Muscles Of The Hand Flashcards
Thenar muscles (3)
Flexor Pollicis Brevis
Abductor Pollicis Brevis
Opponens Pollicis
OINA for Adductor Pollicis Brevis
OR: Scaphoid bone
Trapezium
INS: Base of proximal phalanx, digit 1 (lateral side)
NS: Recurrent branch of median nerve
AC: Abducts thumb at CMC and MCP
OINA for Flexor Pollicis Brevis
OR: Superficial head from flexor retinaculum and trapezium
Deep head- floor of the carpal tunnel (over trapezoid and capitate)
INS: Base of Proximal phalanx, digit 1 (lateral side)
NS: Recurrent branch of medial nerve (superficial head)
Deep branch of ulnar (deep head)
AC: Flexes digit 1 at MCP
OINA for Opponens Pollicis
OR: Trapezium
INS: Lateral side of 1st metacarpal
NS: Recurrent branch of median nerve
AC: Opposes digit 1
Pulls and medially rotates 1st metacarpal across the palm
Hypothenar muscles (3)
Flexor digiti minimi brevis
Abductor digiti minimi
Opponens digiti minimi
OINS for Abductor digiti minimi
OR: Pisiform
INS: Proximal phalanx of digit 5 (medial side)
NS: Deep branch of ulnar nerve
AC: Abduct digit 5
OINA for Frlexor Digigi Minimi Brevis
OR: Hook of hamate
INS: Proximal phalanx of digit 5
NS: Deep branch of ulnar nerve
AC: Flexes digit 5 at MCP
What muscle is not normally found in humans?
Flexor digiti minimi longus
OINA for Opponens Digiti Minimi
OR: Hook of hamate
INS: body of 5th metacarpal (palmar surface)
NS: Deep branch of ulnar nerve
AC: Opposes digit 5 (abducts, flexes and laterally rotates the 5th metacarpal, cupping the hand)
Central compartment muscles (8)
Abductor pollicis brevis
Flexor pollicis brevis
Oblique head of adductor pollicis
Transverse head of adductor pollicis
Flexor digiti minimi
Abductor digiti minimi
Superficial palmar arch
Common palmar digital branches
OINA Lumbricals 1 & 2
OR: Lateral 2 tendons of flexor digitorum profundus
INS: Attach to the lateral sides of the extensor expansion of digits 2 & 3
NS: Lateral 2 (digits 2 and 3)= median nerve
AC: Flexes MCP joints
Extends IP joints
OINA for Lumbricals 3 &E 4
OR: Medial 3 tendons of flexor digitorum profundus
INS: Lateral sides of the extensor expansion of digits 4 & 5
NS: Medial 2 (digits 4 & 5) = deep branch of ulnar nerve
Action: Flexes MCP joints
Extends the IP joints
OINA for Adductor Pollicis
OR: Oblique Head : Metacarpal 2 and 3, and capitate
Transverse head: metacarpal 3
INS: Sesamoid bone on medial side of MCP
Proximal phalanx of digit 1
NS: Deep branch of ulnar nerve
AC: Adduct digit 1
What muscle is innervated completely by the ulnar nerve?
Thenar muscle
OINA for Dorsal Interosseous
OR: Adjacent 2 metacarpals (all for are bipennate)
INS: Proximal Phalanx
Extensor expansion
NS: Deep branch of the ulnar nerve
AC: Abducts digits away from digit 3
Adductor compartment muscle
Adductor pollicis
What muscles fill the space between the metacarpal bones?
Dorsal interosseous muscles
Dorsal interosseous muscles are easily monitored indicators of:
Muscle wasting
What digits last the dorsal interosseous muscles? Why?
1st and 5th digits because they have their own abductors
Remember:
DAB =
PAD =
DAB = Dorsal interosseous ABducts
PAD = Palmar interosseous ADDucts
OINA for Palmar interosseous muscles
OR: Arise from palmar surface of metacarpals 2, 4 and 5
INS: Extensor expansion at bases of proximal phalanges of digits 2, 4, & 5
NS: Deep branch of ulnar nerve
AC: Adducts digits towards digit 3
Interosseous of the 1st metacarpal
Flexor Pollicis Brevis
Extensor expansion, AKA
Dorsal expansion
Or
Dorsal hood
Anatomical term that refers to the special connective attachments by which the extensor tendons insert into the phalanges
Extensor Expansion
The aponeurosis of extensor muscles span:
The proximal and middle phalanges
What happens to the extensor tendon at the distal end of the metacarpal?
It will expand to form a hood, which covers the back and sides of the head of the metacarpal and the proximal phalanx
What muscles insert on the extensor expansion?
What do these serve to extend?
The Lumbricals, extensor indicis, dorsal interossei, and palmar interossei
These serve to extend the interphalangeal joints
What muscles flex the metacarpal phalanges joints?
The interossei and Lumbricals
