it, also assists in flexing the forearm
Nerve
: Ulnar
Artery
: Posterior Ulnar recurrent
Flexor Digitorum Superficialis muscle
Origin
: Humeral head from the common flexor tendon from the medial epicondyle of the humerus, Ulnar head from the coronoid process of the ulna, Radial head from the oblique line of the radius.
Insertion
: margins of the palmar surface of the middle phalanx of the medial four digits
Function
: flexes the middle and proximal phalanges of the medial 4 digits, aids in flexing the wrist and forearm.
Nerve
: Median
Artery
: muscular branches of the ulnar and the muscular branches of the radial
Flexor Digitorum Profundus muscle
Origin
: the medial and anterior surfaces of the ulna, the interosseous membrane, and the deep fascia of the forearm.
Insertion
: the distal phalanges of the medial four digits
Function
: flexes the terminal phalanges of the medial 4 digits after the superficialis flexes 2nd phalanges, also aids in flexing the wrist.
Nerves
: Ulnar, volar interosseus of median
Arteries
: volar interosseus of ulna, muscular branches of ulna
Ulnar artery
one of the branches of the Brachial artery, passes from the cubital fossa to the medial side of the forearm. With the median nerve, it passes between the ulnar and radial heads of the flexor digitorum superficialis. Leaving the forearm it passes through the canal of Guyon ending in the superficial and deep palmar arches.
Ulnar nerve
after passing posterior to the medial epicondyle of the humerus, the ulnar nerve enters the forearm by passing between the two heads of the flexor carpi ulnaris muscle. In the distal forearm, the ulnar nerve becomes more superficial. It pierces the deep fascia and passes with the ulnar artery superficial to the flexor retinaculum, lateral to the pisiform, between the pisiform and the hook of the hamate in the canal of Guyon. The ulnar has branches in the forearm and hand (Articular, Muscular, palmar cutaneous, and dorsal cutaneous) but none in the arm.
Radial artery
its course can be represented by a line connecting the midpoint of the cubital fossa to a point medial of the styloid process of the radius. The radial artery crosses the Anatomic Snuff box ending in the Deep Palmar Arch.
Common Interosseous artery
a short branch of the ulnar, arises in the distal part of the cubital fossa and gives rise to the Anterior and posterior interosseus arteries.
Anterior Interosseous artery
passes distally on the interosseus membrane, ends in the dorsal carpal arch.
Radial nerve (Superficial branch)-
soon after entering the arm the Radial nerve splits into two terminal branches. The superficial branch is the smaller of the two and is the direct continuation of the Radial nerve. It supplies the skin of the dorsum of the wrist, hand, thumb, and lateral one and one half digits.
Radial nerve (Deep branch)-
entirely muscular in its distribution, supplies the supinator, and extensor carpi radialis brevis in addition to giving many branches to the extensor muscles (one of these branches is the posterior interosseus nerve)
Posterior Interosseous nerve
- branch of the deep radial nerve that accompanies the interosseus artery and supplies the deep extensor muscles (Abductor pollicis longus, Extensor pollicis brevis, Extensor pollicis longus, Extensor indicis)
Flexor Pollicis Longus muscle
Origin
: volar surface of the radius, adjacent interosseus membrane, medial border of coronoid process of ulna.
Insertion
: the base of the distal phalanx of the thumb on the palmar surface
Function
: flexes the thumb
Nerve
: volar interosseus of median
Artery
: volar interosseus of ulna
Pronator Quadratus muscle
Origin
: the distal 4th of the volar surface of the ulna
Insertion
: the distal 4th of the lateral border on the volar surface of the radius
Function
: pronates the forearm
Nerve
: Volar interosseus of the median
Artery
: Volar interosseus of the ulna
Structures in the Dorsal Antebrachium
Extensor Pollicis Longus muscle
Origin
middle 3rd of posterior surface of the Ulna, interosseus membrane
Insertion
base of the distal phalanx of the thumb
Function
extends the terminal phalanx of the thumb
Nerve
posterior interosseus of the radial nerve
Artery
posterior interosseus of the ulna artery
Extensor Pollicis Brevis muscle
Origin
posterior surface of the radius, interosseus membrane
Insertion
base of the proximal phalanx of the thumb
Function
extends the proximal phalanx of the thumb
Nerve
posterior interosseus of the radial
Artery
posterior interosseus of the ulnar
Abductor Pollicis Longus muscle
Origin
posterior surface of the ulna, interosseus membrane, middle 3rd of the posterior surface of the radius
Insertion
radial side of the base of the 1st metacarpal bone
Function
abducts the thumb and wrist
Nerve
posterior interosseus of the radial
Artery
posterior interosseus of the ulnar
Radial artery from the Snuff box, the radial artery gives rise to the radialis indicis (feeds the index finger), the princeps pollicis artery (thumb), and then joins the ulnar artery in the deep palmar arterial arch.
