upper limb innervation Flashcards
The brachial plexus is made up of … rami of spinal nerves … to …
Ventral rami, C5 to T1
Name the different parts of the brachial plexus
Roots, trunks, divisions, chords + branches
The rami of C5 and C6 converge to form the … trunk
Superior
C7 forms the … trunk
Middle
C8 and T1 converge to form the … trunk
Inferior
The trunks of the brachial plexus have 2 …
Divisions, anterior + posterior
The posterior divisions of the brachial plexus converge to form the …
Posterior chord
Name the nerves that arise from the branches of the posterior chord of the brachial plexus …
Subscapular, thoracodorsal, axillary + radial
The nerves that arise from the posterior chord of the brachial plexus innervate the … compartment of the upper limb
Posterior
The chords of the brachial plexus are named based on their position regarding the … portion of the … artery
2., axillary
Name the 3 chords of the brachial plexus
Medial, lateral + posterior
Each chord divides into … main branches
2
Name the 2 main branches that arise from the posterior chord of the brachial plexus
Radial + axillary nerve
Name the 2 main branches that arise from the medial chord of the brachial plexus
Ulnar + median nerve
Name the 2 main branches that arise from the lateral chord of the brachial plexus
Musculocutaneous + median
Name the 2 muscles through which the ventral rami of the spinal nerves of the brachial plexus pass
Anterior + middle scalene muscles
Which muscle is innervated by the long thoracic nerve?
Serratus anterior
What’s the name of the condition that appears when the long thoracic nerve is injured (hint: there’s a lack of scapular protraction during arm movement)
Winged scapula (scapula alata)
Name the 2 nerves that innervate the pec major
Lateral + medial pectoral nerves
Name the nerve that “pierces” through the clavipectoral fascia + innervates the pec major
Lat. pectoral nerve
The medial pectoral nerve runs between 2 vessels. Name them
Axillary artery + vein
The 2 radial nerves “connect” in front of an artery. Name it
Axillary artery
The medial pectoral nerve pierces through the …, innervating it
Pec minor
The subscapular nerves originate from the … chord, innervating 2 muscles. Name them
Posterior chord, subscapularis + teres major
Name the nerve that innervates the latissimus dorsi
Thoracodorsal nerve
Explain the trajectory of the thoracodorsal nerve
It accompanies the thoracodorsal vessels along the anterolateral surface of the latissimus dorsi
Which nerve perforates the coracobrachialis + descends towards the forearm between the biceps + brachialis?
Musculocutaneous
The lateral antebrachial cutaneous nerve derives from the musculocutaneous nerve. It perforates a fascia between 2 muscles to give rise to that nerve. Name the 3 structures
Deep fascia, between the biceps + the brachioradialis
Name the nerve that innervates the skin + fascia of the proximal medial part of the arm
Medial brachial cutaneous nerve
Name the nerve that pierces the deep fascia of the forearm + accompanies the basilic vein to the anterior surface of the elbow
Medial antebrachial cutaneous nerve
Which nerve innervates the medial region of the forearm?
The medial antebrachial cutaneous nerve
Which nerve is a cutaneous branch of T2 + innervates the medial cutaneous region of the arm?
The intercostobrachial nerve
Anterior to which muscle does the first portion of the axillary nerve descend?
Subscapularis muscle
Alongside with which vessels does the axillary nerve pass to the back?
Posterior humeral circumflex
The posterior humeral circumflex vessels + the axillary nerve pass through a space to the back. What is it called?
Quadrangular space
The motor trunk of the axillary nerve surrounds a part of the humerus. Which one is it?
The neck
Does the median nerve give a branch in the arm?
No
Name the nerve that descends laterally to the brachial artery
Median
The median nerve, once it passed under the bicipital aponeurosis, gives rise to 2 branches for 2 muscles. Which are they?
Palmaris longus + flexor carpi radialis
The median nerve enters the forearm by passing between the 2 heads of a muscle (together with the ulnar artery). Name that muscle
Pronator teres
The flexor pollicis longus, lateral 1/2 of FDP and pronator quadratus are innervated by a branch of the median nerve. What is it called?
Anterior interosseous nerve
The main trunk of the median nerve descends through the deep surface of the …, innervating it
FDS
At the level of the wrist, the median nerve gives rise to a branch that becomes superficial + innervates the cutaneous region of the thenar eminence. What is its name?
Palmar cutaneous branch
Does the median nerve enter into the hand through the carpal tunnel?
Yes
Name the muscles of the hand that are innervated by the motor (recurrent) branch of the median nerve
Abductor pollicis brevis, opponens pollicis, flexor pollicis brevis
The 3 common palmar digital nerves arise from the … nerve and provide 2 proper palmar digital nerves for the … to … fingers
Median, 1. to radial half of the 4.
The proper palmar nerves send dorsal branches (dorsal digital nerves) to innervate the … of the dorsal surfaces of the distal phalanx of the thumb and the 3. to 5. fingers
Skin
Explain the trajectory of the ulnar nerve with regards to the triceps (arm)
It descends in front of it in the medial region
Where does the ulnar nerve cross the intermuscular septum (in the arm)?
At the distal half of it
Between which 3 structures does the ulnar nerve enter the forearm?
The medial epicondyle, olecranon + flexor carpi ulnaris
Name the 2 muscles of the foream that are innervated by the ulnar nerve
Flexor carpi ulnaris + medial half of the FDP
At which portion of the arm does the ulnar nerve join the ulnar artery?
Middle 1/3
The cutaneous branch of the ulnar nerve innervates … and …
The back of the hand and fingers (in the most ulnar region)
Name the 2 branches of the ulnar nerve
Deep (motor) and superficial (sensitive)
The deep branch of the ulnar nerve innervates …
The muscles of the hypothenar eminence, the interossei, the 3. and 4. lumbrical muscles + the adductor pollicis
The superficial branch of the ulnar nerve gives branches to …
The pinky + medial (ulnar) half of the 4. finger
The radial nerve descends in the arm between an artery and a muscle. Name them
Humeral artery + long head of the triceps
The radial nerve branches off inferolaterally with the …
Deep brachial artery
Where is the canal of the radial nerve located?
Deep to the lateral head of the triceps
In the lateral epicondyle, the radial nerve gives branches to innervate 3 muscles of the forearm. Name them
Brachioradialis, extensor carpi radialis longus + brevis
Name the 2 main branches of the radial nerve + where they arise
Superficial (sensory) + deep (motor), elbow
The brachioradialis covers one of the 2 main branches of the radial nerve (along with the radial artery) as they descend into the forearm. Which one is it?
Superficial branch
The … branch of the radial nerve passes between the 2 portions of the brachioradialis (innervating it)
Deep
The deep branch of the radial nerve surrounds laterally + posteriorly the neck of the radius, in between the 2 layers of a certain muscle. Name it
Supinator
What’s the name of the deep branch of the RN as it leaves the supinator muscle + remains between the superficial and deep extensor planes?
Posterior interosseous nerve
The deep RN branches into 2 main branches. Name them and the structures they innervate
Superficial: extensor digitorum, extensor digiti minimi + extensor carpi ulnaris
Deep: extensor pollicis longus + brevis, extensor indicis, abductor pollicis longus
