3.4. Innervation of Brachia, Antebrachia, and Hands Flashcards
Sort the muscles according to their innervations
Identify the nerves that innervate each cutaneous region
Which muscles and cutaneous regions are innervated by the axillary nerve? What movements are caused at each muscle?
See notes for movements
Lateral Muscles of Brachia and Antebrachia
- Teres Minor (Posterior Pectoral Girdle)
- Deltoid (Anterior Brachia)
- Upper lateral arm
Which muscles and cutaneous regions are innervated by the musculocutaneous nerve? What movements are caused at each muscle?
See notes for movements
MUSCLES: MOST Flexors/Anterior of Brachia Excluding pectoralis major and deltoid
- Biceps Brachii (ant brachia)
- Brachialis (ant brachia)
- Coracobrachialis (ant brachia)
CUTANEOUS:
CONTINUES INTO THE LATERAL CUTANEOUS NERVE OF THE FOREARM
- Lateral antebrachia
Which muscles and cutaneous regions are innervated by the radial nerve? What movements are caused at each muscle?
See notes for movements
MUSCLES:
MOST Flexors/Anterior of Brachia Excluding pectoralis major and deltoid
- Biceps Brachii (ant brachia)
- Brachialis (ant brachia)
- Coracobrachialis (ant brachia)
CUTANEOUS:
- Post and lateral brachia
- Post antebrachia
- Posterior lateral palm excluding thumb
- Skin covering thenars
Which muscles and cutaneous regions are innervated by the median nerve? What movements are caused at each muscle?
See notes for movements
Muscles:
- MOST Flexors/Anterior of Antebrachia, AND thenars and some lumbricals*
- Except flexor carpi ulnaris and medial half of flexor digitorum profundus*
- Pronator Teres (Ant sup antebrach)
- Flexor Carpi Radialis (Ant sup antebrach)
- Palmaris Longus (Ant sup antebrach)
- Flexor Digitorum Superficialis (Ant mid antebrach)
- Flexor Pollicis Longus (Ant deep antebrach)
- LATERAL half of flexor digitorum Profundus (ant deep antebrach)
- Pronator Quadratus (ant deep antebrach)
- SOME lumbricals
CUTANEOUS:
- Anterior digits 1-3
- Posterior digit tips 1-3
Which muscles and cutaneous regions are innervated by the ulnar nerve? What movements are caused at each muscle?
See notes for movements
MUSCLES:
SOME Flexors/Anterior of Brachia AND palmar interossei, dorsal interossei, and most lumbricals
- Flexor Carpi Ulnaris (ant sup antebrachia)
- MEDIAL half of flexor digitorum Profundus (ant deep antebrachia)
- MOST lumbricals (ant and post hand)
- Palmar Interossei (ant hand)
Dorsal Interossei (ant hand)
CUTANEOUS:
- Anterior and posterior digits 4-5
Which nerve innervates the extensor muscles of the arm?
Radial
Which artery supplies the arm?
Brachial
What movements can be performed at the distal interphalangeal joints?
Flexion/extension
Name the superficial veins of the upper limbs
Basilic and Cephalic
The muscles that cross the anterior aspect of the wrist joint contract to produce…
Flexion
The skin on the anterior aspect of the little finger (5th digit) is supplied by which nerve?
Ulnar nerve provides cutaneous innervation to the medial palm and medial 1.5 digits
Name the four muscles that form the rotator cuff of the glenohumeral (shoulder) joint.
Supraspinatus, Infraspinatus, Teres Minor, and Subscapularis
Name the three muscles innervated by the musculocutaneous nerve
Coracobrachialis, Brachialis, Biceps Brachii
All located in anterior brachia and are flexors of the glenohumeral and/or elbow joints
What is the action(s) of the flexor carpi radialis muscle at the wrist?