Extensor Retinaculum a fibrous band that holds the extensor tendons in place at the wrist. Prevents "bowstringing"
Extensor Carpi Radialis Longus muscle
Origin
the lower 3rd of the lateral supracondylar ridge of the humerus, the lateral intermuscular septum
Insertion
the dorsal surface of the base of the 2nd metacarpal bone
Function
extends the wrist, abducts the hand
Nerve
radial
Artery
muscular branches of the radial, the radial recurrent
Extensor Carpi Radialis Brevis muscle
Origin
from the common extensor tendon from the lateral epicondyle of the humerus, the radial collateral ligament of the elbow joint, and the intermuscular septa.
Insertion
the dorsal surface of the base of the 3rd metacarpal bone
Function
extends the wrist, abducts the hand
Nerve
the posterior interosseus of the radial
Artery
muscular branches of the radial, the radial recurrent
Extensor Digitorum muscle
Origin
the lateral epicondyle of the humerus by the common extensor tendon, the intermuscular septa
Insertion
the lateral and dorsal surfaces of the phalanges of the medial 4 digits
Function
extends the medial 4 digits, assists in extension of the wrist
Nerve
the posterior interosseus of the radial
Artery
the posterior interosseus of the ulnar
Extensor Carpi Ulnaris muscle
Origin
from the common extensor tendon from the lateral epicondyle of the humerus and from the posterior border of the ulna.
Insertion
the medial side of the base of the 5th metacarpal bone
Function
extends the wrist, adducts the hand
Nerve
the posterior interosseus of the radial
Artery
the posterior interosseus of the ulnar
Extensor Indicus muscle
Origin
the posterior surface of the ulna, the interosseus membrane
Insertion
the dorsum of the proximal phalanx of the index finger
Function
extends the proximal phalanx of the index finger
Nerve
the posterior interosseus of the radial
Artery
the posterior interosseus of the ulnar
Extensor Digiti Minimi muscle
Origin
the common extensor tendon from the lateral epicondyle of the humerus, and the intermuscular septa
Insertion
the dorsum of the proximal phalanx of the 5th digit
Function
extends the 5th digit
Nerve
the posterior interosseus of the radial
Artery
the posterior interosseus of the ulnar
Structures in the Hand
Palmar Aponeurosis strong triangular part of the deep fascia covers the soft tissues and overlies the long flexor tendons of the palm. Proximal end is continuous with the flexor retinaculum; Distal ends with the fibrous digital sheaths.
Flexor Pollicis Brevis muscle
Origin
: the transverse carpal ligament, trapezium bone
Insertion
: the base of the proximal phalanx of the thumb
Function
: flexes the proximal phalanx of the thumb
Nerve
: the muscular branches of the median, the deep branches of the ulnar
Artery
: the superficial volar branch of the radial
Abductor Pollicis Brevis muscle
Origin
: transverse carpal ligament, scaphoid and trapezium bones
Insertion
: radial side of the base of the proximal phalanx of the thumb
Function
: abducts the thumb, draws the thumb forward at right angles to the palm
Nerve
: Muscular branches of the median
Artery
: the superficial volar branch of the radial
Opponens Pollicis muscle
Origin
: the transverse carpal ligament, the trapezium bone
Insertion
: the anterior surface, radial side of the 1st metacarpal bone
Function
: draws the 1st metacarpal bone forward, and medially, opposing the thumb to each of the other digits.
Nerve
: the muscular branch of the median
Artery
: the superficial volar branch of the radial
Palmaris Brevis muscle
Origin
: the ulnar side of the transverse carpal ligament and the palmar aponeurosis
Insertion
: the skin on the ulnar border of the palm
Function
: corrugates the skin on the ulnar side of the palm and deepens the hollow of the hand
Nerve
: the superficial volar branch of the ulnar
Artery
: the superficial volar arch
Superficial Palmar Arch
formed mainly by the ulnar artery, this arch lies distal to the proximal transverse crease of thee palm at its middle convexity. The arch gives rise to 3 common palmer arteries that anastomose with the palmar metacarpal arteries from the deep palmer arch. The deep arch is closer to the wrist than the superficial palmar arch.
