6 Muscles (Posterior Axioappendicular - Extrinsic Muscles)

Question 1

What are the 4 muscles of the posterior axioappendicular - extrinsic - muscle compartment?

Answer 1

Levator scapulae
Trapezius
Latissimus Dorsi
Rhomboids (major and minor)

Question 2

Practice an oral presentation of the levator scapulae muscle

Answer 2

Location: part of the posterior axioappendicular muscle compartment. Lies deep to the trapezius. Fibres run inferiorly from superior cervical spine to medial scapula

Function:
elevation of the scapula, downwardly rotates glenoid fossa, extension and sidebending of the cervical spine. assists upper trapezius fibres in carrying a load

PA: post tubercles of transverse processes of C1-4 vertebrae

DA: medial border of the scapula, superior to spine of the scapula

NS: dorsal scapular nerve (C5) and cervical nerves C3, C4

Question 3

Practice an oral presentation of the trapezius muscle

Answer 3

Location: part of the posterior axioappendicular muscle compartment.

Structure: a trapezoid shaped muscle. three parts of the trapezius: superior, middle and inferior fibres, each with distinct functions

Function:

superior: elevates scapula, rotates glenoid fossa superiorly
middle: retracts scapula
lower: depresses scapula, rotates glenoid fossa superiorly

PA:
medial third superior nuchal line
nuchal ligament
EOP (external occipital protruberance)
Spinous Processes of C7-T12 vertebrae

DA:
lateral third of clavicle
acromion process
spine of the scapula

NS:

motor: accessory nerve CN XI
sensory: C3-4 spinal nerves

Question 4

Practice an oral presentation of the latissimus dorsi muscle

Answer 4

Location: part of the posterior axioappendicular muscle compartment

Function:
extends humerus
adducts humerus
internally rotates humerus
draws body towards the arms in climbing / overhead actions (swimmers muscle)

PA:
SPs of T7 - T12
thoracolumbar fascia
iliac crest
inferior 3-4 ribs

DA: floor of the bicipital groove of the humerus

NS: thoracodorsal nerve (C6-8)

Question 5

Practice an oral presentation of the rhomboid muscles

Answer 5

Location: part of the posterior axioappendicular muscle compartment. Run obliquely between cervical spine and medial borders of the scapula

Structure:
two components to the rhomboids: minor (superior) and major (inferior)

Function:
retract the scapula
rotate the glenoid fossa inferiorly
stabilise the scapula against the Tx cage

PA: minor: nuchal ligament and SPs of C7-T1
major: SPs of T2-5

DA: minor: medial border of the scapula (superior to spine)
major: medial border of the scapula (inferior to spine)

NS: