Gross Anatomy Tutorial 1 Flashcards
A lesion of the nerve that supplies the supraspinatus muscle results in what deficit?
problems with abduction and external rotation of the humerus, and wasting away of supraspinatus and infraspinatus.
Age-related changes in or an injury to what bony prominence may compromise the integrity of the tendon of the supraspinatus muscle?
Scapula
The nerve that supplies the deltoid muscle is a branch of what cord of the brachial plexus?
Posterior cord (Axillary nerve: upper trunk, posterior division, posterior cord)
What are three actions of the deltoid muscle?
Rotates arm medially and laterally Adducts Abducts Flexes Extends
What is the origin and course of the posterior humoral circumflex artery?
Origin
It is a branch of the axillary artery (subclavian before clavicle, axillary after, then becomes brachial artery at teres major muscle)
Course
The posterior humoral circumflex artery runs with the axillary nerve through the quadrangular space bounded by the teres minor and teres major muscles, the long head of the triceps brachii and the humerus.
It anastomoses with the anterior humoral circumflex artery and an ascending branch of the profunda brachii artery.
It sends a branch to the acromial rete.
What muscles does the posterior humoral circumflex artery supply?
Teres minor
Deltoid
What is the course and origin of the suprascapular artery?
The suprascapular artery is a branch of the thyrocervical trunk. It passes over the superior transverse scapular ligament (whereas the suprascapular nerve passes under the ligament).
Name an important anastamotic connection in which the suprascapular artery participates.
The suprascapular artery anastamoses with the deep branch of the transverse cervical artery (aka dorsal scapular artery) and the circumflex scapular artery around the scapula, providing a collateral circulation.
A lesion to the nerve supplying the triceps brachii muscle group would result in what major functional deficit?
The triceps brachii is innervated by the radial nerve. A lesion would result in the inability to extend the elbow against resistance.
What nerve supplies the rhomboid major muscle?
Dorsal scapular nerve (C5)
Name 2 actions of this muscle.
Retracts scapula
Rotates scapula to rest position
A lesion of the accessory nerve as it enters the trapezius muscle would produce which functional deficits?
Cranial nerve XI, the spinal accessory nerve (SAN), is vulnerable to injury, owing to its long and superficial course in the posterior cervical neck.[1] An important landmark in the neck, the SAN is considered to contribute most motor innervation to the trapezius muscle. Injury to the SAN results in varying degrees of shoulder dysfunction.
Lesion = “shoulder quadrilateral space syndrome” - lose motor fx to teres minor and deltoid muscles, lose sensory to the skin on the upper lateral arm and the capsule of the shoulder joint
What is the nerve supply to biceps brachii?
Musculocutaneous nerve
A lesion of the long thoracic nerve produces what classical syndrome?
“Winging scapula”
Inability to comb hair bc of inability to upwardly rotate scapula, inability to do pushing movements
What muscles does the median nerve supply in the forearm?
The median nerve supplies every muscle in the ANTERIOR forearm BUT: the flexor carpi ulnaris, and half of the flexor digitorum profundis. The median nerve supplies: Protonator teres Flexor carpi radialis Palmaris longus Flexor digitorum superficialis Flexor pollicis longus Pronator quadratus 1/2 of flexor digitorum profundus
The median nerve may become compressed between the two heads of what muscle?
The median nerve can become compressed as it passes into the forearm between the median and ulnar heads of the pronator teres muscle, which it innervates.
What functional deficits would most likely occur as the result of a lesion of the lower subscapular nerve?
Lower subscapular nerve supplies the lower part of the subscapularis muscle, and also supplies the teres major muscle.
A lesion would yield the inability to adduct and rotate the arm medially, which are both functions of both muscles.
Name the other branches of the posterior cord of the brachial plexus besides the lower subscapular nerve, list the muscles that they supply and describe the actions of these muscles
Besides the lower subscapular nerve, the branches of the posterior cord are: upper subscapular nerve, thoracodorsal nerve and axillary nerve.
Innervation:
Upper subscapular nerve –> upper part of subscapularis muscle
Thoracodorsal nerve –> Lattisimus dorsi
Axillary nerve –> deltoid, teres minor muscles, and branches to become the lateral brachial cutaneous nerve
Functions:
Subscapularis –> Adduct and rotate the arm medially
Lattisimus dorsi –> adduct, extend, and rotate the arm medially
Deltoid –> Abducts, adducts, flexes, extends and rotates the arm medially and laterally
Teres minor –> adduct and rotate the arm medially
The suprascapular nerve is a branch of which trunk of the brachial plexus?