Deep Palmar Arch
this arch lies across the metacarpal bones just distal to their base.
Ulnar nerve (Superficial br)
supplies cutaneous fibers to the medial one and one half digits
Ulnar nerve (Deep br)
supplies motor fibers to the hypothenar, medial two lumbricals, adductor pollicis, and all the interosseus muscles. It also supplies several joints (wrist, intercarpal, carpometacarpal, and intermetacarpal)
Flexor Retinaculum
a thickening of deep fascia through which all flexors tendons travel. Attached medially to pisiform and hook of the hamate, laterally by the scaphoid and trapezium. Forms the carpal tunnel.
Carpal Tunnel
the space for the extensor tendons created laterally by the hook of the hamate, medially by the trapezium, dorsally by the palmar radiocarpal ligament, and ventrally (palmer) by the Flexor retinaculum.
Digital branches of Median nerve
supplies the thenar and 1st and 2ndlumbrical muscles, as well as sensory innervation for the lateral surface of the palm, the palmar surface of the thumb, and the lateral two and one half digits (including the nails).
Abductor Digiti Minimi muscle
Origin
: the pisiform bone and the tendon of the flexor carpi ulnaris
Insertion
: the medial side of the base of the proximal phalanx of the 5th digit and the aponeurosis of the extensor Digiti minimi.
Function
: abducts the 5th digit from the 4th digit
Nerve
: the deep volar branch of the ulnar
Artery
: the deep volar branch of the ulnar, the dorsal carpal branch of the ulnar
Digital branches of Ulnar nerve
supply the tip of the little finger.
Recurrent Branch of the Median nerve
innervates the thenar eminence
Flexor Digiti Minimi muscle
Origin
: the transverse carpal ligament and the hamulus of the hamate bone
Insertion
: the ulnar side of the base of the proximal phalanx of the 5th digit
Function
: flexes the proximal phalanx of the 5th digit
Nerve
: the deep volar branch of the ulnar
Artery
: the deep volar branch of the ulnar, the dorsal carpal branch of the ulnar
Opponens Digiti Minimi muscle
Origin
: the transverse carpal ligament, the hamulus of the hamate bone
Insertion
: the ulnar margin of the 5th metacarpal bone
Function
: draws the 5th metacarpal bone forward to face the thumb, deepens the hollow of the hand
Nerve
: the deep volar branch of the ulnar
Artery
: the deep volar branch of the ulnar, the dorsal carpal branch of the ulnar
Tendons of Flexor Digitorum Superficialis and Flexor Digitorum Profundus
the 4 tendons of the flexor digitorum superficialis travel through the carpal tunnel anterior to the 4 tendons of the flexor digitorum profundus.
Common Synovial Sheaths
surround the four tendons of the flexor digitorum superficialis as it goes through the carpal tunnel.
Digital Synovial Sheaths
sheaths surrounding the tendons of the flexor digitorum superficialis and profundus. Located on the anterior (palm) side of the phalanges.
Lumbricals
(4) muscles
Origin
: all arising from the tendons of the flexor digitorum profundus:
1st from the radial side of the tendon for the index finger
2nd from the radial side of the tendon for the middle finger
3rd from adjacent sides of the tendons for the middle and ring fingers
4th from adjacent sides of tendons for the ring and little fingers
Insertion
: with tendons of extensor digitorum and interossei into bases of terminal phalanges of the medial 4 digits
Function
: flex the fingers at the metacarpophalangeal joints, extend the fingers at the interphalageal joints
Nerve
: Median, to the lateral two muscles, deep volar branch of the ulnar to the medial two muscles
Arteries
: the superficial and deep volar arches
Extensor Expansions
are tendons over the dorsal portion of the distal phalanges.
