Introduction to Brachial Plexus Shoulder Girdle Muscles Flashcards
Anterior branches of fully formed spinal nerves that have exited the
intervertebral foramen
Lateral pectoral nerve
Musculocutaneous nerve
Branches of the lateral cord
Branches of the ____________ of the plexus arise from the cords of the brachial plexus and are approachable through the axilla.
infraclavicular part
Medial pectoral nerve
Medial cutaneous nerve of arm
Medial cutaneous nerve of forearm
Ulnar nerve
Branches of the medial cord
Dorsal scapular nerve (from C5 root)
Long thoracic nerve (from C5, 6, 7)
Nerve to subclavius (From superior trunk)
Suprascapular nerve (From superior trunk)
Four branches of the supraclavicular part
Upper subscapular nerve
Thoracodorsal nerve
Lower subscapular nerve
Axillary nerve
Radial nerve
Branches of the posterior cord
where do the branches head?
laterally / inferiorly away from the midline
the 5 branches form
3 cords
roots pass through _____ muscles on the lateral aspect of the neck and combine to form three trunks
scalene
what roots form the superior trunk
C5 and C6
what root forms the middle trunk
C7
what roots form the inferior trunk
C8 and T1
Each trunk gives off how many branches
Each trunk gives off two branches
Which divisions do each trunk give off
an anterior and posterior division
These divisions pass underneath the ______ as they head towards the ______
clavicle, axilla
Divisions are happening where?
the clavicle
Once the anterior and posterior divisions have entered the axilla, they combine together to form _______
three cords
the three cords are named by their position relative to the
axillary artery
which cord forms from anterior divisions of the superior and middle trunk (lateral to the artery)
the lateral cord
which cord forms from posterior divisions from all three trunks (posterior to the artery)
the posterior cord
which cord forms from the anterior division of the inferior trunk (medial to artery)
the medial cord
what does the axillary artery serve?
the upper limb
originates as a continuation of the subclavian artery
Once in the axilla and the proximal aspect of the upper limb, the three cords give rise to
five major branches
These nerves continue into the upper limb to provide innervation to the ___________ present.
muscles and skin
which cord gives rise to the Musculocutaneous nerve
Lateral cord
which cord gives rise to the Axillary and Radial nerves
posterior cord
which cords gives rise to the median nerve
lateral and median
which cord gives rise to the ulnar nerve
the medial cord
what nerves make up the musculocutaneous
C5-C7
what nerves make up the musculocutaneous Axillary nerve
C5-C6
what nerves make up the musculocutaneous radial nerve
C5-T1
what nerves make up the musculocutaneous medial nerve
C5-T1
what nerves make up the musculocutaneous ulnar nerve
C8-T1
is a flat, triangular muscle, covering the upper and back part of the neck and shoulders.
trapezius
Upper Trapezius: External occipital protuberance and the medial superior nuchal line of the occipital bone, from the ligamentum nuchae, the spinous process of C7
Middle Trapezius: SP of T1 to T5
Lower Trapezius: SP of T6 – T12
Origin of trapezius
insertion of Trapezius
(All three parts together) Lateral 1/3 of clavicle; acromion, Spine of scapula
Function of upper trapezius
- extension and lateral flexion of the head (mostly bilaterally contralateral)
- extension and lateral flexion of the neck
- contralateral rotation of head and neck
- elevation of scapula
- upward rotation of scapula
the function of extrinsic back muscles
movement of the upper limbs
What are the 3 divisions of the tap
Upper fibres, middle fibers and lower fibers
The function of middle trapezius
- retraction (adduction) of scapula
Function of lower trapezius
- depression of scapula
- upward rotation of scapula
which is the weakest of the three sections of the trapezius
the lower
Ori: SPs of C7 & T1
Ins: Medial (vertebral) border of scapula at the root of the spine
rhomboids minor ori and ins
Ori: SPs of T2-T5
Ins: Medial (vertebral) border of scapula inferior to spine
rhomboids major ori and ins
function of rhomboids
- retraction (adduction) of scapula
- elevation of the scapula
- downward rotation of the scapula
innervation of rhomboids
dorsal scalpular nerve
Ori: TPs of C1-C4
Ins: Medial border of scapulae (above the spine of scapula)
Ori and Ins of Levator Scapulae
function of Levator Scapulae
- extension of neck at the spinal joints
- lateral flexion of the neck at the spinal joints
- ipsilateral rotation of the neck at the spinal joints
- elevation of the scapula at the scapulocostal joint
- downward rotation of the scapula at the scapulocostal joint
innervation of Levator Scapulae
Dorsal scapular nerve
Ori: 3rd to 5th ribs
Ins: Coracoid process
Pectoralis minor ori and ins
the function of Pectoralis minor
- protraction of the scapula
- downward rotation of the scapula
- depression of scapula
- elevation of ribs 3-5 at sternocostal and corticospinal joints (during forced inhalation when the scapula is fixed)
innervation of Pectoralis minor
N: Medial pectoral
Ori: First rib
Ins: Subclavian groove of the clavicle
Subclavius ori and ins
Subclavius function
depression of clavicle at the sternoclavicular and acromioclavicular joints
innervation of the Subclavius
nerve to subclavius
Ori: Upper nine ribs
Ins: Anterior surface of vertebral (medial) border of scapula
Serratus anterior ori and ins
Serratus anterior function
protraction (abduction) of scapula
upward rotation of the scapula
innervation of Serratus anterior
N: Long thoracic nerve (C5,6,7)
what is a wing scapula?
when there is an injury to the long thoracic nerve which produces paralysis (weakness) or the serratus anterior muscle
muscle will pop off the ribcage and look like a wing - abnormal protrusion
- will effect the motion of the arm because of the glenohumeral joint
injury to C5C6C7 is a wing to heaven
Ori:
- Clavicular head:
- Medial half of clavicle
Sternocostal head:
- Sternum
- Costal cartilages of 1st to 7th ribs
Ins:
-Lateral lip of intertubercular (bicipital) groove of the humerus
Pectoralis major ori and ins
difference between Pectoralis major and Pectoralis minor
difference in size and do very different things
Function of Pectoralis major
- flexion of arm (clavicular head)
- adduction of the arm
- medial rotation of the arm
- horizontal adduction of the arm
innervation of Pectoralis major
N: Medial and lateral pectoral
is a triangular, flat muscle, which covers the lumbar region and the lower half of the thoracic region.
Latissimus dorsi
Ori:
Spinous process T7 to L5
Crests of ilium & sacrum
Lowest four ribs (via thoracolumbar fascia)
Ins: Floor of the inter-tubercular groove of the humerus
Latissimus dorsi ori and ins
Latissimus dors function
- extension of the arm
- adduction of the arm
- medial rotation of the arm
- anterior tilt of the pelvis
innervation of Latissimus dors
N: Thoracodorsal
