Hand Bones and Flexor Retinaculum

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Questions and Answers

Which of the following muscles is NOT part of the Thenar Eminence?

Flexor pollicis brevis

Opponens pollicis

Abductor pollicis brevis

Adductor pollicis (correct)

Which nerve is responsible for supplying the muscles of the Thenar Eminence?

Ulnar nerve

Median nerve (correct)

Radial nerve

Palmar cutaneous branch of the median nerve

Which of the following structures does NOT pass deep to the Flexor Retinaculum?

Median nerve

Flexor carpi radialis tendon

Flexor digitorum profundus tendons

Palmaris longus tendon (correct)

Which of the following bones is NOT part of the Distal row of the carpal bones?

Pisiform Signup and view all the answers

Which of the following muscles is NOT part of the Hypothenar Eminence?

Adductor pollicis Signup and view all the answers

What are the two vessels that arise from the radial artery in the plane between the first dorsal interosseous and adductor pollicis?

Princeps pollicis artery and radialis indicis artery Signup and view all the answers

Which of the following nerves does not innervate any intrinsic muscles of the hand?

Radial nerve Signup and view all the answers

What is the origin of the Cephalic vein?

Lateral side of the dorsal venous network Signup and view all the answers

What is the function of the Extensor Retinaculum?

To provide a strong, fibrous band that extends obliquely across the back of the wrist Signup and view all the answers

Which arteries arise from the dorsal carpal arch?

Dorsal metacarpal arteries Signup and view all the answers

Which muscle is responsible for adduction of the thumb?

Adductor Pollicis Signup and view all the answers

What is the main action of the Lumbrical Muscles?

Flexion of the Metacarpophalangeal joint and extension of the Interphalangeal joint Signup and view all the answers

Which artery is responsible for supplying the thumb and lateral side of the index finger?

Radial artery Signup and view all the answers

Which nerve supplies the medial two lumbrical muscles?

Deep branch of the ulnar nerve Signup and view all the answers

What is the name of the vascular arch formed by the radial artery on the lateral side of the palm?

Deep Palmar Arch Signup and view all the answers

Study Notes

Hand Anatomy

Carpal bones can be remembered using the mnemonic "She Looks Too Proud, Try To Chase Her"
Proximal row of carpal bones: Scaphoid, Lunate, Triquetrum, Pisiform
Distal row of carpal bones: Trapezium, Trapezoid, Capitate, Hamate

Flexor Retinaculum

A thickening of deep fascia that holds long flexor tendons in position at the wrist
Attaches medially to the pisiform bone and the hook of the hamate, and laterally to the tubercle of the scaphoid and the trapezium bones

Structures Passing Deep to Flexor Retinaculum

Flexor digitorum superficialis tendons
Median nerve
Flexor pollicis longus tendon
Flexor carpi radialis tendon

Structures Passing Superficial to Flexor Retinaculum

Flexor carpi ulnaris tendon
Ulnar nerve
Ulnar artery
Palmar cutaneous branch of the ulnar nerve
Palmaris longus tendon
Palmar cutaneous branch of the median nerve

Carpal Tunnel

A fibro-osseous canal formed by the carpal bones and the flexor retinaculum
Contents: tendons of FDS, FDP, and FPL, and the median nerve

Muscles of the Hand

Divided into two groups: extrinsic and intrinsic
Extrinsic group: muscles that originate outside the hand and insert into the hand bones
Intrinsic group: arranged in five parts - thenar eminence, hypothenar eminence, adductor pollicis, interosseous muscles, and lumbrical muscles

Thenar Eminence

Three muscles responsible for the prominent swelling on the lateral side of the palm at the base of the thumb
Opponens pollicis, flexor pollicis brevis, and abductor pollicis brevis
All supplied by the recurrent branch of the median nerve

Hypothenar Eminence

Three muscles responsible for the swelling at the base of the little finger
Branches: three palmar metacarpal arteries and three perforating branches

Dorsal Carpal Arch

Formed by the radial artery before penetrating the back of the hand
Gives rise to the dorsal carpal branch, which passes medially as the dorsal carpal arch, and subsequently divides to become small dorsal digital arteries

Veins of the Hand

Deep veins follow the arteries
Superficial veins drain into a dorsal venous network on the back of the hand over the metacarpal bones
The Cephalic vein originates from the lateral side of the dorsal venous network and passes over the anatomical snuffbox into the forearm
The Basilic vein originates from the medial side of the dorsal venous network and passes into the dorso-medial aspect of the forearm

Nerves of the Hand

The hand is supplied by the ulnar, median, and radial nerves
The ulnar nerve innervates all intrinsic muscles of the hand except for the three thenar muscles and the two lateral lumbricals, which are innervated by the median nerve
The radial nerve only innervates skin on the dorsolateral side of the hand

Extensor Retinaculum

A strong, fibrous band that extends obliquely across the back of the wrist
Attached laterally to the anterior border of the radius, and medially to the triquetral and pisiform bones

Adductor Pollicis

Originates as two heads: transverse head from the anterior aspect of the shaft of the 3rd metacarpal, and oblique head from the capitate and adjacent bases of the 2nd and 3rd metacarpals
Inserts into the medial side of the base of the proximal phalanx of the thumb
Supplied by the deep branch of the ulnar nerve
Action: adduction of the thumb

Interosseous Muscles

Divided into two groups: dorsal interossei and palmar interossei
All are supplied by the deep branch of the ulnar nerve
Action: PAD (palmar abduction of the fingers), DAB (dorsal abduction of the fingers)

Lumbrical Muscles

Four worm-like muscles, each associated with one of the fingers
Originate from the tendons of FDP in the palm
The medial two lumbricals are innervated by the deep branch of the ulnar nerve; the lateral two lumbricals are innervated by digital branches of the median nerve
Action: flex MPJ (metacarpophalangeal joint) and extend IPJ (interphalangeal joint)

Blood Vessels of the Hand

Blood supply to the hand is by the radial and ulnar arteries
These arteries form two interconnected vascular arches (superficial and deep) in the palm
The radial artery contributes substantially to the supply of the thumb and the lateral side of the index finger
The remaining digits and the medial side of the index finger are supplied mainly by the ulnar artery

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Description

Learn about the bones in the hand, including carpal bones and their mnemonics, as well as the flexor retinaculum and its attachment points. Identify the proximal and distal rows of carpal bones.