Flexion because it crosses the anterior aspect of the wrist joint. It performs this action with flexor carpi ulnaris
Abduction (radial deviation) because it crosses the lateral aspect of the wrist joint. It performs this action with the extensor carpi radialis longus and extensor carpi radialis brevis.
Describe the articular surfaces, joint classification and movements of the elbow joint.
Classification: Synovial Hinge
Articular Surfaces: Capitulum of humerus with head of radius (humeroradial joint) and trochlea of the humerus with trochlear notch of the ulna (humeroradial). The proximal radioulnar joint between the radius’ head with radial notch of the ulna shares the joint capsule.
Movements: Flexion and Extension
A carpenter cuts his forearm while using an electric band saw. The doctor examined his arm and forearm, and noticed he had what is called a ‘wrist drop’ (cannot extend the wrist). Which nerve might have been damaged?
He is likely to have cut his radial nerve (which supplies the extensor muscles of the wrist that are located in the posterior forearm). Therefore he cannot extend his wrist and the wrist goes into unopposed flexion. I.e. Wrist drop.
At the cafe you take a drink of your soy decaf latte with an orange twist.
a. What movements are you making to get the glass from the table to your mouth?
b. What muscles are you using at the shoulder and elbow joints?
Elbow flexion- Biceps brachii, brachialis, brachioradialis
Shoulder flexion- Deltoid, coracobrachialis, biceps brachii, and pectoralis major
Also, to hold the glass:
Flexion of the metacarpophalangeal and interphalangeal joints and wrist/radiocarpal joint - flexor digitorum profundus, fleor digitorum superficialis, flexor carpi radialis, and flexor carpi ulnaris
One of your friends tells you that he is unable to abduct his glenohumeral (shoulder) joint.
a. Which muscle(s) are most likely to be affected? (i.e. which muscles abduct the shoulder joint?)
b. Which nerve is most likely to be affected? (i.e. which nerve innervates the abductor muscles of the shoulder joint?)
a. Deltoid, supraspinatus
b. Axillary nerve (innervates deltoid)
* Don’t need to know that suprascapular nerve innervates supraspinatus*
- What muscle attaches to the region labelled A?
- Identify the ligament or tendon labelled B?
- Subscapularis
- Coracoacromial Ligament
- Identify the three muscles bordering the anatomical snuff box: from lateral to medial
- Identify the artery labelled A
- Abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus
- Radial Artery
- Identify the bony landmark labelled A
- List the muscles, ligaments, and bursae that attach onto A
- Olecranon
- Triceps Brachii’s distal tendon and the medial collateral ligament of the elbow joint (between humerus epicondyle and ulna’s coronoid process) and the subtendnous bursa (between ulna’s olecranon and the biceps brachii tendons)
- Identify the muscle labelled A
- What is B innervated by?
- Palmaris Longus (notice that it divides into 4 tendons under the flexor retinaculum!)
- Radial Nere (radial nerve innervates ALL extensors/posterior of antebrachia)
- Which movements are possible at the joint labelled A?
- Identify the bone labelled B
- Abduction/adduction and flexion/extension (rotation, or pronaton/supination is at the proximal and distal radioulnar joints!)
- Hamate
- What movement is occurring at the left glenohumeral joint?
- What muscle is the major contributor to the movement occurring at the left glenohumeral joint?
- Abduction
- Deltoid
- Identify the nerve labelled A
- What cutaneous region is innervated by A?
- Radial
- Posterior lateral brachia, posterior antebrachia, posterior lateral hand excluding thumb, and skin covering thenars
- Identify the vein labelled A
- What vein connects the cephalic and basilic veins at the cubital (elbow)
- Basilic (medial superficial)
- Median cubital vein
- The five major arteries of the upper limb, from proximal to distal, are:
- Identify the artery labelled A
- Subclavian, axillary, brachial, radial, and ulnar
- Brachial (is distal to the inferior border of the teres major)
- Identify the structures labelled A
- What digit of the hand does abduction/adduction occur in reference to?
- Lumbricals
- 3rd