Upper trunk
The branches of the upper trunk are suprascapular nerve and the nerve to the subclavius
Name two functional deficits that would occur is the suprascapular nerve were damaged at its origin.
The inability to rotate the arm laterally (infraspinatus)
The inability to abduct the arm (supraspinatus)
Name two functions of the serratus anterior muscle.
- Rotates scapula upward
- Abducts scapula with arm
- Elevates arm above the horizontal
Where does the musculocutaneous nerve terminate?
It continues into the forearm as the lateral antebrachial cutaneous nerve
What muscles does musculocutaneous nerve supply?
Musculocutaneous innervates all of the flexor muscles in the anterior compartment of the arm:
coracobrachialis
biceps brachii
brachialis
What nerve follows the course of the deep brachial artery?
Radial nerve
Where does the deep brachial artery terminate?
The deep brachial artery gives off an ascending branch which anastamoses with the descending branch of the posterior humeral circumflex artery
It terminates when it divides into the middle collateral artery and the radial collateral artery.
What is the primary function of the brachialis muscle on the elbow joint?
Flexes the forearm.
Compare the action of the brachialis muscle with that of the brachioradialis muscle on the elbow joint.
They both flex the forearm.
What is the role of the superficial branch of the radial nerve? The deep branch of the radial nerve?
Superficial branch of radial nerve –> 2 1/2 digits (proximal), innervates radial side of the hand skin
Deep branch of radial nerve –> extensor muscles of the forearm, extensor carpi radialis brevis, supinator
A lesion of the deep branch of the radial nerve would produce what functional deficit at the wrist?
Wrist drop (Saturday night palsy) - inability to extend wrist and fingers
What nerves supply the flexor digitorum profundus muscle?
Ulnar nerve
Median nerve
What is the primary action of the flexor digitorum profundus?
Flexes distal interphalangeal joints and hand
If the ulnar nerve was lesioned at the medial epicondyle, what functional deficits would occur?
Claw hand - ring and little fingers are hyperextended, wasted hypothenal eminence
**Ulnar nerve passes posteriorly to the medial epicondyle
The deep branch of the ulnar nerve supplies what muscles of the hand:
All interosseus muscles
Lumbricals 3 and 4
Adductor pollicis
Flexor pollicis brevis
If the ulnar nerve were compromised in the tunnel of Guyon, what functional deficits would occur?
Ulnar nerve entrapment
Spinster’s claw – looks like the hand of benediction but the latter refers to median nerve damage
Tingling in the hand
Paresthesias
Name 2 actions of the first dorsal interosseus muscle.
The first dorsal interosseous is also able to:
- rotate the index finger slightly at the metacarpophalangeal joint and
- assist adductor pollicis in thumb adduction
How do the actions of the first dorsal interosseus muscle differ from those of the first lumbrical?
The lumbricals:
flex metacarpophalangeal joints, extend interphalangeal joints
The first dorsal interosseous is also able to:
1. rotate the index finger slightly at the metacarpophalangeal joint and
2. assist adductor pollicis in thumb adduction
What is the nerve supply of the flexor carpi radialis muscle?
Median nerve
Median nerve does most flexors.
Blood supply by radial artery
Origin is the common flexor tendon of the medial epicondyle
Crosses diagonally across forearm to insert on thumb side of palm
Flexes wrist
Abducts writs
Name a muscle that acts as a synergist to flexor carpi radialis muscle.
Extensor carpi radialis (backside)
Both abduct the wrist
Name a muscle that acts as an antagonist to flexor carpi radialis muscle.
Also extensor carpi radialis
Carpi means:
crosses the wrist
Flexors are on what side:
Palmar side
Extensors are on what side:
Back of arm side
Anything with radialis in its name does what?
Abducts
Anything with ulnaris in its name does what?
Adducts
A lesion of the thenar branch of the median nerve (aka recurrent branch) would result in what functional deficit?
Thenar wasting
Thenar muscles paralysed, as are the lateral two lumbricals. This affects opposition of the thumb and flexion of the index and middle fingers.
Hand of benediction
How does the median nerve gain access to the palm of the hand?
Carpal tunnel
What is the primary action of the flexor digitorum superficialis in the hand?
The primary function of flexor digitorum superficialis is flexion of the middle phalanges of the fingers at the proximal interphalangeal joints.
What nerve supplies the flexor digitorum superficialis in the hand?
Median nerve (C7, C8, T1)
What nerve pierces the supinator muscle to gain access to the posterior compartment of the forearm?
Deep branch of radial nerve
When the deep branch of the radial nerve exits the supinator muscle, it is called the posterior interosseus nerve.
