1.4.5. Extrinsic Muscles of the Shoulder Flashcards
What is the Definition of “Extrinsic Muscles of the Shoulder”?
Muscles which Originate from the Torso and Attach to the Bones of the Shoulder
What are the 3 Bones of the Shoulder?
- Clavicle
- Scapular
- Humerus
What are the “Extrinsic Muscles of the Shoulder” also known as?
Superficial Back Muscles
How many layers are the Extrinsic Muscles of the Shoulder are there?
2
What are the 2 Layers of the Extrinsic Muscles of the Shoulder?
- Superficial
2. Deep
What are the 2 Superficial Extrinsic Muscles of the Shoulder?
- Trapezius
2. Latissimus Dorsi
How is the Trapezius described?
- A Broad, Flat, Triangular Muscle - The muscles on each side forming a Trapezoid Shape
- The most Superficial of all the Back Muscles
Where does the Trapezius attach onto the Torso?
- Base of the Skull (Where this Originates from)
- Nuchal Ligament
- Spinous Processes of C7 to T12
Where does the Trapezius attach onto the Shoulder Bones?
- Clavicle
- Acromion
- Spine of the Scapula
What is the Motor Innervation of the Trapezius?
Accessory Nerve (Cranial Nerve XI)
What provides the Proprioception Fibres to the Trapezius?
C3 and C4 Spinal Nerves
What are the 3 Divisions (Bands) of the Trapezius?
- Upper (Superior)
- Middle
- Lower (Inferior)
What is the function of the Upper (Superior) Fibres of the Trapezius?
- Elevation of the Scapula
2. Rotation of the Scapula during Abduction of the Arm
What is the function of the Middle Fibres of the Trapezius?
Retraction of the Scapula
What is the function of the Lower (Inferior) Fibres of the Trapezius?
Pull the Scapula Inferiorly
How is the Latissimus Dorsi described?
Originating from the Lower Back and Covering a Large Area
Where does the Latissimus Dorsi attach onto the Torso?
- Spinous Processes of T6 to T12
- Iliac Crest
- Thoracolumbar Fascia
- Inferior 3 Ribs (10, 11, 12)
- Where does the Latissimus Dorsi attach onto the Shoulder Bones?
- What happens to the Fibres as they attach onto the Shoulder Bones?
- Intertubercular Sulcus of the Humerus
2. The Fibres converge into a Tendon
What is the innervation of the Latissimus Dorsi?
Thoracodorsal Nerve
What is the function of the Latissimus Dorsi?
- Extension of Upper Limb
- Adduction of the Upper Limb
- Medial Rotation of the Upper Limb
Where are the Deep Extrinsic Muscles of the Shoulder Located?
- In the Upper Back
2. Deep to the Trapezius
What are the 3 Deep Extrinsic Muscles of the Shoulder?
- Levator Scapulae
- Rhomboid Major
- Rhomboid Minor
How is the Levator Scapulae described?
A Small, Strap-Like Muscle beginning in the Neck and Descending to Attach to the Scapula
Where does the Levator Scapulae attach onto the Torso?
The Transverse Processes of C1 to C4
Where does the Levator Scapulae attach onto the Shoulder Bones?
The Medial Border of the Scapula
What is the innervation of the Levator Scapulae?
The Dorsal Scapula Nerve
What is the function of the Levator Scapulae?
Elevate the Scapula
Which, of Rhombod Major and Rhomboid Minor, is situated Superiorly?
Rhomboid Minor
Where does the Rhomboid Major attach onto the Torso?
Spinous Processes of T2 to T5
Where does the Rhomboid Major attach onto the Shoulder Bones?
Medial Border of the Scapula, between the:
- Spine of the Scapula
- Inferior Angle of the Scapula
What is the innervation of the Rhomboid Major?
Dorsal Scapular Nerve
What are the functions of the Rhomboid Major?
- Retracts the Scapula
2. Rotates the Scapula
Where does the Rhomboid Minor attach onto the Torso?
Spinous Processes of C7 to T1
Where does the Rhomboid Minor attach onto the Shoulder Bones?
Medial Border of the Scapula, at the Level of the Spine of the Scapula
What is the innervation of the Rhomboid Major?
Dorsal Scapular Nerve
What is the function of the Rhomboid Major?
- Retracts the Scapula
2. Rotates the Scapula
