Carpal Tunnel

Question 1

What is the carpal tunnel?

Answer 1

Narrow passageway found on anterior portion of wrist. Serves as entrance to the palm for tendons and the median nerve

Question 2

Borders of carpal tunnel

Answer 2

Formed by two layers: deep carpal arch and superficial flexor retinaculum

Question 3

Deep carpal arch forms a

Answer 3

Concave surface, converted into a tunnel by overlying flexor retinaculum (transverse carpal ligament)

Question 4

Carpal arch

Answer 4

Concave on palmar side, forming base and sides of carpal tunnel
Formed laterally by scaphoid and trapezium tubercles
Formed medially by hook of hamate and pisiform

Question 5

Flexor retinaculum

Answer 5

Thick connective tissue forming roof of carpal tunnel
Turns carpal arch into carpal tunnel by bridging space between medial and lateral parts of the arch
Spans between hook of hamate and pisiform (medially) to the scaphoid and trapezium (laterally)

Question 6

Contents of carpal tunnel

Answer 6

9 tendons surrounded by synovial sheaths and median nerve

Question 7

Palmar cutaneous branch

Answer 7

Palmar cutaneous branch of median nerve given off prior to carpal tunnel, travelling superficially to flexor retinaculum

Question 8

Tendons of carpal tunnel

Answer 8

Tendon of flexor pollicis longus
4 tendons of flexor digitorum profundus
4 tendons of flexor digitorum superficialis

Question 9

Synovial sheaths

Answer 9

4 Flexor digitorum profundus and 4 flexor digitorum superifcialis surrounded by same synovial sheath
Flexor pollicis longus surrounded by own synovial sheath
Allow free move,ent of tendons

Question 10

Where is the flexor carpi radialis tendon?

Answer 10

Within flexor retinaculum, not carpal tunnel itself

Question 11

Median nerve

Answer 11

Once it passes through carpal tunnel, median nerve divides into 2 branches (recurrent branch and palmar digital nerves)

Question 12

Palmar digital nerves

Answer 12

Give sensory innervation to palmar skin and dorsal nail beds of lateral three and a half digits
Provide motor innervation to lateral two lumbricals

Question 13

Recurrent branch

Answer 13

Supplies thenar muscle group

Question 14

Carpal tunnel syndrome

Answer 14

Compression of median nerve within carpal tunnel
Caused by thickened ligaments and tendon sheaths
Weakness and atrophy of thenar muscles
Numbness, tingling, pain, radiating to forearm