muscles of the hand

Question 1

Opponens Pollicis

Answer 1

the largest of the thenar muscles, and lies underneath the other two.

Origin Flexor retinaculum and tubercles of scaphoid and trapezium
Insertion Lateral side of 1st metacarpal
Action Draws 1st metacarpal laterally to oppose thumb toward center of palm
Innervation Recurrent branch of median nerve (C8 and T1)

Question 2

The abductor pollicis brevis

Answer 2

forms the anterolateral aspect of the thenar eminence,

Originates from the tubercles of the scaphoid and trapezium, and from the associated flexor retinaculum. Attaches to lateral side of proximal phalanx of the thumb.
Actions: Abducts the thumb.
Innervation: Median nerve (recurrent branch).

Question 3

The flexor pollicis brevis

Answer 3

Originates from the tubercle of the trapezium and from the associated flexor retinaculum.
Attaches to the base of the proximal phalanx of the thumb.
Actions: Flexes the metacarpophalangeal joint of the thumb.
Innervation: Median nerve (recurrent branch). The deep head is innervated by the deep branch of the ulnar nerve.

Question 4

Opponens Digiti Minimi

Answer 4

Originates from the hook of hamate and associated flexor retinaculum,
It inserts into the medial margin of metacarpal V.
Actions: It rotates the metacarpal of the little finger towards the palm, producing opposition.
Innervation: Ulnar nerve.

Question 5

Abductor Digiti Minimi

Answer 5

Origin Pisiform
Insertion Medial side of base of proximal phalanx of little finger
Action Abducts little (5th) finger
Innervation ulnar nerve (C8 and T1)

Question 6

Flexor Digiti Minimi Brevis

Answer 6

Origin Hook of hamate and flexor retinaculum
Insertion Medial side of base of proximal phalanx of little finger
Action Flexes proximal phalanx of little (5th) finger
Innervation ulnar nerve

Question 7

Lumbricals

Answer 7

Each lumbrical originates from a tendon of the flexor digitorum profundus. They pass dorsally and laterally around each finger
inserts into the extensor hood.There are four lumbricals in the hand, each associated with a finger.
Actions: Flexion at the MCP joint and extension at the interphalangeal (IP) joints of each digit.
Innervation: The lateral two lumbricals (of the index and middle fingers) are innervated by the median nerve. The medial two lumbricals (of the little and ring fingers) are innervated by the ulnar nerve.

(Denervation of these muscles is the basis for the ulnar claw and hand of benediction.)

Question 8

dorsal interossei muscles.

Answer 8

There are four dorsal interossei muscles.

Each interossei originates from the lateral and medial surfaces of the metacarpals.
They attach into the extensor hood and proximal phalanx of each finger.
Actions: Abduction of the digits. Assists in flexion at the metacarpophalangeal joints and extension at the interphalangeal joints.
Innervation: Ulnar nerve.

Question 9

Palmar Interossei

Answer 9

These are located anteriorly on the hand.

Each interossei originates from a medial or lateral surface of a metacarpal,
It attaches into the extensor hood and proximal phalanx of same finger.
Actions: Adduction of the digits. Assists in flexion at the metacarpophalangeal joints and extension at the interphalangeal joints.
Innervation: Ulnar nerve.

Question 10

The palmaris brevis

Answer 10

is a small, thin muscle, found superficially in the subcutaneous tissue of the hypothenar eminence.

Attachments: Originates from the palmar aponeurosis and flexor retinaculum, attaches to the dermis of the skin on the medial margin of the hand.
Actions: Wrinkles the skin of the hypothenar eminence and deepens the curvature of the hand, improving grip.
Innervation: Ulnar nerve.

Question 11

Adductor Pollicis

Answer 11

The adductor pollicis large triangular muscle with two heads. The radial artery passes anteriorly through the space between the two heads, forming the deep palmar arch.

Origin: 2nd and 3rd metacarpals, capitate,
Insertion: Medial side of base of proximal phalanx of thumb
Action Adducts thumb
Innervation ulnar nerve

Question 12

thenar eminence

Answer 12

is the body of muscle on the palm of the human hand just beneath the thumb.
Abductor pollicis brevis, Flexor pollicis brevis, Opponens pollicis, Adductor pollicis
“OA2F”

Question 13

hypothenar eminence

Answer 13

is the body of muscle on the palm of the human hand just beneath the 5th phalange
Abductor digiti minimi & Flexor digiti minimi Opponens digiti minimi
“OAF”

Question 14

how does the median nerve innervates

Answer 14

The median nerve innervates the palmer side of your 1st, 2nd,3rd, and medial 4th fingers.
The Median nerve is involved with carpal tunnel syndrome

Question 15

how does the ulnar nerve innervates

Answer 15

The Ulnar nerve supplies feeling and motor function to the lateral 4th and 5th fingers.

Question 16

how does the radial nerve innervates

Answer 16

The radial nerve innervates most of the extensors and supplies the feeling on the dorsal side of the first three digits

Question 17

what kind of joints are metacarpophalangeal (knuckle)

Answer 17

Condyloid: egg-shape articular surface + oval concavity
side-to-side, back+forth movement

Question 18

what kind of joints are carpometacarpal joint (Thumb)

Answer 18

Saddle: articular surface both concave + convex
side-to-side, back-forth movement

Question 19

What kind of joints are found between phalanges

Answer 19

In between the Phalanges are Hinge Joints
They move in flexion and extension

Question 20

An Injury to a Ligament is called

Answer 20

(A Ligament attaches a bone to bone_)
a Sprain

Question 21

An injury to a tendon or Muscle is

Answer 21

(A Tendon Attaches a muscle to a bone)
a strain

Question 22

Collateral ligaments

Answer 22

are found on either side of each finger and thumb joint. The function of the collateral ligaments is to prevent abnormal sideways bending of each joint.

Question 23

ulnar collateral ligament

Answer 23

is a rounded cord,
attached above to the end of the styloid process of the ulna, and dividing below into two
one of which is attached to the medial side of the triquetrium and pisiform

Question 24

The radial collateral carpal ligament

Answer 24

attaches to the styloid process of the radius and the radial side of the scaphoid bone.

Question 25

transverse carpal ligament

Answer 25

AKA The flexor retinaculum

a strong, fibrous band, converting the deep groove on the front of the carpal bones into a tunnel, the carpal tunnel, through which the Flexor tendons of the digits and the median nerve pass.