LECTURE 3: UPPER EXTREMITY MUSCLE COMPARTMENTS Flashcards
What is the action of the coracobrachialis?
Flexor of the arm (shoulder; crosses shoulder joint)
What is the action of the brachialis?
Flexor (when load is required) and supinator (when elbow is in flex position such unscrewing a cap) of the forearm
What is the innervation to the anterior compartment of the arm?
Musculocutaneous nerve
What is the action of the triceps brachii?
extension of forearm (elbow)
What is housed in the quadrangular space?
has axillary nerve that innervated deltoid and teres minor traveling through
What is the innervation of the posterior compartment of the arm?
radial nerve
What forms the borders of the cubital fossa?
- Brachioradialis muscle
- Pronator teres muscle
- Epicondyles of humerus
What covers the cubital fossa?
bicipital aponeurosis
What is the medial cubital vein?
The median cubital vein (used to draw blood) travels over the aponeurosis and connects the cephalic and basilic veins
What is the path of the radial and ulnar nerve?
- Radial nerve passes under the brachioradialis
* Ulnar nerve passes posterior to the medial epicondyle
What is the innervation of the anterior muscles of the arm?
median nerve (with the exception of flexor carpi ulnaris which is innervated by ulnar nerve)
What is the insertion and action of the flexor digitorum superficialis?
- Inserts in Medial humerus and radius to middle phalanges of digits 2-5
- Flexes digits at metacarpal-phalangeal joint and PIP
What is the insertion and action of the flexor carpi ulnaris?
Inserts onto the medial carpals and flexes and adducts the wrist
What is the insertion and action of the palmaris longus?
Attaches to palmar aponeurosis of hand and flexes wrist, may be absent in some
What is the palmar aponeurosis?
a triangular deep fascia over the palm, extending to the digits
What is the insertion and action of the flexor carpi radialis?
Inserts onto the lateral metacarpals and thus flexes and abducts wrist
What is the insertion and action of the pronator teres?
Attaches to radius and pronates forearm
What is the insertion and action of the flexor digitorum profundus?
Insert on distal phalanges of digits 2-5 and flex DIP (can also flex at PIP, MCP and wrist joint)
What is the innervation of the flexor digitorum profundus?
Innervated by both the ulnar and median nerve
What is the insertion and action of the flexor pollcis longus?
Inserts on phalanx of thumb and flexes the interphalangeal joint and MCP
What is the insertion and action of the flexor protnator quadratus?
- Quadrangular muscle from distal ulna (origin) to radius (insertion)
- Pronation of forearm
What is the innervation of the posterior compartment of the arm?
radial nerve
What is the role of the extensor carpi radialis longus and brevis?
extensors and abductors of the wrist
What is the role of the extensor carpi ulnaris?
Runs from lateral humerus to medial metacarpals and is a wrist extensor and adductor
What is the role of the extensor digitorum and digit minimi?
Extensors of digits 2-5 and 5, respectively
What is the action of the anconeus?
Small triangular muscle posterior to elbow joint, accessory extensor
What is the action of the brachioradialis?
Crosses over lateral elbow joint and is an accessory flexor of the elbow
What is the action of the abductor pollicis longus?
Attaches to lateral metacarpal (of the thumb) to abduct thumb
What is the insertion and action of the abductor extensor pollicis longus and brevis?
Insert on distal and proximal phalanx of thumb, Extend joints of the thumb
What is the insertion and action of the abductor extensor indicis?
Inserts on digit 2 (pointer) to extend that digit
What is the insertion and action of the supinator?
Wraps around lateral side of elbow to supinate the forearm
How is carpal tunnel formed?
Formed by arch of the carpal bones and the overlaying flexor retinaculum (sheet between the carpel bones forming carpal tunnel)
What are the contents of the carpal tunnel?
- Tendons of flexor digitorum profundus
- Tendons of flexor digitorum superficialis
- Tendon of flexor pollicis longus
- Median nerve
What is carpal tunnel syndrome?
Median nerve gets compressed
What is the anatomical snuffbox?
dip in hand
What is the contents of the snuffbox?
- Radial artery
* Scaphoid and trapezium bones form floor (lateral from the first row)
What is the boundary of the snuffbox?
Extensor pollicis longus and brevis tendons
What are the extrinsic muscles of the hand?
Muscles that move the hand (power grip), but muscle bellies lie in the forearm and tendons extend to the hand
What is the innervation of the extrinsic muscles of the hand?
median, ulnar, and radial nerves
What is the innervation of intrinsic muscles of the hand?
ulnar and median nerves
What are the intrinsic muscles of the hand?
Palmaris brevis, palmar and dorsal interossei, adductor pollicis, thenar and hypothenar groups, and lumbricals
What is the palmaris brevis?
- Small quadrangular muscle over the hypothenar eminence
* Improves grip
What is the adductor pollicis?
- Triangular muscle that attaches to proximal phalanx of thumb
- Adducts thumb
What are interossei muscles?
Interossei muscles run between the metacarpals
What is the action of dorsal interossei?
Abduction of digits 2-4
“DABB” 4 muscles
What is the action of palmar interossei?
- 3 muscles
- Adduction of digits 2,4,5
- “PAD”
What is action of the lumbcricals?
- 4 muscles that extend from tendons of flexor digitorum profundus and attach to tissue on phalanges
- Flex MCP joint and extend PIP and DIP joint
What is the action of the oppenens pollicis?
Opposition of thumb
What are muscles of the thenar group?
opponens pollicis, flexor pollicis brevis, abductor pollicis brevis
What is the action of the flexor pollicis brevis?
Flexes thumb at MCP joint
What is the action of the abductor pollicis brevis?
Abducts thumb at MCP joint
What are the muscle of the hypothenar group?
opponens digiti minimi, flexor digiti minimi brevis, abductor digiti brevis
What is the action of the abductor digiti brevis?
Abductor of digit 5
What is the action of the flexor digiti brevis?
Flexes digit 5 at MCP joint
What is the action of the opponens digiti brevis?
Opposition of digit 5
How are the superficial and deep palmar arches formed?
Radial and ulnar arteries enter the hand and form two interconnected arterial arches
What are the pulse points in the arm?
- Axillary
- Brachial (medial to biceps tendon)
- Radial
- Ulnar
What is Allen’s Test?
for adequate contribution of both arteries (radial and ulnar) to the hand
