Week 6 Anatomy

Surface anatomy of the flexor retinaculum:
Attachements and structures pass under / over / through it.

Distal wrist crease – proximal border of flexor retinaculum

Medially – pisiform and hook of hammate

Laterally – scaphoid and trapezium

Carpal tunnel

9 tendons and one nerve

8 tendons share a sheath – FDP, FDS

Median nerve (lateral)

Flexor pollicis longus (most lateral)


FCR is not under carpal tunnel but is under flexor retinaculum.
Palmaris Longus blends on top
Ulnar artery and nerve pass above



Arterial supply of the hand.

Ulnar artery

Superficial palmar arch – mainly ulna

3 common palmar digital arteries anastamose with palmar metacarpal arteries

Each divide into pair of palmar digital arteries.

Deep palmar arch

Palmar metacarpal arteries.


Radial artery

Curves behind snuffbox and enters hand passing between the two heads of 1st dorsal interosseous muscles then between two heads of adductor pollicis.

End with anastamosis with deep palmar arch – mainly radial. (over metacarpal)

Princip pollicis artery

Palmar metacarpal arteries


Innervation of the muscles of the hand.

Median – LOAF

Lateral 2 lumbricals

Opponens pollicis

Abductor pollicis brevis

Flexor pollicis brevis


Ulnar – all other intrinsic muscles of hand

Medial 2 lumbricals


Hypothenar – abductor digiti minimi, flexor digiti minimi brevis, opponens digiti minimi

Adductor pollicis

Deep head of flexor pollicis brevis


Radial – from forearm.

Extensor pollicis longus, brevis, abductor pollicis longus



Sensory innervation of the hand.

Radial – 1st dorsal webspace, lateral 3.5 fingers’ dorsally up to DIP joints

Medial – lateral  3.5 fingers’ on palmar side and dorsally up to DIP joint

Ulna – medial 1.5 fingers palmar and dorsal surface

Median passes under two heads of pronator teres

Ulnar passes under the 2 heads of flexor carpi ulnaris




Actions of the interossei and the lumbricals.

PAD (Palmer Interossei Aduction)

DAB (Dorsal Interossei Abduction)




Wrist joint.

Proximal wrist crease

Condyloid/ellipsoid Synovial joint between distal radius and scaphoid, lunate and triquetrum (with articular disc of distal radioulnar joint)

Radial and ulnar collateral ligaments, palmar and dorsal radiocarpal ligaments

Flexion/extension, radial and ulna deviation, and circumduction

Innervated by radial, Ulna and median nerves




Blood supply of the scaphoid.

End arterial supply from distal branches of radial artery

Flows distal to proximal




Movements of the thumb

Saddle synovial joint

Trapezium and 1st metacarpal – separate articular cavity

Angular movements in any plane – flexion/extension, abduction/adduction, circumduction, restricted axial rotation

All three nerves

Arterial supply from anastamosis of wrist and hand





PIP and DIP – Hinge synovial joints

Flexion, extension

MCP – condyloid synovial joint

Flexion/extension, abduction/adduction

Deep transverse metacarpal ligaments hold the heads of medial 4 metacarpal heads together.

Supplied by digital arteries.

Hand compartments

 Palmar aponeurosis (deep fascia)

Fibrous digital sheaths

Medial fibrous septum – from palmar aponeurosis to 5th metacarpal

Medial to this is the hypothenar compartment

Lateral fibrous septum – from palmar aponeurosis to 3rd metacarpal

Lateral to this is the thenar compartment

Between the two septum – central compartment – flexor tendons, sheaths, lumbricals, superficial palmar arch, digital vessels and nerves.

Mid palmar space is cont to ant compt of forearm via carpal tunnel


Intrinsic hand muscles


Flexor pollicis brevis

Superficial and deep part

Origin – distal flexor retinaculum and trapezium tubercle

Insertion – base of proximal phalynx

Innervation – median nerve

Deep part = First palmar interossei – origin – ulnar side of first metacarpal, inserts – ulnar side of base of proximal phalynx. Ulnar innervarion

Abductor pollicis brevis

Contributes to bulk of thenar eminence, middle

Origin – distal flexor retinaculum and scaphoid tubercle, sometimes trapezium tubercle

Inserts – radial side of base of first phalynx and capsule of MCP.

Median nerve

Opponens Pollicis

Deep to the above two, most medial

Origin – distal flexor retinaculum and trapezium tubercle

Inserts – length of thumb metacarpal on radial side.

Median nerve

Blood – superficial palmar arch




Opponens digiti minimi – deep

Abductor digiti minimi – most superficial, origin pisiform/FCU

Flexor digiti minimi brevis – medial



Non thenar

Adductor pollicis

Transverse and oblique head. Deep to the others

Origin transverse head – ant body of 3rd metacarpal

Origin oblique head – base of 2nd and 3rd metacarpals and capitate and trapezoid.

Common insertion – ulnar side of base of proximal phalynx of thumb.

Ulnar nerve

Blood – deep palmar arch between the two heads from radial artery


Lumbricals 4

Arise from FDP tendons–> dorsal hood

1&2 unipentate, 3&4 bipentate.


4 dorsal and 3 palmar. Dorsal are bipentate, palmar are unipentate.