Muscles And Bones Of The Hand Flashcards
What carpal bones are in contact with the radius?
Scaphoid and lunnate bone.
What are the types of hand muscles?
Extrinsic hand muscles which originate in the forearm.
Intrinsic hand muscles which are containing within the carpal bone region.
What are the muscles of the thenar eminence?
OAF=
Oppones pollucis.
ABductor pollucis brevis
Flexor pollucis brevis
->Innervated by the median nerve
What is the hypothenar eminence?
AFO=
ABductor digiti minimi
Flexor digiti minimi
Oppones digit minimi
What are the lumbricles?
“Worms” which originate from the tendon of the flexor digitorum profundus. First 2 lumbricles are unipennate, and the remaining are bipennate. They attach to the extensor hood of the finger with common insertion with the extensor digitorum.
Role is to flex the MCP joint and extend ICP joint.
What is the flexor retinaculum?
Flat sheet of fibrous connective tissue which forms the roof of the carpal tunnel. The muscles which originate from here are the thenar and hypothenar eminence.
What is the palmar aponeurosis?
Fascia of the palm that is continuous with the flexor retinaculum. Has attachments for the palmaris longus and palmaris quadrate.
What is the abductor pollucis brevis?
Originates from the flexor retinaculum which attaches to the proximal phalanges, innervated by median nerve.
What is the flexor pollucis brevis?
Superficialis head: flexor retinaculum
Deep head: Trapezius and caphate bone
The superficial and deep head join at the sesamoid bone which attaches to the proximal phalange.
Innervated by the median nerve
What are the oppones pollucis?
Deepest muscle of the thenar muscle from the flexor retinaculum and the trapezium crest to lateral metacarpal bone of thumb.
Innervated by the median nerve.
What is the flexor pollucis longus?
Deep anterior forearm muscle that runs between the superficial and deep head of the abductor pollucis brevis.
What is the abductor digiti minimi?
From pisiform bone to the proximal phalanges 5.
What is the flexor digiti minimi brevis?
Originates from the hannate bone to the base of metacarpal 5.
What is the oppones digiti minimi?
From flexor retinaculum and hannate bone to the midshaft of metacarpal 5.
What is the palmaris brevis?
Square shaped muscle from flexor retinaculum and palmar aponeurosis to ulnar side of skin.
What is palmar interosseus muscle?
From the metacarpals to proximal phalanges for adduction towards midline of digits 2, 4 and 5, innervated by the ulnar nerve. There are 3 in total.
Thumb has a separate adductor muscle for adductor pollucis brevis and adductor pollucis longus.
What is the distal interosseus muscle?
Originates from the 2 metacarpals of the proximal phalange. It is important for abduction of digit 2,3 and 4.
Digit 1 and digit 5 have abductors in the thenar and hypothenar eminences.
What is the innervation to the muscles of the hand?
Mainly supplied by the ulnar nerve.
What is the alternative innervation to the hand?
Median nerve supplies:
Thenar eminence (opponus pollucis, abductor pollucis brevis and flexor pollucis brevis)
Superficial head of flexor pollucis brevis
Radial side of flexor digitorum profundus
Radial Lumbricles of digit 1 and 2
What are the features of the radial lumbricles?
Insert into the extensor hood and is innervated from the medial nerve for MCP flexion and ICP extension.
What is the function of the lumbricles?
Flexion of metacarpoppharyngeal joints and keeps extension of interpharyngeal joint.
Fine precision movements
Which intrinsic muscle of the thumb is innervated by the ulnar nerve?
Adductor pollucis
Which nerve innervated abduction?
Median nerve
Which nerve innervated adduction?
Ulnar nerve
Which nerve innervates the movement of flexion and extension?
Mixed nerve
What is the effect of median nerve lesion?
Sensory loss to the majority of the palm excluding half of digit 4 and digit 5
Dorsum of tips of fingers 2 and 3
Finger of Benediction where thumb, digit 2 and 3 remain extended.
What is the effect of ulnar nerve lesion?
Loss of sensation to digit 4 and 5
Loss of motor to majority of hand muscles, resulting in claw hand.
What is the effect of a radial nerve lesion?
Weak wrist extension so there is wrist drop
Sensory loss of web between thumb and index
What is the carpal tunnel?
Space beteeen carpal tunnel and flexor retinaculum. Allows the median nerve and the tendons of flexor digitorum superficialis and flexor digitorum profundus and flexor pollucis longus to pass through.
What is the anatomical snuff box?
Region in the dorsal aspect of the hand bordered by the TENDONS of the
ABductor pollucis longus, extensor pollucis longus and extensor pollucis brevis. It contains the trapezoid and scaphoid bone, radial artery and superficial radial nerve.
Which muscle is responsible for extension of MCP joint?
Extensor digitorum.
Which muscle is responsible for flexion of MCP joint?
Flexor digitorum and lumbricles
Which muscle is responsible for extension of IP joint?
Lumbricles.
How does the ulnar nerve enter the hand?
Guyon’s canal, a connective tissue sheath on the pisiform bone.
What is the adductor pollucis?
Has a:
->transverse head which arises from the base of metacarpals 2 and 3
->oblique head which arises from the 3rd metacarpal to attach to the proximal phalange of thumb.
Important for thumb adduction innervated by median nerve.
Which lumbricles are innervated by ulnar nerve?
Digits 3 and 4.
What is the blood supply of the deep palmar branch?
Formed by the radial artery to supply blood to the thumb and index finger.
What is the blood supply of the superficial palmar branch?
Formed by the ulnar artery to splurge blood to the deeper structures of the hand. Gives rise to the common digital arteries and proper digital arteries
