Anatomy 11/14

List the bones of the hand from proximal to distal

Answer explanation

Metacarpals —> proximal phalange/phalanx —> middle phalange/phalanx (not in the thumb) —> distal phalange/phalanx

List the 3 joints in the hand and the type of joint that they each are

Answer explanation

Carpometacarpal Joints – plane type of synovial joint (thumb is a saddle type of synovial joint)  

THUMB: Flexion, extension, abduction, adduction, opposition, reposition  

Metacarpaophalangeal Joints – condyloid type of synovial joint  

Flexion, extension, abduction, adduction, circumduction  

THUMB: only flexion and extension  

Interphalangeal Joints (PIP and DIP)  – hinge type of synovial joint  

Flexion & extension  

Which structure forms the “fibro-osseous tunnel” designed to prevent bowstringing of tendons?   

• Synovial sheath – flexor tendons

• Extensor expansion  

• Fibrous sheath – flexor tendons  

• Palmar aponeurosis  

Answer explanation

Synovial sheath – flexor tendons  

*Radial bursa, common flexor sheath, digital sheath 

Extensor expansion  

*Insertion for extensor tendons  

Fibrous sheath – flexor

tendons  

*Enclose flexor tendons in their synovial sheaths, pulleys  

Palmar aponeurosis  

*Thickening in the palm for Palmaris longus insertion  

Name the four thenar muscles of the hand: 

Answer explanation

Opponens pollicis 

Abductor pollicis brevis 

Flexor pollicis brevis 

Adductor pollicis  

What is the only muscle of the thenar muscles that is innervated only by the deep branch of the ulnar nerve (DBUN)? 

Answer explanation

Adductor pollicis 

*Flexor pollicis brevis is innervated by both RBMN and DBUN

Multiple choise: All of the thenar muscles insert onto the proximal phalanx of the thumb except: 

• Opponens Pollicis: Inserts onto the lateral side of the first metacarpal 

• Abductor pollicis brevis

• Flexor pollicis brevis 

• Adductor pollicis 

What are the main actions of the Lumbrical muscles? 

Answer explanation

Flexion of MP joints, extension of IP joints 

True or false: An intrinsic plus hand is caused by imbalances between strong extrinsic (or short) and weak intrinsic muscles of the hand.

• True

• False

Answer explanation

FALSE: Intrinsic plus hand is caused by imbalances between strong intrinsic (or short) and weak extrinsic muscles of the hand. 

What structure creates the roof of the carpal tunnel and what nerve travels through the tunnel? 

Answer explanation

Transverse carpal ligament;

median nerve 

Multiple choice: Which nerve provides sensory innervation to the lateral 2/3rds of the dorsum of the hand, the dorsum of the thumb, and the proximal parts of the dorsum of the index, middle ½ of the ring finger? 

• Radial

• Ulnar

• Median