Anatomy dissection 11

Question 1

What is the deltoid muscle innervated by ?

Answer 1

Axillary nerve (hence damage to this gives the badge patch area)

Question 2

What are the attachments of the deltoid muscle ?

Answer 2

• It attaches proximally to the lateral third of the clavicle and the inferior aspects of the scapular spine and acromion
• Attaches distally to the deltoid tuberosity of the humerus

Question 3

What is a common site for cardiac referred pain in the arm ?

Answer 3

The posterior aspect of the arm

Question 4

What are the compartments of the arm ?

Answer 4

Posterior and anterior

Question 5

What are the muscles of the posterior compartment of the arm ?

Answer 5

Triceps brachii - has a lateral, medial and long head

Question 6

What is the innervation of the posterior compartment of the arm ?

Answer 6

Radial nerve

Question 7

What are the attachments of the triceps brachii ?

Answer 7

Proximal Attachments:

• Long head - Infraglenoid tubercle of the scapula
• Lateral head - superior to radial groove of humerus
• Medial head - inferior to radial groove of the humerus

Distal attachment:

All the heads attach to the olecranon process of the ulna

Question 8

What is the function of the triceps brachii ?

Answer 8

Extension of the forearm at the elbow joint and weak extension of the arm at the shoulder joint

Question 9

Where is the axillary nerve found ?

Answer 9

The quadrangular space

Its boundaries are:

• Superior – Subscapularis and teres minor.
• Inferior – Teres major.
• Laterally – Surgical neck of humerus.
• Medially – Long head of triceps brachii.

Question 10

What muscles does the axillary nerve supply ?

Answer 10

Supplies the deltoid and teres minor

Question 11

When must patients have there axillary nerve function tested ?

Answer 11

Followin an inferior dislocation of the shoulder

Question 12

Describe the route of the radial nerve

Answer 12

• Passes from axilla to posterior compartment of the arm (found in the radial groove of the humerus here)
• Then enters lateral aspect of the cubital fossa
• The goes into the posterior compartment of the forearm

Question 13

What is the cubital fossa ?

Answer 13

An area located on the anterior surface of the elbow joint

Question 14

What is the nervous supply of the posterior compartment of the arm ?

Answer 14

Radial

Question 15

The posterior compartment of the arm is similar to the posterior compartment of the leg, its split into superifical and deep muscles, what are the superficial muscles ?

Answer 15

There are 7 muscles:

• Brachioradialis
• Extensor carpi radilais longus and brevis
• Extensor digitorum
• Extensor digit minimi
• Extensor carpi ulnaris
• Anconeus

(the ones with radilis in are because the are on the radial side - the list goes from lateral to medial)

Question 16

What is special about the brachioradialis muscle ?

Answer 16

It is located at the boundry between the anterior and posterior compartments of the forearm

Classified as posterior because supplied by the radial nerve

Question 17

What is the function of the extensor carpi radialis longus and brevis ?

Answer 17

Extension and abduction at the wrist

Question 18

What is the other function of the extensor digit minimi?

Answer 18

Extends the little finger, and extends the wrist

Question 19

What is the function of the brachioradilis muscle ?

Answer 19

Flexes at the elbow

Question 20

What is the function of the extensor digitorum ?

Answer 20

Extends medial four fingers at the MCP and IP joints

Question 21

What is the function of the extensor carpi ulnaris ?

Answer 21

Extension and adduction of wrist.

Question 22

What is the function of the aconeus muscle ?

Answer 22

Extends and stablises the elbow joint. Abducts the ulna during pronation of the forearm.

Question 23

What are the deep muscles of the posterior compartment of the forearm ?

Answer 23

• Supinator
• Abductor pollicis longus
• Extensor pollicis brevis and longus
• Extensor indicis.

Question 24

What is the function of the supinator muscle of the deep posterior forearm ?

Answer 24

Supinates the forearm

Question 25

What is the function of the extensor pollicus longus and brevis ?

Answer 25

Extension of the thumb

Question 26

What is the function of the abductor pollicus longus ?

Answer 26

Abducts the thumb

Question 27

What is the function of the Extensor indicus ?

Answer 27

Extension of the index finger

Question 28

What is a wrist drop a clinical sign of ?

Answer 28

Radial nerve injury

Question 29

What are the tendons of the muscles of the posterior comapartment of the forearm held in place by as they cross the wrist ?

Answer 29

Extensor retinaculum

Question 30

Where does the radial nerve branch into superifical and deep (note if it wants to be really specific guess deep radial nerve for supply of posterior forearm muscle)

Answer 30

Just anterior to the lateral epichondyle

Question 31

Note the the deep radial nerve can be called the posterior interosseous nerve