Lecture Notes: Palpation of Wrist Flexors and Extensors

Overview

• Flexors of the wrist: Located on the anterior forearm (non-hairy side)
• Extensors of the wrist: Located on the posterior forearm (hairy side)

Tools for Identifying Muscles

• Brachioradialis (divider muscle) Test: Flexors medial to brachioradialis; extensors lateral to brachioradialis

Extensor Muscles

General Function

• Originate from the lateral epicondyle of the humerus
• Extend the wrist and digits

Extensor Carpi Radialis Longus and Brevis

• Origin: Longus from the supracondylar ridge; Brevis from the lateral epicondyle
• Insertion: Longus at base of second metacarpal; Brevis at base of third metacarpal
• Palpation Technique: Support elbow, have client abduct/adduct wrist to feel muscle contraction, and follow muscle down the forearm

Extensor Digitorum

• Origin: Lateral epicondyle
• Insertion: Middle and distal phalanges of digits 2-5
• Palpation Technique: Have client wiggle fingers or extend wrist and digits; tendons pop up on the dorsum of the hand

Extensor Carpi Ulnaris

• Origin: Lateral epicondyle
• Insertion: Base of fifth metacarpal
• Palpation Technique: Have client adduct/abduct wrist; follow muscle from lateral epicondyle to base of fifth metacarpal

Summary of Extensors

• Extensor Carpi Radialis Longus: Lateral humerus to base of second metacarpal
• Extensor Carpi Radialis Brevis: Lateral humerus to base of third metacarpal
• Extensor Digitorum: Lateral humerus to digits 2-5
• Extensor Carpi Ulnaris: Lateral humerus to base of fifth metacarpal

Flexor Muscles

General Function

• Originate around the medial epicondyle
• Flex the wrist and digits

Flexor Carpi Radialis

• Origin: Medial epicondyle
• Insertion: Base of second and third metacarpals
• Palpation Technique: Have client flex wrist, locate tendon near thumb, follow muscle from wrist to medial epicondyle

Palmaris Longus

• Origin: Medial epicondyle
• Insertion: Palmar fascia
• Palpation Technique: Have client flex wrist, locate tendon in center, follow muscle up to medial epicondyle. Thumb-to-fifth digit maneuver also helps

Flexor Carpi Ulnaris

• Origin: Medial epicondyle
• Insertion: Pisiform, hook of hamate, base of fifth metacarpal
• Palpation Technique: Have client flex wrist, locate tendon near ulna, follow muscle from wrist up to medial epicondyle

Summary of Flexors

• Flexor Carpi Radialis: Medial humerus to base of second/third metacarpals
• Palmaris Longus: Medial humerus to palmar fascia
• Flexor Carpi Ulnaris: Medial humerus to base of fifth metacarpal