The Hand

Question 1

Palmaris Brevis

• Attachments
• Function
• Innervation

Answer 1

• Palmar aponeurosis and flexor retinaculum to dermis
• Grip
• Ulnar nerve (Superficial C8+T1)

Question 2

Intrinsic Muscles - Thenar Eminence

• Abductor pollicis brevis attachments, function, innervation
• Flexor pollicis attachments, function, innervation
• Opponens pollicis attachments, function, innervation

Answer 2

• scaphoid and trapezium to base proximal phalanx of thumb – CMC joint abduction – median nerve (recurrent C8,T1)
• flexor retinaculum, capitate, trapezium to base proximal phalanx of thumb – CMC joint flexion – Median (recurrent) and some texts also ulnar nerve (C8,T1)
• trapezium to first metacarpal – CMC joint opposition – median nerve (recurrent C8,T1)

Question 3

Adductor Pollicis

• Attachments
• Function
• Innervation

Answer 3

• Transverse head from 3rd metacarpal, oblique head from capitate and 2nd/3rd metacarpals to base of proximal phalanx of thumb
• Adduction of CMC joint of thumb and flexion of MCP joint of thumb
• Ulnar nerve (deep C8+T1)

Question 4

Hypothenar Eminence

• Abductor digiti minimi (attachments, function, nerves)
• Flexor digiti minimi (attachments, function, nerves)
• Opponens digiti minimi (attachments, function, nerves)

Answer 4

• pisiform bone to base of 5th proximal phalanx and dorsal digital expansion – abduction and flexion MCP joint little finger – ulnar nerve (deep C8,T1)
• hamate, flexor retinaculum to base of 5th proximal phalanx – Flex MCP joint of little finger – ulnar nerve (deep C8,T1)
• hamate and flexor retinaculum to 5th metacarpal – weak opposition of little finger – ulnar nerve (deep C8,T1)

Question 5

Lumbricals

• What are they?
• Unipennate and bipennate
• Function
• Innervation

Answer 5

• 4 small muscles from the tendons of the flexor digitorum profundus
• 1st goes to index and 2nd goes to middle. These are the unipennate ones. 3rd goes to ring finger and 4th goes to little. These are bipennate. Unipennate goes to one side of the tendon and bipennate goes to both sides.
• MCP joint flexion and IP joint extension for digits 2-4
• 1st and 2nd: medial nerve (digital C8+T1). 3rd and 4th: ulnar nerve (deep C8+T1)

Question 6

Palmer inteossei

• PAD and DAB
• Middle finger
• Thumb
• Innervation

Answer 6

• Palmar = Adduct and Dorsal = Abduct
• Centre of movement for adduction and abduction so no interossei
• Thumb has it’s own adductor so doesn’t need one either
• Ulnar nerve (deep C8+T1)

Question 7

Dorsal Interossei

• Function
• Thumb
• Middle finger
• Little finger
• Innervation

Answer 7

• Abduction (MCP flextion and IP extension)
• Doesn’t require dorsal interossei
• Has 2 dorsal interossei
• Doesn’t have one as it has it’s own abductor already
• Ulnar nerve (deep C8+T1)

Question 8

Palmar Arches

• Radial and ulnar arteries
• Superficial arch
• Deep arch
• Digital branches

Answer 8

• Anastomose to supply the hand
• Mostly ulnar
• Mostly radial
• To fingers up the lateral surfaces to avoid crushing when hand is flexed

Question 9

Synovial Sheaths

• What do they consist of?
• Where are they found?

Answer 9

• Synovial membrane and fluid
• Around tendons at wrist, palm and into digits

Question 10

Upper Limb Dermatomes

Answer 10