Week 2 Anatomy of the hand

Question 1

List the 8 carpals of the hand.

Answer 1

1. Scaphoid, lunate, triquetrum, pisiform (so long to pinky)

2. Hamate, Capitate, Trapezoid, Trapezium (Here comes the thumb)

Question 2

What are the components of the carpal tunnel?

Answer 2

• Median Nerve
• tenon of flexor pollicis longus
• tendons of flexor digitorum superficialis (4)
• tendons of flexor digitorum profundus (4)

Question 3

What happens in carpal tunnel syndrome?

Answer 3

• clinical syndromes: tingling, loss of sensation in radial 3 1/2 digits, progressive loss of coordination and strength of thenar muscles, reduce capability to oppose thumb
• due to damage to median nerve

Question 4

Describe the anatomical movements of the thumb around its two joints.

Answer 4

Carpometacarpal of the thumb - abduction, adduction, extension, flexion and rotation (for opposition and reposition). Between the trapezium and first metacarpal (Mc1).

Interphalangeal (IP) of the thumb – flexion and extension only. Between the proximal and distal pollical phalanges.

Question 5

Describe the anatomical mvts of the digits 2-5 around their joints.

Answer 5

1. Radiocarpal and Midcarpal – flexion, extension, abduction and adduction; midcarpal joints have more mobility than carpometacarpal joints.
2. Carpometacarpal of the digits 2-5 - variable amount of flexion, extension, abduction, and adduction; more movement at the ulnar side (Mc5) and less at the radial side (Mc2 and Mc3)
3. Metacarpophalangeal (MP) - flexion and extension; limited abduction and adduction when making a fist.
4. Proximal- and Distal-Interphalangeal (PIP and DIP) of digits 2-5 – flexion and extension

Question 6

List the thenar muscles and their innervation.

Answer 6

1. flexor pollicis brevis
2. abductor pollicis brevis
3. opponens pollicis
   Innervated by recurrent branch of the median nerve

Question 7

Llist the hypothenar muscles and their innervation.

Answer 7

1. flexor digiti minimi
2. abductor digiti minimi
3. opponens digiti minimi
   Innervated by the Ulnar Nerve

Question 8

Describe the innervation of the lumbricals and where they insert. What is their action?

Answer 8

-Inserts radially
-originate on tendons of flexor digitorum profundus and inserts on extensor expansions distal to MP joints
Innervation
-medial 2 lumbricals: ulnar nerve
-lateral 2 lumbricals: Median nerve
Action:
-extensor of DIP and PIP, flexor of MCP

Question 9

Describe the interosseous muscles. Action and innervation.

Answer 9

1. Dorsal interossei (x4)
   -aBductor of digits, flexor of MCP, extensor of IP joints
   -inserts radially on digits 2+3, inserts ulnar side on 3+4
2. Palmar interossei (x3)
   -inserts ulnar side on digit 2, radially on 4+5
   -ADductor of digits, flexor of MP joints, extensor of IP joints
   All innervated by ULNAR nerve

Question 10

What is the adductor pollicis innervated by?

Answer 10

Ulnar nerve. It’s an intrinsic hand muscle.