Adductor Pollicis muscle
Origin
:
Oblique head
from the trapezium, trapezoid and capitate bones, the base of the 2nd and 3rd metacarpal bones,
Transverse head
from the volar surface of the 3rd metacarpal bone
Insertion
: the ulnar side of the base of the proximal phalanx of the thumb
Function
: adducts the thumb, aids in opposition
Nerve
: the deep volar branch of the ulnar
Artery
: the deep volar arch
Dorsal Interossei muscles (4)
Origin
each arise by 2 heads from adjacent sides of the metacarpal bones
Insertion
1st into the radial side of the proximal phalanx of the 2nd digit
2nd into the radial side of the proximal phalanx of the 3rd digit
3rd into the ulnar side of the proximal phalanx of the 3rd digit
4th in to the ulnar side of the proximal phalanx of the 4th digit
Function
abduct the index, middle, and ring fingers from the midline of the hand
Nerve
Deep volar branch of the ulnar
Artery
deep volar arch
Palmar Interossei muscles (3)
Origin
1st from the ulnar side of the 2nd metacarpal bone
2nd from the radial side of the 4th metacarpal bone
3rd from the radial side of the 5th metacarpal bone
Insertion
1st into the ulnar side of the proximal phalanx of the 2nd digit
2nd into the radial side of the proximal phalanx of the 4th digit
3rd in to the radial side of the proximal phalanx of the 5th digit
Function
each muscles adducts the digit into which it is inserted toward the middle digit
Nerve
Deep volar branch of the ulnar
Artery
Deep volar arch
Posterior Interosseous nerve a branch of the deep branch of the radial nerve, it accompanies the posterior interosseus artery and supplies the deep extensor muscles.
Dorsal Carpal Venous Arch the veins of the digits drain into 3 dorsal metacarpal veins, which unite to form a dorsal venous network visible through the skin of the back of the hand.
Extensor Expansion tendons over the dorsal portion of the phalanges
Structures Running Through the Wrist
The Thenar eminence (the mass of the proximal thumb), innervated by the Recurrent Branch of the Median, containsthe flexor pollicis brevis, abductor pollicis brevis, and opponens pollicis
The Hypothenar eminence is the mass on the "pinkie" side.
The Palmarus longus tendon is a "spare tendon" that can be used as a graft without resulting in a loss of function.
4th tunnel (2) extensor digitorum and extensor indicis
5th tunnel (1) extensor digiti minimi (hint: the 5th finger is the smallest
Þ "mini-me")
6th tunnel (1) extensor carpi ulnaris
the palmar aponeurosis causes the creases in the skin of the palm where it binds tightly underneath the skin
9 tendons through the carpal tunnel
4 flexor digitorum superficialis
4 flexor digitorum profundus
1 flexor palmarus longus
the median nerve also travels through the carpal tunnel
Synovial sheaths on these tendons protect them from friction. However when these tendons or their sheaths get inflamed, the median nerve in compressed
Joints
Shoulder
Glenoid Fossa the depression in the scapula where the humeral head articulates
Glenoid Labrum a fibrocartilaginous rim that deepens the glenoid fossa slightly.
Humeral Head the most proximal portion of the humerus; its rounded surface articulates at the glenoid fossa
Glenohumeral Ligaments are thickenings of the anterior part of the fibrous capsule which strengthen the shoulder joint. The three portions (superior, middle, and inferior glenohumeral ligaments) are frequently indistinct. They run from the supraglenoid tubercle of the scapula to the lesser tubercle and the anatomic neck of the humerus.
Elbow
Trochlea the hinge at the distal end of the humerus; where the ulna articulate
Capitulum the rounded articular surface on the lateral side of the distal humerus, where the radius articulates
Radial Head the proximal radius, where it articulates with the Capitulum of the humerus
Annular ligament holds the radial head to the Capitulum
Ulnar collateral ligament the ligament on the medial side of the elbow (4 parts; anterior, posterior, medial, and oblique)
Wrist
Lunate Surface articulates with the radius in the lunate fossa. Medial to where the scaphoid articulates
Scaphoid Surface articulates with the radius in the Scaphoid fossa; lateral to where the lunate articulates
Articular Disk the fibrocartilage at the distal end of the ulna which participates in the articulation with the carpal bones.
Radiocarpal ligaments ligaments on the dorsal and palmar side that attach to the distal radius and proximal carpal bones
Scaphoid the carpal bone located in the snuff box. Articulates with the radius
Lunate the proximal carpal bone that with the scaphoid, articulates with the radius
Triqetrium the proximal carpal bone medial to the lunate.